Role of psychosocial factors on the effect of physical activity on physical function in patients after lumbar spine surgery

Hiral Master,Clinton J Devin,Jacquelyn S Pennings,Brian J Neuman,Rogelio A Coronado,Stephen T Wegener,Richard L Skolasky,Joseph S Cheng,Christine M Haug,Renan Castillo,Oran S Aaronson,Kristin R Archer,Lee H Riley

doi:10.1186/s12891-021-04622-w

Abstract

BackgroundThe purpose of this study was to investigate the longitudinal postoperative relationship between physical activity, psychosocial factors, and physical function in patients undergoing lumbar spine surgery.MethodsWe enrolled 248 participants undergoing surgery for a degenerative lumbar spine condition. Physical activity was measured using a triaxial accelerometer (Actigraph GT3X) at 6-weeks (6wk), 6-months (6M), 12-months (12M) and 24-months (24M) following spine surgery. Physical function (computerized adaptive test domain version of Patient-Reported Outcomes Measurement Information System) and psychosocial factors (pain self-efficacy, depression and fear of movement) were assessed at preoperative visit and 6wk, 6M, 12M and 24M after surgery. Structural equation modeling (SEM) techniques were utilized to analyze data, and results are represented as standardized regression weights (SRW). Overall SRW were computed across five imputed datasets to account for missing data. The mediation effect of each psychosocial factor on the effect of physical activity on physical function were computed [(SRW for effect of activity on psychosocial factor X SRW for effect of psychosocial factor on function) ÷ SRW for effect of activity on function]. Each SEM model was tested for model fit by assessing established fit indexes.ResultsThe overall effect of steps per day on physical function (SRW ranged from 0.08 to 0.19, p<0.05) was stronger compared to the overall effect of physical function on steps per day (SRW ranged from non-existent to 0.14, p<0.01 to 0.3). The effect of steps per day on physical function and function on steps per day remained consistent after accounting for psychosocial factors in each of the mediation models. Depression and fear of movement at 6M mediated 3.4% and 5.4% of the effect of steps per day at 6wk on physical function at 12M, respectively. Pain self-efficacy was not a statistically significant mediator.ConclusionsThe findings of this study suggest that the relationship between physical activity and physical function is stronger than the relationship of function to activity. However, future research is needed to examine whether promoting physical activity during the early postoperative period may result in improvement of long-term physical function. Since depression and fear of movement had a very small mediating effect, additional work is needed to investigate other potential mediating factors such as pain catastrophizing, resilience and exercise self-efficacy.

Highlights

Over the past two decades, the rate of spine surgery for lumbar degenerative conditions has doubled in the United States [1, 2] and is associated with high hospital costs, i.e., over $10 billion in 2015 [3]
The findings of this study suggest that the relationship between physical activity and physical function is stronger than the relationship of function to activity
Future research is needed to examine whether promoting physical activity during the early postoperative period may result in improvement of long-term physical function

Summary

Introduction

Over the past two decades, the rate of spine surgery for lumbar degenerative conditions has doubled in the United States [1, 2] and is associated with high hospital costs, i.e., over $10 billion in 2015 [3]. Engaging in physical activity is related to better physical functioning in older adults with and without pain [10,11,12,13]. Little is known about the longitudinal relationship between physical activity and physical function in patients after lumbar spine surgery. Some research suggests that limited physical functioning may impair an individual’s ability to participate in physical activity [14, 15]. A better understanding of the directional relationship between physical activity and physical function will provide insights on the early postoperative treatment strategies needed to maximize patients’ long-term recovery trajectory. The purpose of this study was to investigate the longitudinal postoperative relationship between physical activity, psychosocial factors, and physical function in patients undergoing lumbar spine surgery

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