Piriformis syndrome: Pathogenesis, diagnosis, and treatment

Abstract

The failure of conservative treatment for lumbosacral disk disorders often leads to surgery. If the pain is produced by sciatic neuritis rather than sciatic radiculitis, operative treatment may be unavailing. This paper describes the mechanism by which piriformis syndrome causes sciatic neuritis and differentiates neuritis from radiculitis, the treatment of which often results in the 'failed disk syndrome'. Sciatic neuritis is now believed to result from irritation of the sciatic nerve sheath, which is caused by biochemical agents released from an inflamed piriformis muscle where the two structures meet at the greater sciatic foramen. The symptoms of piriformis syndrome present almost identically to lumbar disk syndrome, except for the consistent absence of true neurologic findings. Diagnosis is accomplished by palpation of myofascial trigger points within the piriformis muscle. Computed tomography, myelography, roentgenography, and electromyography are of limited diagnostic value. Treatment, which consists of a conservative approach employing local anesthetics and osteopathic manipulation, is without significant risk. Reducing muscle spasm, restoring joint motion, and keeping the patient ambulatory and in motion are keys to successful treatment.