[Osteosarcoma of the pelvisTwo case reports and review of the literature]. / Osteosarkome des SakrumsZwei Fallbeispiele und Literaturübersicht.

Primary malignant neoplasms of the bone are rare. One of the most common bone tumors is osteosarcoma, most often localized in the metaphysis of adolescent long bones. The sacrum is concerned in only about 1%. Primary bone sarcomas of the pelvis are usually recognized after they have grown to a considerable size. Osteosarcoma patients from Germany, Austria, and Switzerland are treated by neoadjuvant chemotherapy combined with complete surgical excision according to the Cooperative Osteosarcoma Study Group (COSS). Based on a review of the literature, diagnosis, treatment, and complications of two cases of sacrum osteosarcoma are introduced.

[Surgical treatment of osseous metastases of the pelvis]. / Operative Behandlung von Metastasen des knöchernen Beckens.

Metastases are the most frequent malignant tumors of the skeleton. Breast cancer is the most frequent primary tumor with osseous metastases followed by renal cell carcinomas, bronchial carcinomas, and thyroid tumors. The predominant localization of bone metastases is the spine, followed by the pelvis, femur, ribs, skull, sternum, and humerus. The overall incidence of bone metastases has increased due to improved diagnosis, prolonged survival by adjuvant therapy, and improved follow-up. Osseous metastases of the pelvis are usually diagnosed only late in the course of the disease because of their considerable delayed onset of clinical symptoms. Therefore, treatment is usually focused on a palliative approach to reduce pain and to improve the quality of life. We introduce three patients with bronchial, renal cell, and cholangiocellular carcinoma in an incurable tumor stage with osseous metastases in the pelvis. The metastatic osteolyses caused pain and symptoms of instability. Despite high doses of opiate analgesics, the patients were neither free of pain nor could they be mobilized. The palliative treatment included preoperative tumor embolization followed by tumor resection and implantation of a hip prosthesis. The preoperative embolization reduced intraoperative bleeding and made tumor resection, osteosynthesis, and implantation of the hip prosthesis possible. Mobilization with moderate pain could be achieved in these three patients for the rest of their lives.

[Reosteosynthesis in dens pseudarthrosis. Case report and review of the literature]. / Zur Problematik der Reosteosynthese bei Denspseudarthrose. Fallbericht und Literatursammlung.

According to general recommendations, unstable nonunions of the odontoid are treated by posterior fusion of the segments C1/C2 and transarticular screwosteosynthesis. The aim of the surgical procedure is to obtain secure reduction stabilization, and fusion of the nonunion. We present a case of secondary atlanto-axial instability treatment following of an odontoid nonunion. In this situation stability of C1/C2 was achieved by atlanto-axial fusion by transarticular screw fixation. The ventral parts of the broken implants were left in place. Diagnosis, treatment and complications of pseudarthrosis of the dens axis are discussed in the context of this case and of literature.

[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]. / Integration moderner Technologien bei der Therapie von Sarkomen des Beckens. Computerassistierte Hemipelvektomie und Implantation eines "custom-made" Bonit-Gentamycin-beschichteten Beckenteilersatzes.

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.