Sperm motility predicts fertility after embolization

By Anthony J. Brown, MD

NEW YORK (Reuters Health) - Men who have a high degree of sperm motility before undergoing spermatic vein embolization to correct a varicocele identifies patients who are likely to experience improved fertility, new research suggests.

In the study, roughly one quarter of infertile men achieved a pregnancy after undergoing the procedure, according to the findings presented Tuesday at the annual meeting of the Radiological Society of North America in Chicago.

Spermatic vein embolization is a nonsurgical, catheter-based technique conducted by interventional radiologists to correct varicoceles. Blood normally flows out from the testicles through a network of small veins that drain into a larger vein passing through the abdomen. Valves in the vein usually prevent the blood flow from reversing back. But sometimes the valves fail and the reversed blood flow stretches and enlarges small veins around the testicle to cause a varicocele.

Up to 15 percent of men in the US have varicoceles, and the conventional wisdom is that they decrease fertility by raising the temperature of the scrotum so sperm development is impaired. However, a few recent reports have questioned this association, showing that varicocele treatment does not improve fertility. The new findings suggest that this treatment will work, provided that pretreatment sperm motility is high.

"Spermatic vein embolization is not a new treatment for varicoceles, but there is still some debate whether it should be performed" just to restore fertility, lead investigator Dr. Sebastian Flacke, from the University of Bonn in Germany, told Reuters Health.

In agreement with other reports, "our study shows that spermatic vein embolization can have a beneficial effect on sperm," he noted. "What's new about our study is that we identified sperm motility as a predictor of when this treatment is likely to improve fertility."

The findings are based on a study of 223 infertile men who had at least one varicocele and were trying to achieve a pregnancy with a healthy partner.

Spermatic vein embolization was associated with a technical success rate of over 99 percent, the report indicates. Semen analysis performed on 173 men at 3 months indicated significant improvements in sperm motility and count. A pregnancy rate of 26 percent was noted at 6-month follow-up.

As noted, high sperm motility was the only significant pre-treatment predictor of achieving pregnancy following embolization.

Flacke said that the 26-percent pregnancy rate seen in the present study is on the low end of what has been reported previously. He attributes this to the fact that many of the men in his team "were very infertile with none of them having normal-appearing sperm. So, even in men with severe infertility, this procedure offers some chance of achieving pregnancy."

To verify the fertility benefits of spermatic vein embolization in varicocele patients, Flacke called for trials incorporating an untreated control group.