Ergonomics-based Positioning of the Operating Handle of Surgical Microscopes

Handling surgical microscopes with one hand requires force, especially when gripping the operating handle (OH) to swing the optic axis toward the surgeon and when moving it laterally or medially. These physical issues may be attributable to the non-ergonomic handling of the OH. To optimize the ease of OH handling, we applied ergonomic criteria to the positioning of the OH, i.e. holding the OH at as little ulnar deviation as possible and at abduction to strengthen the grip and ease arm rotation. Of eight male surgeons holding the OH of a mechanically counterbalanced surgical microscope, the OPMI Neuro/NC4 (Carl Zeiss AG), in ergonomics-based positions, six experienced reduced fatigue in the upper extremity. All reported that their hold on the microscope was firm when it unexpectedly became unbalanced. Ergonomics-based OH positioning, i.e. placing the involved muscles in the optimal length-tension relationship, may generate sufficient force for moving the microscope efficiently and reduce arm fatigue.