Does mesh implantation affect the spermatic cord structures after inguinal hernia surgery? An experimental study in rats

Is mesh pore size in polypropylene meshes associated with the outcome in Lichtenstein inguinal hernia repair: a registry-based analysis of 22,141 patients

INTRODUCTION

Experimental data show that large-pored meshes reduce foreign body reaction, inflammation and scar bridging and thus improve mesh integration. However, clinical data on the effect of mesh porosity on the outcome of hernioplasty are limited. This study investigated the relation of pore size in polypropylene meshes to the outcome of Lichtenstein inguinal hernioplasty using data from the Herniamed registry.

METHODS

This analysis of data from the Herniamed registry evaluated perioperative and 1-year follow-up outcomes in patients undergoing elective, primary, unilateral Lichtenstein inguinal hernia repair using polypropylene meshes. Patients operated with a non-polypropylene mesh or a polypropylene mesh with absorbable components were excluded. Polypropylene meshes with a pore size of 1.0 × 1.0 mm or less were defined as small-pored meshes, while a pore size of more than 1.0 × 1.0 mm was considered large-pored. Unadjusted analyses and multivariable analyses were performed to investigate the relation of pore size of polypropylene meshes, patient and surgical characteristics to the outcome parameters.

RESULTS

Data from 22,141 patients were analyzed, of which 6853 (31%) were operated on with a small-pore polypropylene mesh and 15,288 (69%) with a large-pore polypropylene mesh. No association of mesh pore size with intraoperative, general or postoperative complications, recurrence rate or pain requiring treatment was found at 1-year follow-up. A lower risk of complication-related reoperation tended to be associated with small-pore size (p = 0.086). Furthermore, small-pore mesh repair was associated with a lower risk of pain at rest and pain on exertion at 1-year follow-up.

CONCLUSION

The present study could not demonstrate an advantage of large-pore polypropylene meshes for the outcome of Lichtenstein inguinal hernioplasty.

Bilateral inguinal hernia repair and male fertility: a randomized clinical trial comparing Lichtenstein versus laparoscopic transabdominal preperitoneal (TAPP) technique

BACKGROUND

The effects of hernia repair on testicular function remain uncertain, regardless of the technique used. Studies that analyze testicular volume and flow after hernia repair or hormonal measurements are scarce and show contradictory results. This study aimed to evaluate the impact of bilateral inguinal hernia repair on male fertility in surgical patients in whom the Lichtenstein and laparoscopic transabdominal preperitoneal (TAPP) techniques were used.

METHODS

A randomized clinical trial comparing open (Lichtenstein) versus laparoscopic (TAPP) hernia repair using polypropylene mesh was performed in 48 adult patients (20 to 60 years old) with primary bilateral inguinal hernia. Patients were evaluated preoperatively and 90 and 180 postoperative (PO) days. Sex hormones (Testosterone, FSH, LH and SHGB) analysis, testicular ultrasonography, semen quality sexual activity changes and quality of life (QoL) were performed. Postoperative pain was evaluated using the visual analog scale (VAS).

RESULTS

Thirty-seven patients with aged of 44 ± 11 years were included, 19 operated on Lichtenstein and 18 operated on TAPP. The surgical time was similar between techniques. The pain was greater in the Lichtenstein group on the 7th PO day. The biochemical and hormonal analyses, testicular ultrasonography (Doppler, testicular volume, and morphological findings) and sperm quality were similar between groups. However, the sperm morphology was better in the Lichtenstein group after 180 days (p < 0.05 vs. preoperative) and two patients who underwent Lichtenstein hernia repair had oligospermia after 180 days. The QoL evaluation showed a significant improvement after surgery in the following domains: physical function, role emotional, bodily pain and general health (p < 0.05). On comparison of Lichtenstein vs. TAPP none of the domains showed statistically significant differences. No patient reported sexual changes.

CONCLUSION

Bilateral inguinal hernia repair with polypropylene mesh, whether using Lichtenstein or TAPP, does not impair male fertility in terms of long-term outcomes.

TRIAL REGISTRATION

Approved by the Ethics Committee for the Analysis of Research Projects (CAPPesq) of the HC/FMUSP, Number 2.974.457, in June 2015, Registered on Plataforma Brasil in October 2015 under Protocol 45535015.4.0000.0068. Registered on Clinicaltrials.gov, NCT05799742. Enrollment of the first subject in January 2016.

Does the Choice of Suture Materials Affect the Vas Deferens After Hernia Ring Closure in Inguinal Hernia Surgery: An Experimental Study in Rats

INTRODUCTION

Laparoscopic inguinal hernia repair is a commonly performed procedure in children. Currently, monofilament polypropylene and braided silk are the two most frequently used materials. Studies have suggested more tissue inflammatory reactions with the use of multifilament non-absorbable sutures. However, little is known about the effects of suture materials on adjacent vas deferens. The aim of this experiment was to compare the effect of non-absorbable monofilament and multifilament sutures on vas deferens in laparoscopic hernia repair.

METHODS

All animal operations were performed by a single surgeon under aseptic conditions and anaesthesia. Ten male Sprague Dawley rats were divided into two groups. In Group I, "hernia repair" was performed using 5.0 Silk. In Group II, polypropylene sutures (Prolene®; Ethicon, Somerville, N.J., USA) were used. All animals also received sham operations in the left groin as a control. After 14 days, the animals were euthanised and a segment of vas deferens just adjacent to the suture was excised for histological review by an experienced pathologist who was blind to the treatment groups of the respective specimens.

RESULTS

The body sizes of the rats in each group were comparable. Group I had significantly smaller vas deferens than Group II (diameter: 0.2 vs. 0.6 ± 0.2, p = 0.005). Silk sutures appeared to cause more tissue adhesion than Prolene® sutures, as graded by blind assessors (adhesion grade: 2.8 ± 1.3 vs. 1.8 ± 0.8, p = 0.1), although this did not reach statistical significance. There was no significant difference in the histological fibrosis score and inflammation score.

CONCLUSION

The only effect of non-absorbable sutures on vas deferens in this rat model was the reduced cross-sectional area of vas deferens and increased tissue adhesion when using silk sutures. However, there was no significant histological difference in inflammation or fibrosis caused by either material.

Could polypropylene mesh impair male reproductive organs? Experimental study with different methods of implantation

PURPOSE

To evaluate the vas deferens and testicles of rats submitted to bilateral inguinotomy and polypropylene (PP) mesh placement.

METHOD

Sixty Wistar rats were randomized into three groups: Control (inguinotomy only), mesh placement over the vas deferens (Mesh-DD) or under the spermatic funiculus (Mesh-SF). The following analyses were performed: vas deferens morphometry (lumen area and wall thickness), quantification of collagen fibers, spermatogenesis, apoptosis (cleaved caspase-3 and TUNEL) and cellular proliferation (Ki67). Quantitative gene expression (qPCR) for apoptosis and inflammatory cytokines were evaluated by RT-PCR.

RESULTS

In the apoptosis pathway, Mesh-DD showed one upregulated gene (Il10) and three downregulated genes (Fadd, Tnfrsf1b and Xiap). In Mesh-SF, 17 genes were downregulated. In the inflammation pathway (Mesh-DD), one gene was upregulated (Il1r1), and one gene was downregulated (Ccl12). In Mesh-SF, three genes were upregulated (Il1r1, Tnfsf13b and Csf1), and two were downregulated (Ccl12 and Csf2). PP mesh placement preserved spermatogenesis and did not alter the vas deferens or the testicle. In the ductus deferens, there was reduced luminal area (30 days), increased wall thickness (90 days), and increased type III collagen and cell proliferation (30 and 90 days) (p < 0.05). In the testicle, cell proliferation was greater in the Mesh-DD (p < 0.05).

CONCLUSIONS

PP mesh, whether or not in direct contact with spermatic funicular structures, induces changes that were not sufficient to cause damage to the evaluated organs.

Does a bilateral polypropylene mesh alter the duct deferens morphology, testicular size and testosterone levels? Experimental study in rats

Purpose

To evaluate the effect of a PP mesh on duct deferens morphology, testicular size and testosterone levels.

Methods

Forty adult male rats were distributed into groups: 1) no surgery; 2) inguinotomy; 3) mesh placed on the duct deferens; and 4) mesh placed on the spermatic funiculus. After 90 postoperative days, the inguinal region was resected, and blood samples were collected for the measurement of serum testosterone (pg/dl). The ducts deferens were sectioned in three axial sections according to the relationship with the mesh — cranial, medial and caudal. The wall thickness and duct deferens lumen area were measured.

Results

The morphology of the duct deferens was preserved in all groups. The mesh placement did not alter this morphology in any of the analyzed segments. Surgery, with or without mesh placement, did not alter the morphology, wall thickness or lumen area (p>0.05). In all operated groups, serum testosterone levels were similar (p>0.05) but there was a decrease in testicle size (p<0.05).

Conclusion

Surgery, with or without mesh placement, did not alter the morphology of the duct deferens and, although this treatment resulted in testicular size reduction, it did not affect serum testosterone levels.

[Azoospermia and a history of inguinal hernia repair in adult]

BACKGROUND

Inguinal hernia repair is one of the most performed surgeries in the world. It is recognized that any surgery of the pelvic floor may represent a risk factor of male infertility.

METHOD

Retrospective study of patients with azoospermia and a history of adult inguinal hernia repair surgery and referred to our center between January 1990 and January 2011 for infertility.

RESULTS

Among 69 azoospermia patients with history of adult inguinal hernia repair surgery, 60 patients underwent surgical extraction of sperm that was successful in 75% (45/60). Positive extraction rate decreases in the subgroup of patients with risk factors for infertility (61.4%) as well as in the group with bilateral inguinal hernia (67.9%). There was no statistically significant difference in the positive rate of sperm retrieval according to surgical technique or according to the use of polypropylene mesh (P>0.05).

CONCLUSION

The obstruction of the vas deferens due to an inguinal hernia repair was a potential iatrogenic cause of male infertility that was rare and underestimated. The influence of using a polypropylene mesh was not clearly demonstrated. The management of these patients is based on prevention in order to identify patients with risk factors of infertility in order to propose a presurgery cryopreservation of sperm.

LEVEL OF EVIDENCE

5.

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.

Influence of mesh materials on the integrity of the vas deferens following Lichtenstein hernioplasty: an experimental model

BACKGROUND

The utilization of mesh reinforcement of the inguinal area with polypropylene mesh has increased drastically over the last decade. Infertility due to obstructive azoospermia is a rare but serious complication following inguinal hernia repair, especially in young patients. The aim of this study was to evaluate the effect of different mesh structures on integrity of the vas deferens.

MATERIALS AND METHODS

Twenty male Chinchilla rabbits were used. The spermatic cord was dissected free and a Lichtenstein repair was performed with a low-weight polypropylene mesh (UltraPro) and a heavy-weight polypropylene mesh (Prolene) on the contralateral side. A vasography was performed after six months in order to investigate obstructions of the vas deferens. Light microscopy of the mesh host tissue interface was also performed and the foreign body reaction analyzed. Spermatogenesis was evaluated using the Johnsen score.

RESULTS

Vasography revealed relevant obstructions (>75% of lumen diameter) located at the mesh margins (50% of Prolene and 22.2% of UltraPro mesh samples). Microscopic investigation of the mesh-host tissue interface showed typical formation of foreign body granulomas. The diameters of the foreign body granulomas were significantly reduced in the UltraPro mesh group (41.7 +/- 5.5 microm) compared to the Prolene mesh group (48.7 +/- 7.7 microm). Upon investigating the percentages of apoptotic (TUNEL) and proliferating (Ki67) cells, no significant differences were found. Following Prolene mesh implantation, a mean Johnsen score of 9.1 +/- 1.2 was estimated, which was not significantly different from the UltraPro mesh samples (8.9 +/- 1.4, P > 0.05).

CONCLUSIONS

If a mesh material is needed for inguinal hernia repair in young patients, the use of modern low-weight large porous and elastic samples appears to have a beneficial effect on integrity of the vas deferens.

Histopathological alterations of the vas deferens in rats exposed to polypropylene mesh

OBJECTIVE

To assess the histological and physiological effects of polypropylene mesh for inguinal herniorraphy, as it can cause lesions in the vas deferens in 0.3-2.0%, leading to infertility, and induces an inflammatory process and adjacent fibrosis, strengthening the posterior inguinal wall.

MATERIALS AND METHODS

In all, 40 male albino rats (3 months old) had bilateral vas deferens dissection followed by mesh implantation on one side; the contralateral side was used as the control. The rats were killed 90 (group 1) and 120 (group 2) days later, and the vas deferens, epididymides and testicles assessed histopathologically.

RESULTS

There was a foreign-body reaction after mesh implantation, but not in the controls. The mean lumen dilatation in regions proximal to the mesh in groups 1 and 2 was 0.468 and 0.371 mm(2), respectively, and all the sections had spermatozoids. The mean dilatation in control groups 1 and 2 was 0.239 and 0.170 mm(2), respectively, with spermatozoids present in 58% and 75%, respectively (significant, P < 0.05). In group 1 the wall thickness of mesh-implanted segments reduced to 0.177 mm, and in segments proximal to the mesh to 0.099 mm; the control segment was 0.298 mm (P < 0.05). In group 2 the mean thickness of mesh-implanted and proximal segments was 0.134 and 0.224 mm, respectively, while in the control it was 0.284 mm (not significant). There was loss of mucosal folding in all segments proximal to the mesh but not in the control. The epididymides and testicles were unchanged.

CONCLUSION

Polypropylene mesh induces a foreign-body reaction, with histological changes in the vas deferens that cause functional obstruction, with dilatation and spermatozoid repression.

Influence of hernioplastic implants on male fertility in rats

This study explored the vulnerability of the ductus deferens due to mesh induced inflammation and shrinkage after hernia repair in the rodent model. Two commonly used types of hernioplastic implants (Prolene and Vypro II) were surgically wrapped around the ductus deferentes on both sides in 20 juvenile and 20 adult Sprague-Dawley rats. Twenty male rats underwent sham surgeries as controls. After 3 months, each male was mated with 2-3 adult females, which were subsequently sacrificed and oocytes or embryos were flushed and counted. Histochemical investigations of the implants and the ductus recovered surgically 4 weeks after implantation (one side) and after the fertility test (second side) were conducted. All groups exhibited 1-3 males with decreased or restricted fertility but there was no difference between groups. Histochemical analysis of the implants and the ductus recovered 4 weeks and 4 months after implantation revealed some sperm granulomes due to lesions of the spermatic cord caused by the implant in the Prolene group. There was no inflammatory reaction in the mucosa or blockage of the spermatic cord visible. Both types of hernioplastic implants tested in this investigation do not give an indication of a negative influence on male fertility in juvenile or adult rats.

The influence of inguinal mesh repair on the spermatic cord: a pilot study in the rabbit

The permanent implantation of a polypropylene mesh during inguinal hernia repair causes chronic inflammatory changes in the surrounding tissue. We investigated the effect of this foreign body reaction on the structures of the spermatic cord in the rabbit. Eight Chinchilla rabbits underwent unilateral inguinal hernia repair by the Lichtenstein technique using Marlex (n = 4) or Ultrapro (n = 4) mesh. The contralateral side was operated upon using the Shouldice repair. Three animals served as controls. Three months after operation we analyzed testicular size, testicular temperature, and arterial perfusion by excitation light of a 780-nm laser after injection of 0.5 mg/kg indocyanin green. Histological evaluation included spermatogenesis (Johnsen score) and foreign-body reaction. Testicular volume increased about 10% after each operation. The decrease of arterial perfusion and testicular temperature was more significant after mesh repair than following Shouldice operation. After mesh implantation we found fewer seminiferous tubules classified as Johnsen 10 (Marlex: 51.3%, Ultrapro: 45.0%) than after Shouldice repair (63.8%) or in the controls (65.8%). The spermatic cord showed a typical foreign-body reaction at the interface between mesh and surrounding tissue, which was not detectable after Shouldice repair. Preserved cremasteric muscle fibers protected the structures of the spermatic cord. The inflammatory foreign-body reaction of the surrounding tissue induced by the inguinal prosthetic mesh includes the structures of the spermatic cord. This may have an influence also on spermatogenesis. Therefore, we recommend strict indications for implantation of a prosthetic mesh during inguinal hernia repair.