The problem can raise the temperature of the scrotum by a couple of degrees, impairing normal sperm function. The procedure, called varicocele repair, is designed to restore healthy blood flow to the organs and bring their temperature down into the normal range. But the latest findings suggest that the operation doesn't deliver.
However, some experts say the latest research focused on versions of the technique -- the most common fertility operation among men in the United States -- that are now obsolete and which may in fact lower the odds of conception.
"I would expect many of these operations to make the patient worse," says Dr. Marc Goldstein, a urologist in New York City and an expert in varicocele repair.
Goldstein, a professor of reproductive medicine and urology at Weill Medical College of Cornell University, helped pioneer a less-invasive form of the surgery in the 1980s that he says has much better outcomes than the conventional approach.
Varicoceles (pronounced vahr-ih-co-seals) are the same as varicose veins in the legs. They occur in about 15 percent of men. Many have no fertility problems as a result, but the swollen veins are believed to play a role in as many as 40 percent of cases of impaired fertility (also known as subfertility). Some men with the problem have slower sperm with abnormal shapes that may have trouble fertilizing an egg.
Removing the offending vessels can correct these problems -- or so the theory goes.
In the new work, appearing in the May 31 issue of The Lancet, researchers in Holland and Canada analyzed seven earlier studies on varicocele repair conducted between 1979 and 2002. Compared with untreated men, those who had the operation were no more likely to conceive.
The researchers say the limited number of patients might have obscured small effects in various sub-groups of men. Still, they say, "varicocele repair does not seem to be an effective treatment for male or unexplained subfertility."
Dr. Joel Marmar, who invented the microsurgery form of varicocele repair, says the new study has deep flaws. Some included men whose varicoceles didn't meet more recent criteria for who is most eligible for the procedure, he says. And almost none of the previous trials had any information about the woman's age or the nature of her fertility problems, if any -- information that's vital when pregnancy is the desired outcome.
"With pregnancy you're introducing a totally different variable: the wife," says Marmar, a professor of urology at the Robert Wood Johnson Medical School in Camden, N.J.