[Perineal neuralgia and Alcock's canal syndrome]

Perineal neuralgia is characterised clinically by pain (burning type of perineal pain) exacerbated in the sitting position. It is secondary to impairment of the internal pudendal nerve in its musculo-osteo-aponeurotic tunnel composed by the ischium and the obturator internus muscle (ischiorectal fossa or pudendal canal). As in any nerve tunnel syndrome, pre-existing neuropathy constitutes a predisposing factor and should therefore be identified. The diagnosis of pudendal tunnel syndrome is confirmed by perineal electrophysiological investigations (detection of neurogenic muscles of the perineal floor, increased sacral latency). Treatment consists of infiltration, possible repeated, of the pudendal tunnel with a sustained-release corticosteroid under CT guidance.