Comparison of acellular dermal matrix and synthetic mesh for lateral chest wall reconstruction in a rabbit model

Long-Term Outcome of Chest Wall and Diaphragm Repair with Biological Materials

INTRODUCTION

 Chest wall and/or diaphragm reconstruction aims to preserve, restore, or improve respiratory function; conserve anatomical cavities; and upkeep postural and upper extremity support. This can be achieved by utilizing a wide range of different grafts made of synthetic, biological, autologous, or bioartificial materials. We aim to review our experience with decellularized bovine pericardium as graft in the past decade.

PATIENTS AND METHODS

 We conducted a retrospective analysis of patients who underwent surgical chest wall and/or diaphragm repair with decellularized bovine pericardium between January 1, 2012 and January 13, 2022 at our institution. All records were screened for patient characteristics, intra-/postoperative complications, chest tube and analgesic therapy duration, length of hospital stay, presence or absence of redo procedures, as well as morbidity and 30-day mortality. We then looked for correlations between implanted graft size and postoperative complications and gathered further follow-up information at least 2 months after surgery.

RESULTS

 A total of 71 patients either underwent isolated chest wall (n = 51), diaphragm (n = 12), or pericardial (n = 4) resection and reconstruction or a combination thereof. No mortality was recorded within the first 30 days. Major morbidity occurred in 12 patients, comprising secondary respiratory failure requiring bronchoscopy and invasive ventilation in 8 patients and secondary infections and delayed wound healing requiring patch removal in 4 patients. There was no correlation between the extensiveness of the procedure and extubation timing (chi-squared test, p = 0.44) or onset of respiratory failure (p = 0.27).

CONCLUSION

 A previously demonstrated general viability of biological materials for various reconstructive procedures appears to be supported by our long-term results.

Biologic versus synthetic prosthesis for chest wall reconstruction: a matched analysis

OBJECTIVES

The aim of this study was to compare postoperative outcomes between biologic and synthetic reconstructions after chest wall resection in a matched cohort.

METHODS

All patients who underwent reconstruction after full-thickness chest wall resection from 2000 to 2022 were reviewed and stratified by prosthesis type (biologic or synthetic). Biologic prostheses were of biologic origin or were fully absorbable and incorporable. Integer matching was performed to reduce confounding. The study end point was surgical site complications requiring reoperation. Multivariable analysis was performed to identify associated risk factors.

RESULTS

In total, 438 patients underwent prosthetic chest wall reconstruction (unmatched: biologic, n = 49; synthetic, n = 389; matched: biologic, n = 46; synthetic, n = 46). After matching, the median (interquartile range) defect size was 83 cm2 (50-142) for the biologic group and 90 cm2 (48-146) for the synthetic group (P = 0.97). Myocutaneous flaps were used in 33% of biologic reconstructions (n = 15) and 33% of synthetic reconstructions (n = 15) in the matched cohort (P = 0.99). The incidence of surgical site complications requiring reoperation was not significantly different between biologic and synthetic reconstructions in the unmatched (3 [6%] vs 29 [7%]; P = 0.99) and matched (2 [4%] vs 4 [9%]; P = 0.68) cohorts. On the multivariable analysis, operative time [adjusted odds ratio (aOR) = 1.01, 95% confidence interval (CI), 1.00-1.01; P = 0.006] and operative blood loss (aOR = 1.00, 95% CI, 1.00-1.00]; P = 0.012) were associated with higher rates of surgical site complications requiring reoperation; microvascular free flaps (aOR = 0.03, 95% CI, 0.00-0.42; P = 0.024) were associated with lower rates.

CONCLUSIONS

The incidence of surgical site complications requiring reoperation was not significantly different between biologic and synthetic prostheses in chest wall reconstructions.

Physician antibiotic hydration preferences for biologic antibacterial envelopes during cardiac implantable device procedures

Background

Cardiac implantable electronic device (CIED) infection is a potentially serious complication of CIED procedures. Infection risk mitigation includes using guideline-recommended pre-operative intravenous antibacterial prophylaxis (IV ABX). The use of antibiotic-eluting CIED envelopes has also been shown to reduce infection risk. The relationship between and potential benefits associated with guideline-recommended IV ABX in combination with antibacterial envelopes have not been characterized.

Methods

Biologic envelopes made from non-crosslinked extracellular matrix (ECM) were implanted into 1,102 patients receiving CIEDs. The implanting physician decided patient selection for using a biologic envelope and envelope hydration solution. Observational data was analyzed on IV ABX utilization rates, antibacterial envelope usage, and infection outcomes.

Results

Overall compliance with IV ABX was 96.6%, and most patients received a biologic envelope hydrated in antibiotics (77.1%). After a mean follow-up of 223 days, infection rates were higher for sites using IV ABX <80% of the time vs. sites using ≥80% (5.6% vs. 0.8%, p = 0.008). Physicians demonstrated preference for hydration solutions containing gentamicin in higher-risk patients, which was found by multivariate analysis to be associated with a threefold reduction in infection risk (OR 3.0, 95% CI, 1.0-10.0).

Conclusion

These findings suggest that use of antibiotics, particularly gentamicin, in biologic envelope hydration solution may reduce infection risk, and use of antibacterial envelopes without adjunct IV ABX may not be sufficient to reduce CIED infections.

Clinical trial registration

[https://clinicaltrials.gov/], identifier [NCT02530970].

Risk profiles and outcomes of patients receiving antibacterial cardiovascular implantable electronic device envelopes: A retrospective analysis

BACKGROUND

Cardiovascular implantable electronic devices (CIEDs) are implanted in an increasing number of patients each year, which has led to an increase in the risk of CIED infection. Antibacterial CIED envelopes locally deliver antibiotics to the implant site over a short-term period and have been shown to reduce the risk of implant site infection. These envelopes are derived from either biologic or non-biologic materials. There is a paucity of data examining patient risk profiles and outcomes from using these envelope materials in the clinical setting and comparing these results to patients receiving no envelope with their CIED implantation.

AIM

To evaluate risk profiles and outcomes of patients who underwent CIED procedures with an antibacterial envelope or no envelope.

METHODS

After obtaining Internal Review Board approval, the records of consecutive patients who underwent a CIED implantation procedure by a single physician between March 2017 and December 2019 were retrospectively collected from our hospital. A total of 248 patients within this period were identified and reviewed through 12 mo of follow up. The CIED procedures used either no envelope (n = 57), a biologic envelope (CanGaroo^®, Aziyo Biologics) that was pre-hydrated by the physician with vancomycin and gentamicin (n = 89), or a non-biologic envelope (Tyrx™, Medtronic) that was coated with a resorbable polymer containing the drug substances rifampin and minocycline by the manufacturer (n = 102). Patient selection for receiving either no envelope or an envelope (and which envelope to use) was determined by the treating physician. Statistical analyses were performed between the 3 groups (CanGaroo, Tyrx, and no envelope), and also between the No Envelope and Any Envelope groups by an independent, experienced biostatistician.

RESULTS

On average, patients who received any envelope (biologic or non-biologic) were younger (70.7 ± 14.0 vs 74.9 ± 10.6, P = 0.017), had a greater number of infection risk factors (81.2% vs 49.1%, P < 0.001), received more high-powered devices (37.2% vs 5.8%, P = 0.004), and were undergoing more reoperative procedures (47.1% vs 0.0%, P < 0.001) than patients who received no envelope. Between the two envelopes, biologic envelopes tended to be used more often in higher risk patients (84.3% vs 78.4%) and reoperative procedures (62.9% vs 33.3%) than non-biologic envelopes. The rate of CIED implant site pocket infection was low (any envelope 0.5% vs no envelope 0.0%) and was statistically equivalent between the two envelope groups. Other reported adverse events (lead dislodgement, lead or pocket revision, device migration or erosion, twiddler’s syndrome, and erythema/fever) were low and statistically equivalent between groups (biologic 2.2%, non-biologic 3.9%, no envelope 1.8%).

CONCLUSION

CIED infection rates for biologic and non-biologic antibacterial envelopes are similar. Antibacterial envelopes may benefit patients who are higher risk for infection, however additional studies are warranted to confirm this.

Intra-articular injection of decellularized extracellular matrices in the treatment of osteoarthritis in rabbits

Background

We investigated the role of decellularized cartilage matrix in osteoarthritis to seek a new treatment for this disease.

Methods

Knee cartilage from rabbits was decellularized and the degree of decellularization was assessed. A grinder was used to turn acellular cartilage into particles, which were then used in a suspension. Thirty New Zealand white rabbits were subjected to an operation on their anterior cruciate ligament for the osteoarthritis model. The success of the animal model of osteoarthritis was evaluated using results from six rabbits. The remaining 24 rabbits were randomly divided into four groups (groups A, B, C, and D). Rabbits in groups A, B, C, and D were injected with 200 µl of normal saline, 200 µl of 10% (w/v) cartilage decellularized suspension, 200 µl of 20% (w/v) cartilage decellularized suspension, and 200 µl of 40% (w/v) cartilage decellularized suspension into the knee joints, respectively. Macroscopic and microscopic assessments were performed three months after surgery to assess the degree of osteoarthritic changes.

Results

Histological and biochemical analysis revealed that the cartilage decellularized matrix removed cells after decellularization but retained components of collagen and glycosaminoglycan. Group A exhibited the most significant changes from osteophyte and cartilage erosion, which was macroscopically observable on the surface of the femoral cartilage. HE staining in group A revealed damage to the cartilage surface, disorganized chondrocytes, and spontaneous fibrocartilage formation. Safranin O-fast green staining revealed a cavity formed at the osteochondral junction in group A that did not appear in other groups.

Conclusion

Our study shows that decellularized cartilage matrix has a certain therapeutic effect on osteoarthritis and provides new insights in the treatment of osteoarthritis.

Synthetic Mesh Versus Acellular Dermal Matrix for Oncologic Chest Wall Reconstruction: A Comparative Analysis

BACKGROUND

Management of chest wall defects after oncologic resection is challenging due to multifactorial etiologies. Traditionally, skeletal stabilization in chest wall reconstruction (CWR) was performed with synthetic prosthetic mesh. The authors hypothesized that CWR for oncologic resection defects with acellular dermal matrix (ADM) is associated with a lower incidence of complications than synthetic mesh.

METHODS

Consecutive patients who underwent CWR using synthetic mesh (SM) or ADM at a single center were reviewed. Only oncologic defects involving resection of at least one rib and reconstruction with both mesh and overlying soft tissue flaps were included in this study. Patients' demographics, treatment factors, and outcomes were prospectively documented. The primary outcome measure was surgical-site complications (SSCs). The secondary outcomes were specific wound-healing events, cardiopulmonary complications, reoperation, and mortality.

RESULTS

This study investigated 146 patients [95 (65.1%) with SM; 51 (34.9%) with ADM] who underwent resection and CWR of oncologic defects. The mean follow-up period was 29.3 months (range 6-109 months). The mean age was 51.5 years, and the mean size of the defect area was 173.8 cm². The SM-CWR patients had a greater number of ribs resected (2.7 vs. 2.0 ribs; p = 0.006) but a similar incidence of sternal resections (29.5% vs. 23.5%; p = 0.591) compared with the ADM-CWR patients. The SM-CWR patients experienced significantly more SSCs (32.6% vs. 15.7%; p = 0.027) than the ADM-CWR patients. The two groups had similar rates of specific wound-healing complications. No differences in mortality or reoperations were observed.

CONCLUSIONS

The ADM-CWR patients experienced fewer SSCs than the SM-CWR patients. Surgeons should consider selectively using ADM for CWR, particularly in patients at higher risk for SSCs.

Effect of Biologic Material Reinforcement on Surgical Anastomosis After Gastrectomy-A Pilot Study

Background: Acellular dermal matrix is a biologic material derived from the skin of human cadaveric donors. It has been used successfully in the past to reduce complications in breast surgery and hernia repair. This investigation was aimed at assessing the feasibility of using acellular dermal matrix to support the anastomosis after gastrectomy with the aim of reducing anastomotic site leakage complications. Methods: Patients were randomly assigned to standard anastomotic reconstruction (control arm) or anastomotic reconstruction with acellular dermal matrix reinforcement (intervention arm). Surgical outcomes related to anastomotic complications were collected. Because actual anastomotic leaks found on imaging studies are infrequent and thus require a very high number of patient recruitment to detect statistically significant difference between the two groups, in this pilot investigation other clinical and laboratory measures that have been shown to correlate to or predict anastomotic leaks were also collected. Each surgical outcome was compared. Results: A total of 94 patients (intervention arm: 50, control arm: 44), were included in the analysis. Two patients in the control arm (4.55%) and one patient in the intervention arm (2.00%) experienced anastomotic leakage (p = 0.598), a difference without statistical significance. However, average postoperative C-reactive protein (CRP) levels and NUn scores, both of which have been shown to reflect likelihood of progressing to anastomotic leakage, were significantly lower for the intervention arm. The control arm showed an average CRP level of 128.77 mg/dL (SD: 97.08) while the intervention arm showed 77.38 mg/dL (SD: 49.08, p = 0.049). Conclusions: Leakage rate reduction with acellular dermal matrix reinforcement of anastomotic site was not detected in this investigation. However, postoperative inflammation levels and numerical predictors of anastomotic leakage development were significantly lower with acellular dermal matrix reinforcement of surgical anastomosis. This finding is worthy of further investigation, as reduction of inflammation with anastomotic site reinforcement is a novel finding, and more in-depth research may lead to discoveries on the physiologic role of the surgical anastomosis in post-gastrectomy patients. In addition, lower CRP and NUn scores for the intervention arm suggest potential for larger studies to detect reduction in clinical leak rates after acellular dermal matrix reinforcement.

Chest Wall Reconstruction with Porcine Acellular Dermal Matrix (Strattice) and Autologous Tissue Transfer for High Risk Patients with Chest Wall Tumors

Supplemental Digital Content is available in the text.

Background:

Tenets of chest wall reconstruction for malignancy are well known; however, the insertion of synthetic prosthetic material to achieve rigid and nonrigid skeletal reconstruction could be associated with more complications including infection and extrusion especially in high risk patients. This includes fungating, infected tumors, previous radiotherapy, scars, smoking, diabetes, and morbid obesity. Bioprosthesis Acelluar Dermal Matrix Strattice would be a substitute to resist infection and provide stable coverage.

Methods:

A retrospective data analysis study on 8 high-risk patients who underwent chest wall resection and reconstruction with bioprosthesis (Strattice) with/without titanium plates in the period between 2012 and 2017 was performed. Patient’s demographics, risk factors, clinico-pathological, radiological, operative details, adjuvant therapy, postoperative morbidity, and follow-up data were recorded.

Results:

Sarcoma was the pathology in 7 and recurrent breast cancer in 1 with age range from 21 to 71 years (mean, 50) and preponderance of female patients (n = 5). Defects were located anterior/anterolateral with size ranging from 270 to 1,050 cm² (mean, 511). Reconstruction was performed using Strattice only in 4 patients, whereas in 4 it was combined with titanium plates. All patients required flap reconstruction (3 pedicled and 5 free). The follow-up ranged from 9 to 52 months (mean, 24.8). Minor complications occurred in 2 patients; however, good functional outcome was achieved in all.

Conclusion:

Strattice would act as a safe alternative modality for chest wall reconstruction to resist infection in high-risk patients with extensive defects. It should be considered as a valuable tool in the armamentarium of chest wall reconstruction.

Reconstruction of the Thoracic Wall With Biologic Mesh After Resection for Chest Wall Tumors: A Presentation of a Case Series and Original Technique

INTRODUCTION

Synthetic materials have traditionally been used for tissue reconstruction in thoracic surgery. New biomaterials have been tested in other areas of surgery with good results. Non-cross-linked swine dermal collagen prosthesis has been used to reconstruct musculofascial defects in the trunk with low infection and herniation rate.

MATERIAL AND METHODS

Retrospectively, we analyze our initial experience of chest wall reconstruction on large defects using a non-cross-linked swine dermal collagen matrix mesh with a thickness of 1.4 mm. A total of 11 consecutive patients were included. Preoperative, intraoperative, and postoperative data were taken into consideration.

RESULTS

Eleven sarcoma patients with a mean age of 58.25 ± 12.9 years underwent chest wall resections. Complete thoracic wall defects ranged from 6 · 9 to 16 · 25 cm in size. In all cases, we used a porcine collagen matrix mesh, and in all patients, it was covered by transposition of myocutaneous flap. The complications occurred in 5 (45%) patients, 1 (9%) pneumonia, 1 atrial fibrillation (9%), and 3 (27%) wound healing difficulty because of hematoma or infection. There was no respiratory impairment, and the pulmonary function (total lung capacity, vital capacity, and forced expiratory volume in 1 second) was not statistically different before and after surgery. The 30-day mortality was 0%, 1-year mortality and 2-year mortality was 27.2%. The collagen material resulted in a durable and good to excellent chest wall stability in clinical follow-ups, and on computer tomography scans spanning over 2 years.

CONCLUSION

Non-cross-linked acellular porcine dermal collagen matrix is a feasible and reliable biological patch material for reconstruction of the thoracic wall. Excellent wound healing, long-term stability, low complication, and good pulmonary function are achieved even in large defects.

Evaluation of Sidestream Darkfield Microscopy for Real-Time Imaging Acellular Dermal Matrix Revascularization

BACKGROUND

Acellular dermal matrices (ADMs) serve as a regenerative framework for host cell integration and collagen deposition to augment the soft tissue envelope in ADM-assisted breast reconstruction-a process dependent on vascular ingrowth. To date noninvasive intra-operative imaging techniques have been inadequate to evaluate the revascularization of ADM.

METHODS

We investigated the safety, feasibility, and efficacy of sidestream darkfield (SDF) microscopy to assess the status of ADM microvascular architecture in 8 patients at the time of tissue expander to permanent implant exchange during 2-stage ADM-assisted breast reconstruction. The SDF microscopy is a handheld device, which can be used intraoperatively for the real-time assessment of ADM blood flow, vessel density, vessel size, and branching pattern. The SDF microscopy was used to assess the microvascular architecture in the center and border zone of the ADM and to compare the native, non-ADM-associated capsule in each patient as a within-subject control.

RESULTS

No incidences of periprosthetic infection, explantation, or adverse events were reported after SDF image acquisition. Native capsules demonstrate a complex, layered architecture with an average vessel area density of 14.9 mm/mm and total vessel length density of 12.3 mm/mm. In contrast to native periprosthetic capsules, ADM-associated capsules are not uniformly vascularized structures and demonstrate 2 zones of microvascular architecture. The ADM and native capsule border zone demonstrates palisading peripheral vascular arcades with continuous antegrade flow. The central zone of the ADM demonstrates punctate perforating vascular plexi with intermittent, sluggish flow, and intervening 2- to 3-cm watershed zones.

CONCLUSIONS

Sidestream darkfield microscopy allows for real-time intraoperative assessment of ADM revascularization and serves as a potential methodology to compare revascularization parameters among commercially available ADMs. Thr SDF microscopy demonstrates that the periprosthetic capsule in ADM-assisted implant-based breast reconstruction is not a uniformly vascularized structure.

Experimental study of ASCs combined with POC-PLA patch for the reconstruction of full-thickness chest wall defects

To explore the repairing effect of combination of adipose stem cells (ASCs) and composite scaffolds on CWR, the electrospun Poly 1, 8-octanediol-co-citric acid (POC)-poly-L-lactide acid (PLA) composite scaffolds were prepared, followed by in vitro and in vivo biocompatibility evaluation of the scaffolds. Afterwards, ASCs were seeded on POC-PLA to construct the POC-PLA-ASCs scaffolds, and the POC-PLA, POC-PLA-ASCs, and traditional materials expanded polytetrafluoroethylene (ePTFE) were adopt for CWR in New Zealand white (NZW) rabbit models. As results, the POC-PLA-ASCs patches possessed good biocompatibility as the high proliferation ability of cells surrounding the patches. Rabbits in POC-PLA-ASCs groups showed better pulmonary function, less pleural adhesion, higher degradation rate and more neovascularization when compared with that in other two groups. The results of western blot indicated that POC-PLA-ASCs patches accelerated the expression of VEGF and Collagen I in rabbit models. From the above, our present study demonstrated that POC-PLA material was applied for CWR successfully, and ASCs seeded on the sheets could improve the pleural adhesions and promote the reparation of chest wall defects.

Materials and techniques in chest wall reconstruction: a review

Extensive chest wall resection and reconstruction are a challenging procedure that requires a multidisciplinary approach, including input from thoracic surgeon, plastic surgeon and oncologist. In particular chest wall neoplastic pathology is associated with high surgical morbidity and can result in full thickness defects hard to reconstruct. The goals of a successful chest wall reconstruction are to restore the chest wall rigidity, preserve pulmonary mechanic and protect the intrathoracic organs minimizing the thoracic deformity. In case of large full thickness defects synthetic, biologic or composite meshes can be used, with or without titanium plate to restore thoracic cage rigidity as like as more recently the use of allograft to reconstruct the sternum. After skeletal stability is established full tissue coverage can be achieved using direct suture, skin graft or local advancement flaps, pedicled myocutaneous flaps or free flaps. The aim of this article is to illustrate the indications, various materials and techniques for chest wall reconstruction with the goal to obtain the best chest wall rigidity and soft tissue coverage.

Important considerations in chest wall reconstruction

Chest wall reconstruction represents one of the most challenging tasks in plastic surgery. Over the past several decades, a more profound understanding of surgical anatomy and physiology along with tremendous advances in surgical technique have resulted in substantial improvements in postoperative outcomes. Conceptually, the reconstructive goals include dead space obliteration, restoration of skeletal stability with protection of intrathoracic structures, and stable soft tissue coverage. Ideally, these goals are achieved with minimal aesthetic deformity. J. Surg. Oncol. 2016;113:913-922. © 2016 Wiley Periodicals, Inc.

Porcine acellular dermal matrix (PADM) vascularises after exposure in open necrotic wounds seen after complex hernia repair

Biological alternatives to synthetic meshes are increasingly utilised in complex abdominal wall reconstruction. There is a lack of evidence demonstrating that non-cross-linked porcine acellular dermal matrix vascularizes and integrates with human tissue in suboptimal wound conditions. We aimed to evaluate these properties in Strattice™ (Life Cell Inc., Branchburg, NJ) following ventral hernia repair. A retrospective review of patients with high-risk ventral hernia repair utilising Strattice™ as an onlay after open component separation was conducted. Patients with postoperative wound exploration and exposure of the onlay were included in this review. One patient underwent punch biopsy for histological analysis. Eleven patients with wound complications necessitating postoperative debridement and exposure of Strattice™ onlay were identified. The onlay was partially debrided in two cases, and one case required complete excision. Vascularisation was clinically evident in 10 of 11 cases (91%) as demonstrated by the presence of granulation tissue and/or the ability to support a skin graft. Histological analysis of one onlay 3 months postoperatively showed neovascularisation and collagen remodelling with minimal inflammatory response. Strattice™ demonstrated resistance to rejection, ability to undergo vascularisation and incorporation into host tissues in sub-optimal wound conditions following ventral hernia repair.

Chest Wall Reconstruction: Evolution Over a Decade and Experience With a Novel Technique for Complex Defects

BACKGROUND

Chest wall reconstruction (CWR) with biologic matrices has gained popularity over the last decade; however, data on this topic remain sparse. The aim of this study is to review the different methods and materials used for CWR while reviewing and highlighting a novel approach using a biologic inlay and synthetic onlay technique for larger, complex high-risk defects.

METHODS

A retrospective review was performed of all patients who underwent full thickness chest wall resection and reconstruction during a 10-year period. Patient characteristics, comorbidities, operative data, as well as postoperative wound complications and outcomes were reviewed. Different reconstructive methods and materials were reviewed and compared.

RESULTS

From December 2003 to January 2014, a total of 81 patients underwent CWR. The indications for resection/reconstruction included oncologic in 49 patients (60.5%), desmoids tumors in 10 (12.3%), bronchopleural fistula in 3 (3.7%), infection in 7 (8.6%), and anatomic deformity in 7 (8.6%) patients. Synthetic and/or acellular dermal matrices (ADM) reconstruction was used in 59 patients (10 biologic, 22 synthetic, and 27 biologic ADM inlay/synthetic onlay combination). On average, 2.5, 3.5, and 3.6 ribs were resected in the biologic, synthetic, and combination group, respectively (P = 0.1). A greater number of patients in the combination group had a history of chemotherapy and/or radiation therapy (P = 0.03) than the synthetic or biologic alone groups. Risk analysis demonstrated an association between the number of ribs resected and postoperative chest wall complications. The incidence of chest wall/wound complications in the synthetic, combination, and biologic groups was 31.8%, 22.2%, and 10%, respectively (P = 0.47).

CONCLUSIONS

In the largest single institution study comparing the use of different reconstructive materials, including ADM in CWR, the authors demonstrate that a biologic inlay/synthetic onlay may be used effectively for high-risk, large complex defects. Early outcomes with this technique are promising. The authors believe this combination highlights benefits from both materials because the ADM facilitates tissue ingrowth and revascularization, whereas the synthetic component provides structural durability. Additional studies with larger sample sizes are necessary to further explore the benefits of the combination technique to determine if outcomes are better than either material alone when used to reconstruct high-risk wounds after larger resections.

The impact of chemotherapy and radiation therapy on the remodeling of acellular dermal matrices in staged, prosthetic breast reconstruction

BACKGROUND

An acellular dermal matrix will typically incorporate, in time, with the overlying mastectomy skin flap. This remodeling process may be adversely impacted in patients who require chemotherapy and radiation, which influence neovascularization and cellular proliferation.

METHODS

Multiple biopsy specimens were procured from 86 women (n = 94 breasts) undergoing exchange of a tissue expander for a breast implant. These were divided by biopsy location: submuscular capsule (control) as well as superiorly, centrally, and inferiorly along the paramedian acellular dermis. Specimens were assessed for cellular infiltration, cell type, fibrous encapsulation, scaffold degradation, extracellular matrix deposition, neovascularization, mean composite remodeling score, and type I and III collagen. Patients were compared based on five oncologic treatment groups: no adjuvant therapy (untreated), neoadjuvant chemotherapy with or without radiation, and chemotherapy with or without radiation.

RESULTS

Biopsy specimens were procured 45 to 1805 days after implantation and demonstrated a significant reduction in type I collagen over time. Chemotherapy adversely impacted fibrous encapsulation (p = 0.03). Chemotherapy with or without radiation adversely impacted type I collagen (p = 0.02), cellular infiltration (p < 0.01), extracellular matrix deposition (p < 0.04), and neovascularization (p < 0.01). Radiation exacerbated the adverse impact of chemotherapy for several remodeling parameters. Neoadjuvant chemotherapy also caused a reduction in type I (p = 0.01) and III collagen (p = 0.05), extracellular matrix deposition (p = 0.03), and scaffold degradation (p = 0.02).

CONCLUSION

Chemotherapy and radiation therapy limit acellular dermal matrix remodeling.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

Polypropylene surgical mesh coated with extracellular matrix mitigates the host foreign body response

Surgical mesh devices composed of synthetic materials are commonly used for ventral hernia repair. These materials provide robust mechanical strength and are quickly incorporated into host tissue; factors that contribute to reduced hernia recurrence rates. However, such mesh devices cause a foreign body response with the associated complications of fibrosis and patient discomfort. In contrast, surgical mesh devices composed of naturally occurring extracellular matrix (ECM) are associated with constructive tissue remodeling, but lack the mechanical strength of synthetic materials. A method for applying a porcine dermal ECM hydrogel coating to a polypropylene mesh is described herein with the associated effects upon the host tissue response and biaxial mechanical behavior. Uncoated and ECM coated heavy-weight BARD™ Mesh were compared to the light-weight ULTRAPRO™ and BARD™ Soft Mesh devices in a rat partial thickness abdominal defect overlay model. The ECM coated mesh attenuated the pro-inflammatory response compared to all other devices, with a reduced cell accumulation and fewer foreign body giant cells. The ECM coating degraded by 35 days, and was replaced with loose connective tissue compared to the dense collagenous tissue associated with the uncoated polypropylene mesh device. Biaxial mechanical characterization showed that all of the mesh devices were of similar isotropic stiffness. Upon explanation, the light-weight mesh devices were more compliant than the coated or uncoated heavy-weight devices. This study shows that an ECM coating alters the default host response to a polypropylene mesh, but not the mechanical properties in an acute in vivo abdominal repair model.

Bioprosthetic mesh in abdominal wall reconstruction

Mesh materials have undergone a considerable evolution over the last several decades. There has been enhancement of biomechanical properties, improvement in manufacturing processes, and development of antiadhesive laminate synthetic meshes. The evolution of bioprosthetic mesh materials has markedly changed our indications and methods for complex abdominal wall reconstruction. The authors review the optimal properties of bioprosthetic mesh materials, their evolution over time, and their indications for use. The techniques to optimize outcomes are described using bioprosthetic mesh for complex abdominal wall reconstruction. Bioprosthetic mesh materials clearly have certain advantages over other implantable mesh materials in select indications. Appropriate patient selection and surgical technique are critical to the successful use of bioprosthetic materials for abdominal wall repair.

Thoracic wall reconstruction with Collamend® in trauma: report of a case and review of the literature

INTRODUCTION

Despite progress in reconstructive techniques, rebuilding portions of the thorax remains challenging, in particular when large resections, contamination or infection are involved. No other cases of thoracic reconstruction in trauma patients with biological prosthesis have been described since now.

METHODS

We report a case of thoracic reconstruction in highly infected field in a trauma patient. We also performed a literature review about the topic.

CONCLUSION

Collamend® demonstrated its usefulness in thoracic wall reconstruction even in trauma patients and infected fields.

Stabilization of the chest wall: autologous and alloplastic reconstructions

The goals of chest wall stabilization include maintenance of a rigid airtight cavity, protection of the thoracic and abdominal contents, optimization of respiration, and, whenever possible, an aesthetic reconstruction. Evidence suggests that bony fixation results in reduced ventilator dependence, a shorter overall hospital stay, and improved upper extremity function. We prefer to accomplish this with autologous tissue alone (such as the pectoralis major, latissimus dorsi, or rectus abdominus muscle flaps) for small to moderate defects. En bloc resection of defects larger than 5 cm or containing four or more ribs will likely benefit from chest wall stabilization. For patients previously treated with radiation, even larger defects may be tolerated owing to fibrosis. For these larger defects, methyl methacrylate composite meshes are used and covered with vascularized tissue. Contaminated wounds are generally reconstructed with bioprosthetic mesh rather than synthetic mesh. Using these principles, the reconstructive plastic surgeon can devise a comprehensive and safe plan to repair tremendous defects of the chest wall.

Overview on current and future materials for chest wall reconstruction

This article focuses on new materials available to thoracic surgeons for the reconstruction of chest wall defects. Each surgeon is called to select the best reconstructive strategy based on the disease for which the resection is needed, the possible extension to adjacent structures, the availability of professional colleagues for multidisciplinary involvement, and the preferred (or available) material for full or partial thickness reconstruction.

The use of human acellular dermal matrix for chest wall reconstruction

BACKGROUND

Reconstruction of chest wall defects has evolved, but challenges remain. This is particularly true when defects are large or contamination is present. Although numerous materials are available for reconstruction, acellular dermal matrix has the advantage of becoming vascularized and incorporated autologously. By its resistance to infection and lack of adhesion formation, it is a promising although expensive alternative to synthetic materials in some circumstances. This report examines our experience with human acellular dermal matrix (HADM) in reconstruction of major chest wall and diaphragmatic defects.

METHODS

A retrospective study was conducted of all patients who underwent thoracic reconstruction using HADM between March 2007 and March 2010 at Harbor-University of California-Los Angeles Medical Center. Data acquisition included demographics, surgical indications, operative details, complications, and follow-up evaluation.

RESULTS

Ten patients were identified. Indications included thoracic tumor resection in 5, Clagett procedure modification for postpneumonectomy empyema in 2, resection of chest wall osteomyelitis in 2, and pneumonectomy for multiple aspergillomata in 1. Complications occurred in 4 patients and included respiratory failure, pneumonia, and wound seromas. All wounds healed without need to remove or revise the HADM, and sound chest wall closure was achieved in every case.

CONCLUSIONS

HADM is an effective but expensive alternative to synthetic mesh in reconstruction of chest wall and diaphragmatic defects. It is particularly attractive for use under conditions of potential or overt contamination.

Randomized controlled trial of minimally invasive surgery using acellular dermal matrix for complex anorectal fistula

AIM: To compare the efficacy and safety of acellular dermal matrix (ADM) bioprosthetic material and endorectal advancement flap (ERAF) in treatment of complex anorectal fistula.

METHODS: Ninety consecutive patients with complex anorectal fistulae admitted to Anorectal Surgical Department of First Affiliated Hospital, Xinjiang Medical University from March 2008 to July 2009, were enrolled in this study. Complex anorectal fistula was diagnosed following its clinical, radiographic, or endoscopic diagnostic criteria. Under spinal anesthesia, patients underwent identification and irrigation of the fistula tracts using hydrogen peroxide. ADM was securely sutured at the secondary opening to the primary opening using absorbable suture. Outcomes of ADM and ERAF closure were compared in terms of success rate, fecal incontinence rate, anorectal deformity rate, postoperative pain time, closure time and life quality score. Success was defined as closure of all external openings, absence of drainage without further intervention, and absence of abscess formation. Follow-up examination was performed 2 d, 2, 4, 6, 12 wk, and 5 mo after surgery, respectively.

RESULTS: No patient was lost to follow-up. The overall success rate was 82.22% (37/45) 5.7 mo after surgery. ADM dislodgement occured in 5 patients (11.11%), abscess formation was found in 1 patient, and fistula recurred in 2 patients. Of the 13 patients with recurrent fistula using ERAF, 5 (11.11%) received surgical drainage because of abscess formation. The success rate, postoperative pain time and closure time of ADM were significantly higher than those of ERAF (P < 0.05). However, no difference was observed in fecal incontinence rate and anorectal deformity rate after treatment with ADM and ERAF.

CONCLUSION: Closure of fistula tract opening with ADM is an effective procedure for complex anorectal fistula. ADM should be considered a first line treatment for patients with complex anorectal fistula.

The use of acellular dermal matrix to prevent capsule formation around implants in a primate model

BACKGROUND

Implant-based breast reconstruction is a popular option after mastectomy, but capsular contracture may detract from long-term outcomes. The authors have observed that breast implants covered with acellular dermal matrix (AlloDerm) are less likely to develop a capsule in the area where the implant is in direct contact with the acellular matrix. The authors tested this observation experimentally by comparing capsular formation around implants in the presence and absence of AlloDerm in primates.

METHODS

Eight smooth-surfaced tissue expanders were implanted into eight African green monkeys. In four experimental animals, a sheet of AlloDerm was draped over the tissue expander so as to cover the implant. Four control animals underwent placement of a tissue expander only. Animals were killed after 10 weeks and specimens underwent histologic and immunohistochemical analysis.

RESULTS

Hematoxylin and eosin staining of control specimens revealed the presence of a distinct layer of wavy, parallel arrays of collagen fibers consistent with capsule formation. Immunostaining identified abundant myofibroblasts, a profibrotic cell found in breast capsules. In the AlloDerm-covered specimens, no capsule layer was visible, and specimens stained weakly for myofibroblasts. The difference in myofibroblast staining intensity was statistically significant.

CONCLUSIONS

The use of AlloDerm to partially enclose implants effectively prevented formation of a capsule in areas where AlloDerm contacted the implant at 10 weeks. Long-term studies will be required to determine whether this is a durable result that can be reproduced in humans.

Subtotal thigh flap and bioprosthetic mesh reconstruction for large, composite abdominal wall defects

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.

The use of human acellular dermal matrix for parastomal hernia repair in patients with inflammatory bowel disease: a novel technique to repair fascial defects

PURPOSE

Parastomal hernias occur frequently in patients with inflammatory bowel disease who require a stoma and are associated with high recurrence rates. The tissue weakness at the site of hernia can be overcome by creating neofascia using two separate layers of human acellular dermal matrix.

METHODS

Thirteen consecutive patients with inflammatory bowel disease with symptomatic parastomal hernia underwent open parastomal hernia repair at an academic tertiary referral center whereby the posterior and anterior rectus fascia at the stoma site was reconstructed with human acellular dermal matrix. Patients were followed prospectively for 290 +/- 119 days (mean +/- standard deviation), and data were reviewed for rate of postoperative complications, hernia recurrence, and patient satisfaction.

RESULTS

Mean operative time was 233 +/- 80 (range, 129-355) minutes. No intraoperative complications occurred. Average hospital stay was 8.1 +/- 2.4 (range, 6-14) days. Postoperative complications included seroma formation, incisional separation (2 patients each, 15.4 percent), and superficial wound infection (1 patient, 7.7 percent). There were two cases of asymptomatic hernia recurrence as determined by computerized tomography. These patients did not require any intervention. Overall patient satisfaction with the procedure was high.

CONCLUSIONS

In patients with parastomal hernia, reconstruction of the stoma site and abdominal wall with human acellular dermal matrix seems to be safe and results in high patient satisfaction.

Open pneumothorax resulting from blunt thoracic trauma: a case report

Cases of open pneumothorax have been documented as early as 326 BC. Until the last 50 years, understanding of the epidemiology and treatment of penetrating chest trauma has arisen from military surgery. A better understanding of cardiopulmonary dynamics, advances in ventilatory support, and improvement in surgical technique have drastically improved treatment and increased the survival rate of patients with penetrating thoracic trauma. Open pneumothorax is rare in blunt chest trauma, but can occur when injury results in a substantial loss of the chest wall. This case study presents an adolescent who sustained a large open pneumothorax as a result of being run over by a car. Early and appropriate surgical intervention coupled with coordinated efforts by all members of the trauma team resulted in a positive outcome for this patient.