A relatively common form of back pain, sciatica refers to irritation of the sciatic nerve, which is made up of five branches of nerves that come out of your lumbar and sacral spine.

In many cases, sciatica is caused by a herniated disc that is putting pressure on the sciatic nerve. A herniated disc, which is often brought on by a sudden twisting motion or injury, is sometimes referred to as a slipped, ruptured, bulging or protruding disc, or a pinched nerve.

For others, sciatica may be caused by a narrowing of the spinal canal, or stenosis, which can be congenital or may develop over time. In this case, lesions can form and protrude into the canal and press on the nerves. Sciatic irritation may also be caused by slippage of a vertebral body in front of another, a condition known as spondylolisthesis.

Poor biomechanics, curvature of the back, weak abdominal muscles or pregnancy can contribute to this slippage, which can press on the nerve.

Symptoms of sciatica

As the longest nerve in your body, the sciatic nerve runs down from your lower back through the back of your thighs, where it divides into two branches just above your knees. It further branches out into the muscles below your knees, all the way down to your feet.

Classic symptoms of sciatica often start out with back pain, which may improve over time. However, you may begin to feel pain in one of your hamstrings or calves, and some numbness or tingling in your toes.

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. While sciatica can be very painful, permanent nerve damage is rare.

Fortunately, because the spinal cord does not extend through the lumbar (lower) spine, there is no danger of paralysis from a herniated disc in this area.

(Note: If your symptoms include progressive weakness in the legs or bladder/bowel incontinence, this may indicate a serious condition called cauda equina syndrome, which requires immediate medical attention.)

Treating sciatica

How sciatica is treated depends on the severity of the problem. You should, of course, see your doctor for an evaluation and diagnosis if the pain is keeping you from everyday activities.

Nerve pain is caused by both pressure and inflammation on the nerve, and treatment is concentrated on relieving both of these conditions.

For acute pain along the sciatic nerve, heat and/or ice packs can help relieve pain. Begin by applying heat or ice for about 20 minutes at a time, and repeating every two hours as needed. You can also alternate the two to see if this provides more relief.

For some people, taking oral steroids or an anti-inflammatory such as ibuprofen will help. If the pain is severe, your doctor may inject an epidural directly into the affected area to reduce the inflammation that is causing you pain.

Manual treatments, osteopathic or chiropractic, may help relieve the pressure. Your doctor may also suggest a physical-therapy program that includes back-strengthening or lumbar stabilization exercises.

Fortunately, most people with sciatica can expect their symptoms to improve within a matter of days. For others, relief may come within two to three months.

In a small percentage of cases, where pain is severe and the combination of manual and medical treatments have not provided relief, surgery may be necessary to help relieve both pressure and inflammation.