146 Consistency of Spatiotemporal Parameters Obtained From Smartphone-based 3D Motion Capture With Standard Clinically Graded Gait Analysis

INTRODUCTION: Gait analysis and severity grading in spine surgery are mostly subjective. Objective measurement of gait by spatiotemporal parameters using 3D Motion Capture technology is a newer emerging technique, yet to be validated for use in spine surgery patients. Correlating spatiotemporal parameters with standard clinical grading can be the initial step to set the tone for validation and assessing application in spine surgery. METHODS: A total of 281 videos of walking and tandem gait of 26 Cervical Myelopathy patients presenting to 3 Barnes Jewish Hospital locations were recorded at multiple timepoints – preoperative and postoperative at 6 weeks, 3 months and 6 months. Spatiotemporal parameters were obtained from 3D motion captured video data processed with PosePipe. 5 research team members graded all the videos out of 10 based on symmetry, fluidity, foot strike, step length, upper body movement, cadence, limping, Foot/toe dragging and assistive devices. mJOA scores were recorded for each patient. Statistical analysis was performed using Python 3.11.5 and R 4.4.0; Spearman’s r Correlation Coefficient was used for determining correlation. RESULTS: The average rating by all 5 graders was around 5 to 6 out of 10 for all 281 videos. All 4 spatiotemporal parameters i.e. cadence, pelvic velocity, double support percentage and step-length were statistically significantly associated with 3 out of 5 graders’ ratings. Cadence and pelvic velocity were statistically significantly associated with mJOA scores of patients. CONCLUSIONS: Spatiotemporal parameters offer objective assessment of gait which can be used to supplement standard clinical assessment. Further analysis with larger data sets can aid in validating and concurrently fine-tuning 3D motion capture technology for application in spine surgery.