Infections associated with prosthetic repairs of abdominal wall hernias: pathology, management and results

Mesh repair versus non-mesh repair for incarcerated and strangulated groin hernia: an updated systematic review and meta-analysis

BACKGROUND

Mesh repair in incarcerated or strangulated groin hernia is controversial, especially when bowel resection is required. We aimed to perform a meta-analysis comparing mesh and non-mesh repair in patients undergoing emergency groin hernia repair.

METHODS

We performed a literature search of databases to identify studies comparing mesh and primary suture repair of patients with incarcerated or strangulated inguinal or femoral hernias who underwent emergency surgery. Postoperative outcomes were assessed by pooled analysis and meta-analysis. Statistical analysis was performed using RevMan 5.4. Heterogeneity was assessed with I2 statistics.

RESULTS

1095 studies were screened and 101 were thoroughly reviewed. Twenty observational studies and four randomized controlled trials comprising 12,402 patients were included. We found that mesh-based repair had reduced recurrence (OR 0.36; 95% CI 0.19, 0.67; P = 0.001; I2 = 35%), length of hospital stay (OR - 1.02; 95% CI - 1.87, - 0.17; P = 0.02; I2 = 94%) and operative time (OR - 9.21; 95% CI - 16.82, - 1.61; P = 0.02; I2 = 95%) without increasing surgical site infection, mortality or postoperative complications such as seroma, chronic, ileus or urinary retention. In the subgroup analysis of patients that underwent bowel resection, we found that mesh repair was associated with an increased risk of surgical site infection (OR 1.74; 95% CI 1.04, 2.91; P = 0.04; I2 = 9%).

CONCLUSIONS

Mesh repair for incarcerated and strangulated groin hernias reduces recurrence without an increase in postoperative complications and should be considered in clean cases. However, in the setting of bowel resection, mesh repair might increase the incidence of surgical site infection.

Complete Versus Partial Excision of an Infected Mesh Following Abdominal Wall Hernia Repair: A Systematic Review and Meta-analysis

BACKGROUND

To evaluate comparative outcomes of complete and partial excision of infected mesh following abdominal wall hernia repair.

METHODS

A systematic search of electronic databases, including MEDLINE, EMBASE, CINAHL, and CENTRAL, and bibliographic reference lists with application of a combination of free text and controlled vocabulary search adapted to thesaurus headings, search operators and limits was conducted. Surgical site infection chronic sinus formation, recurrent hernia, and need for reoperation were the evaluated outcome measures.

RESULTS

Six comparative observational studies were identified, reporting a total of 317 patients of whom 193 underwent complete mesh excision and the remaining 123 patients underwent partial mesh excision for an infected mesh following abdominal wall hernia repair. The complete mesh excision was associated with significantly lower rates of SSIs (OR: .36; 95% CI, .16-.81, P = .01), chronic sinus formation (OR: .11; 95% CI, .02-.71, P = .02), and reoperation (OR: .10; 95% CI, .03-.33, P = .0001) compared to the partial mesh excision. There was no significant difference in hernia recurrence rate (OR: 3.96.16, 95% CI .62-25.44, P = .15) between two groups. The between-study heterogeneity was moderate in all the analyses.

CONCLUSIONS

Complete mesh excision may be associated with lower SSI, chronic sinus formation and need for reoperation when compared to the partial mesh excision in an infected mesh event. However, the available evidence has failed to report the outcomes with respect to the main confounding factors which, together with other important outcomes such as fistula formation, should be considered by future high quality research.

Hernia Mesh Complications: Management of Mesh Infections and Enteroprosthetic Fistula

The potential consequences of mesh infection mandate careful consideration of surgical approach, mesh selection, and preoperative patient optimization when planning for ventral hernia repair. Intraperitoneal mesh, microporous or laminar mesh, and multifilament mesh typically require explantation, whereas macroporous, monofilament mesh in an extraperitoneal position is often salvageable. Delayed presentation of mesh infection should raise the suspicion for enteroprosthetic fistula when intraperitoneal mesh is present. When mesh excision is necessary, the surgeon must carefully consider both the risk of recurrent infection as well as hernia recurrence when deciding on single-stage definitive reconstruction versus primary closure with delayed reconstruction.

Value of CT sinography and analysis of missed diagnosis and misdiagnosis for abdominal wall sinus

Background

The value of CT (computed tomography) sinography in evaluating abdominal wall sinus tracts is currently unclear. The present study aims to investigate the accuracy of CT sinography in diagnosing the extent of abdominal sinus and analyze the reasons for misdiagnosis.

Materials and methods

64 patients with abdominal sinus tract formation (including fistula) undergoing CT sinography in our hospital from January 2018 to November 2020 were retrospectively analyzed. The CT images were blindly and independently re-assessed by two radiologists with 5- and 18-years work experience, respectively. Whether the sinus tract was confined to the abdominal wall or had invaded the abdominal cavity, and whether there was fistula formation were evaluated. The accuracy of CT sinography in diagnosing sinus invasion in the abdominal cavity and fistula formation was calculated. The agreements of CT sinography-surgical results and inter-observer were assessed using weighted-kappa statistics.

Results

The weighted- Kappa of inter-observer agreement (0.825, P < 0.001) and CT sinography—surgical results (0.828, P < 0.001) were both perfect. The diagnostic accuracy, sensibility, and specificity of sinus tract confined to the abdominal wall were 90.6% (95% CI: 80.7–96.5), 85.7% (95% CI: 67.3–96.0), and 94.4% (95% CI: 81.3–99.3), respectively. The diagnostic accuracy, sensibility, and specificity of fistula formation were 93.8% (95% CI: 84.8–98.3), 89.5% (95% CI: 66.9–98.7), and 95.6% (95% CI: 84.9–99.5), respectively. A total of 4 cases of sinus tract confined to the abdominal wall were misdiagnosed as invading the abdominal cavity, 2 cases of sinus tract invading the abdominal cavity were misdiagnosed as confined to the abdominal wall, 2 cases of enterocutaneous fistula were missed, 1 case of enterocutaneous fistula was misdiagnosed, 1 case of vesico-cutaneous fistula was misdiagnosed, and no cases of vesico-cutaneous fistula were missed.

Conclusions

CT sinography can accurately assess the extent of an abdominal sinus tract and reveal fistula formation, despite some inevitable misdiagnosis and missed diagnosis. Radiologists should find more clues to improve the diagnostic accuracy.

Different etiopathogeneses in early-onset and late-onset inguinal hernia mesh infections in a prospectively evaluated cohort

INTRODUCTION

Inguinal hernia mesh infection (IHMI) is a rare but a significant problem. The aim of this study was to determine whether etiopathogeneses of early-onset and late-onset IHMIs differ in terms of the origin of infectious agents, and route of dissemination.

PATIENTS AND METHODS

This was a retrospective cohort study with prospective data collection of patients operated on from 2013 to 2015. Early-onset IHMI was defined as symptoms developed within one year after the index surgery, whereas late-onset IHMI was defined as infection developed later than a year after the index surgery. Age, gender, ASA score, BMI, time from index surgery, isolated infectious agents and possible pathogeneses were analyzed.

RESULTS

During the study period, 1438 patients underwent inguinal hernia repair. Sixteen patients (1.1%) had IHMI, of whom nine were early-onset and seven late-onset. The groups were comparable for age (p = .54), gender (p = 1.0), BMI (p = .79), and ASA score (p = 1.0). The most common infectious agent in early-onset IHMI was St. aureus, whereas Enterococci and Enterobacter prevailed in late-onset IHMI. The possible pathogenesis of IHMI in seven patients with early-onset IHMI was primary exogenous infection, whereas in patients with late-onset IHMI the pathogenesis might be hematogenous or contact spread. All patients with IHMI underwent mesh removal. In two patients (one from each group), partial mesh removal was performed previously and IHMI recurred.

CONCLUSIONS

Early-onset hernia mesh infection is mostly caused by St. aureus through exogenous contamination, whereas its late-onset counterpart might be a result of hematogenous or contact spread of intestinal flora.

Surgical management of infected abdominal wall mesh: an analysis using the American Hernia Society Quality Collaborative

INTRODUCTION

Several management strategies exist for the treatment of infected abdominal mesh. Using the American Hernia Society Quality Collaborative, we examined management patterns and 30-day outcomes of infected mesh removal with concomitant incisional hernia repair.

METHODS

All patients undergoing incisional hernia repair with removal of infected mesh were identified. A complete repair (CR) was defined as fascial closure with mesh; a partial repair (PR) was defined as fascial closure without mesh or no fascial closure with mesh. A two-tailed p value less than or equal to 0.05 was considered statistically significant.

RESULTS

A total of 282 patients were identified: 136 patients in CR group and 146 patients in PR group. Patients had similar comorbidities but differed in wound class (class IV: 55% CR vs 83% SR, p < 0.001) and incidence of associated concomitant colorectal procedures (5% CR vs 18% SR, p = 0.015). Sublay placement was used primarily in CR (94%) compared to PR (52% inlay, 48% sublay). When comparing CR to PR, length of stay (median 6, p = 0.69), complications (40% vs 44%, p = 0.44), surgical site infections (16% vs 21%, p = 0.27), surgical site occurrence (30% vs 35%, p = 0.45), and readmission within 30 days (9% vs. 13%) were not statistically different.

CONCLUSIONS

Analysis of data from a multicenter hernia registry comparing CR and PR during infected mesh removal and concurrent incisional hernia repair has not identified higher rates of short-term complications between groups in the presence of infection.

Comparison of Midterm Outcomes Between Open and Robotic Emergent Ventral Hernia Repair

Background. There are no studies on the role of robotics in emergency ventral hernia repair (EVHR). We aimed to compare outcomes of robotic EVHR (REVHR) and open (OEVHR). Methods. We performed a retrospective study of EVHRs performed between 2013 and 2019. Patients who underwent ventral hernia repair in an elective setting and patients who had concomitant non-abdominal wall procedures were excluded. Pre-, intra-, and postoperative variables were compared. Univariate and multivariate analyses were performed. Results. In all, 43 patients underwent OEVHR as compared to 35 patients who underwent REVHR. The patients in both groups were similar in terms of hernia etiology as well as Acute Physiology and Chronic Health Evaluation (APACHE-II) and the Sequential Organ Failure Assessment (SOFA) scores. Mean operative times for the robotic group were almost 2-fold compared with those of the open group (139 minutes vs 70 minutes, respectively; P < .001). Median length of stay (LOS) did not differ between the groups (3 days for both groups; P = .488). Major complications (P = .001), morbidity scores (P = .006), surgical site events (SSEs) (P = .045), and procedural interventions (P = .020) were found higher in the open group. No differences in freedom of recurrence were found (P = .662). Multivariate logistic regression analysis showed that open repair was associated with a 4-fold risk for the development of complications as compared to robotic repair (P = .025; odds ratio (OR) = 4, 95% confidence interval (CI) = 1.193-13.444). Conclusion. Compared to OEVHR, REVHR resulted in longer operative times and lower morbidity, including SSEs and related interventions. However, neither LOS nor recurrence differed between the groups.

Impact of Body Mass Index (BMI) on perioperative outcomes following minimally invasive retromuscular abdominal wall reconstruction: a comparative analysis

BACKGROUND

Morbidity and recurrence rates are higher in obese patients undergoing open abdominal wall reconstruction (AWR). Historically, body mass index (BMI) ≥ 40 has served as a relative contraindication to open AWR. The purpose of this study is to evaluate the impact of minimally invasive surgery (MIS) on outcomes after AWR for higher versus lower BMI patients.

METHODS

A retrospective review of a prospectively maintained database was conducted of all patients who underwent MIS AWR between September 2015 and April 2019 at our institution. Patients were subdivided into two groups based on their BMI: BMI ≤ 35 kg/m² and BMI > 35 kg/m². Patient demographics and perioperative data were evaluated using univariate and multivariate analysis.

RESULTS

461 patients were identified and divided into two groups: BMI ≤ 35 (n = 310) and BMI > 35 (n = 151). The two groups were similar in age (BMI ≤ 35: 56.3 ± 14.1 years vs. BMI > 35: 54.4 ± 11.9, p = .154). BMI > 35 group had more patients with ASA score of 3 (81% vs. 32%, p < .001) and comorbid conditions such as hypertension (70% vs. 45%, p < .001), diabetes mellitus (32% vs. 15%, p < .001), and history of recurrent abdominal wall hernia (34% vs. 23%, p = .008). BMI > 35 group underwent a robotic approach at higher rates (74% vs. 45%, p < .001). Patients who underwent a Rives-Stoppa repair from the higher BMI cohort also had a larger defect size (5.6 ± 2.4 cm vs. 6.7 ± 2.4 cm, p = .004). However, there were no differences in defect size in patients who underwent a transversus abdominus release (BMI ≤ 35: 9.7 ± 4.9 cm vs. BMI > 35: 11.1 ± 4.6 cm, p = .069). Both groups benefited similarly from a short length of stay, similar hospital charges, and lower postoperative complications.

CONCLUSION

Initial findings of our data support the benefits of elective MIS approach to AWR for patients with higher BMI. These patients derive similar benefits, such as faster recovery with low recurrence rates, when compared to lower BMI patients, while avoiding preoperative hernia incarceration, postoperative wound complications, and hernia recurrences. Future follow-up is required to establish long-term perioperative and quality of life outcomes in this patient cohort.

Costs and Complications Associated with Infected Mesh for Ventral Hernia Repair

Background: Mesh hernia repair is widely accepted because of the associated reduction in hernia recurrence compared with suture-based repair. Despite initiatives to reduce risk, mesh infection and mesh removal are a significant challenge. In an era of healthcare value, it is essential to understand the global cost of care, including the incidence and cost of complications. The purpose of this study was to identify the outcomes and costs of care of patients who required the removal of infected hernia mesh. Methods: A review of databases from 2006 through June 2018 identified patients who underwent both ventral hernia repair (VHR) and re-operation for infected mesh removal. Patient demographic and operative details for both procedures, including age, Body Mass Index, mesh type, amount of time between procedures, and information regarding interval procedures were obtained. Clinical outcome measures were the length of the hospital stay, hospital re-admission, incision/non-incision complications, and re-operation. Hospital cost data were obtained from the cost accounting system and were combined with the clinical data for a cost and clinical representation of the cases. Results: Thirty-four patients underwent both VHR and removal of infected mesh material over the 12-year time frame and were included in the analyses; the average age at VHR was 48 years, and 16 patients (47%) were female. Following VHR, 21 patients (62%) experienced incision complications within 90 days post-operatively, the complications ranging from superficial surgical site infection (SSI) to evisceration. A mean of 22.65 months passed between procedures. After mesh removal, 16 patients (47%) experienced further incisional complications; and 22 (65%) patients had at least one re-admission. Eighteen patients (53%) required a minimum of one additional related operative procedure after mesh removal. Median hospital costs nearly doubled (p < 0.001) for the mesh removal ($23,841 [interquartile range {IQR} $13,596-$42,148]) compared with the VHR admission ($13,394 [IQR $8,424-$22,161]) not accounting for re-admission costs. A majority experienced hernia recurrence subsequent to mesh removal. Conclusions: Mesh infection after hernia repair is associated with significant morbidity and costs. Hospital re-admission, re-operations, and recurrences are common among these patients, resulting in greater healthcare resource utilization. Development of strategies to prevent mesh infection, identify patients most likely to experience infectious complications, and define best practices for the care of patients with mesh infection are needed.

Deep SSI after mesh-mediated groin hernia repair: management and outcome in an Emergency Surgery Department

AIM

Mesh-mediated groin hernia repair is considered the goldstandard procedure. It has low recurrence rate. Rarely a deep Surgical Site Infection (SSI) is seen when a synthetic prosthesis is used.

CASE REPORT

We describe a rare case of bilateral deep SSI after mesh-mediated groin hernia repair. Diagnosis was performed through the physical examination and radiological exams. Microbiological samples identified a methicillin-resistant Staphylococcus aureus responsible of the infection. Target therapy was performed and re-operation performed in order to remove the infected prosthesis and to apply a biological one to create the fibrous scaffold. During follow-up time, right side recurrence was observed. Tru-cut biopsy of fascia was obtained in order to identify the responsible of the recurrence.

CONCLUSION

Combination of antibiotic therapy and surgical reoperation seems to be the correct way to approach the deep SSI after mesh-mediated groin hernia repair. The use of biological mesh after synthetic removal seems to improve the final outcome.

Study of mesh infection management following inguinal hernioplasty with an analysis of risk factors: a 10-year experience

PURPOSE

We present a review of our 10-year experience in managing patients with mesh infection following hernioplasty and analyze the occurrence of known predisposing factors.

METHODS

We analyzed 392 cases of mesh infection treated at our center between 2007 and 2018 after a preoperative work-up. (Thirty-one patients underwent the primary hernia repair procedure at our hospital, whereas the others underwent the primary surgery at other local centers and were referred to our center.) The method of infected mesh removal (open or laparoscopic) was selected depending on the primary surgical approach. Open repair involved the excision of the mesh, infected tissue, and sinus (if present). The laparoscopic approach was used to identify the abscess, excise the mesh, and allow drainage into the preperitoneal space.

RESULTS

The operative course in all patients was uneventful. A second surgery to extract the residual mesh around the pubic bone was performed in 7 patients. Hernia recurred in 29 patients after mesh removal. The discharge culture results were positive in 193 patients. Of these, Staphylococcus spp. was identified as the causative organism in 126 patients. Risk factors for mesh infection, including obesity, smoking, and diabetes, were identified in 182 (46.5%), 154 (39.3%), and 35 (8.9%) patients, respectively.

CONCLUSIONS

It is recommended the approach of mesh removal is tailored as per the primary hernioplasty method. We analyzed the occurrence of risk factors for mesh infection in this study, but further studies are needed to develop a predictive model that is both internally and externally validated to evaluate the probability of mesh infection.

Complex abdominal wall hernias as a barrier to quality of life in cancer survivors

Background

Many cancer survivors live with postoperative complex abdominal wall hernias (CAWHs). However, the impact of CAWHs on their quality of life is unknown, and few descriptions of patient experiences exist. We performed a qualitative study to explore cancer survivors’ experience with CAWHs before and after repair.

Methods

Patients waiting to undergo CAWH repair or who had completed the surgery in the previous 18 months were identified from a single surgeon’s practice in CAWH at a tertiary care centre. Clinical and demographic data were extracted from the electronic patient record. An in-depth semistructured interview guide was developed by experts in CAWH and qualitative methodology. Interviews were conducted in March 2013. We used comparative analysis techniques and coding strategies to identify themes.

Results

Ten preoperative and 12 postoperative participants were interviewed. The average age of the participants was 64 years in both groups, with an even sex distribution. The most frequently diagnosed cancer in both groups was colorectal cancer. Participants’ views were organized into 5 themes: 1) unable to return to normal life, 2) sense of abandonment, 3) experiencing fear and distress, 4) preoperative: desperate for help and 5) postoperative: “getting my life back.”

Conclusion

Our findings show the all-encompassing impact of a CAWH on the life of cancer survivors. They strongly suggest that hernia management should be viewed as an integral part in the continuum of cancer treatment to improve the quality of life of cancer survivors with hernias.

Management of Infected Mesh After Abdominal Hernia Repair: Systematic Review and Single-Institution Experience

BACKGROUND

Mesh infection after abdominal hernia repair is a devastating complication that affects general and plastic surgeons alike. The purpose of this study was 3-fold: (1) to determine current evidence for treatment of infected abdominal wall mesh via systematic review of literature, (2) to analyze our single-institution experience with treatment of infected mesh patients, and (3) to establish a framework for how to approach this complex clinical problem.

METHODS

Literature search was performed using the Preferred Reporting Items for Systematic Reviews and Meta-analysis guidelines, followed by single-institution retrospective analysis of infected mesh patients.

RESULTS

A total of 3565 abstracts and 92 full-text articles were reviewed. For qualitative and quantitative assessment, articles were subdivided on the basis of treatment approach: "conservative management," "excision of mesh with primary closure," "single-stage reconstruction," "immediate staged repair," and "repair in contaminated field." Evidence for each treatment approach is presented. At our institution, most patients (40/43) were treated by excision of infected mesh and single-stage reconstruction with biologic mesh. When the mesh was placed in a retrorectus or underlay fashion, 21.4% rate of hernia recurrence was achieved. Bridged repairs were highly prone to recurrence (88.9%; P = 0.001), but the bridging biologic mesh seemed to maintain domain and potentially contribute to a more effective repair in the future. Of the patients who underwent additional ("secondary") repairs after recurrence, 75% were eventually able to achieve "hernia-free" state.

CONCLUSIONS

This study reviews the literature and our single-institution experience regarding treatment of infected abdominal wall mesh. Framework is developed for how to approach this complex clinical problem.

Combined single-stage enterolysis with pedicle seromuscular bowel flaps, myocutaneous and fasciocutaneous flaps to repair recurrent enterocutaneous fistulas in complex abdominal Wall defects

INTRODUCTION

Reconstruction of abdominal wall defects with enterocutaneous fistulas (ECF) remains challenging. The purpose of this report is to describe a single-stage approach using combined microscopic enterolysis, pedicle seromuscular bowel flaps, mesh, fasciocutaneous, and myocutaneous flaps.

METHODS

Between 1990 and 2016 a retrospective review identified a total of 18 patients with an average age of 39 years (ranging 26-59 years). Thirteen cases were associated with trauma, four were complication of previous mesh repair, and one was after an aortic dissection. Average diameter of defect size was 22 cm (ranging 20-24 cm). Surgical technique involved enterolysis using microscope magnification, a pedicle seromuscular bowel flap to reinforce the bowel anastomosis, mesh, musculocutaneous, and fasciocutaneous flaps to reconstruct the abdominal wall.

RESULTS

Fifteen patients required rotational flaps with an average skin paddle area of 442.7 cm² (ranging 440 cm² -260 cm² ) and 10 patients required a serosal patch with an average length of 5 cm (ranging 4-6 cm). Complications included three wound dehiscence and one abdominal wall bulging. Flap survival was 100%. The majority of patients (12 out of 18) were able to resume normal activities, and the remaining (n = 6) were able to resume most activities. Functional outcome as assessed by 36-Item Short Form Survey (SF-36) physical function component questionnaire at 18-24 months follow up was 67.8% (ranging from 59 to 72%). Mean length of hospital stay was 2.2 weeks (ranging 1.4-2.7 weeks). Mean follow-up was 24 months (ranging 22-26 months) with clinical examination.

CONCLUSION

Microscopically assisted intra-abdominal dissection with resection of diseased bowel, replacement with well-vascularized tissue at the anastomosis site in, and reinforcement with mesh combined with pedicle musculocutaneous and fasciocutaneous flaps may be an alternative when other local reconstructive options have failed.

Emergent Laparoscopic Ventral Hernia Repairs

BACKGROUND

Emergent repairs of incarcerated and strangulated ventral hernia repairs (VHR) are associated with higher perioperative morbidity and mortality than those repaired electively. Despite increasing utilization of minimally invasive techniques in elective repairs, the role for laparoscopy in emergent VHR is not well defined, and its feasibility has been demonstrated only in single center studies.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program database (2009-2016) was queried for emergent VHR. Laparoscopic and open techniques were compared using univariate and multivariate analyses.

RESULTS

A total of 11,075 patients who underwent emergent ventral and incisional hernia repairs were identified: 85.5% open ventral hernia repair (OVHR), 14.5% laparoscopic ventral hernia repair (LVHR). Patients who underwent emergent OVHRs were older, more comorbid, and more likely to be septic at the time of surgery than those undergoing emergent LVHRs. Emergent OVHR patients were more likely to have minor complications (22.1% versus 11.0%; OR 1.7; 95% CI 1.069-2.834). After controlling for confounding variables, LVHR and OVHR had similar outcomes, with the exception of higher rates of superficial surgical site infection in OVHR (5.0% versus 1.8%; odd's ratio (OR) 2.7; 95% confidence interval (CI) 1.176-6.138). Following multivariate analysis, laparoscopic approach demonstrated similar outcomes in major complications, reoperation, and 30-d mortality compared to open repairs. However, when controlling for other confounding factors, LVHR had reduced length of stay compared to OVHR (6.7 versus 4.0 d; 1.6 d longer, standard error 0.77, P < 0.03).

CONCLUSIONS

Emergent LVHR is associated with fewer superficial surgical site infection and shorter length of stay than OVHR but no difference in major complications, reoperation or 30-d mortality is associated with LVHR in the emergency setting.

Infections associated with mesh repairs of abdominal wall hernias: Are antimicrobial biomaterials the longed-for solution?

The incidence of mesh-related infection after abdominal wall hernia repair is low, generally between 1 and 4%; however, worldwide, this corresponds to tens of thousands of difficult cases to treat annually. Adopting best practices in prevention is one of the keys to reduce the incidence of mesh-related infection. Once the infection is established, however, only a limited number of options are available that provides an efficient and successful treatment outcome. Over the past few years, there has been a tremendous amount of research dedicated to the functionalization of prosthetic meshes with antimicrobial properties, with some receiving regulatory approval and are currently available for clinical use. In this context, it is important to review the clinical importance of mesh infection, its risk factors, prophylaxis and pathogenicity. In addition, we give an overview of the main functionalization approaches that have been applied on meshes to confer anti-bacterial protection, the respective benefits and limitations, and finally some relevant future directions.

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.

Preparation of a nano- and micro-fibrous decellularized scaffold seeded with autologous mesenchymal stem cells for inguinal hernia repair

Prosthetic meshes used for hernioplasty are usually complicated with chronic pain due to avascular fibrotic scar or mesh shrinkage. In this study, we developed a tissue-engineered mesh (TEM) by seeding autologous bone marrow-derived mesenchymal stem cells onto nanosized fibers decellularized aorta (DA). DA was achieved by decellularizing the aorta sample sequentially with physical, mechanical, biological enzymatic digestion, and chemical detergent processes. The tertiary structure of DA was constituted with micro-, submicro-, and nanosized fibers, and the original strength of fresh aorta was retained. Inguinal hernia rabbit models were treated with TEMs or acellular meshes (AMs). After implantation, TEM-treated rabbit models showed no hernia recurrence, whereas AM-treated animals displayed bulges in inguinal area. At harvest, TEMs were thicker, have less adhesion, and have stronger mechanical strength compared to AMs (P<0.05). Moreover, TEM showed better cell infiltration, tissue regeneration, and neovascularization (P<0.05). Therefore, these cell-seeded DAs with nanosized fibers have potential for use in inguinal hernioplasty.

Partial versus complete removal of the infected mesh after abdominal wall hernia repair

BACKGROUND

To compare the results with complete mesh removal (CMR) versus partial mesh removal (PMR) in the treatment of mesh infection after abdominal wall hernia repair (AWHR).

METHODS

Retrospective review of all patients who underwent surgery for mesh infection between January 2004 and May 2014 at a tertiary center.

RESULTS

Of 3470 cases of AWHR, we reported 66 cases (1.9%) of mesh infection, and 48 repairs (72.7%) required mesh explantation. CMR was achieved on 38 occasions, while PMR was undertaken ten times. We observed more postoperative complications in CMR than PMR group (p = 0.04). Three patients with intestinal fistula were reoperated in postoperative period after a difficult mesh removal; one of them died due to multiple organ failure. The overall recurrence rate after explantation was 47.9%: recurrence was more frequent in CMR group (p = 0.001), although persistent or new mesh infection was observed more frequently with PMR (p = 0.001).

CONCLUSIONS

Although PMR has less postoperative morbidity, shorter duration of hospitalization and lower rate of recurrence than CMR, prosthetic infection persists in up to 50% of cases.

Self-gripping mesh versus fibrin glue fixation in laparoscopic inguinal hernia repair: a randomized prospective clinical trial in young and elderly patients

Laparoscopic transabdominal preperitoneal inguinal hernia repair is a safe and effective technique. In this study we tested the hypothesis that self-gripping mesh used with the laparoscopic approach is comparable to polypropylene mesh in terms of perioperative complications, against a lower overall cost of the procedure. We carried out a prospective randomized trial comparing a group of 30 patients who underwent laparoscopic inguinal hernia repair with self-gripping mesh versus a group of 30 patients who received polypropylene mesh with fibrin glue fixation. There were no statistically significant differences between the two groups with regard to intraoperative variables, early or late intraoperative complications, chronic pain or recurrence. Self-gripping mesh in transabdominal hernia repair was found to be a valid alternative to polypropylene mesh in terms of complications, recurrence and postoperative pain. The cost analysis and comparability of outcomes support the preferential use of self-gripping mesh.

Focus on the prophylaxis, epidemiology and therapy of methicillin-resistant Staphylococcus aureus surgical site infections and a position paper on associated risk factors: the perspective of an Italian group of surgeons

BACKGROUND

The aim of this research was to study the epidemiology, microbiology, prophylaxis, and antibiotic therapy of surgical site infections (SSIs), especially those caused by methicillin-resistant Staphylococcus aureus (MRSA), and identify the risk factors for these infections. In Italy SSIs occur in about 5 % of all surgical procedures. They are predominantly caused by staphylococci, and 30 % of them are diagnosed after discharge. In every surgical specialty there are specific procedures more associated with SSIs.

METHODS

The authors conducted a systematic review of the literature on SSIs, especially MRSA infections, and used the Delphi method to identify risk factors for these resistant infections.

RESULTS

Risk factors associated with MRSA SSIs identified by the Delphi method were: patients from long-term care facilities, recent hospitalization (within the preceding 30 days), Charlson score > 5 points, chronic obstructive pulmonary disease and thoracic surgery, antibiotic therapy with beta-lactams (especially cephalosporins and carbapenem) and/or quinolones in the preceding 30 days, age 75 years or older, current duration of hospitalization >16 days, and surgery with prothesis implantation. Protective factors were adequate antibiotic prophylaxis, laparoscopic surgery and the presence of an active, in-hospital surveillance program for the control of infections. MRSA therapy, especially with agents that enable the patient's rapid discharge from hospital is described.

CONCLUSION

The prevention, identification and treatment of SSIs, especially those caused by MRSA, should be implemented in surgical units in order to improve clinical and economic outcomes.

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.

Evidence for Replacement of an Infected Synthetic by a Biological Mesh in Abdominal Wall Hernia Repair

Introduction

The incidence of deep infection using a synthetic mesh in inguinal hernia repair is low and reported to be well below 1%. This is in contrast to incisional hernia surgery where the reported incidence is 3% respective 13% comparing laparoscopic to open mesh repair reported in a Cochrane review. Main risk factors were long operation time, surgical site contamination, and early wound complications. An infected mesh can be preserved using conservative treatment were negative pressure wound therapy (VAC^®) could play an important role. If strategy fails, the mesh needs to be removed. This review aims to look at evidence for situations were a biological mesh would work as a replacement of a removed infected synthetic mesh.

Materials and methods

A literature search of the Medline database was performed using the PubMed search engine. Twenty publications were found relevant for this review.

Results

For studies reviewed three options are presented: removal of the infected synthetic mesh alone, replacement with either a new synthetic or a new biological mesh. Operations were all performed at specialist centers. Removal of the mesh alone was an option limited to inguinal hernias. In ventral/incisional hernias, the use of a biological mesh for replacement resulted in a very high recurrence rate, if bridging was required. Either a synthetic or a biological mesh seems to work as a replacement when fascial closure can be achieved. Evidence is though very low.

Conclusion

When required, either a synthetic or a biological mesh seems to work as a replacement for an infected synthetic mesh if the defect can be closed. It is, however, not recommended to use a biological mesh for bridging. Mesh replacement surgery is demanding and is recommended to be performed in a specialist center.

Naturally derived and synthetic scaffolds for skeletal muscle reconstruction

Skeletal muscle tissue has an inherent capacity for regeneration following injury. However, severe trauma, such as volumetric muscle loss, overwhelms these natural muscle repair mechanisms prompting the search for a tissue engineering/regenerative medicine approach to promote functional skeletal muscle restoration. A desirable approach involves a bioscaffold that simultaneously acts as an inductive microenvironment and as a cell/drug delivery vehicle to encourage muscle ingrowth. Both biologically active, naturally derived materials (such as extracellular matrix) and carefully engineered synthetic polymers have been developed to provide such a muscle regenerative environment. Next generation naturally derived/synthetic "hybrid materials" would combine the advantageous properties of these materials to create an optimal platform for cell/drug delivery and possess inherent bioactive properties. Advances in scaffolds using muscle tissue engineering are reviewed herein.

Blood vessel matrix seeded with cells: a better alternative for abdominal wall reconstruction-a long-term study

PURPOSE

The aim of this study was to present abdominal wall reconstruction using a porcine vascular graft seeded with MSC (mesenchymal stem cells) on rat model.

MATERIAL AND METHODS

Abdominal wall defect was prepared in 21 Wistar rats. Acellular porcine-vascular grafts taken from aorta and prepared with Triton X were used. 14 aortic grafts were implanted in place, of which 7 grafts were seeded with rat MSC cells (Group I), and 7 were acellular grafts (Group II). As a control, 7 standard polypropylene meshes were used for defect augmentation (Group III). The assessment method was performed by HE and CD31 staining after 6 months. The mechanical properties have been investigated by Zwick&Roell Z0.5.

RESULTS

The strongest angiogenesis and lowest inflammatory response were observed in Group I. Average capillaries density was 2.75, 0.75, and 1.53 and inflammatory effect was 0.29, 1.39, and 2.72 for Groups I, II, and III, respectively. The means of mechanical properties were 12.74 ± 1.48, 7.27 ± 1.56, and 14.4 ± 3.7 N/cm in Groups I and II and control, respectively.

CONCLUSIONS

Cell-seeded grafts have better mechanical properties than acellular grafts but worse than polypropylene mesh. Cells improved mechanical and physiological properties of decellularized natural scaffolds.

Use of Acellular Dermal Matrix Combined with a Component Separation Technique for Repair of Contaminated Large Ventral Hernias: A Possible Ideal Solution for this Clinical Challenge

Repair of large contaminated ventral hernias is always challenging because of massive loss of muscular and fascial tissues, high risk of surgical infection and recurrence, and contraindication to use of a permanent prosthesis. This study reviewed retrospectively data of 35 patients with contaminated large ventral hernias who received repair using acellular dermal matrix combined with a component separation technique from 2009 to 2011. Twenty-one males and 14 females were identified with a mean age of 45.5 ± 12.5 years and a mean body mass index of 22.5 ± 5.8 kg/m2. Simultaneously, nine patients underwent bowel fistula resection, 13 patients underwent ostomy takedown, five patients underwent recurrent colon cancer dissection, and eight patients underwent infectious permanent mesh removal and wound débridement. Mean defect size was 125.0 ± 23.5 cm2. The aponeurosis of the external oblique muscle was transected and separated from internal oblique muscle to reach abdominal closure. A cellular dermal matrix was placed in an onlay fashion and mean mesh size was 300.0 ± 65.0 cm2. Thirty-five patients had a mean follow-up period of 36.5 ± 12.5 months. Wound bleeding and partial dehiscence occurred at 36 hours post-operatively. Five patients reported abdominal wall pain during the first postoperative month. Five patients developed surgical site infection. Four patients were detected to develop seroma with volume more than 20 mL by B-ultrasound examination. No recurrence and chronic foreign body sensation were followed up. Use of acellular dermal matrix combined with a component separation technique is safe and efficient management for repair of contaminated large ventral hernia, in which permanent prosthesis placement is contraindicated.

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.

The impact of diclofenac and ibuprofen on biofilm formation on the surface of polypropylene mesh

PURPOSE

The difficulties related to treatment of deep surgical site infection involve formation of biofilm on the surface of synthetic material. It is considered that in treatment of infections involving formation of biofilm, concomitant therapy shall be applied covering anti-inflammatory drugs. The purpose of the work was to assess the impact of diclofenac and ibuprofen on bacterial biofilm formation on the surface of monofilament polypropylene mesh.

MATERIALS AND METHODS

The study involved 70 strains of Staphylococcus aureus and 70 strains of Escherichia coli isolated from different patients and those which differ with chromosomal DNA pattern within the species. The assessment of the impact of non-steroidal anti-inflammatory drugs (NSAIDs) on biofilm formation was carried out with the use of qualitative method (TTC reduction), quantitative (tenfold serial dilution) and with the use of scanning electron microscope (SEM).

RESULTS

In the qualitative assessment, after incubation in the medium containing NSAIDs statistically significant growth of S. aureus strain amount and E. coli which poorly make up biofilm was stated. Quantitative examination indicated characteristic decrease of the number of colony forming units in 1 ml of the suspension isolated from bacterial biofilm formed as a result of incubation of isolates in the medium with the addition of examined NSAIDs in comparison to biofilm from control regimen. In the examination with the use of SEM it was stated that the effect of isolates incubation in the medium with NSAIDs was decrease of the number of bacteria adjacent to the biomaterial surface.

CONCLUSIONS

Diclofenac and ibuprofen in the concentration obtained in the serum limit the formation of biofilm by S. aureus and E. coli.

Outcome of the patients with chronic mesh infection following open inguinal hernia repair

Purpose

Hernia repairs are the most common elective abdominal wall procedures performed by general surgeons. The use of a mesh has become the standard for hernia repair surgery. Herein, we discuss a management strategy for chronic mesh infections following open inguinal hernia repair with onlay prosthetic mesh.

Methods

In this study, 15 patients with chronic mesh infections following open inguinal hernia repairs were included. The medical records of these patients were retrospectively reviewed and information regarding presentation, type of previous hernia repair, type of mesh, operative findings and bacteriological examination results were obtained. In all cases, the infected mesh was removed completely and the patients were treated with antibiotic regimens and local wound care.

Results

Fifteen mesh removals due to chronic infection were performed between January 2000 and March 2012. The mean interval of hernia repair to mesh removal was 49 months. All patients were followed up for a median period of 62 months (range, 16 to 115 months). In all patients, the infections were resolved successfully and none were persistent or recurrent. However, one patient developed recurrent hernia and one developed nerve injury.

Conclusion

Chronic mesh infection following hernia repair mandates removal of the infected mesh, which rarely results in hernia recurrence.

Radical tumor excision and immediate abdominal wall reconstruction in patients with aggressive neoplasm compromised full-thickness lower abdominal wall

BACKGROUND

Radical tumor resection and immediate lower abdominal wall reconstruction in patients with aggressive neoplasm invading full-thickness abdominal wall are challenging because of their close proximity and possible invasion to bone and great vessels, as well as consequent giant defect.

METHODS

Data on 16 patients were reviewed retrospectively. Radical neoplasm resection and immediate abdominal wall reconstruction using the combined technique of intraperitoneal mesh placement, sublay technique, pedicled great omentum flap, and rotation skin graft were performed.

RESULTS

Sixteen patients underwent radical abdominal wall neoplasm resection, achieving clear margin of >3 cm. The mean size of consequent giant defect was 226.5 ± 65.5 cm(2), with a mean polypropylene mesh size of 160.7 ± 40.5 cm(2) and a mean compound mesh size of 330.8 ± 100.2 cm(2). Sixteen patients had a mean follow-up duration of 32.5 ± 12.5 months. Four patients developed incisional infections, and 1 patient died of several metastatic lesions 24 months postoperatively. No ventral hernia and abdominal wall recurrence were observed.

CONCLUSIONS

Radical neoplasm resection and immediate abdominal wall reconstruction are appropriate for patients with aggressive neoplasm in the lower abdominal wall.

Don't be scared: insert a mesh!

Mesh repair is now the gold standard technique of repair on incisional hernias. Infection of the mesh is a challenging complication of this type of repair. The risk of mesh infection has been shown to be greater in case of complicated hernia. We present the case of a 64 years old female who presented with an incarcerated incisional hernia with bowel infarction. Treated with a non absorbable mesh repair, she developed mesh infection. The infection was successively treated with simple drainage. This case and review of relevant literature seem to be an indication that mesh repair could still be considered in cases of complicated hernia. Simple drainage usually helps manage the cases of mesh infection.

Salvage of an infected titanium mesh in a large incisional ventral hernia using medicinal honey and vacuum-assisted closure: a case report and literature review

The overall reported percentage of mesh infections is 1.3%. Infections after incisional ventral hernia repair depend on many factors. Salvaging an infected mesh should be the priority, because serious complications are reported following mesh removal. In this case report, a methicillin-resistant Staphylococcus aureus (MRSA)-infected titanium mesh was salvaged by a novel technique, not requiring removal. The combination of vacuum-assisted closure (VAC™ therapy) of the wound and medical honey (L-Mesitran™) proved to be successful in leaving the mesh in situ. We report the successful management of this infected titanium mesh and review the literature regarding the possible pathogenetic mechanisms and treatment options.

[Laparoscopic repair of abdominal wall hernias]

Repair of abdominal wall defects is a challenge for all general surgeons and a variety of methods have been described in the past. Traditionally, primary suture repair was shown to have a high recurrence rate in long-term follow-up studies. Herniorrhaphies that apply a large prosthetic mesh are appear to have a lower failure rate, but extensive dissection of soft tissue contributes to an increased incidence of wound infections and wound-related complications. The method of laparoscopic incisional hernia repair was developed in the early 1990s. This technique is based on the same physical and surgical principles as the open underlay procedure. The laparoscopic intraperitoneal onlay mesh (IPOM) technique and mesh materials were developed further in subsequent years, and there have been numerous reports on successful use of the IPOM technique even for extremely large hernia openings in obese and elderly patients. Reduced surgical trauma and lower infection and recurrence rates are key advantages of the minimally invasive repair. Therefore, this operation has increased in popularity promising shorter hospital stay, improved outcome, and fewer complications than traditional open procedures.