We aimed to determine the incidence and severity of spine injuries among severely injured trauma patients (Injury Severity Score (ISS)/New Injury Severity Score (NISS) > 15) treated in a single tertiary trauma center over 15 years. We also wanted to compare the demographics between patients with and without spine injuries and to determine the mortality of spine-injury patients. Data from the years 2006-2020 from the Helsinki Trauma Registry (HTR), a local trauma registry of the trauma unit of the Helsinki University Hospital (HUH), were reviewed. We divided patients into two groups, namely those with traumatic spine injury (TSI) and those without traumatic spine injury (N-TSI). TSI patients were further subdivided into groups according to the level of injury (cervical, thoracolumbar, or multilevel) and the presence of neurological symptoms. We included 2529 patients: 1336 (53%) had a TSI and 1193 (47%) had N-TSI. TSI patients were injured more frequently by a high-fall mechanism (37% vs 21%, p < 0.001). Among TSI patients, 38% of high-fall injuries were self-inflicted. High falls, young age, and female gender were overrepresented in spine-injury patients with a self-inflicted injury mechanism. Cervical spine-injury patients were mostly elderly persons injured by a low-energy mechanism. Unlike other severely injured trauma patients, severely injured trauma patients with spine injuries are more frequently injured by a high-fall mechanism and self-injury.