Which causes more ergonomic stress: laparoscopic or open surgery?

Robert Wang, Zhe Liang, Ahmed M Zihni, MD, MPH, Shuddhadeb Ray, MD, Michael M Awad, MD, PhD. Washington University School of Medicine

INTRODUCTION: As the number of procedures performed laparoscopically has increased dramatically over the last few decades, there is an increasing awareness of the unique ergonomic challenges experienced by the laparoscopic surgeon. Compared to similar open surgeries, laparoscopic procedures are limited by the fulcrum effect, the general lack of articulating instruments, and the adoption of a less mobile posture. On the other hand, the use of laparoscopy allows the surgeon to operate in an upright position without having to lean over the site of incision. Subjective studies of surgeons who perform laparoscopy report a near universal incidence of chronic musculoskeletal pain and injury. To date, the ergonomic stress of laparoscopy compared to open surgery has not been objectively measured. The purpose of this study is to quantify and compare the ergonomic stress experienced by a surgeon while performing open versus laparoscopic portions of a procedure. We hypothesize that a surgeon will experience greater ergonomic strain when performing laparoscopic surgery than when performing open surgery.

METHODS AND PROCEDURES: We designed a prospective study to measure upper body muscle activation during the laparoscopic and open portions of sigmoid colectomies in a single surgeon. A sample of five cases were recorded over a two-month time span (June to July 2014). Each case contained significant portions of laparoscopic and open surgery (average duration of laparoscopic surgery was 89.7 min; average duration of open surgery was 84.1 min). Using a wireless electromyography (EMG) system, we obtained whole-case EMG tracings from the subject’s left and right biceps, triceps, deltoid, and trapezius muscles. After normalization to a maximum voltage of contraction (MVC), these EMG tracings were used to calculate average muscle activation during the open and laparoscopic segments of each procedure. Paired Student’s T-test was used to compare the average muscle activation between the two groups (*p <0.05 considered statistically significant).

RESULTS: Significant reductions of mean muscle activation in laparoscopic compared to open procedures were noted for the left triceps (34.7%), left deltoid (45.8%), left trapezius (53.6%), right triceps (37.3%) and right trapezius (54.0%). There were no statistically significant changes of mean muscle activations in the left biceps, right biceps and right deltoid between open and laparoscopic portions of the procedures.

imageCONCLUSION: Contrary to our hypothesis, the laparoscopic approach provided ergonomic benefit in several upper body muscle groups compared to the open approach. This may be due to the greater reach of laparoscopic instruments and camera in the lower abdomen/pelvis. Patient body habitus may also have less of an effect in the laparoscopic compared to open approach. Performing the study in a single subject allowed for control of inter-surgeon variability. Analysis of paired data of open and laparoscopic portions within individual procedures helped control for variability in patient factors (e.g., body habitus, degree of difficulty). Future studies with multiple subjects and different types of procedures are planned to further investigate these findings.

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