Peri-Operative Patient Mobility in Spine Surgery Patients Varies with Socioeconomic Status

Introduction: The relationship between socioeconomic status and post-operative outcomes has been extensively studied; however, the association between socioeconomic status and patient activity levels before and after spine surgery remains unexplored. By harnessing activity data collected on patient smartphones, surgeons can directly measure patients' physical mobility, enabling a deeper understanding of how economic status, demographic factors, and neurosurgical intervention influence functional health.

Methods: A retrospective study involving 49 patients who underwent spine surgery between 2017 and 2021 was conducted (25 fusions, 24 decompressions). Relying on the zip code of a patient’s primary address, we determined the Area Deprivation Index (ADI) – an independently validated composite measure of socioeconomic disadvantage. Daily steps taken by these patients were remotely collected from patient smartphones using a mobile application across a one-year peri-operative period and statistically normalized to enable inter-patient comparison. Multivariate regression was performed to identify relationships between ADI and patient mobility while controlling for confounders including age and obesity.

Results: Pre-operatively, a direct positive association existed between a patient’s ADI and the number of days where patients had physical activity levels below their individual baseline, defined as the patient’s overall average activity (p=0.037). Specifically, the pre-operative activity of patients living in neighborhoods with ADIs in the bottom 80% was significantly greater than similar patients living in the top 20% of neighborhoods (p=0.018). Post-operatively, the aggregate of patients in the top 20% of neighborhoods returned to baseline faster, at day 56, while those in the bottom 80% returned to baseline at day 108, although this difference was not statistically significant (p=0.864).

Conclusion : Our study demonstrates that individuals in the bottom 80% of neighborhoods were more active before surgery than those in the top 20%, though these differences in mobility cease after surgery. Following surgical intervention, the relatively faster recovery of patients living in wealthier neighborhoods may be due to greater healthcare usage and higher levels of resource utilization, factors we haven’t yet assessed. Further study is needed to qualify potential causal factors behind these observed associations, as well as increase the geographic and demographic diversity of our patient sample.