Traumatic brain injury in alpine winter sports: Comparison of two case series from a Swiss trauma center 30 years apart.

BACKGROUND: Between 3-15% of winter sports-related injuries are attributed to head injury, which is the primary cause of mortality and disability among skiers. Despite the widespread adoption of helmets in winter sports, which has been proven to reduce the incidence of direct head injury, there is a paradoxical trend where an increasing number of individuals wearing helmets are sustaining diffuse axonal injuries (DAI), which can result in severe neurological sequelae.

METHODS: We retrospectively reviewed 100 cases collected by the senior author of this work from 13 full winter seasons during the 1981-1993 period and compared them with the 17 patients admitted during the more 2019-2020 ski season shortened due to COVID-19. All data analyzed comes from a single institution (Sion Cantonal Hospital, Switzerland). Population characteristics, mechanism of injury, helmet use, need for surgical treatment, diagnosis and outcome were collected. Descriptive statistics were used to compare the two databases.

RESULTS: From February 1981 to January 2020, most head injured skiers were men (76% and 85% respectively). The proportion of patients aged over 50, increased from less than 20% to 65% in 2020 (p<0.0001), with a median age of 60 years old (range of 22-83 years). Low-medium velocity injuries were identified in 76% (13) of cases during the 2019-2020 season against 38% (28/74) during the 1981-1993 seasons (p<0.0001). All injured patients during the 2020 season wore a helmet, whereas none of the patients wore one between 1981-1993 (p<0.0001). Diffuse axonal injury was observed in 6 cases (35%) against 9 cases (9%) for the 2019-2020 and 1981-1993 seasons respectively (p<0.0001). 34% (34) of patients during the 1981-1993 seasons and 18% (3) of patients during season 2019-2020 suffered skeletal fractures (p=0.02). Among the 100 patients of the 1981-1993 seasons 13 (13%) of them died against 1 (6%) from the recent season during care at the hospital (p=0.15). Neurosurgical intervention was performed in 30 patients (30%) against 2 patients (12%) for the 1981-1993 and 2019-2020 seasons respectively (p=0.003). Neuropsychological sequelae were reported in 17% (7/42) of patients from the 1981-1993 seasons and cognitive evaluation before discharge detected significant impairments in 24% (4/17) of the patients from the 2019-2020 season (p=0.29).

CONCLUSION: While helmet use among skiers sustaining head trauma has increased from none between the 1981-1993 period to 100% during the 2019-2020 season, resulting in a reduction in the number of skull fractures and deaths, our observations suggest a marked shift in the type of intracranial injuries sustained, including a rise in the number of skiers experiencing diffuse axonal injury (DAI) with sometimes severe neurological outcomes. The reasons for this paradoxical trend can only be speculated upon, leading to questioning whether the perceived benefits of helmet use in winter sports are actually misinterpreted.