Many men who undergo vasectomy fail to get the follow-up test that shows whether the procedure worked, a new study suggests.

Researchers at the Cleveland Clinic Foundation found that of 436 vasectomy patients they followed, one-quarter never returned a semen sample to confirm that they were indeed sterile. And half didn’t get a second semen analysis, as their surgeon had advised.

In all, only one-fifth of patients followed the full instructions to have two consecutive sperm-free semen samples in the months following surgery, according to findings published in the journal BJU International.

But much of the problem may be in the post-vasectomy process itself, rather than men’s compliance, study co-author Dr. J. Stephen Jones told Reuters Health.

Most urologists tell their vasectomy patients to have two follow-up tests to make sure their semen does not contain sperm, or at least viable sperm. But there’s no consensus on the necessary number and timing of the tests, Jones said.

Asking men to submit semen samples twice, or sometimes more, may simply be too much, he argued.

And in their study, Jones and his colleagues found evidence that one semen analysis is likely to be enough.

Of the patients who had an initial semen analysis two months after surgery, one-quarter still had sperm in their samples. But in all but three of these 83 men, the sperm were non-mobile, and the large majority had no sperm in semen samples taken one month later. Eventually, all but one became sperm-free.

All of this suggests that one negative sample three months after surgery is enough to confirm a vasectomy’s success, according to the researchers.

Alternatively, a two-month sample free of moving sperm may be adequate - though, Jones said, “that’s the part that will be debatable” among doctors.

Many urologists believe that semen should be free of sperm, and not just mobile sperm, to confirm a vasectomy’s success.

The bottom line for patients, Jones said, is that they should always have a follow-up semen analysis - and that couples should keep using other forms of birth control until that time.

He noted that although the “textbook” statistic indicates that vasectomy procedures rarely fail, in reality the failure rate varies from surgeon to surgeon.

###

SOURCE: BJU International, April 2006.