150 years of treating severe traumatic brain injury: a systematic review of progress in mortality.

Considerable effort and resources have been devoted to preserving life in patients with severe closed traumatic brain injury (TBI). We sought to identify temporal trends in mortality rates of these patients from the late 1800s to the present. We searched the literature for articles on severe TBI, abstracting numbers of patients studied, numbers of deaths, and years of patient entry. Mortality rates were calculated for each study, and meta-regression was used to pool data and to test for significant temporal trends. We reviewed 207 case series comprising more than 140,000 cases of severe closed TBI admitted to hospital over a span of almost 150 years. Since the late 1800s mortality has fallen by almost 50%. However, the rate has varied considerably among the four epochs chosen. Between 1885 and 1930, mortality decreased at a rate of 3% per decade. From 1970 to 1990, mortality declined at a rate of 9% per decade. Both changes are significant. There was no observed improvement in mortality between 1930 and 1970, nor is progress evident since 1990. The authors discuss possible reasons for the apparently intermittent progress in TBI survival over time.