Piriformis syndrome is a compression of the sciatic nerve by the piriformis muscle along the posterior aspect of the hip. Much like a carpal tunnel nerve compression at the wrist, the sciatic nerve can be compressed by the piriformis muscle. The piriformis muscle starts on the inner surface of the sacrum and attaches to the proximal femur. The muscle acts to externally rotate the femur.The sciatic nerve has several anatomic variants with respect to the piriformis muscle and may course through, around, or under the piriformis muscle belly. The suspected causes of piriformis syndrome include trauma or training which may cause a thickening or hypertrophy of the piriformis muscle belly. This in turn may cause the sciatic nerve to become compressed by the muscle belly.
Patients may complain of pain in the deep gluteal aspect of the hip. The pain may radiate down the back of the thigh or even into the foot.The pain may be described as tingling, burning, numbness or "sciatic-type" pain.
Generally, treatment for piriformis syndrome is conservative with physical therapy, activity modification, and NSAIDs. A diagnostic and possible therapeutic injection at the piriformis may be performed to help rule out other causes of sciatic nerve compression. Arthroscopic treatment for piriformis syndrome can be successfully performed in an outpatient setting using a minimally-invasive technique. The piriformis tendon is released from his insertion on the proximal femur, thereby releasing the compression on the sciatic nerve. The sciatic nerve can then be assessed along its course from proximal to distal along the posterior femur to release any further adhesions and other sites of compression.