Rationalising neurosurgical head injury referrals: The development and implementation of the Liverpool Head Injury Tomography Score (Liverpool HITS) for mild traumatic brain injury

Objectives: To develop and implement a radiological scoring system to define a surgically significant mild Traumatic Brain Injury (TBI), stratify neurosurgical referrals and improve communication between referral centres and neurosurgical units. Design: Retrospective single centre case-control analysis of ten continuous months of mild TBI referrals. Setting: A major tertiary neurosurgery centre in England, UK. Participants: All neurosurgical referrals with a mild TBI (GCS 13-15) during the period of 1st January to 30th October 2017 were eligible for the study. 1248 patients were identified during the study period, with 1444 being included in the final analysis. Interventions: All patients CT head results from the referring centres were scored retrospectively using the scoring system and stratified according to their mean score, and if they were accepted for transfer to the neurosurgical centre or managed locally. Main outcome measure: Determine the discriminatory and diagnostic power, sensitivity and specificity of the scoring system for predicting a surgically significant mild TBI. Results: Most patients referred were male (59.4%, N=681), with a mean age of 69 years (SD=21.1). Of the referrals to the neurosurgical centre, 17% (n=195) were accepted for transfer and 83% (n=946) were not accepted. The scoring system was 99% sensitive and 51.9% specific for determining a surgically significant TBI. Diagnostic power of the model was fair with an area under the curve of 0.79 (95% CI 0.76 to 0.82). The score identified 495 (52.2%) patients in ten months of referrals that could have been successfully managed locally without neurosurgical referral if the scoring system was correctly used at the time of injury. Conclusion: The Liverpool Head Injury Tomography Score (HITS) score is a CT based scoring system that can be used to define a surgically significant mild TBI. The scoring system can be easily used by multiple healthcare professionals, has high sensitivity, will reduce neurosurgical referrals, and could be incorporated into local, regional and national head injury guidance.