Rare non-motile sperm points to vasectomy success

October 1, 2004

Toronto--Patients who show evidence of rare non-motile sperm after undergoing vasectomy will eventually become azoospermic-marking vasectomy success. However, patient compliance post-vasectomy remains low, despite aggressive pre- and postoperative counseling, University of Toronto researchers report.

Toronto-Patients who show evidence of rare non-motile sperm after undergoing vasectomy will eventually become azoospermic-marking vasectomy success. However, patient compliance post-vasectomy remains low, despite aggressive pre- and postoperative counseling, University of Toronto researchers report.

"Some clinicians have proposed achieving azoospermia is not necessary to declare that a vasectomy is successful. They argue that a large component of patients who submit post-vasectomy semen analysis demonstrate rare non-motile sperm, and that this rare non-motile sperm may in fact have limited fertility potential," said Ashis K. Chawla, MD, a resident at the University of Toronto's Murray Koffler Urologic Wellness Centre working with Armand Zini, MD. "This becomes an issue for patient compliance, when patients are required to use an alternate form of contraception until they are deemed to be azoospermic."

Patient compliance The Toronto team set out to examine patient compliance rates with post-vasectomy semen analysis testing, as well as the clinical significance of rare non-motile sperm in the post-vasectomy semen analysis. They performed a retrospective chart review of 690 patients who underwent a no-scalpel vasectomy procedure between 1996 and 2002.

Of the 690 patients, 315 (45%) failed to follow-up at all with semen analysis, Dr. Chawla reported. Of those patients who did follow-up, 295 submitted two semen analyses as requested, and 80 submitted only one.

Of the 295 patients who correctly submitted two semen analyses, 156 (60%) were found to be azoospermic, and 110 (37%) had rare non-motile sperm. Of the 110 men with rare non-motile sperm, 62 of these patients-representing 75%-ultimately became azoospermic.

Rare non-motile sperm With respect to rare non-motile sperm, it's obvious that the majority of men with rare non-motile sperm after vasectomy eventually became azoospermic, Dr. Chawla pointed out.

"We propose that the finding of rare non-motile sperm is consistent with a successful vasectomy," he said. "We caution though that the failure rate associated with rare non-motile sperm is roughly 1%.

"Based on this, we feel that prospective long-term studies are further needed to assess a true risk of late failure based on early post-vasectomy semen analysis."

Dr. Chawla added that the high rate of non-compliance is something to be concerned with, as vasectomy failure is still possible without patient follow-up and semen analysis.

"Despite aggressive counseling, we can see that patient compliance with a post-vasectomy protocol was still quite poor. Over 45% of our patients failed to submit a post-op semen analysis," he said. "Our vasectomy failure rate was seen in two out of 295 patients that submitted two semen analyses, and this represented 0.6% of the population. This is in keeping with current published rates."