Sciatica caused by piriformis muscle syndrome: report of two cases.

The diagnosis of piriformis muscle syndrome, an unusual cause of sciatica, is difficult. However, with the advancement of imaging techniques, it has become clear that the condition is not just clinical speculation, but is a definite entity. We report on two cases with piriformis muscle syndrome, diagnosed on the basis of: a history of sciatica; physical findings, such as a tender point at the sciatic notch and around the piriformis muscle by palpation of the gluteal region, and by a digital pelvic examination; and computed tomography (CT) to demonstrate hypertrophy of the piriformis muscle. In both cases, a tenotomy of the piriformis muscle at the greater trochanter relieved entrapment of the sciatic nerve and gave satisfactory results. Since local tenderness at the piriformis muscle is the most reliable physical finding, a pelvic examination is recommended in the evaluation of suspected cases of piriformis muscle syndrome. CT is helpful in showing hypertrophy of the piriformis muscle. Detailed history taking, a careful physical examination, and versatile use of CT or magnetic resonance imaging can lead to an early, accurate diagnosis and proper treatment.