According to the findings of this study, the incidence of ED visits due to TBI decreased after the declaration of a national lockdown in March 2020,with the lowest incidence being observed in April. Thereafter, the incidence rebounded to the same level as in the reference years. This rebound may have been the result of various changes in peoples’ behavior. First, the actual incidence of TBI may have decreased. In addition, most sport and leisure activities were banned during the lockdown, and people were encouraged to work from home. As a result, commuting and traffic volumes decreased, and fewer traffic accidents occurred. Second, citizens were told to avoid unnecessary ED visits, and thus some of the patients with mild TBI/concussion may have avoided seeking medical treatment. These changes may therefore have been some of the main factors behind the changes in incidence rates. Previous studies concerning the first wave of the pandemic have reported similar findings [5–9].
During the second wave of the COVID-19 pandemic in December, the incidence of ED visits due to TBI showed a second decrease. Restaurant and bar restrictions during the national lockdown may have resulted in individuals consuming less alcohol or shifting the place of alcohol consumption from bars to their home. This may, in turn, have led to a decreased incidence of TBIs, as alcohol is a major risk factor for TBI [4].
In the present study, we found that the incidence of trauma craniotomies and craniectomies decreased during the period of restaurant restrictions, being the lowest in May. When the restaurants reopened in June, the incidence of trauma craniotomies and craniectomies rebounded to the same level as in previous years. A decreasing trend in the incidence of trauma craniotomies and craniectomies may be linked to the decrease in the number of TBIs, since fewer TBIs may have led to a reduction in emergency neurosurgery. Indeed, reductions in elective neurosurgery during the COVID-19 pandemic have been reported [11–13, 18], with elective operations canceled or rescheduled to prioritize health care resources and to reduce non-urgent treatment. Similar findings have been reported in emergency neurosurgery [14]. However, according to a previous study from Finland, the nationwide restrictions did not result in a decrease in the number of patients with TBI neurosurgically treated [10].
The strengths of our study include the broad data from three large Finnish hospitals. Furthermore, many previous studies have only evaluated the impact of the first wave of the COVID-19 pandemic. In this study, we were able to collect follow-up data from all patients during the first and second waves of the COVID-19 pandemic and to evaluate the impact of re-opening and restrictions during the second wave. Our current study also has some limitations. Since we aimed to evaluate only trauma patients, we only included specific ICD-10 diagnostic codes. Owing to the retrospective and administrative nature of the present study, we were unable to separately study the different severities of TBI. Moreover, due to the register-based design and uncertainty related to the reliability of ICD-10 and NOMESCO coding, we were only able to evaluate trauma craniotomies and craniectomies, and other neurosurgical traumas were excluded.
In conclusion, the incidence of ED visits due to TBI decreased after the declaration of national lockdown in spring 2020, and a second decrease was observed after the implementation of regional restrictions in December. In addition, the incidence of trauma craniotomies and craniectomies decreased during the restaurant restrictions implemented in the spring. As expected, the COVID-19 pandemic and nationwide restrictions resulted in a decreasing trend in the incidence of ED visits due to TBI and neurosurgically treated TBI. This finding should be noted when planning further restrictions.