Sciatica is a condition involving impaired movement and/or
sensation in the leg, caused by damage to the sciatic nerve.
Information about Sciatica
Sciatica is a form of peripheral neuropathy. It occurs when there is damage to the
sciatic nerve, located in the back of the leg. This nerve controls the muscles of the back
of the knee and lower leg and provides sensation to the back of the thigh, part of the
lower leg and the sole of the foot. Incomplete damage to the sciatic nerve may appear
identical to damage to one of the branches of the sciatic nerve (tibial nerve dysfunction
or common peroneal nerve dysfunction).
A problem in a single nerve group, such as the sciatic nerve, is classified as a mononeuropathy.
The usual causes are direct trauma (often due to an injection into the
buttocks), prolonged external pressure on the nerve, and pressure on the
nerve from nearby body structures. It can also be caused by entrapment --
pressure on the nerve where it passes through a narrow structure. The damage
slows or prevents conduction of impulses through the nerve.
The sciatic nerve is commonly injured by fractures of the pelvis, gunshot wounds, or other
trauma to the buttocks or thigh. Prolonged sitting or lying with pressure on the buttocks
may also injure it. Systemic diseases, such as diabetes, can typically damage many
different nerves, including the sciatic nerve. The sciatic nerve may also be harmed by
pressure from masses such as a tumor or abscess, or by bleeding in the pelvis.
In many cases, no cause can be identified.
Note: A ruptured lumbar disk in the spine may cause symptoms that simulate the symptoms of
sciatic nerve dysfunction.
Symptoms of Sciatica
- Sensation changes
- Of the back of the calf or the sole of the foot
- Numbness, decreased sensation
- Tingling, burning sensation
- Pain, may be severe
- Abnormal sensations
- Weakness of the knee or foot
- Difficulty walking
- Inability to move the foot (in severe cases)
- Inability to bend the knee (in severe cases)
Individuals with sciatica may experience some lower back pain, but the most common
symptom is pain that radiates through one buttock and down the back of that leg. The most
identified cause of the pain is compression or pressure on the sciatic nerve. The extent
of the pain varies between individuals. Some people describe pain that centers in the area
of the hip, and others perceive discomfort all the way to the foot. The quality of the
pain also varies; it may be described as tingling, burning, prickly, aching, or stabbing.
Onset of sciatica can be sudden, but it can also develop gradually. The pain may be
intermittent or continuous, and certain activities, such as bending, coughing, sneezing,
or sitting, may make the pain worse.
Chronic pain may arise from more than just compression on the nerve. According to some
pain researchers, physical damage to a nerve is only half of the equation. A developing
theory proposes that some nerve injuries result in a release of neurotransmitters and
immune system chemicals that enhance and sustain a pain message. Even after the injury has
healed, or the damage has been repaired, the pain continues. Control of this abnormal type
of pain is difficult.
Diagnosis of Sciatica
Before treating sciatic pain, as much information as possible is collected. The
individual is asked to recount the location and nature of the pain, how long it has
continued, and any accidents or unusual activities prior to its onset. This information
provides clues that may point to back strain or injury to a specific location. Back pain
from disk disease, piriformis syndrome, and back strain must be differentiated from more
serious conditions such as cancer or infection. Lumbar stenosis, an overgrowth of the
covering layers of the vertebrae that narrows the spinal canal, must also be considered.
The possibility that a difference in leg lengths is causing the pain should be evaluated;
the problem can be easily be treated with a foot orthotic or built-up shoe.
Often, a straight-leg-raising test is done, in which the person lies face upward and
the health- care provider raises the affected leg to various heights. This test pinpoints
the location of the pain and may reveal whether it is caused by a disk problem. Other
tests, such as having the individual rotate the hip joint, assess the hip muscles. Any
pain caused by these movements may provide information about involvement of the piriformis
muscle, and piriformis weakness is tested with additional leg-strength maneuvers.
Further tests may be done depending on the results of the physical examination and
initial pain treatment. Such tests might include magnetic resonance imaging (MRI) and
computed tomography scans (CT scans). Other tests examine the conduction of electricity
through nerve tissues, and include studies of the electrical activity generated as muscles
contract (electromyography), nerve
conduction velocity, and evoked potential testing. A more invasive test involves injecting
a contrast substance into the space between the vertebrae and making x-ray images of the
spinal cord (myelography), but this procedure is usually done only if surgery is being
considered. All of these tests can reveal problems with the vertebrae, the disk, or the
Treatment of Sciatica
Initial treatment for sciatica focuses on pain relief. For acute or very painful
flare-ups, bed rest is advised for up to a week in conjunction with medication for the
pain. Pain medication includes acetaminophen, nonsteroidal anti-inflammatory drugs
(NSAIDs), such as aspirin, or muscle relaxants. If the pain is unremitting, opioids may be
prescribed for short-term use or a local anesthetic will be injected directly into the
lower back. Massage and heat application may be suggested as adjuncts.
If the pain is chronic, different pain relief medications are used to avoid long-term
dosing of NSAIDs, muscle relaxants, and opioids. Antidepressant drugs, which have been
shown to be effective in treating pain, may be prescribed alongside short-term use of
muscle relaxants or NSAIDs. Local anesthetic injections or epidural steroids are used in
As the pain allows, physical therapy is introduced into the treatment regime.
Stretching exercises that focus on the lower back, buttock, and hamstring muscles are
suggested. The exercises also include finding comfortable, pain-reducing positions.
Corsets and braces may be useful in some cases, but evidence for their general
effectiveness is lacking. However, they may be helpful to prevent exacerbations related to
With less pain and the success of early therapy, the individual is encouraged to follow
a long-term program to maintain a healthy back and prevent re-injury. A physical therapist
may suggest exercises and regular activity, such as water exercise or walking. Patients
are instructed in proper body mechanics to minimize symptoms during light lifting or other
If the pain is chronic and conservative treatment fails, surgery to repair a herniated
disk or cut out part or all of the piriformis muscle may be suggested, particularly if
there is neurologic evidence of nerve or nerve-root damage.
Alternative treatment of Sciatica
Massage is a recommended form of therapy, especially if the sciatic pain arises from
muscle spasm. Symptoms may also be relieved by icing the painful area as soon as the pain
occurs. Ice should be left on the area for 30-60 minutes several times a day. After 2-3
days, a hot water bottle or heating pad can replace the ice. Chiropractic or osteopathy
may offer possible solutions for relieving pressure on the sciatic nerve and the
accompanying pain. Acupuncture and biofeedback may also be useful as pain control methods.
Body work, such as the Alexander technique, can assist an individual in improving posture
and preventing further episodes of sciatic pain.
Prognosis of Sciatica
Most cases of sciatica are treatable with pain medication and physical therapy. After
4-6 weeks of treatment, an individual should be able to resume normal activities.
Prevention of Sciatica
Some sources of sciatica are not preventable, such as disk degeneration, back strain
due to pregnancy, or accidental falls. Other sources of back strain, such as poor posture,
overexertion, being overweight, or wearing high heels, can be corrected or avoided.
Cigarette smoking may also predispose people to pain, and should be discontinued.
General suggestions for avoiding sciatica, or preventing a repeat episode, include
sleeping on a firm mattress, using chairs with firm back support, and sitting with both
feet flat on the floor. Habitually crossing the legs while sitting can place excess
pressure on the sciatic nerve. Sitting a lot can also place pressure on the sciatic
nerves, so it's a good idea to take short breaks and move around during the work day, long
trips, or any other situation that requires sitting for an extended length of time. If
lifting is required, the back should be kept straight and the legs should provide the
lift. Regular exercise, such as swimming and walking, can strengthen back muscles and
improve posture. Exercise can also help maintain a healthy weight and lessen the
likelihood of back strain.