A passive exoskeleton to prevent low back and neck overload in surgeons

Promotion C. Zhang

Surgeons are at high risk for developing musculoskeletal symptoms (MSS) at the neck and back due to prolonged work in unfavorable positions and repetitive movements. The aim was to reduce the biomechanical load on surgeons using exoskeleton technology to prevent MSS.

In this thesis of Ce Zhang two main challenges were addressed: (1) measuring the biomechanical load of surgeons, and (2) developing and evaluating the exoskeleton. To measure the biomechanical load in the operating room, we proposed inertial measurement unit (IMU) and markerless methods, with the IMU method showing excellent agreement with the gold standard (optical electrical system).

Following, the IMU method was used to analyze the biomechanics of surgical trainees during open surgery. This revealed neck flexion angles between 10 and 40 degrees for 71.6% of the time and lumbar flexion between 10 and 30 degrees for 68.9% of the time. These findings guided the design of a novel passive exoskeleton prototype supporting the neck and trunk using a three-point bending system with carbon fiber beams and an auto-switch mechanism for walking, allowing the required range of motion.

Finally, a biomechanical evaluation study with ten participants performing simulated surgery tasks showed significant reductions in trunk and neck extensor muscle activity (up to 22% and 21%, respectively) and spinal compression forces (19% reduction in L5-S1 spine compression and 26% decrease in neck joint compression) during tasks. Despite some limitations, such as reduced lumbar axial range of motion and overcompensation during large neck flexion angles, the exoskeleton effectively reduces muscle activity and may help prevent MSS in surgeons.