Microbiology of chronic mesh infection.

PURPOSE: Mesh infection following hernia repair is one of the most dreaded complications of hernia surgery. Mesh sinus, infected seromas, mesh extrusion, and mesh-related enteric fistulas are common complications associated with synthetic mesh. This study aimed to review the microbiota of mesh infection in 100 patients submitted to mesh explantation. METHODS: We reviewed the charts of patients presenting with a history of mesh infection lasting or arising six months or more after mesh placement. All patients who submitted to abdominal wall repair with complete removal of an infected mesh and presenting a positive culture were included. The microbiology analysis was based on positive cultures obtained from the fluids and tissues surrounding the mesh or positive cultures of the mesh. Microorganisms were divided into gram-positive or gram-negative, aerobic or anaerobic, and fungi. RESULTS: Pure aerobic gram-positive cultures were encountered in 50% of the patients, followed by a combination of aerobic gram-positive/gram-negative (8%) and pure gram-negative cultures (6%). Anaerobes were recovered from 31% of patients. Fungi were recovered from 6%. Staphylococcus aureus was identified in 64% of cultures, with methicillin-resistant Staphylococcus aureus present in 42% and methicillin-sensitive Staphylococcus aureus in 22%. Among aerobic gram-negative infections, six (17%) were caused by multi-resistant bacteria, including Pseudomonas aeruginosa, Proteus mirabilis, Acinetobacter baumanii, Klebsiella pneumoniae complex, and Enterobacter cloacae complex. CONCLUSION: Staphylococcus aureus plays a significant role in the pathogenesis of synthetic mesh infection. Staphylococcus aureus, isolated in 64% of cultures, accounted for most single bacterial infections and was the prevalent germ in mesh sinus and infected seromas. Gram-negative infection occurred in 35%. Anaerobes occurred in 31%, commonly encountered in polymicrobial infections. Most fungi cultures happened in patients with enteric fistulas.

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.

The use of synthetic mesh in contaminated and infected abdominal wall repairs: challenging the dogma-A long-term prospective clinical trial.

BACKGROUND: Abdominal wall reconstruction in patients presenting with enteric fistulas and mesh infection is challenging. There is a consensus that synthetic mesh must be avoided in infected operations, and the alternatives to using synthetic mesh, such as component separation techniques and biologic mesh, present disappointing results with expressive wound infection and hernia recurrence rates. METHODS: A prospective clinical trial designed to evaluate the short- and long-term outcomes of 40 patients submitted to elective abdominal wall repair with synthetic mesh in the dirty-infected setting, and compared to a cohort of 40 patients submitted to clean ventral hernia repairs. Patients in both groups were submitted to a single-staged repair using onlay polypropylene mesh reinforcement. RESULTS: Groups' characteristics were similar. There were 13 (32.5%) surgical site occurrences in the infected mesh (IM) group, compared to 11 (27.5%) in the clean-control (CC) group, p = 0.626. The 30-day surgical site infection rate was 15% for the IM group vs. 10% for the CC cases, p = 0.499. One patient required a complete mesh removal in each group. The mean overall follow-up was 50.2 ± 14.8 months, with 36 patients in the IM group and 38 clean-controls completing a follow-up of 36 months. There was one hernia recurrence (4.2%) in the IM group and no recurrences in the CC group. CONCLUSION: We demonstrated that using polypropylene mesh in the infected setting presented similar outcomes to clean repairs. The use of synthetic mesh in the onlay position resulted in a safe and durable abdominal wall reconstruction. TRIAL REGISTRATION: Study registered at Plataforma Brasil (plataformabrasil.saude.gov.br), CAAE 30836614.7.0000.0068. Study registered at Clinical Trials (clinicaltrials.gov), Identifier NCT03702153.

A retrospective review and observations over a 16-year clinical experience on the surgical treatment of chronic mesh infection. What about replacing a synthetic mesh on the infected surgical field?

PURPOSE: To review the short- and long-term results in patients who underwent removal of infected or exposed mesh and reconstruction of the abdominal wall with simultaneous mesh replacement. METHODS: Patients undergoing removal of an infected or exposed mesh and single-staged reconstruction of the abdominal wall with synthetic mesh replacement over a 16-year period were retrospectively reviewed from a prospectively maintained database. Patients were operated and followed by a single surgeon. Outcome measures included wound complications and hernia recurrence. RESULTS: From 1996 until 2012, 41 patients (23 F, 18 M), with a mean age of 53.4 years and mean BMI of 31.2 ± 8 kg/m(2), were treated for chronic mesh infection (CMI). A suppurative infection was present in 27 patients, and 14 had an exposed mesh. The need for recurrent incisional hernia repair was observed in 25 patients; bowel resections or other potentially contaminated procedures were associated in 15 patients. The short-term results showed an uneventful post-operative course after mesh replacement in 27 patients; 6 (14.6%) patients developed a minor wound infection and were treated with dressings and antibiotics; 5 (12%) patients had wound infections requiring debridement and one required complete mesh removal. On the long-term follow-up, there were three hernia recurrences, one of which demanded a reoperation for enterocutaneous fistula; 95% of the patients submitted to mesh replacement were considered cured of CMI after a mean follow-up of 74 months. CONCLUSIONS: CMI can be treated by removal of infected mesh; simultaneous mesh replacement prevents hernia recurrence and has an acceptable incidence of post-operative acute infection. Standard polypropylene mesh is a suitable material to be used in the infected surgical field as an onlay graft.

Mesh cancer: long-term mesh infection leading to squamous-cell carcinoma of the abdominal wall.

PURPOSE: It is recognized that chronic inflammation can cause cancer. Even though most of the available synthetic meshes are considered non-carcinogenic, the inflammatory response to an infected mesh plays a constant aggression to the skin. Chronic mesh infection is frequently the result of misuse of mesh, and due to the challenging nature of this condition, patients usually suffer for years until the infected mesh is removed by surgical excision. METHODS: We report two cases of squamous-cell carcinoma (SCC) of the abdominal wall, arising in patients with long-term mesh infection. RESULTS: In both patients, the degeneration of mesh infection into SCC was presumably caused by the long-term inflammation secondary to infection. Patients presented with advanced SCC behaving just like the Marjolin's ulcers of burns. Radical surgical excision was the treatment of choice. The involvement of the bowel played an additional challenge in case 1, but it was possible to resect the tumor and the involved bowel and reconstruct the abdominal wall using polypropylene mesh as onlay reinforcement, in a single stage operation. He is now under adjuvant chemotherapy. The big gap in the midline after tumor resection in case 2 required mesh bridging to close the defect. The poor prognosis of case 2 who died months after the operation, and the involvement of the armpit, groin and mesenteric nodes in case 1 shows how aggressive this disease can be. CONCLUSION: Infected mesh must be treated early, by complete excision of the mesh. Long-standing mesh infection can degenerate into aggressive squamous-cell carcinoma of the skin.

Prosthetic repair of incisional hernia in kidney transplant patients. A technique with onlay polypropylene mesh.

The employment of synthetic mesh for incisional hernia repair in kidney-transplanted patients is rarely reported in the present literature. Many authors believe that mesh employment in such conditions is not safe due to fear of mesh related complications. From 1965 through 1999, a total of 1685 kidney transplants were performed at our Kidney Transplant Unit and 19 patients developed eventrations in the kidney transplant incision, an incidence of 1.1%. From September 1996 eight of these patients had prosthetic repair of the abdominal wall with onlay polypropylene mesh. All patients were under immunosuppressive therapy with prednisone, ciclosporine and azathioprine. Mean age was 48.8 years, mean body mass index was 22.5 and mean number of previous abdominal operations was 2.5. A large polypropylene mesh (Marlex mesh) was fixed over the aponeurosis after primary closure of the aponeurotic borders, as an onlay graft. There was neither morbidity nor mortality associated to the surgical procedure. No recurrences or long-term complications associated with mesh employment were verified after a follow-up ranging from one year to three years. We concluded that prosthetic repair of incisional hernia in transplanted patients can be performed routinely.

Elective colonic operation and prosthetic repair of incisional hernia: does contamination contraindicate abdominal wall prosthesis use?

BACKGROUND: Wound infection and sepsis leading to incisional hernia development are common after emergency colonic operations. Later on, while being operated on to correct an incisional hernia, most of these patients will need colonic resection or bowel continuity reestablishment. Simultaneous treatment of incisional hernias in patients with colostomy or colonic disease remains a difficult challenge, considering the reluctance of most surgeons to treat both conditions at the same time, especially when prosthetic repair is needed. STUDY DESIGN: The aim of this study was to analyze the short-term results of patients undergoing colonic resection or bowel continuity reestablishment and simultaneous incisional hernia repair with an onlay polypropylene mesh technique. Over a period of 6 years, 20 patients were operated on for colonic problems associated with incisional hernias, including 8 Hartmanns' colostomies, 6 colostomies or ileostomies with colonic mucous fistulas, 3 postoperative colocutaneous fistulas, a paracolostomic hernia, a Chagas' megacolon, and a pseudotumoral diverticulitis. A "rule of three" statistical analysis was used to estimate the maximum risk of adverse effects, concerning mesh-related morbidity, after 1- and 2-year followup. RESULTS: A major complication occurred in a patient who developed an anastomotic leakage and secondary wound infection; the patient was treated with parenteral nutrition and antibiotics. Other complications included a minor wound infection, a seroma, and a chronic sinus. One patient died from postoperative problems unrelated to the surgical technique. The occurrence of postoperative wound infection did not prevent mesh incorporation. Followup ranging from 1 to 7 years detected no hernia recurrences; 13 patients were followed for 2 years or more. Our results suggest that risk of mesh-related morbidity does not exceed 15.8% (3 of 19) within the first year and 23.1% (3 of 13) for 2 years followup, with 95% confidence. CONCLUSIONS: We concluded that prosthetic repair of incisional hernias associated with simultaneous colonic operations was possible, allowing abdominal wall anatomy reestablishment. There is no reason to believe that abdominal wall prostheses must be avoided in contaminated operations when an adequate surgical technique is used.