Closure of Abdominal Wall Defects Using Acellular Dermal Matrix

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

In Situ Cross-Linked Collagen-Based Biological Patch Integrating Anti-Infection and Anti-Calcification Properties

Acellular dermal matrix (ADM) can be used as collagen-based biological patches for regeneration and repair of soft tissues in vivo. However, the problems of calcification and infection during treatment with patches can lead to premature patch failure and even to a severely increased risk of recurrence. In this study, first, porcine ADM (pADM) grafted with vinyl underwent an in situ cross-linking reaction in the presence of an initiator, while quaternary ammonium groups were introduced into the pADM during the cross-linking process to obtain MA-DMC-pADM, which is a biological patch with anti-infection and anti-calcification properties. The results of physicochemical property tests of the material showed that the pADM after cross-linking had better physical and mechanical properties. Importantly, antibacterial and anti-calcification experiments showed that MA-DMC-pADM had a good antibacterial and anti-calcification effect. Therefore, the MA-DMC-pADM biological patch facilitates their longer-lasting effectiveness, allowing pADM to be used in a wider range of applications.

In Vivo Comparison of Three Human Acellular Dermal Matrices for Breast Reconstruction

BACKGROUND/AIM

Acellular dermal matrices (ADMs) have become popular in implant-based breast reconstruction. The aim of this study was to compare three commonly used ADM products in vivo in an animal model.

MATERIALS AND METHODS

The nucleic acid content (residual double-stranded DNA) and the levels of the remaining growth factors after decellularization were measured for each ADM. Cytocompatibility with ADMs was documented using NIH 3T3 mouse fibroblast cells. In vivo, the implanted ADMs were histologically evaluated at 1, 2, 3, and 6 months (n=5) using male 8-week-old Sprague-Dawley rats.

RESULTS

Fibroblasts grew in the SureDerm HD and DermACELL with no cytotoxicity. In a rat model, SureDerm HD and DermACELL incorporated more readily into the surrounding host tissue, as measured by rapid cell influx and collagen deposition, and showed more delayed tissue remodeling with decreased matrix metalloproteinases levels compared to AlloDerm.

CONCLUSION

SureDerm HD and DermACELL can be used as biological materials for breast reconstruction.

Development of an evidence-based approach to the use of acellular dermal matrix in immediate expander-implant-based breast reconstruction

BACKGROUND

Although acellular dermal matrix (ADM) is widely used in expander-implant-based breast reconstructions, previous analyses have been unable to demonstrate improvements in patient-reported outcomes (PROs) with this approach over non-ADM procedures. This study aims to develop a more selective, evidence-based approach to the use of ADM in expander-implant-based breast reconstruction by identifying patient subgroups in which ADM improved clinical outcomes and PROs.

STUDY DESIGN

The Mastectomy Reconstruction Outcomes Consortium Study prospectively evaluated immediate expander-implant reconstructions at 11 centers from 2012 to 2015. Complications (any/overall and major), and PROs (satisfaction, physical, psychosocial, and sexual well-being) were assessed two years postoperatively using medical records and the BREAST-Q, respectively. Using mixed-models accounting for centers and with interaction terms, we analyzed for differential ADM effects across various clinical subgroups, including age, body mass index, radiation timing, and chemotherapy.

RESULTS

Expander-implant-based breast reconstruction was performed in 1451 patients, 738 with and 713 without ADM. Major complication risk was higher in ADM users vs. nonusers (22.9% vs. 16.4% and p = 0.04). Major complication risk with ADM increased with higher BMI (BMI=30, OR=1.70; BMI=35, OR=2.29, interaction p = 0.02). No significant ADM effects were observed for breast satisfaction, psychosocial, sexual, and physical well-being within any subgroups.

CONCLUSION

In immediate expander-implant-based breast reconstruction, ADM was associated with a greater risk of major complications, particularly in high-BMI patients. We were unable to identify patient subgroups where ADM was associated with significant improvements in PROs. Given these findings and the financial costs of ADM, a more critical approach to the use of ADM in expander-implant reconstruction may be warranted.

Pericardial flap to repair a pulmonary laceration in a cat with pyothorax

Case summary

A 2-year-old female neutered domestic shorthair cat was presented for investigation of acute onset tachypnoea and dyspnoea. Pyothorax was diagnosed based on thoracic radiographs and fluid analysis. Medical treatment consisted of bilateral thoracostomy tube placement, antibiotic therapy and thoracic lavage. After 12 days of medical management infection was still present, warranting exploratory thoracotomy. At surgery, encapsulated abscesses were found in the left lung, right cranial and right middle lobes. The right caudal lobe was the only macroscopically non-abscessated lobe, and appeared to have a parenchymal laceration 8 mm long over the dorsolateral surface. Following partial pericardiectomy, mediastinectomy and debridement of abscesses, a pericardial flap was reflected caudolaterally and apposed over the laceration to seal the affected lung lobe. This flap was sutured to a rim of fibrinous adhesion that was partially covering this lobe. After 8 days the cat was discharged with antibiotic therapy for 3 more weeks. Follow-up assessment at 19 and 38 weeks postoperatively confirmed the cat to have good exercise tolerance. Thoracic radiographs at 19 weeks revealed good bilateral aeration of the pulmonary parenchyma without pleural effusion.

Relevance and novel information

Lung lobe laceration can be treated by lung lobectomy or direct suturing of the lung parenchyma. This is the first report using a pericardial flap to repair a lung laceration. Pericardial flap was successfully used to treat this lung laceration where lobectomy was contraindicated. Encouraging results were present at 8 months postoperatively.

Clinical, histological, and ultrasound follow-up of breast reconstruction with one-stage muscle-sparing "wrap" technique: A single-center experience

BACKGROUND

Prepectoral implant placement and complete coverage with porcine acellular matrix after mastectomy is a new concept in breast surgery presented in few cases in the literature. This paper aimed to present our single-center experience in one-stage breast reconstruction muscle-sparing "wrap" technique by evaluating clinical and aesthetic outcomes, ultrasound and histological examination, and patient quality of life.

METHODS

From January 2014 to January 2017, 52 patients (40 unilateral, 12 bilateral) underwent one-stage muscle-sparing breast reconstructions with Braxon^® acellular dermal matrix and implant. In 3 patients, a surgical biopsy and histological examination with immunohistochemical analysis of the periprosthetic tissue were performed. All patients underwent breast ultrasound examination, and the occurrence of capsular contracture was assessed through the Baker classification and by measuring the mammary compliance scores with the Antoon Paar Mammary compliance system. Breast appearance was evaluated using a visual analogue scale (VAS) and in terms of quality of life using the EOCRT QLQ C-30 and QLQ BR-23 questionnaires.

RESULTS

Early and late postoperative complications are reported. Histological and ultrasound evaluation showed a complete integration of the matrix. According to the VAS scale, the EOCRT QLQ C-30, and QLQ BR-23, patients' satisfaction resulted in a high score in terms of quality of life and aesthetic outcomes.

CONCLUSION

The results of this new surgical technique in selected cases are promising in terms of effectiveness and low rate of postoperative complications, but further long-terms evaluations are required.

Small Bowel Fistulas and the Open Abdomen

Over the last 15 years, the contemporary strategies to treat the open abdomen have reduced the lethal complications. Systematic intensive care and modern wound management in conjunction with a plastic barrier to protect the viscera and topical negative pressure on the soft tissues have reduced the development of small bowel fistulas. The literature selected for this review shows that the surgical handling of the exposed bowel, the choice of the material for temporary coverage and early progressive closure of the defect are crucial for the prevention of fistulas. At present, surgeons worldwide have adopted these principles leading to an increase of primary or delayed closure rates. When a small fistula occurs, biological dressings like human acellular dermal matrix and fibrin glue may help to seal the orifice and to treat the patient conservatively. In case of a large fistula, vacuum-assisted wound management is recommended as well. Through a separate hole in the vacuum sponge matching to the fistula, the enteric contents are sucked off while the wound bed heals and is prepared for split thickness skin graft. Surgical resection of established fistula unresponsive to conservative measures should only be performed on patients well-nourished and free of infection with a delay of at least six months. for patients with an open abdomen, surgical expertise and a well-structured management plan offer the best chances to overcome this potentially devastating condition — with or without fistula.

Early Definitive Closure of the Open Abdomen: A Quiet Revolution

Contrary to the management strategy recommended only 2-3 years ago, temporarily covering the open abdomen with an absorbable mesh or a plastic sheath without preserving the peritoneal space is no longer considered in the patient's best interest. The use of the vacuum pack, in conjunction with vacuum-assisted wound management and new biological prostheses now offer patients with an open abdomen a better and simpler alternative to the giant "planned ventral hernia". With very few exceptions in the most critically ill patients, the survivors of damage control surgery or infected pancreatic necrosis should not be sent home with a huge defect only to undergo a complex reconstruction a year later. Simpler and better alternatives exist. The new concepts and technologies presented in this review, when widely adopted, will rapidly translate into safer and better management of the patient with an open abdomen.

In vitro pressure manifolding distribution evaluation of ABThera(™) Active Abdominal Therapy System, V.A.C.(®) Abdominal Dressing System, and Barker's vacuum packing technique conducted under dynamic conditions

OBJECTIVES

Temporary abdominal closure methods allow for management of open abdomens where immediate primary closure is not possible and/or where repeat abdominal entries are necessary. We assessed pressure mapping and fluid extraction efficiency of three open abdomen dressing systems: ABThera(™) Active Abdominal Therapy System, V.A.C.(®) Abdominal Dressing System, and Barker's vacuum packing technique.

METHODS

An in vitro test model was designed to simulate physical conditions present in an open abdomen. The model consisted of a rigid rest platform with elevated central region and a flexible outer layer with centrally located incision. Constant -125 mmHg negative pressure was applied according to the type of system, under simulated dynamic conditions, using albumin-based solution with a viscosity of 14 cP. Data were collected by pressure sensors located circumferentially into three concentric zones: Zone 1 (closest to negative pressure source), Zone 2 (immediately outside of manifolding material edge), and Zone 3 (area most distal from negative pressure source). Each value was the result of approximately 100 pressure readings/zone/experiment with a total of three experiments for each system.

RESULTS

Pressure distribution of ABThera Therapy was significantly (p < 0.05) superior to Barker's vacuum packing technique in all three evaluated zones. Similarly, V.A.C. Abdominal Dressing System pressure distribution was significantly (p < 0.05) improved compared to Barker's vacuum packing technique in all zones. There were no pressure distribution differences in Zone 1 between ABThera Therapy and V.A.C. Abdominal Dressing System; however, in Zones 2 and 3, ABThera Therapy was significantly (p < 0.05) superior to V.A.C. Abdominal Dressing System.

CONCLUSIONS

These data suggest that all approaches to negative pressure therapy for open abdomen treatment are not equal. Additional research should be conducted to elucidate clinical implications of data demonstrated here.

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.

Use of vascularized posterior rectus sheath allograft in pediatric multivisceral transplantation--report of two cases

Restoring abdominal wall cover and contour in children undergoing bowel and multivisceral transplantation is often challenging due to discrepancy in size between donor and recipient, poor musculature related to birth defects and loss of abdominal wall integrity from multiple surgeries. A recent innovation is the use of vascularized posterior rectus sheath to enable closure of abdomen. We describe the application of this technique in two pediatric multivisceral transplant recipients--one to buttress a lax abdominal wall in a 22-month-old child with megacystis microcolon intestinal hypoperistalsis syndrome and another to accommodate transplanted viscera in a 10-month child with short bowel secondary to gastoschisis and loss of domain. This is the first successful report of this procedure with long-term survival. The procedure has potential application to facilitate difficult abdominal closure in both adults and pediatric liver and multivisceral transplantation.

Acellular dermal matrices: Use in reconstructive and aesthetic breast surgery

Acellular dermal matrices (ADMs) were first described for use in breast surgery in 2001. Since this initial report, ADMs have become an increasingly common component of implant-based breast procedures. ADMs have shown promise for use in both aesthetic and reconstructive breast surgery; however, concerns about their use remain because of the significant costs associated with these products. The present article reviews the history of ADM use in breast surgery and the outcomes reported to date. Common techniques for placement of ADMs in aesthetic revisionary and breast reconstruction surgery are provided, and use in the setting of chest wall irradiation and capsular contracture is discussed. Finally, the authors comment on the cost implications of these products in the Canadian and American health care systems.

Abdominal wall repair using human acellular dermal matrix: a follow-up study

BACKGROUND

The role of acellular dermal matrix (ADM) in abdominal wall reconstruction (AWR) is unclear. The aim of this study was to review the management, complications, and long-term outcomes of AWR using ADM in a large surgical cohort.

METHODS

Retrospective chart review of patients undergoing AWR using ADM from 2004 to 2007 was performed. Demographic data, comorbidities, complications, and long-term outcomes were collected.

RESULTS

There were 77 cases in 68 patients with mean age of 61.1 +/- 1.4 years. The most common indication was infected fascia (n = 19 [25%]). Wound closure was achieved in 75% of the cases via primary (n = 26 [45%]), secondary intention (n = 17 [29%]), or skin graft (n = 15 [26%]). Nonprimary closure was achieved in 5.7 +/- .7 months. There were 32 perioperative (39%) and 33 long-term (43%) complications. Over a mean follow-up period of 13.2 +/- 1.5 months, the hernia recurrence rate was 27% (n = 21).

CONCLUSION

Although ADM is a viable option in AWR, the high hernia recurrence rate warrants a continued search for alternative biologic materials to improve outcomes.

Immediate repair of major abdominal wall defect after extensive tumor excision in patients with abdominal wall neoplasm: a retrospective review of 27 cases [corrected]

BACKGROUND

The treatment of abdominal wall neoplasm continues to present a challenging problem because it is not easy to repair the giant defect which is resulted from extensive tumor excision. Some techniques and materials have been reported, but most report a certain technique or material for abdominal wall reconstruction. Therefore, we retrospectively reviewed the treatment of such patients in our department and assessed the reconstruction algorithm in such a situation.

METHODS

We studied 27 patients undergoing immediate abdominal wall reconstruction between 1999 and 2008 who sought care for major defects after extensive tumor excision of malignancy. We categorized the defects into three types: type I, defects involving only the loss of skin (15 cases); type II, myofascial defects with intact skin coverage (6 cases); and type III, myofascial defects without skin coverage (6 cases). Different techniques and materials were used. Postoperative morbidities, sign of herniation, and other follow-up data were recorded.

RESULTS

The immediate abdominal wall reconstruction was successful in all patients. There was no severe morbidity after the operation. Only one patient developed hernia.

CONCLUSIONS

Most type I defects can be corrected with primary suture. For type II defects, a prosthetic or biological mesh, or alternatively an autologous fascial substitute, may be used. For type III defects, the resulting full-thickness defect will require a myocutaneous flap, such as the tensor fascia lata flap, with or without a mesh for abdominal wall reconstruction. Human acellular dermal matrix, a biological mesh, is an ideal alternative for synthetic mesh, especially in situations of infection or contamination.

Long-term outcome of acellular dermal matrix when used for large traumatic open abdomen

BACKGROUND

The purpose of this study is to prospectively examine the use of Human Acellular Dermal Matrix (HADM) in trauma patients with large open abdominal wounds and assess the long-term outcome. Previous studies have not examined the long-term outcomes in trauma patients with abdominal wall reconstructions.

METHODS

An institutional review board approved prospective case series of consecutive patients admitted to a level I university trauma center, who were unable to have their abdomen closed primarily after trauma laparotomy. These patients had HADM placed to attain closure of the abdomen with skin advancement flaps to cover the HADM when possible. Our primary outcome measure was hernia formation and our secondary outcomes were laxity, fistulae, and infections associated with HADM.

RESULTS

Ten patients were enrolled during a 1-year period. Mean time to HADM placement was 17.2 days +/- 3.6 days. Mean initial defect size was 425.1 cm2 +/- 75.9 cm2 with the largest 770 cm2. Thirty day follow-up showed no recurrence in 100% patients. Six patients remained for long-term follow-up. Follow-up at 60 days demonstrated significant laxity or recurrent hernia or both in 67% of patients, and this increased to 100% by the end of 1 year follow-up. There were no bowel fistulae in these patients closed with HADM but 20% with infection.

CONCLUSIONS

HADM is an alternative available to reconstruct the unclosable open abdomen with no fistulae formation, however, it is associated with a high rate of laxity in large abdominal wounds.

Cryopreserved human amniotic membrane for soft tissue repair in rats

Fresh amniotic membrane has been used in medicine since 1910. The reconstruction of immunologic privileged ocular surfaces with cryopreserved amniotic membrane was introduced in the 1990s. The aim of this study was to analyze the use of cryopreserved human amniotic membrane (HAM) as a surgical patch in immunologic unprivileged anatomic sites. In part I of the investigation, the abdominal wall muscle of 36 rats was covered with mono- and multilayered HAM. After 3, 14, and 28 days, respectively, these grafts were evaluated macro- and microscopically. Multilayer samples displayed slower degradation and less inflammation compared with monolayer coverage. In part II of the study, abdominal wall closure with multilayer HAM and with polypropylene mesh was conducted in 20 rats. All rats showed sufficient closure after 21 days, but significantly lower intraabdominal adhesion formation was observed in the HAM rats. The results of this study might pave the way for the use of cryopreserved HAM as graft material in reconstructive surgery.

Use of human acellular dermal matrix for abdominal wall reconstructions

BACKGROUND

Acellular dermal matrix (ADM) represents a promising new fascial substitute for repairing abdominal wall defects.

METHODS

We retrospectively studied 63 patients who underwent fascial reconstruction with ADM and analyzed risk factors for recurrence and infectious wound complications.

RESULTS

Postoperative wound infections, noninfectious wound complications, and recurrences developed in 35%, 44%, and 41% of patients, respectively. No patients required ADM removal. Long surgical times (> or =300 min), implants of 100 cm(2) or greater, and repairs using 3 or more ADM sheets were associated significantly with the development of a postoperative wound infection. The approximation of ADM directly to the fascial edge (P = .02), long surgical time (P < .01), implant size of 100 cm(2) or greater (P = .01), and the presence of a postoperative wound infection (P = .02) were associated significantly with recurrence.

CONCLUSIONS

Recurrences and complications after ADM fascial repairs may be higher than previously reported and associated with implant size and method of implantation. Postoperative infection, although not necessitating implant removal, is associated with more recurrences.

Generating elastic, biodegradable polyurethane/poly(lactide-co-glycolide) fibrous sheets with controlled antibiotic release via two-stream electrospinning

Damage control laparotomy is commonly applied to prevent compartment syndrome following trauma but is associated with new risks to the tissue, including infection. To address the need for biomaterials to improve abdominal laparotomy management, we fabricated an elastic, fibrous composite sheet with two distinct submicrometer fiber populations: biodegradable poly(ester urethane) urea (PEUU) and poly(lactide-co-glycolide) (PLGA), where the PLGA was loaded with the antibiotic tetracycline hydrochloride (PLGA-tet). A two-stream electrospinning setup was developed to create a uniform blend of PEUU and PLGA-tet fibers. Composite sheets were flexible with breaking strains exceeding 200%, tensile strengths of 5-7 MPa, and high suture retention capacity. The blending of PEUU fibers markedly reduced the shrinkage ratio observed for PLGA-tet sheets in buffer from 50% to 15%, while imparting elastomeric properties to the composites. Antibacterial activity was maintained for composite sheets following incubation in buffer for 7 days at 37 degrees C. In vivo studies demonstrated prevention of abscess formation in a contaminated rat abdominal wall model with the implanted material. These results demonstrate the benefits derivable from a two-stream electrospinning approach wherein mechanical and controlled-release properties are contributed by independent fiber populations and the applicability of this composite material to abdominal wall closure.

Reconstruction of the abdominal wall by using a combination of the human acellular dermal matrix implant and an interpositional omentum flap after extensive tumor resection in patients with abdominal wall neoplasm: A preliminary result

AIM: To present our trial using a combination of the human acellular dermal matrix (HADM) implant and an interpositional omentum flap to repair giant abdominal wall defects after extensive tumor resection.

METHODS: Between February and October of 2007, three patients with giant defects of the abdominal wall after extensive tumor resection underwent reconstruction with a combination of HADM and omentum flap. Postoperative morbidities and signs of herniation were monitored.

RESULTS: The abdominal wall reconstruction was successful in these three patients, there was no severe morbidity and no signs of herniation in the follow-up period.

CONCLUSION: The combination of HADM and omentum flap offers a new, safe and effective alternative to traditional forms in the repair of giant abdominal wall defects. Further analysis of the long-term outcome and more cases are needed to assess the reliability of this technique.

Mechanical Abrasion Improves Early Incorporation of Small Intestinal Submucosa

It has been shown that gross incorporation of porcine-derived small intestinal submucosa (SiS) is limited at 2 weeks. This study evaluates a technique for improving the early incorporation of implanted eight-ply SiS. Six pigs underwent implantation of SiS on the peritoneal surface using three techniques: suture fixation of stock-perforated SiS, suture fixation of manually perforated SiS, and suture fixation of stock-perforated SiS to mechanically abraded peritoneum. Gross incorporation was evaluated and random samples harvested for tensiometric analysis 2 weeks after implantation. SiS placed onto mechanically abraded peritoneum demonstrated significantly greater gross incorporation than both stock-perforated SiS (100% versus 42%, P = 0.015) and manually perforated SiS (100% versus 50%, P = 0.042). There was no difference in gross incorporation between stock and manually perforated SiS. Using tensiometric analysis, the force required to separate the peritoneum from the SiS implant was significantly greater for the SiS placed onto mechanically abraded peritoneum (4.4 ± 1.7 kg · f/cm2) than for both the stock-perforated SiS samples (1.0 ± 0.5 kg · f/cm2) and the needle-perforated SiS samples (1.4 ± 0.9 kg · f/cm2; P < 0.001). There was no difference between stock and manually perforated SiS at 2 weeks. Mechanical abrasion of the peritoneum before SiS onlay leads to improved gross incorporation 2 weeks after implantation in a porcine model of herniorrhaphy. Long-term studies and histologic analysis are needed to validate this method as a means for improving early incorporation of SiS.

Evaluation of DBM/AM composite as a graft substitute for posterolateral lumbar fusion

Demineralized bone matrix (DBM) has been investigated as a bone graft substitute for spinal fusion with less morbidity. Various carriers have been added to DBM to enhance its handling characteristics. This study investigates the spinal fusion induced by a composite of DBM and acellular dermal matrix (AM) in comparison with autologous bone in an athymic rat spinal fusion model. Single-level intertransverse process fusions were performed in 60 athymic nude rats grafted with 2 mL/kg of DBM/AM composite, AM alone, or autologous bone. Fusion was assessed at 6 weeks by radiography, manual palpation, and histology. At 6 weeks, 70% of the animals from the DBM/AM composite group exhibited complete spine fusion, whereas 35% from the autologous bone group and 20% from AM group showed bridging with some gaps. The DBM/AM composite induced a significantly higher fusion rate than both the autologous bone and AM groups (p < 0.001) in all measured parameters. The current study demonstrated that using DBM/AM composite can have more robust fusion than autologous bone at 6 weeks in an athymic rat spinal fusion model.

Use of porcine dermal collagen graft and topical negative pressure on infected open abdominal wounds

This article reports on two cases in which porcine dermal collagen grafts were used successfully alongside topical negative pressure therapy in order to close open abdominal wounds in which severe infection was present.

Use of human acellular dermal matrix in complex and contaminated abdominal wall reconstructions

BACKGROUND

Few good surgical options exist for the repair of complex anterior abdominal wall defects, particularly those in which bacterial contamination is present. The use of prosthetic mesh increases complication rates when the mesh is placed directly over viscera or when the surgical site is contaminated from a pre-existing infection or enteric spillage. The use of an acellular dermal matrix (ADM), which becomes vascularized and remodeled into autologous tissue after implantation, may represent a low-morbidity alternative to prosthetic mesh products in these complex settings. This study examined our experience with ADM in the reconstruction of contaminated abdominal wall defects.

METHODS

Patients undergoing abdominal wall reconstructions in the face of contamination with ADM between May 2002 and December 2005 underwent retrospective chart review. Demographics, indications for ADM placement, plane of implantation, complications, and follow-up data were evaluated.

RESULTS

Sixty-seven patients were identified. The indications for ADM placement included incarcerated hernias, infected mesh, fistulae, early/delayed abdominal wall reconstruction after intra-abdominal catastrophe or trauma, dehiscence/evisceration, and spillage of enteric contents. The ADM was positioned either above the fascia or beneath the fascia or was sutured directly to the fascial edges. Sixteen patients developed a wound infection; the majority of these were superficial and required only local wound care, 5 required some further surgical intervention, and 2 required removal of the ADM. Twelve patients developed recurrent hernias. The mean follow-up time for the study population was 10.6 months.

CONCLUSIONS

ADM can be used safely and effectively as an alternative to traditional mesh products for abdominal wall reconstructions, even in the setting of contaminated fields.

Abdominal Wall Reconstruction in a Trauma Setting

According to the World Health Organization "Global burden of disease study", future demographics of trauma are expected to show an increase in morbidity and mortality. In the past few decades, the field of trauma surgery has evolved to provide global and comprehensive care of the injured. While the modern day trauma surgeon is well trained to deal with multitrauma patients with injuries involving several systems, the ever-increasing nature and variety of multitrauma has left lacuna in certain areas. One such area is the management of abdominal wall injuries, which has been the domain of both plastic and reconstructive and general surgeons. The trauma surgeon is adept at treating the contents of the abdomen but not always the container. If not managed properly complications associated with abdominal wall injuries can lead to increased morbidity and mortality. In considering reconstruction of the abdominal wall in multitrauma patients proper evaluation, scrupulous planning, appropriate, and meticulous technique improve the chances for success with minimal complications. In the present article, we provide a brief description of the most commonly used procedures, and more importantly we outline the principles and guidelines applied to abdominal wall reconstruction in order to inform the trauma surgeon of different available treatment options. In doing so, we hope that this review will assist trauma surgeons in their overall care of patients that present with abdominal injuries.

Acellular dermal matrix in the management of high-risk abdominal wall defects

BACKGROUND

Ventral hernia repair in the face of a contaminated field or with questionable skin coverage requires either complex abdominal wall flaps or a staged repair. The development of biologic prostheses has altered the approach to these difficult clinical problems.

METHODS

The study population consisted of human acellular dermal matrix (HADM) implantation into wounds considered high risk, defined as either infected or with poor skin coverage. Patient demographics, preoperative risk factors and infection data, postoperative wound complications, and long-term results were collected.

RESULTS

Twenty-nine patients were identified in whom ADM was implanted into high-risk hernia defects. Forty-five percent developed a postoperative wound occurrence, with 31% requiring the wound to be either treated open or with a percutaneous drain. Ninety-six percent went on to heal without event. The follow-up evaluation averaged 182 days. Eighty-nine percent were repaired successfully with one surgery. Three recurrences have been identified.

CONCLUSIONS

The use of ADM allowed for successful primary closure in 90% of patients with intermediate- to long-term follow-up evaluation. A postoperative wound occurrence rate of 45% shows the use of this material in resisting infection. ADM can be used in ventral hernia repair in high-risk wounds with a high degree of success.

Acellular dermal matrix provides a good option for abdominal wall closure following small bowel transplantation: a case report

Following small bowel transplantation (SBTx), approximating the midline abdominal fascia can be problematic in patients with severely retracted abdominal cavities. We first report the use of acellular dermal matrix (ADM) for abdominal closure following living related SBTx. A 44-year-old woman with ultra-short gut syndrome secondary to multiple bowel resections received a 160-cm segmental intestinal graft from her daughter. The graft ileocolic vessels were anastomosed end to side to the inferior vena cava and distal aorta. A terminal ileostomy was fashioned because the patient had previous panproctocolectomy. The graft perfused well, and the laparotomy was primarily closed. On postoperative day 1, the patient required surgical exploration for evacuation of hematoma. Due to graft edema in a significantly retracted abdominal cavity, a 12x7 cm fascia defect was evident. Leaving the abdomen open or using a mesh was not entertained as options due to the high risk of infections. Primary closure under tension would also jeopardize the transplant, increasing the risk of thrombosis. The fascia defect was closed using a segment of ADM. The patient did well and went home on the postoperative day 11. At 2-year follow-up she is well and on oral diet without fascia defect or incisional hernia. This is the first report of the use of ADM for abdominal closure in patients receiving a SBTx. ADM is considered safe when used in contaminated sites and can allow primary closure of difficult wounds often seen in SBTx patients.

Successful treatment of burn and visceral injury combined with full-thickness loss of the abdominal wall after blast injury

A 29-year-old man was admitted to our institution 10 days after he had undergone an urgent exploratory laparotomy at a local army hospital after a terrorist bombing attack. On admission, deep second-degree and third-degree burns involving 25% of the upper and lower extremities were present, together with a 25 x 10-cm abdominal full-thickness blast injury defect on the left side, an infected eviscerated midline incision, and a colostomy on the right side of the abdomen. The patient underwent a second laparotomy, at which time the intraabdominal abscess was drained, and the abdominal cavity was irrigated with saline. A jejunal perforation was found and sutured. The abdominal cavity was left open and covered with a Bogota bag for temporary closure. On postburn day 18, the patient underwent débridment and grafting of the third-degree burns to the left and right arm and right lower extremities. After several débridment sessions (postburn days 16, 18, 20, 22, and 24), an abdominal skin release and reapproximation were performed (postburn day 26). On postburn day 36, split-thickness skin grafts were placed directly on the granulated tissue of the intestines and on a defect in the left flank and iliac regions. Postoperatively, the patient did well. He was discharged on postburn day 78 with all wounds well healed. In our opinion, temporary closure followed by direct application of meshed split-thickness skin grafts to exposed abdominal viscera represents a simple method of reconstruction that can be safely performed, with minimal risk, on critically ill patients.

Outcomes of allogenic acellular matrix therapy in treatment of diabetic foot wounds: an initial experience

The purpose of this study was to evaluate outcomes of persons with UT grade 2A neuropathic diabetic foot wounds treated with an acellular matrix. Data were abstracted for 17 consecutive patients with diabetes--76.5% males, aged 61.5 +/- 8.5 years with a mean glycated haemoglobin of 9.2 +/- 2.2% presenting for care at a large, multidisciplinary wound care centre. All patients received surgical debridement for their diabetic foot wounds and were placed on therapy consisting of a single application of an acellular matrix graft (GraftJacket; Wright Medical Technologies, Arlington, TN, USA) with dressing changes taking place weekly. Outcomes evaluated included time to complete wound closure and proportion of patients achieving wound closure in 20 weeks. Acellular matrix therapy was used as initial therapy and was sutured or stapled in place under a silicone-based non adherent dressing. Therapy was then followed by a moisture-retentive dressing until complete epithelialisation. In total, 82.4% of wounds measuring a mean 4.6 +/- 3.2 cm(2) healed in the 20-week evaluation period. For those that healed in this period, healing took place in a mean 8.9 +/- 2.7 weeks. We conclude that a regimen consisting of moist wound healing using an acellular matrix dressing may be a useful adjunct to appropriate diabetic foot ulcer care for deep, non-infected, non-ischaemic wounds. We await the completion of further trials in this area to confirm or refute this initial assessment.

Induction of profound hypothermia for emergency preservation and resuscitation allows intact survival after cardiac arrest resulting from prolonged lethal hemorrhage and trauma in dogs

BACKGROUND

Induction of profound hypothermia for emergency preservation and resuscitation (EPR) of trauma victims who experience exsanguination cardiac arrest may allow survival from otherwise-lethal injuries. Previously, we achieved intact survival of dogs from 2 hours of EPR after rapid hemorrhage. We tested the hypothesis that EPR would achieve good outcome if prolonged hemorrhage preceded cardiac arrest.

METHODS AND RESULTS

Two minutes after cardiac arrest from prolonged hemorrhage and splenic transection, dogs were randomized into 3 groups (n=7 each): (1) the cardiopulmonary resuscitation (CPR) group, resuscitated with conventional CPR, and the (2) EPR-I and (3) EPR-II groups, both of which received 20 L of a 2 degrees C saline aortic flush to achieve a brain temperature of 10 degrees C to 15 degrees C. CPR or EPR lasted 60 minutes and was followed in all groups by a 2-hour resuscitation by cardiopulmonary bypass. Splenectomy was then performed. The CPR dogs were maintained at 38.0 degrees C. In the EPR groups, mild hypothermia (34 degrees C) was maintained for either 12 (EPR-I) or 36 (EPR-II) hours. Function and brain histology were evaluated 60 hours after rewarming in all dogs. Cardiac arrest occurred after 124+/-16 minutes of hemorrhage. In the CPR group, spontaneous circulation could not be restored without cardiopulmonary bypass; none survived. Twelve of 14 EPR dogs survived. Compared with the EPR-I group, the EPR-II group had better overall performance, final neurological deficit scores, and histological damage scores.

CONCLUSIONS

EPR is superior to conventional CPR in facilitating normal recovery after cardiac arrest from trauma and prolonged hemorrhage. Prolonged mild hypothermia after EPR was critical for achieving intact neurological outcomes.

A new biocompatible material (Lyoplant) for the therapy of congenital abdominal wall defects: first experimental results in rats

Congenital abdominal wall defects are impressive and dramatic malformations. Common surgical therapy for omphalocele and gastroschisis is to place the herniated viscera back into the abdomen and to close the fascia. Small defects can be closed directly by surgical treatment. In large defects, resorbable and non-resorbable artificial materials are necessary to close the fascia. The aim of this study is to find out whether new biocompatible materials might be suitable for the treatment of such abdominal wall defects. A median laparotomy was performed in young Wistar rats with a body weight of 75-100 g. Then a full thickness defect was created by excising a 1.5 x 2.5 cm segment including fascia, muscles and peritoneum. These defects were then closed by implantation of a PTFE mesh (Dual-Mesh, n = 6), a PPP mesh (Prolene, n = 6) or a new biocompatible mesh (NBM; Lyoplant, n = 6). Each rat was examined daily after treatment. Bodyweight was determined and the possible development of a hernia was monitored. After 6 weeks, the abdomen was opened again. Adhesions to the intestine were measured and the abdominal wall was removed for histological and tensiometric examination. (1) Compared to the untreated controls, all animals showed physiologic growth and normal bodyweight curve. (2) Only in one rat (Prolene) did an abdominal hernia develop. (3) In contrast to PTFE and PPP mesh, NBM showed only minimal adhesion to the intestine. (4) Tensiometry revealed high stability for non-resorbable materials. However, the characteristics of NBM were very similar to untreated abdominal wall. Our initial results indicate that biocompatible materials can also be used for the therapy of congenital abdominal wall defects.

Early Aggressive Closure of the Open Abdomen

BACKGROUND

The aim of this series is to describe a new and aggressive approach to definitive closure of the open abdomen.

METHODS

A retrospective review of 37 patients who underwent definitive abdominal closure using a combination of vacuum pack, vacuum-assisted wound management and human acellular dermal matrix (HADM).

RESULTS

All patients' open abdomens were maintained with vacuum assisted wound management in attempts for primary closure. Once it was determined that the abdomen would not close primarily; it was closed with HADM and skin advancement. The mean duration of the open abdomen was 21.7 days (range 6-45), with an average of 127.78 cm of HADM, the largest number being 800 cm, with decreasing use of product later in the series. No major complications were seen with the repair. Superficial wound infection occurred with two patients that were easily treated with wet to dry dressing changes. No intraabdominal complications such as fistula or graft loss were seen. All patients left the hospital with an intact abdominal wall and skin. All 37 patients survived to discharge and were seen in follow-up within one month. No early hernia formation was seen at the one month follow up with the longest at three years. No abdominal wall complications were seen in subsequent follow up patients.

CONCLUSIONS

Early aggressive closure of the open abdomen is possible with a combination of vacuum pack, vacuum-assisted wound management and HADM. Short term results are promising and warrant further study.