Department of Obstetrics and Gynecology, The University of Kansas Medical Center, Kansas City, KS.
Department of Mechanical Engineering, The University of Kansas, Lawrence, KS.
Am J Obstet Gynecol. 2023 Sep;229(3):307.e1-307.e9. doi: 10.1016/j.ajog.2023.05.007. Epub 2023 May 16.
"Laparoscopist's thumb," or thenar paresthesia, can result from prolonged or excessive grip force during laparoscopy, as can more general syndromes, such as carpal tunnel syndrome. This is particularly relevant in gynecology, where laparoscopic procedures are standard. Although this method of injury is well known, there is a paucity of data to guide surgeons in selecting more efficient, ergonomic instruments.
This study compared the ratio of applied tissue force and required surgeon input in a sample of common ratcheting laparoscopic graspers in a small-handed surgeon, to provide potential metrics applicable to surgical ergonomics and surgeon instrument choice.
Laparoscopic graspers with varied ratcheting mechanisms and tip shapes were evaluated. Brands included Snowden-Pencer, Covidien, Aesculap, and Ethicon. A Kocher was used as an open instrument comparison. Flexiforce A401 thin-film force sensors were used to measure applied forces. Data were collected and calibrated using an Arduino Uno microcontroller board with Arduino and MATLAB software. Single-handed, complete closure of each device's ratcheting mechanism was performed 3 times. The maximum required input force in Newtons was recorded and averaged. The average output force was measured with a bare sensor and the same sensor between 2 different thicknesses of LifeLike BioTissue.
The most ergonomic ratcheting grasper for a small-handed surgeon was identified by the output ratio: the highest output force relative to the required surgeon input (the most force for the least amount of effort). The Kocher required an average input force of 33.66 N, with its highest output ratio of 3.46 (112 N output). The Covidien Endo Grasp was the most ergonomic, with an output ratio of 0.96 on the bare force sensor (31.4 N output). The Snowden-Pencer Wavy grasper was the least ergonomic, with an output ratio of 0.06 when applied to the bare force sensor (5.9 N output). All graspers except for the Endo Grasp had improving output ratios as tissue thickness and subsequent grasper contact area increased. Input force above that provided by the ratcheting mechanisms did not increase output force in a clinically relevant amount for any of the instruments evaluated.
Laparoscopic graspers vary widely in their ability to provide reliable tissue force without requiring excessive input by the surgeon, and a point of diminishing returns often exists with increased surgeon input over designed ratcheting mechanisms. Output force and output ratio are potential quantitative measures of the efficiency of laparoscopic instruments. Providing users with this type of data could assist in optimizing instrument ergonomics.
“腹腔镜医师拇指”或鱼际感觉异常，可能是由于腹腔镜手术中长时间或过度握持力引起的，也可能是更常见的综合征，如腕管综合征。在妇科中，腹腔镜手术是标准的，这一点尤其相关。尽管这种损伤方法众所周知，但指导外科医生选择更有效、符合人体工程学的仪器的数据却很少。
本研究比较了一组小手掌外科医生中常见的棘轮腹腔镜抓握器的应用组织力与所需外科医生输入力的比值，为外科手术的人体工程学和外科医生仪器选择提供潜在的衡量标准。
评估了具有不同棘轮机构和尖端形状的腹腔镜抓握器。品牌包括 Snowden-Pencer、Covidien、Aesculap 和 Ethicon。 Kocher 用作开放式仪器比较。Flexiforce A401 薄膜力传感器用于测量应用力。使用 Arduino Uno 微控制器板和 Arduino 及 MATLAB 软件收集和校准数据。单手完成每个设备棘轮机构的完全闭合 3 次。记录并平均牛顿的最大所需输入力。使用裸传感器和 LifeLike BioTissue 两种不同厚度之间的相同传感器测量平均输出力。
通过输出比确定了最符合人体工程学的小手掌外科医生棘轮抓握器：相对于所需外科医生输入（最少的努力产生最大的力），输出力最高。Kocher 需要平均输入力 33.66 N，其最高输出比为 3.46（输出 112 N）。Covidien Endo Grasp 在裸力传感器上的输出比最高，为 0.96（输出 31.4 N），是最符合人体工程学的。Snowden-Pencer Wavy 抓握器在应用于裸力传感器时最不符合人体工程学，输出比为 0.06（输出 5.9 N）。除了 Endo Grasp 之外，所有抓握器的输出比都随着组织厚度和随后的抓握器接触面积的增加而增加。对于评估的任何仪器，超过棘轮机构提供的输入力都不会在临床上显著增加输出力。
腹腔镜抓握器在提供可靠的组织力而无需外科医生输入方面差异很大，并且随着外科医生输入超过设计棘轮机构，往往会出现收益递减。输出力和输出比是腹腔镜仪器效率的潜在定量衡量标准。为用户提供此类数据可能有助于优化仪器的人体工程学。
