History of methicillin-resistant Staphylococcus aureus (MRSA) surgical site infection may not be a contraindication to ventral hernia repair with synthetic mesh: a preliminary report

Favourable outcomes after Retro-Rectus (Rives-Stoppa) Mesh Repair as Treatment for Non-Complex Ventral Abdominal Wall Hernia, a Systematic Review and Meta-Analysis

OBJECTIVE

To assess prevalence of hernia recurrence, surgical site infection (SSI), seroma, serious complications, and mortality after retro-rectus repair.

SUMMARY BACKGROUND DATA

Ventral abdominal wall hernia is a common problem, tied to increasing frailty and obesity of patients undergoing surgery. For non-complex ventral hernia, retro-rectus (Rives-Stoppa) repair is considered the gold standard treatment. Level-1 evidence confirming this presumed superiority is lacking.

METHODS

Five databases were searched for studies reporting on retro-rectus repair. Single-armed and comparative randomized and non-randomized studies were included. Outcomes were pooled with mixed-effects, inverse variance or random-effects models.

RESULTS

Ninety-three studies representing 12440 patients undergoing retro-rectus repair were included. Pooled hernia recurrence was estimated at 3.2% (95%CI: 2.2-4.2%, n = 11049) after minimally 12 months and 4.1%, (95%CI: 2.9-5.5%, n = 3830) after minimally 24 months. Incidences of SSI and seroma were estimated at respectively 5.2% (95%CI: 4.2-6.4%, n = 4891) and 5.5% (95%CI: 4.4-6.8%, n = 3650). Retro-rectus repair was associated with lower recurrence rates compared to onlay repair (OR: 0.27, 95%CI: 0.15-0.51, p < 0.001) and equal recurrence rates compared to intraperitoneal onlay (IPOM) repair (OR: 0.92, 95%CI: 0.75-1.12, p = 0.400). Retro-rectus repair was associated with more SSI than IPOM repair (OR: 1.8, 95%CI: 1.03-3.14, p = 0.038). Minimally invasive retro-rectus repair displayed low rates of recurrence (1.3%, 95%CI: 0.7-2.3%, n = 849) and SSI (1.5%, 95%CI: 0.8-2.8%, n = 982), albeit based on non-randomized studies.

CONCLUSIONS

Retro-rectus (Rives-Stoppa) repair results in excellent outcomes, superior or similar to other techniques for all outcomes except surgical site infection. The latter rarely occurred, yet less frequently after IPOM repair, which is usually performed by laparoscopy.

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.

Postoperative Prophylactic Antibiotics Reduce Surgical Site Infection Rates after Ventral Hernia Repair: A Systematic Review

SSIs after ventral hernia repair (VHR) represent a significant complication. The impact of postoperative prophylactic antibiotics on the SSI rates after VHRs is unclear. A systematic review of PubMed and Web of Science databases from inception through March 2016 investigating the effect of postoperative prophylactic antibiotics after VHRs was performed. Strict inclusion and exclusion criteria were implemented, and the methodological quality of the included studies was assessed. After systematic independent assessment of 216 citations, four studies, involving 344 patients, met the inclusion criteria. Among the included studies, 164 patients received >24 hours of postoperative prophylactic antibiotics, whereas 180 patients were controls. The overall incidence of SSI among patients receiving postoperative antibiotics was 14.6 per cent (95% confidence interval [CI], 9.9 to 20.9) which compares favorably with the control group: 35.5 per cent (95% CI, 28.9 to 42.7) (odds ratio: 0.3, 95% CI: 0.2 to 0.5, P < 0.01). Among patient's receiving postoperative antibiotics, the pooled average duration of postoperative antibiotic treatment was 6.2 ± 0.4 days. Based on the available evidence, the use of postoperative prophylactic antibiotics seems to be associated with lower SSI rates after VHRs. Future prospective randomized controlled trials should be conducted to further confirm the efficacy of this prophylactic intervention.

Methicillin-resistant Staphylococcus aureus (MRSA): antibiotic-resistance and the biofilm phenotype

Staphylococcus aureus (S. aureus) is an asymptomatic colonizer of 30% of all human beings. While generally benign, antibiotic resistance contributes to the success of S. aureus as a human pathogen. Resistance is rapidly evolved through a wide portfolio of mechanisms including horizontal gene transfer and chromosomal mutation. In addition to traditional resistance mechanisms, a special feature of S. aureus pathogenesis is its ability to survive on both biotic and abiotic surfaces in the biofilm state. Due to this characteristic, S. aureus is a leading cause of human infection. Methicillin-resistant S. aureus (MRSA) in particular has emerged as a widespread cause of both community- and hospital-acquired infections. Currently, MRSA is responsible for 10-fold more infections than all multi-drug resistant (MDR) Gram-negative pathogens combined. Recently, MRSA was classified by the World Health Organization (WHO) as one of twelve priority pathogens that threaten human health. In this targeted mini-review, we discuss MRSA biofilm production, the relationship of biofilm production to antibiotic resistance, and front-line techniques to defeat the biofilm-resistance system.

Surgical site infection: the "Achilles Heel" of all types of abdominal wall hernia reconstruction

PURPOSE

Surgical site infection is the most common hospital-acquired infection in surgical patients. Recently, public health organizations have updated prevention guidelines. This review discusses surgical site infections as a complication of abdominal wall reconstruction.

METHODS

The authors reviewed guidelines on prevention of surgical site infections from the Center for Disease Control and Prevention, World Health Organization, and National Institute for Health and Care Excellence and put them into context with the relevant abdominal wall reconstruction literature. This was the subject of the Nyhus-Wantz lecture given at The International Hernia Congress on March 14, 2018 in Miami, FL and is summarized here.

RESULTS

Routine use of preoperative antibiotics in prosthetic groin hernia repair is not supported by the available literature. High-quality data on antibiotic prophylaxis in ventral (both primary and incisional) hernia repair is lacking, but it is widely utilized and may reduce SSIs. Recommended preventative strategies discussed in this manuscript include: treatment of remote site infections, perioperative normothermia and normoglycemia, avoidance of hypoxemia, antiseptic preparation of surgical team hands and patient skin, treatment of obesity, smoking cessation, correction of malnutrition, and physical conditioning.

CONCLUSION

Surgical site infections lead to significant morbidity and mortality, hernia recurrences, prolonged hospital stay, and increased hospital costs. This makes surgical site infections the "Achilles Heel" of abdominal wall reconstruction. Strict adherence to standardized guidelines and preoperative optimization of patients' risk profiles are crucial to decrease the incidence of surgical site infections.

Infection prevention using affinity polymer-coated, synthetic meshes in a pig hernia model

BACKGROUND

Given concern for hernia mesh infection, surgeons often use biologic mesh which may provide reduced risk of infection but at the cost of decreased repair durability. We evaluated mesh coating to provide sustained release of antibiotics to prevent prosthetic mesh infection and also allow a durable repair.

MATERIALS AND METHODS

Cyclodextrin-based polymer was crosslinked onto multifilament polyester mesh and loaded with vancomycin (1.75 mg/cm²). Pigs received modified meshes (n = 6) or normal, untreated meshes (n = 4), which were implanted into acute 10 × 5 cm ventral hernia, then directly inoculated with 10⁶ colony-forming unit (CFU) of methicillin-resistant Staphylococcus aureus (MRSA). These were compared to animals receiving normal, uninfected mesh. All mesh was secured in an underlay bridge manner, and after 30 d, the abdominal wall was removed for quantitative bacterial culture and biomechanical analysis.

RESULTS

All animals survived 30 d. All six animals with coated mesh cleared MRSA infection. The four control animals did not clear MRSA (P = 0.005). Quantitative bacterial load was higher in standard mesh versus drug-delivery mesh group (2.34 × 10⁴versus 80.9 CFU/gm). These data were log₁₀-transformed and analyzed by Welch's t-test (P = 0.001). Minimum number of CFUs detectable by assay (300) was used instead of zero. Biomechanical analysis of controls (1.82 N/mm infected; 1.71 N/mm uninfected) showed no difference to the modified meshes (1.31 N/mm) in tissue integration (P = 0.15).

CONCLUSIONS

We successfully prevented synthetic mesh infection in a pig model using a cyclodextrin-based polymer to locally deliver vancomycin to the hernia repair site and clearing antibiotic-resistant bacteria. Polymer coating did not impact the strength of the hernia repair.

Active Staphylococcus aureus infection: Is it a contra-indication to the repair of complex hernias with synthetic mesh? A prospective observational study on the outcomes of synthetic mesh replacement, in patients with chronic mesh infection caused by Staphylococcus aureus

INTRODUCTION

The management of chronic mesh infection is challenging and controversial. The use of synthetic material to repair the abdominal wall in the infected setting is not recommended, especially in the presence of active infection caused by Staphylococcus aureus.

METHODS

This is a prospective observational study designed to evaluate the outcomes in patients with active mesh infection caused by Staphylococcus aureus. Patients underwent simultaneous removal and replacement of polypropylene mesh. The treatment protocol included the complete removal of infected mesh, followed by the anatomical reconstruction, and reinforcement of the abdominal wall using a new onlay polypropylene mesh. Early and late wound complications, medical complications, and hernia recurrences were analyzed.

RESULTS

From 2006 until 2014, 22 patients with a mean age of 57.2 years and mean BMI of 29,3 kg/m2 were studied. Sinuses were present in 21 patients. A recurrent ventral hernia was observed in 14 patients; two patients required a complex abdominal wall reconstruction due to enteric fistulas. Bowel resections or other potentially contaminated procedures were associated in 10 patients. Fourteen patients (63.6%) had an uneventful postoperative course; 5 (22.7%) patients had wound infections requiring debridement and three required partial (2) or total (1) mesh removal. Two patients died due to medical complications. Adverse results on long-term follow-up included one hernia recurrence after complete mesh removal and one persistent sinus after partial mesh removal requiring a reoperation to remove mesh remnants. All of the patients were considered free of infection after a mean follow-up of 44 months.

CONCLUSIONS

Synthetic mesh replacement in patients with active Staphylococcus aureus infection has an acceptable incidence of postoperative wound infection and prevents hernia recurrence. Large-pore polypropylene mesh is a suitable material to be used in the infected surgical field as an onlay graft.

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.