Effects of Concomitant Traumatic Spinal Cord and Brain Injury on In-Hospital Mortality: A Retrospective Analysis of a Nationwide Trauma Registry in Japan.

Isolated traumatic spinal cord injury (t-SCI) and traumatic brain injury (TBI) represent significant public health concerns, resulting in long-term disabilities and necessitating sophisticated care, particularly when occurring concurrently. The impact of these combined injuries, while crucial in trauma management, on clinical, socioeconomic, and health care outcomes is largely unknown. To address this gap, our secondary retrospective cohort study used data from the Japan Trauma Data Bank, covering patients enrolled over a 13-year period (2006-2018), to elucidate the effects of concurrent t-SCI and TBI on in-hospital mortality. Data on patient demographics, injury characteristics, treatment modalities, and outcomes were analyzed. Multivariate logistic regression analysis was performed to examine prognostic variables associated with in-hospital mortality, including interaction terms between t-SCI severity and TBI presence. This study included 91,983 patients with neurotrauma, with a median age of 62 years (69.7% men). Among the patients, 9,018 (9.8%) died in the hospital. Concomitant t-SCI and TBI occurred in 2,954 (3.2%) patients. t-SCI only occurred in 9,590 (10.4%) patients, whereas TBI only occurred in the majority of these cases (79,439, 86.4%). Multivariate logistic regression analysis revealed age; sex; total number of comorbidities; systolic blood pressure at presentation; Glasgow coma scale score at presentation; and Abbreviated Injury Scale (AIS) scores for head, face, chest, abdomen, cervical-SCI, thoracic-SCI, and lumbar-SCI as significant independent factors for in-hospital mortality. The odds ratio of cervical-SCI × head AIS as an interaction term was 0.85 (95% confidence interval: 0.77-0.95), indicating a negative interaction. In conclusion, we identified 12 factors associated with in-hospital mortality in patients with t-SCI. In addition, the negative interaction between cervical t-SCI and TBI suggests that the presence of t-SCI in patients with TBI may be underestimated. This study highlights the importance of early recognition and comprehensive management of these complex trauma conditions while considering the possibility of concomitant t-SCI in patients with TBI.