Guo Zehao, Peng Yongjun, Shen Qiling, Li Jian, He Peng, Yuan Peng, Liu Yulei, Que Yukang, Guo Wei, Hu Yong, Xu Shenglin
Department of Orthopedics, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China.
Musculoskeletal Tumor Center, Peking University People's Hospital, Beijing, China.
Front Bioeng Biotechnol. 2023 Jan 9;10:1036882. doi: 10.3389/fbioe.2022.1036882. eCollection 2022.
Prosthetic reconstruction after type I + II+ III internal hemipelvectomy remains challenging due to the lack of osseointegration and presence of giant shear force at the sacroiliac joint. The purpose of this study was to evaluate the biomechanical properties of the novel 3D-printed, custom-made prosthesis with pedicle screw-rod system and sacral tray using finite element analysis. Four models that included one intact pelvis were established for validation. Forces of 500 N and 2,000 N were applied, respectively, to simulate static bipedal standing and the most loaded condition during a gait cycle. Biomechanical analysis was performed, and the results were compared; the preliminary outcomes of four patients were recorded. For the reconstructed hemipelvis, stress was mainly concentrated on the sacral screws, bone-prosthesis interface, and upper endplate of the L5 vertebra. The optimization of the design with the sacral tray structure could decrease the peak stress of the sacral screws by 18.6%, while the maximal stress of the prosthesis increased by 60.7%. The addition of the lumbosacral pedicle-rod system further alleviated stress of the sacral screws and prosthesis by 30.2% and 19.4%, respectively. The site of peak stress was contemporaneously transferred to the connecting rods within an elastic range. In the retrospective clinical study, four patients who had undergone prosthetic reconstruction were included. During a follow-up of 16.6 ± 7.5 months, the walking ability was found preserved in all patients who are still alive and no prosthesis-related complications had occurred except for one hip dislocation. The Musculoskeletal Tumor Society (MSTS) score was found to be 19.5 ± 2.9. The novel reconstructive system yielded favorable biomechanical characteristics and demonstrated promising preliminary outcomes. The method can be used as a reference for reconstruction after type I + II + III hemipelvectomy.
由于缺乏骨整合以及骶髂关节处存在巨大剪切力，I型+II型+III型半骨盆切除术之后的假体重建仍然具有挑战性。本研究的目的是使用有限元分析评估新型3D打印定制假体（带椎弓根螺钉-棒系统和骶骨托）的生物力学特性。建立了包括一个完整骨盆在内的四个模型用于验证。分别施加500 N和2000 N的力来模拟静态双足站立和步态周期中负荷最大的情况。进行生物力学分析并比较结果；记录了四名患者的初步结果。对于重建的半骨盆，应力主要集中在骶骨螺钉、骨-假体界面和L5椎体的上端板。采用骶骨托结构进行设计优化可使骶骨螺钉的峰值应力降低18.6%，而假体的最大应力增加60.7%。添加腰骶椎弓根-棒系统可分别使骶骨螺钉和假体的应力进一步减轻30.2%和19.4%。峰值应力部位在弹性范围内同时转移至连接杆。在回顾性临床研究中，纳入了四名接受假体重建的患者。在16.6±7.5个月的随访期间，发现所有存活患者的行走能力均得以保留，除一例髋关节脱位外未发生与假体相关的并发症。肌肉骨骼肿瘤学会（MSTS）评分为19.5±2.9。这种新型重建系统具有良好的生物力学特性，并显示出有前景的初步结果。该方法可作为I型+II型+III型半骨盆切除术后重建的参考。
