ASRM Posters Negative Pressure Wound Therapy in Severe Open Fractures: Complications of Coverage Related to Delay in Treatment

Introduction: Loss of a breast free flap is a relatively rare occurrence but is catastrophic and likely multifactorial. This study aims to identify potential risk factors for flap loss and to assess whether different techniques have an impact on salvage. Methods: Retrospective review of all free flaps performed for breast reconstruction at a single institution from 2000-2010. Results: Overall 2138 flaps were performed in 1608 patients (unilateral: 1120 patients, bilateral: 488 patients) with 153 compromised flaps (7.2%) and 43 flap losses (2.0%). Age, BMI, smoking, pre-operative radiation and chemotherapy, timing of reconstruction, and surgeon experience did not affect flap loss. The majority of flap losses occurred following unilateral reconstruction which was significantly higher that bilateral reconstruction (28 vs. 15; p=0.04). Subgroup analysis on flap type demonstrated DIEP and other flaps (SIEA and SGAP) were at significantly higher risk for flap loss (OR 1.43; p=0.02 and 3.61; p=0.05 respectively) compared to TRAM and MS-TRAM flaps. Perforator number did not have an impact on flap loss rates. While an intraoperative complication was not associated with a flap loss, the need for a reoperation was stronger indicative of a flap loss (p<0.0001). Flap salvage was highest within the first 24 hours (83.7%) and significantly less between days 1-3 (38.6%; p<0.0001) and beyond 4 days (29.4%; p<0.0001). Ischemia time was significantly associated with flap loss with a 1% increase in flap loss rate with every minute of ischemia time (p=0.04). An arteriovenous thrombosis was significantly associated with a flap loss than an isolated arterial (n=18) or venous thrombosis (n=14) alone (p=0.009). Salvage techniques (aspirin, heparinzation, thrombectomy, and thrombolytic) had no impact on flap salvage rates. Conclusions: Free flap loss following breast reconstruction is multi-factorial with higher losses in less frequently performed flaps such as an SIEA or gluteal flap and longer ischemia times. Salvage rates are most successful within the first 24 hours, and the use of heparinization, aspirin, and thrombolytics do not improve salvage rates. Long Nerve Defects Repair with Epineural Sheath Conduit-Large Animal Model Maria Madajka, PhD; Can Ozturk, MD; Szopinski Jacek, MD, PhD; Halil Safak Uygur, MD; Grzegorz Kwiecien, MD; Adam Bobkiewicz; Vlodek Siemionow, PhD; Maria Siemionow, MD, PhD, DSc Institution where the work was prepared: Cleveland Clinic, Cleveland, OH, USA Background: Extremity injuries account for several hundred peripheral nerve injuries per year. Nerve gaps that need conduit or allograft material tend to involve regional loss of overlying soft tissues and muscles spanning a gap of over 20 cm. The present standard of care is autograft technique but it requires supportive immunosuppression and demonstrated poor motor recovery. To address these needs we developed a new epineural sheath conduit supported with bone marrow stromal cells (BMSC) to restore 6 cm nerve defects. Epineural sheath is immunologically neutral and contains laminin, enhancing neuronal growth. Addition of BMSC will contribute to structural support and secretion of growth factors for enhancement of nerve regeneration. Methods: Sheep model was used since sheep peripheral nerves are histologically and morphometrically similar to human nerves and long nerve defects can be created. Epineural sheath tube was created from the median nerve by the pull out technique, removing all fascicles. BMSC were obtained from donor animal by flush method, purified by the buffy coat technique and cultured for 14 days. Next, cells were trypsinized, fluorescently labeled and injected into the empty epineural tube in the range of 70-80 x 10 6 cells. Restoration of 6cm median nerve defect with epineural conduit was performed using microsurgical techniques. The following experimental groups (n=6 each) were created: Group 1: Autograft control; Group 2: Autogenic epineural sheath conduit filled with saline; Group 3: Autogenic epineural sheath conduit filled with autogenic BMSC. Group 4: Allogenic epineural sheath conduit filled with autogenic BMSC. At 3 and 6 months follow up, nerve conduction velocity (NCV) and somatosensory evoked potential (SSEP) measurements were taken. Nerve samples were collected for histological analysis. Results: All animals recovered from surgery without complications. The shape and integrity of the conduit was preserved in all groups. NCV and SSEP assessment data confirmed presence of neurosensory responses in both saline and BMSC-filled conduit groups. Immunofluorescent staining of saline and BMSC filled conduit showed the presence of fascicle-like structure in the proximal, middle, and distal parts of the conduit. Smaller diameter fascicles were observed in BMSC filled conduits (Group 3 and 4) in comparison to saline filled conduit (Group 2). Toluidine blue staining showed the presence of myelinated axons in all groups. Conclusions: We confirmed feasibility of using epineural sheath conduit to restore 6 cm nerve defects in sheep model. Immunohistochemical and neurosensory assessment confirmed regenerative properties of the epineural sheath conduit. Characterization of Acute Venous Congestion in a Rat Model using Indocyanine Green Angiography Ahmed E. Nasser, MD; Mitchell S. Fourman, MPhil; Robert P. Gersch, PhD; Hsingli Hsi, BS; Alexander B. Dagum, MD; Mark A. Gelfand, MD; Duc T. Bui, MD Institution where the work was prepared: Stony Brook University Hospital, Stony Brook, NY, USA