A Magnetic Resonance Imaging (MRI) Investigation of Cervical Spine Muscle Characteristics After Concussion: Identifying Return-to-Play Clearance and Subsequent Injury Prognosis.

We examined associations between magnetic resonance imaging (MRI)-obtained cervical spine flexor and extensor muscle fat infiltrate and muscle volume with (1) return-to-play clearance and (2) postconcussion injury incidence. Adolescents (N = 30, age = 15.8 ± 1.3 years, 60% female) underwent cervical spine MRI initially postconcussion and were monitored until return to play. After return-to-play clearance, participants underwent follow-up MRI and completed monthly injury surveys for 12 months. Cox proportional hazards regression examined associations between muscle fat infiltrate and muscle volume (1) initially postconcussion with return-to-play clearance and (2) at return-to-play with subsequent injury incidence. Adjusting for covariates, return-to-play clearance was not associated with cervical spine muscle fat infiltrate (hazard ratio [HR] = 0.99, 95% confidence interval [CI]: 0.96-1.02) or muscle volume (HR = 0.98; 95% CI: 0.96-1.01). Adjusting for covariates, postconcussion injuries were not associated with muscle fat infiltrate (HR = 0.90; 95% CI: 0.78-1.05) or muscle volume (HR = 1.01; 95% CI: 0.97-1.04). Cervical spine muscle characteristics may not be affected after concussion, or our MRIs may have occurred too early to capture postconcussion dysfunction.