Failure of surgical decompression for a presumed case of piriformis syndrome. Case report.

Diagnosis of piriformis syndrome is difficult and its precise definition is highly controversial. In this article, the authors present the case of a patient who had clinical features suggestive of piriformis syndrome. During surgery the patient was found to have a rare variation in anatomical structures, in which the peroneal nerve was displaced by the piriformis muscle. Surgical decompression did not alleviate the patient's symptoms.