Using Smartphone-Based Accelerometer Data to Objectively Assess Outcomes in Spine Surgery

BACKGROUND: In order to deliver optimal patient care, spine surgeons must integrate technological changes to arrive at novel measures of functional outcomes. Historically, subjective patient-reported outcome (PRO) surveys have been used to determine the relative benefit of surgical treatments. Using smartphone-based accelerometers, surgeons now have the ability to arrive at objective outcome metrics. OBJECTIVE: To use Apple Health (Apple Inc, Cupertino, California) data to approximate physical activity levels before and after spinal fusion as an objective outcome measurement. METHODS: Personal activity data were acquired retrospectively from the cellphones of consenting patients. These data were used to measure changes in activity level (daily steps, flights climbed, and distance traveled) before and after patients underwent spine surgery at a single institution by a single surgeon. After data collection, we investigated the demographic information and daily physical activity pre-and postoperatively of participating patients. RESULTS: Twenty-three patients were included in the study. On average, patients first exceeded their daily 1-yr average distancewalked, flights climbed, and steps taken at 10.3 +/- 14, 7.6 +/- 21.1, and 8 +/- 9.9wk, respectively. Mean flights climbed, distance traveled, and steps taken decreased significantly from 6mo prior to surgery to 2 wk postoperatively. Distance traveled and steps taken significantly increased from 6 mo prior to surgery to 7 to 12 mo postoperatively. CONCLUSION: We demonstrated a valuable supplement to traditional PROs by using smartphone-based activity data. This methodology yields a rich data set that has the potential to augment our understanding of patient recovery.