The infrapiriformis foramen syndrome resulting from intragluteal injection.

The authors describe a syndrome resulting from a lesion at the level of the infrapiriform foramen due to intramuscular injection, with involvement of the sciatic nerve, the inferior gluteal nerve, the posterior femoral cutaneous nerve and the pudendal nerve. This appears to be the first case of a complete syndrome of the infrapiriform foramen to be reported. In a second case the pudendal nerve was not involved and a releasing neurolysis was performed with remarkable postoperative relief. All the reported cases with involvement of the inferior gluteal nerve are associated with a more or less complete injury of the sciatic nerve. Conversely, the cases of injection injury to the superior gluteal nerve are rarely associated with injury of the sciatic nerve. The anatomic reasons that might explain both kinds of lesion are given. Finally some aspects of 131 cases of sciatic paralysis resulting from injection are also examined.