Duration of Back Pain Symptoms and Its Relationship to Paralumbar Muscle Volume.

OBJECTIVE: Paralumbar muscle volume has been indicated as an important factor for patients reporting back pain. Our goal was to determine if there is a statistically significant relationship between the duration of patients back pain symptoms (>12 weeks or ≤12 weeks) and paralumbar muscle volume (PLMV).

METHODS: In this retrospective cohort study paralumbar muscles on axial T2-weighted lumbar MRIs were outlined using ImageJ to determine the Paralumbar cross-sectional area (PL-CSA) and lumbar indentation value (LIV) at the center of disc spaces from L1 to L5. Goutallier Classification was determined by the primary author. Quantile regression was performed to compare the PL-CSA, PL-CSA normalized by BMI (PL-CSA/BMI), and LIV between the two cohorts. Cohort A consisted of patients reporting symptoms ≤12 weeks, and Cohort B included patients with symptoms >12 weeks. Negative binomial regression was used to compare Goutallier class.

RESULTS: A total of 551 patients of a single surgeon with a lumbar MRI within the past 12 months and recorded duration of symptoms were included. Cohort A consisted of 229 patients (41.6%), and Cohort B included 322 patients (48.4%). Statistical significance was not found at any lumbar level for PL-CSA, PL-CSA/BMI, Goutallier class and LIV.

CONCLUSION: Our results suggest that duration of symptoms may not be an accurate indicator for lumbar muscle volume. These novel findings are clinically valuable as lumbar muscle volume has been shown to be a marker for recovery. With this information patient's previously thought to be inoperable due to longstanding symptoms can be re-evaluated.