Sciatica refers to pain that radiates along the path of the sciatic nerve, which branches from your lower back through your hips and buttocks and down each leg. Typically, sciatica affects only one side of your body.
Sciatica most commonly occurs when a herniated disk, bone spur on the spine or narrowing of the spine (spinal stenosis) compresses part of the nerve. This causes inflammation, pain and often some numbness in the affected leg.
Although the pain associated with sciatica can be severe, most cases resolve with non-operative treatments in a few weeks. People who have severe sciatica that’s associated with significant leg weakness or bowel or bladder changes might be candidates for surgery.
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 might 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 pain. Sometimes it can feel like a jolt or electric shock. It can be worse when you cough or sneeze, and prolonged sitting can aggravate symptoms. Usually only one side of your body is affected.
Some people also have numbness, tingling or muscle weakness in the affected leg or foot. You might have pain in one part of your leg and numbness in another part.
Causes
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.
Risk factors
Risk factors for sciatica include:
Age. Age-related changes in the spine, such as herniated disks and bone spurs, are the most common causes of sciatica.
Obesity. By increasing the stress on your spine, excess body weight can contribute to the spinal changes that trigger sciatica.
Occupation. A job that requires you to twist your back, carry heavy loads or drive a motor vehicle for long periods might play a role in sciatica, but there’s no conclusive evidence of this link.
Prolonged sitting. People who sit for prolonged periods or have a sedentary lifestyle are more likely to develop sciatica than active people are.
Diabetes. This condition, which affects the way your body uses blood sugar, increases your risk of nerve damage.
Complications
Although most people recover fully from sciatica, often without treatment, sciatica can potentially cause permanent nerve damage. Seek immediate medical attention if you have:
Loss of feeling in the affected leg
Weakness in the affected leg
Loss of bowel or bladder function
Diagnosis
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.
Imaging tests
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).
Treatment
If your pain doesn’t improve with self-care measures, your doctor might suggest some of the following treatments.
Medications
The types of drugs that might be prescribed for sciatica pain include:
Anti-inflammatories
Muscle relaxants
Narcotics
Tricyclic antidepressants
Anti-seizure medications
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.