3D vs. 4K Display System - Influence of "State-of-the-art"-Display Technique On Surgical Performance (IDOSP-Study) in minimally invasive surgery: protocol for a randomized cross-over trial.

Background: Three-dimensional (3D) stereoscopic vision is crucial to perform any kind of manual task. The reduction from real life 3D to virtual two-dimensional (2D) sight is a major challenge in minimally invasive surgery (MIS). A 3D display technique has been shown to reduce operation time and mistakes and to improve the learning curve. Therefore, the use of a3D display technique seems to optimize surgical performance for novice and experienced surgeons. Inspired by consumer electronics, a 4K display technique was recently introduced to MIS. Due to its high resolution and zoom effect, surgeons should benefit from it. The aim of this study is to evaluate if "state-of-the-art" 3D- vs. 4K-display techniques could influence surgical performance.

Methods: A randomized, cross-over, single-institution, single-blinded trial is designed. It compares the primary outcome parameter "surgical performance", represented by "performance time "and "number of mistakes", using a passive polarizing 3D and a 4K display system (two arms) to perform different tasks in a minimally invasive/laparoscopic training parkour. Secondary outcome parameters are the mental stress load (National Aeronautics and Space Administration (NASA) Task Load Index) and the learning curve. Unexperienced novices (medical students), non-board-certified, and board-certified abdominal surgeons participate in the trial (i.e., level of experience, 3 strata). The parkour consists of seven tasks (for novices, five tasks), which will be repeated three times. The 1st run of the parkour will be performed with the randomized display system, the 2nd run with the other one. After each run, the mental stress load is measured. After completion of the parkour, all participants are evaluated by an ophthalmologist for visual acuity and stereoscopic vision with five tests. Assuming a correlation of 0.5 between measurements per subject, a sample size of 36 per stratum is required to detect a standardized effect of 0.5 (including an additional 5% for a non-parametric approach) with a power of 80% at a two-sided type I error of 5%. Thus, altogether 108 subjects need to be enrolled.

Discussion: Complex surgical procedures are performed in a minimally invasive/laparoscopic technique. This study should provide some evidence to decide which display technique a surgeon could choose to optimize his performance.

Trial Registration: ClinicalTrials.gov, NCT03445429 . Registered on 7 February 2018.