Vasectomy Causes Testicular Damage

Vasectomy is frequently described as a simple, convenient, inexpensive, permanent surgical birth control method for men. Approximately 500,000 vasectomies are performed in the United States each year. Another 40,000 are performed in the United Kingdom, with thousands more performed worldwide. Vasectomy is widely accepted as a safe procedure with acceptable short-term side effects (primarily bleeding or infection) and few long-term side effects. Chronic post-vasectomy scrotal or testicular pain is well described in the medical literature, but is not prominently featured on vasectomy consent forms. Testicular damage due to vasectomy has been a concern, but this information has not made its way into the pre-vasectomy consent process.

Testicular damage is well documented in all mammalian vasectomy models studied to date, including rodents (rabbits, rats, mice, hamsters, and guinea pigs), canines, non-human primates, and other mammals (sheep, horses, and others). There are studies in humans showing testicular damage (testicular fibrosis) after vasectomy that date back to 1985. See this reference from The New England Journal of Medicine.

“To determine whether there are any deleterious changes in the human testis after vasectomy, we obtained testicular biopsy specimens from 31 healthy men undergoing vasectomy reversal and from 21 healthy, fertile volunteers. Morphometric analyses of these specimens revealed a 100 per cent increase in the thickness of the seminiferous tubular walls (P less than 0.001), a 50 per cent increase in the mean cross-sectional tubular area (P less than 0.001), and a significant reduction in the mean number of Sertoli cells (P less than 0.01) and spermatids (P less than 0.01) per tubular cross section in the post-vasectomy group, as compared with the control group. Focal interstitial fibrosis was observed in 23 per cent of the specimens from the post-vasectomy group and in none from the control group.We conclude that significant morphologic changes occur in the human testis after vasectomy. The presence of focal interstitial fibrosis was associated with a high incidence of infertility in this series. There was a significant correlation (P less than 0.01) between interstitial fibrosis and infertility in patients who underwent a surgically successful vasectomy reversal (sperm in the ejaculate). None of the other measured characteristics correlated with infertility after vasectomy reversal.

Focal interstitial fibrosis is essentially scar tissue. The pressure-induced effects of closing off the sperm delivery system could cause this scarring by interrupting the flow of sperm through the vas deferens (the “tubes” that are cut during vasectomy). An alternate hypothesis supported by animal studies suggest that the fibrosis is caused by inflammation due to an auto-immune reaction to sperm or sperm components after disruption of the blood/testes barrier that is induced by vasectomy (see my other article on the immunologic effects of vasectomy).