New CT scores give more accurate prognoses for patients with penetrating brain injury

Most traumatic brain injuries (TBI) treated in intensive care units are the result of a blunt instrument mechanism of injury, such as in falls or road traffic accidents, but a small proportion  of TBI are penetrating injuries caused, for example, by firearms or sharp objects.

Determining the patient’s prognosis are challenging in both trauma types. Injuries are generally assessed using CT scans of the head. For blunt trauma injuries, the prognostic estimates of CT findings are classified on the basis of dedicated scoring systems, among the most common and most accurately validated  of which are  the Marshall CT classification and the Rotterdam CT score. In addition there is the Helsinki CT score from Helsinki Uiversity Hospital  and the Stockholm CT score developed at the Karolinska University Hospital. A new study has described  a CT scoring system for penetrating traumatic brain injury (Lindfors M et al. Prognostic performance of computerized tomography scoring systems in civilian penetrating traumatic brain injury: an observational study. Acta Neurochir 2019 Oct 28. doi: 10.1007/s00701-019-04074-1).

“Prior to our study, the prognostic performance of scoring systems had not been assessed in relation to penetrating TBIs. This is why we wanted to investigate the extent to which different classifications can be used in establishing prognostic estimates for these trauma types” says Dr. Matias Lindfors, lead author.

To assess the prognostic performance of the classifications, the researchers analysed patient-record data and CT scans from all patients who had been treated for a penetrating TBI in the neurosurgical ICU of either the Töölö Hospital of the Helsinki University Hospital between or the Karolinska University Hospital.

The low number of patients included in the study, 75, in relation to the length of the observation period, indicates the rarity of the injuries in question. A partial explanation is the very selective nature of patient material, as the majority of patients with a penetrating traumatic brain injury die before reaching hospital care. Among this patient group, the number of suicide attempts is markedly high; in 64% of those included in the study, the injury was self-inflicted.

The study demonstrated that the Helsinki CT score, developed at the Helsinki University Hospital, was clearly more accurate compared to the older systems – with an accuracy of 90%, it was able to predict whether a patient would be alive six months after the injury. The prognostic performance of the Stockholm CT score was almost as good, at 85%.

The study also assessed how much added value these classification systems bring to other factors predicting recovery, namely age, level of consciousness and pupillary responsiveness. When only considering these three factors, the prognostic performance was approximately 90–95%, thus outperforming individual CT scoring systems – no significant increase in prognostic performance was provided by any of the scoring systems.

The prognosis of penetrating injuries has been considered fairly poor. However, according to the study, the prognosis of patients receiving active ICU treatment is comparable to that of patients with blunt TBI: 69% survived and as many as 49% regained functional independence.

Further improving treatment outcomes requires increasingly accurate patient selection. “The development of a scoring system specific for penetrating TBI aidS in targeting intensive care and surgical treatment as effectively as possible,” Lindfors says.