Fostering Lifestyle Walking After Complex Lumbar Surgery and Longitudinal Improvements in General Function and Lumbar-Specific Disability

Study Design. Cohort study of pooled data from patients enrolled in a behavior randomized trial (RCT) that successfully increased physical activity after complex lumbar surgery. Objective. To assess associations between increased energy expenditure from walking and general functional status and lumbar-specific disability 12 months after enrollment. Background. Many postoperative patients retain preoperative sedentary lifestyles and thus do not obtain general health and spine-related benefits of physical activity. Methods. Three months after complex lumbar surgery (i.e. fusion, ≥3 levels) patients were enrolled in a behavior RCT aimed at increasing physical activity from walking measured by the Paffenbarger Physical Activity and Exercise Index (PAEI) in kcals/week. Data were pooled for this analysis to assess associations between kcals/week at 12 months and change in general functional status (RAND 12-Item Physical Component Summary score, PCS) and lumbar-specific disability (Oswestry Disability Index, ODI). Covariates considered included age, sex, body mass index, back pain, surgical complexity, depressive symptoms, and enrollment PCS, ODI and kcals/week. Results. Among 231 patients (mean age 64, 47% women) enrollment walking was 1361±1294 kcals/week and increased to 1935±1979 kcals/week at 12 months, mean within-patient change 574 kcals/week ( P <.0001). Enrollment PCS score was 37±10 and improved to 44±11 at 12 months, exceeding a clinically important difference (CID). Change in PCS score was associated with kcals/week at 12 months in multivariable analysis controlling for enrollment kcals/week and PCS score (coefficient .002, 95% CI .001-.003, P <.0001). Enrollment ODI score was 34±16 and improved to 27±19 at 12 months, exceeding a CID. Change in ODI score was associated with kcals/week at 12 months in multivariable analysis controlling for enrollment kcals/week and ODI score (coefficient .01, 95% CI 0.002-.005, P <0.0001). Conclusions. Increased postoperative energy expenditure from walking at 12 months was associated with improvement in general functional status and reduced lumbar-specific disability in patients after complex lumbar surgery.