University of Pittsburgh

Evaluating Effect of Microsoft Hololens on Extraneous Cognitive Load During Simulated Cervical Lateral Mass Screw Placement

Clinical Associate Professor
Friday, November 6, 2020 - 12:30pm - 1:30pm

Authors: Dmitriy Babichenko, Edward G. Andrews, Stephen P. Canton, Eliza Beth Littleton, Ravi Patel, Dukens Labaze, Andrew Mills



The use of augmented reality (AR) is widely accepted as a feasible training, planning, and prototyping tool. Unlike virtual reality (VR), which implies a complete immersion in a virtual world, AR adds digital elements to a live view by using a headset or camera on a smartphone.  The ability to project digital elements into the physical world, combined with the Federal Food and Drug Administration (FDA) approval to use the Microsoft HoloLens in surgical procedures, presents a unique opportunity to develop novel neurosurgical and orthopaedic surgery applications of AR, specifically in spine surgery. Placement of any spinal instrumentation is not free from complication, even with modern image-guidance platforms. The potential of AR in spine surgery lies in its ability to enhance the surgeons operative awareness by allowing them to project CT-generated 3D models of the patient’s own bony anatomy with overlaid pre-planned screw trajectories, thus in theory increasing operative efficiency while reducing operative error. Prior to applying AR in the operative suite, the potential negatives associated with using AR technologies in the operative theater, namely their effect on extraneous cognitive load and on task performance, needs to be addressed. A matched crossover trial design was used in which a combined group of 22 neurosurgery and orthopaedic surgery residents, ranging in their training from the second Post-Graduate Year (PGY-2) to chief resident (PGY-7 for neurosurgery and PGY-5 for orthopedic surgery, respectively. Participants  were asked to place cervical lateral mass screws in a standardized, 3D-printed cervical spine with and without the Microsoft Hololens 1 headset worn. Lateral mass screws were placed bilaterally at C4 to C6, with six cervical lateral mass screws placed by each participant in each trial, totaling 12 total screws placed. Overall time to drill six pilot holes, time for placement of each individual screw, pilot hole proximity to a predetermined entry point as defined by the Magerl method, and presence of medial/lateral breaches were assessed and used as surrogate measures of mental taxation. The SURG-TLX questionnaire, a validated measure of extraneous cognitive load, was also used to compare cognitive strain of the task with and without the Hololens 1.

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