Varicocele, hypoxia and male infertility. Fluid Mechanics analysis of the impaired testicular venous drainage system.

Background: Varicocele is a bilateral vascular disease, involving a network of collaterals and small, retroperitoneal bypasses. The right and the left testicular venous drainage systems are complex and not identical to each other. It was considered a predominantly unilateral (left-sided) disease. Its pathophysiology has not been clearly delineated and the treatments offered do not seem to be effective. The medical literature is replete with articles demonstrating inconsistent and even contradictory results which have led clinicians to dissociate varicocele from male infertility. Since male fertility is preserved with only one healthy testis, male infertility perforce represents bilateral testicular dysfunction. This poses an enigma to clinicians: How can left-sided varicocele causes bilateral testicular dysfunction?

Methods: We investigated the internal spermatic veins by venography to understand testicular damage due to varicocele. A total of 740 venographies of the internal spermatic veins (ISVs) were performed, with sclerotherapy of the ISV as treatment for varicocele. Epon-embedded testicular tissue sections were used to identify blood stagnation in the testis.

Results: Varicocele is predominantly a bilateral disease in 84% of cases, associated with collaterals and retroperitoneal venous bypasses in 70% in the left side and 75% in the right side. Histopathology demonstrate stagnation in the testicular microcirculation and hypoxic-ischaemic degenerative changes in all cells' types in the sperms' production site.

Conclusion: Based on our findings (i) varicocele is a bilateral disease; (ii) the disease is expressed earlier in the left side and is more intense because the blood column is longer in the left side than the right; (iii) partial treatment to the left side only and ignoring bypasses is not adequate to correct the problem; (iv) hypoxia leading to ischaemic damage to both testes is the effect of varicocele due to hydrostatic pressures in the impaired venous drainage system, which exceeds the pressures in the testicular arterial microcirculation due to blood columns produced in the disease; (v) hydrostatic pressure does not depend on vein diameter but on blood column height, only; and (vi) thermography alone or combined with ultrasonography with special attention to the bilaterality of the disease are the best non-invasive tools for its detection.