Human acellular dermal matrix for ventral hernia repair reduces morbidity in transplant patients. Hernia. 2011;15:141-145. [PMID: 21072551 DOI: 10.1007/s10029-010-0748-y]

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.

Outcomes of Complex Abdominal Wall Reconstruction with Biologic Mesh in Patients with 8 Years of Follow-Up

BACKGROUND

While many studies evaluated outcomes of abdominal wall reconstruction with biologic mesh, long-term data is lacking. In this study, we sought to analyze the outcomes of complex AWR with biologic mesh in a robust cohort of patients with a mean follow up of 8 years.

METHODS

We conducted a longitudinal study of AWR patients from 2005 to 2019. Hernia recurrence was the primary outcome, and surgical site occurrence was the secondary outcome. Predictive/protective factors were identified using a Cox proportional hazards regression models.

RESULTS

We identified 109 consecutive patients who met the inclusion criteria. Patient's mean (± SD) age was 57.5 ± 11.8 years, mean body mass index was 30.7 ± 7.2 kg/m2, and mean follow-up time was 96.2 ± 15.9 months. Fifty-six percent had clean defects, 34% had clean-contaminated defects, and 10% had contaminated/infected defects. Patients had a mean defect size of 261 ± 199.6 cm2 and mean mesh size of 391.3 ± 160.2 cm2. Nineteen patients (17.4%) developed HR at the final follow-up date. Obesity was independently associated with a four-fold higher risk of HR (hazard ratio, 3.98; 95%CI, 1.34 to 14.60, p = 0.02). SSOs were identified in 24.8% of patients. A prior hernia repair was associated with a three-fold higher risk of SSOs (Odds ratio, 3.13; 95%CI, 1.10 to 8.94, p = 0.03). No patient developed mesh infection.

CONCLUSION

These longitudinal data demonstrate that complex AWR with biologic mesh provides long-term durable outcomes with acceptable HR and SSO rates despite high contamination levels, patients complexity, and large defect size.

Outcomes of Ventral Hernia Repair After Orthotopic Liver Transplant Using Component Separation and Onlay Biologic Mesh

INTRODUCTION

The management of ventral hernias (VHs) after orthotopic liver transplant (OLT) can be uniquely challenging because of immunosuppression coupled with large laparotomy size that can compromise the quality of the abdominal wall. The component separation with multipoint suture onlay acellular dermis fixation technique has proven to be effective in high-risk abdominal wall reconstructions. The goal of this study was to elucidate the factors that affect safety and efficacy of VH repair in post-OLT patients.

METHODS

A retrospective review of 345 patients who underwent repair of VH with compartment separation and onlay acellular dermal matrix reinforcement from a single surgeon from 2012 to 2020 was conducted. Of these, 27 patients were identified with a history of OLT and were stratified based on whether the defect was a initial or recurrent hernia repair. The majority of patients had a standard chevron incision (70%). Data abstraction was performed for preoperative risk factors, hernia characteristics, surgical site complications, and postoperative course including hernia recurrence.

RESULTS

A majority of cases in the study period were initial hernia repairs (59%) with no significant differences in the patient demographics and size of VH defects (190 ± 112.69 cm 2 ). Comorbidities were similar between the groups with the exception of a significantly higher baseline creatinine levels and higher history of smoking in the recurrent hernia repair group ( P < 0.05). Of the 27 cases, there were no demonstrable hernia recurrences noted and an overall 11% complication rate. Univariate analysis noted a statistically significant difference in surgical site complication rate ( P = 0.017), with the initial hernia repair group having the lowest rate of surgical site complications.

CONCLUSIONS

In complex post-OLT patients with large VH, modified component separation with onlay acellular mesh was shown to have acceptable medium-term results. Further studies investigating the factors leading to postoperative complications are necessary to reduce recurrence in this evolving patient population.

Acellular dermal matrix in reconstructive surgery: Applications, benefits, and cost

Modern tissue engineering has made substantial advancements that have revolutionized plastic surgery. Acellular dermal matrix (ADM) is an example that has gained considerable attention recently. ADM can be made from humans, bovines, or porcine tissues. ADM acts as a scaffold that incorporates into the recipient tissue. It is gradually infiltrated by fibroblasts and vascularized. Fortunately, many techniques have been used to remove cellular and antigenic components from ADM to minimize immune system rejection. ADM is made of collagen, fibronectin, elastin, laminin, glycosaminoglycans, and hyaluronic acid. It is used in critical wounds (e.g., diabetic wounds) to protect soft tissue and accelerate wound healing. It is also used in implant-based breast reconstruction surgery to improve aesthetic outcomes and reduce capsule contracture risk. ADM has also gained attention in abdominal and chest wall defects. Some studies have shown that ADM is associated with less erosion and infection in abdominal hernias than synthetic meshes. However, its higher cost prevents it from being commonly used in hernia repair. Also, using ADM in tendon repair (e.g., Achilles tendon) has been associated with increased stability and reduced rejection rate. Despite its advantages, ADM might result in complications such as hematoma, seroma, necrosis, and infection. Moreover, ADM is expensive, making it an unsuitable option for many patients. Finally, the literature on ADM is insufficient, and more research on the results of ADM usage in surgeries is needed. This article aims to review the literature regarding the application, Benefits, and costs of ADM in reconstructive surgery.

Comparison of outcomes of ventral hernia repair using different meshes: a systematic review and network meta-analysis

PURPOSE

We conducted a network meta-analysis to evaluate potential differences in patient outcomes when different meshes, especially biological meshes, were used for ventral hernia repair.

METHODS

PubMed, Embase, Cochrane Library, and Clinical Trials.gov databases were searched for studies comparing biological meshes with biological or synthetic meshes for ventral hernia repair. The outcomes were hernia recurrence rate, surgical site infection, and seroma. We performed a two-step network meta-analysis to investigate the outcomes of several biological meshes: non-cross-linked human acellular dermal matrix (NCHADM), non-cross-linked porcine ADM (NCPADM), non-cross-linked bovine ADM (NCBADM), cross-linked porcine ADM (CPADM), and porcine small intestinal submucosa (PSIS).

RESULTS

From 6304 publications, 23 studies involving 2603 patients were finally included. We found no differences between meshes in recurrence at 1-year follow-up and in surgical site infection rate. NCBADM was associated with the lowest recurrence rate and the lowest surgical site infection rate. NCHADM implantation was associated with the lowest rate of seroma. PSIS was associated with a higher risk of seroma than NCHADM (pooled risk ratio 3.89, 95% confidence interval 1.13-13.39) and NCPADM (RR 3.42, 95% CI 1.29-9.06).

CONCLUSIONS

Our network meta-analysis found no differences in recurrence rate or surgical site infection among different biological meshes. The incidence of postoperative seroma was higher with PSIS than with acellular dermal matrices. We observed large heterogeneity in the studies of ventral hernia repair using biological meshes, and, therefore, well-designed randomized clinical trials are needed.

Abdominal wall complications after kidney transplantation: A clinical review

Introduction

Abdominal wall complications are common after kidney transplantation, and although they have a minor impact on patient and graft survival, they increase the patient's morbidity and may have an impact on quality of life. Abdominal wall complications have an overall incidence of 7.7–21%.

Methods

This review will explore the natural history of abdominal wall complications in the kidney transplant setting, with a special focus on wound dehiscence and incisional herni, with a particular emphasis on risk factors, clinical characteristics, and treatment.

Results

Many patient‐related risk factors have been suggested, including older age, obesity, and smoking, but kidney transplant recipients have an additional risk related to the use of immunosuppression. Wound dehiscence usually does not require surgical intervention. However, for deep dehiscence involving the fascial layer with concomitant infection, surgical treatment and/or negative pressure wound therapy may be required.

Conclusions

Incisional hernia (IH) may affect 1.1–18% of kidney transplant recipients. Most patients require surgical treatment, either open or laparoscopic. Mesh repair is considered the gold standard for the treatment of IH, since it is associated with a low rate of postoperative complications and an acceptable rate of recurrence. Biologic mesh could be an attractive alternative in patients with graft exposition or infection.

Effect of Wound Contamination on Outcomes of Abdominal Wall Reconstruction Using Acellular Dermal Matrix: 14-Year Experience with More than 700 Patients

BACKGROUND

Patients with contaminated/dirty-infected defects are at high risk for postoperative complications after abdominal wall reconstruction (AWR). We evaluated outcomes of AWR using acellular dermal matrix (ADM) for mesh reinforcement and identified predictors of hernia recurrence (HR), surgical site occurrences (SSOs), and surgical site infections (SSIs).

STUDY DESIGN

We conducted a retrospective cohort study of patients who underwent AWR using ADM, from March 2005 to June 2019. Outcomes were compared between Centers for Disease Control and Prevention (CDC) wound classifications. The primary outcome measure was HR. Secondary outcomes were SSOs and SSIs.

RESULTS

We identified 725 AWRs using ADM that met the study criteria. Participants had a mean age of 60 ± 11.5 years, mean BMI of 31 ± 7 kg/m², and mean follow-up time of 42 ± 29 months. Three hundred two patients (41.6%) had clean defects, 322 patients (44.4%) had clean-contaminated defects, and 101 patients (13.9%) had contaminated/dirty-infected defects. Patients with contaminated/dirty-infected defects had an HR rate of 20.8%, SSO rate of 54.5%, and SSI rate of 23.8%. Multivariate logistic regression found that contaminated/dirty-infected defects were independent predictors of SSOs (OR 2.99; 95% CI 1.72-5.18; p < 0.0001) and SSIs (OR 2.32; 95% CI 1.27-4.25; p = 0.006), but not HR (OR 1.06; 95% CI 0.57-1.98; p = 0.859).

CONCLUSIONS

SSIs and SSOs increase as contamination levels rise, but the risk of HR does not. AWR with ADM provides safe and durable outcomes, even with increasing levels of contamination.

Reconstrucción de la pared abdominal en pacientes con inmunosupresión: experiencia en una institución de alta complejidad

Introducción. Los pacientes con inmunosupresión llevados a cirugía abdominal convencional tienen un mayor riesgo de desarrollar hernias incisionales en el posoperatorio, y cuando ellas ocurren, es necesario individualizar el procedimiento quirúrgico de elección, según las características anatómicas, fisiológicas y clínicas de cada paciente. Este estudio describe las características demográficas y clínicas de los pacientes con inmunosupresión, llevados a reconstrucción de la pared abdominal, y sus desenlaces después de 30 días del procedimiento quirúrgico. Métodos. Serie de casos de pacientes con inmunosupresión llevados a reconstrucción de la pared abdominal, en un centro especializado de cuarto nivel de complejidad. Se incluyeron pacientes mayores de 18 años, operados en el período de enero de 2016 a diciembre de 2019. Resultados. Se presenta una serie de 18 pacientes, cinco (27,7 %) con algún tipo de inmunosupresión primaria y 13 (72,2 %) con algún tipo de inmunosupresión secundaria. La edad promedio fue de 56 años, 11 (61 %) fueron mujeres, el peso promedio de los participantes fue de 73,3 kg. Se encontraron complicaciones en ocho pacientes (44,4 %). Dos pacientes requirieron manejo en la Unidad de Cuidados Intensivos, por un máximo de tres días. Ninguno de los pacientes presentó recidiva de la hernia ni mortalidad. Discusión. La reconstrucción de la pared abdominal en pacientes inmunosuprimidos representa un reto para cualquier equipo quirúrgico debido a las condiciones especiales de los pacientes y a las variables asociadas al procedimiento. Las tasas de recidiva y de complicaciones de este estudio, se asemejan a las descritas en la literatura.

Biologic mesh is non-inferior to synthetic mesh in CDC class 1 & 2 open abdominal wall reconstruction

BACKGROUND

Biologic mesh has historically been used in contaminated abdominal wall reconstructions (AWRs). No study has compared outcomes of biologic and synthetic in clean and clean-contaminated hernia ventral hernia repair.

METHODS

A prospective AWR database identified patients undergoing open, preperitoneal AWR with biologic mesh in CDC class 1 and 2 wounds. Using propensity score matching, a matched cohort of patients with synthetic mesh was created. The objective was to assess recurrence rates and postoperative complications.

RESULTS

Fifty-eight patients were matched in each group. Patient in the biologic group had higher rates of immunosuppression, history of transplantation, and inflammatory bowel disease (p ≤ 0.05). Operative variables were comparable for biologic vs synthetic, including defect size (230.5 ± 135.4 vs 268.7 ± 194.5 cm², p = 0.62), but the synthetic mesh group had larger meshes placed (575.6 ± 247.0 vs 898.8 ± 246.0 cm² p < 0.0001). Wound infections (15.5% vs 8.9%, p = 0.28) were equivalent, and recurrence rates (1.7% vs 3.4%, p = 1.00) were similar on follow up (19.3 ± 23.3 vs 23.3 ± 29.7 months, p = 0.56).

CONCLUSIONS

In matched, lower risk, complex AWR patients with large hernia defects, biologic and synthetic meshes have equal outcomes.

Length of stay and surgical site complications are not increased after elective incisional hernia in patients with a history of solid organ transplantation

BACKGROUND

The incidence of ventral hernia development after solid organ transplantation has been reported to be up to 30%. We aim to determine the impact of previous solid organ transplant on post-operative length of stay (LOS) and surgical site complications in elective ventral hernia repairs.

METHODS

A retrospective review of prospectively collected data from the Abdominal Core Health Quality Collaborative (ACHQC) was conducted to include all patients age 18 years or older who underwent elective incisional hernia repair. Those with and without a history of solid organ transplantation were compared. The primary outcome was in-hospital LOS. Secondary outcomes included 30-day surgical site infection (SSI) rate, 30-day surgical site occurrence requiring procedural intervention (SSOPI) rate, 30-day overall post-operative complications and recurrence. The association between transplant and the LOS was tested with a negative binomial regression model adjusted for the demographic characteristics, comorbidities and hernia characteristics in the model.

RESULTS

The population analyzed included 13,452 (98.79%) patients without a history of organ transplantation and 165 (1.21%) patients who had a history of organ transplantation. After adjusting for age, hernia width, BMI, gender, race, insurance type, ASA class, hypertension, dyspnea, OR time > 2 h, abdominal wall SSI history, recurrent hernia, operative approach the median LOS was not significantly different between patients with a history of solid organ transplant [2.8 (2.6, 2.9) days] and those without [2.6 days (2.2, 3.1)] (p = 0.5). The proportion of SSI (2.4% vs 4.04%; p = 0.42), SSOPI (4.2% vs 5.8%; p = 0.38) and recurrence (0.6% vs 0.4%, p = 0.51) was similar between both groups. Other remaining 30-day post-operative were negligible in our sample.

CONCLUSIONS

There were no significant differences in LOS or infection rates between patients with and without a history of solid organ transplantation despite known risks of immunosuppression and chronic steroid use. Therefore, although these patients have many classic risk factors for poor outcomes, the data suggest that their history of solid organ transplantation should not preclude them from surgery.

Characterization of Inflammatory and Fibrotic Aspects of Tissue Remodeling of Acellular Dermal Matrix in a Nonhuman Primate Model

Human acellular dermal matrices (hADMs) are applied in various soft tissue reconstructive surgeries as scaffolds to support tissue remodeling and regeneration. To evaluate the clinical efficacy of hADM implants, it is integral that the hADM does not induce a host chronic inflammatory response leading to fibrotic encapsulation of the implant. In this study, we characterized the inflammatory and fibrosis-related tissue remodeling response of 2 commercial hADM products (SimpliDerm and AlloDerm RTU) in a nonhuman primate model using histology and gene expression profiling.

METHODS

Eighteen African green monkeys with abdominal wall defects were applied to evaluate the performance of SimpliDerm and AlloDerm RTU implants (N = 3) at 2, 4, and 12-weeks post-implantation. Using histology and gene expression profiling, tissue responses such as implant integration, degradation, cell infiltration, immune response, neovascularization, and pro-fibrotic responses over time were evaluated.

RESULTS

SimpliDerm showed a lower initial inflammatory response and slower implant degradation rate than AlloDerm RTU evidenced by histomorphological analysis. These factors led to a more anti-inflammatory and pro-remodeling microenvironment within SimpliDerm, demonstrated by lower TNFα levels and lower expression levels of pro-fibrotic markers, and promoted tissue repair and regeneration by 3-months post-implantation.

CONCLUSIONS

Overall, histology and gene expression profiling analyses shown in this study demonstrated an effective model for analyzing hADM performance in terms of host inflammatory and fibrotic response. Further studies are warranted to fully evaluate the utility of this novel hADM in the clinical setting and verify the prognosis of our pre-clinical analysis model.

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.

Incisional Hernia Repairs after Abdominal Organ Transplantation

Incisional hernias occur after abdominal organ transplantation with rates of 1.6 per cent to 18 per cent in kidney transplants (KTs) and 1.7 to 32.4 per cent in liver transplants (LTs). We hypothesized a difference in KTand LToutcomes in patients with and without repair of incisional hernias. We conducted a retrospective cohort study of abdominal transplants from 2012 through 2016. The difference across compared groups for continuous variables was assessed using the independent sample t test, and for binary variables, using the chi-squared test. A total of 1518 transplants were performed, including 1138 KTs and 380 LTs. There were 83 KT incisional hernias (67 repaired) and 59 LT incisional hernias (48 repaired). There was no difference between groups with regard to smoking, diabetes, age, BMI, days on dialysis (KTs), pretransplant Model for End-Stage Liver Disease (MELD) (LTs), cold ischemic time, graft survival, or recurrence rate by repair method. In the LT population, there was a statistically significant difference in days on the waitlist ( P = 0.02), drain placement ( P = 0.04), and cytomegalovirus (CMV) mismatch ( P = 0.02). Patient survival was also statistically significant for KTs ( P = 0.04) and LTs ( P = 0.01). KT and LT patients who have their incisional hernias repaired have better overall survival, regardless of the repair technique.

Utility of a modified components separation for abdominal wall reconstruction in the liver and kidney transplant population

Background

Incisional hernia is a common complication following visceral organ transplantation. Transplant patients are at increased risk of primary and recurrent hernias due to chronic immune suppression and large incisions. We conducted a retrospective review of patients with a history of liver or kidney transplantation who underwent hernia repair to analyze outcomes and hernia recurrence.

Methods

This is a single center, retrospective review of 19 patients who received kidney and/or liver transplantation prior to presenting with an incisional hernia from 2011 to 2017. All hernias were repaired with open component separation technique (CST) with biologic mesh underlay.

Results

The mean age of patients was 61.0±8.3 years old, with a mean body mass index of 28.4±4.8 kg/m², 15 males (78.9%), and four females (21.1%). There were seven kidney, 11 liver, and one combined liver and kidney transplant patients. The most common comorbidities were hypertension (16 patients, 84.2%), diabetes (9 patients, 47.4%), and tobacco use (8 patients, 42.1%). Complications occurred in six patients (31.6%) including hematoma (1/19), abscess (1/19), seroma (2/19), and hernia recurrence (3/19) at mean follow-up of 28.7±22.8 months. With the exception of two patients with incomplete follow-up, all patients healed at a median time of 27 days.

Conclusions

This small, retrospective series of complex open CST in transplant patients shows acceptable rates of long-term hernia recurrence and healing. By using a multidisciplinary approach for abdominal wall reconstruction, we believe that modified open CST with biologic mesh is a safe and effective technique in the transplant population with complex abdominal hernias.

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.

Effectiveness and versatility of biological prosthesis in transplanted patients

AIM

To emphasize the effectiveness and versatility of prosthesis, and good tolerance by patients with incisional hernia (IH).

METHODS

From December 2001 to February 2016, 270 liver transplantations were performed at San Camillo Hospital. IH occurred in 78 patients (28.8%). IH usually appeared early within the first year post-orthotopic liver transplantation. In the first era, fascial defect was repaired by primary closure for defects smaller than 2.5 cm or with synthetic mesh for greater defects. Recently, we started using biological mesh (Permacol™, Covidien). We present a series of five transplanted patients submitted to surgery for abdominal wall defect correction repaired with biological mesh (Permacol™, Covidien).

RESULTS

In our cases, the use of biological prosthesis (Permacol™, Covidien) have proven to be effective and versatile in repairing hernia defects of different kinds; patients did not suffer infections of the prosthesis and no recurrence was observed. Furthermore, the prosthesis remains intact even in the years after surgery.

CONCLUSION

The cases that we presented show that the use of biological mesh (Permacol™, Covidien) in transplanted patients may be safe and effective, being careful in the management of perioperative immunosuppression and renal and graft function, although the cost of the product itself has been the main limiting factor and there is need for prospective studies for further evaluations.

Long-Term Outcomes after Abdominal Wall Reconstruction with Acellular Dermal Matrix

BACKGROUND

Long-term outcomes data for hernia recurrence rates after abdominal wall reconstruction (AWR) with acellular dermal matrix (ADM) are lacking. The aim of this study was to assess the long-term durability of AWR using ADM.

STUDY DESIGN

We studied patients who underwent AWR with ADM at a single center in 2005 to 2015 with a minimum follow-up of 36 months. Hernia recurrence was the primary end point and surgical site occurrence (SSO) was a secondary end point. The recurrence-free survival curves were estimated by Kaplan-Meier product limit method. Univariate and multivariable Cox proportional hazards regression models and logistic regression models were used to evaluate the associations of risk factors at surgery with subsequent risks for hernia recurrence and SSO, respectively.

RESULTS

A total of 512 patients underwent AWR with ADM. After excluding those with follow-up less than 36 months, 191 patients were included, with a median follow-up of 52.9 months (range 36 to 104 months). Twenty-six of 191 patients had a hernia recurrence documented in the study. The cumulative recurrence rates were 11.5% at 3 years and 14.6% by 5 years. Factors significantly predictive of hernia recurrence developing included bridged repair, wound skin dehiscence, use of human cadaveric ADM, and coronary disease; component separation was protective. In a subset analysis excluding bridged repairs and human cadaveric ADM patients, cumulative hernia recurrence rates were 6.4% by 3 years and 8.3% by 5 years. The crude rate of SSO was 25.1% (48 of 191). Factors significantly predictive of the incidence of SSO included at least 1 comorbidity, BMI ≥30 kg/m², and defect width >15 cm.

CONCLUSIONS

Use of ADM for AWR was associated with 11.5% and 14.6% hernia recurrence rates at 3- and 5-years follow-up, respectively. Avoiding bridged repairs and human cadaveric ADM can improve long-term AWR outcomes using ADM.

Chemotherapy does not adversely impact outcome following post-incisional hernia repair with biomaterial mesh

Background

Patients receiving chemotherapy are at increased risk for developing recurrent or post‐incisional hernias (PIH). Biological materials are an alternative to synthetic mesh in contaminated fields. The impact of chemotherapy on biomaterial tissue ingrowth and integration has not been well studied.

Methods

From 2008 to 2011 patients who underwent PIH repair with biomaterial mesh (Biodesign®) were selected. Patients were divided into two groups: those receiving chemotherapy (CT) and those not receiving chemotherapy (NCT).

Results

Forty‐five patients were identified, 28 (62%) in the NCT group and 17 (38%) in the CT group. Median follow up for NCT and CT groups were 27 and 17 months, respectively. A total of 9/45 (20%) surgical site infections (SSI) were diagnosed, with 6/28 (21%) in the NCT and 3/17 (18%) in the CT group (P = 0.53). Seroma formation was seen in 5/28 (18%) of NCT patients and 4/17 (23%) in CT group (P = 0.46). Overall hernia recurrence rate was 22%, and the rates of recurrence were similar among the CT 3/17 (18%) and NCT 7/28 (25%) groups (P = 0.42).

Conclusion

The use of perioperative chemotherapy did not increase the rate of wound complications following PIH repair with biologic mesh in this group of patients. J. Surg. Oncol. 2015 111:725–728. © 2015 The Authors. Journal of Surgical Oncology Published by Wiley Periodicals, Inc.

Effectiveness of porcine dermal collagen in giant hernia closure in patients with deleterious fascia constitution after orthotopic liver transplantation

Incisional hernias (IHs) occur universally after orthotopic liver transplantation (OLT). This study aimed to investigate the effectiveness of porcine dermal collagen (PDC) as a closing aid in giant hernias after OLT in a prospective trial. If direct closure (DC) was not feasible due to the hernia size and abdominal wall constitution, a PDC mesh was implanted. All patients from the PDC and DC groups were followed prospectively for 24 months. IH recurrence rates served as the primary endpoint, and the development of infections and wound healing disorders served as the secondary endpoints. Recurrence rate was 21% (4/19) in DC patients and 12% (2/16) in PDC patients (P = 0.045). Implant site infections occurred in five of PDC and one of DC patients (P < 0.05). All of them were managed with antibiotics; two of the PDC patients required surgical drainage. Histological analysis of PDC mesh biopsies indicated good angiogenesis and integration of the PDC into the abdominal wall. PDC was effective in our study for incisional hernia repair, and our results compared favourably with those of patients in whom direct hernia closure was feasible.

Biologic versus nonbiologic mesh in ventral hernia repair: a systematic review and meta-analysis

BACKGROUND

The current standard of treatment for most ventral hernias is a mesh-based repair. Little is known about the safety and efficacy of biologic versus nonbiologic grafts. A meta-analysis was performed to examine two primary outcomes: recurrence and wound complication rates.

METHODS

Electronic databases and reference lists of relevant articles were systematically searched for all clinical trials and cohort studies published between January 1990 and January 2012. A total of eight retrospective studies, with 1,229 patients, were included in the final analysis.

RESULTS

Biologic grafts had significantly fewer infectious wound complications (p < 0.00001). However, the recurrence rates of biologic and nonbiologic mesh were not different. In subgroup analysis, there was no difference in recurrence rates and wound complications between human-derived and porcine-derived biologic grafts.

CONCLUSIONS

Use of biologic mesh for ventral hernia repair results in less infectious wound complications but similar recurrence rates compared to nonbiologic mesh. This supports the application of biologic mesh for ventral hernia repair in high-risk patients or patients with a previous history of wound infection only when the significant additional cost of these materials can be justified and synthetic mesh is considered inappropriate.

Outcomes of abdominal wall reconstruction with acellular dermal matrix are not affected by wound contamination

BACKGROUND

The optimal type of mesh for complex abdominal wall reconstruction has not been elucidated. We hypothesized that AWRs using acellular dermal matrix (ADM) experience low rates of surgical site occurrence (SSO) and surgical site infection, despite increasing degrees of wound contamination.

STUDY DESIGN

We retrospectively reviewed prospectively collected data from consecutive abdominal wall reconstructions with ADM over a 9-year period. Outcomes of abdominal wall reconstructions were compared between patients with different CDC wound classifications. Univariate and multivariate logistic regression and Cox proportional hazard regression analyses identified potential associations and predictive/protective factors.

RESULTS

The 359 patients had a mean follow-up of 28.3 ± 19.0 months. Reconstruction of clean wounds (n = 171) required fewer reoperations than that of combined contaminated (n = 188) wounds (2.3% vs 11.2%; p = 0.001) and trended toward experiencing fewer SSOs (19.9% vs 28.7%, p = 0.052). There were no significant differences between clean and combined contaminated cases in 30-day SSI (8.8% vs 8.0%), hernia recurrence (9.9% vs 10.1%), and mesh removal (1.2% vs 1.1%) rates. Independent predictors of SSO included body mass index ≥30 kg/m(2) (odds ratio [OR] 3.6; p < 0.001), 1 or more comorbidities (OR 2.5; p = 0.008), and defect width ≥15 cm (OR 1.8; p = 0.02).

CONCLUSIONS

Complex abdominal wall reconstructions using ADM demonstrated similar rates of complications between the different CDC wound classifications. This is in contradistinction to published outcomes for abdominal wall reconstruction using synthetic mesh that show progressively higher complication rates with increasing degrees of contamination. These data support the use of ADM rather than synthetic mesh for complex abdominal wall reconstruction in the setting of wound contamination.

Intrahepatic cholangiocarcinoma in a transplant liver--selective internal radiation therapy followed by right hemihepatectomy: report of a case

Intra- or extrahepatic cholangiocarcinomas are the second most common primary liver malignancies behind hepatocellular carcinoma. Whereas the incidence for intrahepatic cholangiocarcinoma is rising, the occurrence of extrahepatic cholangiocarcinoma is trending downwards. The treatment of choice for intrahepatic cholangiocarcinoma remains liver resection. However, a case of liver resection after selective internal radiation therapy in order to treat a recurrent intrahepatic cholangiocarcinoma in a transplant liver is unknown in the literature so far. Herein, we present a case of a patient undergoing liver transplantation for Wilson’s disease with an accidental finding of an intrahepatic cholangiocarcinoma within the explanted liver. Due to a recurrent intrahepatic cholangiocarcinoma after liver transplantation, a selective internal radiation therapy with yttrium-90 microspheres was performed followed by right hemihepatectomy. Four years later, the patient is tumor-free and in a healthy condition.

Complex ventral hernia repair with a human acellular dermal matrix

Purpose

The ideal approach to complex ventral hernia repair is frequently debated. Differences in processing techniques among biologic materials may impact hernia repair outcomes. This study evaluates the outcomes of hernia repair with a terminally sterilized human acellular dermal matrix (TS-HADM) (AlloMax^® Surgical Graft, by C. R. Bard/Davol, Inc., Warwick, RI, USA) treated with low-dose gamma irradiation.

Methods

A single-arm multi-center retrospective observational study of patients undergoing hernia repair with TS-HADM was performed. Data analyses were exploratory only; no formal hypothesis testing was pre-specified.

Results

Seventy-eight patients (43F, 35M) underwent incisional hernia repair with a TS-HADM. Mean follow-up was 20.5 months. Preoperative characteristics include age of 56.6 ± 11.1 years, BMI 36.7 ± 9.9 kg/m², and mean hernia defect size 187 cm². Sixty-five patients underwent component separation technique (CST) with a reinforcing graft. Overall, 21.8 % developed recurrences. Recurrences occurred in 15 % of patients repaired with CST. Major wound complications occurred in 31 % of patients overall. Based upon CDC surgical wound classification, major wound complications were seen in 26, 40, 56, and 50 % of Class 1, 2, 3, and 4 wounds, respectively. No grafts required removal.

Conclusions

Hernia recurrences are not uncommon following complex abdominal wall reconstruction. Improved outcomes are seen when a TS-HADM is utilized as reinforcement to primary fascial closure.

Strategies for the management of adverse events associated with mTOR inhibitors

Mammalian target of rapamycin (mTOR) inhibitors are used as potent immunosuppressive agents in solid-organ transplant recipients (everolimus and sirolimus) and as antineoplastic therapies for various cancers (eg, advanced renal cell carcinoma; everolimus, temsirolimus, ridaforolimus). Relevant literature, obtained from specific PubMed searches, was reviewed to evaluate the incidence and mechanistic features of specific adverse events (AEs) associated with mTOR inhibitor treatment, and to present strategies to effectively manage these events. The AEs examined in this review include stomatitis and other cutaneous AEs, wound-healing complications (eg, lymphocele, incisional hernia), diabetes/hyperglycemia, dyslipidemia, proteinuria, nephrotoxicity, delayed graft function, pneumonitis, anemia, hypertension, gonadal dysfunction, and ovarian toxicity. Strategies for selecting appropriate patients for mTOR inhibitor therapy and minimizing the risks of AEs are discussed, along with best practices for identifying and managing side effects. mTOR inhibitors are promising therapeutic options in immunosuppression and oncology; most AEs can be effectively detected and managed or reversed with careful monitoring and appropriate interventions.

Fascia lata allografts as biological mesh in abdominal wall repair: preliminary outcomes from a retrospective case series

BACKGROUND

The use of biological meshes in management of infected abdominal hernias or in abdominal fields at high risk of infection (potentially contaminated or with relevant comorbidities) is well established. Available products include xenogenic patches or decellularized dermal allografts. Despite their biomechanical features, banked fascial allografts have not been investigated yet in this setting. The authors evaluated the safety and effectiveness of banked fascia lata allografts as biological meshes in abdominal wall repair.

METHODS

A consecutive series of patients affected by abdominal wall defects and who were candidates for repair by means of a biological mesh and treated in the authors' institution with banked fascia lata allografts were reviewed retrospectively. Data from clinical and instrumental follow-up evaluations up to 48 months (average, 23 months) were analyzed.

RESULTS

Twenty-one patients (aged 1 to 86 years) with abdominal wall defects resulting from traumatic (n = 1), neoplastic (n = 6), or multiple previous laparotomies (n = 14) were treated from January of 2008 to October of 2012. Operations had no relevant postoperative complications. At clinical/instrumental follow-up examinations, no major signs of recurrence, laxity, infection of grafts, or other related pathologic symptoms were recorded. Three patients suffered from temporary minor complications (e.g., wound seroma, partial cutaneous dehiscence). At instrumental (computed tomographic scan or magnetic resonance imaging) evaluations, the neofascial tissue appeared stable until medium-term follow-up (3 to 6 months), later being gradually degraded and apparently replaced by host tissue.

CONCLUSION

According to limited preliminary outcomes, banked fascia lata allografts seem to provide a biocompatible, safe, and effective alternative to other biological meshes.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

A modified approach to component separation using biologic graft as a load-sharing onlay reinforcement for the repair of complex ventral hernia

BACKGROUND

Components separation has been proposed as a means to close large ventral hernia without undue tension. We report a modification on open components separation that allows for the incorporation of onlaid noncrosslinked porcine acellular dermal matrix (Strattice, LifeCell Corp, Branchburg, NJ) as a load-sharing structure.

METHODS

This was a retrospective case series including all cases using Strattice from July 2008 through December 2009. Data evaluated included patient demographics, comorbidities associated with risk of recurrence, hernia grade, and postoperative complications. The primary outcomes were hernia recurrence and surgical site occurrences.

RESULTS

There were 58 patients; 60.8% presented with a recurrent incisional hernia. Average length of follow-up was 384 days. There were 4 hernia recurrences (7.9%). Complications included surgical site infection (20.7%), seroma (15.5%), and hematoma (5%) requiring intervention. Four deaths occurred in the series due to causes unrelated to the hernia repair, only 1 within 30 days of operation.

CONCLUSIONS

This series demonstrates that components separation reinforced with noncrosslinked porcine acellular dermal matrix onlay is an efficacious, single-stage repair with a low rate of recurrence and surgical site occurrences.

Short-term in vivo biological and mechanical remodeling of porcine acellular dermal matrices

The purpose of this study was to assess the biological revitalization and mechanical integrity of Strattice^™ Reconstructive Tissue Matrix, a porcine-derived acellular dermal matrix, in vivo over time. We expanded the traditional subcutaneous model to incorporate biologic matrix scaffolds large enough to allow evaluation of mechanical properties in addition to the assessment of histological changes. Hematoxylin and eosin histology staining was used to evaluate cellular and tissue changes, and a mechanical testing frame was used to measure the ultimate tensile stress and Young’s modulus of the implanted material over time. Cell infiltration and blood vessel formation into the porcine-derived acellular dermal matrix were evident at 2 weeks and increased with implantation time. Mechanical remodeling resulted in an initial decrease in ultimate tensile stress, not associated with cell infiltration, followed by a significant increase in material strength, concurrent with histological evidence of new collagen synthesis. Young’s modulus followed a similar trend.

Abdominal wall defect repair with biological prosthesis in transplanted patients: single center retrospective analysis and review of the literature

The risk of fascial dehiscence, wound infection and incisional hernias in organ recipients is higher. Retrospective analysis of our departments database, checking the last 12 years (2000-2012), and of the literature (1966-2012) were conducted. In our database we found seven patients: five liver (71.4 %), one kidney (14.3 %), one multivisceral (14.3 %); five males (71.4 %), two females (28.6 %). Five (71.4 %) were operated in urgency setting and two in ordinary setting (28.6 %). The mean/median number of laparotomies before the incisional hernia is of 2.1/1 (range 1-5). In five patients swine intestinal submucosa (71.4 %) have been used and in two porcine dermal collagen (28.6 %). The mean/median age was 48.3/52 years (range 18-61). The mean/median body mass index was 26.7/27 (range 19-34). The mean/median for follow-up after intervention was 40.1/33 months (range 50-21). Recurrence rate was 14.3 %. Complication rate was 28.6 %. Adding the present report, the literature reports 70 cases. 20 % of prosthesis have been implanted inlay, 25.7 % underlay, in 5.7 % intraperitoneal and in 48.6 % were not specified. The mean age ranges from 0.7 to 48.3 years. Kidney, liver, pancreas, bowel and multivisceral transplant are reported. Porcine dermal collagen has been implanted in 24.3 %, human dermal collagen in 51.4 % and swine intestinal submucosa in 24.3 %. The immunosuppression regimens comprehend variable associations of tacrolimus, steroids, mycophenolate mofetil, sirolimus, thymoglobulin, azathioprine/basiliximab and daclizumab. The mean follow-up is 16.2 months. The mean complication rate is 9.4 %. Biological prosthesis seems to be useful and safe in abdominal wall repair surgery in transplanted patients.

Complications of acellular dermal matrices in abdominal wall reconstruction

BACKGROUND

Acellular dermal matrices have been increasingly used in abdominal wall reconstruction. Unique characteristics of these grafts have allowed surgeons to reconstruct increasingly complex abdominal wall defects. This has resulted in a myriad of complications related to the acellular dermal matrix with unique management strategies as compared with synthetic mesh.

METHODS

A review of the literature was performed to identify studies evaluating the use and efficacy of acellular dermal matrices in abdominal wall reconstruction. Complication profiles were identified and are compared. Differences between porcine and human derivatives were identified.

RESULTS

Hernia recurrence, infection, skin necrosis, and fluid collections were among the most common complications following abdominal wall reconstruction identified in the literature. Differences among various acellular dermal matrix products make certain types more suitable for abdominal wall reconstruction.

CONCLUSIONS

Complications are frequent in abdominal wall reconstruction. Many acellular dermal matrices have properties that allow for conservative management and maintenance of reconstruction when complications occur. With traditional synthetic mesh reconstruction, complications likely result in mesh explantation and prolonged morbidity. With acellular dermal matrix reconstruction, however, more conservative treatment strategies will allow for mesh salvage.

Acellular dermal matrices in abdominal wall reconstruction: a systematic review of the current evidence

BACKGROUND

Reconstruction of the anterior abdominal wall is a complex procedure that can be complicated by contamination, loss of domain, previous scarring or radiotherapy, and reduced availability of local tissues. With the introduction of acellular dermal matrices to clinical use, it was hoped that many of the problems associated with previous synthetic materials could be overcome. With their enhanced biocompatibility, acellular dermal matrices are believed to integrate with surrounding tissues while demonstrating resistance to infection, extrusion, erosion, and adhesion formation.

METHODS

The MEDLINE database was reviewed, including all publications as of December 31, 2011, using the search terms "dermal matrix" or "human dermis" or "porcine dermis" or "bovine dermis," applying the limits "human" and "English language." Prospective and retrospective clinical articles were identified.

RESULTS

A total of 40 eligible articles were identified and included in this review. Thirty-five of the studies were level IV; the remaining studies were level III. Acellular dermal matrix was used to reconstruct the abdominal wall in a wide range of clinical settings, including trauma, tumor resection, sepsis, and hernia repairs. The operative methods varied widely among clinical studies. While the heterogeneity of the patient populations and techniques limited interpretation of the data, concerns were identified regarding high rates of hernia recurrence with acellular dermal matrix use.

CONCLUSION

High-quality data derived from level I, II, and III studies are necessary to determine the indications for acellular dermal matrix use and the optimal surgical techniques to maximize outcomes in abdominal wall reconstruction.

A decade of ventral incisional hernia repairs with biologic acellular dermal matrix: what have we learned?

BACKGROUND

Innovative types of biologic mesh have provided new alternatives to ventral incisional hernia repair, especially in the face of contamination. The authors studied the experience and outcomes of patients who underwent repair of a ventral incisional hernia with biologic mesh.

METHODS

Online database and detailed reference searches were conducted. Studies chosen for review had a sample size of at least 40 patients, level IV evidence at most, and a Methodological Index for Nonrandomized Studies index of at least 10. Indications for use of biologic mesh, type of mesh, patient comorbidities, and surgical techniques were also noted.

RESULTS

Eight studies fulfilled the search criteria and included 635 patients using AlloDerm, Surgisis, and Strattice biologic tissue matrices. In one study, indications and surgical techniques were standardized, and follow-up was prospective. In the other seven studies, indications, surgical techniques, and follow-up were assessed retrospectively. The mean patient age, when reported, was 55.7 years. Body mass index ranged from 30 to 35 kg/m2 in 44 percent of the reported patients. In seven of the eight studies [565 patients (89 percent)], the mean follow-up was 25.8 months and the mean hernia recurrence rate was 21 percent. Complication rate exceeded 20 percent in most studies.

CONCLUSIONS

Biologic tissue matrices are mostly used in contaminated fields, which has allowed for a one-stage repair with no or little subsequent mesh removal. Ventral incisional hernia repair with these matrices continues to be plagued by a high recurrence rate and complications. Prospective randomized trials are needed to properly direct practice in the use of these meshes and evaluate their ultimate value.

Repair of incisional hernias with biological prosthesis: a systematic review of current evidence

BACKGROUND

No consensus has been reached on the use of bioprosthetics to repair abdominal wall defects. The purpose of this systematic review was to summarize the outcomes from studies describing this use of various bioprosthetics for incisional hernia repair.

METHODS

Studies published by October 2011 were identified through literature searches using EMBASE, MEDLINE, and the Cochrane Central Register of Controlled Trials.

RESULTS

A total of 491 articles were scanned, 60 met eligibility criteria. Most studies were retrospective case studies. The studies ranged considerably in methodologic quality, with a modified Methodological Index of Nonrandomized Studies score from 5 to 12. Many repairs were performed in contaminated surgical sites (47.9%). At least one complication was seen in 87% of repairs. Major complications noted were wound infections (16.9%) and seroma (12.0%). With a mean follow-up period of 13.6 months the hernia recurrence rate was 15.2%.

CONCLUSIONS

There is an insufficient level of high-quality evidence in the literature on the value of bioprosthetics for incisional hernia repair. Randomized controlled trials that use standardized reporting comparing bioprosthetics with synthetic mesh for incisional hernia repair are needed.

Enterocutaneous fistulas and a hostile abdomen: reoperative surgical approaches

Damage-control surgery and open-abdomen is an acceptable—and often lifesaving—approach to the treatment of patients with severe trauma, abdominal compartment syndrome, necrotizing soft tissue catastrophes, and other abdominal disasters, when closing the abdomen is not possible, ill advised, or will have serious sequelae. However, common consequences of open-abdomen management include large abdominal wall defects, enterocutaneous fistulas (ECFs), and enteroatmospheric fistulas (EAFs). Furthermore, in such patients, a frozen and hostile abdomen (alone or combined with ECFs) is not uncommon. Adding biologic mesh to our surgical armamentarium has revolutionized hernia surgery.

Biological meshes: a review of their use in abdominal wall hernia repairs

PURPOSE

Biological meshes are mostly used in infected fields within complex abdominal wall hernia repairs. There is no consensus, however, on the most appropriate material to be used in a given situation.

METHODS

A literature review of published articles reporting the utilization of biological meshes in ventral/incisional hernia repair was conducted. Data were analyzed to compare the recurrence rates obtained with biological meshes.

MAIN FINDINGS

Only a few prospective comparative studies were identified. Most publications relate to AlloDerm®, Permacol™ and Surgisis™ with data from other meshes insufficient to draw conclusions. AlloDerm has a 0-100% recurrence rate among studies. It compares poorly with Surgisis and results in an unfavorable outcome when used as a 'bridge prosthesis'. Permacol has consistent recurrence rates of 0-15%, whatever the patients' profiles or the context of infected fields, when considering the most relevant studies. The Surgisis results are more conflicting: the mesh exhibits low recurrence rates in clean fields, but in infected fields the recurrence rate is up to 39%.

CONCLUSION

Taken together, these studies suggest that the cross-linked mesh, Permacol has the lowest failure rate and the longest time to failure, particularly in contaminated or infected fields. However, this data should be confirmed by large prospective randomized studies.

Engineered whole organs and complex tissues

End-stage organ failure is a key challenge for the medical community because of the ageing population and the severe shortage of suitable donor organs available. Equally, injuries to or congenital absence of complex tissues such as the trachea, oesophagus, or skeletal muscle have few therapeutic options. A new approach to treatment involves the use of three-dimensional biological scaffolds made of allogeneic or xenogeneic extracellular matrix derived from non-autologous sources. These scaffolds can act as an inductive template for functional tissue and organ reconstruction after recellularisation with autologous stem cells or differentiated cells. Such an approach has been used successfully for the repair and reconstruction of several complex tissues such as trachea, oesophagus, and skeletal muscle in animal models and human beings, and, guided by appropriate scientific and ethical oversight, could serve as a platform for the engineering of whole organs and other tissues.

Solid organ procurement from donors with carbon monoxide poisoning and/or burn--a systematic review

INTRODUCTION

Traditionally, carbon monoxide poisoning and/or burn are considered contraindications to organ procurement. Previously reported cases have shown mixed results and many have been redundantly reported in the literature.

METHODS

We performed a systematic review of all reported cases of organ transplantation procured from donors with carbon monoxide poisoning and/or burn to investigate whether these patients are suitable donors for solid organ transplantations.

RESULTS

Organ survival rates of reported organs were high (86%). All organs procured from donors with carbon monoxide poisoning and burn survived during follow-up. Mean donors' peak carbon monoxide levels were comparable for organs surviving or failing during follow-up (31 ± 2.7 vs. 29 ± 26.8; p=0.95). Eighty-seven per cent of organs procured from donors supported with inotropes or vasopressors prior to organ procurement and 91% of organs procured from donors who were cardiopulmonary resuscitated prior to organ procurement survived during follow-up.

CONCLUSIONS

Burn, carbon monoxide poisoning, high peak carbon monoxide-levels, use of inotropes or vasopressors or cardiopulmonary resuscitation prior to procurement are not contraindications for organ procurement and transplantation. New guidelines for burn units defining the special requirements for organ procurement from donors with carbon monoxide poisoning and/or burn are needed to raise the awareness for potential organ donors and to ultimately increase the donor pool and save patients' lives.