Is there a risk of infertility after inguinal mesh repair? Experimental studies in the pig and the rabbit

Abstract

The implantation of a non-absorbable polypropylene mesh during hernia repair causes chronic foreign body reaction involving the surrounding tissue. In case of inguinal hernia repair using mesh techniques, the spermatic cord is potentially affected by this chronic inflammatory tissue remodeling. This effect has been investigated using standardized animal models (pig and rabbit). Fifteen adult male pigs underwent transinguinal preperitoneal implantation of a polypropylene mesh. The contralateral side with a Shouldice repair served as control. After 7, 14, 21, 28, and 35 days, three animals were sacrificed. The spermatic cords were resected and analyzed histologically. In a second experiment Lichtenstein repair using the same polypropylene mesh and Shouldice repair on the contralateral side was done in eight chinchilla rabbits. Three animals served as controls. Three months after operation, the analysis included testicular size, testicular temperature, and testicular and spermatic cord perfusion. We added histological evaluation of the foreign body reaction and the spermatogenesis using the Johnsen score. In the pig, we observed a certain foreign body reaction with diffuse infiltrating inflammatory cells after mesh implantation. Venous thrombosis of the spermatic veins occurred in five of 15 cases. One animal presented focal fibrinoid necrosis of the deferent duct wall. The side of Shouldice repair showed only minor postoperative changes. In the rabbit, we also observed a typical foreign body reaction at the interface between mesh and surrounding tissue, which was not detectable after Shouldice repair. The mesh repair led to a decrease of arterial perfusion, testicular temperature, and the rate of seminiferus tubules with regular spermatogenesis classified as Johnsen 10 (Lichtenstein: 48.1%, Shouldice: 63.8%, controls: 65.8%). Testicular volume increased about 10% after each operation. The implantation of a polypropylene mesh in the inguinal region induces major response of the structures of the spermatic cord. This may have an influence also on spermatogenesis. Due to this a strict indication for implantation of a prosthetic mesh during inguinal hernia repair is recommended.

Does the presence of a mesh have an effect on the testicular blood flow after surgical repair of indirect inguinal hernia?

“…4,5 A few animal studies on the inflammatory reaction of the mesh have been reported. Peiper et al 6 have found that inflammatory changes develop within 1-12 weeks. Another study reported increasing foreign body reaction to preperitoneal polyprolene mesh until the third week after implantation in pigs.…”

Male infertility after mesh hernia repair: A prospective study

“…The risk for infertility after mesh repair, as proposed by other authors 4,5,9,10 , has been regarded as an important question. Our results indicate that at the informed consent, the surgeon should not focus on the infertility problem.…”

“…In contrast others have found proximal dilatation but no thickening of the wall of the vas deferens 2 . Decreased arterial perfusion in the testis 5,7 and spermatic venous thrombosis 4 have also been reported.. One study has shown beneficial effects on the integrity of the vas deferens when using lightweight mesh 3 whereas another study did not find any difference in inflammation and fibrosis comparing heavyweight with lightweight mesh 8 .…”

“…In mesh operations, the recommendation of using the intact cremasteric muscle as a protective layer for the spermatic cord structures is theoretically preferable and recommended by some 4 .…”

“…There has also been discussion whether or not the proposed risk is of such importance that some or all patients undergoing hernia surgery should be informed in detail preoperatively, even if this may cause some to choose a method associated with greater risk for recurrence and long-term pain 10,11 . Recommendations have also been made to leave the cremaster muscle intact as a protective layer 4 and to dissect the spermatic cord carefully and meticulously, to avoid damaging its structures 13 . A technique for reestablishing patency in the vas deferens has also been described 14 .…”