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What you need to know about Sciatica

About Dr Tehseen Riaz

Overview
Sciatica—pain along the large sciatic nerve that runs from the lower back down through the buttocks and along the back of each leg – is a relatively common form of back pain.

Sciatica is usually caused by pressure on the sciatic nerve from a herniated disc (also referred to as a bulging disc, ruptured disc or pinched nerve). The problem is often diagnosed as a "radiculopathy", meaning that a disc has protruded from its normal position in the vertebral column and is putting pressure on the radicular nerve (nerve root).

For some people, the pain from sciatica can be severe and debilitating. For others, the pain might be infrequent and irritating, but has the potential to get worse. Usually, sciatica only affects one side, and the pain often radiates through the buttock and/or leg.

One or more of the following sensations may occur:
Pain in the buttocks and/or leg that is worse when sitting
Burning or tingling down the leg
Weakness, numbness or difficulty moving the leg or foot
A constant pain on one side of the buttocks
A shooting pain that makes it difficult to stand up
While sciatica can be very painful, it is rare that permanent nerve damage (tissue damage) will result. Most pain syndromes result from inflammation and will get better within two weeks to a few months. Also, because the spinal cord is not present in the lower (lumbar) spine, a herniated disc in this area of the anatomy does not present a danger of paralysis.

Symptoms that may constitute a medical emergency include progressive weakness in the legs or bladder/bowel incontinence. Patients with these symptoms may have cauda equina syndrome and should seek immediate medical attention.

Any condition that causes irritation or impingement on the sciatic nerve can cause the pain associated with sciatica. The most common cause is lumbar herniated disc. Other common causes include lumbar spinal stenosis, degenerative disc disease, or isthmic spondylolisthesis.

Nerve pain is caused by a combination of pressure and inflammation on the nerve root, and treatment is centered on relieving both of these conditions. 

Treatments include:
Manual treatments (including physical therapy and osteopathic or chiropractic treatments) to help relieve the pressure.
Medical treatments (such as NSAID’s, oral steroids, or epidural steroid injections) to help relieve the inflammation.
Surgery (such as microdiscectomy or lumbar laminectomy) to help relieve both the pressure and inflammation may be warranted if the pain is severe and has not been relieved with appropriate manual or medical treatments.

What causes sciatica?
The sciatic nerve is the largest nerve in the body. It starts in the low back at lumbar segment 3 (L3). The nerve roots run through the bony canal, and at each level a pair of nerve roots exits from the spine.

The nerve is named for the upper vertebral body that it runs between (for example, the nerve that exits at L4-L5 is named L4). 
The nerve passing to the next level runs over a weak spot in the disc space, which is the reason discs tend to herniate (extrude) right under the nerve root and can cause leg pain.

The symptoms (pain, numbness, tingling, weakness) are different depending on where the pressure on the nerve occurs. For example, a lumbar segment 5 (L5) nerve impingement can cause weakness in extension of the big toe and potentially in the ankle (foot drop).

Common conditions that can result in pain along the sciatic nerve include:
Lumbar herniated disc—A herniated disc occurs when the soft inner core of the disc (nucleus pulposus) extrudes through the fibrous outer core (annulus) and the bulge places pressure on the contiguous nerve root. In general, it is thought that a sudden twisting motion or injury can lead to an eventual disc herniation. A herniated disc is sometimes referred to as a slipped, ruptured, bulging, protruding disc, or a pinched nerve.

Lumbar spinal stenosis—This condition involves a narrowing of the spinal canal. It is more common in adults over age 60, and typically results from enlarged facet joints placing pressure on the nerve roots as they exit the spine.

Degenerative disc disease—While disc degeneration is a natural process that occurs with aging, in some cases it can also lead to pain along the sciatic nerve. The condition is diagnosed when a weakened disc results in excessive micro-motion at the corresponding vertebral level and inflammatory proteins from inside the disc can become exposed and irritate the area.

Isthmic spondylolisthesis—Relatively common in adults (approximately 5% to 7% of adults), this condition rarely causes pain. 
It occurs when a small stress fracture, often at the fifth segment, allows the L5 vertebral body to slip forward on the S1 vertebral body. Caused by a combination of disc space collapse, the fracture, and the vertebral body slipping forward, the L5 nerve can get pinched as it exits the spine.

Piriformis syndrome—The sciatic nerve can get irritated as it runs under the piriformis muscle in the buttocks.

Sacroiliac joint dysfunction—Irritation of the sacroiliac joint can also irritate the L5 nerve, which lies on top of it, and cause sciatica.

How is sciatica treated?
The good news is that if pain along the sciatic nerve is going to get better on its own it will usually do so within a couple of days or weeks. In fact, the vast majority of this type of back and/or leg pain usually heals on its own within six to twelve weeks.

Conservative care:
During an episode of sciatic pain there are a number of conservative care options available to help alleviate the pain and discomfort.

Heat/ice
For acute pain along the sciatic nerve, heat and/or ice packs are most readily available and can help alleviate the pain, especially in the acute phase. Usually ice or heat is applied for approximately 20 minutes, and repeated every two hours. Most people use ice first, but some people find more relief with heat. The two may be alternated.

Medications
Over-the-counter or prescription medications may also be helpful. Non-steroidal anti-inflammatory drugs (NSAIDs) or oral steroids can be helpful in reducing the inflammation and pain.

Epidural steroid injections
If the pain is severe, an epidural injection can be performed to reduce the inflammation. An epidural is different from oral medications because it injects steroids directly to the painful area to help decrease the inflammation that may be causing the pain. While the effects tend to be temporary (providing pain relief for as little as one week up to a year), an epidural can be very effective in providing relief from an acute episode of pain. Importantly, it can provide sufficient relief to allow a patient to progress with a conditioning program.

Conservative care specialists
A visit to a physical therapist, osteopathic physician, chiropractor or physiatrist can be helpful both to alleviate the painful symptoms and to help prevent future recurrences of sciatica. These conservative care professionals can assist in providing pain relief and developing a program to condition the back.

Surgical treatments:
If the pain is severe and has not gotten better within six to twelve weeks, it is reasonable to consider spine surgery. Depending on the cause and the duration of the pain, one of two surgical procedures may be considered: a microdecompression 
(microdiscectomy) or an open decompression (lumbar laminectomy).

Microdiscectomy (microdecompression)
In cases where the pain is due to a disc herniation, a microdiscectomy may be considered after 4 to 6 weeks if the pain is not relieved by conservative means. Urgent surgery is only necessary if there is progressive weakness in the legs, or sudden loss of bowel of bladder control. A microdiscectomy is typically an elective procedure, and the decision to have surgery is based on 
the amount of pain and dysfunction the patient is experiencing, and the length of time that the pain persists. Approximately 90% to 95% of patients will experience relief from their pain after this type of surgery.

Lumbar laminectomy (open decompression)
Lumbar spinal stenosis often causes pain that waxes and wanes over many years. Surgery may be offered as an option if the patient’s activity tolerance falls to an unacceptable level. Again, surgery is elective and need only be considered for those patients who have not gotten better after conservative treatments. After an lumbar laminectomy (open decompression), approximately 70% to 80% of patients experience pain relief from their pain.

Courtesy : Stephen H. Hochschuler, MD
March 30, 2000
Updated October 9, 2001