THE 1992 CONGRESSIONAL HEARINGS!

TMJ IMPLANTS INC. June 2, 1992

Honorable Ted Weiss
Congress of the United States
House of Representatives
Human Resources and Intergovernmental Relations Subcommittee
Rayburn House Office Building, Room B372
Washington, DC 20815-6148

Dear Congressman Weiss:
Thank you for your letter of May 28. This letter provides an overview of the medical need for and use of the Fossa-Eminence and Condylar Prostheses currently manufactured and distributed by TMJ Implants, Inc. for the treatment of severe temporomandibular joint problems. These products were first introduced in the early 1960's and have been successfully used for over 30 years. The Fossa-Eminence Prosthesis is intended for replacement of the articular disc of the temporomandibular joint in cases of internal derangement, meniscal perforation, adhesions or ankylosis, and can be used individually or in conjunction with the Condylar Prosthesis. The Condylar Prosthesis is intended for use in conjunction with the Fossa-Eminence Prosthesis to form a total prosthetic temporomandibular joint where there is a loss of condylar height, loss of meniscus with fibrous adhesions, or bony ankylosis.
First, let me state that my background is that of a oral and maxillofacial surgeon who practiced from 1948-1988. For most of these years, much of my practice was devoted to surgery of the temporomandibular joint. I was an assistant clinical professor of surgery in the Department of Head and Neck Surgery at the Medical School of the University of California, Irvine, California, in the 1960's to 1970's. My ciricula vitae is provided as Attachment 1. cont'd on page 300
17301 West Colfax Avenue Suite 275 Golden, Colorado 80401
303-277-1338 Fax-303-277-1421
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Having performed scores of surgeries on the temporomandibular joints of patients, beginning in the early 1950's. I realized a more universal and dependable surgery was sorely needed. In 1960, I developed a method of plating the base of the skull with a highly polished metal fossa-eminence implant which would allow the disc and condyle to function smoothly against the nonchanging metal prosthesis.
In 1961, I placed my first Fossa-Eminence Prosthesis in the joint of a patient who had had two previous joint surgeries performed by another surgeon a few years earlier. That particular patient has been followed by me for over 31 years and is doing very well (See, Attachment 2). The year following my first surgery, she required a Fossa-Eminence Prosthesis in her opposite joint and it, too, has done well over all these years. Twenty-five years after placing her first implant, it was necessary to place a Condylar Prosthesis on the first side due to degeneration of the patient's mandibular condyle. The subsequent surgery was in no way related to the performance of the previously implanted Fossa-Eminence Prosthesis. Indeed, at that time I was able to re-examine the original Fossa-Eminence Prosthesis which appeared just as I had placed it over a quarter of a century earlier and continued to be fully functional. Both the original Fossa-Eminence and the subsequently implanted Condylar Prostheses have performed well together, relieving the patient's pain and disability.
Since, 1961 over 3,000 patients have across the United States have been operated on and have received partial (Fossa-Eminence Prosthesis only) or total (Fossa-Eminence and Condylar Prostheses) joint replacement. Many of these were patients who had as many as 20 previous surgeries using other devices or alternative surgical procedures without success, and for who the TMJ Implants, Inc. prostheses were able to provide relief.
Over the nearly 30 years during which I used this technique to restore a degenerated temporomandibular joint I never had to remove an implant due to its failure, looseness, infection, or any other related incidents. This technique is now used successfully by several surgeons and in several hundred hospitals across America. It is also used in numerous university teaching institution. Patient and physician satisfaction of the products and clinical results have resulted in increased product demand.
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(See, Attachment 3). Having had the opportunity of assisting many surgeons and teaching many more I have had first hand opportunity of seeing this technique help many patients.
Consistent with my own experience, other clinicians have had very few incidents of problems with this technique. I am aware of one patient with an allergy to the metal alloy and another patient where a fracture of the Condylar Prosthesis required explantation. Subsequent investigation of the fractured condyle has led us to believe that the fracture was caused by the surgeon attempting to bend the implant prior to implantation, despite the fact that product labeling clearly warns oral surgeons not to bend the prosthesis. There have also been one or two cases of post surgical infection which were not related to the implant, but due to the patient's resistance or to the surgical procedure itself. Except for these few incidents, I am aware of virtually no reported incidents of product failure or other occurrence which as in any way resulted in patient injury or other adverse consequences.
The usefulness of the Fossa-Eminence and Condylar Prostheses for treatment of severe degenerative joint disease is further supported by the preliminary of an ongoing clinical study conducted by the University of Pennsylvania (Attachment 4). A two year follow report of partial or total temporomandibular joint reconstruction on 57 cases concluded that joint reconstruction is an acceptable surgical technique. Pub-
lication of detailed study results are expected late this summer.
We hope this information has been a help to the Committee.
Sincerely,
TMJ IMPLANTS, INC.
signed
Robert W. Christensen, D.D.S.
President
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MANDIBULAR JOINT ARTHROSIS
CORRECTED BY THE INSERTION
OF A CAST-VITALLIUM GLENOID
FOSSA PROSTHESIS:
A NEW TECHNIQUE
Robert W. Christensen, D.D.S.
Pasadena, Calif.
Reprinted from
ORAL SURGERY, ORAL MEDICINE AND
ORAL PATHOLOGY
ST. LOUIS
VOL. 17, NO 6, Pages 712-722, June, 1964
(Copyright (C) 1964 by The C. V. Mosby Company)
(Printed in the U.S.A.)
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MANDIBULAR JOINT ARTHROSIS CORRECTED BY THE INSERTION OF A CAST
-VITALLIUM GLENOID FOSSA PROSTHESIS: A NEW TECHNIQUE
Report of a Case
Robert W. Christensen, D.D.S., Pasadena, Calif.

Degenerative mandibular joint conditions are of frequent occurrence and offer the dental profession a challenge in diagnosis and treatment.
This article will not attempt to discuss the many factors which may con-tribute to the changes which occur in the joint. Instead, it will be limited to a brief presentation of mandibular joint arthrosis and will describe my technique for correction of the problems that were encountered in a particular case.
First, however, it is apparent that a neuromuscular imbalance is probably the greatest factor causing the derangement of the mandibular joint.1 Other factors which predispose the joint to ankylosis are birth trauma, hemarthrosis, infections, fractures of the condyle, tumors, rheumatoid arthritis or osteoarthritis, anatomic variations in the condyle or articular eminence, or surgical procedures on the mandibular joint (especially meniscectomy).
At time the patient may be unaware of the early stages of mandibular joint degeneration until perforation, or ever maceration, of the articular disc has occurred and early changes in the bony articular surfaces of the joint have begun.
If the perforation of the disc is small, we see, radiographically, a limited
point of contact between the anterior surface of the condyle and the posterior surface of the articular eminence. This contact, being pathologic, causes resorptive processes in the articular surface of the temporal bone (Fig. 1) and frequently, to a lesser degree, at the surface of the condyle.
This causes the condyle to move with more difficulty, and usually with pain and grating, when sliding over the roughened surface of the articular eminence. More traction is required by the external pterygoid muscle whose fibers attach to the most anterior rim of the condyle. This traction produces the lipping which is seen in this area of the condyle (Fig. 2). Pressure resorption causes a flattening of the articular surfaces of both condyle and articular eminence in an attempt to minimize the plane of inclination which the condyle must travel. The resorptive phase may be followed by varying degrees of osteosclerosis of the articular surfaces.
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Insert Figures 1 & 2
During this period of degeneration the pain factor may assist in limiting condylar mobility, and fibrous attachment from condyle to fossa may develop. In time fibro-osseous ankylosis develops, which will be followed by complete bony ankylosis.
Generally speaking, the fibrous or osseous ankylosis requires the same type of treatment with, perhaps, slight variations in technique. Surgical inter-
vention is the only possible way of helping the patient with any type of ankylosis.2
Over a period of many year, previous authors have advocated either no treatment or high condylectomy for fibrous ankylosis and osteoarthrotomy for osseous ankylosis.3 A more uniform approach to both types of ankylosis would seem to be welcome. Every effort should be directed toward restoring a reason-
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ably anatomic joint surface and to create the most nearly normal and pain-free joint function possible.
In the previously reported articles on osteoarthrotomy of the mandibular joint, various procedures have been recommended, ranging from placing nothing in the new joint space to the use of fascia, muscle, cartilage, plastic, or metal.
Good results have been reported with each variety of osteoarthrotomy. In a case that I reported in 1955 I placed no new material between the two bone surfaces, and the patient has done well for 9 years.4
Ideally, it would seem that a rigid mechanical barrier of anatomic shape should be most valuable. For that reason, I have devised a metal prosthesis which is anatomic, creates a permanent barrier, and is well tolerated.
The problem that has faced oral surgeons who might have wished for an anatomic prosthesis is: How does one know the shape of the particular bone prior to surgery? Most attempts have been focused on attempting to restore a lost condyle or to cover the condylar stump with a nonanatomic barrier. The most promising procedure, from a strictly biomechanical point of view, would be to place the prosthesis against the base of the skull where unusual lateral pressures would not tend to loosen it.
Fibrous Ankylosis--It occurred to me that, in the case of a fibrous anky-
losis where it is possible to define the glenoid fossa and articular eminence both radiographically and clinically, we should be able to cover this surface with a thin, anatomic cast-Vitallium prosthesis.
With this premise, I decided to make castings to cover the glenoid fossa, articular eminence, and adjacent zygomatic process on each of twenty skulls (Fig. 3). The castings were made 0.022 inch thick and were perforated on the surface covering the zygoma and lateral articular eminence with numerous holes for the 5 mm. cast-Vitallium implant screws which would be used for anchorage. The articular surface is highly polished, while other surfaces and margins are sandblasted. This thickness of Vitallium has also some resiliency and can be formed slightly with pliers to allow for last-minute variations in contour.
The borders are extended, as shown in the photograph, to include the glenoid fossa, articular eminence, and lateral surfaces of both, on to the lateral aspect of the zygomatic process of the temporal bone (Fig. 4).
In the preparation of this type of prosthesis for any given case, it is im-portant to have accurate roentgenograms of the joint in order to obtain as much information as possible concerning the anatomic shape of the joint.
Osseous Ankylosis--In cases of osseous ankylosis, the procedure needs to be varied slightly because of the loss of normal anatomic contour of the joint. In such cases it is necessary to perform an osteotomy below the normal glenoid fossa and attempt to make it at the level of the articular eminence. In so doing, one can be sure not to perforate the cranial cavity. In the past, it has been suggested that, if possible, the condylar head, of at least a 1 cm. segment of bone, be removed. This has been necessary when no mechanical barrier has been placed in the area. In some cases, when a large segment of bone has been removed the powerful elevator muscles have tended to close the bone gap, thus allowing a refusion to develop and at times permitting an open-bite to occur.
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INSERT FIGURES 3 & 4
By using many skulls and filling the glenoid fossa with modeling compound or plasticene, one can make a pattern which will lie on the external surface of the condyle, fossa, and eminence and determine just how the cuts should be made. If this small pattern is fixed with screws to the bone, then one can follow the exact curvature of the osteotomy which will be most suitable. By making the final prosthesis like the previously mentioned glenoid fossa and articular eminence, but following the contour of the pattern, one can be sure that it will slide into place following the osteotomy. In this case, the condylar head can be left in the fossa and the prosthesis can be attached to it. This decreases the hazards attached to removal of the condyle. The thickness of the prosthesis can be from 0.014 to 0.022 inch, so that varying degrees of adaptability can be selected. For this purpose, these thicknesses give ample rigidity and act as a permanent barrier to a recurrence of the ankylosis of the joint. It is conceivable that tantalum, about 0.019 inch in thickness, could be fabricated at the time of surgery and would also be useful. I have preferred cast-Vitallium for its rigidness and also for the fact that the articular surface can be highly polished, thus giving it a smooth surface for the condyle to function against.
In all cases of ankylosis of one or both mandibular joints, it is wise to correct the disease surgically, since, over a period of time, a fibrosis may occur in the elevator muscles, thus causing an additional type of restriction which is difficult to relieve.
CASE REPORT
Sister L., a 35-year-old nun, was referred to my office on Dec. 5, 1960, for consultation regarding an intermittent, dull pain in the right mandibular joint, which has been present for 2 to 3 years. Pain to a lesser degree was noted in the left mandibular joint.
Past History.--The patient stated that when she was 7 years old when was struck in the left temporal area by the pedal of a bicycle. A scar was visible in the skin for many years.
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She received no tretment at the time and did not recall having had any serious problem with the joint until she was in her early 20's, at which time pain became constant. At that time (1948) a surgeon she visited in another city performed a meniscectomy.
The patient stated that she had experienced joint pain, cracking, and periods of trismus prior to 1948 and was advised that the removal of the meniscus would alleviate her problem. The surgical procedure was performed through a horizontal incision at the level of the zygomatic arch.
The patient's jaws were immobilized following this treatment. She stated that her mandible functioned more smoothly and with less pain for about 1 year. Then she began to notice the jaw deviating to the left side, and the pain and grating returned.
Over the following few years she was aware of pain and restriction of jaw movements until finally, 7 years later, the same surgeon suggested a condylectomy to relieve the fibrous ankylosis.
This operation also was performed through a horizontal skin incision, and the mandible was immobilized by intermaxillary traction for 5 weeks postoperatively. The recovery again was uneventful, but several months later the mandible began to deviate to the left, with an abnormal occlusal relationship developing. The patient stated that the left mandibular second and third molars and the left maxillary first, second, and the third molars were extracted to assist in closing an anterior open occlusion which had developed. The mandible became asymmetrical, and occlusal equilibration, followed by gold crown restoration on virtually all posterior teeth, was performed.
During the next 2 years, the patient progressively developed pain and grating in the right mandibular joint. The history for the past 3 years was one of limited motion with pain in the right joint and at times in the left joint.
Clinical Examination--The patient was very pleasant and calmly disposed, with a noticeable asymmetry of the face.
The left side of the mandible was elevated approximately 3/4 inch above the right side. When the patient opened her mouth, the chin deviated to the left 12 mm. The vertical opening was less than 3/4 inch. There was noticeable pain in the patient's facial expression as she attempted to open her jaws. The pain emanated more from the right mandibular joint area.
On palpation, the right condyle would move forward more than would have been expected with the degree of opening that the patient could accomplish. In contrast, the left joint could not be discerned during movements. There was tenderness over the right joint, and clicking was noted.
The intraoral examination showed marked attrition of all the teeth, with gold crowns covering most of the premolars and molars. The left maxillary molars and the left mandibular second and third molars were missing.
Roentgengraphic Examination--A centric profile roentgenogram disclosed a shortening of the condyle area on the left side, producing a 3/4 inch variation between the right and left angles of the mandible.
Mandibular joint films showed a normal-appearing right joint (Fig. 5) with hyper mobility of the right condyle, to the point of near dislocation when the mouth was opened 3/4 inch.
The left joint showed severe degenerative changes. The condyle head was missing, and the neck of the condyle had an osteoarthritic contour with much lipping and spurring of its margins. Its position was opposite the crest of the articular eminence and showed fibro-osseous attachment to the poorly defined, flattened eminence (Fig. 6). There was no change in this position during open or closed occlusal position. The glenoid fossa was empty and appeared flattened, with areas of osteoporosis in its cortical margins.
A posteroanterior roentgenogram of the mandible showed an elevation of the left side of the mandible, which was due to the condylectomy and removal of molar teeth.
Treatment Plan.-- From the history, clinical examination, and x-ray findings, it was apparent that the patient had a fibro-osseous ankylosis of the left joint as a result of the previous meniscectomy and condylectomy (Fig. 7). Because of the unilateral ankylosis, the patient's mandibular movements were accentuated in the right joint, causing a constant strain
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INSERT FIGURES 5, 6, 7, & 8
on the capsule and ligaments, which was manifesting its state of overfunction by eliciting pain.
It was apparent that any attempt at restoring permanent pain-free function in the right mandibular joint would be useless unless normal function could be restored in the nonfunctioning left joint. Since the right joint appeared normal on roentgenographic exami-
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nation, no surgical intervention in this joint was advisable at this time. Restoration of function in the left joint would mean taking three major steps: (1) freeing of the ankylosis; (2) reconstruction of the condyle so that it would be in the glenoid fossa; and (3) creation of a metal barrier to prevent future fusion.
Restoration of the height and position of the condylar neck to its proper position could best be accomplished by means of a vertical osteotomy in the ramus of the mandible and repositioning of the proximal segment of bone so that its superior surface would be in the fossa and its inferior-anterior surface would rest against the cut surface of the ramus. The two segments of the ramus would be secured by a transosseous wire suture, and the mandible would be immobilized for 9 weeks. The fossa-articular eminence would be covered with a cast-Vitallium prosthesis, such as that described previously, held securely by two 5 mm. Vitallium screws (Fig. 8).
Since the patient taught school, it was decided that the surgical procedure should be postponed until summer vacation. Accordingly, on June 19, 1961, the patient was admitted to St. Luke Hospital, and the operation was performed on the following day.
The routine application of Winter arch fracture bars was reinforced by a circumferential wire around the mandibular arch bar and symphysis of the mandible. This prevented the lower arch bar from being pulled superiorly. An acrylic occlusal splint, prepared from previous impressions and models, was designed to open the left posterior occlusion approximately 2 mm.
The vertical osteotomy of the left ramus was performed through a 1 inch skin incision via the Risdon approach. The bone cut was made with a specially adapted bone saw (Christensen variation of the Joseph nasal saw)5 and was directed parallel to the posterior surface of the ramus fro the mandibular notch to just forward of the angle of the mandible.
When the osteotomy was completed, the mandible could be immobilized in the acrylic splint by intermaxillary elastic traction. A sterile gauze dressing was placed over this wound, and the preauricular incision was made with a scalpel to facilitate the arthroplasty and freeing the ankylosis. The skin incision ran vertically in the preauricular fold from the superior to the inferior attachment of the ear. A skin flap was elevated by sharp dissection and sutured forward with three silk sutures. The approach, to the level of the joint, was carried along the cartilage of the ear by sharp dissection. When the lateral rim of the glenoid fossa was exposed, we used sharp and blunt dissection to elevate the attachment of the capsule and masseter muscle until the posterior third of the zygoma and the lateral surface of the articular eminence was exposed.
The condyle stump was now fully exposed and found to be attached by very dense fibro-osseous tissue to the crest of the articular eminence. The glenoid fossa was filled with soft tissue which was reflected by blunt dissection with a periosteal elevator until the entire fossa was exposed.
The fibrous and partially bony attachment of the condyle neck to the eminence was severed by means of a scalpel and sharp chisel. When this had been dissected, the assisting surgeon used a Kelly forceps to grasp the inferior end of the proximal fragment, through the Risdon approach, and retracted this segment of bone inferiorly. This made it possible to free the condyle neck from the eminence and to totally expose the anterior, inferior, and posterior surfaces of the articular eminence and glenoid fossa, so that a suitable surface of bone would be available for the cast-Vitallium prosthesis.
At this point the various cast prostheses, twenty in number, were placed against the bone to check for accuracy of fit. One pattern fit all areas precisely and was now held in position while a hole was drilled for one of the 5 mm. cast-Vitallium implant screws. The hole was drilled slightly smaller in diameter than one of the screws, and the screw was inserted. This held the prosthesis in proper adaptation to all of the surfaces of bone (Fig. 9). The second screw was then placed in a similar fashion.
The proximal segment of bone was now positioned so that the condylar surface was in the most posterior portion of the glenoid fossa of the prosthesis. The inferior margin of this segment of bone was now tilted forward to contact the posterior surface of the osteotomy of the ramus approximately 5/8 inch higher than the inferior margin of the mandible. Because the condyle was tilted posteriorly, there was a v-shaped space between the two fragments-cont'd on page 311
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INSERT FIGURES 9, 10, & 11
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INSERT FIGURES 12 & 13
above the point of contact at the lower margin. A single transosseous steel wire was placed neat the lower margin, where the two bones contacted each other (Fig 10). This was found to immobilize the two fragments adequately, since the jaws were secured by intermaxillary traction.
The preauricular wound was now closed in layers; 3-0 catgut sutures were used on the deeper tissues and 5.0 Dermalon interrupted mattress sutures on the skin margins. The Risdon incision was now closed in a similar fashion. A small piece of Telfa was placed over each wound, and a pressure dressing was used over this.
The patient's recovery was uneventful, and she was discharged on the fourth postoperative day. There was no impairment of any branch of the facial nerve; now was there any disturbances in the mandibular branch of the trigeminal nerve.
The mandible was left immobilized for 9 weeks to allow the bone fragments to unite. At the end of that time the intermaxillary elastic and wire traction was removed. The patient was able to open the jaws 3/8 inch, and the occlusal splint was removed. One week later, under local, anesthesia, the fracture arch bars and circumferential wire were removed.
Over the next few weeks the patient was able to open her jaws 1-1/4 inches. She could create left lateral excursions with ease and excursions to the right to a lesser degree.
The pain which she had noticed in the left mandibular joint subsided after the operation and has not returned. However, the pain in the right joint, which diminished for a few months, slowly increased to the point where further evaluation became necessary.
Pain and grating increased in the right mandibular joint until, in May, 1962, new roentgenograms were taken. These showed a much different picture than those taken in December 1960. The right condyle head was lying forward in the glenoid fossa, with bone-to-bone contact present (Fig. 11). The anterior inclined surface of the glenoid fossa showed early erosion of its cortical surface and a demineralization of the adjacent articular surface of the condyle. It was apparent that a perforation of the disc had occurred.
The left condyle had been totally free of pain since the insertion of the prosthesis one year before, but there had been only a partial return of its normal excursion. The subtotal return of function was probably due to the loss of the attachment, or function, of the external pterygoid muscle as a result of the earlier condylectomy, or it may have been due in part to some fibrous adhesions which occurred during the period of immobilization.
Although the patient's jaw could be forced upon 1-1/2 inches, severe pain in the right joint limited voluntary opening to less than 1 inch. It was decided that a cast-Vitallium glenoid
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INSERT FIGURES 14 & 15
fossa prosthesis should be inserted in the right joint in an attempt to curtail the resorptive processes and to allow the right condyle to move free of pain.
The operation was performed at Huntington Memorial Hospital on Aug. 4, 1962. A few specific variations of technique and observations should be recorded briefly.
The operation was performed through a preauricular incision, and the upper joint space was exposed by careful dissection of the capsular attachments from bone. The erosion of the cortical surface which had been noted on the roentgenograms was now visualized clinically. Adjacent to this same area, the articular disc was seen to have an oval-shaped perforation. The articular surface of the condyle, as seen through the perforation, appeared normal. To facilitate exposure of the glenoid fossa and articular eminence, the capsule, disc, and condyle were retracted inferiorly with a special retractor. When the prosthesis was fully inserted, the mandible was moved with great ease, causing the condyle and disc to slide freely and smoothly over the highly polished surface of the prosthesis.
The patient's postoperative course was most interesting. On the first post-operative day she was able to open her jaw 1-1/4 inches and go into the lateral excursions with ease. There was no grating or limitation of function; nor was there joint pain. On the third postoperative day the patient was discharged from the hospital and was able to chew the hardest foods without pain. Less than one month after the surgical procedure the patient was able to open her jaws 1-1/2 inches, and to date she is totally free of pain (Fig. 12).
Radiographs taken one month after the operation show the normal function of the right condyle against the glenoid fossa prosthesis (Figs. 13 and 14). The posteroanterior mandibular film shows the position of both the right and left joint prostheses in relation to skull and mandible. (Fig. 15).
This patient is most grateful for the relief from pain and the restoration of mobility which the procedure has afforded her.
SUMMARY
This article describes a new technique for creating an anatomic, physiologic, prefabricated, well-tolerated mandibular joint prosthesis for the correction of early and late mandibular joint arthroses.
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I have used this technique six times in the past 15 months (1961 and 1962) and have seen the restoration of normal, pain-free function occur in each case. Although it may be too early to make a complete evaluation, it is believed that this new technique will prove to be of value to many persons suffering from various degrees of mandibular joint arthrosis.
I wish to express my appreciation to Robert F. Chapin for the photographs used in this article.
References
1. Christensen, Robert W.: Chronic Unilateral Dislocation of the Mandibular Joint Treated Surgically by A High Condylectomy, Oral Surg, Oral Med. & Oral Path. 13:12-22, 1960.
2. Schwartz, Laslo: Disorders of the Temporomandibular Joint, Philadelphia, 1959, The W. B. Saunders Company.
3. Thoma, Kurt H.: Oral Surgery, ed. 3, St. Louis, 1958, The C.V. Mosby Company.
4. Christensen, Robert W.: Surgical Correction of Complete Ankylosis of the Mandible, Oral Surg., Oral Med. & Oral Path 8: 1235, 1955.
5. Christensen, Robert W.: Anterior Open-Bite or Retrognathia Corrected by a Vertical Sliding Osteotomy of the Ramus, With or Without a Bone Graft; an Improved Technique, Oral Surg., Oral Med. & Oral Path 13: 1409-1422, 1960.
175 So. El Molino Ave.
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The Correction of Mandibular Ankylosis by Arthroplasty
and the Insertion of a Cast Vitallium Glenoid Fossa
A New Technique
A Preliminary Report of Three Cases
Robert W. Christensen, D.D.S. t
Reprinted From THE AMERICAN JOURNAL OF ORTHOPEDICS, JANUARY, 1963
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Introduction
This article will be limited to a discussion of intra-articular ankylosis of the mandible and will discuss a new method of creating a barrier against the recurrence of this problem.
Ankylosis of the mandible can be fibrous, fibro-osseous, or osseous and can be initiated by a variety of etiologic factors. Such factors are birth trauma, hemarthrosis, infections, fractures of the condyle, tumors, rheumatoid or osteoarthritis, anatomic variation in the condyle or articular eminence, or following mandibular joint surgery--especially menisectomy. It might be well to state my belief that degenerative changes which occur in some of these joints may occur in jaws with normal occlusion. An imbalance in the neuromuscular activity of some patients is undoubtedly a predisposing factor in the development of the forces which lead to joint degeneration which in turn, may lead to fibrous ankylosis.1
In the cases to be presented, we have more readily recognized factors which have preceded the ankylosis.
In the first case, we have a young lady who had a unilateral menisectomy for chronic mandibular joint pain and who developed unilateral fibro-osseous ankylosis--which was later relieved by condylectomy but was again followed by ankylosis.
The second case is one in which a 46 year old man had generalized rheumatoid arthritis and slowly developed bilateral osseous ankylosis of the mandible.
The third case is that of a 57 year old woman who had a long history of left mandibular joint degeneration with negligible mobility. The attrition of the disc was such that a high condylectomy did not relieve her pain and immobility of the joint soon recurred.
Generally speaking, the fibrous or osseous ankylosis requires the same type of treatment with, perhaps, slight variations in technique.
Dr. Laszlo Schwartz states, "Ankylosis is highly disabling and when ankylosis has developed any form of conservative treatment is useless. Operation is the only possible way of helping the patient."2
Over a period of years, previous authors have advocated either no treatment or high condylectomy for fibrous ankylosis and osteoarthrotomy for osseous ankylosis.
The disability caused by either type of fusion is one of pain and degree of limitation. It would seem that a more uniform approach to both types of ankylosis would be welcome and that every effort should be made to restore a reasonably anatomic joint surface.
In the previous reported articles on osteoarthrotomy of the mandibular joint, the procedures have varied from placing nothing in the new joint space to the use of fascia, muscle, cartilage, plastic, or metal. Good results have been reported with each variety of osteoarthrotomy. In a case I reported in 1955, I placed no new material between the two bone surfaces and the patient has done well for nine years.3
Ideally, it would seem, a rigid mechanical barrier of anatomical shape would be most valuable; and for that reason I have attempted to devise a metal prosthesis which is anatomic, creates a permanent barrier and is well tolerated. The problem that has faced oral surgeons who might have wished for an anatomic prosthesis is how does one know the shape of the particular bone prior to surgery? Most attempts have been focused on attempting to restore a lost condyle or to cover the condylar stump with a non-anatomic barrier. The most promising prosthesis from a strictly bio-mechanical point of view would be to place the prosthesis against the base of the skull where unusual lateral pressures would not tend to loosen it.
It occurred to me, that in the case of a fibrous ankylosis, where it is possible to define the glenoid fossa and articular eminence both radiographically and clinically, that we should be able to cover this surface with a thin, anatomic cast vitallium prosthesis. With this premise I decided to make castings to cover the glenoid fossa, articular eminence and adjacent zygomatic process on 20 skulls (Fig. 1). The castings were made .022 inch thick and were perforated on the surface covering the zygoma and lateral articular eminence with numerous holes for the 5 mm. cast Vitallium implant screws, which would-con't on page 316
t-Associate Editor of the Journal of Oral Surgery, Oral Medicine and Oral Pathology. Secretary of the Southern California Association of Oral Surgeons. 175 So. El Molino Ave., Pasadena, Calif.
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INSERT FIGURES 1 & 2
be used for anchorage (Fig. 2). The articular surface was highly polished, while other surfaces and margins were sandblasted. This thickness of Vitallium had some resiliency and could be formed lightly with pliers to allow for last minute variations in contour. The borders were extended as shown in the photograph, to include most of the glenoid fossa, articular eminence, and lateral surfaces of both on to the lateral aspect of the zygomatic process of the temporal bone.
In the preparation of this type of prosthesis, for any given case, it is important to have accurate X-rays of the joint to give as much information as possible of the anatomic shape of the joint. In cases of osseous ankylosis, the procedure needs to be varied slightly because of the loss of the normal anatomic contour of the joint. In this case, it is necessary to create an osteotomy below the normal glenoid fossa and attempt to make it at the level of the articular eminence. In so doing, one can be sure not to perforate the cranial cavity. In the past, the suggestion has been made to remove, if possible, the condyle head or at least a 1 cm segment of bone. This has been necessary, where no mechanical barrier has been placed in the area. In some cases where a large segment of bone has been removed, the powerful elevator muscles have tended to close the bone gap, thus allowing a refusion to occur and at times an open bite.
By using several skulls and filling the glenoid fossa with modeling compound or plasticene, it is possible to make a pattern which will lay on the external surface of the condyle fossa, eminence and to decide just how the cut should be made. If this small pattern is fixed with screws to the bone, then one can follow the exact curvature of the osteotomy which will be most suited. By making the final prosthesis in the shape of the previously mentioned glenoid fossa and articular eminence (only following the contour of the pattern), one can be sure that it will slide into place following the osteotomy. In this case, the condylar head can be left in the fossa and the prosthesis can be attached to it. This then decreases the hazards attached to the removal of the condyle head; and in cases where this would be impossible, it removes the need for doing it. The thickness of the prosthesis can be from .014 to .022 inch so that varying degrees of adaptability can be selected. For this purpose, these thicknesses give ample rigidity and act as a permanent barrier to reankylosis of the joint. It is conceivable that Tantalum, in about 0.19 inch thickness, could be fabricated at the time of surgery and would also be useful. I have preferred cast Vitallium for its rigidness and also for the fact that the articular surface can be highly polished, thus giving it a smooth surface for the condyle to function against.
In all cases of ankylosis of one or both mandibular joints it is wise to correct the problem surgically since, over a period of time, fibrosis may occur in the elevator muscles, thus causing an additional type of restriction which is difficult to relieve.
CASE REPORTS
CASE 1: Sister L., a 35 year old Catholic Nun, was referred to my office on December 5, 1960, for consultation regarding pain in her right mandibular joint, which was intermittant, dull and present for two to three years.
Past History: The patient gave a history of having a left mandibular joint menisectomy in 1948 by a surgeon in another city. She stated she had joint pain, cracking, and periods of trismus prior to 1948, and was advised that the removal of the meniscus would alleviate her problem. The surgery was done through a horizontal incision at the level of the zygomatic arch.
The patient's jaws were immobilized following this treatment. She stated that her mandible functioned more smoothly and with less pain for about one year, and then she began to notice her jaw deviate to the left side, and pain and grating returned.
Over the following few years, she was aware of the pain and restriction of the jaw movements until finally, seven years later, the same surgeon suggested a condylectomy to relieve the fibrous ankylosis.
Again, this was done through a horizontal skin incision, and the mandible was immobilized by intermaxil-
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INSERT FIGURES 3, 4, & 5
lary traction for five weeks post surgically. Her recovery again, was uneventful, until several months later, when her mandible began to deviate to the left with an abnormal occlusal relationship developing. She state her left mandibular second and third molars and left maxillary first, second, and third molars were extracted to assist in closing an anterior open occlusion, which had developed. Her mandible became asymmetrical, and occlusal equilibration followed by gold crown restoration, on virtually all posterior teeth, was accomplished next.
Her mandible remained the same, until two years later, when she began to develop pain and granting in her right mandibular joint. Her course for the past three years had been one of limited motion with pain in her right and at times, left joints.
Clinical Examination: The patient was a very pleasant and calmly disposed Catholic Sister with a noticeable asymmetry of the face.
The left side of the mandible was elevated approximately 3/4 inch above the right side. When the patient opened her mouth, the chin deviated to the left 12 mm. Her vertical amount of opening was less than 3/4 inch. There was a noticeable pain in her expression as she attempted to open her jaws. The pain apparently eminated more from her right mandibular joint area.
By palpatation, the right condyle would move forward more than expected with the degree of opening she could accomplish. In contrast, the left joint could not be discerned during movements. There was tenderness over the right joint and clicking was noted.
The intra-oral examination showed marked attrition of all of the teeth with gold crowns covering most of the bicuspids and molars. She was missing the left maxillary molars and left mandibular second and third molars.
Roentgenographic Examination: Centric profile roentgenogram: disclosed a shortening of the condyle area on the patient's left side, so that there was 3/4 inch variation between the right and left angles of the mandible.
Mandibular joint films: showed a normal appearing right joints with hypermobility of the right condyle to the point of near dislocation while opening 3/4 inch (Fig. 3). The left joint showed severe degenerative changes. The condylar head was missing, and the neck of the condyle had an osteoarthritic contour with much lipping and spurring of its margins. Its position was opposite the crest of the articular eminence and showed fibro-osseous attachment to the poorly defined, flattened eminence (Fig. 4).There was no change in this position during open or occlusal position. The glenoid fossa was empty and appeared flatter and with areas of osteoporsis in its cortical margins.
P-A Mandible roentgenogram: showed an elevation of the left side of the mandible due to the condylectomy and removal of molar teeth.
Treatment Plan: From the history, clinical examination, and X-ray findings it was apparent that the patient had a fibro-osseous ankylosis of the left joint due to the previous meniscetomy and condylectomy (Fig. 5). Because of the unilateral ankylosis, the patient's mandibular movements were accentuated in the right joint causing a constant strain on the capsule and ligaments which was painful. It was apparent that any attempt toward restoring permanent pain-free function in the right mandibular joint would be useless unless normal function could be established in the left joint. To restore this would mean taking three major steps. First, free the ankylosis; second, reconstruct the condyle so it would be in the glenoid fossa; third create a metal barrier to prevent future fusion of the mandible to the skull.
To restore the height and position of the condyle neck to its proper position could best be accomplished by doing a vertical osteotomy of the ramus of the mandible and repositioning the proximal segment of bone so its superior surface would be in the fossa and its inferior-anterior surface would rest against the cut surface of the ramus. The two segments of the ramus would be secured by a transosseous wire suture, while the mandible would be immobilized for nine weeks. The fossa-articular eminence would be covered with a cast Vitallium prosthesis as described above and held securely by two 5 mm. Vitallium screws (Fig. 6)
Since the patient taught school, it was decided to wait for summer vacation to perform the surgery. In the interim, the right mandibular joint was injected with hy-cont'd on page 318
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The National Institute of Dental Research (NIDR) invites applications for the support of one or more Orofacial Pain Research Centers. The overall purpose of these centers will be to support both basic and clinical research to expand knowledge concerning the etiology, treatment and mechanisms underlying orofacial pain. The ultimate aim of such research will be to establish a sound scientific foundation permitting improved diagnosis, treatment and prevention of orofacial pain.
BACKGROUND-Preventing and controlling orofacial pain remains a central concern of the dental profession, and a major concern of the public which dentistry seeks to serve. The significance of orofacial pain, both to the health professions and the public, stems in part from a simple biological fact. The face and mouth possess a dense, rich supply of nerves, which makes them exquisitely sensitive and responsive to painful stimuli.
Both acute and chronic orofacial pain constitute major clinical problems which can challenge the limits of our current scientific knowledge. Acute dental pain may occur as a manifestation of oral disease or pathology, as, for example, when deep carious lesions expose the dental pulp or when infection occurs in oral soft tissues. In such cases, pain serves a protective, adaptive function through signaling the existence of tissue damage or injury and impelling the individual to seek treatment. Acute post-surgical pain can occur following procedures such as tooth extraction or periodontal surgery. Acute dental pain can also be associated with other dental procedures, despite the fact that various technological innovations in dentistry (such as the high speed drill) have substantially reduced pain-eliciting aspects of many dental procedures. Nevertheless, the expectation of acute dental pain associated with dental care still deters many Americans from seeking needed dental care. An estimated 20 million Americans admit to being so highly fearful of dental treatment that they forgo or delay needed care. Only approximately half of the American public seek dental care. While many factors combine to produce this low level of dental utilization, concerns regarding the effectiveness and safety of dental pain management clearly constitute one barrier to appropriate utilization of preventative and therapeutic dental services.
Chronic orofacial pain disorders also present a difficult and urgent area for study. Chronic pain problems by definition persist over a long period of time, usually a minimum of several months. In contrast with acute pain, chronic pain often appears to serve no adaptive or protective function. It can have devastating negative effects on the individual and the individual's family, including depression, impairments in social or vocational functioning and even in some cases suicide. Direct and indirect costs associated with all chronic pain problems have been estimated to total over $50 billion per year
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in the United States. Pain clinic surveys suggest that as many as 20-25% of chronic pain problems involve the orofacial region.
Major advances in pain research have occurred over the past decade. These advances have emerged from the efforts of investigators representing a variety of disciplines, including neuroanatomy, neurochemistry, neurophysiology, pharmacology, psychology, psychophysiology, anesthesiology, neurology, neurosurgery, psychiatry, and pathosphysiology. An understanding concerning how pain signals are encoded and transmitted within the nervous system is now emerging. Neurochemicals in the brain and spinal cord have been isolated and found to operate as pain-blocking agents in pain-inhibited pathways. New insights on anatomical, physiological, and behavioral dimensions of pain modulation have led to new pain treatment procedures such as transcutaneous electrical nerve stimulation and stimulation-produced analgesia. Improved measures of both the sensory and affective dimensions of human pain have been developed. Nevertheless, many questions remain to be answered both regarding the mechanisms underlying the transmission and modulation of acute and chronic pain, and regarding many aspects of orofacial pain diagnosis and treatment.
Recent years have brought a great surge of clinical interest within dentistry in the temporomandibular joint (TMJ), an interest resulting from increased numbers of individuals seeking treatment for a variety of pain and dysfunction problems associated with this joint. Such individuals commonly show a combination of findings which include muscle pain or tenderness, localized pain, limitations in jaw openings, and various types of sounds or "clicking" in the TM joint. Epidemiologic studies suggest that 10-20% of the population show one of more of these findings. Because of controversies over diagnostic criteria, however, the exact prevalence of TMJ disorders remain unclear. It seems likely, however, that TMJ dysfunction and pain constitute important problems for many Americans.
The NIDR recognizes the need for an improved and expanded interdisciplinary orofacial pain research effort. It is both scientifically feasible and necessary to stimulate additional effort in this area of demonstrable research need. The Center mechanism is well suited to fostering an expanded orofacial pain research effort. Integration of basic and clinical orofacial pain research within the Centers is expected to help stimulate the translation of new basic research findings into clinically-relevant hypotheses and improved, innovative approaches to orofacial pain diagnosis or treatment. Such Centers are also expected to provide an environment fostering basic orofacial pain research.
OBJECTIVES-The overall objective of the Orofacial Pain Research Centers will be to accelerate the development and synthesis of knowledge concerning acute dental and chronic orofacial pain, with the ultimate aim of developing a scientific foundation for optimally safe and effective prevention and control of orofacial pain.
The research emphasis of specific Orofacial Center proposals may vary depending on the expertise, resources, and interests represented within the applicant institution. However, in order to be responsive to the intent of this RFA, the research proposal for Center activity mush include both basic
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and clinical research. Studies related to the basic biological mechanisms involved in orofacial pain are expected to comprise a significant proportion of the research effort. A Center application comprised mostly of basic neurological studies without direct relevance to orofacial pain is beyond the scope of this RFA and would be more appropriate to the interests of the NINCDS.
It is anticipated that each Center will direct some research effort toward studies relevant to chronic orofacial pain. The increasing clinical demands placed upon dentistry for diagnosis and treatment of chronic orofacial pain disorders and the paucity of relevant basic or clinical information provide the context for this requirement. Determining the specific proportion of research effort devoted to chronic orofacial pain studies remains the applicant's prerogative.
Research objectives to be addressed in the Orofacial Pain Research Centers may include, but are not limited to the following:
1. Studies to identify and elucidate the biological mechanism involved in oro-
facial pain transmission and modulation.
2. Research on CNS mechanism involved in pathological pain.
3. Neuropharmacological studies of agents for use in the control of chronic
orofacial pain or acute dental pain.
4. Small scale epidemiological studies assisting toward the identification of the incidence and distribution of chronic orofacial pain.
5. Studies of factors influencing human pain perception, as well as studies developing improved behavioral and psychophysiological means of pain
assessment.
6. Studies of the basic and clinical aspects of acute dental pain, including
post-surgical pain
7. Basic and clinical studies of chronic pain associated with the temporo-
mandibular joint or myofascial pain, or orofacial pain syndromes such as tic douloureux, atypical facial pain, and post-herpetic neuralgia.
8. Experimental or clinical studies that clarify the association between orofacial
motor dysfunction and orofacial pain.
9. Studies to develop improved, effective, diagnostic and treatment procedures
applicable to acute dental pain and to chronic orofacial pain condition.
MECHANISM AND LENGTH OF SUPPORT
The Centers will be supported by the research grant mechanism for a period of five years, with funding projected to start on or before July 1, 1986.
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Subsequent support will be contingent upon program needs and the Center's perfor-mance, as determined by peer review. While funds have been allocated for this purpose in the NIDR plans for FY '86 and subsequent years, awards are contingent upon the availability of funds. All policies and requirements which govern the research grant programs of the PHS, including cost sharing, will apply to grants made as a result of responses to this invitation.
REVIEW PROCEDURES AND CRITERIA
The applications will be reviewed by a Special Review Committee to be convened by NIDR's Scientific Review Branch. Scientific review may include a site visit. Secondary reviews will be by the National Advisory Dental Council.
Major factors to be considered in the evaluation of applications will include:
1. The scientific merit of each project including its originality and feasibility, the
soundness of the methodology proposed, and the competence of the in-
vestigators.
2. The extent to which the Center will promote advances in orofacial pain re-
search which could not be achieved or, which would be achieved more slowly, if the component projects were funded separately.
3. The availability of basic or clinical researchers qualified to conduct the
proposed research.
4. The adequacy of laboratory and clinical facilities and the availability of
appropriate patient populations.
5. The scientific and administrative qualifications and experience of the director
and his/her availability to provide effective leadership.
6. Adequacy of plans for establishing and maintaining the Center, for monitoring
research for encouraging scientifically productive interactions between basic and clinical researchers, and for reviewing changes in research directions.
7. Institutional commitment to the Center both in terms of financial and related resource allocations.
8. The technical merit and justification for core resources requested.
9. Appropriateness of budget justifications.
Applicants should attempt to develop a unique program which is complementary
to, rather than duplicative of, ongoing research. The institution must be willing to make a commitment of resources and staff to ensure the development, operation and function of the proposed Center. Should no application meeting these criteria and judged to show a high level of scientific merit be received, no award will be made and this RFA may be readvertised.
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CENTER CHARACTERISTICS
The Orofacial Pain Research Centers will be identifiable units within a larger institution; eligibility is limited to domestic institutions. The Centers will consist of a cluster of related projects, some of which may be single investigator projects while others will involve interdisciplinary team approaches.
The Center director will be responsible for scientific and administrative leadership. A committee, consisting of staff members and other expert consultants, who are not members of the Center staff, would be expected to advise the director on the merits of new projects as well as review the progress of existing studies. It is anticipated that the Center will encourage collaboration with researchers from other departments or research units conducting research relevant to orofacial pain. It is also anticipated that the Center will provide a training environment for young and new investigators. Funds may be used to support pilot or exploratory studies.
ADMINISTRATIVE ITEMS AND COST
Core resources such as computer service and equipment to be shared by the investi-gators can be provided. Funds can be used for equipment, supplies, consultation ser-vices, travel, publications costs and for salaries of professional, technical, or administrative support staff. Funds will not be used for new construction, major renovations of facilities or costs associated with delivering oral health services than those directly related to the research program.
Each scientist is expected to obtain independent research support from sources other than the Center grant during the award period, thereby releasing funds to attract other scientist to enter the Center's interdisciplinary research program. Applicants may request up to $300,000 in direct costs for the first year, with appropriate increases in subsequent years. Funding is anticipated for a five year project period with a possibility of renewal. This proposed duration should provide a more stable environment than is often encountered when investigators are supported entirely by individual research project grants. Site visits to review the performance at the Center and provide guidance will be conducted periodically by the NIDR staff and consultants.
METHOD OF APPLICATION
It is suggested that prospective applicants submit a letter of intent (limited to two pages) by April 30, 1985 to Dr. Patricia S. Bryant at the address indicated below. Applicants are also encouraged to contact Dr. Bryant for additional information.
The suggested letter of intent should summarize the Center's objectives, a list of proposed component research projects and a summary of relevant ongoing research. This is expected to assist respondents assure that their applications are responsive; it will also assist staff in planning for timely review of applications. The letter of intent is not binding nor is it a prerequisite for acceptance of applications. Applications which are judged nonresponsive to this RFA will be returned to the applicant, as will applications received after June 15, 1985.
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Applications should be prepared on Form PHS 398, (Rev 5/82). Application for PHS Grant, which can be obtained from the Division of Research Grants, NIH, or from the instruction's application control office. The First (face) page of the application and the outside of the mailing package should be labeled RESPONSE TO RFA-85-DE-1.The instructions accompanying Form 398 should be followed as far as possible but some modifications will be necessary. For example, a new Table of Contents should be prepared giving page numbers for all items in the application. Each component project should be identified by number and investigator. Separate detailed budgets for the first 12 month period for the entire Center, core resources and component projects should be prepared. Consolidated budgets for all years of support should be included for the entire Center and for the separate component projects. Funds may be requested for professional technical, and administrative personnel, core resources, equipment, supplies, minor renovations, consultant services, travel, publication costs, and patient cost directly related to the research. Detailed justification of the budget requests will be required. Under Section 2, Research Plans, describe the goals of the Center and explain how the core resources and each component project will contribute to achieving those goals. Describe the administrative structure and define the responsibilities of the Director, advisory groups, and individual investigators. Describe the relationship of all existing institutional research projects to the Center. Describe the core unit and explain how it will relate to the projects that will utilize its resources. Each component project should be presented as if it were a research project grant application, that is, the instruction pages 15-18 of Form 398 should be followed. A page (Abstract) Form 398 should be completed for the core resources, each component project and the entire application. The receipt date for an original and four copies of the complete application is on or before June 15, 1985. Applications should be sent to:
Division of Research Grants
National Institute of Health
Westwood Building-Room 240
5333 Westbard Avenue
Bethesda MD 20205
In addition, two copies should be sent under separate cover to:
Patricia S. Bryant, Ph.D.
Health Scientist Administrator
Craniofacial Anomalies, Pain Control and Behavioral Research Program
National Institute of Dental Research
Westwood Building, Room 506
5333 Westbard Avenue
Bethesda MD 20205
301 - 496-7807
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APPENDIX 6. --FEDERAL REGISTER ANNOUNCEMENT FOR TMJ IMPLANTS

Federal Register / Vol. 57, No 182 / Friday, September 18, 1992/ Proposed Rules
above) written comments regarding this proposal. Two copies of any comments are to be submitted, except that individuals may submit one copy. Comments are to be identified with the name of the device and the docket number found in brackets in the heading of this document. Received comments may be seen in the office above between 9 a.m. and 4 p.m., Monday through Friday.
LIST OF SUBJECTS IN 21 CFR PART 884
Blood, Medical devices, Packaging, and containers.
Therefore, under the Federal Food, Drug, and Cosmetic Act and under authority delegated to the Commissioner of Food and Drugs, it is proposed that 21 CFR part 884, be amended as follows:
PART 864-HEMATOLOGY AND PATHOLOGY DEVICES
1. The authority citation for 21: CFR part 864 continues to read as follows:
Authority: Secs. 501,510,513,515,520,701 of the Federal Food, Drug, and Cosmetic Act (21 U.S.C. 351, 360, 360c, 368e, 370f, 371).
2. Section 864.5680 is amended by revising paragraph (b) to read as follows:
S. 864.5680 Automated rest illegible
(b) Classification: Class M (special controls).
Dated August 6, 1992
Michael R. Taylor
Deputy Commissioner for Policy.
{FR Doc. 92-22820 Filed 9-17-92 8:45 a.m.}
Billing Code 4100-01-01
________________________________________________________________________ 21 CFR Part 872
[Docket no 9426-0281]
Medical Devices; Classification of Temporomandibular Joint Implants
Agency: Food and Drug Administration, HHS.
Action: Proposed rule.
________________________________________________________________________ Summary: The Food and Drug Administrations (FDA) is proposing to classify cer- tain temporomandibular joint (TMJ) implants into class III (premarket approval). Based upon the recommendations of FDA's Dental Device Classification Panel, the agency published a final regulatory classifying 110 preamendments dental devices
on August 12, 1987 (52 FR 30882 and 30887). The TMJ prosthesis were inadver-
titanly omitted for classification by the Dental Device Classification Panel and the
Agency. Based upon the recommendations of the Dental Products Panel, FDA is now proposing to classify certain TMJ prostheses, including the intrauricular disc prostheses (the interpositional implant), the mandibular condyle prosthesis, and the glenoid fossa prosthesis into class III. After considering public comments on the proposed classification, FDA will publish a final regulation classifying the devices.
These actions are being taken under the Federal Food, Drug and Cosmetic Act (the act), as emended by the Medical Device Amendments of 1976 (the amendments)
and the Safe Medical Devices Act of 1990 (the SMDA).
Dates: Written comments by November 17, 1992. The Commissioner of Food and Drugs proposes that any final regulations based on his proposal, become effective 30 days after the date of its publication in the Federal Register.
Addresses: Submit written comments to the Dockets Management Branch (HFA-
305), Food and Drug Administrations, rm 1-23,12420 Parklawn Drive, Rockville, MD
20857
For further Information Contact: Joseph M. Sheenan, Center for Devices and Radiological Health (HFZ-84), Food and Drug Administration 12720 Twinbrook Pkwy
Rockville, MD 20857 301-443-4874.
Supplementary Information:
I. Background-The act, as amended by the amendments (Pub 1-94-295) and the
SMDA (Pub I-102-829), established a comprehensive system for the regulation of
medical devices intended for human use. Section 503 of the act (23U.S.C. 360c) es-
tablished three categories (classes) of devices, depending on the regulatory controls
needed to provide reasonable assurance of safety and effectiveness. The three cata-
gories of devices as follows are Class I, general controls, class II special controls,
and class III premarket approval.
Devices that were in commercial distribution before May 28, 1976 (the date of en-
actment of the amendments) are classified under 21 U.S.C. 360c after FDA has received a recommendation from a device classifications panel (an FDA advisory
committee): (2) published this panel's recommendations for comment, along with a
proposed regulations classifying the device and (3) published a final regulation
classifying the device. A device that is first offered in commercial distribution after May 28, 1976, and is substantially equivalent to device classified under this scheme, is also classified into the same class as the device to which it is substantially equivalent.
A device that was not in commercial distribution prior to May 28, 1976, and that is
not substantially equivalent to a preamendment device, is classified by statute in- to class III without any FDA rulemaking proceedings. The agency determines
whether new devices are substantially equivalent to previously offered devices by means of the premarket notification procedure in section 510(k) of the act (21 U.S.C. 360k) and part 807 of the regulations (21 CFR part 807).
Based upon the recommendations of FDA's Dental Device Classification Panel, the
agency published a final regulation classifying 110 preamendment dental devices on August 12, 1987 (52 FR 30882 at 30097). The TMJ implants were inadvertently
omitted from the dental devices considered for classification by the Dental Device Classification Panel and the agency. Based upon the recommendations of the
Dental Products Panel, following its April 12, 1988, meeting, FDA is now proposing
to classify the interarticular disc prosthesis (the interpositional implant), the mandibular condylar prosthesis, and the glenoid fossa prosthesis into class III.
The effects of classifying a device into class III is to require each manufacturer of
the device to submit to FDA a premarket approval application (PMA) by a date to be
set in the future regulation under section 515(b) of the act (21 U.S.C.360e(b)). Each
application must include sufficient valid scientific evidence to provide reasonable
insurance that the device is safe and effective under the conditions if use prescribed,
recommended, or suggested in its proposed labeling-PMA's for class III preamend-
ments devices must be submitted within 30 months after their final classification, or 90 days after the agency publishes a final regulation under 21 U.S.C. 360c(b) re-
quiring PMA's for the device, whichever is later.
FDA is also advising interested persons that the agency lacks evidence that the total TMJ prosthesis was legally in commercial distribution in the United States on
or before May 28, 1976. FDA invites comment on this issue. If the agency concludes that the total temporomandibular prosthesis is not a preamendments device, it is automatically classified into class III and would require an approved PMA before it could be marketed. In accordance with section 501(f) (B0(i) of the act [21 U.S.C. 361 (f)(1)(b)(i), the device would therefore be adulterated if its commercial distribution were to
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continue without such approval in effect. Rather than delay classification of this device, however, in the event FDA includes that it is, in fact, a preamendments device, the agency is now proposing to classify the device into class III, based upon
the recommendations of the Dental Products Panel.
FDA advices manufacturers of the devices being classified that, if the devices
are classified into class III, the agency intends to require PMA's to be filed for these devices at the earliest date allowed under the statute. Therefore, PMA's (or approved
investigational device exemptions) would be required for these devices on the last
day of the 30th month following final classification into class III.
It is the agency's position that the SMDA does not require the agency to obtain
new classification recommendations from a panel that had made classification recommendations under the government standards. In addition, the agency believes that, in light of the reasons for which the Dental Products Panel recommended that
the TMJ devices be classified into class III, its recommendations of class III would be the same under the new standards. FDA's decision concerning classifications of these devices will be made under the standards set forth in the act as amended by the SMDA.
II. The Dental Products Panel Recommendations
A. Total TMJ Prosthesis
The Dental Products Panel, an FDA advisory committee, made the following recommendations regarding the classification of the total TMJ prothesis.
1. Identification: A total TMJ prosthesis is a device that is intended to be implanted in the human jaw to replace the mandibular condyle and augment the glenoid fossa to functionally reconstruct the temporomandibular joint.
2. Recommended classification: Class III (premarket approval). The Panel recommended that premarket approval of the total TMJ prosthesis be low priority.
3. Summary of reasons for recommendations: The Dental Products Panel
recommended that the total TMJ prosthesis be classified into class III because the
Panel believed that premarket approval is necessary to provide reasonable assurances of the safety and effectiveness of the device. The Dental Products Panel
also believed that the device presents a potential unreasonable risk to health and
that insufficient information exists to determine that general controls are sufficient
to provide reasonable assurance of the safety and effectiveness of the device. The
Dental Products Panel believed that a performance standard would not provide reasonable assurance of the safety and effectiveness of the device and that there is not sufficient information to establish such a standard. Therefore, the device should
be subject to premarket approval to ensure that each manufacturer of this device
develops sufficient information to provide reasonable assurance that it is safe and effective.
4. Summary of data on which the recommendations is based: The Dental Pro-
ducts Panel based its recommendations on the Panel members' personal knowledge of, and clinical experience with, the device and presentations by Panel
members and interested parties (Ref. 1).
5. Risks to health: The following risks are associated with the total TMJ
prosthesis: (a) Implant loosening or displacement. The screws used to anchor the
implant may loosen, resulting in implant loosening or displacement, causing changes in bite, difficulty in chewing, limited joint function and unpredictable wear on implant components (Refs. 2 through 5; (b) Erosion or resorption of the glenoid
fossa. Implant breakdown may result in erosion or resorption of the glenoid fossa.
The erosion or resorption may result in intense pain, changes in bite, difficulty in
chewing and limited total joint function(refs. 2 through 5); (c) Foreign body reaction. Implant deterioration and migration may result to a foreign body reaction charac-
terized by multinucleated giant cells (Refs. 2 through 5); (d) Infection. If the implant
cannot be properly sterilized, infection may result; (e) Loss of implant integrity. If
the implant materials are unable to withstand mechanical loading, the implant can
be torn, worn, perforated, delaminated, fragmented, fatigued, or fractured, resulting in failure of the device to function properly (Refs. 2 through 5); (f) Chronic pain. Degenerative changes within the articular surfaces and components of the temporo-
mandibular joint due to implant breakdown may result in chronic pain (Refs. 2
through 5); (g) Corrosion. If the implant materials are subject to corrosion, toxic
elements may migrate to various parts of the body; (h) Changes to the contralateral
joint. Unilateral placement of the implant may result in deleterious effects to the
contralateral joint; and (i) Malocclusion. Placement of the device may product an
improper occlusal relationship.
FDA agrees with the Dental Products Panel's classification recommendation and is proposing that the total TMJ prosthesis be classified into class III (premarket
approval). FDA does not concur with the Dental Products Panel's recommendations
that premarket approval of the total TMJ prostheses be low priority. FDA believes
that insufficient information exists to identify the proper materials or design for the
total TMJ prosthesis. Therefore, FDA is proposing that premarket approval of the total TMJ prostheses be high priority.
The act requires the agency to classify into class III a device that presents a
potential unreasonable risk of illness or injury unless it determines that premarket approval is not necessary to provide reasonable assurance of the safety and effec-
tiveness of the device. In this case, the agency has determined that premarket approval is necessary for this device. FDA believes that the device presents a po-
tential unreasonable risk of illness or injury to the patient if there are not adequate
data to ensure the safe and effectiveness use of the device. The agency believes
that general controls, either alone or in combination with the special controls ap-
plicable to class II devices, are insufficient to provide reasonable assurance of the
safety and effectiveness of the device.
B. Glenoid Fossa Prosthesis
The Dental Products Panel did not make a recommendation respecting classifi-
cation of the glenoid fossa prosthesis, but noted that the implanted glenoid fossa
should not be used with a naturally occurring mandibular condyle. FDA has deter-
mined, however, that the implanted glenoid fossa has been used to replace a naturally occurring glenoid fossa. Therefore, FDA makes the following proposal regarding the glenoid fossa prosthesis:
1. Identification: A glenoid fossa prosthesis is a device that is intended to be im-
planted in the temporomandibular joint to augment a glenoid fossa and provide an articulation surface for the head of a naturally occurring mandibular condyle.
2. Recommended classification: Class III (premarket approval). FDA proposes
that premarket approval of the glenoid fossa prosthesis be high priority.
3. Summary of reasons for proposal: FDA proposes that the glenoid fossa prosthesis be classified into class III.
The act requires the agency to classify into class III a device that presents a
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potential unreasonable risk of illness or injury unless it determines that premarket approval is not necessary to provide reasonable assurance of the safety and effectiveness of the device. In this case, the agency has determined that premarket approval is necessary for this device. FDA believes that the device presents a potential unreasonable risk of illness or injury to the patient if there are not adequate data to ensure the safe and effective use of the device. The agency believes that general controls, either alone or in combination with the special controls applicable to class II devices, are insufficient to provide reasonable assurance of the safety and effectiveness of the device. Therefore, the device should be subject to premarket approval to ensure that each manufacturer of this device develops sufficient information to provide reasonable assurance that it is safe and effective.
4. Summary on data on which the proposal is based: FDA is basing its proposal on the Dental Products Panel members' personal knowledge of and clinical experience with the device and presentations by Panel members and interested parties. (Ref 1).
5. Risks to health: The following risks are associated with the glenoid fossa prosthesis: (a) Implant loosening or displacement. The screws used to anchor the implant may loosen, resulting in implant loosening, or displacement causing changes in bite, difficulty in chewing, limited joint function and unpredictable wear on implant components (Refs.2 through 5); (b) Degenerative changes in the material articulating surfaces. Implant breakdown may result in erosion or resorption of the head of the mandibular condyle or the glenoid fossa. The erosion or resorption may result in intense pain, changes in bite, difficulty in chewing, limited joint function, and perforation into the middle cranial fossa (Refs 2 through 5); (c) Foreign body reaction. Implant deterioration and migration may result in a foreign body reaction characterized by multinucleated giant cells (Refs 2 through 5); (d) Infection. If the implant cannot be properly sterilized, infection may result; (e) Loss of implant integrity. If the implant materials are unable to withstand mechanical loading the implant can be torn, worn, perforated, delaminated, fragmented, fatigued, or fractured, resulting in failure of the device to function properly (Refs. 2 through 5); (f) Corrosion. If the implant materials are subject to corrosion, toxic elements may migrate to various parts of the body; (g) Chronic pain. Degenerative changes within the articular surface and components of the temporomandibular joint due to implant breakdown may result in chronic pain (Refs. 2 through 5); (h) Changes to the contralateral joint. Unilateral placement of the implant may result in deteriorating effects to the contralateral joint; (i) Malocclusion. Placement of the device may produce an improper occlusal relationship.
C. Mandibular Condyle Prosthesis
The Dental Products Panel did not make a recommendation regarding the classification of the mandibular condyle prosthesis, but noted that the implanted mandibular condyle should not be used with a naturally occurring glenoid fossa. FDA has determined, however, that the implanted mandibular condyle has been used to replace a naturally occurring mandibular condyle. Therefore, FDA makes the following proposal regarding the mandibular condyle prosthesis:
1. Identification: A mandibular condyle prosthesis is a device that is intended to be implanted in the human jaw to replace the mandibular condyle and to articulate within a naturally occurring glenoid fossa.
2. Recommended classification: Class III (premarket approval). FDA proposes that premarket approval of the mandibular condyle joint prosthesis be high priority.
3. Summary of reasons for proposal: FDA proposes that the mandibular condyle prosthesis be classified into class III.
The act requires the agency to classify into class III a device that presents a po-tential unreasonable risk of illness or injury unless it determines that premarket approval is not necessary to provide reasonable assurance of the safety and effectiveness of the device. In this case, the agency has determined that premarket approval is necessary for this device. FDA believes that the device presents a potential unreasonable risk of illness or injury to the patient if there are not adequate data to ensure the safe and effective use of the device. The agency believes that general controls, either alone or in combination with the special controls applicable to class II devices, are insufficient to provide reasonable assurance of the safety and effectiveness of the device. Therefore, the device should be subject to premarket approval to ensure that each manufacturer of this device develops sufficient information to provide reasonable assurance that it is safe and effective.
4. Summary of data on which the proposal is based. FDA is basing its proposal on the Dental Products Panel members' personal knowledge of, each clinical experience which the device and presentations by Panel members and interested parties (Ref. 1).
5. Risks to health. The following risks are associated with the mandibular condyle prosthetic (a) Implant loosening or displacement. The screws used to anchor the implant may loosen, resulting in implant loosening or displacement causing changes in bite, difficulty in chewing, limited joint function and unpredictable wear on implant.components; (b) Degenerative changes in the natural articulating surfaces. Implant breakdown may result in erosion or resorption of the glenoid fossa. The erosion or resorption may result in intense pain, changes in bite, difficulty in chewing and limited joint function; (c) Foreign body reaction. Implant deterioration and migration may result in a foreign body reaction characterized by multinucleated giant cells; (d) Infection. If the implant cannot be properly sterilized, infection may result; (e) Loss of implant integrity. If the implant materials are unable to withstand mechanical loading the implant can be torn, worn, perforated, delaminated, fragmented, fractured, or fatigued, resulting in failure of the device to function properly; (f) Corrosion. If the implant materials are subject to corrosion, toxic elements may migrate to various parts of the body; (g) Chronic pain. Degenerative changes within the articular surfaces and components of the temporomandibular joint due to implant breakdown may result in chronic pain; (h) Changes to the contralateral joint. Unilateral placement of the implant may result in deterious effects to the contralateral joint; and (i) Malocclusion. Placement of this device may produce an improper occlusal relationship.
D. Interarticular Disc Prosthesis (Interpositional Implant)
The Dental Products Panel make the following recommendations regarding the classification of the interarticular disc prosthesis (interpositional implant).
1. Identification. An interarticular disc prosthesis (interpositional implant) is a device that is intended to be implanted in the human jaw to replace the natural disc and act as an interface between the natural articulating surface of the mandibular fossa.
2. Recommended classification: Class III (premarket approval). The Panel recommends that premarket approval of
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the interarticular disc prosthesis. (interpositional implant) be high priority.
3. Summary of reasons for recommendations: The Dental Products Panel recommends that the interarticular disc prosthesis be classified into class III because the Panel believes that premarket approval is necessary to provide reasonable assurance of the safety and effectiveness of the device. The Dental Products Panel also believes that the device presents a potential unreasonable risk to health and that insufficient information exists to determine that general controls would provide reasonable assurance of the safety and effectiveness of the device. The Dental Products Panel believes that a performance standard would not provide reasonable assurance of the safety and effectiveness of the device and that there is not sufficient and that there is not sufficient information to establish such a standard. Therefore, the device should be subject to premarket approval to ensure that each manufacturer of this device develops sufficient information to provide reasonable assurance that it is safe and effective.
4. Summary of data on which the recommendation is based: The Dental Products Panel based its recommendation on the Panel members' personal knowledge of, and clinical experience with, the device and presentations by Panel members and interested parties (Ref. 1).
5. Risks to health: The following risks are associated with the interarticular disk prosthesis (interpositional implant): (a) Loss of implant integrity. If the implant materials are unable to withstand mechanical loading, the implant material can be torn, perforated, delaminated, or fragmented, resulting in failure of the device to function properly (Refs 4, 6 through 10, and 12 through 15); (b) Implant migration. Torn, worn, perforated, delaminated, and fragmented implant materials are capable of migrating to surrounding tissues, including the lymph nodes (refs. 4 and 13); (c) Foreign body reaction. Implant deterioration and migration may result in a foreign body reaction characterized by multinucleated giant cells (Refs. 4 and 6 through 15); (d) Degenerative
changes within the articular surfaces and components of the joint. Implant breakdown may result in severe resorption of the head of the mandibular condyle and glenoid fossa. The degenerative changes may result in joint noise, changes in bite, difficulty in chewing, severely limited joint function, erosion or perforation into the middle cranial fossa, crepitus, avascular necrosis and fibrous ankylosis (Refs. 4 and 6 through 14); (e)
Implant displacement. Displacement of the implant may result in changes in bite, difficulty in chewing and limited joint function; (Refs. 6 through 9, 11, and 12); (f) Infection. If the implant cannot be properly sterilized, infection, may result.
FDA agrees with the Dental Products Panel's recommendations and is proposing that the interarticular disc prosthesis (interpositional implant) be classified into class III (premarket approval).
The act requires the agency to classify into class III a device that presents a potential unreasonable risk of illness or injury unless it determines that premarket approval is not necessary to provide reasonable assurance of the safety and effectiveness of the device. In this case, the agency has determined that premarket approval is necessary for this device. FDA believes that the device presents a potential
unreasonable risk of illness or injury to the patient if there are not adequate data to ensure the safe and effectiveness use of the device. The agency believes that general controls, either alone or in combination with the special controls applicable to class II devices, are insufficient to provide reasonable assurance of the safety and of the device.
The agency notes that, in addition to the risks to health identified by the Dental Products Panel, the following risks to health also are associated with the device; (g) Chronic pain. Degenerative changes within the articular surfaces and components of the joint due to implant breakdown may result in chronic pain (Refs. 6 through 8 and 11); (h) Calcification. Implant breakdown may result in the formation of scar tissue, leading to
calcification (refs. 10 and 15); (i) Granulomatous reaction. Implant particulate may produce a mass of nodule of chronically inflamed tissue with granulation (Refs. 12 through 15); (j) Leaching of elements. Toxic elements may be leached from the implant materials and migrate to various parts of the body.
III. References
The following references have been placed on display in the Dockets Management Branch (address above) and may be seen by interested persons from 9:00 a.m. to 4 p.m., Monday through Friday.
1. Transcripts of the Dental Products Panel meeting, April 21, 1989
2. Fontenot, M. G. and J. N. Kent, "In-vitro and In-Vivo Wear Performance of TMJ Implants," abstract, International Association of Dental Research, 1991.
3. Kent, J. N. and M. S. Block, "Comparison of FEP and UPE Glenoid Fossa Prosthesis," abstract, International Association of Dental Research, 1991.
4. "Clinical information on the Vitek TMJ Interpositional (IPI) Implant and the Vitek-Kent (VK) and Vitek-Kent 1 (VK-1) TMJ Implants; and in "Vitek Patient Notification Program," an FD publication, 1991.
5. Kent, J. N., "VK Partial and Total Joint Reconstruction," Current Concepts of TMJ Total Joint Replacement, University of Medicine and Dentistry of New Jersey. pp. 1-8, March 1992.
6. Primely, D., Jr., "Histological and Radiological Evaluation of the Proplast-Teflon Interpositional Implant in Temporomandibular Joint Construction Following Meniscectomy," thesis. Masters Degree in Oral Maxillofacial Surgery, University of Iowa, May 1987.
7. Westlund, K. J., "An Evaluation Using Computerized Tomography of Clinically Asymptomatic Patients Following Meniscectomy and Temporomandibular Joint Recon-
struction Using the Proplast-Teflon Interpositional Implant," thesis. Masters Degree in Oral and Maxillofacial Surgery, University of Iowa, May 1989.
8. Wagner, J. D. and E. L. Mosby, "Assessment of Proplast-Teflon Disc Replacements" Journal of Oral and Maxillofacial Surgery, 48: 1140-1144, 1990.
9. Florine, B. L., et al. "Tomographic Evaluation of Temporomandibular Joints Following Discoplasty or Placement of Polytetrafluroethylene Implants," Journal of Oral and Maxillofacial Surgery, 48:183-188, 1988.
10. Heffez, L. et al., "CT Evaluation of TMJ Disc Replacement with a Proplast Teflon Laminate, "Journal of Oral and Maxillofacial Surgery, 45: 657-665, 1987.
11. Ryan, D. E., "Alloplastic Implants in the Temporomandibular Joint," Oral and Maxillofacial Surgery Clinics of North America 1:427, 1989
12. Valentine, J. D., "Light and Electron Microscopic Evaluation of Proplast II TMJ Disc Implants," Journal of Oral and Maxillofacial Surgery, 47:689-696, 1989.
13. Logrotteria, L. et al., "Patient with Lymphadenopathy Following Temporo-mandibular Joint Arthroplasty with Proplast," The Hour of Craniomandibular Practice, vol. 4, No. 2:172-178, 1986.
14. Beraduci, J. P. et al., "Perforation into Middle Crania Fossa as a Sequel to Use of a Proplast-Teflon Implant for Temporomandibular Joint Reconstruction," Journal of Oral and Maxillofacial Surgery, 46:496-498, 1990.
15. Berman, D. N. and S.L. Bronstein, "Osteo Phytic Reaction to a Polytetrafluoroethylene Temporomandibular Joint Implant," Oral Surgery, Oral Medicine, Oral Pathology, (continues the Oral Surgery Section of the American Journal of Orthodonitcs and Oral Surgery), 69:20-23, 1990.
IV. Environmental Impact
The agency has determined under 21 CFR 25.24(e)(2) that this action is of a type that does not individually or cumulatively have a significant effect on
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the human environment. Therefore, neither an environmental assessment nor an en-
vironmental impact statement is required.
V. Economic Impact
The agency has examined the economic impact of this proposed rule and has determined that it does not require a regulatory impact analysis, as specified in Executive Order 12291, because the proposed rule would not impose any new requirements. Therefore, the agency concludes that the proposed rule is not a major rule as defined in Executive Order 12291. The proposed rule does not impose any paperwork requirements.
List of Subjects in 21 CFR Part 872
Medical Devices
Therefore, under the Federal Food, Drug and Cosmetic Act, and under authority delegated to the Commissioner of Food and Drugs, it is proposed that 21 CFR part 872 be amended as follows:
PART 872-DENTAL DEVICES
1. The authority citation for 21 CFR Part 872 continues to read as follows:
Authority: Secs. 501, 510, 513, 515, 520, 701, of the Federal Food, Drug, and Cos-metic Act (21 U.S.C. 351, 360, 360c, 360e, 360j, 371).
2. New 872.3940, 872.3950, 872.3960 and 872.3970 are added to subpart D to read as follows:
872.3940 Total Temporomandibular joint prosthesis.
(a) Identification. A total temporomandibular joint prosthesis is a device that is intended to be implanted in the human jaw to replace the mandibular condyle and augment the glenoid fossa to functionally reconstruct the temporomandibular joint.
(b) Classification. Class III
(c) Date PMA or notice of completion of a PDP is required (Insert date 90 days after the publication of the final rule in the Federal Register.)
872.3950 Glenoid fossa prosthesis
(a) Identification. A glenoid fossa prosthesis is a device that is intended to be implanted in the temporomandibular joint to augment a glenoid fossa and to provide an articulation surface for the head of a naturally occurring mandibular condyle.
(b) Classification Class III
(c) Date PMA or notice of completion of a PDP is required. The effective date of the requirement for premarket approval has not been established. See 872.3
872.3960
(a) Identification. A mandibular condyle prosthesis is a device that is intended to be implanted in the human jaw to replace the mandibular condyle and to articulate within a naturally occurring glenoid fossa.
(b) Classification. Class III
(c) Date PMA or notice of completion o a PDP is required. The effective date of the requirement for premarket approval has not been established. See 872.3
872.3970 Interarticular disc prosthesis (interpositional implant)
(a) Identification. An interarticular disc prosthesis (interpositional implant) is a device that is intended to be implanted in the human jaw to replace the natural disc, and act as an interface between the natural articulating surface of the mandibular condyle and glenoid fossa.
(b) Classification. Class III
(c) Date PMA or notice of completion of a PDP is required. The effective date of the requirement for premarket approval has not been established. See 872.3
Dated; August 9, 1992
Michael R. Taylor
Deputy Commissioner for Policy.
[FR Doc. 92-22621 Filed 9-17-92: 8:45 am]
BILLING CODE 4100-01-M
________________________________________________________________________END-rest of page is Department of Transportation for the Coast Guard which does not apply here, so omitted..
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APPENDIX 7. SUMMARY OF NIH MEETING ON JAW IMPLANTS
OFFICE OF RESEARCH ON WOMEN'S HEALTH
NATIONAL INSTITUTE OF HEALTH
TEMPOROMANDIBULAR DISORDERS AND IMPLANT DEVICES
MEETING SUMMARY

Overview
On July 14, 1992, the Office of Research on Women's Health (ORWH) arranged a meeting with Terrie Cowley and Jennifer Hutchinson of the Temporomandibular Joint Association (TMJA) and representatives of the Food and Drug Administration (FDA) and National Institutes of Health (NIH) to discuss issues related to temporomandibular disorders (TMDs) and implant devices. The goal of the meeting was to identify patient concerns and research opportunities, to review current and future activities related to TMDs, and to obtain recommendations for improving the health status of TMD patients. Issues Discussed
A. Patient Concerns
Officials of TMJA have become increasingly aware of patient concerns related to muscu-loskeletal, immunological, neurological, dermatological, and psychological symptoms. A greater number of patients are reporting constant and severe orofacial pain, fibroid tumors, visual and auditory impairment, dyslexia, rashes, and mental health disorders.
Abnormal bone resorption, a physiological response to a foreign body, such as certain TMJ implant material, may require removal of the implant device. As a result of bone resorption, an open bite can develop which contributes to orofacial pain of varying degrees.
Fear that future implant device availability may be severely limited or restricted results in patient anxiety, frustration, and anger. Insufficient follow of TMD implant patients occurs which contributes to inaccurate assumptions regarding post-implant status. According to TMJA officials, greater attention is being given to the high incidence of "iatro-epidemic" diseases.
B. Current and Future Activities Related to TMDs
Major NIH and FDA activities include:
-Ongoing basic and clinical research on orofacial pain and TMDs
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-Development of TMD research diagnostic criteria (to be published in the December issue of the Journal of Craniomandibular Disorders, Facial, and Oral Pain)
-NIDR Meta-analysis study
The National Institute of Dental Research (NIDR) is conducting a comprehensive review of current literature on TMD treatment in peer-reviewed journals. By using criteria and statistical procedures that permit pooling of data, new treatment protocols and modalities can be identified.
The results of the meta-analysis study will serve as a tool in planning a 1993 World Workshop on Chronic Orofacial Pain and TMDs sponsored by the National Institute of Dental Research.
-Sponsorship of TMD international conference
The World Workshop will review the state of science in the area of chronic orofacial pain and TMDs. Basic research joint and muscular pain, diagnostics, and treatment modalities will be highlighted. Studies involving biomaterials utilized in implants and load-bearing joints will be reviewed. The conference will serve as catalyst for the development of education and resource materials for patients and practitioners.
-Inter-agency and Intra-agency collaboration
The National Institute of Dental Research, the National Institute on Arthritis and Musculoskeletal and Skin Diseases (NIAMS), the National Institute of Allergy and Infec-tious Diseases (NIAID), and the Food and Drug Administration are collaborating in TMD activities.
C. Research Opportunities
-Biomaterials and immunological responses
Greater research on biomaterials used in implant devices, including silicone, is needed to ascertain the risks and benefits to implant recipients and to develop new devices. The
NIAID has issued a Request for Applications for research to study the effects of silicone, a common product used in the manufacture of various types of implant devices, on the immune system.
-Data collection
There is a need for accurate determination of the incidence and prevalence of TMDs. Partnerships with patients, clinicians, researchers, and academicians are viable
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mechanisms for obtaining better epidemiological data and increasing the scientific knowledge base.
Recommendations
-Data Collection Tools: Registries and Surveys
Develop patient registries that enhance data collection efforts and facilitate documentation and research on disease onset, intervention, treatment, and prevention.
Create and implement questionnaires, such as the recent NCHS National Health Inter-view Survey on chronic pain, or other surveys of the National Center for Health Statistics, as mechanisms for increasing the amount and depth of scientific knowledge.
-Collaboration
Continue joint dialogue with multidisciplinary experts, intra-agency and inter-agency re-
presentatives, clinicians, academicians, patients, and public advocates.
Meeting Attendees
Vivian W. Pinn, M.D. ORWH
Judith H. LaRosa, Ph.D. ORWH
Patricia Bryant, Ph.D. NIDR
Terrie Cowley, President TMJ Association
Stephen L. Gordon, Ph.D. NIAMS
Jennifer Hutchinson, Vice-President TMJ Association
Elizabeth D. Jacobson, Ph.D. FDA/CDRH
Lireka P. Joseph, Dr.P.H. FDA/DCRH
Dushanka V. Kleinman, D.D.S., M.Sc.D. NIDR
Ruth Merkatz, Ph.D. OD/FDA
Chuck Sabatos OD/DLA
Barry E. Sands FDA/CDRH
Tracy Summers FDA/CDRH
Susan A. Sztein, M.D. NIAID
Joan Wilentz NIDR
Susan Wise NIDR
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Appendix 8.--Followup Memorandum on the June 4, 1992,
Subcommittee Hearing on Jaw Implants
December 23, 1992

TO: Donald M. Payne
FROM: Diana M. Zuckerman (initialed DMZ)
RE: Followup Memorandum on the June 4, 1992 Subcommittee Hearing on Jaw Implants
The subcommittee on Human Resources and Intergovernmental Relations held a hearing on research and regulations regarding temporomandibular (jaw) implants on June 4, 1992
The hearing focused on the pain and problems associated with various types of TMJ implants, and with the failure of the FDA and NIH to ensure that research was conducted on their safety and effectiveness.
This memorandum summarizes the issues raised at the hearing and new developments that have occurred since then.

BACKGROUND

Temporomandibular disorder (TMD) is a common but vaguely defined disorder involving pain and other symptoms in the area near the temporomandibular joints (TMJ) that attach the jaw to the skull. (You can feel the joints by putting your fingers in front of your ears, while opening and shutting your mouth.) Between 500,000 and 1 million new patients seek treatment each year. These patients suffer from facial pain, limited range of motion in terms of opening the mouth, and other problems. Most are treated with physical therapy, drugs, or splints rather than surgery; however,

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there are approximately 750,000 patients in the United States who have had at least one TMJ surgery.
TMD is the more current term, but essentially means the same thing as TMJ. The main parts of the joint are the condyle, the fossa, and the disc.
Between 80-90 percent of TMJ patients are women, and most are 20-40 years old. Women are apparently more likely to develop TMJ problems naturally; men tend to develop them after an accident. The most famous TMJ patient is Burt Reynolds, who was bedridden and unable to work for 2 years. He had severe pain and vertigo but did not get implants. As is frequently the case, his pain was treated with painkillers, halcion, and other drugs; according to articles about Reynolds, the drugs may have caused at least as many problems as the disorder itself.
In the most severe cases, implants are used to replace one or all of the parts that make up the TMJ. Experts estimate that 75,000 to 100,000 patients have received arti-ficial implants. Three or four times as many have had autogenous bone grafts from their own ribs or other bones, or implants made of cadaver bone or tissue. However, bone grafts and implants usually last only a few years and will usually be replaced with synthetic implants.
The American Association of Oral and Maxillofacial Surgeons has 6,000 members; approximately 70 percent perform TMJ surgery. There is considerable concern within the profession that TMJ problems are difficult to treat and have been overtreated in the past. The American Dental Association states that 80 percent of

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TMD patients get better with or without treatment. However, the pain of TMD can be de-bilitating, and patients do not always want to wait to see if they will get better without surgery.
There are several types of jaw implants, replacing different parts of the jaw, made of different substances, by different manufacturers.
Bone and Other "Natural" Implants
The most commonly used implants have been made of bones, cartilage, muscle flaps, dermis (the layer of skin just below the outside skin layer), or dura (a membrane covering the brain and spinal cord), usually from the patient (such as piece of rib) or from a cadaver. The experts acknowledge that these implants will dissolve after a few years, and cause foreign body giant cells to secrete enzymes, which can cause tissue destruction and other problems. If they are replaced with another bone graft or implant, subsequent replacements tend to last an even shorter time than the first. For that reason, bone grafts and implants tend to be replaced with synthetic implants. Cadaver implants are more likely to be rejected by the "host" but autogenous bone grafts have the disadvantage of requiring two surgeries: One to remove the bone from the rib or wherever, and the second to implant it in the jaw.
Grafts made from bone, cartilage, and other tissue are not regulated by the FDA. However, implants made from cadaver bones or tissues are supposed to be regulated by the FDA; but they rarely are.

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ARE FDA AND NIH IGNORING THE DANGERS OF TMJ (JAW) IMPLANTS

HEARING
BEFORE THE
HUMAN RESOURCES AND INTERGOVERNMENTAL RELATIONS SUBCOMMITTEE OF THE COMMITTEE ON GOVERNMENT OPERATIONS HOUSE OF REPRESENTATIVES

ONE HUNDRED SECOND CONGRESS
SECOND SESSION

JUNE 4, 1992

PRINTED FOR THE USE OF THE COMMITTEE ON GOVERNMENT OPERATIONS

US GOVERNMENT PRINTING OFFICE
68-249 CC WASHINGTON : 1993

FOR SALE BY THE U. S. GOVERNMENT PRINTING OFFICE
SUPERINTENDENT OF DOCUMENTS, CONGRESSIONAL SALES OFFICE, WASHINGTON, DC 20402
ISBN 0-16-041398-2


COMMITTEE OF GOVERNMENT OPERATIONS
JOHN CONYERS, JR. MICHIGAN, CHAIRMAN

CARDISS COLLINS, Illinois FRANK HORTON, New York
GLENN ENGLISH, Oklahoma WILLIAM F. CLINGER, Jr.,, Pennsylvania
HENRY A. WAXMAN, California AL MCCANDLESS, California
TED WEISS, New York J. DENNIS HASTERT, Illinois
MIKE SYNAR, Oklahoma JON L. KYL, Arizona
STEPHEN L. NEAL, North Carolina CHRISTOPHER SHAYS, Connecticut
DOUG BARNARD, Jr.,, Georgia STEVEN SCHIFF, New Mexico
TOM LANTOS, California C. CHRISTOPHER COX, California
ROBERT E. WISE, Jr.,, West Virginia CRAIG THOMAS, Wyoming
BARBARA BOXER, California ILEANA ROS-LEHTINEN, Florida
MAJOR R. OWENS, New York RONALD K. MACHTLEY, Rhode Island
EDOLPHUS TOWNS, New York DICK ZIMMER, New Jersey
BEN ERDREICH, Alabama WILLIAM H. ZELIFF, Jr.,,, New Hampshire
GERALD D. KLECZKA, Wisconsin DAVID L. HOBSON, Ohio
ALBERT G. BUSTAMANTE,Texas SCOTT L. KLUG, Wisconsin
MATTHEW G. MARTINEZ, California
DONALD M. PAYNE, New Jersey BERNARD SANDERS, Vermont
GARY A. CONDIT, California (Independent)
PATSY T. MINK, Hawaii
RAY THORNTON, Arkansas
COLLIN C. PETERSON, Minnesota
ROSA L. DELAURO, Connecticut
CHARLES J. LUKEN, Ohio
JOHN W. COX, Jr.,, Illinois

Julian Epstein, Staff Director
Donald W. Upson, Minority Staff Director

Human Resources and Intergovernmental Relations Subcommittee

Ted Weiss, New York Chairman

HENRY A. WAXMAN, California CRAIG THOMAS, WYOMING
DONALD M. PAYNE, New Jersey WILLIAM H. ZELIFF, Jr., New Hampshire
PATSY T. MINK, Hawaii DAVID L. HOBSON, Ohio
ROSA L. DELAURO, Connecticut
BERNARD SANDERS, Vermont (Ind.)

Ex OFFICIO

JOHN CONYERS, Jr.,, Michigan FRANK HORTON, New York
JAMES R. GOTTLIEB, Staff Director
DIANA M. ZUCKERMAN, Professional Staff Member
ELINOR P. TUCKER, Clerk
STEPHEN D. MCMILLAN, Minority Professional Staff

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CONTENTS
page
Hearing held on June 4, 1992..............................................................................1
Statement of:
Beaulieu, Paula, Tualatin, OR............................................................................17
Benson, James S., Director, Center for Devices and Radiological Health, Food
and Drug Administration....................................................................................77
Cowley, Terrie, cofounder TMJ Association, Ltd., a support and advocacy
organization, Milwaukee, WI...............................................................................6
Fontenot, Mark G., D.D.S., M. Eng., Louisiana State University School
of Dentistry, New Orleans, LA, and the department of mechanical
engineering, University of Southwestern Louisiana, Lafayette, LA..........................25
Lappe', Marc, Ph.D., professor, health policy and ethics, University of
Illinois College of Medicine, Chicago, IL..............................................................52
Laskin, Daniel, D.D.S., professor, Medical College of Virginia; editor,
Journal of Oral and Maxillofacial Surgery.............................................................46
Loe, Harald, M.D., Director, National Institute of Dental Research, accompanied
by Vivian Pinn, M.D., Director, NIH Office of Research on Women's Health;
Dushanka Kleinman, Deputy Director, National Institute of Dental Research,
Joseph Levitt, Director, Center for Devices and Radiological Health, FDA; Steve
Niedelman, Deputy Director, division of compliance operations, Office of Compliance and Surveillance; and Barry Sands, biomedical engineer, Office of Device
Evaluation........................................................................................................98
Marbach, Joseph, D.D.S., Columbia University School of Public Health New
York, NY.........................................................................................................65
Marks, Amy, New Orleans, LA..........................................................................11
Weiss, Hon. Ted, a Representative in Congress from the State of New York and
chairman, Human Resources and Intergovernmental Relations Subcommittee;
Opening statement............................................................................................1
Wolford, Larry M., D.D.S., Baylor University Medical Center, Dallas, TX................37
Letters, statements, etc., submitted for the record by:
Beaulieu, Paula, Tualatin, OR: Prepared Statement.............................................19
Benson, James S., Director, Center for Devices and Radiological Health, Food
and Drug Administration: Prepared statement.....................................................80
Cowley, Terrie, cofounder, TMJ Association, Ltd., a support and advocacy
organization, Milwaukee, WI: Prepared statement.................................................8
Fontenot, Mark G., D.D.S., M. Eng., Louisiana State University School of
Dentistry, New Orleans, LA and the department of mechanical engineering, University
of Southwestern Louisiana, Lafayette, LA: Prepared statement.............................28
Lappe', Marc, Ph.D., professor, health policy and ethics, University of Illinois
College of Medicine, Chicago, IL: Prepared statement..........................................55
Laskin, Daniel, D.D.S., professor, Medical College of Virginia; editor, Journal of
Oral and Maxillofacial Surgery: Prepared statement.............................................48
Loe, Harald, M.D., Director, National Institute of Dental Research: Chronology of
NIDR Temporomandibular Disorders-Related Initiatives.......................................100
Prepared statement........................................................................................106
Marbach, Joseph, D.D.S., Columbia University School of Public Health New
York, NY: Prepared statement...........................................................................66
Marks, Amy, New Orleans, LA: Prepared statement............................................13
Sanders, Hon. Bernard, a Representative in Congress from the State of
Vermont:
FDA documents describing TMJ Implants and registry.......................................134
Instructions for Wilkes TMJ implant and silicone sheeting..................................140

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Letters, statements, etc., submitted for the record by Continued
Sanders Hon. Bernard, a Representative in Congress from the State of
Vermont-Continued
Memo dated December 13, 1988, describing MDR's..........................................130 Memo dated February 1, 1990, concerning decisions by FDA that two
different products were substantially equivalent..................................................121
Summary of article concerning in vivo characterization of the inflammatory
properties of poly(tetrafluoroethylene) particulates..............................................125
Undated draft memo regarding changes to TMJ interpositional implant
manufactured by Dow Corning..........................................................................147
Thomas, Hon. Craig, a Representative in Congress from the State of Wyoming:
Prepared statement............................................................................................3
Weiss, Hon. Ted, a Representative in Congress from the State of New York, and
chairman, Human Resources and Intergovernmental Relations Subcommittee:
Documents regarding Dr. Kent...........................................................................71
Information concerning original surgeon fees.......................................................21
Wolford, Larry M., D.D.S., Baylor University Medical Center, Dallas, TX:
Prepared statement..........................................................................................40

APPENDIXES

Appendix 1.-Letters from TMJ patients and related information............................159
Appendix 2.-Review articles on alloplastic implants...... .....................................197
Appendix 3.-FDA warning letters to manufacturers of jaw implants and FDA
safety alert to dentists.....................................................................................224
Appendix 4.-Documents provided by manufacturers about safety of their jaw
implants.........................................................................................................243
Appendix 5.-Summary of meta-analysis and NIDR requests for proposals for
studies of jaw implants....................................................................................334
Appendix 6.-Federal Register announcement for TMJ implants............................346
Appendix 7.-Summary of NIH meeting on jaw implants.......................................351
Appendix 8.-Followup memorandum on the June 4, 1992, subcommittee hearing
on jaw implants..............................................................................................354

Dow Corning's Silastic TMJ Implant
The FDA's authority to regulate jaw implants is based on the 1976 Medical Devices Amendments to the Food, Drug, and Cosmetic Act. Prior to 1976, device manufacturers were not required to prove that their products were safe or effective. After 1976, silicone sheeting implants intended for the face and jaw made by Dow Corning were "grandfathered" onto the market because they had been sold before the law passed. This sheeting (sold in pieces 6 x 8 inches in size) could be cut into pieces that were used by surgeons to reconstruct the face, to protect nerves in the face, or to create a space to help damaged TMJ joints. The sheeting does not replace the joint itself.
In 1983, Dow Corning submitted a premarket notification [510(k)] to FDA regarding a modification of their implant from permanent sheeting to a temporary TMJ implant (called the Wilkes implant) pre-cut from sheeting; this was cleared by the FDA in 1984. The company told the FDA that the TMJ implant was "substantially equivalent" to the sheeting that was already on the market, since it was just a pre-cut version of the same material. Although the sheeting had been used for TMJ surgery, it had been cleared for marketing for other uses that did not involve as much friction. The FDA apparently ignored the fact that the friction and stress on a TMJ implant would be much greater than for other uses of sheeting, making the implant much more likely to fragment.
The company implicitly admitted the problems that patients were having with their
TMJ sheeting implants by recommending that the pre-cut Wilkes implant be used only for temporary use. Some

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surgeons believe that they can be used to create a space near a missing TMJ disc, since the implants are not safe for long-term implantation. The hope is that, when implanted for only 1-2 months, the body will form scar tissue around the implant (as it does with breast implants and most other implants), and that the implant can be carefully removed, leaving the scar tissue capsule to take the place of the missing pieces of the jaw. However, there are apparently no long-term studies to determine the safety or effectiveness of this technique. Moreover, both the sheeting and the Wilkes implant have sometimes been used as a permanent implant.
Meanwhile, the company continued to change the type of silicone used, as they had with breast implants, without filing an additional 510(k) with the FDA. Most notably, they added barium sulfate so that the implant would show up on x-rays, without ever filing a 510(k). That implant is called the Wilkes Silastic HP. According to FDA documents, there is now a general recognition within the FDA that a 510(k) should have been filed for that for that change. In fact, FDA might have rejected the 510(k) if it had been submitted, because the company could provide no evidence that the implants would function similarly.
Dow Corning did not conduct animal studies or clinical studies to test silicone's safety or effectiveness for the TMJ, according to company documents. Data published in dental journals in the 1980's indicated that TMJ implants made from silicone were de-teriorating, breaking, and cracking, with fragments of the silicone causing foreign body giant cell reactions. There was clear microscopic evidence of foreign body reactions to the silicone in the TMJ implants. This fragmentation has been found to

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cause destructive lesions, bone degeneration, and other serious problems
Dow Corning provides package inserts for the surgeons regarding the risks and benefits of their Wilkes implants, but does not provide a package insert for the surgeons regarding the risks and benefits of their Wilkes implants, but does not provide a package insert for the sheeting. Instead, upon request, they will provide what they call "data sheets." No written information about risks and benefits is made available to the patients, since the surgeon is the user of the product (as was the case with breast implants, until the FDA required information for consumers in September 1991).
VITEK IMPLANTS
The synthetic TMJ implants with the most obvious problems were made by Vitek and later by Oral Surgery Marketing, Inc. (OSMI), a successor corporation of Vitek. Vitek implants were made from teflon and Proplast (a teflon composite product).
After the 1976 FDA device law, some types of Vitek TMJ implants were "grand-fathered," based on "substantial equivalence" to the silicone sheeting material described previously in this memorandum. In other words, the FDA agreed with the company that implants used to replace or reconstruct a jaw joint were essentially the same as an implant that replaces a broken cheekbone (which is subject to much less friction and pressure), even one made of a completely different material. The company did not even
file a 510(k) for each type of jaw implant that they were selling.

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During the 1980's Vitek implants became more popular than the previously used silicone TMJ implants, because dental journal articles indicated that the Vitek implants were safer and more effective during the first two years after surgery. In addition, Vitek made a TMJ implant that could replace the joint, whereas the silicone implants could only be used to cushion the joint.
Dr. John Kent, an oral surgeon and well-respected TMJ researcher at Louisiana State University Medical Center, published studies in the 1980's indicating the safety of Vitek implants. However, a February 14, 1984, letter from Dr. Kent to the president of Vitek, Dr. Charles Homsy, shows that Dr. Kent was concerned about the safety of Vitek implants at the same time he was praising the products in articles in oral surgery journals. The letter indicated that one of his patients had to have the implant removed after a year and a half because of pain and swelling. When he performed surgery on the patient, Dr. Kent found that the implant was badly torn and the capsule was covered in a "heavy black pigment." Based on that experience, Dr. Kent expressed his concern that Vitek might have a "calamity of unbelievable proportions on our hands."
Dr. Kent's concern about such a calamity was apparently at least partly financial; according to legal documents, Dr. Kent had 21,000 shares of Vitek stock at the same time he was publishing articles praising Vitek TMJ implants.
According to a 1988 FDA memorandum, serious safety problems regarding Vitek implants first came to the FDA's attention in an Medical Device Report (MDR) in April 1986, but "the report

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contained no details and was dismissed." The problems caused by Vitek implants were not a secret; at the 1986 annual meeting of the American Association of Oral and Max-illofacial Surgeons, several clinicians reported that fragments of proplast were breaking off the implants, causing giant cell reactions, pain, and bone loss. In 1988, there were published reports from previously enthusiastic surgeons that 21-35 percent of the proplast implants were failing over a 5-year period.
Subsequent reports to FDA's MDR system provided evidence of serious problems, and by late 1988, the FDA had received information from experts that the Vitek were failing and needed to be explanted, and that patients with explanted devices were worse off than they had been before treatment. Problems included excruciating pain and the degeneration of parts of the skull. An oral surgeon notified the FDA that he had been reporting problems to Vitek for the last 3 years, and that FDA determined that Vitek had not reported those problems to the FDA. In November 1988, the FDA sent a "Notice of Adverse Findings" to Vitek, complaining about their MDR procedures.
In April 1989, an FDA panel voted unanimously to classify all TMJ implants as Class III, requiring proof of safety and efficacy. The panel rejected Vitek's claim that clinical experience was sufficient to prove the implants were safe and should therefore be classified as Class II. (These claims were similar to those made by other companies for breast implants in the 1980's.) However, at the time of our June 1992, the FDA had not yet announced the classification of TMJ implants in the Federal Register, and safety data had never been required.

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IPI'S. At the FDA's insistence, Vitek issued a letter dated March 23, 1990, advising doctors that Vitek's interpositional implants (IPI's) could fragment, delaminate, or otherwise be damaged while in normal size. In the summer of 1990, the FDA determined that Vitek's devices were misbranded and adulterated based on "new clinical data that demonstrate new adverse effects." The information was based on two masters theses conducted at the Department of Oral Surgery at the University of Iowa.
Graduate students conducted a retrospective study of 51 patients who received the Vitek TMJ IPI between 1983-86, and found that 73 percent of the implants had been removed due to fragmentation, perforation, or foreign body reaction that resulted in pro-gressive bone degeneration. When the implants of asymptomatic patients were evaluated, the researchers found that 65 percent had been displaced, 50 percent had been fractured or perforated, and that significant bone degeneration was occurring around all implants.
As a result of this study, the FDA informed Vitek that they needed a minimum of 5-year clinical studies to determine that the TMJ replacement implant was equivalent to pre-amendment devices. In June 1990, the company filed for bankruptcy, and another company, Oral Surgery Marketing, Inc., with the same president and the same address, took over their products. In December 28, 1990, the FDA sent a safety alert to oral and maxillofacial surgeons, telling them not to implant any Vitek IPI's.

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On August 30, 1991, the FDA rescinded Vitek's 510(k) for one of their TMJ implants, the IPI, saying that new evidence of adverse reactions indicated that the device was not substantially equivalent to silicone sheeting. After repeated unsuccessful efforts to force Vitek to notify patients of the risks of their implants, on October 2, 1991, the FDA issued a medical alert that advised patients with Vitek IPI's to obtain immediate MRI exams to determine if their implants were breaking or causing bone deterioration. The FDA also urged patients to enroll in an International Implant Registry. Because the company had filed for bankruptcy in June 1990, patients have to pay to enroll in the Registry; few have done so.
An estimated 26,000 Vitek IPI's were distributed between 1983-86 in the United States. This does not include IPI's implanted in 1987 and 1988.
In a recently conducted study by Dr. Mark Fontenot, a dentist and engineer who testified at our hearing, a mechanical TMJ simulator indicated that Vitek IPI implants could be expected to last only 3 years. Had anyone conducted such studies prior to implanting them in humans, the pain and suffering of tens of thousands of patients could have been avoided.
OTHER VITEK TMJ IMPLANTS. Vitek also sold an implant that totally replaced the joint; one of these modes was called the Vitek-Kent I (VK-I). The Department of Oral Surgery at Louisiana State University conducted a retrospective study of 39 VK-I implants used for partial reconstruction and 85 for total

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reconstruction between 1982-86. They found that approximately 40 percent had failed. These researchers did not look at symptomatic patients.
During the years they were sold, numerous changes were made in the Vitek TMJ implants without FDA approval. The total number of implants used between 1974-1990 is not known, nor is the number of patients who still have such implants. In addition to the IPI, implants include the glenoid fossa implant, the condyle implant, the total joint implant, and the sheeting implant. At the time that the company filed for bankruptcy, there were approximately 426 outstanding lawsuits or claims, most involving the IPI or sheeting. There are now more than 2,000. The president of Vitek and OSMI, Charles Homsy, moved to Switzerland, and still claims the proplast jaw implants are safe. According to FDA officials, the Federal Government has made several unsuccessful efforts to collect money from Homsy or the company. Dr. Homsy claims he has no money, and his lawyer told the FDA that he is working pro bono. These Federal efforts are apparently ongoing.
TMJ IMPLANTS, INC.
A third company is called TMJ Implants, Inc. Their jaw implants are made from cobalt chrome with the condyle section made from an acrylic. They are frequently called the Christensen Implant, after its inventor, Robert Christensen, D.D.S. Dr. Christensen is president of TMJ Implants, Inc.
TMJ Implants, Inc., claims that their devices have been in commercial distribution in their present design since the early

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1960's, and are therefore pre-amendment devices. However, an FDA investigator has determined that there has been a change in design since 1976, and another oral surgeon claims that the acrylic section of the implant was added in 1988.
Regardless of whether the implant design changed substantially since 1976, there is another problem: TMJ Implants, Inc., and the FDA agree that since 1990, the company has been selling a pre-sterilized device rather than their previous device, which needed to be sterilized by the doctors. As a result of this change, the FDA told the company in January 1992 that the devices should not be marketed until a 510(k) is submitted and approved. The company argued that the sterilization did not substantially change the device and should not require a 510(k). This argument would be moot if in fact the design of the devices has been changed substantially since 1976. Meanwhile, the implants remain on the market.
Dr. Christensen published three articles about the short-term safety of his implants in 1963-64. Each article described case studies of between 1-3 patients, followed for 1-2 years. However, when the Subcommittee asked him to submit all studies regarding the safety of the implants, he provided individual testimonials rather than any long-term research. The only study he provided was of 49 patients at one medical practice, who were followed for less than 18 months.

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CUSTOM MADE TMJ IMPLANTS
Several companies have attempted to avoid FDA regulations by making "custom" devices that made to uniquely fit each patient. Techmedica is the major company pro-viding such TMJ implants today. Their implants, made of an alloy similar to the most popular orthopedic devices, sell for approximately $10,000 per joint (there are two joints in the jaw). This business is still small; in June 1992, the company claimed that they had sold only 250 devices in the previous 2 years. One of our hearing witnesses, Dr. Larry Wolford, uses these devices; however, there is no long-term safety information. Doctors who have used them for 1-2 years report few problems. However, that was also true of the Vitek device; the first two years of followup were very positive, and the implants failed quickly after that. In June 1992, a company spokesman said that only six patients had had these implants for 3 years.
Techmedica has not conducted safety studies of their TMJ implants. However, they claim that the implants are safe, based on animal studies conducted by other companies evaluating implants made of identical material for other types of joints.
FDA challenged Techmedica's avoidance of regulation based on their "custom made" status, and notified the company that they must file a 510(k).
THE ROLE OF NIH
NIH has the authority to conduct research on TMD and to provide grants to researchers on this topic. Most of this research

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is supported by the National Institute of Dental Research (NIDR) although researchers include psychologists and medical doctors who specialize in pain and other relevant areas of research.
TMD has not been a high priority for NIH, and little research has been supported. The research that is supported rarely evaluates the safety or effectiveness of various treatments, and never evaluated grafts or implants. In fact, the research base is so poor that neither the causes nor preferred treatments for TMJ problems have been determined. An NIH spokesperson informed me that they intentionally do not fund research on implants, because they do not believe implants are an appropriate type of treatment, except in a few cases of severe trauma.
If NIH believes that implants are unsafe, it would not be ethical to support research that encourages the use of implants. However, NIH could support retrospective studies of patients who already have such implants, in order to determine their safety. Such research is less scientifically sound than double blind clinical studies, which randomly assign different treatments. However, the reality is that tens of thousands of patients are falling through the cracks because FDA has not required the manufacturers to conduct safety studies, and NIH has not funded independent researchers to conduct such studies.
In the week following Chairman Weiss' May 1992 letter asking Dr. Bernadine Healy to testify on this topic, NIDR called at least two researchers to encourage them to submit grant applications immediately.

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GENERAL CONCERNS
Currently, there are no TMJ implants that are proven to be safe for long-term use. The Vitek implants are no longer sold, the Dow Silastic implants are now rarely used for permanent replacement because of their poor track record and there is concern that they could cause problems even when used as a temporary measure, and some surgeons are now experimenting with TMJ Implants, Inc., or custom-made implants by other companies. While the TMJ Implants, Inc., and Techmedica implants apparently have reasonable track records for the last 2 years, Vitek and Silastic implants also were considered for the first 2 years of use. The problem tended to arise after 3-5 years, because the pressure and friction caused fragmentation, followed by giant cell development.
Problems resulting from the development of giant cells around jaw implants are now widely acknowledged by oral and maxillofacial surgeons. Several articles acknowledging these problems were published in their major journals in the late 1980's. For example, one review article, written by Dr. Wei Yung Yih and Dr. Ralph G. Merrill,1 described the "evidence of the destructive potential of these implants" to "cause damage that lasts far beyond the removal of the rejected implants' and can damage subsequent tissue grafts. The article also described "immune reactions" with "lymph node involvement by implant particles" that were very difficult to
________________________________________________________________________1-Yih, W.Y. and Merrill, R.G. (1989). Pathology of alloplastic interpositional implants in the temporomandibular joint. Oral and Maxillofacial Surgery Clinics of North America, vol.1, No. 2, pp. 415-426. Dr. Ralph Merrill is a well respected oral and maxillofacial surgeon in this country.

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remove and contributed to the failure of subsequent bone grafts. The authors concluded that proplast and silicone are "not biologically acceptable implant material" in the TMJ.
In contrast, the similar development of giant cells around breast implants was extremely controversial, with plastic surgeons and the manufacturers company touting the biocompatibility of silicone and refusing to acknowledge evidence to the contrary.
When problems arise, the removal of TMJ implants is extremely expensive, and at this time there are no known safe alternatives. Many experts believe it would be much safer to avoid implants to begin with. Once the bone degenerates, there is no known treatment to reverse that process.
DEVELOPMENTS AFTER THE HEARING
NIDR. Shortly before the hearing, NIDR funded a research to conduct a met-analysis of all the research studies that had been conducted on TMJ treatment. A meta-analysis is a statistical method used to combine information from several well conducted studies, to attempt to provide more conclusive information. At the June 1992 hearing, Rep. Bernard Sanders, who was temporarily serving as Chairman Weiss' request, asked whether such a study was worthwhile, given the lack of well-conducted research in the field. The conclusions of this meta-analysis were consistent with those concerns; the researcher concluded that the studies that had been done were inadequate to enable a meta-analysis to indicate whether or not any surgical treatments are safe.

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FDA. Shortly before the hearing, the FDA sent warning letters to all the manufacturers of TMJ implants except Dow Corning, regarding their need to provide 510(k) applications for their products indicating they are substantially equivalent to pre-amendment devices.
The FDA has determined that the "Christensen device" made by TMJ Implants, Inc., is a pre-amendment device since it was first sold in the 1960's, and that any other TMJ implants that can prove to be substantially equivalent to that device can be sold. However, as previously noted, the most recently sold Christensen device was different from the one that had been sold prior to 1976 in at least one respect, because the pre-1976 implant was not pre-sterilized. Therefore, TMJ Implants, Inc., has been told they cannot sell their pre-sterilized device until they have a 510(k) approval by FDA.
On September 18, 1992, 3 months after the Subcommittee hearing, the FDA published the final rule in the Federal Register categorizing TMJ implants as Class III devices. The announcement notified manufactures that safety data would be required in 30 months, the minimum time by law.
Meantime, the FDA is willing to consider whether any currently sold TMJ implants are substantially equivalent to the Christensen device, even though the other jaw implants are made of different materials. At a December 16, 1992, briefing from Joe Levitt, Deputy Director of FDA's Center for Devices and Radiological Health, and other FDA staff, I was told that the fact that the other TMJ implants are made of completely different materials than the Christensen device may not be an impediment to approving a

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510(k). However, FDA officials told me that they would expect some clinical research to back up claims of substantial equivalence.
Despite the clear evidence that Dow Corning's silastic sheeting and Wilkes temporary TMJ implant are substantially different from pre-amendment devices, because of changes labeling and changes in material, the FDA has not yet sent even a warning letter to require a 510(k) from Dow Corning. It is this kind of omission that causes critics to say it is still "business as usual" at the Center for Devices and Radiological Health at the FDA. At my December 1992 briefing, the FDA officials had no explanation as to why they had done nothing about the Dow Corning devices except to question whether Dow Corning would continue to sell those devices, I read them a recent article indicating that although Dow Corning would stop selling several silicone products, they were continuing their marketing of silastic sheeting and the Wilkes TMJ implant.
At the December 1992 briefing, the FDA staff expressed concern that the currently sold TMJ implants should remain on the market for the foreseeable future, because there are no alternatives. This might seem to be a reasonable approach for the placement of failed implants, but seems to me impossible to justify for patients who have not yet had any jaw implants.

RECOMMENDATIONS

1. The FDA should require all manufacturers to prove that their TMJ implants are safe and effective for at least 5 years. These

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data should be due 30 months from the final rule that was published on September 18, 1992. Prospective studies, comparing patients who receive implants or nonsurgical treatments should be conducted for at least 2 years, and retrospective studies should provide data for at least 5 years.
2. The FDA should immediately require 510(k) applications from all manufacturers of the TMJ implants, including Dow Corning.
3. The FDA's process for approving 510
510(k) applications needs to be more stringent. The criteria for "substantial equivalence" has been so loose, that more than 90 percent of those are submitted are approved. As long as this continues, companies have no incentive to provide safety data to the FDA.
4. Postmarket surveillance should be required to determine the longer term safety of TMJ implants after any PMA's are approved.
5. NIH should determine whether NIDR is the most appropriate institute for research on TMD and jaw implants. NIH should ensure that NIDR or another institute immediately fund research comparing the safety and effectiveness of various treatments, including implants, grafts, and nonsurgical treatments.
6. The FDA should work more closely with oral and maxillofacial surgeons to inform them of the adverse reactions associated with jaw implants, and to ensure that they notify Vitek patients of the dangers of their implants. Previous FDA efforts have obviously not been successful. At this point, it seems necessary for the FDA to conduct a more effective public information campaign, since working

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with the surgeons directly has not reached a sufficient number of patients.

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WE ARE ANGELS UNITED ON TMJ!! TMJD_SAFE_HAVEN_4_LIFE_ISSUES · TMJ SUPPORT GROUP This TMJD Support Group is intended to be a Safe Haven and provide a place where people with TMJ pain can come and offer and receive support from people who know what they are going through. This is not a medical group and we do not have medical degrees or medical backgrounds. However, with the variety of members in here, there is bound to be someone who has been there and done that and can answer your questions. This group is in memory of Debbie Ward whom suffered from TMJD & died of unknown causes. There are many types of members with TMJD. Some have been treated medically, some treated with various splint therapies and physical therapies as well as some with surgical treatments ranging from Arthroscopy to full jaw joint replacements. Everyone with any degree of TMJD or has a family member that deals with it is welcome to join and offer and receive support that we all so badly need to get through each day with the pain we have to live with. It is YOUR place to cry, scream or vent on the pain you are dealing with and how it is affecting your life and the lives of your loved ones. The group is MODERATED to avoid the unsolicited advertisements and spam. We are all in pain and do not need to have to deal with that too. TMJ SURGERY FAMILY!. A Great Place to Share Information! This site is for sharing and is not a substitute for the advise of your physician/oral surgeon. Please consult with your health care professional.

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