Background Previous research has shown that injuries to the head and neck were prevalent in 73% of all mounted fatalities of underbody blast. The mechanisms that cause such injuries to the central nervous system are not yet known. The aim of this study was to identify the head and spinal injuries in fatalities due to underbody blast and then develop hypotheses on the causative mechanisms.
METHODS All UK military fatalities from underbody blast who suffered a head injury from 2007-2013 in the Iraq and Afghanistan conflicts were identified retrospectively. Post-mortem CTs (PMCTs) were interrogated for injuries to the head, neck and spine. All injuries were documented and classified using a radiology classification. Chi-squared and Fisher's Exact tests were used to reject independence and form a hypothesis for injury mechanisms.
RESULTS There were 50 fatalities from underbody blast with an associated head injury. Of these, 46 had complete CTPM's available for analysis. Chi-squared and Fisher's exact showed independence could be rejected for lateral ventricle blood and injuries to the abdomen and thorax.
CONCLUSIONS Five partially overlapping injury constellations were identified: 1. Multiple level spinal injury with skull fracture and brainstem injury. 2. Perimesencephalic haemorrhage. 3. Spinal and Brainstem injury. 4. Parenchymal contusions with injury to C0-C1. 5. An eggshell pattern of fractures from direct impact. These hypothesised mechanisms can now be investigated to consider mitigation strategies or clinical treatments.