CNR ICMATE, National Research Council, Unit of Lecco, Via Previati 1/e, 23900, Lecco, Italy.
Istituto di BioRobotica, Scuola Superiore Sant'Anna, Viale Rinaldo Piaggio 34, 56025, Pontedera, Pisa, italy.
Med Eng Phys. 2023 Aug;118:104019. doi: 10.1016/j.medengphy.2023.104019. Epub 2023 Jul 5.
Thumb amputations leads to 50 % loss in hand functionality. To date, silicone vacuum prosthesis and autologous transplantation are the most adopted treatment solutions: nevertheless, vacuum prostheses lack in stability and cause skin issue and surgical treatment is not always accepted by patients. Osseointegrated implants were demonstrated to enhance stability, restore osseoperception and increase the time of prosthesis use. Thumb amputations present varying stump sizes: a standard size implant cannot address specificity of each patient, while a patient matched solution can meet surgeon requirements, by geometrical features of implant. The fixture presented in the current paper is the first additively manufactured patient matched osseointegrated implant for the treatment of thumb amputees. The current work aims to verify and validate a predictive finite element model (FEM) for mechanical strength of the presented fixture. FEM was demonstrated to correctly evaluate the mechanical strength of patient matched device. Minimum strength requirements were calculated in different core diameters: FEM were experimentally validated. Safety factor of 1.5 was guaranteed. Finally, considerations on performance of the prototype were carried out by means of insertion tests in Sawbones and axial pull-out force assessment. Cadaver tests to evaluate the entire procedure and production process are ongoing.
拇指截肢会导致 50%的手部功能丧失。迄今为止，硅树脂真空假体和自体移植是最常用的治疗方法：然而，真空假体缺乏稳定性，会导致皮肤问题，而且手术治疗并不总是被患者接受。骨整合植入物已被证明可以提高稳定性、恢复骨感觉并延长假体使用时间。拇指截肢的残端大小不一：标准尺寸的植入物不能满足每个患者的特异性，而患者匹配的解决方案可以通过植入物的几何特征满足外科医生的要求。本文介绍的固定装置是第一个用于治疗拇指截肢患者的增材制造的患者匹配骨整合植入物。本研究旨在验证和验证用于评估所提出的固定装置机械强度的预测有限元模型 (FEM)。结果表明，FEM 可以正确评估患者匹配装置的机械强度。在不同的芯径下计算出最小强度要求：通过实验验证了 FEM。安全系数为 1.5。最后，通过在 Sawbones 中的插入测试和轴向拔出力评估对原型的性能进行了考虑。正在进行评估整个手术过程和生产过程的尸体测试。
