Sciatica Diagnosis

Sciatica might be revealed by a neuromuscular examination of the legs by a physician. There may be weakness of knee bending of foot movement, or difficulty bending the foot inward or down. Reflexes may be abnormal, with weak or absent ankle-jerk reflex.

• EMG (a recording of electrical activity in muscles)
• Nerve conduction tests

Tests are guided by the suspected cause of the dysfunction, as suggested by the history, symptoms, and pattern of symptom development. They may include various blood tests, X-rays, MRIs, or other tests and procedures.

General Information about a Sciatica Diagnosis

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.

Specific test used in a Sciatica Diagnosis

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 nerve itself.