An Additional Dimension in Endoscopic Ear Surgery: A Randomized Comparison of 3D vs. 2D Endoscopy Using Eye Tracking and Assessment of Cognitive Load

By June 7, 2019

Introduction: Endoscopic ear surgery (EES) is an emerging technique to treat middle ear pathologies. However, the interventions are performed in 2-dimensional (2D) endoscopic views, which do not provide depth perception. Recent technical developments allow the application of three-dimensional (3D) endoscopy in EES. We aim to investigate under standardized conditions the usability, advantages and disadvantages of 3D vs. 2D endoscopy in EES.

Methods: Sixteen residents and consultants of the Department of Otorhinolaryngology, Head & Neck Surgery, Inselspital Bern, Switzerland were participated in this study. Each participant performed selected steps of a tympanoplasty type I and stapedotomy in 2D as well as in 3D in a cadaveric model (counterbalanced by latin square). Time, attempts and accidental damages during the dissections were compared between both techniques. Eye-tracking was performed throughout the interventions. Cognitive load and subjective feedback was measured by standardized questionnaires.

Results: Assessment of surgical time revealed shorter operating times for inexperienced surgeons using the 3D technique. Most surgeons preferred the 3D technique, even though a higher incidence of eye strain was observed. Eye movement assessment revealed higher fixation duration for consultants in 2D as compared to 3D and to residents. Cognitive load was similar for both techniques.

Discussion: Three-dimensional endoscopy is suitable for EES offering shorter surgical times and subjective benefits, especially for young surgeons whose mental model of the intervention has yet to be consolidated. Therefore, the application of 3D endoscopy in clinical routine and for educational purposes appears feasible and beneficial.