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.

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 computerized tomography scan method for calculating the hernia sac and abdominal cavity volume in complex large incisional hernia with loss of domain.

Preoperative progressive pneumoperitoneum (PPP) is a safe and effective procedure in the treatment of large incisional hernia (size > 10 cm in width or length) with loss of domain (LIHLD). There is no consensus in the literature on the amount of gas that must be insufflated in a PPP program or even how long it should be maintained. We describe a technique for calculating the hernia sac volume (HSV) and abdominal cavity volume (ACV) based on abdominal computerized tomography (ACT) scanning that eliminates the need for subjective criteria for inclusion in a PPP program and shows the amount of gas that must be insufflated into the abdominal cavity in the PPP program. Our technique is indicated for all patients with large or recurrent incisional hernias evaluated by a senior surgeon with suspected LIHLD. We reviewed our experience from 2001 to 2008 of 23 consecutive hernia surgical procedures of LIHLD undergoing preoperative evaluation with CT scanning and PPP. An ACT was required in all patients with suspected LIHLD in order to determine HSV and ACV. The PPP was performed only if the volume ratio HSV/ACV (VR = HSV/ACV) was >or=25% (VR >or= 25%). We have performed this procedure on 23 patients, with a mean age of 55.6 years (range 31-83). There were 16 women and 7 men with an average age of 55.6 years (range 31-83), and a mean BMI of 38.5 kg/m(2) (range 23-55.2). Almost all patients (21 of 23 patients-91.30%) were overweight; 43.5% (10 patients) were severely obese (obese class III). The mean calculated volumes for ACV and HSV were 9,410 ml (range 6,060-19,230 ml) and 4,500 ml (range 1,850-6,600 ml), respectively. The PPP is performed by permanent catheter placed in a minor surgical procedure. The total amount of CO(2) insufflated ranged from 2,000 to 7,000 ml (mean 4,000 ml). Patients required a mean of 10 PPP sessions (range 4-18) to achieve the desired volume of gas (that is the same volume that was calculated for the hernia sac). Since PPP sessions were performed once a day, 4-18 days were needed for preoperative preparation with PPP. The mean VR was 36% (ranged from 26 to 73%). We conclude that ACT provides objective data for volume calculation of both hernia sac and abdominal cavity and also for estimation of the volume of gas that should be insufflated into the abdominal cavity in PPP.