Some risks associated with vasectomy include:
Bleeding can occur during or after vasectomy by either method, but it is less common with No Scalpel Vasectomy. If this occurs within the scrotum, drainage of a scrotal hematoma (blood clot) in a hospital operating room could be necessary. Smaller hematomas do not require surgical drainage, but tender swelling can last for 2 to 4 weeks. Both large and small hematomas are very rare.
Infection is also a rare complication with an infection rate of approximately 1 in 4000.
Sperm granuloma is a pea-sized tender lump on the vas tube at the vasectomy site, almost never requiring treatment. Periodic tenderness usually responds to an anti-inflammatory medication like ibuprofen.
Congestion and tenderness from the buildup of sperm and white blood cells upstream from (or at) the vasectomy site, can occur any time after vasectomy, but usually goes away with the use of an anti-inflammatory drug such as aspirin or ibuprofen. About one in 2000 patients will experience chronic post-vasectomy discomfort (PVPS or Post-Vasectomy Pain Syndrome) severe enough that he will seek vasectomy reversal. A larger percentage may have milder forms of chronic pain that can affect the quality of life but not severely enough to seek vasectomy reversal.
Recanalization is the development of a channel of sperm flow between the two cut ends of the vas. If this happens during the healing process, the semen never becomes sperm-free until the vasectomy is repeated.