Introduction

Early mobilization after surgery reduces complications and is associated with improved survival, decreased length of hospitalization, and improved psychological well-being [1]. However, current methods for evaluating the mobility and outcomes of spine surgery patients are limited and rely on patient-reported outcome measures (PROMs) that are subjective and may be influenced by psychiatric comorbidities and chronic pain. 

There are numerous commercially available wearable activity monitors, including the Apple Watch, that allow for real-time tracking of objective that may allow patients and surgeons to better monitor post-operative mobility and outcomes.  

Objectives:

(1) To determine feasibility of wearing the Apple Watch before/after spine surgery to assist with surgical recovery; (2) To determine whether objective patient metrics correlate with PROMs before/after spine surgery; (3) To evaluate whether spine surgery improves objective activity measures tracked by the Apple Watch; and (4) To investigate whether patients are more satisfied with their care and have a better understanding of their post-operative recovery by using the Apple Watch.

Methods

Eligibility: Adult patients undergoing elective spine surgery at Stanford Hospital. Patients randomized 1:1 to intervention vs control group. Intervention patients receive Apple Watch, download study-specific HIPPA-compliant application to collect all health measures from Apple Watch. Visual reports (showing steps, distance, flights, standing time, pain, and PROMs), are provided to intervention patients and surgeons at each follow-up.

All patients complete PROMs (SF-36, EQ-5D, PROMIS, NDI, ODI, VAS Pain) pre-operatively and at 6 weeks, 3 months, 6 months, and 1 year post-operatively. All patients complete study-specific questionnaire regarding satisfaction and understanding of surgical recovery.

Our study is approved by the Stanford IRB and actively enrolling as of Sep 1, 2020. Further details are available at <spinetrak.stanford.edu> and <clinicaltrials.gov/ct2/show/NCT04379921>. Target enrollment is 100 intervention and 100 control patients, which is powered at alpha 0.05 and power 80% to detect a 15% difference in ODI.  

Results

To date, we have enrolled 101 patients (n=50 intervention; n=51 control) in SpineTrak. On average, intervention participants have worn their Apple Watch 91.5% of the days since enrollment and for 14.2 hours (+/- 4.5) per day.

At their 6 week post-operative visit, 71% of patients in the intervention group responded that they were very satisfied with the use of the Apple Watch in their spine care and that seeing their Apple Watch activity tracking data at their post-operative visit was extremely helpful. 83% of their neurosurgeons strongly agreed that the Apple Watch summary helped them understand how their patient was doing post-operatively. 

Discussion

Preliminary results of early participants indicate patients are highly compliant with wearing the Apple Watch, and both patients and surgeons have been satisfied with its use in their spine care. Initial analyses do not show a correlation between subjective PROMs and objective measures after spine surgery. This emphasizes the need for a novel metric that combines objective and subjective measures to better track our patients in real-time after spine surgery.