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Background: The vertical rectus abdominis myocutaneous (VRAM) flap has emerged as the workhorse flap for perineal and pelvic reconstruction. The authors aimed to evaluate outcomes of the VRAM flap over a 20-year period and the role of mesh abdominal wall reinforcement following VRAM flap-based reconstruction., Methods: The authors conducted a retrospective review of all consecutive patients who underwent pelvic reconstruction with a VRAM flap between January of 2001 and March of 2021. Our primary outcome measure included recipient and donor surgical-site occurrences (SSOs)., Results: The authors identified a total of 546 patients (55% women) with a mean age of 58 years and mean body mass index of 27 kg/m 2 . Mesh was used at the time of VRAM reconstruction to reinforce the abdominal donor site in 36% of patients. Recipient SSOs occurred in 38% of patients, and donor SSOs occurred in 17% of patients. Hernia was identified in 9.9% of patients, and bulge developed in 6.4% of patients. The Cox proportional hazards regression model for hernia occurrence identified age, body mass index, tobacco use (hazard ratio, 2.03; 95% CI, 1.02 to 4.04), and use as an extended VRAM flap (hazard ratio, 2.13; 95% CI, 1.04 to 4.36). The use of mesh or component separation were not independent protective factors for hernia occurrence., Conclusions: The pedicled VRAM flap is versatile and is our preferred flap for reconstruction of pelvic and perineal defects. The use of mesh/component separation to allow for fascial closure was not shown to reduce donor-site hernia occurrence., Clinical Question/level of Evidence: Therapeutic, IV., (Copyright © 2023 by the American Society of Plastic Surgeons.)

Background: We evaluated the incidence of and the risk factors for readmission in patients who underwent abdominal wall reconstruction (AWR) using acellular dermal matrix (ADM) and assess whether readmission affects AWR long-term outcomes., Methods: A retrospective, single-center study of patients underwent AWR with ADM was conducted. The primary outcome was the incidence of unplanned readmission within 30 days after the initial discharge post-AWR. Secondary outcomes were surgical site occurrence (SSO) and hernia recurrence at follow-up., Results: Of 452 patients (mean age, 59 years; mean follow-up, 35 months), 29 (6.4%) were readmitted within 30 days. Most readmissions were due to SSO (44.8%) or wound infections (12.8%). The hernia recurrence rate was significantly higher in readmitted patients (17.2% vs 9.9%; P = 0.044). Wider defects, prolonged operative time, and coronary artery disease were independent predictors of readmission., Conclusions: Readmission is associated with hernia recurrence on long-term follow-up. SSO is the most common cause for readmission., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background: We hypothesized that elderly patients (≥65 years) experience worse outcomes following abdominal wall reconstruction (AWR) for hernia or oncologic resection., Methods: We included all consecutive patients who underwent complex AWR using acellular dermal matrix (ADM) between 2005 and 2015. Propensity score analysis was performed for risk adjustment in multivariable analysis and for one-to-one matching. The primary outcome was hernia recurrence; the secondary outcomes included surgical site occurrence (SSO) and bulging., Results: Mean follow-up for the 511 patients was 31.4 months; 184 (36%) patients were elderly. The elderly and non-elderly groups had similar rates of hernia recurrence (7.6% vs 10.1%, respectively; p = 0.43) and SSO (24.5% vs 23.5%, respectively; p = 0.82). Bulging occurred significantly more often in elderly patients (6.5% vs 2.8%, respectively; p = 0.04). After adjustment through the propensity score, which included 130 pairs, these results persisted., Conclusions: Contrary to our hypothesis, elderly patients did not have worse outcomes in AWR with ADM. Surgeons should not deny elderly patients AWR solely because of their age., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Background: The optimal strategy for abdominal wall reconstruction in the presence of a stomal-site hernia is unclear. We hypothesized that the rate of ventral hernia recurrence in patients undergoing a combined ventral hernia repair and stomal-site herniorraphy would not differ clinically from the ventral hernia recurrence rate in patients undergoing an isolated ventral hernia repair. We also hypothesized that bridged ventral hernia repairs result in worse outcomes compared with reinforced repairs, regardless of stomal hernia., Study Design: We retrospectively reviewed prospectively collected data from consecutive abdominal wall reconstructions performed with acellular dermal matrix (ADM) at a single center between 2000 and 2015. We compared patients who underwent a ventral hernia repair alone (AWR) and those who underwent both a ventral hernia repair and ostomy-associated herniorraphy (AWR+O). We conducted a propensity score matched analysis to compare the outcomes between the 2 groups. Multivariable Cox proportional hazards and logistic regression models were used to study associations between potential predictive or protective reconstructive strategies and surgical outcomes., Results: We included 499 patients (median follow-up 27.2 months; interquartile range [IQR] 12.4 to 46.6 months), 118 AWR+O and 381 AWR. After propensity score matching, 91 pairs were obtained. Ventral hernia recurrence was not statistically associated with ostomy-associated herniorraphy (adjusted hazard ratio [HR] 0.7; 95% CI 0.3 to 1.5; p = 0.34). However, the AWR+O group experienced a significantly higher percentage of surgical site occurrences (34.1%) than the AWR group (18.7%; adjusted odds ratio 2.3; 95% CI 1.4 to 3.7; p < 0.001). In the AWR group, there were significantly fewer ventral hernia recurrences when the repair was reinforced compared with bridged (5.3% vs 38.5%; p < 0.001)., Conclusions: There was no statistically significant difference in ventral hernia recurrence between the AWR and AWR+O groups. Bridging was associated with an increased rate of hernia recurrence and should be avoided if possible., (Copyright © 2016 American College of Surgeons. Published by Elsevier Inc. All rights reserved.)

Background: Long-term outcomes data for hernia recurrence rates after abdominal wall reconstruction (AWR) with acellular dermal matrix (ADM) are lacking. The aim of this study was to assess the long-term durability of AWR using ADM., Study Design: We studied patients who underwent AWR with ADM at a single center in 2005 to 2015 with a minimum follow-up of 36 months. Hernia recurrence was the primary end point and surgical site occurrence (SSO) was a secondary end point. The recurrence-free survival curves were estimated by Kaplan-Meier product limit method. Univariate and multivariable Cox proportional hazards regression models and logistic regression models were used to evaluate the associations of risk factors at surgery with subsequent risks for hernia recurrence and SSO, respectively., Results: A total of 512 patients underwent AWR with ADM. After excluding those with follow-up less than 36 months, 191 patients were included, with a median follow-up of 52.9 months (range 36 to 104 months). Twenty-six of 191 patients had a hernia recurrence documented in the study. The cumulative recurrence rates were 11.5% at 3 years and 14.6% by 5 years. Factors significantly predictive of hernia recurrence developing included bridged repair, wound skin dehiscence, use of human cadaveric ADM, and coronary disease; component separation was protective. In a subset analysis excluding bridged repairs and human cadaveric ADM patients, cumulative hernia recurrence rates were 6.4% by 3 years and 8.3% by 5 years. The crude rate of SSO was 25.1% (48 of 191). Factors significantly predictive of the incidence of SSO included at least 1 comorbidity, BMI ≥30 kg/m 2 , and defect width >15 cm., Conclusions: Use of ADM for AWR was associated with 11.5% and 14.6% hernia recurrence rates at 3- and 5-years follow-up, respectively. Avoiding bridged repairs and human cadaveric ADM can improve long-term AWR outcomes using ADM., (Copyright © 2016 American College of Surgeons. Published by Elsevier Inc. All rights reserved.)

Background: Previous studies suggest that bridged mesh repair for abdominal wall reconstruction may result in worse outcomes than mesh-reinforced, primary fascial closure, particularly when acellular dermal matrix is used. We compared our outcomes of bridged versus reinforced repair using ADM in abdominal wall reconstruction procedures., Methods: This retrospective study included 535 consecutive patients at our cancer center who underwent abdominal wall reconstruction either for an incisional hernia or for abdominal wall defects left after excision of malignancies involving the abdominal wall with underlay mesh. A total of 484 (90%) patients underwent mesh-reinforced abdominal wall reconstruction and 51 (10%) underwent bridged repair abdominal wall reconstruction. Acellular dermal matrix was used, respectively, in 98% of bridged and 96% of reinforced repairs. We compared outcomes between these 2 groups using propensity score analysis for risk-adjustment in multivariate analysis and for 1-to-1 matching., Results: Bridged repairs had a greater hernia recurrence rate (33.3% vs 6.2%, P < .001), a greater overall complication rate (59% vs 30%, P = .001), and worse freedom from hernia recurrence (log-rank P <.001) than reinforced repairs. Bridged repairs also had a greater rate of wound dehiscence (26% vs 14%, P = .034) and mesh exposure (10% vs 1%, P = .003) than mesh-reinforced abdominal wall reconstruction. When the treatment method was adjusted for propensity score in the propensity-score-matched pairs (n = 100), we found that the rates of hernia recurrence (32% vs 6%, P = .002), overall complications (32% vs 6%, P = .002), and freedom from hernia recurrence (68% vs 32%, P = .001) rates were worse after bridged repair. We did not observe differences in wound healing and mesh complications between the 2 groups., Conclusion: In our population of primarily cancer patients at MD Anderson Cancer Center bridged repair for abdominal wall reconstruction is associated with worse outcomes than mesh-reinforced abdominal wall reconstruction. Particularly when employing acellular dermal matrix, reinforced repairs should be used for abdominal wall reconstruction whenever possible., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Background: Many surgeons believe that primary fascial closure with mesh reinforcement should be the goal of abdominal wall reconstruction (AWR), yet others have reported acceptable outcomes when mesh is used to bridge the fascial edges. It has not been clearly shown how the outcomes for these techniques differ. We hypothesized that bridged repairs result in higher hernia recurrence rates than mesh-reinforced repairs that achieve fascial coaptation., Study Design: We retrospectively reviewed prospectively collected data from consecutive patients with 1 year or more of follow-up, who underwent midline AWR between 2000 and 2011 at a single center. We compared surgical outcomes between patients with bridged and mesh-reinforced fascial repairs. The primary outcomes measure was hernia recurrence. Multivariate logistic regression analysis was used to identify factors predictive of or protective for complications., Results: We included 222 patients (195 mesh-reinforced and 27 bridged repairs) with a mean follow-up of 31.1 ± 14.2 months. The bridged repairs were associated with a significantly higher risk of hernia recurrence (56% vs 8%; hazard ratio [HR] 9.5; p < 0.001) and a higher overall complication rate (74% vs 32%; odds ratio [OR] 3.9; p < 0.001). The interval to recurrence was more than 9 times shorter in the bridged group (HR 9.5; p < 0.001). Multivariate Cox proportional hazard regression analysis identified bridged repair and defect width > 15 cm to be independent predictors of hernia recurrence (HR 7.3; p < 0.001 and HR 2.5; p = 0.028, respectively)., Conclusions: Mesh-reinforced AWRs with primary fascial coaptation resulted in fewer hernia recurrences and fewer overall complications than bridged repairs. Surgeons should make every effort to achieve primary fascial coaptation to reduce complications., (Published by Elsevier Inc.)

Adhesions are common after intra-abdominal surgery and are associated with significant morbidity, including bowel obstruction, pain, and infertility. Abdominal wall reconstruction carries the risk of adhesion formation, notably to synthetic or bioprosthetic mesh. This article reviews the pathophysiology of adhesion formation, adhesion grading, and adhesions to synthetic and biologic mesh in vitro and clinically. Bioprosthetic mesh in vitro appears to elicit fewer lower-grade adhesions than synthetic mesh. However, direct comparisons in humans of adhesions with synthetic versus bioprosthetic mesh are lacking. Future studies are warranted to determine whether there are significant differences in clinical outcomes, especially regarding secondary complications from adhesions.

Background: Human acellular dermal matrix is used for ventral hernia repair, as it resists infection and remodels by means of surrounding tissue. However, the tissue source and impact of basement membrane on cell and vessel infiltration have not been determined. The authors hypothesized that musculofascia would be the primary tissue source of cells and vessels infiltrating into human acellular dermal matrix and that the basement membrane would inhibit infiltration., Methods: Fifty-six guinea pigs underwent inlay human acellular dermal matrix ventral hernia repair with the basement membrane oriented toward or away from the peritoneum. At postoperative weeks 1, 2, or 4, repair sites were completely excised. Histologic and immunohistochemical analyses were performed to quantify cell and vessel density within repair-site zones, including interface (lateral, beneath musculofascia) and center (beneath subcutaneous fat) zones. Cell and vessel quantities were compared as functions of zone, basement membrane orientation, and time., Results: Cellular and vascular infiltration increased over time universally. The interface demonstrated greater mean cell density than the center (weeks 1 and 2, p = 0.01 and p < 0.0001, respectively). Cell density was greater with the basement membrane oriented toward the peritoneum at week 4 (p = 0.02). The interface zone had greater mean vessel density than the center zone at week 4 (p < 0.0001). Orienting the basement membrane toward the peritoneum increased vessel density at week 4 (p = 0.0004)., Conclusions: Cellular and vascular infiltration into human acellular dermal matrix for ventral hernia repairs was greater from musculofascia than from subcutaneous fat, and the basement membrane inhibited cellular and vascular infiltration. Human acellular dermal matrix should be placed adjacent to the best vascularizing tissue to improve fibrovascular incorporation.

Background: Ventral hernia repair can be challenging, particularly in patients with serious comorbidity. Minimally invasive component separation with inlay bioprosthetic mesh (MICSIB) uses tunnel incisions for external oblique aponeurosis release. It preserves both the rectus abdominis myocutaneous perforator vessels that supply the overlying skin and the connection between the subcutaneous fat and anterior rectus sheath, thereby reducing subcutaneous dead space and potentially improving overlying skin flap vascularity. Inlay bioprosthetic mesh reinforces the musculofascial repair. This study evaluated surgical outcomes of the technique used to repair challenging ventral hernias in cancer patients., Methods: Data from all patients who underwent minimally invasive component separation with inlay bioprosthetic mesh abdominal wall reconstruction from 2007 to 2010 were analyzed. Surgical outcomes assessed included wound complications, hernia recurrence, and repair-site bulge/laxity., Results: Thirty-eight cancer patients (mean age, 63.3 years) considered at high risk for wound healing complications and hernia recurrence were included: 80 percent had preexisting medical comorbidities, 42 percent had infected or contaminated defects, and 26 percent had previous ventral hernia repairs. Despite the mean fascial defect size of 494 ± 229 cm2, only seven patients required a bridged repair. During a mean follow-up of 12.4 months, three patients (8 percent) required operative interventions, and nonoperative complications occurred in eight (21 percent). None developed a postoperative laxity/bulge; one (3 percent) had a hernia recurrence requiring operative repair., Conclusion: Minimally invasive component separation with inlay bioprosthetic mesh yields acceptable early outcomes in complex patients, likely because it reduces subcutaneous dead space, preserves the vascularity of overlying skin, and reinforces the musculofascial repair with mesh., Clinical Question/level of Evidence: Therapeutic, IV.

Background: Bioprosthetic mesh used for ventral hernia repair becomes incorporated into the musculofascial edge by cellular infiltration and vascularization. Adipose tissue-derived stem cells promote tissue repair and vascularization and may increase the rate or degree of tissue incorporation. The authors hypothesized that introducing these cells into bioprosthetic mesh would result in adipose tissue-derived stem cell engraftment and proliferation and enhance incorporation of the bioprosthetic mesh., Methods: Adipose tissue-derived stem cells were isolated from the subcutaneous adipose tissue of syngeneic Brown Norway rats, expanded in vitro, and labeled with green fluorescent protein. Thirty-six additional rats underwent inlay ventral hernia repair with porcine acellular dermal matrix. Two 12-rat groups had the cells (1.0 x 10(6)) injected directly into the musculofascial/porcine acellular dermal matrix interface after repair or received porcine acellular dermal matrix on which the cells had been preseeded; the 12-rat control group received no stem cells., Results: At 2 weeks, adipose tissue-derived stem cells in both stem cell groups engrafted, survived, migrated, and proliferated. Mean cellular infiltration into porcine acellular dermal matrix at the musculofascial/graft interface was significantly greater in the preseeded and injected stem cell groups than in the control group. Mean vascular infiltration of the porcine acellular dermal matrix was significantly greater in both stem cell groups than in the control group., Conclusions: Preseeded and injected adipose tissue-derived stem cells engraft, migrate, proliferate, and enhance the vascularity of porcine acellular dermal matrix grafts at the musculofascial/graft interface. These cells can thus enhance incorporation of porcine acellular dermal matrix into the abdominal wall after repair of ventral hernias.

Background: Porcine acellular dermal matrices (PADMs) have been used clinically for abdominal wall repair. The newer non-cross-linked PADMs, however, have not been directly compared with cross-linked PADMs. We hypothesized that chemical cross-linking affects the biologic host response to PADMs used to repair ventral hernias., Study Design: Fifty-eight guinea pigs underwent inlay repair of surgically created ventral hernias using cross-linked or non-cross-linked PADM. After animals were sacrificed at 1, 2, or 4 weeks, the tenacity of and surface area involved by adhesions to the repair sites were measured. Sections of the repair sites, including the bioprosthesis-musculofascia interface, underwent histologic analysis of cellular and vascular infiltration plus mechanical testing., Results: Compared with cross-linked PADM repairs, non-cross-linked PADM repairs had a significantly lower mean tenacity grade of adhesions at all timepoints and mean adhesion surface area at week 1. Mean cellular and vascular densities were significantly higher in non-cross-linked PADM at all timepoints. Cells and vessels readily infiltrated into the center of non-cross-linked PADM, but encapsulated cross-linked PADM, with a paucity of penetration into it. Mechanical properties were similar for the two PADMs (in isolation) at all timepoints; however, at the bioprosthesis-musculofascia interface, both elastic modulus and ultimate tensile strength were significantly higher at weeks 1 and 2 for non-cross-linked PADM., Conclusions: Non-cross-linked PADM is rapidly infiltrated with host cells and vessels; cross-linked PADM becomes encapsulated. Non-cross-linked PADM causes weaker adhesions to repair sites while increasing the mechanical strength of the bioprosthesis-musculofascia interface at early timepoints. Non-cross-linked PADM may have early clinical advantages over cross-linked PADM for bioprosthetic abdominal wall reconstruction., (Copyright 2010 American College of Surgeons. Published by Elsevier Inc. All rights reserved.)

Background: Transposition of well-vascularized flap tissue with or without implantable mesh is often required to repair full-thickness, composite abdominal wall defects. The authors hypothesized that the combination of an inlay of bioprosthetic mesh and a subtotal thigh flap would enable a reliable reconstruction for large, composite abdominal wall defects., Methods: The authors retrospectively reviewed data on patients who underwent repair of large, composite abdominal wall defects with bioprosthetic mesh and free or pedicled subtotal thigh flaps at a major cancer center from 2004 to 2007. Patient, defect, surgical technique, and outcome data were obtained from a prospectively maintained database and medical charts., Results: Seven patients who received eight subtotal thigh flaps (five pedicled and three free flaps with vein grafts to the femoral vessels) met the study criteria. Indications for reconstruction were tumor resection, enterocutaneous fistula, and abdominal wall osteoradionecrosis. All but one patient received preoperative radiotherapy (mean dose, 54.8 Gy). The musculofascial defect was repaired with a mean of 536.4 cm2 of bioprosthetic mesh. The mean subtotal thigh flap skin paddle size was 514 cm2. Complications included partial flap necrosis in one patient, a cerebrospinal fluid leak in one patient, partial split-thickness skin graft loss in two patients, a focal asymptomatic musculofascial repair-site bulge in one patient, and a hernia (not requiring surgery) in one patient. No bioprosthetic mesh infections, wound dehiscences, bowel obstructions, or seromas occurred (mean follow-up, 27.7 months)., Conclusion: Massive, composite abdominal wall defects can be repaired successfully with relatively minor complications using a combination of bioprosthetic mesh and subtotal thigh flaps.

Background: There is no consensus regarding the optimal technique for closure of the abdominal fascia after transverse rectus abdominis myocutaneous (TRAM) flap breast reconstruction. The authors reviewed outcomes with various techniques to identify the optimal one., Methods: The authors reviewed the charts of 81 consecutive patients who underwent TRAM flap breast reconstruction at their institution from 2002 to 2005. Various amounts of anterior rectus sheath fascia were harvested with the TRAM flap. Patients were divided into five groups based on fascia closure technique: (1) human acellular dermal matrix bridging inlay graft, (2) human acellular dermal matrix bridging inlay graft with primary closure of overlying anterior rectus sheath, (3) polypropylene mesh inlay graft, (4) polypropylene mesh inlay graft with primary closure, and (5) primary closure. For comparative analysis, three additional groups were created: all human acellular dermal matrix bridging inlay graft (groups 1 and 2), all mesh (groups 3 and 4), and all inlay (groups 1 and 3). Rates of donor-site complications were compared between groups., Results: Rates of abdominal bulge formation were as follows: overall, 14.8 percent; human acellular dermal matrix bridging inlay graft alone, 31 percent; human acellular dermal matrix bridging inlay graft plus primary closure, 20 percent; mesh alone, 10 percent; mesh plus primary closure, 5 percent; and primary closure alone, 5 percent. Rates of any complication (including bulge) were as follows: overall, 23.5 percent; human acellular dermal matrix bridging inlay graft alone, 42 percent; human acellular dermal matrix plus primary closure, 20 percent; mesh alone, 30 percent; mesh plus primary closure, 10 percent; and primary closure alone, 5 percent. Time to bulge formation was longer for all human acellular dermal matrix versus all mesh (p = 0.021. Time to any complication was longer for all inlay versus primary closure alone (p = 0.048), human acellular dermal matrix alone versus primary closure alone (p = 0.041)., Conclusions: For abdominal fascia repair after TRAM flap breast reconstruction, primary closure, when feasible, is preferable to an inlay graft; polypropylene mesh is preferable to human acellular dermal matrix if an inlay graft is required; adding primary closure to a mesh or human acellular dermal matrix inlay graft reduces bulge formation and other complications; and bulge occurs later with human acellular dermal matrix than with synthetic mesh.

Background: Patients who undergo pelvic floor resection as treatment for recurrent cancer following radiation therapy have increased rates of complications, particularly if permanent prosthetic mesh is used for reconstruction. Human acellular dermal matrix (HADM), commonly used for reconstruction in other torso locations, is associated with lower rates of complications (including infection, adhesions and cutaneous exposure) than synthetic mesh. We describe an effective technique to reconstruct the pelvic floor and perineum with HADM and thigh-based flaps following pelvic exenteration and radical vulvectomy., Case: A 75-year-old woman underwent radical resection of the pelvic floor and perineum to treat recurrent vulvar squamous cell carcinoma and osteoradionecrosis. The pelvic floor and perineal soft tissue defect were reconstructed with HADM (AlloDerm; LifeCell Corporation, Branchburg, NJ) and bilateral, thigh-based tissue flaps, respectively. Despite a large resection, previous irradiation therapy and bacterial contamination the wounds healed without complications., Conclusion: Reconstruction of pelvic floor defects using HADM is an option when wound conditions are unfavorable for the use of permanent prosthetic meshes.

Background: Synthetic mesh is used for chest wall reconstruction, but infection or exposure can occur and necessitate removal. Human acellular dermal matrix (AlloDerm) has been used to reconstruct musculofascial defects in the trunk with low infection and herniation rates. AlloDerm may have advantages over synthetic mesh for chest wall reconstruction. This study compared outcomes and repair strengths of AlloDerm to expanded polytetrafluoroethylene mesh used for repair of rib cage defects., Methods: A 3 x 3-cm, full-thickness, lateral rib cage defect was created in each rabbit and repaired with expanded polytetrafluoroethylene (n = 8) or acellular dermal matrix (n = 9). At 4 weeks, the animals were euthanized and evaluated for lung herniation/dehiscence, strength of adhesions between the implant and intrapleural structures, and breaking strength of the implant materials and the implant-fascia interface. Tissue sections were analyzed with histologic and immunohistochemical staining to evaluate cellular infiltration and vascularization., Results: No herniation or dehiscence occurred with either material. The incidence and strength of adhesions was similar between materials. The mean breaking strength of the AlloDerm-fascia interface (14.5 +/- 8.9 N) was greater than the expanded polytetrafluoroethylene-fascia interface (8.7 +/- 4.4 N; p = 0.027) and similar to the rib-intercostal-rib interface of the contralateral native chest wall (14.0 +/- 5.6 N). The AlloDerm grafts became infiltrated with cells and vascularized after implantation., Conclusions: AlloDerm used for chest wall reconstruction results in greater implant-defect interface strength than expanded polytetrafluoroethylene. The ability of AlloDerm to become vascularized and remodeled by autologous cells and to resist infection may be advantageous for chest wall reconstruction.

Ventral hernia repair often includes the use of structural prosthetic materials, such as polypropylene mesh, that can induce dense abdominal adhesions to peritoneal structures. AlloDerm (LifeCell Corp., Branchburg, N.J.), a commercially available decellularized human dermal analogue with its native basement membrane components intact, is gradually revascularized and replaced with autologous tissue after implantation. The authors hypothesized that AlloDerm integrated with polypropylene mesh would reduce adhesions and provide a biodegradable scaffold to generate an autologous vascularized tissue layer separating the abdominal viscera from the mesh. Ventral hernia defects (3 x 1 cm) in 19 guinea pigs were repaired using an inlay technique with polypropylene mesh alone (n = 6) or with composite implants constructed by integrating polypropylene mesh and AlloDerm with its basement membrane surface oriented toward (polypropylene/AlloIn, n = 7) or away from (polypropylene/ AlloOut, n = 6) the peritoneal cavity. At 4 weeks, the authors determined the amount of mesh implant surface area covered by adhesions, the strength of the adhesions [graded from 0 (none) to 3], and the incidence of bowel adhesions. Histologic analyses were performed on full-thickness tissue sections from the repair sites. The mean surface areas affected by adhesions and mean adhesion strength were significantly lower in the polypropylene/AlloIn (area, 12.4 percent; mean grade, 1.0) and polypropylene/AlloOut (area, 9.5 percent; mean grade, 0.5) groups than in the polypropylene group (area, 79.5 percent; mean grade, 2.9); there were no such differences between the polypropylene/AlloIn and polypropylene/AlloOut groups. The bowel was adherent to 67 percent of polypropylene repairs and 0 percent of the composite mesh repairs. The AlloDerm was remodeled to form a vascularized tissue layer beneath the mesh in composite repairs, unlike the significantly thinner, dense scar layer that formed in the polypropylene repairs. Immunohistochemical labeling for factor VIII showed neovascularization throughout the AlloDerm. The AlloDerm thus functioned as a biodegradable tissue scaffold, guiding the formation of a thick, well-vascularized tissue layer separating the polypropylene mesh from intraperitoneal structures. This significantly reduced both the amount of surface area covered by adhesions and adhesion strength. Basement membrane orientation had no effect. Composite mesh implants composed of structural prosthetic materials integrated with AlloDerm may have useful clinical applications for abdominal wall reconstruction by reducing adhesions and providing a vascularized tissue layer to separate and protect the peritoneal structures from polypropylene mesh fibers.

Structural biomaterials can restore abdominal wall integrity but may cause adhesions to the underlying viscera. Collagen-glycosaminoglycan (CG) matrices induce the formation of connective tissue and may reduce adhesion formation to permanent biomaterials such as polypropylene (PP) mesh. Composite implants were created by interposing PP mesh within a porous CG matrix created composite implants. The implants were cross-linked with glutaraldehyde one group (CG-G/PP) or left untreated (CG-nG/PP) and compared to PP mesh. At 4 weeks, the abdominal wall was assessed for the degree of adhesions. The composite implants developed a nascent connective tissue-like structure that reduced adhesions to the bowel. The thickest connective tissue developed in the CG-G/PP group (0.7 +/- 0.1 mm) and thinnest in the PP mesh (0.05 +/- 0.01 mm). The surface area covered with adhesions was greatest in the PP group (72 +/- 17%) compared with the CG-G/PP group (28 +/- 15%) or the CG-nG/PP group (21 +/- 8%). Bowel preferentially adhered to the PP mesh, whereas omentum had some adherence to all constructs. Integrating a biodegradable extracellular matrix analog with a permanent structural biomaterial reduced adhesions in this animal model. Alterations in cross-linking of the CG matrix altered the biological response. This technology may be useful in reconstructive surgery by reducing adhesion formation, while maintaining the strength of permanent structural biomaterials., (Copyright 2000 John Wiley & Sons, Inc.)