Resistance of Synthetic and Biologic Surgical Meshes to Methicillin-Resistant Staphylococcus aureus Biofilm: An In Vitro Investigation

The Great Debate: Mesh or No Mesh in Contaminated Hernia Repairs?

Abdominal hernia surgeries are commonly performed with many different approaches, and mesh utilization has become a cornerstone in hernia repair, ensuring durable outcomes with minimal recurrence risk. However, managing contaminated hernia repairs presents unique challenges due to the heightened risks of mesh infection. Recent advancements in lightweight macroporous polypropylene meshes offer promising solutions. Studies have highlighted the superiority of macroporous polypropylene meshes compared to primary suture repair and other mesh types in terms of reduced surgical site infection rates and lower hernia recurrence rates. Moreover, utilizing macroporous polypropylene mesh in the retrorectus plane is associated with a favorable salvage rate, underscoring its efficacy in contaminated hernia repairs. At the same time, contrary evidence suggests higher postoperative complications with mesh use in settings of clean-contaminated or contaminated fields. Most significant complications are increased infection rates and similar recurrence rates compared to mesh-free repairs. New synthetic mesh that is being marketed as having better outcomes than other types of mesh and potentially primary repair need to be carefully assessed as biologic mesh once used to also be touted as the mesh to use in such fields, but more research is showing higher complication rates. The risk of infection and consequent morbidity might outweigh the benefit of less recurrence risk with mesh use. Further research, including prospective studies with long-term follow-up, is warranted to elucidate optimal hernia repair strategies in contaminated fields and inform evidence-based practice guidelines.

The Effects of Pectin-Honey Hydrogel in a Contaminated Chronic Hernia Model in Rats

Incisional hernia is a frequent complication after abdominal surgery. A previous study on rats evaluated the use of a Pectin-Honey Hydrogel (PHH)-coated polypropylene (PP) mesh for the healing of acute hernias. However, there are no studies investigating the use of PHH in association with PP mesh in chronic contaminated hernia. The aims of this study are to assess the effectiveness of PHH in promoting abdominal hernia repaired with PP mesh and in counteracting infection. Twenty Sprague Dawley male rats were enrolled and a full thickness defect was made in the abdominal wall. The defect was repaired after 28 days using a PP mesh, and a culture medium (Tryptone Soy Broth, Oxoid) was spread onto the mesh to contaminate wounds in both groups. The rats were randomly assigned to a treated or untreated group. In the treated group, a PHH was applied on the mesh before skin closure. At euthanasia-14 days after surgery-macroscopical, microbiological and histopathological evaluations were performed, with a score attributed for signs of inflammation. An immunohistochemical investigation against COX-2 was also performed. Adhesions were more severe (p = 0.0014) and extended (p = 0.0021) in the untreated group. Bacteriological results were not significantly different between groups. Both groups showed moderate to severe values (score > 2) in terms of reparative and inflammatory reactions at histopathological levels. The use of PHH in association with PP mesh could reduce adhesion formation, extension and severity compared to PP mesh alone. No differences in terms of wound healing, contamination and grade of inflammation were reported between groups.

Risks and Prevention of Surgical Site Infection After Hernia Mesh Repair and the Predictive Utility of ACS-NSQIP

AIM

The aim of this paper was to provide a narrative review of surgical site infection after hernia surgery and the influence of perioperative preventative interventions.

METHODS

The review was based on current national and international guidelines and a literature search.

RESULTS

Mesh infection is a highly morbid complication after hernia surgery, and is associated with hospital re-admission, increased health care costs, re-operation, hernia recurrence, impaired quality of life and plaintiff litigation. The American College of Surgeons National Surgical Quality Improvement Program is a particularly useful resource for the study and evidence-based practise of abdominal wall hernia repair.

DISCUSSION

The three major modifiable patient comorbidities significantly associated with postoperative surgical site infection in hernia surgery are obesity, tobacco smoking and diabetes mellitus. Preoperative optimization includes weight loss, cessation of smoking, and control of diabetes. Intraoperative interventions relate, in particular, to the control of fomite mediated transmission in the operating theatre and prevention of mesh contamination with S. aureus CFUs. Risk management strategies should also target the niche ecological conditions which enable bacterial survival and subsequent biofilm formation on an implanted mesh. Outcomes of mesh infection after hernia surgery are closely related to mesh type and porosity, patient smoking status, presence of MRSA, bacterial adhesion and biofilm production. The use of suction drains and the timing of drain removal are controversial and discussed in detail. Finally, the utility of the ACS-NSQIP Surgical Risk Calculator in predicting complications and outcomes in individual patients and the importance of quality improvement initiatives in surgical units are emphasized.