Myositis Ossificans of the Piriformis Muscle: First Reported Case of Non-Traumatic Sciatic Nerve Injury Requiring Surgical Decompression.

There are only scarce reports of other presentations of non-traumatic myositis ossificans (MO). We describe the first reported case of non-traumatic MO of the piriformis muscle causing irretractability neuropathic pain in the sciatic nerve territory and signs of severe motor and sensory deficit, requiring surgical decompression. The patient presented a complete resolution of pain and partial resolution of neurological deficits. The surgical images and protocol, imaging tests, and post-surgical follow-up were reviewed, using validated scales and rating systems. We concluded that MO is an infrequent condition, but high suspicion is required because early treatment reduces the development of permanent neurological deficits.