Initial evaluation of Permacol bioprosthesis for the repair of complex incisional and parastomal hernias

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.

Prevention of Post-Operative Adhesions: A Comprehensive Review of Present and Emerging Strategies

Post-operative adhesions affect patients undergoing all types of surgeries. They are associated with serious complications, including higher risk of morbidity and mortality. Given increased hospitalization, longer operative times, and longer length of hospital stay, post-surgical adhesions also pose a great financial burden. Although our knowledge of some of the underlying mechanisms driving adhesion formation has significantly improved over the past two decades, literature has yet to fully explain the pathogenesis and etiology of post-surgical adhesions. As a result, finding an ideal preventative strategy and leveraging appropriate tissue engineering strategies has proven to be difficult. Different products have been developed and enjoyed various levels of success along the translational tissue engineering research spectrum, but their clinical translation has been limited. Herein, we comprehensively review the agents and products that have been developed to mitigate post-operative adhesion formation. We also assess emerging strategies that aid in facilitating precision and personalized medicine to improve outcomes for patients and our healthcare system.

The use of Permacol® biological mesh for complex abdominal wall repair

BACKGROUND

Complex abdominal wall repair (CAWR) remains challenging, especially in contaminated fields where the use of a synthetic mesh is associated with prohibitively complication rates. Consequently, biological mesh has been proposed as an alternative. The aim of our study was to evaluate the safety and efficacy of using Permacol® in patients who had CAWR.

METHODS

We retrospectively reviewed the files of patients who had CAWR using the Permacol® mesh. Analysis included patients' preoperative characteristics, procedural parameters, and early and late post-operative complications including mainly recurrence. A multivariate regression model was performed to determine factors that influence 24-months recurrence rate.

RESULTS

Between January 2009 and December 2018, 75 patients. The most common indication was hernia in a contaminated field (48.0%) and abdominal wall defect greater than 10 cm in diameter (36%). Overall, 44% of our patients were Centers for Disease Control (CDC) class II or III and 81.3% fall into category II or III according to the Ventral Hernia Working Group (VHWG) classification. Recurrence rate of our series was 9.3%. Complete fascial closure was achieved in 60 patients (80%). Upon univariate analysis complete fascial closure, posterior component separation, seroma drainage, BMI >30 kg/m2 and age >65 years, VHWD grade >2, DINDO CLAVIEN class > 2 affected the recurrence rate at 2 years follow up. When subcutaneous drains are placed prophylactically, recurrence rates drop from 38.7% (5/14) to 3.3% (2/61 patients) when drains are placed at the time of operation (p=0.02). Only fascial closure affected the 24-months recurrence rate on multivariate analysis (p<0.001).

CONCLUSIONS

Permacol® surgical implant use for CAWR is safe with a relatively low rate of hernia recurrence at 2 years. Prophylactic subcutaneous drain placement may reduce the risk of hernia recurrence. The presence of contaminated fields does not appear to influence hernia recurrence when Permacol® is used, in fact, the only factor that affects recurrence rate at 24-months on multivariate analysis is completeness of the fascial closure.

A retrospective, Italian multicenter study of complex abdominal wall defect repair with a Permacol biological mesh

Complex abdominal wall defects (CAWDs) can be difficult to repair and using a conventional synthetic mesh is often unsuitable. A biological mesh might offer a solution for CAWD repair, but the clinical outcomes are unclear. Here, we evaluated the efficacy of a cross-linked, acellular porcine dermal collagen matrix implant (Permacol) for CAWD repair in a cohort of 60 patients. Here, 58.3% patients presented with a grade 3 hernia (according to the Ventral Hernia Working Group grading system) and a contaminated surgical field. Permacol was implanted as a bridge in 46.7%, as an underlay (intraperitoneal position) in 38.3% and as a sublay (retromuscolar position) in 15% of patients. Fascia closure was achieved in 53.3% of patients. The surgical site occurrence rate was 35% and the defect size significantly influenced the probability of post-operative complications. The long-term (2 year) hernia recurrence rate was 36.2%. This study represents the first large multi-centre Italian case series on Permacol implants in patients with a CAWD. Our data suggest that Permacol is a feasible strategy to repair a CAWD, with acceptable early complications and long-term (2 year) recurrence rates.

Porcine Dermal Collagen Prevents Seroma Formation After Mastectomy and Axillary Dissection in Rats

OBJECTIVE

Seroma occurs as a result of accumulation lymphovascular liquid in the dead space forming after tissue dissection. It is the most common complication after breast surgery. Collagens are the common component of extracellular matrix and have an important role in wound healing. In this study, we aimed to investigate the efficiency of the Porcine Dermal Collagen in preventing Seroma.

MATERIALS AND METHODS

Eighteen young female Wistar rats were used and divided into three groups. Mastectomy and axillary dissection were performed in each group. No other procedures were performed in Group 1 (Control group). Porcine dermal collagen was applied to 50% of the mastectomy field in Group 2 and to 100% of the mastectomy field in Group 3.

RESULTS

Seroma volume was significantly decreased in Group 3 in contrast to Groups 1 and 2 (p<0.001) and in Group 2 in contrast to Group 1 (p<0.001). Vascular proliferation, granulation tissue formation and congestion were significantly increased in Group 3 (p<0.05).

CONCLUSION

We conclude that the use of Porcine Dermal Collagen reduces the formation of seroma in the model of experimental mastectomy and axillary dissection. As the amount of Porcine Dermal Collagen applied increases the formation of seroma reduces.

Use of a porcine dermal collagen implant for contaminated abdominal wall reconstruction in a 105-year-old woman: a case report and review of the literature

INTRODUCTION

Repair of contaminated abdominal wall defect in a geriatric patient is a challenge for the surgeon. We present the case of the oldest patient (105-years old) to successfully undergo a single-stage repair of a contaminated abdominal wall defect with a Permacol™ implant.

CASE PRESENTATION

A 105-year-old Caucasian woman presented to our emergency room with a clinical and radiological diagnosis of small bowel obstruction due to prior operative adhesions. She underwent laparotomy with small bowel resection and primary closure of her abdomen. There was total eventration of her bowel through the suture line 9 days after surgery. She underwent a second laparotomy that revealed no signs of peritonitis or turbid fluid. Her abdomen was closed with a 15 × 10 cm Permacol™ implant sutured sublay with prolene sutures. Her postoperative period was unremarkable. After a follow-up period of 3 years and 2 months, there was no sign of recurrent hernia or wound contamination.

CONCLUSION

We suggest that Permacol™ mesh can be considered an efficient alternative to primary closure or synthetic mesh in geriatric patients with contaminated abdominal wall defects.

Repair of complex parastomal hernias

Development of parastomal hernias (PH) is very common after stoma formation and carries a risk of subsequent bowel incarceration, obstruction and strangulation. The management of PH remains a challenge for the colorectal surgeon, and there are currently no standardized guidelines for the treatment of PH. Even more difficult is the management of complex parastomal hernias (CPH). We conducted a review of the literature to identify recent developments in the treatment of CPH, including analysis of the use of synthetic and biologic mesh prostheses, method of mesh placement and surgical approach.

In vitro comparison of biological and synthetic materials for skeletal chest wall reconstruction

BACKGROUND

Various biological and synthetic materials have been proposed for use in skeletal chest wall reconstruction (SCWR). Because of the lack of studies allowing a direct comparison of SCWR materials, their clinical use often depends on the surgeon's preference and experience. The aim of this study was to analyze 6 synthetic and 3 biological materials frequently used in SCWR with respect to their cytotoxicity, bacterial adhesion, surface characteristics, and mechanical properties to facilitate data-driven decisions.

METHODS

The effect of the SCWR materials and their extracts on the metabolism of human skeletal muscle cells (SkMCs), dermal fibroblasts, adipose cells, and osteoblasts was analyzed in vitro. Bacterial adhesion was quantified by incubating samples in bacterial suspensions (Staphylococcus epidermidis, S aureus, and Escherichia coli), followed by counting colony-forming units and performing scanning electron microscopy. Moreover, the mechanical properties of the materials were analyzed under uniaxial tensile loading to failure.

RESULTS

The metabolism of all cell types seeded on the SCWR materials was reduced compared with untreated cells. With the exception of Vypro (Ethicon, Somerville, NJ), whose extracts significantly reduced fibroblast viability, no cytotoxic leachable substances were detected. Biological materials were less cytotoxic compared with synthetic ones, but they demonstrated increased bacterial adhesion. Synthetic materials demonstrated higher elongation to failure than did biological materials.

CONCLUSIONS

Biological and synthetic SCWR materials showed significant differences in their cytotoxicity, bacterial adhesion, and biomechanical properties, suggesting that they may be used for different indications in SCWR. Further comparable in vivo studies are needed to analyze their performance in different indications of clinical application.

Evaluation of a porcine dermal collagen (permacol) implant for abdominal wall reconstruction in a pediatric multitrauma patient

The presence of a contaminated surgical field in abdominal wall defects caused by trauma presents a challenge for surgeons. Both primary suture and synthetic meshes are strongly discouraged as surgical treatments in such cases. We describe the use of a porcine dermal collagen (Permacol) implant in an eight-year-old patient with multiple injuries. Three months after discharge, the child remains well with good cosmetic results. He is free of pain and has returned to full activity levels with complete wound closure and without any evidence of residual hernia. In conclusion, our experience indicates that the use of Permacol can be considered an efficient technique for reconstructing an infected abdominal wall defect of a pediatric multitrauma patient.

Long-term outcomes (>5-year follow-up) with porcine acellular dermal matrix (Permacol) in incisional hernias at risk for infection

PURPOSE

We reviewed retrospectively all patients undergoing abdominal wall reconstruction using porcine acellular dermal matrix (PADM) from 2004 to 2008 with follow-up assessment in 2012. Technique, short-term (infection, seroma, wound dehiscence), and long-term (mesh infection, recurrence) complications, and hernia recurrences were evaluated by physician examination ≥5 years postoperatively.

RESULTS

56 patients at high risk for infection had elective operation; nine had non-elective operation for complications of prior incisional hernia/hernia repair. Operations were clean, clean-contaminated, contaminated, or grossly infected in 49, 32, 12, and 6%, respectively. Techniques of repair included 10 onlay (six reinforced primary closures, four bridging patches), 47 sublay (20 reinforced primary closures, 27 bridging patches), six inlay, and two sandwich (sublay and onlay). Early complications (≤30 days postoperatively) occurred in 19 of the 65 patients (29%), including two prosthetic dehiscences from fascial attachment, 13 wound infections, and 4 seromas. After a mean follow-up of ≥5 years in 59 of 65 patients, physician-reported incidences of infection requiring removal of mesh or hernia recurrence were 25 and 66%, respectively. Hernia recurrence occurred in 12 of 26 (46%) patients with a reinforced repair and 27 of 33 (82%) with patched repairs. Mesh infection occurred in 7 of 24 patients with sublay patch and in 4 of 19 sublay reinforcement. The greatest recurrence rate was in contaminated (71%) and grossly infected wounds (100%), while recurrence rate was 63% in clean and 63% in clean-contaminated wounds.

CONCLUSIONS

At ≥5 years of follow-up, use of PADM as a bioprosthesis in ventral hernia in high-risk patients is unreliable as a definitive repair in the majority of patients, but may provide satisfactory outcomes in some patients.

Outcome of Abdominal Wall Hernia Repair with Permacol™ Biologic Mesh

The use of biologic mesh in abdominal wall operations has gained popularity despite a paucity of outcome data. We aimed to review the experience of a large healthcare organization with Permacol™. A retrospective study was conducted of patients who underwent abdominal hernia repair with Permacol™ in 14 Southern California hospitals. One hundred ninety-five patients were analyzed over a 4-year period. Operations included ventral/incisional hernia repairs, ostomy closures, parastomal hernia repairs, and inguinal hernia repairs. In 50 per cent of the patients, Permacol™ was used to reinforce a primary fascial repair and in 50 per cent as a fascial bridge. The overall complication rate was 39.5 per cent. The complication rate was higher in patients with infected versus clean wounds, body mass index (BMI) 40 kg/m2 or greater versus BMI less than 40 kg/m2, in patients with prior mesh repair, and when mesh was used as a fascial bridge. With a mean follow-up of 2.1 years, morbid obesity was associated with a higher recurrence. To date this is the largest study on the use of Permacol™ in abdominal wall hernia repair. In our patient population undergoing heterogeneous operations with a majority of wounds as Class II or higher, use of Permacol™ did not eliminate wound morbidity or prevent recurrence, especially in morbidly obese patients.

The persistent challenge of parastomal herniation: a review of the literature and future developments

AIM

The aim of this review article was to outline current evidence relating to the treatment and prevention of parastomal herniation with a view to guide surgeons dealing with patients potentially affected by this complication.

METHOD

Medline and PubMed databases were searched using the keywords 'parastomal hernia/herniation', 'stoma hernia/herniation' and 'stoma complications'. Evidence was obtained from randomized and non-randomized studies. Case reports and articles not written in English were excluded. Qualitative assessment of all included studies was performed using the Oxford Centre for Evidence-Based Medicine 2011 levels of evidence.

RESULTS

The search revealed a total of 228 publications of which 115 fulfilled the selection criteria. Stoma formation through the rectus muscle is complicated by parastomal herniation in up to 50% of cases. There is no conclusive evidence that alternative techniques (e.g. extraperitoneal, lateral rectus abdominis positioned stoma) are superior. Open and laparoscopic parastomal hernia repair have similar recurrence rates up to 50%. The 'Sugarbaker' technique appears to be superior to the 'keyhole' technique when a laparoscopic approach is used. Prophylactic mesh reinforcement of the stoma trephine appears to reduce the herniation rate to approximately 15% and is accompanied by a decrease in symptomatic hernias requiring repair without any difference in stoma-related morbidity.

CONCLUSION

Large prospective controlled trials are required to compare surgical techniques of stoma formation in reducing the incidence of parastomal herniation. Despite limited evidence, routine prophylactic mesh reinforcement of the stoma trephine should be offered to all patients undergoing permanent stoma formation.

Biologic grafts for ventral hernia repair: a systematic review

BACKGROUND

Biologic grafts hold promise of a durable repair for ventral hernias with the potential for fewer complications than synthetic mesh. This systematic review was performed to evaluate the effectiveness and safety of biologic grafts for ventral hernia repair.

METHODS

MEDLINE, Embase, and Cochrane Central Register of Controlled Trials were searched for studies on biologic grafts for the repair of ventral hernias. Outcomes are presented as weighted pooled proportions.

RESULTS

Twenty-five retrospective studies were included. Recurrence depended on wound class, with an overall rate of 13.8% (95% confidence interval [CI], 7.6-21.3). The recurrence rate in contaminated/dirty repairs was 23.1% (95% CI, 11.3-37.6). Abdominal wall laxity occurred in 10.5% (95% CI, 3.7-20.3) of patients. The surgical morbidity rate was 46.3% (95% CI, 33.3-59.6). Infection occurred in 15.9% (95% CI, 9.8-23.2) of patients but only led to graft removal in 4.9% of cases.

CONCLUSIONS

No randomized trials are available to properly evaluate biologic grafts for ventral hernia repair. The current evidence suggests that biologic grafts perform similarly to other surgical options. Biologic grafts are associated with a high salvage rate when faced with infection.

Ventral hernia repair in a potentially septic milieu

Repair of the abdominal wall is the last stage of abdominal surgery; pariet complications, particularly infection, can have serious impact on operative results. While abdominal wound infections are not universally preventable, they are often predictable; the aphorism of Jean Rives (Stoppa, 1999 [1]) summarizes this sequence: "Infection is the mother of postoperative incisional hernia and infection of the incisional hernia repair is the grand-daughter". Repair of the abdominal wall in a potentially septic milieu requires the solution of an equation involving four variables: mechanism of sepsis, its severity, the surgical approach, and choice of prosthetic material. These interdependent variables potentiate each other, requiring adaptations of surgical strategy that cannot be absolutely determined pre-operatively, even with collegial consultation.

A laparoscopic high anterior resection for sigmoid cancer with extraction through incarcerated left inguinal hernia repaired with Permacol mesh

A 65-year-old man presented to the general surgical outpatients with an incarcerated left inguinal hernia. Initial investigations revealed an iron deficiency anaemia that was investigated with a colonoscopy and gastroscopy. This revealed a sigmoid cancer and the staging CT scan confirmed a tumour incarcerated in the sac of the left inguinal hernia. We proceeded with a laparoscopic high anterior resection using the inguinal hernia as the extraction site. The hernia was repaired using Permacol mesh. No postoperative complications occurred.

Giant squamous cell carcinoma as a complication of a chronic enterocutaneous fistula: complex parietal reconstruction

Treatment of an enterocutaneous fistula is complex and may require multidisciplinary management, especially when associated with a neoplastic process. Here, we describe the case of a 59-year-old patient with a squamous cell carcinoma that had invaded the abdominal wall through a chronic enterocutaneous fistula identified 30 years ago. We combined parietectomy with small intestine and colon resection and inguinal lymphadenectomy in order to obtain clear surgical margins. At the same time, plastic surgery involved the implementation of a large bioprosthesis and coverage with a vastus lateralis muscle free flap.

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.

Use of permacol in parietal and general surgery: a bibliographic review

BACKGROUND

The use of synthetic meshes on infected incisional hernias often fails and is therefore contraindicated. Biological meshes offer a novel solution. Among them, Permacol requires a bibliographic analysis of its efficacy and tolerance.

DESIGN

A bibliographic analysis was carried out on the efficacy and tolerance of Permacol in parietal and general surgery.

RESULTS

A total of 22 publications described the use of Permacol in digestive surgery. The advantages of Permacol would be usability in contaminated surgical fields, biocompatibility, no erosion of intestinal wall, and less risk of adhesions. The main drawback of Permacol is its high cost.

CONCLUSION

Even so, Permacol can play an important part in the short-term management of complex or contaminated abdominal wall defects. The lack of long-term studies and the high cost of the implant call for a medical cost-effectiveness assessment to determine the indications for Permacol in parietal and general surgery.

Current strategies and future perspectives for intraperitoneal adhesion prevention

INTRODUCTION

The formation of peritoneal adhesions still is a relevant clinical problem after abdominal surgery. Until today, the most important clinical strategies for adhesion prevention are accurate surgical technique and the physical separation of traumatized serosal areas. Despite a variety of barriers which are available in clinical use, the optimal material has not yet been found.

DISCUSSION

Mesothelial cells play a crucial physiological role in friction less gliding of the serosa and the maintenance of anantiadhesive surface. The formation of postoperative adhesions results from a cascade of events and is regulated by various cellular and humoral factors. Therefore, optimization or functionalization of barrier materials by developments interacting with this cascade on a structural or pharmacological level could give an innovative input for future strategies in peritoneal adhesion prevention. For this purpose, the proper understanding of the formal pathogenesis of adhesion formation is essential. Based on the physiology of the serosa and the pathophysiology of adhesion formation, the available barriers in current clinical practice as well as new innovations are discussed in the present review.

Current practice in abdominoperineal resection: an email survey of the membership of the Association of Coloproctology

INTRODUCTION

This study aimed to gain insight into current preferences for type of surgical approach and patient positioning in abdominoperineal excision of the rectum (APER), to identify whether these factors affect self-reported oncological outcomes and complication rates, and to assess the opinions of members of the Association of Coloproctology of Great Britain and Ireland (ACPGBI) with regards to the benefit of a national training programme for APER surgery.

METHODS

Members of the ACPGBI were surveyed using a questionnaire designed to examine surgeon/departmental demographics, type of APER practised, audit of results and complications, opinions regarding extralevator APER (ELAPER) and opinions regarding the potential benefit of a national training programme.

RESULTS

According to the survey, 62% of surgeons perform perineal dissection in the supine position and 57% perform a standard APER technique. Surgeons who only practise colorectal surgery (p=0.002) and surgeons performing prone dissection (p<0.0001) are more likely to perform ELAPER. Three-quarters (76%) audit their results for perineal wound complication rates. Over 80% audit their oncological outcomes. The vast majority (94.6%) of those who perform ELAPER believe there is a benefit to this method while 59.6% of those who do not perform ELAPER still believe there is a benefit to ELAPER. Only 50% feel that there should be a national training programme.

CONCLUSIONS

There is a distinct discordance with regards to the APER technique. Among UK colorectal surgeons, although a significant proportion favours ELAPER, there remains a larger proportion still performing standard APER techniques.

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.

Dynamic Magnetic Resonance Imaging Demonstrates the Integrity of Perineal Reconstruction following Cylindrical Abdominoperineal Excision with Reconstruction of the Pelvic Floor Using Porcine Collagen

A 72-year-old female presented with a six-month history of increased frequency of defecation, rectal bleeding, and severe rectal pain. Digital rectal examination and endoscopy revealed a low rectal lesion lying anteriorly. This was confirmed histologically as adenocarcinoma. Radiological staging was consistent with a T₃N₂ rectal tumour. Following long-course chemoradiotherapy repeat staging did not identify any metastatic disease. She underwent a laparoscopic cylindrical abdominoperineal excision with en bloc resection of the coccyx and posterior wall of the vagina with a negative circumferential resection margin. The perineal defect was reconstructed with Permacol (biological implant, Covidien) mesh. She had no clinical evidence of a perineal hernia at serial followup. Dynamic MRI images of the pelvic floor obtained during valsalva at 10 months revealed an intact pelvic floor. A control case that had undergone a conventional abdominoperineal excision with primary perineal closure without clinical evidence of herniation was also imaged. This confirmed subclinical perineal herniation with significant downward migration of the bowel and bladder below the pubococcygeal line. We eagerly await further evidence supporting a role for dynamic MR imaging in assessing the integrity of a reconstructed pelvic floor following cylindrical abdominoperineal excision.

Durability of biologic implants for use in hernia repair: a review

In the past 10 years, hernia repair has evolved from primarily using suture closure to using mesh repair. Synthetic mesh implants were the initial gold standard, but the rate of complications such as infection, adhesions, and erosion was higher with synthetics than has been observed with newer biologic implants. As efforts to develop the ideal implant continue, the advantages of biologics for hernia and other soft-tissue repair become increasingly apparent. Animal-sourced biologics have the potential advantage over human dermis of being more amenable to standardization, and porcine dermal collagen architecture closely resembles that of human dermis. Cross-linking the collagen adds strength and durability to the implant that facilitates healing of surgical wounds, just as endogenous collagen, which is cross-linked, has innate durability that enhances natural wound healing. This review defines and assesses durability of the acellular collagen (biologic) implant options available for hernia repair. The factors that affect wound healing-and hernia repair--are summarized. Additionally, the particular features that enhance durability are described, and durability-related clinical outcomes discussed in the literature are cited to aid clinicians in making informed surgical choices.

A transperineal approach to perineal hernia repair using suture anchors and acellular porcine dermal mesh

Perineal hernia following major pelvic surgery is a rare but recognised complication. Various surgical approaches to the repair of a symptomatic perineal hernia have been described. We describe the first reported use of the Mitek suture anchors to secure an acellular porcine dermal graft to the ischia during the transperineal repair of a large perineal hernia.

Intraperitoneal adhesions--an ongoing challenge between biomedical engineering and the life sciences

Peritoneal adhesions remain a relevant clinical problem despite the currently available prophylactic barrier materials. So far, the physical separation of traumatized serosa areas using barriers represents the most important clinical strategy for adhesion prevention. However, the optimal material has not yet been found. Further optimization or pharmacological functionalization of these barriers could give an innovative input for peritoneal adhesion prevention. Therefore, a more complete understanding of pathogenesis is required. On the basis of the pathophysiology of adhesion formation the main barriers currently in clinical practice as well as new innovations are discussed in the present review. Physiologically, mesothelial cells play a decisive role in providing a frictionless gliding surface on the serosa. Adhesion formation results from a cascade of events and is regulated by a variety of cellular and humoral factors. The main clinically applied strategy for adhesion prevention is based on the use of liquid or solid adhesion barriers to separate physically any denuded tissue. Both animal and human trials have not yet been able to identify the optimal barrier to prevent adhesion formation in a sustainable way. Therefore, further developments are required for effective prevention of postoperative adhesion formation. To reach this goal the combination of structural modification and pharmacological functionalization of barrier materials should be addressed. Achieving this aim requires the interaction between basic research, materials science and clinical expertise.

Parastomal hernia repair outcomes in relation to stoma site with diisocyanate cross-linked acellular porcine dermal collagen mesh

PURPOSE

Biologic meshes are increasingly used in parastomal hernia repair. This study evaluates the efficacy and safety of diisocyanate cross-linked acellular porcine dermal collagen mesh for parastomal hernia repair, with particular reference to the relationship of the stoma site to the rectus sheath.

METHODS

Hernias were repaired via a lateral approach, with onlay placement of the biologic mesh. A retrospective case note review and analysis of clinical outcomes was performed. The relationship of the stoma to the rectus sheath was determined by abdominal computed tomography (CT) and intraoperative findings.

RESULTS

Over a 16-month period, 27 consecutive patients, median age 72 years, underwent parastomal hernia repair utilising onlay biologic mesh to reinforce the external oblique aponeurosis. There were 20 paracolostomy and seven paraileostomy hernias. Eleven stomas passed through the rectus sheath and 16 were lateral to it. Recurrences occurred in 3 of 11 stomas within and 12 of 16 stomas lateral to the rectus sheath (P = 0.022). The median time to recurrence was 10.1 months. The median follow up of patients without recurrence was 16.6 months (range 0.2-39.3). There was one perioperative death. One patient developed a superficial post-operative abscess that was managed conservatively, but there were no complications related to the biologic mesh and no mesh required removal.

CONCLUSIONS

For parastomal hernias within the rectus sheath, diisocyanate cross-linked porcine dermal collagen mesh onlay repair gives good results and is safe to use. Repair of a parastomal hernia where the stoma is lateral to the rectus sheath has a significantly higher risk of recurrence and is not recommended.

Repair of parastomal hernias with biologic grafts: a systematic review

BACKGROUND

Biologic grafts are increasingly used instead of synthetic mesh for parastomal hernia repair due to concerns of synthetic mesh-related complications. This systematic review was designed to evaluate the use of these collagen-based scaffolds for the repair of parastomal hernias.

METHODS

Studies were retrieved after searching the electronic databases MEDLINE, EMBASE and Cochrane CENTRAL. The search terms 'paracolostomy', 'paraileostomy', 'parastomal', 'colostomy', 'ileostomy', 'hernia', 'defect', 'closure', 'repair' and 'reconstruction' were used. Selection of studies and assessment of methodological quality were performed with a modified MINORS index. All reports on repair of parastomal hernias using a collagen-based biologic scaffold to reinforce or bridge the defect were included. Outcomes were recurrence rate, mortality and morbidity.

RESULTS

Four retrospective studies with a combined enrolment of 57 patients were included. Recurrence occurred in 15.7% (95% confidence interval [CI] 7.8-25.9) of patients and wound-related complications in 26.2% (95% CI 14.7-39.5). No mortality or graft infections were reported.

CONCLUSIONS

The use of reinforcing or bridging biologic grafts during parastomal hernia repair results in acceptable rates of recurrence and complications. However, given the similar rates of recurrence and complications achieved using synthetic mesh in this scenario, the evidence does not support use of biologic grafts.

[Conventional reparation of parastomal hernia]

The reparation of parastomal hernias and their recurrence remain problematic although the implementation of mesh techniques has lowered recurrences rates. Conventional surgical techniques include suture repair, relocation of the stoma as well as diverse hernia repair procedures with mesh implantation. Suture repair has been abandoned due to its high recurrence rate. Simple relocation is not recommended because of high rates of recurrent parastomal hernias. Conventional hernia repair using mesh implants is classified according to the mesh position into epifascial (onlay), retromuscular (sublay) and intraperitoneal (IPOM) techniques. Furthermore, a combination of relocation with additional mesh enforcement is also possible. The value of the different mesh techniques and of new biological mesh prostheses must be evaluated in randomized controlled studies.