Physical Activity as a Predictor of Chronic Pain following Pediatric Spinal Surgery

Objectives:(1) Characterize objective physical activity patterns via actigraphy over 4 months postspinal fusion surgery, and (2) examine associations between activity patterns at 2-week and chronic postsurgical pain (CPSP) status at 4 months.Materials and Methods:Data from 109 youth (10 to 18 y) who underwent spinal fusion surgery at a children's hospital in the Northwestern United States were analyzed. Youth completed questionnaires and actigraphic assessment of physical activity presurgery, and 2 weeks and 4 months postsurgery.Results:Eighteen percent of youth developed CPSP at 4 months. Presurgery physical activity was similar for youth with and without CPSP. At 2 weeks postsurgery, daily activity levels were lower for youth who developed CPSP as compared with those who did not, including lower mean activity (168 vs. 212 counts/min, P=0.01), fewer activity bouts (n=1.7 vs. 2.6, P=0.02), and shorter bout duration (27 vs. 40 min, P=0.02). Differences in activity were maintained at 4 months such that youth with CPSP had lower mean activity (284 vs. 334 counts/min, P=0.03), as well as greater proportion time spent sedentary and lower proportion time in light activity than youth without CPSP. In adjusted models examining 2-week actigraphy as a predictor of 4-month pain status, mean activity (odds ratio=0.99, P=0.04) and number of activity bouts (odds ratio=0.79, P=0.02) were associated with subsequent CPSP status over and above 2-week pain intensity.Discussion:Lower activity engagement during the initial weeks following spinal fusion surgery was associated with development of CPSP, suggesting early physical activity limitations as a risk factor for CPSP in youth. Understanding recovery patterns is critical for identifying those at risk for chronic pain and implementing early interventions.