Sciatica

Sciatica is the result of either inflammation or irritation of the sciatic nerve. The sciatic nerve is a nerve which starts at the spinal cord in the low back, extends through the piriformis muscle in the buttock, and branches down the back of the leg, and into the foot. Causes of sciatica are disc herniations or other degenerative changes in the lower part of the spine, piriformis syndrome, and, rarely, tumors along the spine. Stress can also play a role, particularly in exacerbations of sciatica.

The cause of sciatica is often difficult to identify in actual practice. The use of MRI’s to identify the cause is common, but problematic in many cases. While tumors are typically readily seen on an MRI, it is often difficult to identify degenerative changes of the spine that might cause sciatica. Some patients will have MRI’s that show, for example, a disc herniation and nerve root irritation that is consistent with their symptoms. Many patients, however, have sciatica without any objective findings on MRI. Still others commonly have findings on MRI that are inconsistent with their symptoms. For these reasons, providers often pursue epidural steroid injections and nerve blocks in an attempt to identify the cause of sciatica. However, these procedures can also provide unreliable results. As such, with the exception of tumor-related sciatica, healthcare providers typically presume the cause of the condition without ever obtaining definite confirmation.

Is there a cure for sciatica?

The vast majority of acute cases of sciatica resolve on their own within a few weeks to months.

However, sometimes it continues and becomes chronic. It’s considered chronic when lasting longer than six months. Typically, chronic sciatica has no cure and lasts indefinitely.

Chronic sciatica is likely to involve a secondary complication called central sensitization.¹ Central sensitization isa highly reactive state of the nervous system, which amplifies pain. It can also sometimes cause sensitivity to touch, fatigue, poor sleep, anxiety, and depression.

Therapies & Procedures for sciatica

In the healthcare community, there is no conventional agreement as to what the best treatment is for sciatica. Treatment recommendations are often dependent on the type of provider that the patient sees. In part, it is due to the above-noted difficulties with confirming a cause of sciatica. In the absence of a definite confirmation, healthcare providers must base treatment recommendations on their presumptions of what is causing it. As such, the area of the healthcare provider’s expertise can sometimes influence these presumptions. Surgeons and interventional pain physicians can tend to presume a cause of degenerative changes of the spine. As such, patients who see these types of providers will tend to get recommendations for surgery or interventional procedures. Physical therapists can tend to presume either degenerative changes of the spine or piriformis syndrome. Patients who see physical therapists will tend to get recommendations for stretching and strengthening exercises. Health psychologists and other chronic pain rehabilitation providers focus on the nervous system, of which the sciatic nerve is a part. Patients who see such providers tend to get recommendations for ways to reduce the reactivity of the sciatic nerve, as well as the whole nervous system, if central sensitization is occurring.

Common therapies for sciatica are the following:

• Surgeries: laminectomies, discectomies, and fusions
• Interventional procedures: epidural steroid injections, nerve blocks, rhizotomies, and spinal cord stimulator implants
• Physical therapies: stretching and strengthening exercises
• Chronic pain rehabilitation programs

Surgeries

Despite how frequently surgical and interventional procedures are performed in the healthcare system, most of these procedures have limited benefit. Surgery for sciatica in the first few months after onset has been shown to provide more rapid relief than conservative approaches. However, by one-year follow-up, conservative approaches will catch up, so to speak, and the amount of pain relief will be the same.² The long-term effectiveness of surgery for sciatica remains unclear as no studies to date have been published on its long-term effectiveness. Conventional wisdom is that pain reduction with surgery is typically not permanent. As a result, despite taking a little longer, most healthcare providers prefer to trial conservative approaches before surgery.

Interventional pain procedures

Research on the outcomes of epidural steroid injections, nerve blocks and rhizotomies show that they are all ineffective on average.^{3, 4, 5} 

There is limited evidence to support the use of spinal cord stimulator implants. A number of poor quality studies show mildly positive results. The use of spinal cord stimulators seems somewhat more helpful with leg pain that results from failed back surgeries than true sciatica.^{6, 7} 

Physical therapy

Physical therapy for acute sciatica is mildly to moderately effective.⁸ The quality of the effectiveness studies is moderate to good.

Chronic pain rehabilitation programs

For chronic sciatica, chronic pain rehabilitation programs are typically the most beneficial treatment. Effectiveness is measured by multiple criteria, including pain reduction, rates of returning to work, and reducing the need for further healthcare services.^{9, 10} The quality of studies is moderate.

References

1. O'Neill, S., Manniche, C., Graven-Nielsen, T., Arendt-Nielsen, L. (2007). Generalized deep-tissue hyperalgesia in patients with low-back pain. European Journal of Pain, 11, 415-420.

2. Peul, W. C., et al. (2007). Surgery versus prolonged conservative treatment for sciatica. New England Journal of Medicine, 356, 2245-2256.

3. van Tulder, M. W., Koes, B., Seitsalo, S., & Malmivaara, A. (2006). Outcomes of invasive treatment strategies in low back pain and sciatica: An evidence based review. European Spine Journal, 15, S82-S89.

4. Arden, N. K., Price, C., Reading, I., Stubbing, J., Hazelgrove, J., Dunne, C., Michel, M., Rogers, P., & Cooper C. (2005). A multicentre randomized controlled trial of epidural corticosteroid injections for sciatica: The WEST study. Rheumatology, 44, 1399-1406.

5. Ng, L., Chaudhary, N., & Sell, P. (2005). The efficacy of corticosteroids in periradicular infiltration in chronic radicular pain: A randomized, double-blind, controlled trial. Spine, 30, 857-862.

6. Chou, R., Atlas, S. J., Stanos, S. P., & Rosenquist, R. W. (2009). Nonsurgical interventional therapies for low back pain: A review of the evidence for the American Pain Society clinical practice guideline. Spine, 34, 1078-1093.

7. Taylor, R. S., Van Buyten, J., & Buchser, E. (2005). Spinal cord stimulation for chronic back and leg pain and failed back surgery syndrome: A systematic review and analysis of prognostic factors. Spine, 30, 152-160.

8. Hayden, J. A., van Tulder, M. W., Malmivaara, A. V., & Koes, B. W. (2005). Meta-analysis: Exercise therapy for non-specific low back pain. Annals of Internal Medicine, 142, 765-775.

9. Gatchel, R., J., & Okifuji, A. (2006). Evidence-based scientific data documenting the treatment and cost-effectiveness of comprehensive pain programs for chronic non-malignant pain. Journal of Pain, 7, 779-793.

10. Turk, D. C. (2002). Clinical effectiveness and cost-effectiveness of treatments for patients with chronic pain. Clinical Journal of Pain, 18, 355-365.

Date of publication: April 27, 2012

Date of last modification: October 8, 2018