Pressure on a nerve in any part of your body can cause weakness, numbness and pain. A pinched nerve is a symptom, not a cause. Swelling of tendons in your wrist can compress nerves, leading to carpal tunnel syndrome. A herniated disc in your lower back can pinch a sciatic nerve root, causing sciatica--pain in your buttock and down your leg. Pain from a pinched nerve can range from mild to disabling.
Your sciatic nerve runs down your spine, through your buttocks and down the back of each leg. Anything that pinches the the sciatic nerve in your lower back (lumbar region) can cause sciatica, also known as radiculopathy.
The most common cause by far is a ruptured or herniated disc--the tough, flexible pads that provide flexibility and cushioning between each vertebrae in your spine. When the swollen disc compresses the nerve root, the pain can be felt from your lower back to your foot.
Other less common causes of sciatica include spondylolisthesis piriformis syndrome, lumbar spinal stenosis, tumours and trauma.
Sciatica symptoms depend on what part of your spine is swelling. The most commonly pinched nerves are at the L5 (lumbar 5) and S1 (sacral 1) vertebrae, which will cause pain and numbness through the buttocks, down the back of the calf and into the foot. Pinched nerves at the L4 and L3 level can run down the back, side or front of the thigh but rarely involve the foot.
Usually only one leg is affected, and although the pain originates in the lower back, you may not have back pain. In some cases your leg can become numb and very weak, as blood supply is cut off to the nerve.
Most cases of sciatica resolve within four to eight weeks, according to the Mayo Clinic, and mild cases may require no medical intervention. If the pain becomes intolerable, lasts for more than a month, or you lose control of your bladder or bowels, seek immediate medical attention.
Diagnosis will typically include a basic exam. Your doctor can ask you to perform certain exercises like lying on your back and lifting your leg, touching your toes and rising from a crouched position. She may also perform reflex tests in order to pinpoint which nerves are affected.
X-rays cannot diagnose a herniated disc, but they can identify tumours and bone spurs. A computerised tomography (CT) scan will show impinged nerves. The most complete test is an MRI (magnetic resonance imaging), which provides clear images of your spine, soft tissues and nerves.
Treatment depends on the severity of the symptoms. Your doctor may prescribe anti-inflammatory drugs and muscle relaxants. For severe pain she may suggest a short course of narcotic painkillers. Tricyclic antidepressants and anticonvulsant medications are also indicated for chronic nerve pain and to help you sleep.
A short, high-dose course of steroids, or a steroid injection, can help reduce swelling around the spine if other medications are ineffective.
Physical therapy and back exercises, and retraining you in how to walk, stand and sit are an important part of recovery from sciatica.
In severe or chronic cases, surgery to remove the part of the disk that is compressing the spine is indicated.
Regular exercise, particularly low-impact movement like swimming or walking, will keep your back muscles and spine flexible. Either on your own or with a physical therapist, come up with a daily exercise regimen to strengthen your core muscles and stay limber. Pay attention to posture when sitting, standing and lifting.