| ObjectiveTo investigate an effective method to reconstruct acetabular defect using customprosthesis after tumor En-bloc resection with the help of computer assisted navigationsystem (CANS).Methods3D model of image fusion was reconstructed using the preoperative CT and MRIdata. The tumor invasion range, the safe resection boundaries and osteotomy planes weremarked on the3D model. A custom acetabular prosthesis was designed and manufacturedusing CAD/CAM techniques according to pelvic defects. With the help of CANS, thetumor was accurately resected and the custom prosthesis was fixed precisely according to the preoperative planning. We formulated the innovative treatment process. BetweenDecember2010and May2012,3patients with primary malignant acetabular tumorunderwent the treatment process．They were males，aged from30to55years (average,41.3years)． There were2cases of chondrosarcoma and1case of primitiveneuroectodermal tumor (PNET)．The Enneking stage of periacetabular tumor was ⅡB inall of cases. All3patients were followed up, and complications, MSTS score andprognosis were recorded.ResultsThree-dimensional (3D) models were reconstructed according to pre-operative CTand MRI data in3cases. The area of tumor invasion was displayed using MRI-CT imagefusion technique, and the safe margin of tumor resection was planned preoperatively. Twokinds of custom prosthesis were designed and the manufacture time was shortened from30d to7d. The parameters were imported into the CANS preoperatively for the purpose ofaccurate resection and precise reconstruction. After point and surface matching, the meandistance error of registration was from0.71to0.85mm (average,0.78mm). Theperiacetabular tumors in all3cases were resected successfully，and the bone defects werereconstructed precisely with custom prosthesis．The second patient suffered dislocation ofthe hip joint postoperative because of being wrong moved, and then underwent closedreduction. The patient presented symptom of deep venous thrombosis in lower limb whichdisappeared after treatment. All the3patients were followed up for10to21months. Atthe final follow-up,3patients survived free of recurrence. No such complications as deepinfection, dislocation, prosthesis loosening and screw broken occurred during thefollow-up period. The MSTS score was18～26．ConclusionThe process is effective for treatment of periacetabular tumors. Pericetabular tumorcan be En-bloc resected safely and custom prosthesis can be fixed precisely with the helpof CANS. According to the process, accurate tumor resection and precise reconstructioncan be achieved. The method has a low rate of complications. The short-term result is fine,while the long-term result needs further observation．... |
