Damage to the spermatic cord by the Lichtenstein and TAPP procedures in a pig model.

Background: Mesh implantation is regarded as the standard treatment of inguinal hernias. Obstructive azoospermia induced by mesh implantation is a rare but serious complication. Whether different operative techniques or mesh materials used have an effect on the integrity of the testicle and spermatic cord remains unclear.
Materials: In 12 minipigs a bilateral inguinal hernia repair, either open or laparoscopic, was performed using a standard small-pore polypropylene (PP) or large-pore polyvinyliden fluoride (PVDF) mesh. Next to measurement of the testicular size, thermography of the groin and testicle as a parameter for perfusion was performed preoperatively and at a follow-up at 6 months. Obstructions of the vas deferens were estimated radiographically. Testicular function (Johnson score) and mesh integration (granuloma size, apoptotic cells) were analyzed histologically.
Results: Mean testicular size did not change significantly in follow-up compared to preoperative values. Technique and mesh material used failed to have a significant influence. Thermography of the groin following the Lichtenstein technique had significantly higher values at follow-up regardless of the mesh used. This could not been shown for laparoscopic treatment. Thermographic measurements at the testicle showed a significantly increased temperature in all groups compared to preoperative measurements. Only the Lichtenstein PP group showed significantly decreased values in testicular function. Quantity and quality of obstructions seen at vasography were most detectable in the Lichtenstein PP group. There was significantly decreased granuloma formation following PVDF mesh implantation compared to the PP mesh group regardless of the technique used.
Conclusions: Both the technique and the mesh material have an impact on integrity of spermatic cord and testicular function. According to the results of this study, the laparoscopic TAPP procedure using a large-pore PVDF mesh has the least effect compared to preoperative values.