Sun Y, Guo Y, Li J, Liu L, Yang D, Chen M, Hu K
Department of Oral and Maxillofacial Surgery, First Affiliated Hospital of Bengbu Medical College, Bengbu 233004, China.
Nan Fang Yi Ke Da Xue Xue Bao. 2021 Dec 20;41(12):1892-1898. doi: 10.12122/j.issn.1673-4254.2021.12.20.
To evaluate of the clinical value of preoperative digital design-assisted free fibular flap for reconstruction of different types of mandibular tissue defects using three-dimensional finite element analysis.
This retrospective analysis was conducted in 48 patients undergoing reconstruction of mandibular defects following tumor resection using free fibular flaps. In 24 of the cases, digital design of free fibular flap was performed before the operation (experimental group), and the other 24 patients with digital design of the flap served as the control group. At 1 year after the surgery, the patients underwent mandibular CT examination and a 3-dimensional finite element model of the mandible was constructed using Mimics, Geomagic, Solidworks and Ansys. The stress distribution on the reconstructed mandibles with the H, L, or LCL types of defects, classified according to the HCL classification method, was determined under specific constraints and load conditions and compared between the experimental and control groups.
The operations were completed successfully in all the patients, and none of them had tumor recurrence at 1 year after the operation. On the reconstructed mandibles using free fibular flaps, the stress was concentrated mainly on the neck of the bilateral condyle, the anterior and posterior edges of the ascending mandibular ramus, and the connection between the posterior end of the fibula and the mandible. A large size of mandibular defects caused greater stress at the contralateral condyle. For L-shaped defects, the maximum stress at the healthy and ipsilateral condyle necks and transplanted fibula were significantly lower, while the stress level at the healthy side mandibular angle was significantly greater in the experimental group than in the control group ( < 0.05). For LCL type defects, the maximum stress at the contralateral condyle neck was smaller but the stress in the condyle area on the affected side, the bilateral mandibular angle area and the fibula area were all significantly greater in the experimental group than in the control group ( < 0.05).
Digital design of the free fibular flap improves the accuracy of reconstruction of mandibular defects and helps to achieve uniform stress distribution on the reconstructed mandible.
运用三维有限元分析评估术前数字化设计辅助游离腓骨瓣修复不同类型下颌骨组织缺损的临床价值。
对48例采用游离腓骨瓣修复肿瘤切除术后下颌骨缺损的患者进行回顾性分析。其中24例患者在术前进行了游离腓骨瓣的数字化设计（实验组），另外24例进行了瓣数字化设计的患者作为对照组。术后1年，患者接受下颌骨CT检查，并使用Mimics、Geomagic、Solidworks和Ansys构建下颌骨的三维有限元模型。在特定约束和载荷条件下，确定根据HCL分类方法分类的H、L或LCL型缺损的重建下颌骨上的应力分布，并在实验组和对照组之间进行比较。
所有患者手术均顺利完成，术后1年均无肿瘤复发。在使用游离腓骨瓣重建的下颌骨上，应力主要集中在双侧髁突颈部、下颌升支的前缘和后缘以及腓骨后端与下颌骨的连接处。较大尺寸的下颌骨缺损会导致对侧髁突处应力更大。对于L形缺损，实验组健康侧和同侧髁突颈部及移植腓骨处的最大应力显著较低，而健康侧下颌角处的应力水平显著高于对照组（<0.05）。对于LCL型缺损，实验组对侧髁突颈部的最大应力较小，但患侧髁突区域、双侧下颌角区域和腓骨区域的应力均显著高于对照组（<0.05）。
游离腓骨瓣的数字化设计提高了下颌骨缺损修复的准确性，并有助于在重建的下颌骨上实现均匀的应力分布。
