Hsu Justin L, Korndorffer James R, Brown Kimberly M
Department of Surgery, University of Texas Medical Branch, Galveston, Texas.
Department of Surgery, Tulane University School of Medicine, New Orleans, Los Angeles.
J Surg Res. 2015 Aug;197(2):231-5. doi: 10.1016/j.jss.2015.02.068. Epub 2015 Mar 6.
Surgical residents develop technical skills at variable rates, often based on random chance of cases encountered. One such skill is tying secure knots without exerting excessive force. This study describes the design of a simulator using a force sensor to measure instantaneous forces exerted on a blood vessel analog during vessel ligation and the development of expert-derived performance goals.
Vessel ligations were performed on Silastic tubing at an offset from a Vernier Force Sensor. Nine experts (surgical faculty and senior residents) and 10 novices (junior residents) were recruited to each perform 10 vessel ligations (two square knots each) with two-handed and one-handed techniques. Internal consistency for the series of vessel ligations was tested with Cronbach alpha. Maximum forces exerted by novices and experts were compared using Student t-test.
Internal consistency across the 10 ligations on the simulator was excellent (Cronbach alpha = 0.91). The expert group on average exerted a significantly lower maximum force when compared with novices while performing two-handed (0.76 ± 0.39 N versus 1.12 ± 0.49 N, P < 0.01) and one-handed (0.84 ± 0.32 N versus 1.36 ± 0.44 N, P < 0.01) vessel ligations.
Although the expert group performed vessel ligations with significantly lower peak force than the novice group, there were novices who performed at the expert level. This is consistent with the conceptual framework of milestones and suggests that the skill of gentle knot-tying can be measured and develops at different chronologic levels of training in different individuals. This simulator can be used as part of a deliberate practice curriculum with instantaneous visual feedback.
外科住院医师掌握技术技能的速度各不相同，这通常取决于所遇到病例的随机机会。其中一项技能是在不施加过大力量的情况下系紧牢固的结。本研究描述了一种模拟器的设计，该模拟器使用力传感器来测量血管结扎过程中施加在血管模拟物上的瞬时力，并制定了专家得出的性能目标。
在与游标力传感器有一定偏移的硅橡胶管上进行血管结扎。招募了9名专家（外科教员和高级住院医师）和10名新手（初级住院医师），每人用双手和单手技术各进行10次血管结扎（每次两个方结）。使用Cronbach α检验血管结扎系列的内部一致性。使用学生t检验比较新手和专家施加的最大力。
模拟器上10次结扎的内部一致性极佳（Cronbach α = 0.91）。与新手相比，专家组在进行双手（0.76±0.39 N对1.12±0.49 N，P < 0.01）和单手（0.84±0.32 N对1.36±0.44 N，P < 0.01）血管结扎时平均施加的最大力显著更低。
尽管专家组进行血管结扎时的峰值力明显低于新手组，但也有新手达到了专家水平。这与里程碑的概念框架一致，表明轻柔打结的技能可以被测量，并且在不同个体的不同训练时间水平上发展。该模拟器可作为具有即时视觉反馈的刻意练习课程的一部分使用。
