[Reconstruction of the pelvic ring based on classification following resection of bone tumors]

Bone tumors in the pelvis (28 cases), which had been treated surgically were classified into types I to V and their subtypes A and B, according to the location and range of tumor resection, and were assessed with regard to both the method of reconstruction used and restoration of function. Type I-A, -B (6 cases) did not require any reconstruction of the pelvic ring. However, with type I -B, some difficulty was experienced in maintaining balance upon sitting for a long period. Type II (3 cases) included cases of resection of the anterior part of the pelvis, resulting in loss of ring continuity, but reconstruction was not necessary. In type III -A, the acetabulum excluding the hip joint (1 case) was resected and arthrodesis of the ilium and the femoral head performed. In type III -B the acetabulum with the hip joint was resected (2 cases) followed by replacement of the pelvis and hip joint with an artificial prosthesis. Type N included cases (5) of partial (-A) or total (-B) sacroiliac resection, both of which needed massive bone grafting to reconstruct the pelvic ring. Type V (7 cases) required partial (A) or total (B), resection of the sacrum dynamic reconstruction by spinal instrumentation and massive bone grafting. Among 13 cases of primary malignant bone tumors for which tumor resection was performed, 3 cases recurred. This classification was useful for comparing the surgical modalities of tumor resection, reconstruction and their functional results. Our method of total sacral resection was also introduced.