Murakami Hideki, Kawahara Norio, Tomita Katsuro, Sakamoto Jiro, Oda Juhachi
Department of Orthopaedic Surgery, Kanazawa University, 13-1 Takaramachi, Kanazawa 920-8641, Japan.
J Orthop Sci. 2002;7(6):658-64. doi: 10.1007/s007760200117.
When a sacral tumor involves the first sacral vertebra, total sacrectomy is necessary. It is mandatory to reconstruct the continuity between the spine and the pelvis after total sacrectomy. In this study, strain and stress on the instruments and the bones were evaluated for two reconstruction methods: a modified Galveston reconstruction (MGR) and a triangular frame reconstruction (TFR). Compressive loading tests were performed using polyurethane vertebral models, and a finite element model of a lumbar spine and pelvis was constructed. Then three-dimensional MGR and TFR models were reconstructed, and finite element analysis was performed to account for the stress on the bones and instruments. With MGR, excessive stress was concentrated at the spinal rod, and there was a strong possibility that the rod between the spine and the pelvis might fail. Although there was no stress concentration on the instruments with TFR, excessive stress on the iliac bone around the sacral rod was more than the yielding stress of the iliac bone. Such stress may cause loosening of the sacral rod from the iliac bone. If the patient were to stand or sit immediately after MGR or TFR, instrumentation failure or loosening might occur.
当骶骨肿瘤累及第一骶椎时，全骶骨切除术是必要的。全骶骨切除术后重建脊柱与骨盆之间的连续性是必须的。在本研究中，针对两种重建方法评估了器械和骨骼上的应变与应力：改良加尔维斯顿重建法（MGR）和三角框架重建法（TFR）。使用聚氨酯椎体模型进行压缩载荷试验，并构建腰椎和骨盆的有限元模型。然后重建三维MGR和TFR模型，并进行有限元分析以计算骨骼和器械上的应力。采用MGR时，过大的应力集中在脊柱棒上，脊柱与骨盆之间的棒很有可能失效。虽然TFR在器械上没有应力集中，但骶骨棒周围髂骨上的过大应力超过了髂骨的屈服应力。这种应力可能导致骶骨棒从髂骨上松动。如果患者在MGR或TFR后立即站立或坐下，可能会发生器械失效或松动。
