Objective To investigate the value of computer-aided design (CAD) in defining the resection boundary, reconstructing the pelvis and hip in patients with pelvis tumors. Methods Between November 2006 and April 2009, 5 cases of pelvis tumors were treated surgically using CAD technology. There were 3 males and 2 females with an average age of 36.4 years (range, 24-62 years). The cause was osteosarcoma, giant cell tumor of bone, and angiosarcoma in 1 case, respectively,and chondrosarcoma in 2 cases. According to the Enneking system for staging benign and mal ignant musculoskeletal tumors, regions I, I + II, III, IV, and I + IV is in 1 case, respectively. According to the principle of reverse engineering, 5 patients with pelvis tumors were checked with lamellar CT/MRI scanning, whose two-dimensional data were obtained in disease area. The three-dimensional reconstruction of pelvic anatomical model, precise resection boundary of tumor, individual surgical template, individual prosthesis, and surgical simulation were precisely made by computer with CAD software. Based on the proposal of CAD, the bone tumor was resected accurately, and allograft il ium with internal fixation instrument or allogeneic il ium with personal ized prosthetic replacement were used to reconstruct the bone defect after tumor was resected. Results The operation was successfully performed in 5 cases. The average operation time was 7.9 hours, and the average blood loss was 3 125 mL. Hemorrhage and cerebrospinal fluid leakage occurred in 1 case, respectively, and were cured after debridement. Five patients were followed up from 24 to 50 months (mean, 34.5 months). All patients began non-weight bearing walk with double crutches at 4-6 weeks after operation, and began walk at 3-6 months after operation. Local recurrence developed in 2 patients at 18 months after operation, and resection and radiotherapy were performed. According to International Society of Limb Salvage criteria for curative effectiveness of bone tumor l imb salvage, the results were excellent in 2 and good in 3. Conclusion The individual surgical template, individual prosthesis, and surgical simulation by CAD ensure the precision and rel iabil ity of pelvis tumors resection. The CAD technology promotes pelvis tumor resection and the reconstruction of pelvis to individual treatment stage, and good curative effectiveness can be obtained.
Objective To improve the fitness and initial fixation strength between the hip and bone and to optimize the shape of the prosthetic implants. Methods The cross-section of hip canal was automatically extracted by Image processing. By using taper curve fit,hypocurve predigesting and the curve of shape center fit, the parameters of long-short diameter and the curve of shape center were got to design the hip shape.CAD was adopted to analyze and evaluate the configuration of bone and shape of hip.The “peg-in-hole” was employed to optimize the shape of implant by the visual test of “Drawingout” in computer. Results 23.2% hip-bone average matching rate and 0.033% bone damage rate were presented by CAD analysis. The implant extraction path were validated visually and quantitatively by measuring the maximum amount of overlap in the path configuration. Conclusion The valuable method for prothsetic hip design was presented by the way of image processing,graphics design and optimizingdesign in this study.
Objective To compare the effect of three-dimensional visual (3DV) model, three-dimensional printing (3DP) model and computer-aided design (CAD) modified 3DP model in video-assisted thoracoscopic surgery (VATS) sublobular resection. MethodsThe clinical data of patients who underwent VATS sublobular resection in the Affiliated Hospital of Hebei University from November 2021 to August 2022 were retrospectively analyzed. The patients were divided into 3 groups including a 3DV group, a 3DP group and a CAD-3DP group according to the tools used. The perioperative indexes and subjective evaluation of operators, patients and their families were compared. ResultsA total of 22 patients were included. There were 5 males and 17 females aged 32-77 (56.95±12.50) years. There were 9 patients in the 3DV group, 6 patients in the 3DP group, and 7 patients in the CAD-3DP group. There was no statistical difference in the operation time, intraoperative blood loss, drainage volume, hospital stay time or postoperative complications among the groups (P>0.05). Based on the subjective evaluations of 4 surgeons, the CAD-3DP group was better than the 3DV group in the preoperative planning efficiency (P=0.025), intuitiveness (P=0.045) and doctor-patient communication difficulty (P=0.034); the CAD-3DP group was also better than the 3DP group in the overall satisfaction (P=0.023), preoperative planning difficulty (P=0.046) and efficiency (P=0.014). Based on the subjective evaluations of patients and their families, the CAD-3DP group was better than the 3DP group in helping understand the vessel around the tumor (P=0.016), surgical procedure (P=0.020), procedure selection (P=0.029), and overall satisfaction (P=0.048); the CAD-3DP group was better than the 3DV group in helping understand the tumor size (P=0.038). ConclusionCAD-modified 3DP model has certain advantages in pre-planning, intraoperative navigation and doctor-patient communication in the VATS sublobectomy.