Comparison of 3- vs 2-Dimensional Endoscopy Using Eye Tracking and Assessment of Cognitive Load Among Surgeons Performing Endoscopic Ear Surgery

Anschütz, Lukas; Niederhauser, Laura; Wimmer, Wilhelm; Yacoub, Abraam; Weibel, David; Mast, Fred W.; Caversaccio, Marco (2019). Comparison of 3- vs 2-Dimensional Endoscopy Using Eye Tracking and Assessment of Cognitive Load Among Surgeons Performing Endoscopic Ear Surgery. JAMA otolaryngology - head & neck surgery, 145(9), pp. 838-845. American Medical Association 10.1001/jamaoto.2019.1765

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Importance: Endoscopic ear surgery (EES) is an emerging technique to treat middle ear diseases; however, the interventions are performed in 2-dimensional (2D) endoscopic views, which do not provide depth perception. Recent technical developments now allow the application of 3-dimensional (3D) endoscopy in EES.

Objective: To investigate the usability, advantages, and disadvantages of 3D vs 2D endoscopy in EES under standardized conditions.

Design, Setting, and Participants: This cohort study conducted at a tertiary academic medical center in Bern, Switzerland, included 16 residents and consultants of the Department of Otorhinolaryngology, Head & Neck Surgery, Inselspital, Bern.

Interventions: Each participant performed selected steps of a type I tympanoplasty and stapedotomy in 3D and 2D views in a cadaveric model using a randomized, Latin-square crossover design.

Main Outcomes and Measures: Time taken to perform the EES, number of attempts, and accidental damage during the dissections were compared between 3D and 2D endoscopy. Eye tracking was performed throughout the interventions. Cognitive load and subjective feedback were measured by standardized questionnaires.

Results: Of the 16 surgeons included in the study (11 inexperienced residents; 5 experienced consultants), 8 were women (50%); mean age was 36 years (range, 27-57 years). Assessment of surgical time revealed similar operating times for both techniques (181 seconds in 2D vs 174 seconds in 3D). A total of 64 surgical interventions were performed. Most surgeons preferred the 3D technique (10 for 3D vs 6 for 2D), even though a higher incidence of eye strain, measured on a 7-point Likert scale, was observed (3D, 2.19 points vs 2D, 1.44 points; mean difference , 0.74; 95% CI, 0.29-1.20; r = 0.67). Eye movement assessment revealed a higher duration of fixation for consultants in 2D (0.79 seconds) compared with 3D endoscopy (0.54 seconds), indicating a less-efficient application of previously acquired experiences using the new technique. Residents (mean [SD], 49.02 [16.4]) had a significantly higher workload than consultants (mean [SD], 27.21 [12.20]), independent of the used technique or task.

Conclusions and Relevance: Three-dimensional endoscopy is suitable for EES, especially for inexperienced surgeons whose mental model of the intervention has yet to be consolidated. The application of 3D endoscopy in clinical routines and for educational purposes may be feasible and beneficial.

Item Type:

Journal Article (Original Article)


04 Faculty of Medicine > Department of Head Organs and Neurology (DKNS) > Clinic of Ear, Nose and Throat Disorders (ENT)
10 Strategic Research Centers > ARTORG Center for Biomedical Engineering Research > ARTORG Center - Hearing Research Laboratory
07 Faculty of Human Sciences > Institute of Psychology > Cognitive Psychology, Perception and Methodology

UniBE Contributor:

Anschütz, Lukas Peter, Niederhauser, Laura, Wimmer, Wilhelm, Yacoub, Abraam, Weibel, David, Mast, Fred, Caversaccio, Marco


600 Technology > 610 Medicine & health
100 Philosophy > 150 Psychology




American Medical Association




Wilhelm Wimmer

Date Deposited:

07 Aug 2019 15:21

Last Modified:

05 Dec 2022 15:30

Publisher DOI:


PubMed ID:





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