Over the last 150 years, the mortality rate in severe traumatic brain injury has dropped by nearly 50%. The reasons for this drop are not hard to comprehend-better understanding of the brain, improved therapies, and new technologies have all contributed to more people surviving.
However, a recent review of research has shown that the trend for decreased mortality has not been a smooth decline. Instead, there have been four specific periods of time that have been punctuated by major changes in the understanding of medicine, and also by changes in culture and demographics.
The review found the following trends:
- From the late 1800s to 1930, the average mortality rate fell 3% each decade. This drop appears to be related to an increased rejection of dangerous therapies such as extreme dehydration, trephination, or CSF drainage.
- From 1930 to 1970, there was no change in the mortality rate. During this time period, improved therapies such as ventilations, basic brain scanning, and resuscitation had been introduced. Also, there was a sharp increase in the number of neurosurgeons available in hospital. However, these improvements were offset by a tremendous increase of brain injury deaths by motor vehicle accidents.
- From 1970 to 1990, the average mortality rate fell 9%. This decrease is largely due to the introduction of the CT scan and ICP monitors. Additionally, research about better treatment was more efficiently circulated among clinicians.
- From 1990 until now, there has been no change in the mortality rate. Considering the tremendous advances in understanding and technology, this trend is more difficult to understand. The increased number of older adults, controversial outcomes from certain safety measures (airbags), treatment selectivity (where certain cases might not be given aggressive treatment) may all be factors in keeping the mortality rate steady in light of improved technology.
Currently, the rate of mortality is about 35% in severe TBI. Despite our increased understanding of the mechanisms of brain injury, as well as the apparent advances in therapies, the mortality rate in severe TBI has been steady for the last 20 years.
Stein, SC, Georgoff P, Meghan S, Mizra K, & Sonnan SS. 150 Years of treating severe traumatic brain injury: A systematic review of progress in mortality. Journal of Neurotrauma. (May 2010).