Giant cell tumor of bone with pulmonary metastases.
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Biomedical subjects
Publications and source records attributed to Michael D Neel.
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Limb salvage for management of osteosarcoma of the lower extremity has become the mainstay of treatment for patients with malignant bony and soft tissue tumors. The knee has become a special area of concern for the reconstructive surgeon due to the high rate of wound complications and difficulties of soft tissue reconstruction. With the availability of new prosthetic implants, the advancement of surgical soft tissue techniques and introduction of adjuvant and neoadjuvant chemotherapy, resection and reconstruction has become the standard approach for patients presenting to St. Jude Children's Research Hospital. The pediatric plastic surgeon's role usually requires handling of wound complications in these reconstructive procedures. This article will discuss the authors' approach to dealing with wound complications in this difficult patient population and their interaction with the orthopedic oncologic service in obtaining primary resection and soft tissue coverage.
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A noninvasive expandable prosthesis for skeletally immature children after limb salvage surgery has been developed. Between 1998 and 2001, 18 Phenix prostheses were implanted in 15 pediatric patients who had been diagnosed and treated for osteosarcoma about the knee. Of the 15 original prostheses, 10 were implanted at the time of primary tumor resection and five were revisions from an endoprosthetic modular knee system. Sixty expansions of the 18 prostheses were done, with all but two done as outpatient procedures. An average 8.5 mm was obtained per lengthening (range, 1-30 mm). The average followup was 21.5 months (range, 12-33 months) and the latest Musculoskeletal Tumor Society functional scores averaged 90%. Eight revisions were required for stem fracture or loosening. There was one amputation because of a postoperative arterial thrombosis. The principle of the Phenix prosthesis involves storage of energy in a spring compressed by a locking system. Lengthening is achieved via exposure to an electromagnetic field that allows controlled release of the spring. This is a unique expandable custom prosthesis that offers many benefits in maintaining limb length equality in growing patients. Although the early experience is promising, additional data are required regarding the long-term structural integrity of the prosthesis. We are optimistic that this technology will prove beneficial, not only for patients with malignant bone tumors but in applications requiring serial limb length equalizations or for spinal deformities.
Treatment with isolated allogeneic mesenchymal cells has the potential to enhance the therapeutic effects of conventional bone marrow transplantation in patients with genetic disorders affecting mesenchymal tissues, including bone, cartilage, and muscle. To demonstrate the feasibility of mesenchymal cell therapy and to gain insight into the transplant biology of these cells, we used gene-marked, donor marrow-derived mesenchymal cells to treat six children who had undergone standard bone marrow transplantation for severe osteogenesis imperfecta. Each child received two infusions of the allogeneic cells. Five of six patients showed engraftment in one or more sites, including bone, skin, and marrow stroma, and had an acceleration of growth velocity during the first 6 mo postinfusion. This improvement ranged from 60% to 94% (median, 70%) of the predicted median values for age- and sex-matched unaffected children, compared with 0% to 40% (median, 20%) over the 6 mo immediately preceding the infusions. There was no clinically significant toxicity except for an urticarial rash in one patient just after the second infusion. Failure to detect engraftment of cells expressing the neomycin phosphotransferase marker gene suggested the potential for immune attack against therapeutic cells expressing a foreign protein. Thus, allogeneic mesenchymal cells offer feasible posttransplantation therapy for osteogenesis imperfecta and likely other disorders originating in mesenchymal precursors.