[Sciatic xeuropathy secondary to compression by a heterotopic ossification due to myositis ossificans traumatica. (Case report and review of the literature)].

We describe a case of sciatic nerve entrapment neuropathy due to a posttraumatic heterotopic ossification (myositis ossificans traumatica). A 52 y.o. man was examined complaining from right lower limb pain and weakness progressing for one year after a blunt trauma and a hematoma of the hip. Clinical examination demonstrated sciatic nerve palsy with pain and paresthesia felt distal to the lesion. Electrodiagnostic studies show severe denervation changes in the tibialis anterior, extensor digitorum brevis and gastrocnemius muscles. Both radiography and CT scan revealed new bone formation in the soft tissue in the upper third of the hip. Surgical exploration discovered an osseous tunnel in the fascial plane between the semitendinous and biceps femoris muscles, encasing the sciatic nerve in a length of 12 cm. The lesion was hard and intimately associated with the epineuria. Histopathological examination of the lesion demonstrated mature, lamellar bone structure. Under optical magnification the ectopic bone was totally removed and decompression of the sciatic nerve was achieved. Nevertheless neurological recovery was absent at one year follow-up after surgery.