Surgeon's comfort: The ergonomics of a robotic exoscope using a head-mounted display

Abstract

Introduction: Conventional microscopes have certain limitations in terms of posture and ergonomics. Monitor-based exoscopes could solve this problem and thereby lead to less work-related sick leave for surgeons.

Research question: The aim of this study was to assess the ergonomics, usability, and neurosurgeon's comfort of a novel three-dimensional head-mounted display-based exoscope in a standardized setting.

Material & methods: 34 neurosurgeons participated in a workshop on the exoscope, which features a head-mounted display and a head gesture-triggered control panel. After completion of a custom-made 10-step microsurgical exercise, image quality and comfort were assessed using a questionnaire. The participants' posture during the exercise was analyzed using a video motion analysis software.

Results: 34 participants (median neurosurgical experience: 6 years) were included. The median time to complete the exercise was 12 ​min [IqR 9.4, 15.0]. Younger participants (p ​= ​0.005) and those with video game experience (p ​= ​0.03) had a significantly steeper learning curve. The median overall satisfaction was at 80% in general and 82% for image quality. The median upper body as well as the median head coronal displacement from the neutral axis were 0°. Participants with less microsurgical experience showed less head/body displacement during the exercise (p ​= ​0.01).

Discussion and conclusion: Using the microsurgical training tool, we were able to depict a steep learning curve with a sufficient learnability of the most relevant commands. The exoscope excelled in usability, image quality as well as in ergonomic and favorable posture and could thus become an alternative to conventional microscopes due to the potentially elevated surgeons' comfort.

Keywords: Exoscope; Microscope; Microsurgery; Neurosurgery; Robotics; Surgeons' ergonomics.

Fig. 1

Start position of the participant with HMD set up and exercise centered on the working table (A). Operating the robot controlled exoscope with the user interface (B, 1 ​= ​orbit movement, 2 ​= ​magnification, 3 ​= ​translating movement, 4 ​= ​focus).

Fig. 2

Standardized microsurgical test with eyelets shown from different perspectives. Participants were asked to perform the exercise in a standardized fashion for each eyelet (Step 1: Centering of the eyelet, Step 2: Tilting the exoscope until the hole of the eyelet was not visible, Step 3: Threading the 6/0 needle through the hole).

Fig. 3

Workflow diagram showing the position of the exoscope (RS) as well as the different camera positions and the corresponding video angles (a–d).

Fig. 4

Bullseye score. Each eyelet was assessed respectively, thereby creating a score reaching from 10 (minimal centering of each eyelet) to 30 (optimal centering of each eyelet).

Fig. 5

Analysis of body and head posture during the exercise. The reference points were set at the uppermost point of the head, the coronal rotational center of the neck and the right shoulder for head movement. Upper body movement was measured as the angle between the horizontal, the lumbosacral spine as well as the coronal rotational center of the neck.