Investigating the Relationship Between Paraspinal Fatty Muscle Infiltration (FMI) and the Severity of Degenerative Lumbar Canal Stenosis (LCS): A Correlation Analysis

Study DesignProspective observational study. ObjectiveThis study aimed to correlate the degree of paraspinal muscle fatty infiltration with the severity of lumbar canal stenosis, the demographic characteristics of the patient, the radiological parameters, and clinical scores. Material and MethodologyThis is a single-centre observational study in patients with secondary degenerative lumbar canal stenosis in patients older than 35 with radiological features matching the clinical symptoms. The demographic characteristics, fatty muscle infiltration (FMI) grade of multifidus and erector spinae muscles, lumbar canal stenosis (LCS) grade, neurological status, visual analogue scale (VAS) score, oswestry disability index (ODI) score, and endplate modic changes were recorded. The statistical analysis was done using SPSS v.25. For the comparison of categorical variables between groups, a chi-square test was used. A p-value <0.05 was considered to be statistically significant. ResultsThe mean age of the study participants was 62.2 ±10.9 years. Of the 150 patients, 60.7% were women. The mean BMI of the patients was 27.8 ± 2.8 kg/m2. 121(80.7%) patients presented with low back pain at their first visit. 36.7% of the patients presented with claudication symptoms at their first visit. It was observed that 3.3% of the patients presented with cauda equina syndrome (CES). The mean duration of symptoms was 20.9 ± 16.3 months. The mean VAS score at the presentation was 5.9 ± 1.3. The mean ODI score at the first visit was 27.7 ± 6.1. Fatty muscle infiltration of the multifidus but not the erector spinae is associated with higher pain and ODI scores. The grade of FMI does not significantly correlate with the grade of LCS. Age significantly affects degenerative paraspinal muscle changes independent of the pathology. Other factors like BMI, gender, presence or absence of modic changes do not significantly affect the severity of stenosis, degree of paraspinal muscle fatty infiltration, and the pain and disability scores of the patients. ConclusionThe study revealed that the grade of FMI does not significantly correlate with the grade of degenerative lumbar canal stenosis. Age significantly affects degenerative paraspinal muscle changes independent of the pathology.