Management and outcome of mesh infection after abdominal wall reconstruction in a tertiary care center

Reconstruction of abdominal wall defect can be challenging, especially in comorbid patients and/or with complex hernias, following multiple surgeries or abdominal trauma. The final strategy must be safe and effective, and the use of mesh is now one of the most widely-performed surgical procedures [1, 2]. Post-operative infection represents a notable complication, with reported incidences ranging from 0.3% in clean inguinal hernia repairs to as high as 19.6% in complicated hernia cases [3, 4]. Such infections can lead to severe consequences, including sepsis, need for subsequent surgeries, development of chronic fistulas, persistent pain, or hernia recurrence [5]. Determinants of post-operative mesh infection have been extensively documented in existing literature [3, 6, 7]. They include mainly patient- and surgery-related parameters, such as age, body mass index (BMI), smoking status, length of surgery, open surgery compared with laparoscopic procedures, and hernia localization.

Various management strategies have been described [8‐10], involving the following interventions, alone or in combination: systemic antibiotic therapy, percutaneous drainage, complete or partial mesh removal, and negative pressure therapy [11]. However, these strategies have been poorly investigated, and criteria guiding clinicians in the selection of the most appropriate therapeutic approach are not available [12].

The objective of this study is to provide a comprehensive account of the clinical and microbiologic aspects of mesh infection observed in our tertiary care hospital, while describing treatment modalities employed and associated outcomes.

Our study represents one of the largest series examining characteristics, management strategies and outcome determinants of abdominal wall mesh infection [6, 8, 14]. However, some limitations must be acknowledged. First, the retrospective monocentric design of our study introduces inherent biases. Our tertiary care center tends to handle more complex cases with greater comorbidity and surgical complexity, potentially influencing treatment outcomes. Nevertheless, the diversity of practices across the four different visceral surgery wards within our center provides a comprehensive perspective. Notably, results from the subgroup analysis of patients not referred to our center (HCL group) were consistent with those of the total population, mitigating concerns regarding referral bias. A key limitation stems from the retrospective nature of patient recruitment, relying on keyword searches within medical records. This method may have overlooked minor wound events deemed insignificant by surgeons, resulting in underreporting of less severe infections such as inflammatory wound dehiscence. Consequently, our conclusions may not be generalized to cases presenting solely as wound dehiscence. Also, because of the retrospective design and the clinical definition of infection, it is difficult to state whether patients experiencing a complex healing course of the surgical wounds and who did not undergo subsequent surgical procedures had actually an infection involving the mesh. This doubt is in line with the observation that 24/146 (16.4%) patients were cured without local treatment only (i.e., wound care), arguing that they might have experienced a superficial surgical site infection or a wound hazard, but no deep infection. However, we decided to keep them in our analysis because they were considered as suspect of mesh infection by the treating team. Future works using a prospective design and standardized approach of wound management after abdominal wall repair could address this question. Nonetheless, our study offers valuable insights into the management and predictive factors for treatment success in more challenging presentations, such as abscesses and fistulas.

Microbiological analysis provided precise data, mostly consistent with the literature although the rate of S. aureus infections (36.1%) appeared lower than usually described (46–66%) [8, 14‐16], but higher than in a recent French cohort from another tertiary care center (23%) [17]. Our findings regarding microbial distribution according to infection depth revealed a gradient in bacterial types, reflecting distinct pathophysiological mechanisms between deep infections where gut commensal bacteria are prevailing, and superficial infections where skin commensal bacteria are predominant. Regarding empiric antibiotic treatment, combinations of amoxicillin plus clavulanate, or cefotaxime plus metronidazole, represent good options as they offer coverage regarding most strains of S. aureus, Enterobacteriaceae, and streptococci. Empiric use of broad-spectrum antimicrobials is not warranted in our setting. While differences in bacterial distribution were observed, it seems appropriate to use the same antibiotics for these different infection locations and types. Finally, pre-surgical pneumoperitoneum was associated with higher occurrence of MDR bacterial infection. As this technic is usually proposed for the most complicated abdominal wall repairs, pre-surgical invasive procedure and prolonged hospital stay in more comorbid patients might facilitate surgical site colonization and infection by nosocomial flora.

Management of hernia mesh infection is not codified and remains challenging, as evidenced by the 30.1% treatment failure rate in our study. This rate is congruent with 32.5% (39/120) patients presenting an infection after treatment in the cohort of Zou et al. [8]. Our study confirms the crucial impact of complete mesh removal for infection resolution, while partial mesh removal showed no significant impact on outcomes. Antibiotic therapy appears to be the second cornerstone of hernia mesh infection management.

In cases where complete surgical removal poses significant risks or challenges, conservative treatment may be considered. However, success rate appears to be lower, particularly in patients with chronic infection (symptom duration > 1 month), non-retromuscular mesh placement, and a history of multiple surgeries. These factors exerted a cumulative effect on treatment success, underscoring the importance of careful patient selection and stratification before adopting a conservative strategy.

While previous studies have highlighted certain predictors of treatment outcomes in conservative strategies, such as the early onset of infection [18], this finding regarding symptom duration as a prognostic factor is original. The association between symptom duration and treatment failure aligns with biofilm-related complications observed in orthopedic prosthetic material infections and the existing proof regarding biofilm development on hernia mesh [19, 20].

In conclusion, hernia mesh infection management remains challenging with high risk of treatment failure. The strategy of combining complete mesh removal with antibiotic therapy is the most promising approach for achieving successful outcomes. When conservative treatment is being considered, the physician must evaluate symptom duration and mesh placement, as the association of symptom duration > 1 month with non retromuscular located mesh in a multi operated abdomen is associated with > 75% failure risk.