Pudendal Nerve Entrapment Syndrome

Pudendal neuralgia caused by pudendal nerve entrapment (PNE) is a chronic and severely disabling neuropathic pain syndrome.[1] It presents in the pudendal nerve region and affects both males and females. It is mostly underdiagnosed and inappropriately treated, and causes significant impairment of quality of life. Anatomy of the Pudendal Nerve: The pudendal nerve emerges from the S2, S3, and S4 roots' ventral rami of the sacral plexus. It carries sensory, motor, and autonomic fibers, however an injury to the pudendal nerve causes sensory deficits more than motor. It courses between two muscles, piriformis and coccygeus muscles. It departs the pelvic cavity through the greater sciatic foramen ventral to the sacrotuberous ligament. At the ischial spine level, it passes medial to and under the sacrospinous ligament to re-enter the pelvic cavity through a lesser sciatic foramen. The pudendal nerve then courses in the pudendal canal, which is also called the Alcock canal. The three last branches of the pudendal nerve terminate in the ischioanal fossa. These are the inferior rectal branch, perineal branch, and dorsal sensory nerve of the penis or clitoris. However, there are case reports which have shown variability in the anatomy of the pudendal nerve.[2][3] Pudendal nerve compression based on anatomy[4][5]: The pudendal nerve entrapment syndromes subdivide into four types based on the level of compression. Type I - Entrapment below the piriformis muscle as the pudendal nerve exits greater sciatic notch. Type II - Entrapment between sacrospinous and sacrotuberous ligaments - this is the most common cause of nerve entrapment. Type III - Entrapment in the Alcock canal. Type IV - Entrapment of terminal branches.