Perineal pain and inferior cluneal nerves: anatomy and surgery

Neuropathic perineal pains are generally linked to suffering of the pudendal nerve. But some patients present pains described as a type of burning sensation located more laterally on the anal margin and on areas including the scrotum or the labiae majorae, the caudal and medial parts of the buttock and the upper part of the thigh. These pains extend beyond the territory of the pudendal nerve. It is interesting to note that the inferior cluneal nerves are responsible for the cutaneous sensitivity in the inferior part of the buttock. We wanted to check if these nerves, or some of their branches, could be responsible for such pains. An anatomic study, containing six dissections on corpse, has been conducted. The inferior cluneal nerves, emerging from the posterior femoral cutaneous nerve have some branches joining the perineum, especially by a perineal ramus. However, two conflict areas have been identified on the path of these nerves and on the perineal ramus: one at the level of the sacrotuberal ligament, and the other being the passage under the ischium. Two surgical approaches have been established from these observations with the aim of suppressing the conflicts.