Background: Limb-salvage surgery has been well recognized as a standard treatment and alternative to amputation for\r\npatients with malignant bone tumors. Various limb-sparing techniques have been developed including tumor prosthesis,\r\nallograft, autograft and graft-prosthesis composite. However, each of these methods has short- and long-term\r\ndisadvantages such as nonunion, mechanical failures and poor limb function. The technique of intracorporeal devitalization\r\nof tumor-bearing bone segment in situ by microwave-induced hyperthermia after separating it from surrounding normal\r\ntissues with a safe margin is a promising limb-salvage method, which may avoid some shortcomings encountered by the\r\nabove-mentioned conventional techniques. The purpose of this study is to assess the healing process and revitalization\r\npotential of the devitalized bone segment by this method in a dog model. In addition, the immediate effect of microwave\r\non the biomechanical properties of bone tissue was also explored in an in vitro experiment.\r\nMethods: We applied the microwave-induced hyperthermia to devitalize the distal femurs of dogs in situ. Using a\r\nmonopole microwave antenna, we could produce a necrotic bone of nearly 20 mm in length in distal femur. Radiography,\r\nbone scintigraphy, microangiography, histology and functional evaluation were performed at 2 weeks and 1, 2, 3, 6, 9 and\r\n12 months postoperatively to assess the healing process. In a biomechanical study, two kinds of bone specimens, 3 and\r\n6 cm in length, were used for compression and three-point bending test respectively immediately after extracorporeally\r\ndevitalized by microwave.\r\nFindings: An in vivo study showed that intracorporeally and in situ devitalized bone segment by microwave had great\r\nrevitalization potential. An in vitro study revealed that the initial mechanical strength of the extracorporeally devitalized\r\nbone specimen may not be affected by microwave.\r\nConclusion: Our results suggest that the intracorporeal microwave devitalization of tumor-bearing bone segment in situ\r\nmay be a promising limb-salvage method.
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