Human Diseases and Conditions

What is sciatica?

Sciatica is pain resulting from irritation of the sciatic nerve. The pain of sciatica is typically felt from the low back to behind the thigh and radiating down below the knee. The sciatic nerve is the largest nerve in the body and begins from nerve roots in the lumbar spinal cord in the low back and extends through the buttock area to send nerve endings down the lower limb.

Sign & Symptoms


Pain that radiates from your lower (lumbar) spine to your buttock and down the back of your leg is the hallmark of sciatica. You may feel the discomfort almost anywhere along the nerve pathway, but it's especially likely to follow a path from your low back to your buttock and the back of your thigh and calf.
The pain can vary widely, from a mild ache to a sharp, burning sensation or excruciating discomfort. Sometimes it may feel like a jolt or electric shock. It may be worse when you cough or sneeze, and prolonged sitting can aggravate symptoms. Usually only one lower extremity is affected.
Sciatica symptoms include:

• Pain. It's especially likely to occur along a path from your low back to your buttock and the back of your thigh and calf.
• Numbness or muscle weakness along the nerve pathway in your leg or foot. In some cases, you may have pain in one part of your leg and numbness in another.
• Tingling or a pins-and-needles feeling, often in your toes or part of your foot.
• A loss of bladder or bowel control. This is a sign of cauda equina syndrome, a rare but serious condition that requires emergency care. If you experience either of these symptoms, seek medical help immediately.

When to see a doctorMild sciatica usually goes away given time and patience. Call your doctor if self-care measures fail to ease your symptoms or if your pain lasts longer than a week, is severe or becomes progressively worse. Get immediate medical care if:

• You experience sudden, severe pain in your low back or leg and numbness or muscle weakness in your leg
• The pain follows a violent injury, such as a traffic accident
• You have trouble controlling your bowels or bladder

Causes:

Your sciatic nerve branches from your spinal cord through your hips and buttocks and down the back of each leg. This nerve controls many of the muscles in your lower legs and provides feeling to your thighs, legs and feet. Sciatica may develop when a nerve root is compressed in your lower (lumbar) spine — often as a result of a herniated disk in your lower back.
Disks are pads of cartilage that separate the bones (vertebrae) in your spine. Filled with a gel-like substance, they keep your spine flexible and act as shock absorbers to cushion the vertebrae when you move.
If the outer covering of a disk tears (herniates), gel may seep out and press on a nerve root, causing pain in your back, leg or both. If the damaged disk is in the lower part of your back, you may also experience numbness, tingling or weakness in your buttock, leg or foot.
Although a herniated disk is a common cause of sciatic nerve pain, other conditions also can put pressure on your sciatic nerve, including:

• Lumbar spinal stenosis. Spinal stenosis is a narrowing of one or more areas in your spine — most often in your upper or lower back. When the narrowing occurs in the lower spine, the lumbar and sacral nerve roots may be affected.
• Spondylolisthesis. This condition, often the result of degenerative disk disease, occurs when one vertebra slips slightly forward over another vertebra. The displaced bone may pinch the sciatic nerve where it leaves your spine.
• Piriformis syndrome. The piriformis muscle starts at your lower spine and connects to each thighbone (femur). Piriformis syndrome occurs when the muscle becomes tight or goes into spasms, putting pressure on the sciatic nerve. Prolonged sitting, car accidents and falls can contribute to piriformis syndrome.
• Spinal tumors. In the spine, tumors can occur inside the spinal cord, within the membranes (meninges) that cover the spinal cord, or in the space between the spinal cord and the vertebrae. As it grows, a tumor compresses the cord itself or the nerve roots.
• Trauma. A car accident, fall or blow to your spine can injure the lumbar or sacral nerve roots.
• Sciatic nerve tumor or injury. Sometimes, the sciatic nerve itself may be affected by a tumor or injury.
• Other causes. In some cases, your doctor may not be able to find a cause for your sciatica. A number of problems can affect your bones, joints and muscles, all of which could potentially result in sciatic pain.

How is sciatica diagnosed?

Sciatica is diagnosed with a physical exam and medical history. The typical symptoms and certain examination maneuvers help the health-care practitioner to diagnose sciatica. Sometimes, X-rays, films, and other tests, such as CT scan, MRI scan, and electromyogram, are used to further define the exact causes of sciatica


Treatment & Pharmacology

For most people, sciatica responds well to self-care measures. These may include use of alternating cold packs and hot packs, stretching, exercise, and use of over-the-counter (OTC) medications. Beyond the self-care measures you may have taken, your doctor may recommend the following:

• Physical therapy. If you have a herniated disk, physical therapy can play a vital role in your recovery. Once acute pain improves, your doctor or a physical therapist can design a rehabilitation program to help prevent recurrent injuries.
  Rehabilitation typically includes exercises to help correct your posture, strengthen the muscles supporting your back and improve your flexibility. Your doctor will have you start physical therapy, exercise or both as early as possible. It's the cornerstone of your treatment program and should become part of your permanent routine at home.
• Prescription drugs. In some cases, your doctor may prescribe an anti-inflammatory medication along with a muscle relaxant. Narcotics also may be prescribed for short-term pain relief. Tricyclic antidepressants and anticonvulsant drugs also can help ease chronic pain. They may help by blocking pain messages to the brain or by enhancing the production of endorphins, your body's natural painkillers.

More aggressive treatmentsWhen conservative measures don't alleviate your pain within a few months, one of the following may be an option for sciatica treatment:

• Epidural steroid injections. In some cases, your doctor may recommend injection of a corticosteroid medication into the affected area. Corticosteroids suppress inflammation around the irritated nerve, thereby helping to relieve pain.
  Their usefulness in treating sciatica remains a matter of debate. Some research has found that corticosteroids can provide short-term symptom relief but that these medications aren't a long-term solution. In addition, corticosteroids can have side effects, so the number of injections you can receive is limited. If your doctor recommends corticosteroids, he or she will determine a safe course of injections for you.
• Surgery. This is usually reserved for times when the compressed nerve causes significant weakness, bowel or bladder incontinence or when you have pain that gets progressively worse or doesn't improve with other therapies.
  Surgical options include diskectomy and microdiskectomy. In diskectomy, surgeons remove a portion of a herniated disk that's pressing on a nerve. Ideally, most of the disk is left intact to preserve as much of the normal anatomy as possible. Sometimes a surgeon will perform this operation through a small incision while looking through a microscope (microdiskectomy).
  Success rates of standard diskectomy and microdiskectomy are about equal, but you may have less pain and recover more quickly with microdiskectomy. Discuss which option might be best for you with your doctor, and carefully weigh the potential benefits of surgery against the risks.

Prevention:


It's not always possible to prevent sciatica, and the condition may recur. The following suggestions can play a key role in protecting your back:

• Exercise regularly. This is the most important thing you can do for your overall health as well as for your back. Pay special attention to your core muscles — the muscles in your abdomen and lower back that are essential for proper posture and alignment. Ask your doctor to recommend specific activities.
• Maintain proper posture when you sit. Choose a seat with good lower back support, arm rests and a swivel base. Consider placing a pillow or rolled towel in the small of your back to maintain its normal curve. Keep your knees and hips level.
  When working at a computer, adjust your chair so that your feet are flat on the floor and your arms rest on your desk or the chair's arms, with your elbows bent at a right angle. Take frequent breaks, even if it's just to walk around your office.
• Use good body mechanics. Being conscious of how you stand, how you lift heavy objects and even how you sleep can go a long way toward keeping your back healthy. That's because poor posture stresses your back, leading to fatigue and stress on joints and nerves.
  If you stand for long periods, rest one foot on a stool or small box from time to time. While you stand, hold reading material at eye level instead of bending forward.
  When you lift something heavy, let your lower extremities do the work. Move straight up and down. Keep your back straight and bend only at the knees. Hold the load close to your body. Avoid lifting and twisting simultaneously. Find a lifting partner if the object is heavy or awkward or if you're fatigued.