Pudendal Nerve Entrapment as Source of Intractable Perineal Pain

Perineal pain caused by pudendal nerve entrapment is a rarely reported entity, with only a handful of cases in the modern literature. A 25-yr-old male medical student had refractory unilateral orchialgia for 32 mo and concomitant proctalgia for 14 mo. Pain was positional in nature, exacerbated by sitting and partially relieved when standing or recumbent. Pudendal nerve entrapment was diagnosed clinically, with computed tomography-guided nerve blocks providing temporary relief. A prolonged left pudendal nerve distal motor latency on electrodiagnostic testing later confirmed the diagnosis. At surgery, the left pudendal nerve was found flattened in the pudendal canal of Alcock and in contact with the sharp inferior border of the sacrospinous ligament. After surgical decompression and rehabilitation, the patient experienced significant relief of pain and returned to medical school. This case suggests pudendal nerve entrapment should be considered in the differential diagnosis of chronic urogenital or anorectal pain, particularly if the pain is aggravated by sitting or if there is a history of bicycle riding.