Relationship Between Paraspinal Sarcopenia and Lumbar Alignment and Facet Joint Osteoarthritis in Patients with Degenerative Lumbar Spinal Stenosis

Study Design. Retrospective study analysis. Objective. To explore association between degenerative spinal conditions and paraspinal sarcopenia in patients with severe degenerative lumbar spinal stenosis (DLSS). Background. Paraspinal muscles plays an essential role in stabilizing the spine. Paraspinal sarcopenia is progressively recognized as a crucial parameter influencing clinical outcomes in the field of spine surgery. The association between degenerative spinal conditions and paraspinal sarcopenia in patients with severe DLSS has been rarely investigated. Materials and Methods. This study was conducted on consecutive patients who underwent posterior lumbar interbody fusion at L4/5 single-level for lumbar spinal stenosis between January 2019 and July 2023. The study assessed paraspinal sarcopenia based on the fatty infiltration and Goutallier classification systems (GCS) of multifidus muscle on preoperative magnetic resonance imaging. The study evaluated the association between demographic/radiographic factors and paraspinal sarcopenia in patients with DSLL. Ordinal logistic regression analysis was then performed to adjust for confounding. Results. A total of 129 patients were included, including 38 patients with mild paraspinal sarcopenia, 52 patients with moderate paraspinal sarcopenia, and 39 patients with severe paraspinal sarcopenia. Correlation analysis indicated that age (r=0.366, P <0.001), pelvic incidence (PI) (r=0.407, P <0.001), lumbar lordosis (LL) (r=0.362, P =0.023) were positively correlated with paraspinal sarcopenia, while weight (r=−0.422, P <0.001), cross-sectional area (CSA) of psoas (r=−0613, P <0.001), facet joint angle (FA) (r=−0.447, P =0.016), and The Hounsfield Unit values of L1-L4 (L1-4 HU) (r=0.298, P =0.005) were negatively correlated with paraspinal sarcopenia. Ordinal logistic regression showed that the Facet joint osteoarthritis (FJOA) (odds ratio=2.82, P =0.017), PI (odds ratio=1.15, P <0.001), age (odds ratio=1.14, =0.001), and female (odds ratio=5.26, P =0.04) were associated with paraspinal sarcopenia. Conclusions. Our study demonstrated FJOA, PI, age, and female were associated with paraspinal sarcopenia. The assessments of paraspinal muscles cross-sectional area were not associated with the severity of fatty infiltration.