Biologic grafts for ventral hernia repair: a systematic review. Am J Surg. 2013;205:220-230. [PMID: 23200988 DOI: 10.1016/j.amjsurg.2012.05.028]

Xenograft biologic mesh in parietal and general surgery: Technical assessment and review of clinical effectiveness and safety data

STUDY AIM

To describe the main technical characteristics of biologic prostheses used for parietal reinforcement and to present the state of the art on their risk/benefit ratio.

METHODS

We conducted a technical analysis of manufacturer specifications of the biologic prostheses that are currently available in France accompanied by a literature review by selecting meta-analyses and systematic reviews, randomized controlled trials and publications of health technology rating agencies.

RESULTS

Biological implants for parietal reinforcement are mainly intended for use in a contaminated environment where the use of synthetic prostheses is contra-indicated. We identified fourteen systematic reviews and meta-analyses and one randomized controlled trial. Six ongoing clinical trials were identified as well as two clinical trials that had been interrupted. In the current state of knowledge, there are no high-level evidence data on the therapeutic contribution of biologic prostheses that allow prioritization of the various biologic prostheses according to their characteristics or their different manufacturing processes.

CONCLUSION

Pending the results of current randomized controlled trials to validate the indications and an eventual specific reimbursement, indications for the use of biologic parietal reinforcement prostheses seems to be limited to rare clinical situations and only after collegial discussion.

Biologic mesh for repair of ventral hernias in contaminated fields: long-term clinical and patient-reported outcomes

BACKGROUND

Guidelines recommend biologic prosthetics for ventral hernia repair (VHR) in contaminated fields, yet long-term and patient-reported data are limited. We aimed to determine the long-term rate of hernia recurrence, and other clinical and patient-reported outcomes following the use of porcine small intestine submucosa (PSIS) for VHR in a contaminated field.

METHODS

Consecutive patients undergoing open VHR with PSIS mesh in a contaminated field from 2004 to 2014 were prospectively evaluated for hernia recurrence and other post-operative complications. Multivariate logistic and Cox regression analyses identified predictors of hernia recurrence and surgical site infection. Patient-reported outcomes were evaluated using SF-36, Hernia-Related Quality-of-Life Survey (HerQLes) and Body Image Questionnaire instruments.

RESULTS

Forty-six hernias were repaired in clean-contaminated [16 (35 %)], contaminated [11 (24 %)] and dirty [19 (41 %)] fields. Median follow-up was 47 months [interquartile range: 31-79] and all patients had greater than 12-month follow-up. Sixteen patients (35 %) were not re-examined. Incidence of surgical site events and surgical site infection were 43 % (n = 20) and 56 % (n = 25), respectively. American Society of Anesthesiologists score 3 or greater was an independent predictor of surgical site infection (odds ratio 5.34 [95 % confidence interval 1.01-41.80], p = 0.04). Hernia recurrence occurred in 61 % (n = 28) with a median time to diagnosis of 16 months [interquartile range 8-26]. After bridged repair, 16 of 18 patients (89 %) recurred, compared to 12 of 28 (43 %) when fascia was approximated (p < 0.01). Bridged repair was an independent predictor of recurrence (odds ratio 10.67 [95 % confidence interval 2.42-76.08], p < 0.01). Patients with recurrences had significantly worse scores on the SF-36 mental health component and self-perceived body image, whereas HerQLes scores were similar.

CONCLUSIONS

Hernia recurrences and wound infections are high with the use of biologic PSIS mesh in contaminated surgical fields. Careful consideration is warranted using this approach.

Bone Marrow-Derived Mesenchymal Stem Cells Enhance Bacterial Clearance and Preserve Bioprosthetic Integrity in a Model of Mesh Infection

Background:

The reported incidence of mesh infection in contaminated operative fields is as high as 30% regardless of the material used. Recently, mesenchymal stem cells (MSCs) have been shown to possess favorable immunomodulatory properties and improve tissue incorporation when seeded onto bioprosthetics. The aim of this study was to evaluate whether seeding noncrosslinked bovine pericardium (Veritas Collagen Matrix) with allogeneic bone marrow–derived MSCs improves infection resistance in vivo after inoculation with Escherichia coli (E. coli).

Methods:

Rat bone marrow–derived MSCs at passage 3 were seeded onto bovine pericardium and cultured for 7 days before implantation. Additional rats (n = 24) were implanted subcutaneously with MSC-seeded or unseeded mesh and inoculated with 7 × 10⁵ colony-forming units of E. coli or saline before wound closure (group 1, unseeded mesh/saline; group 2, unseeded mesh/E. coli; group 3, MSC-seeded mesh/E. coli; 8 rats per group). Meshes were explanted at 4 weeks and underwent microbiologic and histologic analyses.

Results:

MSC-seeded meshes inoculated with E. coli demonstrated superior bacterial clearance and preservation of mesh integrity compared with E. coli–inoculated unseeded meshes (87.5% versus 0% clearance; p = 0.001). Complete mesh degradation concurrent with abscess formation was observed in 100% of rats in the unseeded/E. coli group, which is in contrast to 12.5% of rats in the MSC-seeded/E. coli group. Histologic evaluation determined that remodeling characteristics of E. coli–inoculated MSC-seeded meshes were similar to those of uninfected meshes 4 weeks after implantation.

Conclusions:

Augmenting a bioprosthetic material with stem cells seems to markedly enhance resistance to bacterial infection in vivo and preserve mesh integrity.

Effectiveness and properties of the biological prosthesis Permacol™ in pediatric surgery: A large single center experience

INTRODUCTION

The use of prosthetic patches of non-absorbable materials represents a valid tool in the treatment of abdominal wall and diaphragmatic defects in pediatric age. In recent years research has developed biological dermal scaffolds made from a sheet of acellular matrix that can provide the desired support and reduce the occurrence of complications from non-absorbable implant. We present our experience and a systematic review to evaluate the use of biologic prosthesis for abdominal wall closure in pediatric patients.

METHODS

The study from January 2009 to January 2015 involved 20 patients treated with Permacol™ implant. We observed postoperative complications only in patients treated for abdominal wall closure, which is the major indication for the use of Permacol™. We conducted a systematic review and meta-analysis (according to PRISMA) on PubMed/Medline, Scopus and EMBASE regarding the use of biological prosthesis in pediatric population considering the incidence of complications as the primary outcome.

RESULTS

3/20 patients experienced complications: 2 patients with skin necrosis healed conservatively and 1 of them developed laparocele. Thus only 1 patient with incisional hernia had significant surgery complication. In patients who were permanently implanted with Permacol™ it has not determined adverse reactions with optimal functional outcome.

CONCLUSIONS

In accordance with the few data (case reports and case series) reported in literature about pediatric patients, our experience in different pathologies and applications has shown the effectiveness of Permacol™, in particular for the non-occurrence of infections, that often affect the use of prosthesis.

Surgical mesh for ventral incisional hernia repairs: Understanding mesh design

Surgical mesh has become an indispensable tool in hernia repair to improve outcomes and reduce costs; however, efforts are constantly being undertaken in mesh development to overcome postoperative complications. Common complications include infection, pain, adhesions, mesh extrusion and hernia recurrence. Reducing the complications of mesh implantation is of utmost importance given that hernias occur in hundreds of thousands of patients per year in the United States. In the present review, the authors present the different types of hernia meshes, discuss the key properties of mesh design, and demonstrate how each design element affects performance and complications. The present article will provide a basis for surgeons to understand which mesh to choose for patient care and why, and will explain the important technological aspects that will continue to evolve over the ensuing years.

Surgical mesh for ventral incisional hernia repairs: Understanding mesh design

Surgical mesh has become an indispensable tool in hernia repair to improve outcomes and reduce costs; however, efforts are constantly being undertaken in mesh development to overcome postoperative complications. Common complications include infection, pain, adhesions, mesh extrusion and hernia recurrence. Reducing the complications of mesh implantation is of utmost importance given that hernias occur in hundreds of thousands of patients per year in the United States. In the present review, the authors present the different types of hernia meshes, discuss the key properties of mesh design, and demonstrate how each design element affects performance and complications. The present article will provide a basis for surgeons to understand which mesh to choose for patient care and why, and will explain the important technological aspects that will continue to evolve over the ensuing years.

Retro-rectus repair of complex incisional hernia leads to low recurrence rate

BACKGROUND

To assess the outcome of retro-rectus repair of complex abdominal wall repair (CAWR) in a single institution in relation to the use of biologic and synthetic mesh.

METHOD

A retrospective review was undertaken of complex abdominal wall repairs performed by a single surgical team, assessing the outcome of the retro-rectus repair and factors affecting the outcome.

RESULTS

Between 2007 and 2013, 57 (33 male) patients underwent CAWR retro-rectus repair. The material used was assessed as either synthetic or biologic (cross-linked porcine dermal collagen). The Ventral Hernia Working Group grades were similar between groups of patients having a repair with synthetic and biologic mesh. Median follow-up in the synthetic group was 18 months (1-80.5) and 18.4 months (0.5-70.7) in the biologic group. There was no statistical difference in seroma, wound infection or haematoma rates. No fistulae occurred in either group. Overall recurrence was 3.4% and there was no statistical difference between groups.

CONCLUSION

The retro-rectus repair technique is associated with a low rate of recurrence and is now the technique of choice. The choice of material, biologic or synthetic, in Ventral Hernia Working Group grades 1-3 remains controversial.

Techniques for Abdominal Wall Closure after Damage Control Laparotomy: From Temporary Abdominal Closure to Early/Delayed Fascial Closure-A Review

Open abdomen (OA) has been an effective treatment for abdominal catastrophes in traumatic and general surgery. However, management of patients with OA remains a formidable task for surgeons. The central goal of OA is closure of fascial defect as early as is clinically feasible without precipitating abdominal compartment syndrome. Historically, techniques such as packing, mesh, and vacuum-assisted closure have been developed to assist temporary abdominal closure, and techniques such as components separation, mesh-mediated traction, bridging fascial defect with permanent synthetic mesh, or biologic mesh have also been attempted to achieve early primary fascial closure, either alone or in combined use. The objective of this review is to present the challenges of these techniques for OA with a goal of early primary fascial closure, when the patient's physiological condition allows.

Tissue Expanders in Skin Deficient Ventral Hernias Utilizing Component Separation

Skin deficient complex ventral hernias are complicated surgical cases that have multimodal approaches. There is no current consensus on the management of those patients who also have concomitant stomas or enterocutaneous fistula. We present 2 cases in which the senior authors were able to apply tissue expanders above and between the abdominal wall in patients with an enterocutaneous fistula or stoma. After expansion and final closure, the patients did not experience recurrent hernias.

Living scaffolds: surgical repair using scaffolds seeded with human adipose-derived stem cells

BACKGROUND

Decellularized porcine small intestinal submucosa (SIS) is a biological scaffold used surgically for tissue repair. Here, we demonstrate a model of SIS as a scaffold for human adipose-derived stem cells (ASCs) in vitro and apply it in vivo in a rat ventral hernia repair model.

STUDY DESIGN

ASCs adherence was examined by confocal microscopy and proliferation rate was measured by growth curves. Multipotency of ASCs seeded onto SIS was tested using adipogenic, chondrogenic, and osteogenic induction media. For in vivo testing, midline abdominal musculofascial and peritoneal defects were created in Sprague-Dawley rats. Samples were evaluated for tensile strength, histopathology and immunohistochemistry.

RESULTS

All test groups showed cell adherence and proliferation on SIS. Fibronectin-treated scaffolds retained more cells than those treated with vehicle alone (p < 0.05). Fresh stromal vascular fraction (SVF) pellets containing ASCs were injected onto the SIS scaffold and showed similar results to cultured ASCs. Maintenance of multipotency on SIS was confirmed by lineage-specific markers and dyes. Histopathology revealed neovascularization and cell influx to ASC-seeded SIS samples following animal implantation. ASC-seeded SIS appeared to offer a stronger repair than plain SIS, but these results were not statistically significant. Immunohistochemistry showed continued presence of cells of human origin in ASC-seeded repairs at 1 month postoperation.

CONCLUSION

Pretreatment of the scaffold with fibronectin offers a method to increase cell adhesion and delivery. ASCs maintain their immunophenotype and ability to differentiate while on SIS. Seeding freshly isolated SVF onto the scaffold demonstrated that minimally manipulated cells may be useful for perioperative surgical applications within the OR suite. We have shown that this model for a "living mesh" can be successfully used in abdominal wall reconstruction.

Emerging Trends in Abdominal Wall Reinforcement: Bringing Bio-Functionality to Meshes

Abdominal wall hernia is a recurrent issue world-wide and requires the implantation of over 1 million meshes per year. Because permanent meshes such as polypropylene and polyester are not free of complications after implantation, many mesh modifications and new functionalities have been investigated over the last decade. Indeed, mesh optimization is the focus of intense development and the biomaterials utilized are now envisioned as being bioactive substrates that trigger various physiological processes in order to prevent complications and to promote tissue integration. In this context, it is of paramount interest to review the most relevant bio-functionalities being brought to new meshes and to open new avenues for the innovative development of the next generation of meshes with enhanced properties for functional abdominal wall hernia repair.

Complex ventral hernia repair with a human acellular dermal matrix and component separation: A case series

We present a case series of 19 patients requiring complex abdominal hernia repairs. Patients presented with challenging clinical histories with 95% having multiple significant comorbidities including overweight or obesity (84%), hypertension (53%), diabetes (42%), cancer (26%), and pulmonary disease (16%). The majority of patients (68%) had prior abdominal infections and 53% had at least one failed prior hernia repair. Upon examination, fascial defects averaged 282 cm². Anterior and posterior component separation was performed with placement of a human acellular dermal mesh. Midline abdominal closure under minimal tension was achieved primarily in all cases. Post-operative complications included 2 adverse events (11%) – one pulmonary embolism and one post-operative hemorrhage requiring transfusion; 6 wound-related complications (32%), 1 seroma (5%) and 1 patient with post-operative ileus (5%). Operative intervention was not required in any of the cases and most patients made an uneventful recovery. Increased patient age and longer OR time were independently predictive of early post-operative complications. At a median 2-year follow-up, three patients had a documented hernia recurrence (16%) and one patient was deceased due to unrelated causes.

Conclusion

Patients at high risk for post-operative events due to comorbidities, prior abdominal infection and failed mesh repairs do well following component separation reinforced with a human bioprosthetic mesh. Anticipated post-operative complications were managed conservatively and at a median 2-year follow-up, a low rate of hernia recurrence was observed with this approach.

•

Intraperitoneal placement of acellular dermal matrix using component separation.

•

Acceptable recurrence rates of 16% at 2 years of follow up.

•

Correlation in age and complication chances.

•

Retrorectus technique possibly the best surgical technique for hernia repair.

To band or not to band--early results of banded sleeve gastrectomy

Laparoscopic sleeve gastrectomy (LSG) is the procedure with the fastest growing numbers worldwide. Although excellent weight loss can be achieved, one major obstacle of LSG is weight regain due to sleeve dilatation. Banded sleeve gastrectomy (BLSG) has been described as an option to counteract sleeve dilatation and ameliorate weight loss over time. In a retrospective study, we analysed 25 patients who underwent BLSG using a MiniMizer® ring. Twenty five patients who had previously undergone a conventional LSG were selected for matched-pair analysis. Patient follow-up was 12 months in both groups. Mean preoperative BMI was 56.1 ± 7.2 kg/m(2) for BLSG and 57.0 ± 6.3 kg/m(2) for LSG, P = 0.522. Operative time was significantly shorter for BLSG (53 ± 27 min vs. 68 ± 20 min, P = 0.0025). Excess weight loss (%EWL) was equal in both groups with %EWL at 12 months of 58.0 ± 14.6 % for BSLG patients vs. 58.4 ± 19.2 % for LSG patients. There was no procedure-related mortality in either group. At 12 months postoperative, vomiting was significantly increased in BSLG patients (OR 6.75, P = 0.035). New onset reflux was equal in both groups (OR 0.67, P = 0.469). Ring implantation does not increase the duration of surgery or early surgical complications. Weight loss in the first follow-up year is not influenced, but the incidence of vomiting is raised after 12 months when patients start to increase eating volume.

Mesh herniorrhaphy with simultaneous colorectal surgery: a case-matched study from the American College of Surgeons National Surgical Quality Improvement Program

BACKGROUND

The aim of this study is to evaluate the impact of concurrent mesh herniorrhaphy on short-term outcomes of colorectal surgery by using a large, nationwide database.

METHODS

Patients who underwent simultaneous ventral hernia repair (VHR) and colorectal surgery between 2005 and 2010 were identified from the American College of Surgeons National Surgical Quality Improvement Program. Patients who underwent VHR with mesh repair were case matched with patients who underwent VHR without mesh based on the type of colorectal procedure, diagnosis, and American Society of Anesthesiologists score.

RESULTS

Two hundred sixty-two patients who underwent VHR with mesh were case matched with 524 patients who underwent VHR without mesh. Mean operating time was significantly longer in patients who underwent VHR with mesh (195.8 ± 98.7 vs 164.3 ± 84.4 minutes, P < .001). Postoperative morbidity (P = .58), mortality (P = .27), superficial surgical site infection (SSI) (P = .14), deep SSI (P = .38), organ space SSI (P = .17), wound disruption (P > .99), reoperation (P = .48), and length of hospital stay (P = .71) were comparable between the groups.

CONCLUSION

The American College of Surgeons National Surgical Quality Improvement Program data suggest that VHR with mesh does not increase 30-day mortality, medical or surgical morbidity in colorectal surgery setting.

Safety and durability of one-stage repair of abdominal wall defects with enteric fistulas

OBJECTIVE

To evaluate the safety and long-term durability of 1-stage repair of enteric fistulas in the presence of an abdominal wall defect.

BACKGROUND

Patients with enteric fistulas and an abdominal wall defect present an extreme challenge to surgeons and have been associated with significant morbidity and mortality. Durability of repair is unknown as studies fail to report this or use limited follow-up periods.

METHODS

Chart review was done of consecutive patients who underwent 1-stage repair. Short-term outcomes included morbidity (wound and medical) and mortality. Long-term durability of repair was determined by prospective outpatient follow-up at least 3 years after surgery.

RESULTS

Thirty-nine patients were included with a mean age of 61.2 years, a mean BMI of 24.4 kg/m2, and a mean abdominal wall defect size of 247.9 cm2. Component separation technique was used in 34 (87.2%) and synthetic mesh in 13 (33.3%) patients. There was 1 (2.6%) postoperative death. Twenty-four wound complications developed in 18 (46.2%) patients, including surgical-site infection in 8 (20.5%) patients. Two (5.1%) enteric fistulas recurred and were treated conservatively resulting in closure. Medical complications were seen 36 times in 23 (59%) patients. Twelve of 33 (36.4%) living patients developed a recurrent hernia after a mean follow-up of 62.7 months (range: 36-130).

CONCLUSIONS

One-stage abdominal wall reconstruction with enteric fistula takedown is feasible at the cost of considerable morbidity. Our treatment strategy including component separation technique with synthetic mesh on-demand results in a durable repair in 6 to 7 of 10 patients.

Synthetic Mesh Repair for Incisional Hernia Treatment in High-risk Patients for Surgical Site Occurrences

Patients with incisional hernias (IH) and risk factors for surgical site occurrences (SSOs) such as defined comorbidities and/or potential contaminations are considered to be treated with bioprosthetics. A retrospective analysis of consecutive patients who had undergone elective IH repair with synthetic mesh materials between 2009 and 2013 was conducted. Only patients who were classified into Grades II and III according to the classification of the Ventral Hernia Working Group (VHWG) were considered for the study. Primary outcome parameter was the incidence of SSO. The relationships among demographics, hernia characteristics, surgical technique, and SSOs were also evaluated. Overall, 108 patients were included (Grade II: 68, Grade III: 40). SSO was identified in 14 patients. Having two or more comorbidities ( P = 0.04), an open sublay technique ( P = 0.005), duration of operation ( P = 0.02), larger hernia defects ( P = 0.001), and using larger mesh sizes ( P = 0.01) were associated with significantly higher rates of SSO. Affiliation to VHWG Grading II or III showed no impact on SSO occurrence. Synthetic mesh repair both in an “open sublay” and laparoscopic intraperitoneal technique is safe regarding patients with risk factors for SSO. The recommendations of the VHWG must be declined and a modification of the grading system is warranted overlooking a more liberal use of synthetic meshes.

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

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

Biomechanical evaluation of three fixation modalities for preperitoneal inguinal hernia repair: a 24-hour postoperative study in pigs

PURPOSE

Tacks and sutures ensure a strong fixation of meshes, but they can be associated with pain and discomfort. Less invasive methods are now available. Three fixation modalities were compared: the ProGrip™ laparoscopic self-fixating mesh; the fibrin glue Tisseel™ with Bard™ Soft Mesh; and the SorbaFix™ absorbable fixation system with Bard™ Soft Mesh.

MATERIALS AND METHODS

Meshes (6 cm ×6 cm) were implanted in the preperitoneal space of swine. Samples were explanted 24 hours after surgery. Centered defects were created, and samples (either ten or eleven per fixation type) were loaded in a pressure chamber. For each sample, the pressure, the mesh displacement through the defect, and the measurements of the contact area were recorded.

RESULTS

At all pressures tested, the ProGrip™ laparoscopic self-fixating mesh both exhibited a significantly lower displacement through the defect and retained a significantly higher percentage of its initial contact area than either the Bard™ Soft Mesh with Tisseel™ system or the Bard™ Soft Mesh with SorbaFix™ absorbable fixation system. Dislocations occurred with the Bard™ Soft Mesh with Tisseel™ system and with the Bard™ Soft Mesh with SorbaFix™ absorbable fixation system at physiological pressure (,225 mmHg). No dislocation was recorded for the ProGrip™ laparoscopic self-fixating mesh.

CONCLUSION

At 24 hours after implantation, the mechanical fixation of the ProGrip™ laparoscopic self-fixating mesh was found to be significantly better than the fixation of the Tisseel™ system or the SorbaFix™ absorbable fixation system.

Incisional reinforcement in high-risk patients

Hernia formation after surgical procedures continues to be an important cause of surgical morbidity. Incisional reinforcement at the time of the initial operation has been used in some patient populations to reduce the risk of subsequent hernia formation. In this article, reinforcement techniques in different surgical wounds are examined to identify situations in which hernia formation may be prevented. Mesh use for midline closure, pelvic floor reconstruction, and stoma site reinforcement is discussed. Additionally, the use of retention sutures, closure of the open abdomen, and reinforcement after component separation are examined using current literature. Although existing studies do not support the routine use of mesh reinforcement for all surgical incisions, certain patient populations appear to benefit from reinforcement with lower rates of subsequent hernia formation. The identification and characterization of these groups will guide the future use of mesh reinforcement in surgical incisions.

A review of biocompatibility in hernia repair; considerations in vitro and in vivo for selecting the most appropriate repair material

PURPOSE

Repair of hernia typically makes use of a prosthetic material; synthetic or biologic in nature. Any material which enters the body is subject to interrogation by the inflammation and immune system in addition to numerous other cell families, the outcome of which ultimately determines the success of the repair. In this review, we discuss the fundamental biology which occurs in situ when a biomaterial associates with a tissue, compare and contrast the techniques available to predict this in vitro, and review how features of hernia repair materials specifically may manipulate tissue interrogation and integration. Finally, we conclude our article by examining how biocompatibility impacts surgical practise and how a better understanding of the manner by which materials and tissues interact could benefit hernia repair.

MATERIALS AND METHODS

A review of the literature was conducted using appropriate scientific search engines in addition to inclusion of findings from the groups' primary research.

RESULTS

Using pre-clinical assays to anticipate the biocompatibility of a medical device is critical; however, to maximise the scientific power of in vitro findings, we must carefully consider the in vivo niche of the cells with which we are working. Excessive in vitro culture or contact to non-self materials can add compounding complexity to studies involving leucocytes for instance; therefore, we must ensure careful and stringent assay design when developing techniques for assaying pre-clinical biocompatibility. Furthermore, many of the features associated with hernia repair material design specifically, included to enhance their mechanical or biodegradation characteristics, are inadvertently instructive to cells, and therefore, throughout the prototype stages of a materials development, regular biocompatibility assessment must be performed.

CONCLUSION

The biocompatibility of a material is rate limiting in its ability to function as a medical device. The future of hernia repair materials will rely on close cohesion between the surgical and scientific communities to ensure the most robust biocompatibility assessment techniques, and models are utilised to predict the efficacy of a given material in a particular surgical application.

Porcine acellular dermal matrix for delayed abdominal wall closure after pediatric liver transplantation

Children are one of the groups with the highest mortality rate on the waiting list for LT. Primary closure of the abdominal wall is often impossible in the pediatric population, due to a size mismatch between a large graft and a small recipient. We present a retrospective cohort study of six pediatric patients, who underwent delayed abdominal wall closure with a biological mesh after LT, and in whom early closure was impossible. A non-cross-linked porcine-derived acellular dermal matrix (Strattice(™) Reconstructive Tissue Matrix; LifeCell Corp, Bridgewater, NJ, USA) was used in all of the cases of the series. After a mean follow-up of 26 months (21-32 months), all patients were asymptomatic, with a functional abdominal wall after physical examination. Non-cross-linked porcine-derived acellular dermal matrix (Strattice(™) ) is a good alternative for delayed abdominal wall closure after pediatric LT. Randomized controlled trials are necessary to determine the best moment and the best technique for abdominal wall closure.

Analysis of perioperative factors associated with increased cost following abdominal wall reconstruction (AWR)

BACKGROUND

Ventral hernias are a common, challenging, and expensive problem for both the general and reconstructive surgeons; therefore, the aim of this study is to critically assess perioperative factors related to cost in abdominal wall reconstructions (AWR).

METHODS

A retrospective review of AWR patients from 2007 and 2012 was performed. Analysis of perioperative factors associated with total cost of reconstruction was performed. Linear regression analyses were used to assess independent predictors of total cost.

RESULTS

134 consecutive AWR performed by a single surgeon over a 5-year period at an academic teaching center were included. The average total cost of AWR was $61,251 ± 55,624. Linear regression analysis demonstrated that diabetes (P = 0.026), increased American Society of Anesthesiologists score (P = 0.002), preoperative anemia (P = 0.001), and hernias derived from trauma (P = 0.015) were independently associated with added cost in AWR when controlling for confounding variables. In addition, patients requiring intra-abdominal procedures (P = 0.012) and those receiving an AWR using Acellular Dermal Matrix (P = 0.015) accrued significantly greater cost. Interestingly, preoperative placement of an epidural (P = 0.011) was independently associated with significant cost savings and reduced medical morbidity. Major surgical complications (P < 0.001) and length of stay (P < 0.001) were independently associated with increased cost following AWR.

CONCLUSION

We present a critical assessment of cost in AWR at a major academic teaching hospital and quantify the impact of reconstruction in the setting of medical morbidities and reconstructive complexities. The data from this study can be used to adjust reimbursement schemes and to critically assess the cost-benefit of performing AWR.

Long-term outcome of biologic graft: a case report

INTRODUCTION

Biologic grafts have been shown to support tissue regeneration in various animal models. Very few reports in the literature exist to show tissue remodeling in patients after placement of a biologic graft.

CASE PRESENTATION

We report the case of a 69-year-old Caucasian man with a history of small bowel carcinoid resection and concurrent recurrent ventral hernia repair with component separation and underlay biologic graft placement who underwent re-operation for metastatic carcinoid tumor to his liver. Complete incorporation of the biologic graft was observed. Tissue analysis of the incised midline fascia revealed tissue remodeling at the site of the previous abdominal wall defect.

CONCLUSION

Placement of a biologic graft in ventral hernia repair supports tissue regeneration similar to that previously reported in animal models.

Assessing complications and cost-utilization in ventral hernia repair utilizing biologic mesh in a bridged underlay technique

BACKGROUND

The inability to reapproximate fascia in complex ventral hernia (CVH) repair remains challenging. Single-stage bridging reconstructions have been reported, however, with high rates of recurrence and wound complications. We describe a single-surgeon experience with bridging biologic CVH repair.

METHODS

We reviewed 37 patients undergoing CVH repair with bridging biologic mesh by the senior author from January 1, 2007 to January 1, 2013. Surgical history and operative characteristics were analyzed for predictors of hernia recurrence and wound complications.

RESULTS

Average age was 53 ± 15 years, body mass index was 31.1 ± 8.1 kg/m(2), and history of prior repair in 18 patients. Common indications were trauma, intra-abdominal infection, and prior intra-abdominal surgery. Incidence of wound complications was 51.4%, most commonly wound breakdown and infection. With average follow-up of 13 months, recurrence rate was 18.9% at an average of 8.2 months postoperatively. Analysis demonstrated postoperative wound infection as the only predictor of recurrence (odds ratio = 22.1, P = .017).

CONCLUSIONS

Hernia recurrence rate was 18.9% with bridged biologic CVH repairs, strongly associated with postoperative wound infection. This suggests that patients with postoperative infections may benefit from closer surveillance and more aggressive wound management.

Delayed primary closure of contaminated abdominal wall defects with non-crosslinked porcine acellular dermal matrix compared with conventional staged repair: a retrospective study

INTRODUCTION

Synthetic mesh has been used traditionally to repair abdominal wall defects, but its use is limited in the case of bacterial contamination. New biological materials are now being used successfully for delayed primary closure of contaminated abdominal wall defects. The costs of biological materials may prevent surgeons from using them. We compared the conventional staged repair of contaminated abdominal wall defects with a single-stage procedure using a non-crosslinked porcine acellular dermal matrix.

METHODS

A total of 14 cases with Grade 3 contaminated abdominal wall defects underwent delayed primary closure of the abdomen using a non-crosslinked porcine acellular dermal matrix (Strattice™ Reconstructive Tissue Matrix, LifeCell Corp., Branchburg, NJ, USA). The results were compared with a group of 14 patients who had received conventional treatment for the repair of contaminated abdominal wall defects comprising a staged repair during two separate hospital admissions employing synthetic mesh. Treatment modalities, outcomes, and costs were compared.

RESULTS

In all cases treated with delayed primary closure employing non-crosslinked porcine acellular dermal matrix, there were no complications related to its use. Two patients died due to unrelated events. Although treatment costs were estimated to be similar in the two groups, the patients treated with porcine acellular dermal matrix spent less time as an inpatient than those receiving conventional two-stage repair.

CONCLUSIONS

Delayed primary closure of contaminated abdominal wall defects using a non-crosslinked porcine acellular dermal matrix may be a suitable alternative to conventional staged repair. In our patients, it resulted in early restoration of abdominal wall function and shorter hospitalization. The costs for treating contaminated abdominal wall defects using porcine acellular dermal matrix during a single hospital admission were not higher than costs for conventional two-stage repair. Further randomized studies are needed to expand upon these findings.

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.

Large and complex ventral hernia repair using "components separation technique" without mesh results in a high recurrence rate

BACKGROUND

Recurrence rates after component separation technique (CST) are low in the literature but may be underestimated because of inadequate follow-up methods.

METHODS

Prospective patient follow-up was performed of consecutive patients who underwent repair of large and complex ventral hernias using CST without mesh utilization. Primary outcome was recurrent hernia determined by clinical examination at least 1 year after surgery in all living patients. Current literature underwent meta-analysis regarding outcomes and mode of follow-up.

RESULTS

Seventy-five patients were included with a mean age of 52.2 years and a mean defect size of 214.9 cm(2), respectively. Twenty-nine patients (38.7%) had a recurrent hernia after a mean of 40.9-month follow-up, and this was significantly higher than in the literature (14.0%, P < .01). Sixty-four percent of studies in the literature were unclear about the method of determining recurrent hernia or included telephone follow-up and questionnaires.

CONCLUSIONS

CST coincides with a high recurrence rate when clinical follow-up is longer than a year. Reported recurrence rates are probably underestimated because the method and duration of follow-up are inadequate.

Criteria for definition of a complex abdominal wall hernia

PURPOSE

A clear definition of "complex (abdominal wall) hernia" is missing, though the term is often used. Practically all "complex hernia" literature is retrospective and lacks proper description of the population. There is need for clarification and classification to improve patient care and allow comparison of different surgical approaches. The aim of this study was to reach consensus on criteria used to define a patient with "complex" hernia.

METHODS

Three consensus meetings were convened by surgeons with expertise in complex abdominal wall hernias, aimed at laying down criteria that can be used to define "complex hernia" patients, and to divide patients in severity classes. To aid discussion, literature review was performed to identify hernia classification systems, and to find evidence for patient and hernia variables that influence treatment and/or prognosis.

RESULTS

Consensus was reached on 22 patient and hernia variables for "complex" hernia criteria inclusion which were grouped under four categories: "Size and location", "Contamination/soft tissue condition", "Patient history/risk factors", and "Clinical scenario". These variables were further divided in three patient severity classes ('Minor', 'Moderate', and 'Major') to provide guidance for peri-operative planning and measures, the risk of a complicated post-operative course, and the extent of financial costs associated with treatment of these hernia patients.

CONCLUSION

Common criteria that can be used in defining and describing "complex" (abdominal wall) hernia patients have been identified and divided under four categories and three severity classes. Next step would be to create and validate treatment algorithms to guide the choice of surgical technique including mesh type for the various complex hernias.

Conservative management of mesh-site infection in hernia repair surgery: a case series

PURPOSE

The aim of this study is to assess the outcome of conservative management of infected mesh grafts following abdominal wall hernia repair.

METHODS

This study retrospectively examined the charts of patients who developed mesh-site infection following surgery for abdominal hernia repair to determine how effective conservative management in the form of antibiotics and wound management was on the resolution of infection and wound healing.

RESULTS

Over a period of 30 months, 13 patients developed infected mesh grafts post-hernia repair surgery. Twelve patients were successfully treated conservatively with local wound care and antibiotics if clinically indicated. One patient returned to theatre to have the infected mesh removed. Of the patients that healed eleven were treated with negative pressure wound therapy (VAC(®)).

CONCLUSION

This series of case studies indicate that conservative management of abdominal wall-infected hernia mesh cases is likely to be successful.