Sciatica is the name given to pain caused by irritation of the sciatic nerve. Anything that irritates this nerve can cause pain, ranging from mild to severe. Sciatica is usually caused by a compressed nerve in the lower spine.
Often, the term “sciatica” is confused with general back pain. However, sciatica is not just limited to the back. The sciatic nerve is the longest and widest nerve in the human body. It runs from the lower back, through the buttocks, and down the legs, ending just below the knee.
This nerve controls several muscles in the lower legs and supplies sensation to the skin of the foot and the majority of the lower leg. Sciatica is not a condition, but rather a symptom of another problem involving the sciatic nerve. Some experts estimate that up to 40 percent of people will experience sciatica at least once in their life.
Symptoms of sciatica
The main symptom is a shooting pain anywhere along the sciatic nerve; from the lower back, through the buttock, and down the back of either leg.
Other common symptoms of sciatica include:
- numbness in the leg along the nerve
- tingling sensation (pins and needles) in the feet and toes
- This pain can range in severity and may be aggravated by sitting for long periods.
Sciatica occurs when the sciatic nerve becomes pinched, usually by a herniated disk in your spine or by an overgrowth of bone (bone spur) on your vertebrae. More rarely, the nerve can be compressed by a tumor or damaged by a disease such as diabetes.
During the physical exam, your doctor may check your muscle strength and reflexes. For example, you may be asked to walk on your toes or heels, rise from a squatting position and, while lying on your back, lift your legs one at a time. Pain that results from sciatica will usually worsen during these activities.
Many people have herniated disks or bone spurs that will show up on X-rays and other imaging tests but have no symptoms. So doctors don’t typically order these tests unless your pain is severe, or it doesn’t improve within a few weeks.
- X-ray. An X-ray of your spine may reveal an overgrowth of bone (bone spur) that may be pressing on a nerve.
- MRI. This procedure uses a powerful magnet and radio waves to produce cross-sectional images of your back. An MRI produces detailed images of bone and soft tissues such as herniated disks. During the test, you lie on a table that moves into the MRI machine.
- CT scan. When a CT is used to image the spine, you may have a contrast dye injected into your spinal canal before the X-rays are taken — a procedure called a CT myelogram. The dye then circulates around your spinal cord and spinal nerves, which appear white on the scan.
- Electromyography (EMG). This test measures the electrical impulses produced by the nerves and the responses of your muscles. This test can confirm nerve compression caused by herniated disks or narrowing of your spinal canal (spinal stenosis).
If your pain doesn’t improve with self-care measures, your doctor might suggest some of the following treatments.
The types of drugs that might be prescribed for sciatica pain include:
- Muscle relaxants
- Tricyclic antidepressants
- Anti-seizure medications
- Physical therapy
Once your acute pain improves, your doctor or a physical therapist can design a rehabilitation program to help you prevent future injuries. This typically includes exercises to correct your posture, strengthen the muscles supporting your back and improve your flexibility.
In some cases, your doctor might recommend injection of a corticosteroid medication into the area around the involved nerve root. Corticosteroids help reduce pain by suppressing inflammation around the irritated nerve. The effects usually wear off in a few months. The number of steroid injections you can receive is limited because the risk of serious side effects increases when the injections occur too frequently.
This option is usually reserved for when the compressed nerve causes significant weakness, loss of bowel or bladder control, or when you have pain that progressively worsens or doesn’t improve with other therapies. Surgeons can remove the bone spur or the portion of the herniated disk that’s pressing on the pinched nerve.