Musculoskeletal Transplant Foundation Research Articles

Does Soaking Fresh Frozen Costal Cartilage in an Antibiotic Solution Reduce Postoperative Infection in Rhinoplasty?

Fresh frozen costal cartilage (FFCC), from the Musculoskeletal Transplant Foundation (MTF), has recently gained popularity for use in revision rhinoplasty or primary rhinoplasty when there is a paucity of autologous cartilage. However, there are currently no guidelines related to the use of intraoperative antibiotic soaking to reduce postoperative infection rates when using MTF FFCC. This study aimed to evaluate the efficacy of intraoperative antibiotic soaks in reducing surgical site infection rate when using MTF FFCC grafts in rhinoplasty. A retrospective chart review of patients who underwent rhinoplasty with the use of MTF FFCC in the senior author's practice was conducted between May 2017 and June 2022. The inclusion criteria were rhinoplasty cases using MTF FFCC with minimum of 12 months of follow-up. Fisher exact test was conducted to determine significance in rates of postoperative infection for patients who underwent rhinoplasty with the use of MTF FFCC with (1) intraoperative antibiotic solution soak versus (2) no antibiotic solution soak. A total of 310 patients were included and separated into two cohorts, MTF FFCC intraoperative antibiotic solution soak (n = 200) and no antibiotic solution soak (n = 110). There were a total of four (1.3%) cases of infection, all in the antibiotic soak group. There was no statistically significant difference between the rate of infection in the two cohorts (P = 0.301). Our retrospective cohort study demonstrates that soaking MTF FFCC in an antibiotic solution intraoperatively does not reduce postoperative infection rates in rhinoplasty.

Outcomes of the Use of Fresh-Frozen Costal Cartilage in Rhinoplasty.

Rhinoplasty is made more challenging when there is insufficient septal cartilage for use as graft material. Several autologous and homologous graft options have been used in the past, although each comes with its own set of challenges. Fresh-frozen costal cartilage (FFCC) is an increasingly popular alternative that yields the benefits of homologous tissue while having a lower theoretical risk profile. Given the relatively novel nature of this option, the authors analyzed the complication rates of Musculoskeletal Transplant Foundation FFCC. A retrospective chart review of the use of FFCC in rhinoplasty in the senior author's (R.G.R.) practice was conducted between March of 2018 to December of 2021. A total of 282 cases were reviewed and analyzed for rates of infection, warping, and resorption. Patients with a minimum of 12 months of follow-up were included. The mean age of the study group was 35.8 years, and 27 male and 255 female patients were included. Forty cases were primary rhinoplasties; the remaining 242 were revisions. The mean follow-up period was 20.3 months. Six patients (2.1%) required empiric antibiotics postoperatively; no patient had clinical signs of warping, resorption, or displacement, and 6 patients (2.1%) required operative revision unrelated to the FFCC. This study provides follow-up data on the complication profile of FFCC in rhinoplasty. Acute infection, warping, and resorption rates were found to be no greater than rhinoplasty complication rates when autologous or homologous tissue is used. FFCC is a safe, convenient, and patient-centered option for graft tissue in rhinoplasty. Therapeutic, IV.

A Cohort Analysis of Early Outcomes After AlloDerm, FlexHD, and SurgiMend Use in Two-Stage Prepectoral Breast Reconstruction.

Acellular dermal matrix (ADM) is frequently utilized in prepectoral breast reconstruction, but few studies have examined the role of ADM type in complication risk. This study was performed to determine the impact of ADM type on early complication rates in 2-stage alloplastic prepectoral breast reconstruction. We performed a cohort examination of all patients who underwent mastectomy with immediate 2-stage alloplastic prepectoral breast reconstruction with ADM support at Memorial Sloan Kettering Cancer Center from 2018 to 2021. ADM types utilized included AlloDerm (LifeCell Corporation, Branchburg, NJ), FlexHD (MTF Biologics, Edison, NJ), and SurgiMend (Integra LifeSciences Corporation, Princeton, NJ). Complication rates based on the number of tissue expanders (TEs) were determined for each ADM type. Performance of multivariate logistic regression determined the impact of ADM type on complication risk after accounting for confounders. Overall, 726 patients (1054 TEs: 194 AlloDerm, 93 FlexHD, 767 SurgiMend) were included. The 3 cohorts differed in terms of mastectomy type (nipple-sparing: 23.5% of AlloDerm, 33.3% of FlexHD, 19.1% of SurgiMend, P = .038); ADM perforation (perforated: 94.8% of AlloDerm, 98.2% of FlexHD, 100% of SurgiMend, P < .001); and ADM size (AlloDerm: 153.2 cm2 [37.6], SurgiMend: 198.7 cm2 [10.4], FlexHD: 223.7 cm2 [37.9], P < .001). On univariate examination, no differences existed between ADM types for seroma, infection, exposure, malposition, or TE loss. Additionally, after adjustment for confounders with multivariate regression, no ADM type had higher odds of TE loss. In this large cohort of prepectoral reconstruction patients, ADM type did not significantly affect the risk of complications. Additional prospective studies are warranted to better evaluate ADM choice for prepectoral breast reconstruction.

29-LB: Multicenter, Randomized Controlled Clinical Investigation Evaluating a Unique Micro Water Jet Technology Device vs. Standard Debridement in the Treatment of Diabetic Foot Wounds

Background: Proper debridement of the wound base is critical to facilitate wound granulation and closure in non-healing diabetic foot ulcers(DFUs). A unique micro water jet device has been developed and recently granted breakthrough designation for treatment of DFUs by the Foot and Drug Administration(FDA) that precisely cleans acute and chronic wounds in a tissue-preserving manner while performing a precise mechanical cleaning and stimulation of the wound base to enhance granulation and healing. Methods: 170 patients were screened, and 96 patients were enrolled for the analysis, in a two arm randomized controlled trial. DFUs that were non-healing for at least 4 weeks, with adequate blood flow and were void of clinical infection or osteomyelitis were entered into 2 weeks of screening. Those that met all the qualifications were randomized to receive either weekly micro jet wound debridement or standard sharp debridement along with SOC wound dressing and offloading. Both groups were followed for 16 weeks. The primary study endpoint was healing at 16 weeks and the secondary endpoints included a safety analysis. Results: At 16 weeks 65%(28/43) of the Micro Water jet treated DFUs healed compared with 42%(22/53) treated with standard sharp debridement p=0.021 (unadjusted). Further, at 16 weeks, the safety analysis showed with regard to wound related adverse events (AE) and serious adverse events (SAE); 4 AEs and 1 SAE occurring in the Micro Water jet group versus 12 AEs and 4 SAEs in the standard sharp debridement group. Conclusion: The micro water jet device was able to statistically significantly close more refractory DFUs over 16 weeks, without the need for any advanced biologic or graft. Further, the number of wound related infections and hospitalizations were 75% less in those patients treated in the Micro Water jet group. Further evaluation is warranted to validate these initial promising findings. Disclosure D. G. Armstrong: Research Support; Medaxis LLC. R. Galiano: Advisory Panel; Medaxis LLC, Research Support; 3M/KCI, Speaker's Bureau; Musculoskeletal Transplant Foundation. M. J. Carter: Research Support; Medaxis LLC. C. M. Zelen: Research Support; Medaxis LLC.

Osseointegration and Remodeling of Mineralized Bone Graft Are Negatively Impacted by Prior Treatment with Bisphosphonates.

Bisphosphonates limit resorption by inhibiting osteoclast formation and activation. They are removed during preparation of demineralized bone matrix (DBM) particles, but it is not known if osteogenesis and incorporation of mineralized bone allografts from patients treated with oral bisphosphonates are affected in vivo. Human block allografts from 3 bisphosphonate-treated donors and 3 age and sex-matched control donors who had not received bisphosphonates were obtained (Musculoskeletal Transplant Foundation); one-half from each donor was demineralized. In the first study, 3 × 2-mm mineralized and demineralized cylindrical grafts were implanted bilaterally in the femoral metaphysis of 56 rats. In the second study, samples from each group were pooled, prepared as particles, and implanted bilaterally in the femoral marrow canal of 24 rats. Osseointegration, defined as native bone in contact with allograft, was assessed at 10 weeks by micro-computed tomography (CT) and histomorphometry. Micro-CT showed greater bone volume in sites treated with demineralized samples compared with the control mineralized and bisphosphonate-exposed mineralized samples. More new bone was generated along the cortical-endosteal interface compared with mineralized samples. Histology showed significantly less new bone in contact with the mineralized bisphosphonate-exposed allograft (10.4%) compared with mineralized samples that did not receive bisphosphonates (22.8%) and demineralized samples (31.7% and 42.8%). A gap was observed between native bone and allograft in the bisphosphonate-exposed mineralized samples (0.50 mm 2 ). The gap area was significantly greater compared with mineralized samples that did not receive bisphosphonates (0.16 mm 2 ) and demineralized samples (0.10 and 0.03 mm 2 ). Mineralized allografts were osseointegrated, but not remodeled or replaced by living bone, preventing full regeneration of the bone defect. Prior treatment of the donor with bisphosphonates affected osteogenesis, preventing osteointegration and remodeling of the allograft into the regenerating bone. Clinical use of mineralized allografts from patients who had received bisphosphonate therapy needs to be evaluated; in this animal model, such grafts were not integrated into the host bone or remodeled, and full regeneration of the bone defects was prevented.

30-LB: Multicenter, Randomized Controlled Clinical Investigation Evaluating a Unique Micro Water Jet Technology Device Versus Standard Debridement in the Treatment of Diabetic Foot

Background: Proper debridement of the wound base is critical to facilitate wound granulation and closure in non-healing diabetic foot ulcers (DFUs) . A unique micro water jet device has been developed that precisely cleans acute and chronic wounds in a tissue-preserving manner while performing a precise mechanical cleaning and stimulation of the wound base to enhance granulation and healing. In this trial the device was used to treat non healing DFUs. Methods: 85 patients were screened, and 50 patients were enrolled for the preliminary analysis, in a two arm randomized controlled trial. Diabetic foot wounds that were non-healing for at least 4 weeks, with adequate blood flow and were void of clinical infection or osteomyelitis were entered into 2 weeks of screening. Those that met all the qualifications were randomized to receive either weekly micro jet wound debridement or standard sharp debridement along with SOC wound dressing and offloading. Both groups were followed for 16 weeks. The study endpoints included healing at 16 weeks as well as percent area wound reduction (PAR) over the treatment phase of 16 weeks. Results: At 16 weeks 72% (18/25) of the Micro Water jet treated DFUs healed compared with 40% (10/25) treated with standard sharp debridement p=0.023 (unadjusted) . Furthermore, at 16 weeks, the percent area reduction (PAR) was 86.5% (SD: 25.60) for the wounds treated with the Micro Water Jet versus 35.1% (SD: 164.47) with standard sharp wound debridement p=0.021 (unadjusted) . The safety analysis showed with regard to wound related adverse events (AE) and serious adverse events (SAE) ; 1 AE and 1 SAE occurring in the Micro Water jet group versus 9 AEs and 4 SAEs in the standard sharp debridement group. Conclusion: The micro water jet device was able to statistically significantly close more refractory DFUs over 16 weeks, with a significant difference in wound area reduction that should be noted. Further evaluation with larger randomized controlled trials are warranted to validate these initial promising findings. Disclosure D. G. Armstrong: None. C. Zelen: Research Support; Geistlich Pharma, Medaxis LLC, Musculoskeletal Transplant Foundation, PolarityTE, Inc. Funding Medaxis LLC (A0010)

CORR Insights®: Substantial Inconsistency and Variability Exists Among Minimum Clinically Important Differences for Shoulder Arthroplasty Outcomes: A Systematic Review.

1Professor and Chairman, New York University School of Medicine, Orthopaedic Surgery, Surgeon-in-Chief, NYU Langone Orthopedic Hospital, New York, NY, USA J. D. Zuckerman ✉, New York University School of Medicine, Orthopaedic Surgery, Hospital for Joint Diseases, 301 East 17th Street, 14th Floor, New York, NY 10003, USA, Email: [email protected] This CORR Insights® is a commentary on the article “Substantial Inconsistency and Variability Exists Among Minimum Clinically Important Differences for Shoulder Arthroplasty Outcomes: A Systematic Review” by Kolin and colleagues available at: DOI: 10.1097/CORR.0000000000002164. The author certifies receipt of personal payments of benefits, during the study period, in the amount of USD 10,000 to USD 1,000,000 from Exactech Inc, and in the amount of USD 10,000 to USD 100,000 from the Musculoskeletal Transplant Foundation. All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research® editors and board members are on file with the publication and can be viewed on request. The opinions expressed are those of the writer, and do not reflect the opinion or policy of CORR® or The Association of Bone and Joint Surgeons®.

372. Detection of SARS-CoV-2 RNAemia in Deceased Tissue Donors

BackgroundTissue donors are evaluated for communicable disease in order to minimize the risk of transmission to recipients. Although there are data suggesting SARS-CoV-2 viremia across a wide spectrum of illness, prevalence in deceased tissue donors and the potential for transplant transmission are unknown.MethodsEight tissue banks participated in a retrospective analysis of samples from eligible deceased tissue donors from Oct 2019 through June 2020, one participant in Canada and the remainder located in the United States. All four Census regions of the continental US and all major racial-ethnic groups were represented. EDTA or sodium citrate plasma aliquots were tested in singlicate with the Research Use Only Procleix SARS-CoV-2 Assay on the Procleix Panther System, which uses transcription-mediated nucleic acid amplification (TMA) technology for detection of the SARS-CoV-2 RNA. Plasma (or if unavailable, serum) aliquots were sent to Grifols for an alternate SARS-CoV-2 nucleic acid amplification (NAT) test to verify reactivity and also sent for antibody testing using the emergency use authorization Ortho VITROS Immunodiagnostic Products Anti-SARS-CoV-2 Total test. The VITROS assay uses immunometric technology for qualitative measurement of total antibody (IgG, IgA and IgM) to SARS-CoV-2. The proportion of donors with confirmed RNAemia (i.e., presence of SARS-CoV-2 RNA in plasma or serum) and 95% confidence intervals were computed.ResultsOf 3,455 donor samples with valid final results, 26 (0.76%) were initially positive for SARS-CoV-2 RNA; of these, 3 were confirmed by alternate NAT. Of donor samples collected in 2019 0.00% (95% CI: 0.00%,0.43%) were confirmed RNAemic, while of those collected in 2020, 0.12% (0.04%,0.34%) were confirmed RNAemic. One of 26 initial positive, and none of the three samples confirmed by alternate NAT, tested positive for anti-SARS-CoV-2 Spike antibodies by serology. Infectivity studies are pending on one sample with sufficient available volume.ConclusionThe rate of SARS-CoV-2 RNAemia in deceased tissue donors is approximately 1 per 1,000, and it is unknown whether this RNAemia reflects the presence of infectious virus. Given these results, the risk of transmission through tissue is most likely to be low.Disclosures Melissa Greenwald, MD, Alamo Biologics (Consultant)Eurofins VRL Laboratories (Consultant)Right Cell Biologics (Consultant, Consultant Medical Director) Eduard Grebe, PhD, Gilead Sciences (Consultant)Sedia Biosciences Corporation (Consultant, Grant/Research Support)Vitalant (Employee) Alyce Linthurst Jones, PhD, LifeNet Health (Employee) Matthew Kuehnert, MD, American Association of Tissue Banks (Board Member)ICCBBA (Board Member)Musculoskeletal Transplant Foundation (Employee)

926. COVID-19 Infections After SARS-CoV-2 Vaccination in Solid Organ Transplant Recipients

BackgroundSolid organ transplant recipients (SOTR) have lower humoral responses following SARS-CoV-2 vaccination. Whether this equates to reduced vaccine effectiveness in SOTR or impacts disease severity is not yet known. We used the IDSA Emerging Infections Network (EIN) to identify SARS-CoV-2 cases in vaccinated SOTR. We describe their clinical characteristics and outcomes.MethodsOn 4/7/21, we requested case reports via the EIN listserv of COVID-19 infection following SARS-CoV-2 vaccination in immunocompromised individuals. Case reports were collected until June 7th. Online data collection included patient demographics, dates of SARS-CoV-2 vaccine administration and clinical data related to COVID-19 infection. We performed a descriptive analysis of these patient factors and compared differences between early onset (< / = 21 days after completing vaccine series) and late onset infection ( > 21 days after completing vaccine series).ResultsAs of 6/7/21, 34 cases of COVID-19 infection after vaccination in SOTR were submitted. Most cases (79%) occurred in individuals who were fully vaccinated. Only 3 cases (8.5%) occurred in SOTR within their first year after transplantation. Clinical characteristics are listed in Table 1. The vaccine administration date was known for 26 SOTR among whom symptoms occurred a median of 26.5 days (IQR 21.75 days, range 5-79 days) after completing the COVID-19 vaccine series. Twenty-three SOTR (68%) required hospitalization of which 12 had critical illness. Outcome data was available for 29 individuals of whom 20 (69%) demonstrated improvement. When comparing SOTR with early versus late onset COVID-19 infection in relation to vaccination timing, there were no differences in disease severity (80% vs 75% with severe or critical disease, p=NS) or outcome (30% vs 31% died or deteriorating, p=NS).Table 1: Characteristics of Solid Organ Transplant Recipients with COVID-19 Infection Following SARS-CoV-2 Vaccination ConclusionSARS-CoV-2 infections after vaccination are occurring in SOTR, including cases of critical illness, suggesting reduced vaccine effectiveness within this vulnerable population. We did not appreciate any correlation between time from vaccination and COVID-19 disease severity or outcome. Further studies evaluating the true incidence of and risk factors for breakthrough infections among vaccinated SOTR are needed.Disclosures Matthew Kuehnert, M.D., American Association of Tissue Banks (Board Member)ICCBBA (Board Member)Musculoskeletal Transplant Foundation (Employee) John W. Baddley, M.D., Eli Lilly (Consultant)Pfizer (Consultant)R-Pharm (Consultant)Viela Bio (Consultant)

MP29-17 A DECELLULARIZED SKELETAL MUSCLE-DERIVED ECM FOR IN SITU MUSCLE REGENERATION

INTRODUCTION AND OBJECTIVE: Cell-based tissue engineering strategies have gained attention in restoring normal tissue function for reconstructive procedures; however, these approaches require a donor tissue biopsy and extensive cell expansion process prior to implantation. In order to avoid this limitation, we developed a cell-free muscle-specific scaffolding system that consists of a skeletal muscle-derived decellularized extracellular matrix (dECM) and a myogenic factor, insulin growth factor-1 (IGF-1). We hypothesized that muscle-derived dECM biomaterials combined with IGF-1 could provide a muscle-specific microenvironment for in situ muscle tissue regeneration. We developed a novel dECM-based scaffolding system containing IGF-1 and characterized its rheological properties and in vitro biological properties for tissue reconstruction. METHODS: We developed a novel dECM-based scaffolding system containing IGF-1 and characterized its rheological properties and in vitro biological properties. In addition, we investigated the feasibility of using this dECM-based scaffolding system for in situ muscle tissue regeneration in a rabbit TA muscle defect model. RESULTS: The cell viability in all scaffolds had over 90% at 1, 3, and 7 days in culture. The cell proliferation in the IGF-1/dECM was significantly increased when compared with other groups. More importantly, the IGF-1/dECM strongly supported the myogenic differentiation in the scaffold as confirmed by MHC immunofluorescence. We also investigated the feasibility in a rabbit tibialis anterior (TA) muscle defect model. The IGF-1/dECM had a significantly greater number of myofibers when compared to both collagen and dECM groups at 1 and 2 months after implantation. CONCLUSIONS: We developed the muscle-specific dECM-based scaffolding system and investigated the synergistic effect of the dECM with IGF-1 for in situ muscle regeneration. The dECM was obtained by the decellularization of skeletal muscle tissue, followed by the solubilization. Combining with IGF-1, the dECM showed high in vitro cellular activities, including cell viability, proliferation, and differentiation. Moreover, in vivo implantation of IGF-1/dECM scaffold in the rabbit TA muscle defect model showed an acceleration in the new muscle formation. We demonstrated that this novel muscle-specific scaffolding system could enhance the body’s regenerative capability for the in situ muscle tissue regeneration, which may have potential utility in reconstruction. Source of Funding: This study was supported by the Musculoskeletal Transplant Foundation (MTF).

Raman Biomarkers Are Associated with Cyclic Fatigue Life of Human Allograft Cortical Bone.

Structural bone allografts are an established treatment method for long-bone structural defects resulting from such conditions as traumatic injury and sarcoma. The functional lifetime of structural allografts depends on resistance to cyclic loading (cyclic fatigue life), which can lead to fracture at stress levels well below the yield strength. Raman spectroscopy biomarkers can be used to non-destructively assess the 3 primary components of bone (collagen, mineral, and water), and may aid in optimizing allograft selection to decrease fatigue fracture risk. We studied the association of Raman biomarkers with the cyclic fatigue life of human allograft cortical bone. Twenty-one cortical bone specimens were machined from the femoral diaphyses of 4 human donors (a 63-year old man, a 61-year-old man, a 51-year-old woman, and a 48-year-old woman) obtained from the Musculoskeletal Transplant Foundation. Six Raman biomarkers were analyzed: collagen disorganization, mineral maturation, matrix mineralization, and 3 water compartments. The specimens underwent cyclic fatigue testing under fully reversed conditions (35 and 45 MPa), during which they were tested to fracture or to 30 million cycles ("runout"), simulating 15 years of moderate activity. A tobit censored linear regression model for cyclic fatigue life was created. The multivariate model explained 60% of the variance in the cyclic fatigue life (R = 0.604, p < 0.001). Increases in Raman biomarkers for disordered collagen (coefficient: -2.74×10, p < 0.001) and for loosely collagen-bound water compartments (coefficient: -2.11×10, p < 0.001) were associated with a decreased cyclic fatigue life. Increases in Raman biomarkers for mineral maturation (coefficient: 3.50×10, p < 0.001), matrix mineralization (coefficient: 2.32×10, p < 0.001), tightly collagen-bound water (coefficient: 1.19×10, p < 0.001), and mineral-bound water (coefficient: 3.27×10, p < 0.001) were associated with an increased cyclic fatigue life. Collagen disorder accounted for 44% of the variance in the cyclic fatigue life, mineral maturation accounted for 6%, and all bound water compartments accounted for 3%. Increasing baseline collagen disorder was associated with a decreased cyclic fatigue life and had the strongest correlation with the cyclic fatigue life of human cortical donor bone. This model should be prospectively validated. Raman analysis is a promising tool for the non-destructive evaluation of structural bone allograft quality for load-bearing applications.

Chemical sterilization of allograft dermal tissues.

Common terminal sterilization methods are known to alter the natural structure and properties of soft tissues. One approach to providing safe grafts with preserved biological properties is the combination of a validated chemical sterilization process followed by an aseptic packaging process. This combination of processes is an accepted method for production of sterile healthcare products as described in ANSI/AAMI ST67:2011. This article describes the validation of the peracetic acid and ethanol-based (PAAE) chemical sterilization process for allograft dermal tissues at the Musculoskeletal Transplant Foundation (MTF, Edison, NJ). The sterilization capability of the PAAE solution used during routine production of aseptically processed dermal tissue forms was determined based on requirements of relevant ISO standards, ISO 14161:2009 and ISO 14937:2009. The resistance of spores of Bacillus subtilis, Clostridium sporogenes, Mycobacterium terrae, Pseudomonas aeruginosa, Enterococcus faecium, and Staphylococcus aureus to the chemical sterilization process employed by MTF was determined. Using a worst-case scenario testing strategy, the D value was calculated for the most resistant microorganism, Bacillus. The 12D time parameter determined the minimum time required to achieve a SAL of 10-6. Microbiological performance qualification demonstrated a complete kill of 106 spores at just a quarter of the full cycle time. The validation demonstrated that the PAAE sterilization process is robust, achieves sterilization of allograft dermal tissue to a SAL 10-6, and that in combination with aseptic processing secures the microbiological safety of allograft dermal tissue while avoiding structural and biochemical tissue damage previously observed with other sterilization methods such as ionizing irradiation.

Aseptically Processed Placental Membrane Improves Healing of Diabetic Foot Ulcerations: Prospective, Randomized Clinical Trial.

Background:Allogeneic grafts derived from amnion/chorion are known to be efficacious in healing chronic diabetic foot ulcerations (DFUs). The goal of this study was to compare aseptically processed dehydrated human amnion and chorion allograft (dHACA) versus standard of care (SOC) in facilitating wound closure in nonhealing DFUs.Methods:Patients with DFUs treated with SOC (off-loading, appropriate debridement, and moist wound care) after a 2-week screening period were randomized to either SOC or wound-size-specific dHACA (AmnioBand, Musculoskeletal Transplant Foundation, Edison, N.J.) applied weekly for up to 12 weeks plus SOC. Primary endpoint was the percentage of wounds healed at 6 weeks between groups.Results:At 6 weeks, 70% (14/20) of the dHACA-treated DFUs healed compared with 15% (3/20) treated with SOC alone. Furthermore, at 12 weeks, 85% (17/20) of the DFUs in the dHACA group healed compared with 25% (5/20) in the SOC group, with a corresponding mean time to heal of 36 and 70 days, respectively. At 12 weeks, the mean number of grafts used per healed wound for the dHACA group was 3.8 (median 3.0), and mean cost of the tissue to heal a DFU was $1400. The mean wastage at 12 weeks was 40%. One adverse event and 1 serious adverse event occurred in the dHACA group; neither was graft related. Three adverse events and 1 serious adverse event occurred in the SOC group.Conclusion:Aseptically processed dHACA heals diabetic foot wounds significantly faster than SOC at 6 and 12 weeks with minimal graft wastage.

A Novel Reticular Dermal Graft Leverages Architectural and Biological Properties to Support Wound Repair.

Acellular dermal matrices (ADMs) are frequently used in reconstructive surgery and as scaffolds to treat chronic wounds. The 3-dimensional architecture and extracellular matrix provide structural and signaling cues for repair and remodeling. However, most ADMs are not uniformly porous, which can lead to heterogeneous host engraftment. In this study, we hypothesized that a novel human reticular ADM (HR-ADM; AlloPatch Pliable, Musculoskeletal Transplant Foundation, Edison, N.J.) when aseptically processed would have a more open uniform structure with retention of biological components known to facilitate wound healing. The reticular and papillary layers were compared through histology and scanning electron microscopy. Biomechanical properties were assessed through tensile testing. The impact of aseptic processing was evaluated by comparing unprocessed with processed reticular grafts. In vitro cell culture on fibroblasts and endothelial cells were performed to showcase functional cell activities on HR-ADMs. Aseptically processed HR-ADMs have an open, interconnected uniform scaffold with preserved collagens, elastin, glycosaminoglycans, and hyaluronic acid. HR-ADMs had significantly lower ultimate tensile strength and Young's modulus versus the papillary layer, with a higher percentage elongation at break, providing graft flexibility. These preserved biological components facilitated fibroblast and endothelial cell attachment, cell infiltration, and new matrix synthesis (collagen IV, fibronectin, von Willebrand factor), which support granulation and angiogenic activities. The novel HR-ADMs provide an open, interconnected scaffold with native dermal mechanical and biological properties. Furthermore, aseptic processing retains key extracellular matrix elements in an organized framework and supports functional activities of fibroblasts and endothelial cells.

The effect of sulfation in glycosaminoglycan (GAG)-mimetic scaffolds on promoting chondrogenesis

Event Abstract Back to Event The effect of sulfation in glycosaminoglycan (GAG)-mimetic scaffolds on promoting chondrogenesis Gloria Portocarrero Huang1, Roseline Menezes1, Richard Vincent1, Willis Hammond1, George Collins1 and Treena Livingston Arinzeh1 1 New Jersey Institute of Technology, Department of Biomedical Engineering, United States Introduction: Articular cartilage has a limited ability to heal. Current surgical procedures to repair cartilage result in the formation of fibrocartilage instead of hyaline cartilage. The presence of fibrocartilage may suggest deficient bioactivity to promote the chondrocyte phenotype. Glycosaminoglycans (GAGs) have been shown to interact and maintain the bioactivity of growth factors due to their level and spatial distribution of sulfate groups[1]. Cellulose sulfate, a semi-synthetic derivative of cellulose, is a sulfated polysaccharide with structural similarity to GAGs and has yet to be explored for cartilage repair. It is a cost-effective alternative to the use of naturally occurring GAGs for cartilage repair applications. This study evaluated the effect of varying the degree of sulfation in cellulose sulfate on human mesenchymal stem cell (MSC) chondrogenesis and its effect on maintaining the bioactivity of transforming growth factor-β3 (TGF-β3), a potent driver of chondrogenesis, in comparison to other sulfated GAGs. Materials and Methods: Cellulose sulfate was combined with bovine gelatin, electrospun to form fibrous scaffolds and characterized for fiber dimension, interfiber spacing, and interactions with TGF-β3. Interactions with TGF-β3 were additionally evaluated in solutions of cellulose sulfate. Partially sulfated cellulose (pSC) and fully sulfated cellulose (NaCS) were evaluated at 0.1% and 5% dry weight of the scaffold. Gelatin (Gel) with no cellulose sulfate was used as a control. MSCs were seeded onto the scaffold and chondrogenesis was evaluated after 56 days through the production of collagen type 2, cell morphology, and gene expression of chondrogenic markers. Results and Discussion: NaCS had significantly higher amounts of complexed TGF-β3 than chondroitin 6-sulfate (CSC) and pSC in solution (Figure 1A) and increasing the cellulose sulfate on the scaffold bound more TGF-β3 (Figure 1B). Yet, MSCs on pSC-gel scaffolds had the highest production of collagen type II (Figure 2A & 2B) and greatest gene expression for chondrocyte markers (aggrecan, collagen type II, chondroadherin, and Sox9). On scaffolds with cellulose sulfate, cells had a lower production of collagen type I per cell, a protein found in fibrocartilage, compared to gelatin alone (Figure 3). The cells on the scaffolds had lower gene expression of collagens type X and I as indicators of hypertrophic chondrocytes and MSCs, respectively, when compared to cells in MSC chondrogenic control cultures. Conclusion: The findings suggest that pSC-gel scaffolds, having partial sulfation, may support a more homogeneous cartilage tissue formation. Future studies will understand the interactions of the growth factors and GAGs to improve scaffold design and further promote tissue formation. National Science Foundation; Musculoskeletal Transplant Foundation

Inverse gradient matrix system for osteochondral tissue engineering

Event Abstract Back to Event Inverse gradient matrix system for osteochondral tissue engineering Deborah Dorcemus1, 2, 3, Eve George2, 4 and Syam Nukavarapu1, 2, 3, 5 1 University of Connecticut, Biomedical Enigneering, United States 2 University of Connecticut Health Center, Institute for Regenerative Engineering, United States 3 University of Connecticut Health Center, Orthopaedic Surgery, United States 4 Georgia Institute of Technology, Biomedical Enigneering, United States 5 University of Connecticut, Materials Science and Engineering, United States Introduction: Osteoarthritis (OA) is a growing issue worldwide, yet many of the clinical treatments for OA are only palliative[1]. Since osteochondral (OC) defect repair remains a significant problem in orthopedic surgery, researchers are currently working to develop matrix systems for OC repair and regeneration[2]. While some success was reached using single and bi-phasic designs, overtime, the need for more tailored systems became apparent[3]-[5]. Our group has introduced a graded structure with bone and cartilage supporting layers arranged in reverse gradients in order to achieve an integrated OC matrix system. We hypothesize that by carefully tailoring each biomaterial phase we can not only support regeneration of the bone phase, but also provide the cues necessary to promote regeneration of the cartilage phase. Here, we aim to design and investigate the hydrogel phase with varying mechanical strength to support cartilage regeneration, and explore the gel’s integration into the polymeric phase creating a new generation scaffold system for OC defect repair and regeneration. Materials and Methods: Using the Hystem kit (ESIŸ BIO), a hyaluaronan gel (HA) was mixed with a polyethylene glycol (PEG) cross-linker in ratios of 1:1 – 1:7 (PEG:HA), and characterized for storage/loss modulus using a rheometer. After a range of gels were selected based on their mechanical profiles (1:2, 1:4, and 1:7), 400-500k mesenchymal stem cells were seeded in the gels and cultured for 21 days in chondrogenic media. After 21 days the GAG content of the samples were determined through alcian blue staining as well as the DMMB assay. Additionally, immunofluorescence (IF) staining was done to observe collagen II, aggrecan, and Sox9. Finally, using thermal sintering and porogen leaching, poly(85 lactide-co-15 glyclolide) (PLGA) microspheres were fabricated into a gradient scaffold which was infiltrated with the selected gel prior to μCT analysis[6]. Results and Discussion: Based on the rheological data it was determined that modification of the PEG:HA ratio can vary the overall modulus of the gels (~10Pa -45Pa). After 21 days of culture the results show that with an increase in modulus there is also an increase in GAG expression and presence of key proteins such as collagen II and aggrecan (Figure 1). The time sensitive crosslinking of the HA gel allows it to infiltrate the available pore space of the gradient matrix prior to full gelation, acting as a chondro-inductive secondary phase/cell delivery vehicle. This said, as supported by the μCT data, when the designed gel is used to infiltrate the pore space of the matrix we find that there is in fact an inverse gradient of hydrogel to polymer (Figure 2). Conclusions: The complexity of OC tissue regeneration lies in the need to not only regenerate cartilage and bone but also the interface region. Based on the quantitative and qualitative expression data, we established a gel matrix suitable for regeneration of the cartilage phase of OC tissue by studying the effects of mechanical strength on cartilage regeneration. With the identified cartilage phase incorporated into the graded PLGA structure we have now designed an inverse gradient matrix system capable of supporting fully integrated OC tissue regeneration. AO Foundation (S-13-122N); National Science Foundation (1311907); Musculoskeletal Transplant Foundation (MTF); Connecticut Institute for Clinical and Translational Sciences (CICATS)

Comparison Study of Acellular Dermal Matrices in Complicated Hernia Surgery

Damage control surgery and management of the open abdomen has led to a significant improvement in survival in trauma and emergency surgical patients. However, subsequent abdominal reconstruction has become a significant challenge. The objective of this study was to compare 2 different acellular dermal matrices in regard to hernia recurrence and complications in patients who present with a large complicated ventral hernia as a result of trauma or emergency surgery. A prospective quasi-experimental time-interrupted series design was used to evaluate the incidence of hernia recurrence in trauma/emergency surgery patients who had a ventral hernia repair with a biologic matrix. From January 2005 to December 2007, 55 patients with a complicated ventral hernia were repaired with AlloDerm (Life Cell Corporation). Beginning in February 2008 to January 2010, 40 patients with the same criteria were repaired with FlexHD (Musculoskeletal Transplant Foundation) and followed prospectively over the following year. The primary outcome for this study was hernia recurrence (functional or real) at 1 year. Other outcomes variables included abdominal laxity, seroma formation, and wound or intra-abdominal infection. There was no significant difference in age, sex, and body mass index between the groups. In addition, there was no significant difference in the mean hernia size and size of the acellular dermis that was inserted. At 1 year postsurgery, all of the AlloDerm patients were diagnosed with recurrence requiring a second formal repair. Eleven patients (31%) whose hernias were repaired with FlexHD were diagnosed with a recurrence requiring a second formal repair. FlexHD appears to have reduced the recurrence and laxity rates while maintaining a similar complication profile compared with AlloDerm in trauma/emergency surgery patients with large complicated ventral hernias.

Resistance of Acellular Dermal Matrix Materials to Microbial Penetration

Acellular dermal matrices have many current and potential applications, but their long-term safety has not been extensively studied. In particular, limited information exists regarding such materials' resistance to infection. To assess the resistance to microbial penetration of common acellular dermal matrix materials used in reconstruction after skin cancer excision, treatment of chronic ulcers and burns, breast reconstruction, hernia repairs, and other applications. Comparative in vitro study of 4 commercially available dermal substitutes for their ability to act as barriers to penetration by common skin pathogens. University-based dermatology and plastic surgery departments and a hospital microbiology laboratory. Four commercially available dermal substitutes, including AlloDerm (LifeCell), FlexHD (Musculoskeletal Transplant Foundation), Strattice (LifeCell), and NeoForm (Mentor Corporation). We tested the 4 dermal matrix materials with the following 4 organisms commonly implicated in wound infections: Staphylococcus aureus, Pseudomonas aeruginosa, Streptococcus pyogenes, and Candida albicans. Each material was inoculated with the same concentration of each pathogen. The number of bacterial colonies grown on blood agar plates. AlloDerm and rehydrated FlexHD were found to be the best barriers to penetration by P. aeruginosa. AlloDerm, FlexHD, and Strattice also prevented penetration by S. aureus and S. pyogenes; NeoForm was less effective in withstanding these organisms. The results of this study were inconclusive with regard to C. albicans penetration. Three of the 4 commonly used acellular dermal matrix materials are resistant to in vitro penetration by S. aureus and S. pyogenes and partially resistant to P. aeruginosa. Resistance to fungal pathogens is uncertain. Antimicrobial differences across matrix materials may influence their selection for particular uses, such as treatment of refractory leg ulcers or reconstruction after skin cancer excision.

Postraumatic frontal sinus obliteration with calvarial bone dust and demineralized bone matrix: a long term prospective study and literature review

Defining the ideal material for frontal sinus obliteration remains controversial. Autogenous cancellous bone is effective because of its biological properties: it undergoes fast revascularization acting as an active scaffold for bone healing, but is linked to additional donor site morbidity. Bone dust harvesting from the skull surface produces no sequelae but availability is limited. Many efforts have been made to overcome these drawbacks, and an ideal bone substitute sought. Demineralized Bone Matrix (DBX; Musculoskeletal Transplant Foundation, Edison, NJ, USA) is a commercially available product composed of demineralized bone particles reduced after proper processing of human bone in combination with sodium hyaluronate. It generates an osteoconductive surface and it is also a source of osteoinductive factors. Radiological follow-up using computed tomography is a very reliable method of following-up ossification and detecting the early signs of possible complications. The authors present their clinical series of postraumatic frontal sinus obliteration using a mixture of calvarial bone dust and DBX shell, with long-term radiological monitoring. The technique was demonstrated to be effective, reliable, stable in the long term and associated with minimal morbidity.

Discussion

Grand Rapids, Mich. From Partners in Plastic Surgery. Received for publication May 21, 2012; accepted May 22, 2012. Disclosure:Dr. Hammond has a consulting agreement with the Musculoskeletal Transplant Foundation. Dennis C. Hammond, M.D.; 4070 Lake Drive SE, Suite 202, Grand Rapids, Mich. 49546, [email protected]