Among infertile men, testicular hypotrophy is about twice as common in men with varicoceles as in those without varicoceles.
"Approximately 35% of men with infertility have varicoceles," said first author Sutchin R. Patel, MD, a urology resident at Brown University, Providence, RI, collaborating with Mark Sigman, MD. "Testicular hypotrophy is a recognized finding in these patients, and men with varicoceles and testicular hypotrophy have worse semen parameters than men without testicular hypotrophy.
"While testicular hypotrophy is also recognized to occur in patients without varicoceles, the prevalence of hypotrophy in this population compared to those patients with varicoceles is unknown."
Testicular hypotrophy was present in 705 (22%) of the 3,202 men. A total of 1,105 men (34.5%) presented with a clinical varicocele. Among those men, the varicocele was left-sided only in 893 men (81%), right-sided only in 20 men (2%), and bilateral in 192 (17%).
Testicular hypotrophy was found in 352 (32%) of 1,105 men with any varicocele versus in only 353 (17%) of the 2,097 men without varicocele. Left-sided hypotrophy was more common than right-sided hypotrophy (89% vs. 11%), and left-sided hypotrophy was more common in patients with a varicocele compared to those without (30% vs. 13%, p<.001).
The men with varicocele also were subcategorized into three groups based on varicocele size assessed during the physical exam (ie, small, medium, large). Comparison of testicular volume differential and varicocele size showed a statistically significant association. Mean volume differential was 1.07 mL in men with no varicocele, increased to 1.49 mL in those with a small varicocele, and was 4.54 mL in the large varicocele group.
Analyses showed that among the 352 men with varicocele(s) and testicular hypotrophy, left testicular hypotrophy was more common than right hypotrophy, regardless of the side of the varicocele.
"Understanding why hypotrophy seems to affect the left testicle more than the right in men with a varicocele and why right varicocele is associated with left-sided hypotrophy are topics requiring more study," Dr. Patel said.
Among the 287 men with a left varicocele and hypotrophy, 89% had left hypotrophy and 11% had right hypotrophy. Only five men had a unilateral right varicocele, and in all of those patients, testicular hypotrophy was left-sided. Sixty men had both bilateral varicocele and hypotrophy; 92% of these men had left-sided hypotrophy and 8% had right-sided hypotrophy.
Overall, only 20 men in the study had a right varicocele, and the proportion of these men with hypotrophy was not significantly different from patients with no varicocele (25% vs. 17%, respectively).
"Failure to find a significant difference in the incidence of hypotrophy may be due to inadequate power because of the small number of patients with a right varicocele. Further study seems warranted," Dr. Patel said.