Post-vasectomy pain syndrome

Overview
Post-Vasectomy Pain Syndrome (PVPS, PVP, CPTP, CPVSP) is a chronic pain condition, marked by severe and unremitting pain, that affects between 5% to 33% of vasectomized men. The pain syndrome is caused by a combination of testicular backpressure, chronic inflammation, fibrosis, sperm granulomas, nerve entrapment, and electrical activity changes in the vas deferens. When pain in the epididymides is the primary symptom, Post-Vasectomy Pain Syndrome is also known as congestive epididymitis.

Backpressure and Distension
There is a marked increase in pressure within the vas on the testicular side following vasectomy. The epididymides of vasectomized men are often swollen and distended from backpressure effects. The efferent ducts and seminiferous tubules of the testes are also impacted by backpressure, leading to an increase in area and thickness.

Inflammation and Fibrosis
As part of the reaction of the body to the injury of vasectomy, the body produces hard scar-like tissue. Simply clamping the vas deferens can produce muscle disruption and fibrosis. As the diameter of the vas lumen is less than the thickness of the wall, the thick muscle layers can easily become disrupted, leading to sperm accumulation and extravasation. Cysts often form from the fluid that spreads between the muscle layers.

Escaping Sperm and Sperm Granulomas
Sperm leak from the vas deferens and epididymides of vasectomized men, forming lesions in the scrotum known as sperm granulomas. Some sperm granulomas can be painful. Interestingly, sperm granulomas can actually reduce the likelihood of PVPS by serving as a pressure valve.

Nerve Entrapment
Nerves can become trapped in the fibrous tissue caused by vasectomy. This pain is often heightened during intercourse and ejaculation because, with arousal and ejaculation, muscles elevate the testis. A large number of nerves that run parallel to the vas are easily cut or damaged during vasectomy.

Electrical Activity Changes
The vas deferens has two forms of electrical activity, pacesetter potentials and action potentials. After vasectomy, while the action potentials are completely diminished, the pacesetter potentials on the testicular side exhibit an irregular rhythm, or vasoarrhythmia.