What is Sciatica?

By Dr Liji Thomas, MD

Sciatica is the occurrence of pain in the thigh, leg and buttock, due to pinching of the sciatic nerve. This large nerve is formed from a number of smaller nerves, which leave the spinal cord between neighboring spinal vertebrae. Once they join, the sciatic nerve passes into the buttock, and then into the back of the thigh and the leg.  It may be pressed against the underlying bone at different points on its journey from the spinal cord to the leg.


The affected person usually complains of numbness, pins and needles, or pain that starts from the region of the hip and travels downward into the leg, pain or aching in the buttock, or in the ankle and foot. The pain may be excruciating, and make normal functioning impossible. It may also be mild, or anywhere in between.

This pain typically worsens when the person lifts, bends or strains, and can thus occur with sneezing, coughing or laughing heartily. It may also occur at night. Since the sciatic nerve controls both sensation and function of the leg muscles, sometimes the person experiences muscular weakness of the leg as well.

Causes of sciatica

The causes of this nerve pain may be:

  • A slipped or herniated lumbar disc.
  • Osteoarthritic changes in the lumbar spine with growth of bony spurs, thickening of the spinal vertebrae, and narrowing of the discs. All these cause narrowing of the intervertebral space or the spinal canal, both of which put pressure on the nerve roots which make up the sciatic nerve.
  • Disc degeneration because of age-related changes.
  • Spinal injury or rarely, a spinal tumor.
  • Inflamed or painful muscles in the buttock..

Diagnosis and treatment

A diagnosis of sciatica is mainly made on the basis of the clinical symptoms and signs. In most cases, slipped discs heal within about 6 weeks to 3 months. Treatment consists of reduced activity and measures to reduce pain, in the acute phase.

Total bed rest is not recommended, though you may need a couple of days off from all heavy activity. Instead, gentle exercise or physiotherapy is beneficial to firm up the lower back, preferably in the pool, which takes weight off the spine. Exercise helps relieve stiffness, keep the muscles strong and helps you take up normal activity faster.

Pain-relievers and anti-inflammatories, ice packs, and warm baths help reduce the acute pain. Other important measures include:

  • Proper posture.
  • A firm mattress for back support.
  • Avoid bending, or lifting heavy things.
  • Sit in chairs with low back support.
  • Change position, or stand up, from time to time.
  • Improving your physical state.
  • Losing weight if overweight.

X-rays or scans are not usually required, unless the pain is severe even a month after starting these measures. Of course, medical help is needed to decide when further investigation and treatment is needed.

In severe disc prolapse, epidural injections, around the nerve roots, are required to remove the pain. In some cases, disc surgery, or discectomy, is recommended. Here, a small incision is made in the back muscles so that the unhealthy disc fragments which are pressing against the nerve roots can be removed. It has a 90% short-term relief rate. Recurrence occurs in about 5%.

Complications of the nerve condition causing sciatica are rare. If there is severe pain, weakness or numbness, or loss of control over the bowel or bladder, it may indicate acute severe pressure on the spinal cord, requiring emergency treatment.


Further Reading

Last Updated: Nov 15, 2015

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