Orthopedic Devices: Classification and 
Reclassification of Pedicle Screw Spinal 
Systems 
[Federal Register: July 27, 1998 (Volume 63, 
Number 143)] 
[Rules and Regulations]      
         [Page 40025-40041] 

From the Federal Register Online via GPO 
Access [wais.access.gpo.gov] 
[DOCID:fr27jy98-7] 
---------------------------------------------
--------------- 
DEPARTMENT OF HEALTH AND HUMAN SERVICES 
Food and Drug Administration 
21 CFR Part 888 
[Docket No. 95N-0176] 
RIN 0910-ZA12 

 
Orthopedic Devices: Classification and 
Reclassification of 
Pedicle Screw Spinal Systems 

Agency: Food and Drug Administration, 
HHS. 

Action: Final rule. 
---------------------------------------------
--------------- 
SUMMARY: The Food and Drug Administration 
(FDA) is classifying certain previously 
unclassified preamendments pedicle screw 
spinal systems into class II (special 
controls) and reclassifying certain 
postamendments pedicle screw spinal systems 
from class III (premarket approval) to class 
II. FDA is taking this action because it 
believes that special controls would provide 
reasonable assurance of safety and 
effectiveness. This action is being taken 
under the Federal Food, Drug, and Cosmetic 
Act (the act), as amended by the Medical 
Device Amendments of 1976 (the 1976 
amendments), the Safe Medical Devices Act of 
1990 (the SMDA), and the Food and Drug 
Administration Modernization Act of 1997 
(FDAMA). 
EFFECTIVE DATE: August 26, 1998. 
FOR FURTHER INFORMATION CONTACT: Aric D. 
Kaiser, Center for Devices and Radiological 
Health (HFZ-410), Food and Drug 
Administration, 9200 Corporate Blvd., 
Rockville, MD 20850, 301-594-2036. 
SUPPLEMENTARY INFORMATION: 
Table of Contents 
I. Background 
II. Regulatory History of the Device 
III. Summary of the Final Rule 
IV. Proposed Rule Clarifications 
V. Analysis of Comments and FDA's Response 
    A. Issues Relating to the Recommendations 
of the Panel, FDA's Tentative Findings, and 
Summary of the Data Upon Which FDA's Findings 
Were Based 
    B. Issues Relating to Information 
Published in the 1994 
Supplementary Issue of the Journal Spine 
(vol. 20S, 1994) 
  C. Issues Relating to the January 1995, 
510(k) Substantial 
Equivalence Determination for a Pedicle Screw 
Spinal System Intended for Severe 
Spondylolisthesis 
    D. Issues Relating to Misstatements or 
False Statements 
Appearing in the Proposed Rule 
    E. Issues Relating to the FDA's Issuance 
of Regulations 
    F. Responses to Comments Which Contained 
Clinical Data 
  G. Requests for Additional Pedicle Screw 
Clinical Trials and Data Analyses 
    H. Issues Relating to Indications for Use 
    I. Issues Relating to Special Controls 
    J. Other Issues 
    K. Labeling of Bone Screws 
    L. Review of New Pedicle Screw Spinal 
System 510(k)'s 
  M. Review of New Information Published and 
Submitted After 
Publication of the Proposed Rule: Pedicle 
Screw and Related 
Literature and MedWatch and MDR System 
Reports 
VI. References 
VII. Environmental Impact 
VIII. Analysis of Impacts 
I. Background 
    The act (21 U.S.C. 331 et seq.), as 
amended by the 1976 amendments (Pub. L. 
94-295), the SMDA (Pub. L. 101-629), and 
FDAMA (Pub. L. 105- 
115), established a comprehensive system for 
the regulation of medical devices intended 
for human use. Section 513 of the act (21 
U.S.C. 360c) established three categories 
(classes) of devices, depending on the 
regulatory controls needed to provide 
reasonable assurance of their safety and 
effectiveness. The three categories of 
devices are: Class I (general controls), 
class II (special controls), and class III 
(premarket approval). 
    Under section 513 of the act, devices 
that were in commercial distribution before 
May 28, 1976 (the date of enactment of the 
1976 amendments), generally referred to as 
preamendments devices, are classified after 
FDA has: (1) Received a recommendation from a 
device classification panel (an FDA advisory 
committee); (2) published the panel's 
recommendation for comment, along with a 
proposed regulation classifying the device; 
and (3) published a final regulation 
classifying the device. FDA has classified 
most preamendments devices under these 
procedures. 
    Devices that were not in commercial 
distribution prior to May 28, 1976, generally 
referred to as postamendments devices, are 
classified automatically by statute (section 
513(f) of the act) into class III without any 
FDA rulemaking process. Those devices remain 
in class III and require premarket approval, 
unless and until: (1) The device is 
reclassified into class I or II; (2) FDA 
issues an order classifying the device into 
class I or II in accordance with new section 
513(f)(2) of the act, as amended by FDAMA; or 
(3) FDA issues an order finding the device to 
be substantially equivalent, in accordance 
with section 513(i) of the act, to a 
predicate device that does not require 
premarket approval. The agency determines 
whether new devices are substantially 
equivalent to previously offered devices by 
means of premarket notification procedures in 
section 510(k) of the act (21 
U.S.C. 360(k)) and part 807 of the 
regulations (21 CFR part 807). A 
preamendments device that has been classified 
into class III may 
be marketed, by means of premarket 
notification procedures, without submission 
of a premarket approval application (PMA) 
until FDA promulgates a final regulation 
under section 515(b) of the act (21 
U.S.C. 360e(b)) requiring premarket approval. 
    Reclassification of classified 
preamendments devices is governed by section 
513(e) of the act. This section provides that 
FDA may, by 
rulemaking, reclassify a device (in a 
proceeding that parallels the initial 
classification proceeding) based upon ``new 
information.创 The reclassification can be 
initiated by FDA or by the petition of an 
interested person. The term ``new 
information,创 as used in section 513(e) of 
the act, includes information developed as a 
result of a reevaluation of the data before 
the agency when the device was originally 
classified, as well as information not 
presented, not available, or not developed at 
that time. (See, e.g., Holland Rantos v. 
United States Department of Health, 
Education, and Welfare, 587 F.2d 1173, 1174 
n.1 (D.C. Cir. 1978); Upjohn v. Finch, 422 
F.2d 944 (6th Cir. 1970); Bell v. Goddard, 
366 F.2d 177 (7th Cir. 1966).) 
  Reevaluation of the data previously before 
the agency is an appropriate basis for 
subsequent regulatory action where the 
reevaluation is made in light of newly 
available regulatory authority (see Bell v. 
Goddard, supra, 366 F.2d at 181; Ethicon, 
Inc. v. FDA, 762 
F. Supp. 382, 389-91 (D.D.C. 1991)), in light 
of changes in ``medical science.'' (See 
Upjohn v. Finch, supra, 422 F.2d at 951.) 
Regardless of whether data before the agency 
are past or new data, the ``new information'' 
on which any reclassification is based is 
required to consist ``valid scientific 
evidence,创 as defined in section 513(a)(3) 
of the act and Sec. 860.7(c)(2) (21 CFR 
860.7(c)(2)). (See, e.g., General Medical Co. 
v. FDA, 770 F.2d 214 (D.C. Cir. 1985); 
Contact Lens Assoc. v. FDA, 766 F.2d 592 
(D.C. Cir.), cert. denied, 474 U.S. 1062 
(1985).) FDA relies upon ``valid scientific 
evidence创 in the classification process to 
determine the level of 
[[Page 40026]] 
regulation for devices. For the purpose of 
reclassification, the valid scientific 
evidence upon which the agency relies must be 
publicly available. Publicly available 
information excludes trade secret and/or 
confidential commercial information, e.g., 
the contents of a pending PMA. (See section 
520(c) of the act (21 U.S.C. 360j(c).) 
II. Regulatory History of the Device 
  Consistent with the act and the regulation, 
FDA referred the proposed classification and 
reclassification of pedicle screw spinal 
systems to the Orthopedic and Rehabilitation 
Devices Panel (the Panel), an FDA advisory 
committee, for its recommendation on the 
requested classification and change in 
classification. 
    The Panel reviewed complication type and 
rate data present in the literature, a 
meta-analysis of the literature; a 
nationwide, retrospective Cohort study of 
patients treated with the devices;\1\ and a 
review of publicly released investigational 
device exemptions (IDE) data from patients 
treated with pedicle screw spinal systems. 
The Panel recommended that the postamendments 
pedicle screw spinal systems intended to 
treat spinal fracture and degenerative 
spondylolisthesis of the thoracic, lumbar, 
and sacral spine, be reclassified from class 
III into class II. 
---------------------------------------------
--------------- 
    \1\ The Cohort study was an open, 
nonblinded, historical Cohort study designed 
to recruit the maximum number of surgeons to 
provide clinical data on patients who had 
undergone spinal fusion surgery. Three 
hundred fourteen surgeons were recruited 
through announcements at professional society 
meetings and direct mailings to professional 
society memberships. Only clinical data from 
spinal fusion surgeries intended to treat 
degenerative spondylolisthesis or spinal 
trauma (fracture) that were performed between 
January 1, 1990, and December 31, 1991, were 
used in the analysis. This was done in an 
effort to maximize the number of patients 
with a minimum of 24 months followup. Data 
from 3,498 patients were collected. 
---------------------------------------------
--------------- 
    In January, 1995, a manufacturer was able 
to demonstrate 
preamendments status for pedicle screw spinal 
systems intended to provide immobilization 
and stabilization of spinal segments as an 
adjunct to spinal fusion in the treatment of 
grades 3 or 4 severe spondylolisthesis at the 
fifth lumbar-first sacral (L5- 
S1) spinal level. In an April 
1995, homework assignment, FDA requested that 
the Panel recommend a classification for this 
unclassified preamendments device. The Panel 
recommended that the unclassified 
preamendments pedicle screw spinal systems 
intended to provide immobilization and 
stabilization of spinal segments as an 
adjunct to spinal fusion in the treatment of 
grades 3 or 4 severe spondylolisthesis at the 
L5-S1 spinal level be 
classified into class II. 
  In the Federal Register of October 4, 1995 
(60 FR 51946), FDA published a proposed rule 
to classify certain unclassified 
preamendments pedicle screw spinal systems 
(for use in certain types of severe 
spondylolisthesis ) into class II, to 
reclassify certain postamendments pedicle 
screw spinal systems (for use in fracture and 
other conditions) from class III to class II, 
and to retain in class III other 
postamendments pedicle screw spinal systems. 
The proposed rule reflected FDA's belief that 
the clinical outcomes and 
complications described in the literature, 
clinical data, and MDR and MedWatch 
surveillance data bases,\2\ described patient 
risks and benefits of pedicle screw spinal 
systems comparable to other class II spinal 
fixation devices and that special controls 
have been identified which would provide a 
reasonable assurance of safety and 
effectiveness, 
i.e., compliance with material standards, 
mechanical testing standards, 
biocompatibility standards, and special 
labeling requirements. Initially, FDA 
provided for interested persons to submit 
comments on the proposal by January 2, 1996. 
Subsequently, in the Federal Register of 
December 29, 1995 (60 FR 67345), FDA extended 
the comment period until March 4, 1996, in 
response to several requests for extension of 
the comment period. 
---------------------------------------------
--------------- 
    \2\ MDR and MedWatch data bases are two 
reporting systems that FDA uses to track 
adverse events, e.g., injuries, deaths, and 
device malfunctions, related to medical 
devices. The information consists of a 
combination of mandatory and/or voluntary 
adverse event reports from manufacturers, 
distributors, user facilities, healthcare 
professionals, as well as consumers. 
---------------------------------------------
--------------- 
    FDA received 4,060 comments in response 
to the proposed rule. These comments were 
submitted by physicians, patients, lawyers, 
device manufacturers, trade associations, and 
other interested parties. The overwhelming 
majority of these comments were in favor of 
the proposed rule, although some comments 
were opposed to the proposed rule, and a few 
were both in favor of some aspects of the 
proposed rule and opposed to others. 
    In response to comments received on the 
proposed rule, FDA reanalyzed the 
meta-analysis of the literature, the Cohort 
study, and the publicly released IDE data for 
the indications of spinal fractures and 
degenerative spondylolisthesis. The 
reanalysis of the meta-analysis of the 
literature consisted of a review of the 
summary data and conclusions from the 
original, published analysis. The review of 
the Cohort study consisted of an audit (Ref. 
1) of a structured sample of all 377 patients 
enrolled by 21 of the 314 participating 
surgeons, a reanalysis (Ref. 2) of all of the 
data from the audit, and a comparison to the 
data from unaudited surgeons. The Division of 
Bioresearch Monitoring (BIMO) in the Office 
of Compliance performed the data audit, while 
the Office of Device Evaluation and the 
Office of Surveillance and Biometrics 
performed the reanalyses. This audit found 
records were incomplete and investigators had 
not followed the protocol. In review of the 
audit, the agency concluded that the 
disparities and irregularities were 
consistent, with respect to both type and 
scope, with other audits of similar studies. 
After careful reanalysis of the potential 
impact of the ``problem创 records, the agency 
concluded that they could not account for the 
favorable results reported in this study. 
    The review of the Cohort study in the 
context of the audit findings yielded results 
that supported the safety and effectiveness 
of these devices. For spinal fracture, 
pedicle screw spinal systems presented risks 
and benefits that were comparable to those 
presented by nonpedicle screw instrumented 
spinal fusion. The devices used in the 
comparison group are class II medical 
devices. For spondylolisthesis, the review in 
the context of the audit findings described 
an advantage for pedicle screw spinal systems 
with regard to the clinical outcome 
parameters of fusion and improvement in 
neurological status when compared to 
noninstrumented spinal fusions. For the other 
parameters that were analyzed, e.g., pain, 
function, and reoperation rate, pedicle screw 
spinal systems did not always demonstrate an 
advantage compared to noninstrumented spinal 
fusion. When compared to instrumented spinal 
fusions, however, results among pedicle screw 
spinal system patients for these parameters 
were not statistically equivalent and not 
worse. Thus, FDA has concluded that the 
results from the review of the Cohort study 
are consistent with those reported in the 
literature and the publicly released IDE 
data. 
    The reanalysis of the meta-analysis of 
the literature describing experience with 
pedicle screw spinal systems in treating 
spinal fracture and degenerative 
spondylolisthesis found that pedicle screw 
spinal systems present risks and benefits 
that are comparable to those presented by 
nonpedicle screw spinal systems and 
noninstrumented spinal fusions. For 
degenerative spondylolisthesis, the 
reanalysis found 
[[Page 40027]] 
that patient results with pedicle screw 
spinal systems were comparable to those with 
noninstrumented spinal fusions; it did not 
find a clinically significant improvement in 
results at followup obtained with 
instrumented spinal fusions over 
noninstrumented spinal fusions. 
    The reanalysis of the publicly available 
IDE data supports the Panel's recommendation 
for the classification and reclassification 
of pedicle screw spinal systems intended to 
treat spinal fractures and severe 
spondylolisthesis. It also supports the use 
of pedicle screw spinal systems when intended 
to provide immobilization and stabilization 
of spinal segments in skeletally mature 
patients as an adjunct to fusion for the 
treatment of the following acute and chronic 
instabilities or deformities of the thoracic, 
lumbar, and sacral spine: degenerative 
spondylolisthesis with objective evidence of 
neurologic impairment, fractures, 
dislocations, scoliosis, kyphosis, spinal 
tumors, and failed previous fusion 
(pseudarthrosis). 
    When all of these data are viewed in 
conjunction with the medical literature and 
the MDR and MedWatch surveillance data, no 
new issues relating to the safety or 
effectiveness of pedicle screw spinal systems 
are raised. Therefore, the agency has 
concluded that these data provide valid 
scientific evidence that certain special 
controls in conjunction with the general 
controls applicable to all devices, will 
provide a reasonable assurance of the safety 
and effectiveness of pedicle screw spinal 
systems for L5-S1 use 
and for use at other levels for the treatment 
of degenerative spondylolisthesis with 
objective evidence of neurologic impairment. 
    The agency also reviewed whether the 
Panel was properly 
constituted. Investigation of alleged 
undisclosed and unwaived conflicts of 
interest held by Panel members found either 
no omissions of current interests or 
omissions of minor interests for all but one 
of the Panel members. The agency has 
concluded that the minor omissions are 
insignificant and do not constitute a 
financial conflict of interest that would 
credibly influence the members' actions in 
forming the Panel's recommendations. 
  The agency has found that one voting Panel 
member did have 
significant undisclosed financial conflicts. 
However, because the recommendation of the 
Panel, both in the July 23, 1994, meeting and 
on the subsequent homework assignment, was 
unanimous and this individual was not 
controlling, or unduly influential, of the 
votes of the other Panel members and was not 
necessary to constitute a quorum, after 
expunging the participation of this Panel 
member, FDA has concluded that this Panel, 
both in the meeting and on the subsequent 
homework assignment, was a valid scientific 
Panel to make recommendations to the agency. 
    The agency's reanalysis of these data has 
confirmed its original conclusion, reflected 
in the proposed rule, that the risks and 
benefits of pedicle screw spinal systems are 
comparable to those of other class II spinal 
fixation devices. FDA's decision to classify 
and reclassify these devices into class II is 
based upon valid scientific evidence 
establishing that the special controls 
described above, along with the general 
controls applicable to all devices under the 
act, provide a reasonable assurance of the 
safety and effectiveness of pedicle screw 
spinal systems. 
III. Summary of the Final Rule 
    In this final rule, FDA is classifying 
into class II the 
unclassified preamendments pedicle screw 
spinal systems intended for treatment of 
severe spondylolisthesis (grades 3 and 4) of 
the L5-S1 vertebra in 
skeletally mature patients receiving fusion 
by autogenous bone graft having implants 
attached to the lumbar and sacral spine with 
removal of the implants after the attainment 
of a solid fusion. In addition, FDA is 
reclassifying into 
class II the postamendments class III pedicle 
screw spinal systems intended to provide 
immobilization and stabilization of spinal 
segments in skeletally mature patients as an 
adjunct to fusion in the treatment of the 
following acute and chronic instabilities or 
deformities of the thoracic, lumbar, and 
sacral spine: Degenerative spondylolisthesis 
with objective evidence of neurologic 
impairment, fracture, dislocation, scoliosis, 
kyphosis, spinal tumor, and failed previous 
fusion (pseudarthrosis). Pedicle screw spinal 
systems intended for any other uses are 
considered postamendments class III devices 
for which premarket approval is required. The 
following four special controls apply to the 
devices being classified and reclassified 
into class II: (1) Compliance with materials 
standards, (2) compliance with mechanical 
testing standards of performance, (3) 
compliance with biocompatibility standards, 
and (4) adherence to labeling requirements. 
IV. Proposed Rule Clarifications 
  FDA is taking this opportunity to clarify 
that neither well- controlled investigations 
nor valid scientific evidence relating to 
pedicle screw spinal systems intended for use 
in the cervical spine is available and, 
therefore, the safety and effectiveness of 
these devices for this intended use have not 
been demonstrated. As a result, pedicle screw 
spinal systems intended for use in the 
cervical spine are excluded from this 
classification and reclassification and are 
considered postamendments class III devices 
for which premarket approval is required. 
    In addition, although not specifically 
stated in the preamble to the proposed rule, 
all valid scientific evidence reviewed by the 
Panel and FDA were obtained from skeletally 
mature populations. To date, the safety and 
effectiveness of pedicle screw spinal systems 
in pediatric populations have not been 
demonstrated. Consequently, pedicle screw 
spinal systems intended for use in pediatric 
populations are postamendments class III 
devices for which premarket approval is 
required. 
V. Analysis of Comments and FDA's Response 
A. Issues Relating to the Recommendations of 
the Panel, FDA's Tentative Findings, and 
Summary of the Data Upon Which FDA's Findings 
Were Based 
    1. Several comments believed that valid 
scientific evidence was not presented to the 
Panel or used in formulating the proposed 
rule. These comments argued that only 
prospective, randomized, concurrently- 
controlled clinical trials constitute valid 
scientific evidence and that anything else is 
insufficient to support device 
reclassification. 
  FDA disagrees that only data from 
prospective, randomized, 
concurrently-controlled clinical trials can 
constitute valid scientific evidence. 
Although prospective, randomized, 
concurrently controlled clinical trials have 
the potential to produce the most convincing 
and reliable data, e.g., all sources of bias 
have been reduced to a minimum, such clinical 
trials are not the only type of study that 
can produce data adequate to support a 
determination that there is reasonable 
assurance that a device is safe and effective 
for its conditions for use. In fact, Sec. 
860.7(c)(2) defines valid scientific evidence 
as 
  * *evidence from well-controlled 
investigations, partially 
controlled studies, studies and objective 
trials without matched controls, 
well-documented case histories conducted by 
qualified experts, and reports of significant 
human experience with a marketed device, from 
which it can fairly and responsibly be 
concluded by qualified experts that there is 
reasonable assurance of the safety and 
effectiveness of a device under 
[[Page 40028]] 
its conditions of use. The evidence may vary 
according to the characteristics of the 
device, the existence and adequacy of 
warnings and other restrictions, and the 
extent of experience with 
its use * * *. 
From this definition, it is clear that there 
is a hierarchy of data that fits the 
definition of valid scientific and that, 
while well- controlled, prospective clinical 
trials are at the top of the hierarchy, they 
are not the only source of data that may 
support a determination regarding reasonable 
assurance of safety and effectiveness for 
purposes of classifying and/or reclassifying 
a device. 
    FDA also disagrees that valid scientific 
evidence was not presented to the Panel or 
used in support of the proposed rule. The 
three sources of data presented to the Panel 
and used in support of the proposed rule 
were: (1) Reformatted IDE data, (2) a 
meta-analysis of the literature, and (3) the 
Cohort study. The reformatted IDE data 
represent data from well-controlled 
investigations, while the meta-analysis of 
the literature and the Cohort study represent 
studies and objective trials without matched 
controls or well-documented case histories or 
reports of significant human experience. All 
three sources of data used in support of the 
classification and reclassification of 
pedicle screw spinal systems clearly fall 
within the definition of valid scientific 
evidence in Sec. 860.7(c)(2). 
  2. One comment objected that, in addition 
to not being valid scientific evidence, the 
three sources of data, i.e., the 
meta-analysis of the literature, the 
reformatted IDE data and the Cohort study, 
were flawed. 
  The comment noted the following 
deficiencies with the meta- analysis: 
      FDA previously determined that 
the available literature on pedicle screw 
spinal systems could not be used to support 
device reclassification. 
    FDA disagrees. FDA made that statement 
prior to January, 1993, when no adequate 
analysis of pedicle screw literature had been 
provided to the agency. FDA believes that, 
while individual literature articles 
describing the use of pedicle screw spinal 
systems would be insufficient to support 
reclassification of a device, group analysis 
of relevant articles may be adequate, 
especially where, as here, the group analysis 
is considered in conjunction with other 
supporting data. Furthermore, after noting 
the limitations of the individual studies 
reported in the literature, FDA concluded 
that the literature, taken as a whole and 
used in conjunction with the other sources of 
data, provided adequate information to 
support the reclassification of pedicle screw 
spinal systems intended to treat degenerative 
spondylolisthesis with objective evidence of 
neurologic impairment or spinal trauma. 
    The meta-analysis is not an 
appropriate scientific technique, as applied 
to retrospective studies, because different 
studies have different parameters, biases, 
and strengths and weaknesses, all of which 
invalidate the pooling of data. 
    FDA disagrees. Although meta-analysis of 
literature may be less rigorous than other 
forms of scientific research, it still 
provides useful information. As discussed in 
section V.A.1 of this document, Sec. 
860.7(c)(2) defines ``valid scientific 
evidence创 to include many types of evidence 
of varying degrees of scientific rigor, 
including meta-analysis of literature. FDA 
participated in the development of the 
meta-analysis because the agency believed 
that this analysis could produce data meeting 
the definition of valid scientific evidence. 
Finally, the inherent limitations of a 
literature meta-analysis were discussed 
during the presentation of this analysis at 
the July 23, 1994, Panel meeting and in the 
preamble to the proposed rule (60 FR 51946). 
      The meta-analysis actually lent 
support to the conclusion that pedicle screw 
fixation is less effective than other methods 
of treating degenerative spondylolisthesis 
and spinal fracture and that it may present 
the patient with more risks. 
    FDA disagrees. With respect to 
degenerative spondylolisthesis, there was no 
statistically significant difference in 
fusion rates between the control and the 
pedicle screw spinal system treatment groups. 
This is supportive data that clarifies the 
relative safety and effectiveness of pedicle 
screw spinal systems for this use. With 
respect to spinal fracture, significantly 
higher fusion rates were achieved in the 
pedicle screw spinal system treatment group 
than in the nonpedicle screw treatment 
groups. Thus, the meta-analysis confirmed the 
comparability of pedicle screw spinal systems 
to other class II devices used to treat 
spinal fracture in terms of safety and 
effectiveness. 
      Fifty-five of the 58 studies in 
the meta-analysis were nonexperimental 
case-series having no validity as scientific 
evidence. 
    FDA disagrees. As discussed in section 
V.A.1 of this document, Sec. 860.7(c)(2) 
states that valid scientific evidence may 
include ``* 
* * well-documented case histories conducted 
by qualified experts * * 
*''. Moreover, these well-documented case 
studies, which were conducted by qualified 
experts, were not the sole basis for the 
proposed classification/reclassification, but 
rather were considered in conjunction with 
data from various other sources. 
  The comment also noted the following 
deficiencies with the 
reformatted IDE data: 
    The reformatted IDE data are not 
appropriate for 
classifying and reclassifying pedicle screw 
spinal systems because FDA 
previously had determined that these data 
could not support PMA's for these devices. 
    FDA disagrees in part. Prior to the 
August 20, 1993, Panel meeting, FDA had 
determined that data from individual IDE's 
were insufficient to support PMA's for those 
devices. Nevertheless, FDA recognized that 
the IDE data could still be valuable. In 
1993, after receiving permission from nine 
IDE sponsors to publicly release and use 
their combined data, FDA determined that the 
data, reviewed as a whole, corroborated the 
results of other available data sets 
demonstrating the safety and effectiveness of 
pedicle screw spinal systems. 
      The reformatted IDE data are 
inherently suspect because they (1) were 
reformatted by the sponsors and not by FDA, 
(2) were not provided for public scrutiny 
during the Panel meeting or at any other 
time, and (3) may have omitted poor results. 
    FDA disagrees that the reformatted data 
were suspect because they were reformatted by 
the sponsors and not by FDA. If IDE data are 
not properly formatted, FDA requests the 
sponsor to reformat its data for proper 
presentation to the agency. Furthermore, data 
in all marketing applications are formatted 
by the sponsor. Therefore, the simple fact 
that the IDE data were reformatted by the 
sponsor, not by FDA, does not 
make these data inherently suspect. 
    FDA also disagrees that the data were 
suspect because they were not presented for 
public scrutiny. For reclassification 
purposes, the valid scientific evidence upon 
which the agency relies must be publicly 
available Sec. 860.5(e) (21 CFR 860.5(e)). 
Publicly available information excludes trade 
secret and/or confidential commercial 
information (21 CFR 20.61). IDE data 
typically contain trade secret and/or 
confidential commercial information and, 
consequently, ordinarily may not be publicly 
disclosed by the agency to support 
reclassification of a device (49 FR 17523 at 
17531 and 17532, April 24, 1984). In fact, 
under Sec. 812.38(a) and (b)(3) (21 CFR 
812.38 (a) and (b)(3)), FDA generally does 
not acknowledge the existence of an IDE or 
disclose any 
[[Page 40029]] 
of the collected data. However, on August 13, 
1993, after receiving permission from nine 
IDE sponsors to publicly release and use 
their combined data, the Commissioner of Food 
and Drugs (the Commissioner) exercised his 
discretionary authority under Sec. 
812.38(b)(2) and publicly released the data 
from nine IDE's, redacted of the 
identification of the IDE sponsors, 
institutional review boards, investigators, 
and patients. Although FDA did not make 
publicly available the unformatted data from 
the IDE studies or the identification of the 
IDE sponsors, institutional review boards, 
investigators or patients, the agency did 
provide the public with a detailed report of 
the combined IDE data (60 FR 51946 at 51961, 
ref. 
173). This information was publicly available 
for analysis for more than 2 years before the 
publication of the proposed rule. 
    Finally, FDA disagrees that the data were 
suspect because they may have omitted poor 
results. Nine of fourteen sponsors provided 
their reformatted IDE data for analysis. 
There is no evidence that the five sponsors 
who did not offer their data did so because 
the data reflected adversely on the 
performance of their products. They may not 
have provided their data for any number of 
reasons. For instance, the sponsors may have 
believed that they had an inadequate amount 
of data to contribute to the effort or that 
the data may not have been in a readily 
accessible format. Regardless of the reason, 
the publicly available reformatted IDE data 
corroborate the results of other studies that 
demonstrate the safety and effectiveness of 
pedicle screw spinal systems. Specifically, 
the fusion rates, complication rates, and 
reoperation, revision, and removal rates 
attained under publicly available IDE studies 
were consistent with what was observed in the 
literature for such devices. 
      The 12-month followup time 
period was inadequate to support any 
conclusions. Specifically, the comment stated 
that the Panel was not supplied with any 
information on the safety and effectiveness 
of these devices at more than 1 year 
following surgery. The comment continued 
that, without a minimum followup period of 2 
years, it is impossible to make appropriate 
conclusions with regard to the longer-term 
safety and efficacy of these devices in 
accordance with accepted scientific 
convention. 
    FDA agrees that a 12-month followup time 
period would be inadequate and, therefore, 
selected a 24-month followup period for 
analysis. The 
24-month followup period was also supported 
by the Panel and the literature. Contrary to 
the comment's statement, the Panel was 
supplied with information on the safety and 
effectiveness of pedicle screw spinal systems 
at more than one year following surgery. 
Spinal fusion generally occurs within 6 to 18 
months after surgery. The majority of 
post-operative complications occur by the 
18th month time point. For these reasons, FDA 
concluded that a 24-month followup period was 
adequate. FDA recognizes that not all of the 
reformatted IDE data were from a 24-month 
followup examination. However, a sufficient 
amount of data from a 24 month followup 
evaluation was examined for the Panel to make 
a recommendation about the reasonable 
assurance of safety and effectiveness of 
pedicle screw spinal systems for their class 
II intended uses. 
      The comment stated that the 
lost-to-followup rate was too high. 
    FDA agrees that the lost-to-followup rate 
was high. FDA believes that patients with 
poor results tend to either return to their 
surgeons more frequently or go to other 
caregivers, attempting to receive the pain 
relief and return of function that they were 
originally seeking. It cannot be determined 
whether the patients who were 
lost-to-followup had acceptable results or 
went to other caregivers. However, FDA does 
not believe that this theoretical weakness in 
the data is of such a magnitude as to justify 
rejecting the studies. Thus, both the Panel 
and FDA believe that the lost-to-followup 
rate was not unacceptably high. 
    The comment noted the following 
deficiencies with the Cohort study:   
The Cohort study did not constitute valid 
scientific 
evidence. 
  FDA disagrees. As described above, valid 
scientific evidence encompasses a wide 
variety of data. The Cohort study satisfies 
the definition of valid scientific evidence 
because it consisted of data from 
well-documented case histories conducted by 
qualified experts and reports of significant 
human experience. 
      The sample size and statistical 
power used in designing the Cohort study were 
inadequate and, therefore, no reliable 
conclusions can be drawn from the study. 
Another comment attempted to rebut this 
allegation. 
    FDA believes that the sample size and 
statistical power 
calculations that were performed in the 
Cohort study were accurate and appropriate 
and, consequently, that the conclusions drawn 
from the study had a sound basis. 
    The Cohort study was biased and 
the data were not independently audited. 
    FDA disagrees. While the potential for 
bias exists in any study, it was of 
particular concern in the design of the 
Cohort study due to its retrospective nature. 
As described at the July 22, 1994, Panel 
meeting and in the preamble to the proposed 
rule (60 FR 51946 at 51954), various steps 
were taken to minimize the potential effects 
of bias due to the study design. In addition, 
contrary to the comment's assertion, there 
was a review of the data by an independent 
auditor and a subsequent FDA BIMO audit and 
review. The review by the independent auditor 
was not extensive and no definitive 
conclusions can be drawn from its analysis of 
the Cohort study data. Although both audits 
uncovered instances of protocol departures, 
recordkeeping inconsistencies, or a lack of 
clear understanding or unfamiliarity with the 
protocol requirements on the part of a 
participating surgeon, these inconsistencies 
and protocol departures did not affect the 
reliability of the data. For example, one 
type of reported protocol recordkeeping 
departure was that some data forms were 
incomplete. In some instances, the data forms 
simply omitted the patient's weight, but not 
the patient's fusion status. The absence of 
that piece of information, while rendering 
the form incomplete, clearly did not affect 
the clinical outcome analysis. A more 
significant protocol departure related to the 
inclusion and analysis of data from patients 
whose diagnosis did not meet patient 
eligibility criteria. However, no obvious 
pattern that would improve overall patient 
outcomes was identified because these 
departures included indications for surgery 
both more and less severe than those targeted 
by the protocol. 
    The data retrieved from the BIMO audit 
were analyzed to determine if the major 
outcomes of the Cohort study were 
significantly different (statistically or 
clinically) with or without the presence of 
protocol departures, with or without the 
presence of recordkeeping inconsistencies, or 
at sites where the participating 
investigator, based on the audit, was or was 
not familiar with the protocol requirements. 
While some differences were noted between 
sites with and without inconsistencies, in 
most cases, these were not statistically 
significant and no consistent or clinically 
relevant patterns were noted. The analysis of 
the audited data did not find systemic bias 
in either the conduct of the study or its 
reported results. None of the analyzed audit 
data contradicted the published results of 
the Cohort study. Finally, the data audit 
analysis concluded that the audited data were 
consistent with other publicly available 
[[Page 40030]] 
data and that the Cohort study data could be 
used as part of a larger body of data to 
support the classification and 
reclassification of pedicle screw spinal 
systems. 
      Documents relating to the 
Cohort study were destroyed. 
    FDA disagrees. All Cohort study data were 
maintained in a master file. Only extra 
copies of information were destroyed in an 
effort to maintain the confidentiality of the 
identities of the participating surgeons and 
their patients. In addition, as a matter of 
course, FDA routinely assists Panel members 
in destroying copies of documents containing 
trade secret and/or confidential commercial 
information that they have received from FDA 
as preparatory material for a Panel meeting. 
      Certain FDA employees had 
inappropriate relationships with pedicle 
screw manufacturers and others involved in 
the Cohort study. 
    This allegation, which has two parts, is 
unfounded. FDA performed an internal affairs 
investigation of the employees about whom 
allegations were made. This investigation 
showed that their attendance at a health 
professional meeting was properly paid for by 
the agency, not subsidized by the regulated 
industry. Also in the case of one employee, 
FDA's investigation showed that negotiations 
regarding outside employment with the 
regulated industry had been properly reported 
to the employee's supervisors and immediate 
colleagues in all instances. 
     The Scientific Committee and the 
Spinal Implant 
Manufacturers Group (SIMG) were not 
independent. 
    FDA disagrees. The preamble to the 
proposed rule and the subsequent correction 
(60 FR 51946 and 60 FR 66227, December 21, 
1995) described the makeup of the Scientific 
Committee and SIMG. SIMG consisted of 
representatives of manufacturers who provided 
funding to support a nationwide analysis of 
clinical data relating to pedicle screw 
spinal systems. SIMG did not participate in 
the design of the study. The study was 
designed and implemented by the Scientific 
Committee with input from FDA as to the 
feasibility of various clinical study design 
parameters. The Scientific Committee was 
formed by five professional medical 
societies. Although two SIMG representatives 
were part of the Scientific Committee, they 
were nonvoting members. Furthermore, even if 
there were not independence between the 
Scientific Committee and SIMG, there is no 
requirement that clinical studies be 
performed by parties independent of device 
manufacturers. In fact, FDA routinely 
receives and relies upon studies performed by 
manufacturers. 
    3. Several comments contended that 
financial conflicts of interest were present 
in the three sources of data relied on by FDA 
to support 
the classification/reclassification of 
pedicle screw spinal systems. The comments 
claimed that, in the meta-analysis of the 
literature, the authors of the individual 
articles had financial conflicts of interest 
due to their relationships with device 
manufacturers. With respect to the analysis 
of the reformatted IDE data and the Cohort 
study, the comment stated that the IDE 
investigators and Cohort study participants 
had significant financial interests in the 
companies whose devices they were using and, 
therefore, had a strong financial incentive 
to report only successful results. Similar 
objections were raised about the authors of 
the 206 articles cited as constituting the 
body of medical literature bearing on pedicle 
screw fixation. The comments stated that 
almost all of the surgeons who authored these 
articles failed to disclose their financial 
connections to manufacturers. The comments 
stated that such interests raise serious 
concerns about researchers' motivation to 
perform the research, the propriety and 
importance of research questions and research 
designs, the adequacy of protection of human 
subjects, lack of bias, and veracity in 
collecting and analyzing the data and 
reporting the results. 
    FDA recognizes that some of the clinical 
investigators involved in the three sources 
of data, as well as some of the authors of 
the 206 literature articles used to support 
classification and reclassification of 
pedicle screw spinal systems, had financial 
interests in the devices they were studying. 
FDA disagrees, however, that these financial 
interests resulted in biased or unreliable 
data. Regardless of the source of the data, 
the meta-analysis, the reformatted IDE data, 
the Cohort study, or the collection of cited 
literature, the conclusions were similar, 
i.e., that pedicle screw spinal systems are 
safe and effective for the uses examined. 
Because of this, even if financial conflicts 
of interest were present, they did not affect 
the resulting data and the conclusions. 
Moreover, the agency has concluded that, 
despite the failure to disclose the financial 
interests of clinical investigators, the 
sponsors of these investigations and/or 
articles took reasonable steps to minimize 
potential bias. 
    Furthermore, the fact that some spine 
surgeons were compensated by industry for 
research or consulting services, or were 
reimbursed for expenses incurred in 
connection with continuing medical education 
courses, did not affect the validity of any 
of the data. Moreover, many of the grants to 
support research were made directly to 
university accounts for general research and 
development, not directly to individual 
investigators. Consequently, the existence of 
a financial relationship between some 
surgeons and manufacturers did not 
necessarily result in biased case selection 
or reporting. Finally, FDA 
notes that research used to support a medical 
device marketing application has always been 
supported by the sponsor of the device and 
there is neither an expectation of nonsupport 
nor a requirement of disclosure of such 
support. 
  4. Several comments stated that pedicle 
screw spinal systems present different safety 
and effectiveness issues than do either class 
II spinal devices using hooks and/or wires or 
noninstrumented spinal fusions. One comment 
identified the following areas of concern as 
having the potential of presenting 
unreasonable danger for patients: 
    (1) Difficulty in placing screws 
completely within the walls of the pedicle; 
    (2) Inability to determine screw 
placement postoperatively using radiographic 
techniques; 
    (3) Damage to nerve tissue as a result of 
transient contact with a screw during screw 
placement; 
    (4) Nerve root damage (irritation or 
compression) as a result of screw 
malposition; 
    (5) Device failure; 
    (6) Loss of bone density as a result of 
stress shielding; (7) Foreign body tissue 
response; 
    (8) Crevice corrosion; 
    (9) Fretting corrosion; 
    (10) Fibrosis; 
    (11) Bone fracture, particularly that of 
the pedicles; 
    (12) Nerve root or spinal cord 
compression as a result of fibrosis or 
foreign body tissue response; 
    (13) Chronic irritation; 
    (14) Spine destabilization possibly 
leading to nonunion; 
  (15) Increased venous pressure as a result 
of blocked venous channels within the bone; 
    (16) Increased risk of infection; 
    (17) Loss or decrease of sensory and/or 
motor function; 
    (18) Loss of bowel or bladder control; 
and 
    (19) Loss of sexual function. 
    FDA agrees that pedicle screw spinal 
systems have some potential risks that 
[[Page 40031]] 
are different from those of other class II 
spinal devices. However, the majority of the 
potential risks presented by these devices, 
e.g., bone fracture, foreign body tissue 
response, loss or decrease in sensory and/or 
motor function, and device failure or 
corrosion, are also associated with class II 
spinal devices which use hooks and/or wires 
for the same intended uses. Similarly, 
potential risks such as nonunion and 
instability are also associated with 
noninstrumented spinal fusions. Moreover, as 
described in the proposed rule, the incidence 
of these adverse outcomes is no greater when 
a pedicle screw spinal system is used than 
when other types of spinal fusions, 
instrumented and noninstrumented, are 
performed in appropriately selected patients 
(60 FR 51946 at 51957). Finally, FDA believes 
that the potential risks that are unique to 
pedicle screw spinal systems, e.g., 
difficulty in placing screws completely 
within the walls of the pedicle, inability to 
determine screw placement postoperatively 
using radiographic techniques, damage to 
nerve tissue as a result of transient contact 
with a screw during screw placement, and 
nerve root damage (irritation or compression) 
as a result of screw malposition, can be 
adequately addressed by the identified 
special controls and proper surgeon training 
and surgical technique. 
    5. One comment asserted that the supposed 
advantages of pedicle screw spinal systems 
are largely theoretical. The comment stated 
that, while some investigators have shown 
that instrumented fusions increase the 
likelihood of obtaining a solid fusion, 
others have demonstrated that there is no 
significant increase in fusion rates 
performed with instrumentation as compared 
with noninstrumented fusions performed with 
bone graft alone. 
    FDA agrees that the data do not always 
support the theoretical advantages of using 
pedicle screw spinal systems compared to 
alternate methods of achieving spinal fusion. 
However, in forming its recommendations, 
neither FDA nor the Panel is required to 
analyze the theoretical behavior of a given 
device. It is only required to determine 
whether the data demonstrate that there is a 
reasonable assurance of safety and 
effectiveness for its intended uses. 
    6. The same comment stated that spinal 
fusion surgery is usually performed because 
of the belief that spinal instability results 
in pain. The clinical indicators used to 
determine which patients have spinal 
instability and, therefore, are candidates 
for spinal fusion surgery, are not clearly 
defined and are often not measurable. Because 
the results of spinal fusion surgery are also 
dependent on measurements of instability, a 
determination of success is difficult, if not 
impossible. 
    FDA agrees that the methods used to 
measure instability are not perfect and that 
several working definitions of instability 
exist. Nevertheless, instability is 
measurable. In addition, the same instability 
definitions and measurement techniques are 
used in determining how a patient is to be 
treated, i.e., with pedicle screw spinal 
systems, class II spinal devices using hooks 
and/or wires, or noninstrumented fusions. FDA 
agrees that the determination of success of 
spinal fusion surgery is often difficult, but 
disagrees that it is impossible to determine. 
In fact, the success rates from using the 
three treatment methods described above have 
been determined and found to be reasonably 
equivalent (60 FR 51946 at 51954). 
    7. Three comments questioned the most 
appropriate classification for pedicle screw 
spinal systems. One comment proposed that 
pedicle screw spinal systems be classified 
into class I and two comments suggested 
placing them in class III. 
    FDA disagrees. Based on the available 
information, both the Panel and FDA concluded 
that general controls alone are not 
sufficient to provide a reasonable assurance 
of the safety and effectiveness of pedicle 
screw spinal systems intended to provide 
immobilization and stabilization of spinal 
segments as an adjunct to fusion in the 
treatment of the following acute and chronic 
instabilities or deformities of the thoracic, 
lumbar, and sacral spine: Degenerative 
spondylolisthesis with objective evidence of 
neurologic impairment, fractures, 
dislocations, scoliosis, kyphosis, spinal 
tumors, and failed previous fusion attempts 
(pseudarthrosis). The Panel and FDA also 
concluded that premarket approval was not 
necessary to provide such assurance. Both the 
Panel and FDA identified the potential risks 
associated with the use of these devices and 
concluded that sufficient information exists 
to establish special controls to provide 
reasonable assurance of their safety and 
effectiveness. As a result, FDA is 
classifying and reclassifying these devices 
in class II. 
    8. A comment believed that classification 
and reclassification of pedicle screw spinal 
systems into class II is inappropriate 
because FDA 
was correct in its prior determination that 
basic principles of physiology, anatomy, 
biology, and biomechanical engineering 
demonstrate that pedicle screw spinal systems 
present a serious risk of injury to the 
spinal nerves, nerve roots, and surrounding 
vascular structures, and increase the risk of 
pseudarthrosis. According to this comment, 
these risks are not posed by existing spine 
fusion technology and pedicle screw spinal 
systems are of questionable efficacy in 
comparison to existing methodologies of 
treatment. 
    FDA disagrees. FDA did not determine that 
basic principles of physiology, anatomy, 
biology, and biomechanical engineering 
demonstrate that pedicle screw spinal systems 
present a serious risk of injury. Rather, in 
1984, FDA determined that a multiple 
component device system intended for 
attachment to the spine via the pedicles was 
not substantially equivalent to any legally 
marketed predicate device, in accordance with 
section 513(i)(1) of the act. FDA's decision 
was based on the fact that: (1) The sponsor 
did not identify a legally marketed 
preamendments device incorporating pedicle 
screw components and (2) the device posed 
potential risks not exhibited by other 
legally marketed predicate spinal fixation 
systems, such as a greater chance of 
neurological deficit due to imprecise screw 
placement or the event of a screw failure; 
pedicle fracture during placement of screws; 
soft tissue damage or inadequate fusion due 
to bending or fracture of device components; 
and greater risk of pseudarthrosis due to 
instability of the device design (60 FR 51946 
at 51947). As stated previously, FDA 
believes that the risks to health presented 
by pedicle screw spinal systems intended to 
provide immobilization and stabilization of 
spinal segments as an adjunct to fusion in 
the treatment of the following acute and 
chronic instabilities or deformities of the 
thoracic, lumbar, and sacral spine: 
Degenerative spondylolisthesis with objective 
evidence of neurologic impairment, fractures, 
dislocations, scoliosis, kyphosis, spinal 
tumors, and failed previous fusion 
(pseudarthrosis) can be adequately addressed 
by special controls. Consequently, FDA is 
classifying and reclassifying these devices 
into class II. 
    9. One comment argued that manufacturers 
of pedicle screw spinal systems are seeking 
to have FDA down classify the device into 
class II because the manufacturers are unable 
to prove that pedicle screws are safe and 
effective for posterior implantation into the 
spine. 
    FDA disagrees. First, contrary to the 
comment's statement, this classification and 
reclassification proceeding was 
[[Page 40032]] 
initiated by FDA; it is not in response to a 
petition for 
reclassification. Second, under section 513 
of the act, devices are 
classified/reclassified into one of three 
classes based on reasonable assurance, not 
``absolute proof,创 of their safety and 
effectiveness. Contrary to the comment's 
statement, it was not pedicle screw spinal 
system manufacturers, but rather the Panel 
and FDA, that concluded that pedicle screw 
spinal systems should be classified and 
reclassified into class II because they 
determined that premarket approval is not 
necessary to provide reasonable assurance of 
the device's safety and effectiveness, 
general controls alone are insufficient to 
provide such assurance, and there is 
sufficient information to establish special 
controls to provide such assurance. 
    10. According to another comment, by 
classifying and reclassifying pedicle screw 
spinal systems into class II, FDA is 
acknowledging that 
there is no need for the manufacturers of 
pedicle screw spinal systems to prove that 
the devices are safe and effective. 
    FDA agrees. The agency has determined 
that sufficient information exists to 
establish special controls to provide 
reasonable assurance of the safety and 
effectiveness of pedicle screw spinal systems 
intended to provide immobilization and 
stabilization of spinal segments in 
skeletally mature patients as an adjunct to 
fusion in the treatment of the following 
acute and chronic instabilities or 
deformities of the thoracic, lumbar, and 
sacral spine: Degenerative spondylolisthesis 
with objective evidence of neurologic 
impairment, fracture, dislocation, scoliosis, 
kyphosis, spinal tumor, and failed previous 
fusion (pseudarthrosis). FDA has determined 
that premarket approval is not necessary to 
provide such assurance. 
B. Issues Relating to Information Published 
in the 1994 Supplementary Issue of the 
Journal Spine (vol. 20S, 1994) 
    11. One comment objected that the manner 
in which the Scientific Committee 
communicated to the public the results of the 
Cohort study and related meta-analyses of the 
literature lacked scientific integrity. 
According to the comment, the articles were 
not peer reviewed, but rather they were 
accepted for publication solely by the 
Editor-in-Chief of the peer-reviewed journal 
Spine. The comment contended that publication 
of the articles without peer review prevented 
the studies from being submitted to the usual 
critical scrutiny of any peer review in the 
future. 
    While the articles describing the Cohort 
study and related meta- analysis were not 
peer-reviewed in the usual manner, they were 
subjected to a review process and published 
in an October 19, 1994, Special Supplement of 
Spine. The editorial at the beginning of the 
supplement states that, 
  The members of the Scientific Committee and 
editors of Spine felt it important that 
presentations from the (July 1994, Panel) 
meeting be available to the readers of Spine 
in an expedited manner. The articles have 
been reviewed by the Scientific Committee, 
but have not gone through the normal review 
process of the Spine Editorial Board. 
However, it has been prepared, written, 
re-written, and critiqued by all members of 
the Scientific Committee and member of the 
Spine Editorial Board, as well as presented 
in an open public forum to the scientists who 
comprised the Orthopedic and Rehabilitation 
Devices Advisory Panel to the FDA. Weaknesses 
and strengths of the studies are readily 
apparent and have been addressed by each 
author, as well as in my summation. 
    12. The comment also stated that the 
articles should not have been accepted for 
publication because the editorial policy of 
the journal requires that the recommended 
minimum followup period for studies should be 
24 months. 
    FDA disagrees. Under Spine policy, a 
sufficient length of time for followup of 
articles is necessary for publication. While 
the recommended time period for surgical 
procedures is 2 years, the policy does not 
state that studies with less than 2-year 
followup will not be published. 
C. Issues Relating to the January 1995, 
510(k) Substantial Equivalence Determination 
for a Pedicle Screw Spinal System Intended 
for Severe Spondylolisthesis 
    13. A comment stated that the 
circumstances surrounding the first 510(k) 
clearance of a pedicle screw spinal system in 
January 1995, were highly suspect because, 
until that time, FDA consistently had found 
bone screws for use in the pedicles to be not 
substantially equivalent to the identified 
predicate device, the lag screws used by Dr. 
Harrington. The comment also stated that the 
lag screws were manufactured as a custom 
device and used under a funded research grant 
and, therefore, were not in commercial 
distribution prior to 1976. 
   FDA disagrees. The 510(k) applicant 
provided new evidence 
documenting, for the first time, that: (1) A 
medical device company had manufactured and 
shipped in interstate commerce bone (lag) 
screws intended for use in the pedicles of 
the spine prior to May 28, 1976; (2) the 
devices were marketed to physicians, 
including, but not limited to, Dr. 
Harr