[Integration of modern technologies in therapy of sarcomas of the pelvis. Computer-assisted hemipelvectomy and implantation of a "custom-made" Bonit gentamycin coated partial pelvic prosthesis].

The resection of primary malignancies in the pelvis is technically demanding as organs and structures are to be preserved and reconstruction of the defect as well as the postoperative function and rehabilitation are dependent on an optimal prosthesis. We present two patients with a sarcoma of the pelvis where for the first time a structured concept of technology integration led to a press-fit implantation of a hemipelvic prosthesis. This concept includes the design and production of a "custom-made" prosthesis as a hemipelvic substitute and the coating of this prosthesis with Bonit, a second-generation calcium phosphate, and gentamycin in watery solution. The tumor resection was done with computer-assisted surgery based on computed tomographies (CT) of the pelvis model done by rapid prototyping rather than on the CT of the patients' pelvis. With this procedure the presurgically simulated resection could be executed precisely with complete resection of the tumors and an accuracy which allowed an exact implantation of the prosthesis. The course was uneventful with primary healing and no sign of an infection or loosening after 6 months.