The ergonomics of laparoscopic surgery: a quantitative study of the time and motion of laparoscopic surgeons in live surgical environments.

Abstract

Laparoscopic surgery presents multiple ergonomic difficulties for the surgeon, requiring awkward body postures and prolonged static muscle loading that increases risk of musculoskeletal strain and injury. This prospective study quantitatively measures the biomechanical movements of surgeons during laparoscopic procedures to determine at-risk movements from prolonged static muscle loading and repetitive motions that may lead to injury. A total of 150 video recordings of 18 surgeons, standing at the patient's left, were captured from three fixed camera positions during live gynecological laparoscopic surgery. Postoperative processing quantified surgeon movements at the neck, shoulders and elbows using computer software to measure extreme joint angles and time spent within defined joint angle ranges. Surgeons spent a median of 98% (range 77-100%) of surgical time with their neck rotated at 21° (range 0°-52°). The non-dominant arm was subjected to more extreme positions for significantly longer periods of time compared to the dominant, with shoulder flexion at 45°-90° for 35 vs. 0% (p<0.001) and elbow flexion at >120° for 31 vs. 0% (p<0.001) of total surgical time. Procedures involving power morcellation required significantly greater number of instrument insertion/removals-119 (range 56-182) compared with 12 (range 2-122) when morcellation was not used (p<0.001). Shorter surgeons maintained significantly greater degrees of neck rotation when viewing the monitor (p<0.003) and surgeons with shorter arm lengths spent longer in extreme positions with their non-dominant shoulder at >90° (p=0.04) and elbow at >120° (p<0.001) compared with taller surgeons. No significant correlations were found between BMI or surgical experience and more extreme joint positions. Four primary areas have been identified where surgeons are consistently demonstrating movements that increase their risk of harm: (1) extended periods of neck rotation; (2) asymmetrical loading between the dominant and non-dominant shoulders; (3) power morcellation and frequent insertions/removals of laparoscopic instruments resulting in repetitions of the most extreme shoulder positions and (4) a negative correlation between height and percentage time spent in more extreme positions.