Post-vasectomy sample at 16 weeks is sufficient to establish sterility

August 15, 2007

Urologists attending this year's AUA annual meeting benefited from a wealth of cutting-edge research on the diagnosis and treatment of male infertility.

A single azoospermic sample at 16 weeks should be sufficient to establish post-vasectomy sterility.

Urologists are understandably quite sensitive to the litigation risk surrounding failed vasectomy, especially given the relatively low compliance of men who are asked to supply semen samples after the procedure.

"Interestingly, they found that only 1% of men with rare, non-motile sperm will ultimately fail," Dr. Niederberger said. "We as urologists really beat ourselves up over things like rare, non-motile sperm, but, all things considered, vasectomy is still one of the most efficacious means of contraception. We should feel comfortable about that."

Dr. Niederberger labeled the British study the best meta-analysis on this topic since an Australian group, using similar methods, suggested that a single azoospermic sample after 3 months and 20 ejaculations is a useful protocol (J Urol 2005; 174:29-36).

There does not appear to be a difference in Kruger strict morphology between fertile and infertile men.

For 60 years, morphology has been a commonly used method to evaluate the form and structure of sperm. In the 1990s, morphology was further refined by "strict" criteria. But the clinical utility of strict morphology in the evaluation of infertile men has come into question in recent years, leading to the formation of two opposing factions, Dr. Niederberger notes.

"One camp says that if you did a better job performing the Kruger test, you would get more meaningful results," he said. "The other camp says the test itself isn't particularly meaningful."

The latter group received some support in a joint study from the Baylor College of Medicine, Houston, and the Naval Medical Center in San Diego. The study found that men with proven fertility have a high frequency (56%) of abnormal strict morphology "that is not significantly different from infertile males." The authors went on to say that strict morphology "likely represents a heterogeneous and non-specific surrogate marker of abnormal sperm fertilization capacity."

"Here we have an outstanding lab questioning the utility of the test itself," Dr. Niederberger said. "You don't want to necessarily write off all sperm that look funny to you, but there are caveats. For example, if the sperm all look abnormal in the same way-say, all with perfectly round heads and thus missing acrosomes-clearly that will affect male fertility. But those conditions are rare."

Osteopenia is found in a significant percentage of infertile men with sperm counts below 5 million.

Decreased bone mineral density is common in elderly and hypogonadal men, but little has been known about the incidence of that condition in the infertile male population. In a prospective study of 46 patients presenting for infertility evaluation, a group from Brown University, Providence, RI, found that the incidence of osteopenia was 9% (rising to 21% in severely oligospermic men).

The implications of that finding for practicing urologists are profound, Dr. Niederberger believes.