Brain injury severity and autonomic dysregulation accurately predict heterotopic ossification in patients with traumatic brain injury

Abstract

Objective : To assess brain injury severity, autonomic dysregulation and systemic infection as risk factors for the occurrence of heterotopic ossification in patients with severe traumatic brain injury. Design : Historic cohort study. Setting : Radboud University Medical Centre. Subjects : All consecutively admitted patients with severe traumatic brain injury (admission Glasgow Coma Scale score 8 or less) during the years 2002—2003. Main measures : The development of clinically relevant heterotopic ossification, defined as painful swelling of joints with redness and decreased range of motion, confirmed radiographically. Results : Seventy-six (64%) of the 119 patients survived and were eligible for further follow-up. Nine patients (12%) developed 20 symptomatic heterotopic ossifications, in one or more joints. Patients with heterotopic ossification had sustained more severe brain injuries, compared to the group without heterotopic ossification. The mean coma duration in the heterotopic ossification group was 28.11 days (SD 20.20) versus 7.54 days (SD 7.47) in the patients without heterotopic ossification (P < 0.001). The occurrence of autonomic dysregulation (relative risk (RR) 59.55, 95% confidence interval (CI) 8.39—422.36), diffuse axonal injury (RR 20.68, 95% CI 4.92—86.91), spasticity (RR 16.96, 95% CI 3.96—72.57) and systemic infection (RR 13.12, 95% CI 3.01—57.17) were all associated with an increased risk of developing symptomatic heterotopic ossification. However, only autonomic dysregulation had a high positive (88.9%, 95% CI 51.7—99.7) and negative (98.5%, 95% CI 91.9—99.9) predictive value with regard to heterotopic ossification. Conclusions : The occurrence of autonomic dysregulation may predict the chance of developing heterotopic ossification in patients with severe head injury.