Ergonomic safety of surgical techniques and standing positions associated with laparoscopic cholecystectomy

Laparoscopic cholecystectomy (LC), a procedure in which, using either a one-handed or two-handed technique, a surgeon removes a symptomatic gallbladder in a minimally invasive manner, is commonly - due to its relatively high safety level - the initial procedure that a resident will perform. Investigation of the ergonomics associated with LC one-handed and two-handed techniques is one goal of this study. Identification of which of two standing positions (between legs or at side) used during LC is the more ergonomically favorable is the other. Knowledge gained from our research in these issues is intended to be applicable both to surgical training and the operating room environment. Eight right-handed laparoscopic surgeons with varying levels of surgical skills were recruited for this study. Each performed LC a total of four times on a virtual reality (VR) simulator with each performance incorporating one of the following conditions: either the one-handed or two-handed surgical technique or the position of standing between the patient's legs or at the patient's side. Each trial was also divided into two phases: 1) dissection and clipping and 2) gall bladder removal. During the performance of LC, physical ergonomic data were collected though surface electrode electromyography (EMG) and two force plates. Additionally NASA-Task Load Index (TLX) and secondary time estimation were used for cognitive ergonomic assessment. Standing at the side produced a significantly higher weight-loading ratio (WLR) than standing between the legs. Comparison bstween techniques indicated that the two-handed technique caused higher WLR. Significant phase effect equated increased WLR with phase 2 gall bladder removal. No statistical interactions among technique, standing position, and phase were significant. Analysis of NASA-TLX showed that global workload, influenced mainly by significant physical workload and effort scales, was higher with the side-standing position and the two-handed technique. The results from time estimation analysis, although statistically marginal, demonstrated that the one-handed technique is more mentally demanding. Our study demonstrated that due to lower physical as well as mental workload, the two-handed technique performed with the surgeon positioned between the patient's legs is the most ergonomically favorable combination. Additionally, it was demonstrated that the pedal for cautery operation requires ergonomic improvement. These specific findings encourage us to continue research into what proof ergonomics can provide regarding what constitutes the most efficacious approaches to surgical procedures and to optimizing patient safety and the surgical environment.