Ergonomic assessment of the first assistant during robot-assisted surgery.

The use of the da Vinci robot in minimal invasive surgery comes with numerous advantages. Recent papers describe improvements in the ergonomic environment and benefits for the surgeon's posture in the console. Ergonomics for first assistants or scrub nurses at the OR table during robot-assisted procedures, however, have gained minor attention. The aim of this study, therefore, is to analyse the ergonomic environment specifically for first assistants during robot-assisted surgery. Three techniques were used to evaluate body posture and ergonomics during three discriminated actions. First of all, a questionnaire was conducted. Second, sagittal and dorsal photographs of all first assistants were shot. From these photographs, joint angles of the trunk, neck, shoulder, elbow, pelvic girdle and spine were calculated and rapid upper limb assessment (RULA) scores were determined. In addition, intra-observer variability was assessed to determine the robustness of the results. Lastly, the number of obstructions during the surgery was registered by an observer present at the operation theatre. The questionnaires displayed that 73% of the first assistants were in uncomfortable working positions for longer periods of time. Twenty percent of the participants even report pain or visible bruising due to hinderance of the robot arm. Furthermore, an average of 2.8 obstructions per surgical procedure was registered, mainly affecting the lower arm (60%). The photographs demonstrated that all joint angles, except for the elbow joint, are potentially harmful when assisting during robot-assisted surgery. RULA scores revealed high-risk ergonomic risk scores for all measured actions. Tissue traction was recognized as the action with the highest physical workload. During robot-assisted surgery, first assistants experience non-ergonomic trunk, neck and shoulder angles. These recordings are supported by posture analysis. Tissue traction is reported as the most intensive action by the nurses. Tacking, however, can lead to the most unfavourable RULA score. The surgeon's awareness of the position of the robot arms could reduce the number of obstructive moments for the first assistant. Lowering the number of instrument replacements is plausible to lead to better ergonomic postures for first assistant.