Muscle Quantity at C3 and/or L3 on Routine Trauma Series Computed Tomography Correlate With Brain Frailty and Clinical Frailty Scale: A Cross-Sectional Study

Background Sarcopenia (low muscle mass and function) is increasingly recognised to impact the quality of life and patient outcomes. The relationship with brain frailty is unknown. Objectives Assess if muscle mass at C3 correlates with muscle mass at L3 on routine trauma imaging. Assess for associations between muscle mass, brain frailty, and Clinical Frailty Scale (CFS) on routine trauma imaging. Methods Routine trauma-series computed tomography (CT) scans were retrospectively analysed for patients aged ≥16-years-old admitted to Queen Elizabeth Hospital in January 2020. Paravertebral, sternocleidomastoid, and total muscle cross-sectional area (CSA) at C3 (C3-SMM), and total psoas muscle CSA (TPA), total muscle CSA (L3-SMM), and total adipose CSA at L3 were calculated. Brain frailty scores were calculated assessing for leukoaraiosis, cerebral atrophy, and old vascular lesions/infarcts. CFS was calculated retrospectively from clinical notes. We assessed for correlation against age, CFS, muscle mass, and brain frailty using Pearson’s correlations. Results We included 111 patients in this study (mean age 49, SD 25.6; 65.8% female). C3-SMM strongly correlated with L3-SMM (r=0.746, p<0.001). Paravertebral and sternocleidomastoid CSA correlated with C3-SMM (paravertebral: r=0.814, p<0.001; sternocleidomastoid: r=0.814, p<0.001). TPA strongly correlated with L3-SMM (r=0.800, p<0.001). Sternocleidomastoid CSA and TPA both negatively correlated moderately with age (sternocleidomastoid: r=−0.460, p<0.001; TPA: r=−0.468, p<0.001), CFS (sternocleidomastoid: r=−0.414, p<0.001; TPA: r=−0.431, p<0.001), and brain frailty (sternocleidomastoid: r=−0.395, p<0.001; TPA: r=−0.436, p<0.001). Adipose CSA at L3 did not correlate with age, CFS, brain frailty, or muscle mass. Conclusion Muscle mass at C3 relates to muscle mass at L3. Muscle mass on routine trauma imaging is negatively associated with age, CFS, and brain frailty.