Browsing by Author "Levin, L Scott"

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    Interstitial engraftment of adipose-derived stem cells into an acellular dermal matrix results in improved inward angiogenesis and tissue incorporation.
    (J Biomed Mater Res A, 2013-10) Komatsu, Issei; Yang, Jun; Zhang, Ying; Levin, L Scott; Erdmann, D; Klitzman, Bruce; Hollenbeck, Scott T
    Acellular dermal matrices (ADM) are commonly used in reconstructive procedures and rely on host cell invasion to become incorporated into host tissues. We investigated different approaches to adipose-derived stem cells (ASCs) engraftment into ADM to enhance this process. Lewis rat adipose-derived stem cells were isolated and grafted (3.0 × 10(5) cells) to porcine ADM disks (1.5 mm thick × 6 mm diameter) using either passive onlay or interstitial injection seeding techniques. Following incubation, seeding efficiency and seeded cell viability were measured in vitro. In addition, Eighteen Lewis rats underwent subcutaneous placement of ADM disk either as control or seeded with PKH67 labeled ASCs. ADM disks were seeded with ASCs using either onlay or injection techniques. On day 7 and or 14, ADM disks were harvested and analyzed for host cell infiltration. Onlay and injection techniques resulted in unique seeding patterns; however cell seeding efficiency and cell viability were similar. In-vivo studies showed significantly increased host cell infiltration towards the ASCs foci following injection seeding in comparison to control group (p < 0.05). Moreover, regional endothelial cell invasion was significantly greater in ASCs injected grafts in comparison to onlay seeding (p < 0.05). ADM can successfully be engrafted with ASCs. Interstitial engraftment of ASCs into ADM via injection enhances regional infiltration of host cells and angiogenesis, whereas onlay seeding showed relatively broad and superficial cell infiltration. These findings may be applied to improve the incorporation of avascular engineered constructs.
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    The vascularized fibular graft in the pediatric upper extremity: a durable, biological solution to large oncologic defects.
    (Sarcoma, 2013-01) Zelenski, Nicki; Brigman, Brian E; Levin, L Scott; Erdmann, Detlev; Eward, William C
    Skeletal reconstruction after large tumor resection is challenging. The free vascularized fibular graft (FVFG) offers the potential for rapid autograft incorporation as well as growing physeal transfer in pediatric patients. We retrospectively reviewed eleven pediatric patients treated with FVFG reconstructions of the upper extremity after tumor resection. Eight male and three female patients were identified, including four who underwent epiphyseal transfer. All eleven patients retained a functional salvaged limb. Nonunion and graft fracture were the most common complications relating to graft site (27%). Peroneal nerve palsy occurred in 4/11 patients, all of whom received epiphyseal transfer. Patients receiving epiphyseal transplant had a mean annual growth of 1.7 cm/year. Mean graft hypertrophy index increased by more than 10% in all cases. Although a high complication rate may be anticipated, the free vascularized fibula may be used to reconstruct large skeletal defects in the pediatric upper extremity after oncologic resection. Transferring the vascularized physis is a viable option when longitudinal growth is desired.
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    Vascularized Fibula-Based Physis Transfer: A Follow-Up Study of Longitudinal Bone Growth and Complications.
    (Plastic and reconstructive surgery. Global open, 2017-05-25) Shammas, Ronnie L; Avashia, Yash J; Farjat, Alfredo E; Catanzano, Anthony A; Levin, L Scott; Eward, William C; Brigman, Brian E; Erdmann, Detlev

    Background

    The vascularized free fibula epiphyseal transfer provides an option for the preservation of limb lengthening after resection of the proximal humerus in pediatric sarcoma patients. The purpose of this study was to provide a long-term follow-up of longitudinal growth patterns and outcomes after free fibula epiphyseal transfer in upper extremity reconstruction.

    Methods

    A retrospective review of 4 patients who underwent free fibula epiphyseal transfer after oncologic resection of the proximal humerus for osteosarcoma was performed. Oncologic details that could affect outcomes were included in the review: primary tumor pathology, location of malignancy, and presence of recurrence. Details on the reconstruction included longitudinal growth of the flap from the time of implantation to the most recently available radiograph and postoperative complications. The length of the fibula over time was measured from the humeral head to the olecranon process.

    Results

    All patients were alive at the start of this study. The average longitudinal growth rate of the free fibula epiphyseal transfer was 0.54 ± 0.18 cm/y, and patients demonstrated satisfactory and consistent longitudinal bone growth and hypertrophy over time. All 4 patients suffered from a complication of postoperative fibula graft fracture, and 1 of 4 patients experienced unremitting peroneal nerve damage. All patients demonstrated normal wrist and hand motion with a normal arc of elbow flexion and extension.

    Conclusion

    This study demonstrates that the vascularized fibula epiphyseal transfer offers the ability to preserve longitudinal limb growth and hypertrophy throughout adolescence.