Outcomes of prior work.

BackgroundHealthcare simulators have been demonstrated to be a valuable resource for training several technical and nontechnical skills. A gap in the fidelity of tissues has been acknowledged as a barrier to application for current simulators; especially for interventional procedures. Inaccurate or unrealistic mechanical response of a simulated tissue to a given surgical tool motion may result in negative training transfer and/or prevents the “suspension of disbelief” necessary for a trainee to engage in the activity. Thus, where it is relevant to training outcomes, there should be an effort to create healthcare simulators with simulated tissue mechanical responses that match or represent those of biological tissues. Historically, this data is most often gathered from preserved (post mortem) tissue; however, there is a concern that the mechanical properties of preserved tissue, that lacks blood flow, may lack adequate accuracy to provide the necessary training efficacy of simulators.Methods and findingsThis work explores the effect of the “state” of the tissue testing status on liver and peritoneal tissue by using a customized handheld grasper to measure the mechanical responses of representative porcine (Sus domesticus) tissues in n = 5 animals across five test conditions: in vivo, post mortem (in-situ), ex vivo (immediately removed from fresh porcine cadaver), post-refrigeration, and post-freeze-thaw cycle spanning up to 72 hours after death. No statistically significant difference was observed in the mechanical responses due to grasping between in vivo and post-freeze conditions for porcine liver and peritoneum tissue samples (p = 0.05 for derived stiffness at grasping force values F = 5N and 6.5N). Furthermore, variance between in vivo and post-freeze conditions within each animal, was comparable to the variance of the in vivo condition between animals.ConclusionsResults of this study further validate the use of preserved tissue in the design of medical simulators via observing tissue mechanical responses of post-freeze tissue comparable to in vivo tissue. Therefore, the use of thawed preserved tissue for the further study and emulation of mechanical perturbation of the liver and peritoneum can be considered. Further work in this area should investigate these trends further, particularly in regard to other tissues and the potential effects varying preservation methods may yield.# 背景 医疗模拟器已被证实是培养多项技术与非技术技能的宝贵资源。当前模拟器存在组织逼真度不足的缺陷，这已被认定为其应用的一大障碍，尤其针对介入手术操作。模拟组织对手术器械运动的力学响应若不准确或不真实，可能引发负面训练迁移，或妨碍受训者沉浸于训练所需的置信悬置（suspension of disbelief）。因此，在对训练效果存在影响的场景中，应着力开发能够模拟与生物组织匹配或一致的力学响应的医疗模拟器。过往此类数据多采集自保存（死后，post mortem）的组织，但学界存在顾虑：缺乏血液灌注的保存组织，其力学性能可能无法满足模拟器所需的训练效能要求。 # 方法与研究结果 本研究采用定制化手持抓取器，针对5头实验家猪（Sus domesticus）的代表性组织，在五种测试条件下测量其力学响应，以探究组织测试状态对肝脏与腹膜组织的影响：活体（in vivo）、死后原位（post mortem (in-situ)）、离体（刚从新鲜家猪尸体取下，ex vivo (immediately removed from fresh porcine cadaver)）、冷藏后，以及死后长达72小时的冻融循环后（post-freeze-thaw cycle spanning up to 72 hours after death）。结果显示，对于家猪肝脏与腹膜组织样本，当抓取力为5N与6.5N时推导得到的刚度（p=0.05），活体与冻后条件下的力学响应未观察到统计学显著差异。此外，每头动物个体内活体与冻后条件间的方差，与不同动物个体间活体条件的方差基本相当。 # 结论 本研究结果进一步验证了保存组织在医疗模拟器设计中的应用价值：通过观测到冻后组织的力学响应与活体组织相近。因此，可考虑采用解冻后的保存组织开展肝脏与腹膜力学扰动模拟的后续研究与实验。该领域的后续工作应进一步探究此类趋势，尤其是针对其他组织类型，以及不同保存方法可能带来的潜在影响。