CUSTOM-MADE MEGAPROSTHESES IN PATIENTS WITH MALIGNANT TUMORS OF THE PELVIS: 31 YEARS OF EXPERIENCE AND RESULTS

Introduction: Surgical treatment options of malignant tumors of the pelvis were traditionally very limited, and often resulted in an amputation. With development of neo/-adjuvant therapies, limb-salvage surgery has become the treatment of choice. Still, the treatment remains challenging, and options for pelvic reconstruction after resection such as allografts, radiated autografts, saddle-prosthesis, custom made prosthesis and modular reconstruction systems are all associated with high complication rates. Aim of our retrospective study was to evaluate the results after reconstruction of the pelvis with a custom-made pelvic megaprosthesis. Materials and Methods: From 1977 to 2008, a total of 92 patients with malignant tumors or metastases of the pelvis were treated by resection and reconstruction with custom-made pelvic megaprostheses at our institution. Mean age was 56.2 years [17–77] with 43 male patients and 59 female. We treated 45 primary tumors and 47 metastases. Primary tumors included chondrosarcoma (45,4%), Ewing’s sarcoma (18,2%), malignant fibrous histiocytoma (9,1%), osteosarcoma (4,5%) and others. In the group with metastases we found renal cell carcinoma (52,4%), mamma-carcinoma (14,3%), thyroid carcinoma (9,5%), oropharyngeal carcinomas (9,5%), and others. Wide resection was performed in 11 patients, marginal-resection in 47, and intralesional-resection in 34 patients. Depending on the bone defect after tumor resection, pelvic megaprostheses were implanted either in the superior part of the iliac wing, the sacrum and/or the lower lumbar spine. Results: Patients were reassessed repeatedly at two different time points resulting in a mean follow-up of 3,6 years [range 0,5 to 8,4years]. A total of 55 patients were available for follow-up, 29 had died and 6 Patients were not available for evalutation (living abroad). In the group with malignant tumors 50% of the patients were alive after 5 years; 50% of patients with metastasis survived at least 2 years. The local recurrence rate was 15%. In 2 of these patients local re-resection was possible, and 5 patients were treated with secondary external hemi-pelvectomy. Aseptic failure of the megaprosthesis was observed in 3%. The MSTS-Score showed good results in 34%, fair results in 42% and poor results in 23%. We found infections in 14%. Nerve palsy occurred in 11%, thombosis in 5%, and dislocation of the prosthesis in 15% of patients. Discussion: Our study demonstrates that reconstruction of pelvic bone defects after tumor resection with custom-made megaprosthesis allows limb-salvage surgery with satisfying functional results. In spite of the relatively high complication rates-which are comparable or even favorable to other reconstruction techniques-we consider the custom-made megaprosthesis our treatment of choice to reconstruct pelvic bone defects.