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Tomoki Nakamura,1 Jun Sugaya,2 Norifumi Naka,3 Hiroshi Kobayashi,4 Tomotake Okuma,5 Toshiyuki Kunisada,6 Kunihiro Asanuma,1 Hedetatsu Outani,7 Shunji Nishimura,8 Hiroyuki Kawashima,9 Toru Akiyama,10 Taketoshi Yasuda,11 Shinji Miwa,12 Akihiro Sudo,1 Takafumi Ueda13 1Department of Orthopaedic Surgery, Mie University Graduate School of Medicine, Tsu 514-8507, Japan; 2Department of Musculoskeletal Oncology, National Cancer Center Hospital, Chuo-ku, Tokyo 104-0045, Japan; 3Musculoskeletal Oncology Service, Osaka International Cancer Institute, Chuo-ku, Osaka 541-8567, Japan; 4Department of Orthopaedic Surgery, The University of Tokyo Hospital, Bunkyo-ku, Tokyo 113-8655, Japan; 5Department of Musculoskeletal Oncology, Tokyo Metropolitan Cancer and Infectious Diseases Center, Komagome Hospital, Bunkyo-ku, Tokyo 113-8677, Japan; 6Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama 700-8558, Japan; 7Department of Orthopaedic Surgery, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871, Japan; 8Department of Orthopaedic Surgery, Kindai University Hospital, Osaka-Sayama, Osaka 589-8511, Japan; 9Division of Orthopaedic Surgery, Niigata University Graduate School of Medical and Dental Sciences, Chuo-ku, Niigata 951-8510, Japan; 10Department of Orthopaedic Surgery, Saitama Medical Center, Jichi Medical University, Saitama, Saitama 330-8503, Japan; 11Department of Orthopaedic Surgery, University of Toyama, Toyama 930-0194, Japan; 12Department of Orthopaedic Surgery, Kanazawa University Graduate School of Medical Sciences, Kanazawa 920-8641, Japan; 13Department of Orthopaedic Surgery, Osaka National Hospital, Chuo-ku, Osaka 540-0006, JapanCorrespondence: Tomoki NakamuraDepartment of Orthopedic Surgery, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie 514-8507, JapanTel +81-592315022Fax +81-592315211Email tomoki66@clin.medic.mie-u.ac.jpBackground: The outcomes of unplanned surgery for bone sarcomas have not been frequently discussed. However, it is important to recognize patterns, treatment, and clinical outcomes of unplanned surgeries for patients with bone sarcomas. This multicenter study aimed to characterize the clinical outcomes of patients with bone sarcomas who underwent unplanned surgeries.Patients and Methods: Data of 43 patients with bone sarcomas who underwent unplanned surgery between 2006 and 2017 were obtained from 23 hospitals in Japan. These included 18 cases of osteosarcoma, 9 of Ewing sarcoma, 8 of chondrosarcoma, and 6 of undifferentiated pleomorphic sarcoma. The study included 28 men and 15 women, with a mean age of 46 years. The mean follow-up duration was 59 months.Results: The main primary tumor sites were the femur (n = 19), spine (n = 6), pelvis (n = 5), tibia (n = 3), and humerus (n = 3). The primary diagnoses were benign bone tumor (n = 24), trauma (n = 7), bone metastasis (n = 5), osteomyelitis (n = 4), degeneration (n=2), and unknown (n = 1). As unplanned surgeries, curettage, with or without bone graft, was performed in 26 patients; internal fixation was performed in 7; spinal surgery in 5; arthroplasty in 4; and arthroscopy in one. Thirty-eight patients received additional standard treatments. Thirty-four of these patients underwent surgical tumor resections, including amputation (n = 10), and the remaining 4 received radiotherapy or carbon ion radiotherapy as additional standard treatments. The 5-year disease-specific survival (DSS) rates in patients with osteosarcoma, Ewing sarcoma, and chondrosarcoma were 65.5%, 58.3%, and 72.9%, respectively. Twelve (27.9%) patients developed local recurrences (LR); among the total 43 patients studied, the 5-year DSS rates were significantly worse for those who developed LR compared to those who did not (p = 0.03). The 5-year DSS rates in patients with and without LR were 44% and 73.8%, respectively.Conclusion: We recommend that patients who have undergone unplanned surgery be administered standard treatment, including the option of amputation because herein, LR was shown to be a risk factor for decreased DSS.Keywords: bone sarcoma, unplanned surgery, local recurrence, osteosarcoma, Ewing sarcoma, chondrosarcoma

The present paper first proposes a new type of superconducting current limiter comprising a non-inductively wound AC superconducting coil (trigger coil) connected in parallel with a limiting coil. Furthermore, a model electric power system for the application of this type of superconducting current limiters was created, a 400V/100A class model superconducting current limiters was fabricated, and various current limiting tests were performed with respect to short-circuit currents and phases varied over a wide range. The results so obtained demonstrated that the present type of current limiter possessed performance characteristics fully adequate for application to the model system. Moreover, with a view to increased capacity, a 6.6kV/1500A class superconducting trigger coil was developed, with a scale permitting, in principle, validation tests of applicability to actual power systems. This coil was demonstrated to be capable of limiting short-circuit currents by a factor of 1/30, and was subjected to detailed evaluation of current limiting characteristics.