Michelle Seu

Abstract 10.55 BRIDGING THE GAP: EXTENDING FREE FLAP PEDICLE LENGTH WITH INTERPOSITION VEIN GRAFTS AND ARTERIOVENOUS LOOPS

PURPOSE: The purpose of this study is to assess clinical outcomes for utilization of vein grafts and arteriovenous loops in the context of free flap reconstruction. Free tissue transfer in complex oncological and traumatic defects may require extension of the vascular pedicle to reach recipient vessels and complete microvascular anastomosis. This can be accomplished by using vein grafts as a bridging medium. When interposition vein grafts (IVG) are needed for extension of both the arterial and venous conduit, a temporary arteriovenous fistula (AV loop) can be constructed as an intermediary step. These techniques have traditionally been regarded with increased risk of thrombosis and flap failure, but the body of clinically relevant published data lags behind.

Vascularized Bone Grafting for Reconstruction of Oncologic Defects in the Spine: A Systematic Review and Pooled Analysis of the Literature

Background Resection of primary spinal tumors requires reconstruction for restoration of spinal column stability. Traditionally, some combination of bone grafting and instrumentation is implemented. However, delayed healing environments are associated with pseudoarthrodesis and failure. Implementation of vascularized bone grafting (VBG) to complement hardware may present a solution. We evaluated the use of VBG in oncologic spinal reconstruction via systematic review and pooled analysis of literature. Methods We searched PubMed/MEDLINE, Embase, Cochrane, and Scopus for studies published through September 2017 according to the PRISMA guidelines and performed a pooled analysis of studies with n > 5. Additionally, we performed retrospective review of patients at the Johns Hopkins Hospital that received spinal reconstruction with VBG. Results We identified 21 eligible studies and executed a pooled analysis of 12. Analysis indicated an 89% (95% confidence interval [CI]: 0.75‐1.03) rate of successful union when VBG is employed after primary tumor resection. The overall complication rate was 42% (95% CI: 0.23‐0.61) and reoperation rate was 27% (95% CI: 0.12‐0.41) in the pooled cohort. Wound complication rate was 18% (95% CI: 0.11‐0.26). Fifteen out of 209 patients (7.2%) had instrumentation failure and mean time‐to‐union was 6 months. Consensus in the literature and in the patients reviewed is that introduction of VBG into irradiated or infected tissue beds proves advantageous given decreased resorption, increased load bearing, and faster consolidation. Downsides to this technique included longer operations, donor‐site morbidity, and difficulty in coordinating care. Conclusions Our results demonstrate that complication rates using VBG are similar to those reported in studies using non‐VBG for similar spinal reconstructions; however, fusion rates are better. Given rapid fusion and possible hardware independence, VBG may be useful in reconstructing defects in patients with longer life expectancies and/or with a history of chemoradiation and/or infection at the site of tumor resection.

Abstract P28: Nanofiber-Hydrogel Composite with Human Adipose-Derived Stem Cells to Enable Soft Tissue Regeneration

PSRC Abstract Supplement P oter P rofs transection without repair. First, we evaluated the extensor digitorum longus (EDL) muscles of 15 adult wildtype C57BL/6 mice (n=3 per time point) at days 1, 3, 5, 7, and 14 after sciatic nerve injury. The uninjured EDL muscles served as the experimental controls. These muscles were harvested for immunostaining with CD68 (monocytes/ macrophages) and DAPI (nuclear) staining. Next, using the same injury and mouse model, flow cytometry was utilized to evaluate total cells present in EDL muscle after sciatic nerve injury. Animals were sacrificed at days 1 and 5 after nerve injury, and all muscles of the hindlimb innervated by the sciatic nerve were harvested from the right injured and left uninjured legs. Cells were analyzed following muscle digestion.

Proximal femur reconstruction using a vascularized fibular epiphysis within a cadaveric femoral allograft in a child with Ewing sarcoma: a case report

Periarticular reconstruction of appendicular bones in skeletally immature patients after tumor resection is a surgical challenge that requires a multidisciplinary approach. The authors present a case of Ewing sarcoma of the proximal femur in an 8-year old girl treated with wide resection of the primary tumor and reconstruction using a vascularized fibula epiphyseal autograft within a cadaveric femoral allograft. The native femoral head was preserved to restore articular anatomy. Postoperative course was without complications. This report demonstrates the use of a vascularized fibula autograft within a cadaveric femoral allograft to optimize growth potential and joint durability in a pediatric patient. ABSTRACT