Abdominal hernia repair with bridging acellular dermal matrix--an expensive hernia sac

Outcomes of synthetic and biologic mesh in abdominal wall reconstruction: A propensity-matched analysis in Centers for Disease Control and Prevention class 1 and 2 wounds

INTRODUCTION

The choice of biologic compared with synthetic mesh in abdominal wall reconstruction remains controversial, especially in Centers for Disease Control and Prevention class 1 and 2 wounds. This study evaluated wound complications and hernia recurrence with a 2:1 propensity-matched sample and extended follow-up.

METHODS AND PROCEDURES

A prospectively maintained abdominal wall reconstruction database was queried for patients undergoing open abdominal wall reconstruction using biologic or synthetic mesh in Centers for Disease Control and Prevention class 1 and 2 wounds. Patients receiving synthetic or biologic mesh were propensity score matched in a 2:1 fashion. Univariate, bivariate, and inferential analyses were conducted. Unless stated, data are reported as biologic compared with synthetic.

RESULTS

In total, 519 patients were compared, 173 with biologic and 346 with synthetic mesh. Defect size (215.2 ± 153.6 cm2 vs 251.5 ± 284.3 cm2), body mass index (33.6 ± 9 kg/m2 vs 34 ±17.7 kg/m2), and comorbidities were well matched (all P > .05). Although Centers for Disease Control and Prevention wound class was used in the match, it was significantly different between groups (Centers for Disease Control and Prevention 1:43.4% vs 81.2%, Centers for Disease Control and Prevention 2:56.6% vs 18.8%; P < .001). The rate of component separation (40.1% vs 44.2%; P = .397), fascial closure (97.7% vs 98.3%; P = .738), and panniculectomy (33.5% vs 29.2%; P = .315) were similar. Mesh size was also similar (816.4 ± 555.5 vs 892.2 ± 487.8 cm2; P = .112). Wound complications were equal, including wound breakdown (10.5% vs 7.5%; P = .315), wound cellulitis (5.2% vs 5.8%; P = .843), wound infection (7.5% vs 4.6%; P = .223), seroma requiring intervention (6.4% vs 7.8%; P = .597), and mesh infection (1.2% vs 0.9%; P > .999). The biologic group had an increased length of stay (6.8 ± 5.5 days vs 5.4 ± 2.3 days; P < .001) and greater hospital charges ($82,181 ± 50,356 vs $62,221 ± 26,817 USD; P < .001). Mean follow-up after biologic repair was longer (33.9 ± 36.6 months vs 23.3 ± 32.3 months; P < .001). Hernia recurrence between the biologic and synthetic groups was not significantly different (2.9% vs 1.4%; P = .313). On multivariable regression, wound complications were predictive of recurrence, and panniculectomy was predictive of wound complications.

CONCLUSION

In a 2:1 matched analysis of Centers for Disease Control and Prevention 1 and 2 wounds with nearly 3-years of follow-up, biologic and synthetic mesh had similar rates of wound complications and recurrence in abdominal wall reconstruction.

Nanotechnology approaches in abdominal wall reconstruction: A narrative review about scaffold and meshes

Repairing abdominal wall defects poses challenges for surgeons. Although mesh reinforcement is commonly used for primary repair, nanotechnology has emerged as a promising approach for developing innovative repair techniques. Most research in this area focuses on fabricating scaffolds designed specifically for abdominal wall repair, particularly in cases of hernia. These scaffolds are engineered to replicate the structure and function of the native extracellular matrix. This review aimed to summarize the existing studies on the application of nanotechnology in abdominal wall reconstruction following injury or repair.

Staged abdominal wall reconstruction in the setting of complex gastrointestinal reconstruction

PURPOSE

Literature on one- versus two-staged abdominal wall reconstruction (AWR) with complex gastrointestinal reconstruction (GIR) is limited to single-arm case series with a focus on patients who complete all planned stages. Herein, we describe our experience with both one- and two-staged approaches to AWR/GIR, with attention to those who did not complete both intended stages.

METHODS

A retrospective review of prospectively collected data was conducted to identify patients who underwent a one- or two-stage approach to GIR/AWR from 2013 to 2020. The one-stage approach included GIR and definitive sublay mesh herniorrhaphy. The two-stage approach included Stage 1 (S1)-GIR and non-definitive herniorrhaphy and Stage 2 (S2)-definitive sublay mesh herniorrhaphy.

RESULTS

Fifty-four patients underwent GIR/AWR: 20 (37.0%) underwent a planned 1-stage operation while 34 (63.0%) underwent S1 of a planned 2-stage approach. Patients assigned to the 2-stage approach were more likely to be smokers, have a history of mesh infection, have an enterocutaneous fistula, and a contaminated wound class (p<0.05). Of the 34 patients who underwent S1, 12 (35.3%) completed S2 during the mean follow-up period of 44 months while 22 (64.7%) did not complete S2. Of these, 10 (45.5%) developed hernia recurrence but did not undergo S2 secondary to elective nonoperative management (40%), pending preoperative optimization (30%), additional complex GIR (10%), hernia-related incarceration requiring emergent surgery (10%), or unrelated death (10%). No differences in outcome including SSI, SSO, readmission, and recurrence were noted between the 12 patients who completed the two-stage approach and the 20 patients who completed a one-stage approach, despite increased risk factors for complications in the 2-stage group (p>0.05).

CONCLUSION

Planned two-stage operations for GIR/AWR may distribute operative complexity and post-operative morbidity into separate surgical interventions. However, many patients may never undergo the intended definitive S2 herniorrhaphy. Future evaluation of 1- versus 2-stage GIR/AWR is needed to clarify indications for each approach. This work must also consider the frequent deviations from intended clinical course demonstrated in this study.

The Use of Inlay Bridge of the Posterior Fascia as Adjuvants to a Modified Rives-Stoppa Repair for Difficult Abdominal Wall Hernias

BACKGROUND

Major abdominal wall defects remain a highly morbid complication. Occasionally a fascial defect is encountered, that despite all surgical efforts, is unable to completely approximate at the midline. Here we describe our method and outcomes of using a bridging mesh when the posterior fascia was unable to be approximated during the repair of large postoperative ventral hernias using the modified Rives-Stoppa technique.

METHODS

A retrospective review was conducted looking at all the open abdominal wall hernia repairs between 2014 and 2020. The cohort of patients who had a bridge placed in addition to the traditional open modified Rives-Stoppa repair were used for this study.

RESULTS

Nineteen patients had a mesh inlay bridge placed in addition to a modified Rives-Stoppa repair with a sublay (retrorectus) Ultrapro mesh. For the inlay mesh 13 Symbotex composite meshes were placed and 6 Vicryl meshes used. The average surface area of the defect was 358.1 cm^2. The average length of hospitalization was 8.8 days with a range of 3-24 days. During the immediate postoperative course there were 6 minor complications. During the follow-up period there were 2 recurrences.

DISCUSSION

The use of inlay mesh bridge as an adjuvant to a modified Rives-Stoppa repair with a sublay ultrapro mesh is an effective technique for difficult abdominal wall repairs where the posterior fascia is unable to be approximated without tension.

Outcomes of Abdominal Wall Reconstruction with a Bovine versus a Porcine Acellular Dermal Matrix: A Propensity Score-Matched Analysis

BACKGROUND

Abdominal wall reconstruction (AWR) is one of the most commonly performed procedures, yet large comparative studies comparing outcomes of AWR using bovine acellular dermal matrix (BADM) and porcine acellular dermal matrix (PADM) are lacking.

METHODS

In this retrospective cohort study of patients who underwent AWR from March of 2005 to June of 2019, the primary comparative outcome measure was hernia recurrence with BADM versus PADM. The secondary outcome was the incidence of surgical-site occurrence (SSO) and surgical-site infection. A propensity score matching approach was applied to compare the clinical outcomes between the two study groups.

RESULTS

The authors identified 725 patients who underwent AWR using BADM (50.5%) or PADM (49.5%). Their mean ± SD age was 59.8 ± 11.5 years, mean body mass index was 31.4 ± 6.7 kg/m 2 , and mean follow-up time was 42 ± 29 months. With propensity score matching, 219 matched pairs were identified. Hernia recurrence rates in BADM (11.4%) and PADM (13.7%) groups did not differ significantly ( P = 0.793). SSO (26.5% versus 29.2%; P = 0.518) and SSI (13.2% versus 11%; P = 0.456) rates did not differ significantly in the PADM and BADM groups, respectively. Conditional logistic regression model and marginal Cox proportional hazards regression model determined that type of acellular dermal matrix was not significantly associated with SSOs (adjusted OR, 1.11; 95% CI, 0.74 to 1.70; P = 0.589) or hernia recurrence (adjusted hazard ratio, 0.85; 95% CI, 0.50 to 1.42; P = 0.52).

CONCLUSIONS

Both BADMs and PADMs provide durable, long-term outcomes. The hernia recurrence and postoperative surgical complication rates were not significantly different between BADM and PADM.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

Bridged repair of large ventral hernia defects using an ovine reinforced biologic: A case series

Introduction

Of all hernia types, large ventral hernias have the most impact on patient quality of life, however they are also the most difficult type of hernia to repair and are associated with high rates of complications. This case series describes repair of large ventral hernias with an ovine reinforced biologic in a complex patient cohort with comorbidities and concomitant procedures.

Methods

The author performed bridged repair with an ovine reinforced biologic in 19 consecutive high-risk patients over a 5-year period. In all cases the reinforced biologic was used as an underlay.

Outcomes

Of the 19 patients, six (32%) experienced a surgical site occurrence including infection, seroma, abscess, fistula, bioloma, or bowel obstruction. Three patients (16%) had recurrences with two out of three of the recurrences occurring within 6 months of surgery.

Conclusions

Rates of SSO's and recurrences using ovine reinforced tissue matrix (RTM) were in line with or better than other published studies of bridged repair utilizing biologic or synthetic mesh reinforcement. Ovine RTM's should therefore be considered in complex large ventral hernia repairs.

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Large ventral hernias greatly impact patient quality of life.

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In some cases, large ventral hernias necessitate bridged repair with mesh.

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19 patients received bridged repair with an ovine reinforced matrix.

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Mean follow up of 23 months showed low complication and recurrence rates.

Amniotic fluid allograft enhances the host response to ventral hernia repair using acellular dermal matrix

Ventral hernia repair (VHR) with acellular dermal matrix (ADM) has high rates of recurrence that may be improved with allogeneic growth factor augmentation such as amniotic fluid allograft (AFA). We hypothesized that AFA would modulate the host response to improve ADM incorporation in VHR. Lewis rats underwent chronic VHR with porcine ADM alone or with AFA augmentation. Tissue harvested at 3, 14, or 28 days was assessed for region-specific cellularity, and a validated histomorphometric score was generated for tissue incorporation. Expression of pro-inflammatory (Nos1, Tnfα), anti-inflammatory (Arg1, Il-10, Mrc1) and tissue regeneration (Col1a1, Col3a1, Vegf, and alpha actinin-2) genes were quantified using quantitative reverse-transcription polymerase chain reaction. Amniotic fluid allograft treatment caused enhanced vascularization and cellularization translating to increased histomorphometric scores at 14 days, likely mediated by upregulation of pro-regeneration genes throughout the study period and molecular evidence of anti-inflammatory, M2-polarized macrophage phenotype. Collectively, this suggests AFA may have a therapeutic role as a VHR adjunct.

Changes in the abdominal wall after anterior, posterior, and combined component separation

KEY MESSAGE

Knowledge of the changes that occur in the abdominal wall after component separation (CS) is essential for understanding the mechanisms of action of the various CS techniques, the changes observed on computed tomography images, and, perhaps most importantly, the anatomic and physiologic changes observed in patients who have undergone CS. Purpose Component separation (CS) techniques are essential adjuncts during most abdominal wall reconstructions. They allow the fulfillment of most modern abdominal wall reconstruction principles, especially primary closure of defects and linea alba restoration under physiologic tension. Knowledge of the post-CS abdominal wall changes is essential to understanding the mechanism of action of the various types of CS, the changes observed on computed tomographic images, and, perhaps most importantly, the anatomic and physiologic changes following CS techniques. Methods A systematic review of the literature was conducted using the PubMed database and other sources to identify articles describing abdominal wall changes after CS Results After excluding non-pertinent articles, 14 articles constituted the basis for this review.  Conclusions After reviewing the literature on post CS abdominal wall changes, we conclude the following: (1)The external oblique muscle is significantly displaced laterally after anterior CS, the transversus abdominis muscle shifts very little after posterior CS, and muscle trophism is generally maintained after both techniques. These findings are consistent for both open and minimally invasive CS. (2) The anatomy and physiology of abdominal wall muscles are preserved mainly by the muscles' overlapping function and their ability to undergo compensatory trophism after midline restoration (reloading). (3) Well-performed CS techniques have a low risk of producing bulging and semilunar line hernias. (4) Anterior and posterior CS techniques probably have different mechanisms of action. (5) Current studies on how the nutritional status and postoperative conditioning can alter abdominal wall changes after CS and the mechanisms of the actions involved in anterior and posterior CS are underway.

A non-linear ensemble model-based surgical risk calculator for mixed data from multiple surgical fields

BACKGROUND

The misestimation of surgical risk is a serious threat to the lives of patients when implementing surgical risk calculator. Improving the accuracy of postoperative risk prediction has received much attention and many methods have been proposed to cope with this problem in the past decades. However, those linear approaches are inable to capture the non-linear interactions between risk factors, which have been proved to play an important role in the complex physiology of the human body, and thus may attenuate the performance of surgical risk calculators.

METHODS

In this paper, we presented a new surgical risk calculator based on a non-linear ensemble algorithm named Gradient Boosting Decision Tree (GBDT) model, and explored the corresponding pipeline to support it. In order to improve the practicability of our approach, we designed three different modes to deal with different data situations. Meanwhile, considering that one of the obstacles to clinical acceptance of surgical risk calculators was that the model was too complex to be used in practice, we reduced the number of input risk factors according to the importance of them in GBDT. In addition, we also built some baseline models and similar models to compare with our approach.

RESULTS

The data we used was three-year clinical data from Surgical Outcome Monitoring and Improvement Program (SOMIP) launched by the Hospital Authority of Hong Kong. In all experiments our approach shows excellent performance, among which the best result of area under curve (AUC), Hosmer-Lemeshow test ([Formula: see text]) and brier score (BS) can reach 0.902, 7.398 and 0.047 respectively. After feature reduction, the best result of AUC, [Formula: see text] and BS of our approach can still be maintained at 0.894, 7.638 and 0.060, respectively. In addition, we also performed multiple groups of comparative experiments. The results show that our approach has a stable advantage in each evaluation indicator.

CONCLUSIONS

The experimental results demonstrate that NL-SRC can not only improve the accuracy of predicting the surgical risk of patients, but also effectively capture important risk factors and their interactions. Meanwhile, it also has excellent performance on the mixed data from multiple surgical fields.

Comparison of porcine and human acellular dermal matrix outcomes in wound healing: a deep dive into the evidence

Acellular dermal matrices (ADM) are a novel graft. The goal of this systematic review is to evaluate the evidence behind differences in human and porcine ADM, irrelevant of manufacturing method, and to determine if there is enough of an evidence base to change clinical practice. An extensive literature search was performed through MEDLINE and Embase with search terms defining a population, intervention and outcome. Title and abstract exclusion were performed with other exclusion criteria. In 191 articles were found after exclusion of duplicates, with only 29 remaining following exclusions. Ten studies were found to have level I and II evidence (I=3, II=8), of which two were histopathological, one was an animal model, one was a systematic review, and six were clinical. The remaining studies were reviewed and considered for discussion, but did not hold high enough standards for medical evidence. Strong clinical evidence already exists for the use of human ADM, but questions of access, cost, and ethics require consideration of a xenograft. Histopathologically, evidence suggests minimal long-term differences between human and porcine ADM, although there is a short acute immune response with porcine ADM. Clinically, there is limited difference in outcomes, with a small range in effect of different ADM preparations. Considering the effectiveness of ADM in wound healing, more high-level research with appropriate statistical analysis to facilitate a future meta-analysis is recommended to justify a transition from human to porcine ADM.

Topological Structure Design and Fabrication of Biocompatible PLA/TPU/ADM Mesh with Appropriate Elasticity for Hernia Repair

The meshes for hernia repair result in many problems that are related to complications including chronic pain and limited movement due to inadequate mechanical strength, non-absorbability, or low elasticity. In this study, degradable polylactic acid (PLA), synthetic thermoplastic polyurethane (TPU), and acellular dermal matrix (ADM) powders are combined to prepare a novel PLA/TPU/ADM mesh with three different topological structures (square, circular, and diamond) by 3D printing. The physicochemical properties and structural characteristics of mesh are studied, the results show that the diamond structure mesh with the pore size of 3 mm has sufficient elasticity and tensile strength, which provides the efficient mechanical strength required for hernia repair (16 N cm^-1 ) and the value more than polypropylene(PP) mesh. Besides, in vitro and in vivo experiments demonstrate human umbilical vein endothelial cells could successfully proliferate on the PLA/TPU/ADM mesh whose biocompatibility with the host is shown using a rat model of abdominal wall defect. In conclusion, the results of this study demonstrate that the PLA/TPU/ADM mesh may be considered a good choice for hernia repair as its potential to overcome the elastic and strength challenges associated with a highly flexible abdominal wall, as well as its good biocompatibility.

Preventing Recurrence in Clean and Contaminated Hernias Using Biologic Versus Synthetic Mesh in Ventral Hernia Repair: The PRICE Randomized Clinical Trial

OBJECTIVE

The aim of this study was to evaluate which mesh type yields lower recurrence and complication rates after ventral hernia repair.

SUMMARY BACKGROUND DATA

More than 400,000 ventral hernia repairs are performed annually in the United States. Although the most effective method for repairing ventral hernias involves using mesh, whether to use biologic mesh versus synthetic mesh is controversial.

METHODS

Single-blind, randomized, controlled, pragmatic clinical trial conducted from March 2014 through October 2018; 165 patients enrolled with an average follow up of 26 months. Patients were randomized 1:1 to have their ventral hernias repaired using either a biologic (porcine) or synthetic (polypropylene) mesh. The primary study outcome measure was hernia recurrence at 2 years.

RESULTS

A total of 165 patients (68 men), mean age 55 years, were included in the study with a mean follow-up of 26 months. An intention-to-treat analysis noted that hernias recurred in 25 patients (39.7%) assigned to biologic mesh and in 14 patients (21.9%) assigned to synthetic mesh (P = 0.035) at 2 years. Subgroup analysis identified an increased rate of hernia recurrence in the biologic versus the synthetic mesh group under contaminated wound conditions (50.0% vs 5.9%; P for interaction = 0.041). Postoperative complication rates were similar for the 2 mesh types.

CONCLUSIONS

The risk of hernia recurrence was significantly higher for patients undergoing ventral hernia repair with biologic mesh compared to synthetic mesh, with similar rates of postoperative complications. These data indicate that the use of synthetic mesh over biologic mesh to repair ventral hernias is effective and can be endorsed, including under contaminated wound conditions.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02041494.

Addition of platelet-rich plasma supports immune modulation and improved mechanical integrity in Alloderm mesh for ventral hernia repair in a rat model

The recurrence of ventral hernias continues to be a problem faced by surgeons, in spite of efforts toward implementing novel repair techniques and utilizing different materials to promote healing. Cadaveric acellular dermal matrices (Alloderm) have shown some promise in numerous surgical subspecialties, but these meshes still suffer from subsequent failure and necessitation of re-intervention. Here, it is demonstrated that the addition of platelet rich plasma to Alloderm meshes temporally modulates both the innate and cytotoxic inflammatory responses to the implanted material. This results in decreased inflammatory cytokine production at early time points, decreased matrix metalloproteinase expression, and decreased CD8+ T cell infiltration. Collectively, these immune effects result in a healing phenotype that is free from mesh thinning and characterized by increased material stiffness.

The worst-case scenario: Bridging repair with a biologic mesh in high-risk patients with very large abdominal wall hernias-a prospective multicenter study

BACKGROUND

While modern techniques allow midline fascial closure for most abdominal hernias, a bridge repair with mesh may be the only alternative in very large defects. When the risk of infection is high, the use of prosthetic mesh is controversial. We aim to examine outcomes after bridge repair of very large abdominal hernias at high risk for postoperative infection with a second-generation biologic mesh.

METHODS

Prospective, multicenter, single-arm study of patients with very large abdominal hernias who received bridge repair with a neonatal bovine dermis mesh. Primary outcome was hernia recurrence, as identified on computed tomography 1 year after the operation. Secondary outcomes included mesh laxity, surgical site occurrences, and any other mesh-related complications. Independent risk factors of the outcomes were determined by univariate and multivariable analyses.

RESULTS

A total of 117 bridge repair patients were enrolled with a mean defect size of 442.5 ± 254.2 cm². The patients were predominantly obese (mean body mass index 36.5 ± 10.5) and with multiple comorbidities (Charlson comorbidity index 3 ± 2.5). Hernia recurrence was identified in 24 (20.5%) patients. An infected mesh at the index operation was an independent predictor of hernia recurrence, whereas obesity was an independent predictor of the pooled endpoint of recurrence and mesh laxity. Surgical site occurrences were recorded in 36.8% of the patients, and no independent risk factors were identified.

CONCLUSION

In patients with very large abdominal hernias and at high risk for postoperative infection, who cannot undergo midline fascial closure, a bridge repair with neonatal bovine dermis mesh offers an acceptable profile in terms of hernia recurrence and wound occurrences.

Fundamentals of Extracellular Matrix Biomaterial Assimilation: Effect of Suture Type on Attachment Strength and Cell Repopulation

The clinical results with extracellular matrix biomaterials are confounded by expectations of material response based on years of experience with permanent or degradable synthetic polymers. However, the remodeling or assimilation of extracellular matrix biomaterials is dictated by cell-mediated processes rather than fibrous encapsulation or hydrolytic degradation. Previously, we found that tissue adherence and revascularization were dictated by proximity with de-epithelialized host tissue. We now investigate the effects of polymer and fixation type on attachment strength and rate of cell repopulation in an intra-abdominal implant model.

Combining anterior and posterior component separation for extreme cases of abdominal wall reconstruction

PURPOSE

The closure of midline in abdominal wall incisional hernias is an essential principle. In some exceptional circumstances, despite adequate component separation techniques, this midline closure cannot be achieved. This study aims to review the results of using both anterior and component separation in these exceptional cases.

METHODS

We reviewed our experience using the combination of both anterior and posterior component separation in the attempt to close the midline. Our first step was to perform a TAR and a complete extensive dissection of the retromuscular preperitoneal plane developed laterally as far as the posterior axillary line. When the closure of midline was not possible, an external oblique release was made. A retromuscular preperitoneal reinforcement was made with the combination of an absorbable mesh and a 50 × 50 polypropylene mesh.

RESULTS

Twelve patients underwent anterior and posterior component separation. The mean hernia width was 23.5 ± 5. The majority were classified as severe complex incisional hernia and had previous attempts of repair. After a mean follow-up of 27 months (range 8-45), no case of recurrence was registered. Only one patient (8.33%) presented with an asymptomatic bulging in the follow-up. European Hernia Society's quality of life scores showed a significant improvement at 2 years postoperatively in the three domains: pain (p = 0.01), restrictions (p = 0.04) and cosmetic (p = 0.01).

CONCLUSIONS

The combination of posterior and anterior component separation can effectively treat massive and challenging cases of abdominal wall reconstruction in which the primary midline closure is impossible to achieve despite appropriate optimization of surgery.

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.

Erratum: Addendum: Abdominal Wall Reconstruction: An Integrated Approach

[This corrects the article DOI: 10.1055/s-0038-1667062.].

A novel tool to evaluate bias in literature on use of biologic mesh in abdominal wall hernia repair

PURPOSE

Biologic meshes are being increasingly used for abdominal hernia repair in high-risk patients or patients with a previous history of wound infection, due to their infection-resistant properties. Several studies have been carried out to assess whether biologic mesh is superior to synthetic mesh, as well as to establish guidelines for their use. Unfortunately, most of these studies were not rigorously designed and were vulnerable to different types of bias. The systematic reviews that have been published so far on this topic contain the same biases and limitations of the primary articles that are analyzed. The lack of a literature review on the bias on the use of biological mesh prompted us to conduct the literature search, assessment and plan this article.

METHODS

We performed a literature search in PubMed, Embase and Cochrane databases of systematic reviews on biologic mesh for ventral hernia repair. The literature review was conducted using the Population, Intervention, Comparisons, Outcomes and Design approach. We identified 40 studies that matched the stringent criteria we had set. We then created a 13-point instrument to assess for bias and applied it on the primary studies that we intended to analyze.

RESULTS

Most primary studies are case series or case reports of patients undergoing abdominal hernia repair with biologic mesh, without any comparison group, and the inclusion of cases was only specified to be consecutive in 6 out of 40 cases. In terms of assessing outcomes, in none of the 40 articles were the outcome assessors blinded to the intervention or exposure status of participants.

CONCLUSION

The instrument that we created could allow to assess the risk of bias in different kind of studies. Our assessment of the studies based on the criteria that we had set up in the instrument clearly identified that further research needs to be done due to the lack of unbiased studies regarding the use of biologic meshes for abdominal hernia repair.

Biodegradable hyaluronan hydrogel coatings on acellular dermis grafts-A potential strategy to improve biologic graft durability in hernia repair application

Biologic grafts used in hernia repair undergo rapid cellular infiltration and remodeling, but their premature degradation often results in hernia recurrence. We hypothesize that a temporary barrier that prevents infiltration of acute inflammatory cells into the graft during the initial 4 weeks of implantation could mitigate graft degradation. The purpose of this study is to design tyramine-substituted hyaluronan (THA) hydrogel coatings with tunable degradation properties, as a means to develop a resorbable barrier for human acellular dermis grafts (HADM). THA plugs prepared at different cross-linking densities, by varying cross-linking agent concentration (0.0001-0.0075% H₂ O₂ ), demonstrated varying rates of in vitro degradation (25 U/mL hyaluronidase, 48 h). Based on these results, HADM grafts were coated with THA at three cross-linking densities (0.0001%, 0.00075%, and 0.003% H₂ O₂ ) and THA coating degradation was evaluated in vitro (25 U/mL hyaluronidase, 48 h) and in vivo (rat intraperitoneal implantation, 1-4 weeks). THA coatings degraded in vitro and in vivo with the lowest cross-linking density (0.0001% H₂ O₂ ), generally showing greater degradation as evidenced by significant decrease in coating cross-sectional area. However, all three coatings remained partially degraded after 4 weeks of in vivo implantation. Alternate strategies to accelerate in vivo degradation of THA coatings are required to allow investigation of the study hypothesis. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B:2664-2672, 2019.

A Current Review of Long-Acting Resorbable Meshes in Abdominal Wall Reconstruction

Concern for chronic infection of a permanent synthetic material in contaminated and "high risk" ventral hernia repairs has led to the development and dissemination of slowly resorbable biosynthetic materials at a lower cost compared with biologic mesh counterparts. Here, we review the preclinical and clinical data available for each long-acting resorbable mesh, with a candid comparison to biologic and synthetic equivalents.

Fight or Flight: The Role of Staged Approaches to Complex Abdominal Wall Reconstruction

Surgeons' comfort with abdominal wall reconstruction techniques and use of prosthetic reinforcement in contaminated fields has made repair of complex hernias during concomitant procedures an attractive endeavor. Understanding the precarious nature of this practice, tenets of thoughtful patient selection, and principles of repair that mitigate morbidity can allow for an educated thought process when deciding whether or not to pursue concomitant abdominal wall reconstruction.

Incisions and reconstruction approaches for large sarcomas

Large intraabdominal, retroperitoneal, and abdominal wall sarcomas provide unique challenges in treatment due to their variable histology, potential considerable size at the time of diagnosis, and the ability to invade into critical structures. Historically, some of these tumors were considered inoperable if surgical access was limited or the consequential defect was unable to be closed primarily as reconstructive options were limited. Over time, there has been a greater understanding of the abdominal wall anatomy and mechanics, which has resulted in the development of new techniques to allow for sound oncologic resections and viable, durable options for abdominal wall reconstruction. Currently, intra-operative positioning and employment of a variety of abdominal and posterior trunk incisions have made more intraabdominal and retroperitoneal tumors accessible. Primary involvement or direct invasion of tumor into the abdominal wall is no longer prohibitive as utilization of advanced hernia repair techniques along with the application of vascularized tissue transfer have been shown to have the ability to repair large area defects involving multiple quadrants of the abdominal wall. Both local and distant free tissue transfer may be incorporated, depending on the size and location of the area needing reconstruction and what residual structures are remaining surrounding the resection bed. There is an emphasis on selecting the techniques that will be associated with the least amount of morbidity yet will restore and provide the appropriate structure and function necessary for the trunk. This review article summarizes both initial surgical incisional planning for the oncologic resection and a variety of repair options for the abdominal wall spanning the reconstructive ladder.

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.

A Current Review of Hybrid Meshes in Abdominal Wall Reconstruction

Complex abdominal wall defects remain a common problem, though there has been significant advancement in technique and biomaterials over the last decade. The newly developed hybrid meshes are targeted to address several shortcomings of other meshes. Specifically, the marriage of biosynthetic or biologic materials with permanent prosthetic material is designed so that each will counteract the other's negative attributes. There are reports of permanent meshes having been associated with chronic pain, stiffness, and inflammation. However, their utility in maintaining biomechanical strength, thus limiting recurrence, makes them of value. In hybrid meshes, biosynthetic or biologic materials are coupled with permanent prosthetics, potentially protecting them from exhibiting deleterious effects by promoting and hastening tissue ingrowth. The various hybrid meshes currently available and investigational data are reviewed.

Bioprosthetic Versus Synthetic Mesh: Analysis of Tissue Adherence and Revascularization in an Experimental Animal Model

Supplemental Digital Content is available in the text.

Background:

Both synthetic and bioprosthetic meshes play important roles in surgical procedures such as ventral hernia repair. Although sometimes used interchangeably, these devices have inherently different properties. We therefore sought to better understand how these materials interact with the host environment to optimize surgical techniques and to improve outcomes.

Methods:

Synthetic mesh (polypropylene, Prolene) or bioprosthetic mesh (acellular fetal/neonatal bovine dermis, SurgiMend) was implanted intraperitoneally into rats lateral to a ventral incision in a novel intra-abdominal implant model. Two variables were modified with each material: (1) tight or loose tissue apposition, altered by modifying suture placement; and (2) abdominal wall injury, altered by selective abrasion of the peritoneal lining. After 5 weeks, the meshes and abdominal wall were evaluated grossly and histologically. The analysis focused on the degree of inflammatory response, neovascularization, and mesh adherence to the surrounding tissues.

Results:

Synthetic mesh adhered to the abdominal wall and visceral organs, regardless of the degree of apposition or tissue injury, due to a foreign body–mediated inflammatory reaction. In areas of noninjured peritoneal lining, SurgiMend was adherent peri-suture. Neovascularization entered the mesh from these apposition points and spread outward. In areas of denuded peritoneal lining, the adherent and vascularized areas were significantly greater and not merely coincident with suture placement.

Conclusions:

The inflammatory and wound healing responses with bioprosthetic mesh seem fundamentally different from synthetic mesh. Understanding these differences may lead to varied outcomes in adherence and vascularization of the materials, and ultimately the efficacy of hernia repair. Additionally, these differences highlight the need for further basic research to optimize mesh selection for surgical technique.

Major Complex Abdominal Wall Repair in Contaminated Fields with Use of a Non-cross-linked Biologic Mesh: A Dual-Institutional Experience

Background

Data on the use of biologic mesh in abdominal wall repair in complex cases remain sparse. Aim of this study was to evaluate a non-cross-linked porcine acellular dermal matrix for repair of complex contaminated abdominal wall defects.

Methods

Retrospective observational cohort study of consecutive patients undergoing abdominal wall repair with use of Strattice™ Reconstructive Tissue Matrix (LifeCell Corporation, Oxford, UK) between January 2011 and February 2015 at two National Intestinal Failure Units.

Results

Eighty patients were identified. Indications for abdominal wall repair included enterocutaneous fistula takedown (n = 50), infected synthetic mesh removal (n = 9), restoration of continuity or creation of a stoma with concomitant ventral hernia repair (n = 12), and others (n = 9). The median defect area was 143.0 cm² (interquartile range or IQR 70.0–256.0 cm²). All had a grade III or IV hernia. Component separation technique (CST) was performed in 54 patients (68%). Complete fascial closure was not possible despite CST and biologic mesh-assisted traction (bridged repair) in 20 patients (25%). In-hospital mortality was 1%. Thirty-six patients (45%) developed a wound infection. None required mesh removal. Of 76 patients with a median clinical follow-up of 7 months (IQR 4–15) available for analysis, 10 patients (13%) developed a hernia recurrence, of whom 3 had undergone bridged repairs. Seven patients developed a postoperative (recurrent) fistula (9%).

Conclusion

Repair of challenging and contaminated abdominal wall defects can be done effectively with non-cross-linked biologic mesh and component separation technique without the need for mesh removal despite wound infections.

Single-center ventral hernia repair with porcine dermis collagen implant

INTRODUCTION

This study aims to evaluate the outcomes and utilization of porcine acellular dermal collagen implant (PADCI) during VHR at a large tertiary referral center.

METHODS

Records of 5485 patients who underwent VIHR from June 1995 to August 2014 were retrospectively reviewed to identify patients >18 years of age who had VIHR with PADCI reinforcement. Use of multiple mesh reinforcement products, inguinal hernias, and hiatal hernias were exclusion criteria. The primary outcome was hernia recurrence, and secondary outcomes were early complications and surgical site occurrences (SSOs). Uni- and multivariate analyses assessed risk factors for recurrence after PADCI reinforced VIHR.

RESULTS

There were 361 patients identified (54.5% female, mean age of 56.7 ± 12.5 years, and mean body mass index (BMI) of 33.0 ± 9.9 kg/m²). Hypertension (49.5%), diabetes (24.3%), and coronary artery disease (14.4%) were the most common comorbidities, as was active smoking (20.7%). Most were classified as American Association of Anesthesiologists (ASA) Class 3 (61.7%). Hernias were distributed across all grades of the ventral hernia working group (VHWG) grading system: grade I 93 (25.7%), grade II 51 (14.1%), grade III 113 (31.3%), and grade IV 6 (1.6%). Most VIHR were performed from an open approach (96.1%), and were frequently combined with concomitant surgical procedures (47.9%). Early postoperative complications (first 30 days) were reported in 39.0%, with 71 being SSO. Of the 19.7% of patients with SSO, there were 31 who required procedural intervention. After a mean follow-up of 71.5 ± 20.5 months, hernia recurrence was documented in 34.9% of patients. Age and male gender were predictors of recurrence on multivariate analysis.

CONCLUSION

To the best of our knowledge, this is the largest retrospective single institutional study evaluating PADCI to date. Hernias repaired with PADCI were frequently in patients undergoing concomitant operations. Reinforcement with PADCI may be considered a temporary closure, with a relatively high recurrence rate, especially among patients who are older, male, and undergo multiple explorations in a short perioperative period.

A Meta-analysis of Outcomes Using Acellular Dermal Matrix in Breast and Abdominal Wall Reconstructions: Event Rates and Risk Factors Predictive of Complications

BACKGROUND

The use of acellular dermal matrix (ADM) has gained acceptance in breast and abdominal wall reconstructions. Despite its extensive use, there is currently a wide variation of reported outcomes in the literature. This study definitively elucidates the outcome rates associated with ADM use in breast and abdominal wall surgeries and identifies risk factors predisposing to the development of complications.

METHODS

A literature search was conducted using the Medline database (PubMed, US National Library of Medicine) and the Cochrane Library. A total of 464 articles were identified, of which 53 were eligible for meta-analysis. The endpoints of interest were the incidences of seroma, cellulitis, infection, wound dehiscence, implant failure, and hernia. The effects of various risk factors such as smoking, radiation, chemotherapy, and diabetes on the development of complications were also evaluated.

RESULTS

A majority of the studies were retrospective (68.6%) with a mean follow-up of 16.8 months (SD ± 10.1 months) in the breast group and 14.2 months (SD ± 7.8 months) in the abdominal wall reconstructive group. The overall risks and complications were as follows: cellulitis, 5.1%; implant failure, 5.9%; seroma formation, 8%; wound dehiscence, 8.1%; wound infection, 16.1%; hernia, 27.6%; and abdominal bulging, 28.1%. Complication rates were further stratified separately for the breast and abdominal cohorts, and the data were reported. This provides additional information on the associated abdominal wall morbidity in patients undergoing autologous breast reconstruction in which mesh reinforcement was considered as closure of the abdominal wall donor site. Radiation resulted in a significant increase in the rates of cellulitis (P = 0.021), and chemotherapy was associated with a higher incidence of seroma (P = 0.014).

CONCLUSION

This study evaluates the overall complication rates associated with ADM use by conducting a meta-analysis of published data. This will offer physicians a single comprehensive source of information during informed consent discussions as well as an awareness of the risk factors predictive of complications.

Mesh materials and hernia repair

Hernia incidence has been observed since ancient time. Advancement in the medical textile industry came up with the variety of mesh materials to repair hernia, but none of them are without complications including recurrence of hernia. Therefore individuals once developed with the hernia could not lead a healthy and comfortable life. This drawn attention of surgeons, patients, researchers and industry to know the exact mechanism behind its development, complications and recurrence. Recent investigations highlighted the role of genetic factors and connective tissue disorders being the reason for the development of hernia apart from the abnormal pressure that is known to develop during other disease conditions. This review discusses different mesh materials, their advantages and disadvantages and their biological response after its implantation.

Assessment of Human Acellular Dermis Graft in Porcine Models for Ventral Hernia Repair

OBJECTIVE

Preclinical evaluation of hernia meshes is commonly performed in porcine models. We recently developed two surgically induced porcine hernia models-an incisional and an excisional model-that formed persistent hernias in the absence of graft repair. Herein, we investigate if these models will continue to form a hernia after graft repair.

MATERIALS AND METHODS

Ten pigs were used to create two hernia models-a 10-cm partial-thickness incisional defect (n = 5) and an 8 × 8-cm full-thickness excisional defect (n = 5). The defects were repaired using a 12 × 12-cm human acellular dermis graft placed in a preperitoneal/retrorectus sublay position and fixed using transfascial sutures. Postoperative management included the use of suction drainage for 1 week and an abdominal binder for 4 weeks in the more severe excisional model. Hernia development was assessed clinically, and hernia defect size and volume were measured using postoperative computed tomography (CT) imaging over 12 weeks. Radiographic inflation testing (2 L inflation), biaxial mechanical testing, and histological evaluation were also performed at 12 weeks.

RESULTS

All pigs with the excisional model, but none with the incisional model, developed a clinically relevant hernia. At the end of 12 weeks, the excisional model had a significantly greater hernia defect size (259 ± 51 cm² vs. 47 ± 16 cm²) and repair volume (865 ± 414 cm³ vs. 85 ± 52 cm³) compared with the incisional model. The excisional model also showed an order of magnitude greater increase in repair volume (280 cm³ vs. 47 cm³) compared with the incisional model upon 2 L inflation. Furthermore, the excisional model showed a trend of having higher dilatational strain at average biaxial load of 250 N and lower stiffness compared with the incisional model. The excisional model had a thin, hypercellular hernia sac spanning the defect, whereas the incisional model had a thick densely fibrotic scar bridging the defect.

CONCLUSION

The 8 × 8-cm excisional defect model, together with appropriate postoperative wound management, in the pig model is recommended for preclinical investigation of different grafts for hernia repair. Novel CT imaging and biomechanical testing methods are recommended to measure functional outcomes of hernia repair in preclinical models.

First human use of hybrid synthetic/biologic mesh in ventral hernia repair: a multicenter trial

BACKGROUND

Mesh options for reinforcement of ventral/incisional hernia (VIH) repair include synthetic or biologic materials. While each material has known advantages and disadvantages, little is understood about outcomes when these materials are used in combination. This multicenter study reports on the first human use of a novel synthetic/biologic hybrid mesh (Zenapro^® Hybrid Hernia Repair Device) for VIH repair.

METHODS

This prospective, multicenter post-market clinical trial enrolled consecutive adults who underwent elective VIH repair with hybrid mesh placed in the intraperitoneal or retromuscular/preperitoneal position. Patients were classified as Ventral Hernia Working Group (VHWG) grades 1-3 and had clean or clean-contaminated wounds. Outcomes of ventral and incisional hernia were compared using appropriate parametric tests.

RESULTS

In all, 63 patients underwent VIH repair with hybrid mesh. Most were females (54.0%), had a mean age of 54.8 ± 10.9 years and mean body mass index of 34.5 ± 7.8 kg/m², and classified as VHWG grade 2 (87.3%). Most defects were midline (92.1%) with a mean area of 106 ± 155 cm². Cases were commonly classified as clean (92.1%) and were performed laparoscopically (60.3%). Primary fascial closure was achieved in 82.5% with 28.2% requiring component separation. Mesh location was frequently intraperitoneal (69.8%). Overall, 39% of patients available for follow-up at 12 months suffered surgical site events, which were generally more frequent after incisional hernia repair. Of these, seroma (23.7%) was most common, but few (8.5%) required procedural intervention. Other surgical site events that required procedural intervention included hematoma (1.7%), wound dehiscence (1.7%), and surgical site infection (3.4%). Recurrence rate was 6.8% (95% CI 2.2-16.6%) at 12-months postoperatively.

CONCLUSION

Zenapro^® Hybrid Hernia Repair Device is safe and effective in VHWG grade 1-2 patients with clean wounds out to 12 months. Short-term outcomes and recurrence rate are acceptable. This hybrid mesh represents a novel option for reinforcement during VIH repair.

Incarcerated and eventrated abdominal wall hernia reconstruction with autologous double-layer dermal graft in the field of purulent peritonitis-A case report

•

This is the first applied autologous dermal graft for eventrated hernia in an emergency case.

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Terminal ileum and ascending colon were perforated into the hernia sac causing dirty operating field.

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It was impossible to close the 223 cm² gap with sutures, biological mesh was not available.

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Specially prepared grafts were applied to reconstruct the gap in a double- layer tension free fashion.

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No hernia recurrency was observed 8 months after the surgery.

Introduction

Double-layer dermal grafts are used for the management of complicated abdominal wall hernias in obese, high risk patients. The method has not yet been used in case of emergency in septic/dirty environment.

Case report

A 76-year old female patient (BMI 36.7 kg/m²) was admitted with mechanical bowel obstruction and sepsis caused by a third time recurred, incarcerated and eventrated abdominal wall hernia. During the emergency surgery perforation of the terminal ileum and the ascending colon was detected, along with a feculent peritonitis and extended abdominal wall necrosis. Extended right hemicolectomy and necrectomy of the abdominal wall were performed. The surgery resulted in an abdominal wall defect measuring 223 cm², for the management of which direct closure was not possible. Using a specific method, an autologous dermal graft was prepared from the redundant skin. The first dermal graft was placed under the abdominal wall with 5 cm overlap, and the second layer was placed onto the first layer with 3 cm overlap in a perforated fashion. The operating time was 250 min. No significant intra-abdominal pressure elevation was measured. No reoperation was performed. On the fifth postoperative day, the patient was mobilised. She was discharged in satisfactory general condition on the 18th postoperative day. There is no recurrent hernia 8 months after the surgery.

Discussion

Abdominal wall reconstruction was possible in a necrotic, purulent environment by using a de-epithelised autologous double layer dermal graft, without synthetic or biological graft implantation. The advantage of the procedure was cost-effectivity, and the disadvantage was that only in an obese patient is the sufficient quantity of dermal graft available.

Conclusion

A homogeneous internal and perforated outer dermal graft was suitable for bridging the abdominal gap in the case of an obese, high risk patient. Autologous dermal grafts can be a safe and feasible alternative to biological meshes in emergency abdominal wall surgeries. Evaluation of a case series can be the next cornerstone of the method described above.