The impact of pelvic balance, physical activity, and fear-avoidance on the outcome after decompression and instrumented fusion for degenerative lumbar stenosis

Purpose: To evaluate the impact of pelvic balance, physical activity, and fear-avoidance in a cohort of patients undergoing decompression and instrumented fusion for degenerative lumbar stenosis. Materials and methods: This study includes consecutive patients undergoing decompression and instrumented fusion for degenerative lumbar stenosis by one main surgeon from January 2014 to January 2015. Patients were interviewed by a psychologist and underwent standing whole spine X-ray. Lumbar and pelvic parameters (PI, SS, PT, iPT, LL) were measured by an independent spinal surgeon. Physical activity was measured with the International Physical Activity Questionnaire (IPAQ). The “fear-avoidance” was measured with the Tampa Scale for Kinesiophobia (TSK). Back pain was assessed by the Graphic Rating Scale (GRS). The disability was assessed by the Roland–Morris Low Back Pain and Disability Questionnaire. Statistical interpretation of the data was performed using SPSS v19 software (SPSS Inc, Chicago, Illinois). Results: The sample included 51 patients underwent standard posterior laminectomy and instrumented fusion. Surgery has a positive global impact on the perceived low back pain. No significant (Spearman) correlations emerged among pelvic parameters and the pre- and post-surgical GSR. Patients were divided into three groups according to the IPAQ scores after the operation: “inactive” (I), “minimally inactive” (m-I), and “HEPA”. Significant differences emerged between IPAQ and Roland–Morris scores (F(2, 48) = 5.48, p = 0.007): the “inactive” (M(R-M) = 11.3) or “minimally active” (M(R-M) = 9.8) groups scored significantly higher than the “HEPA” group (M(R-M) = 4.7). Tampa scores correlated with gender (rho = −0.408, p = 0.003) and with BMI (rho = −0.369, p = 0.008). Females and obese patients reported higher levels of Tampa scores. Significant relationship was found between Tampa scores and pre-GSR (rho(pre) = 0.250, p = 0.08) and significant with post-surgical GSR (rho(post) = 0.275, p = 0.05) and with post-Roland–Morris score (rho(post) = 0.599, p < 0.01). Conclusion: The fear-avoidance and the physical inactivity are related to the highest levels of low back pain, more than pelvic imbalance. “Inactive” and “fear-avoidant” patients have also the worst outcome after surgery and the worst level of disability.