Gun-shot injuries in UK military casualties - Features associated with wound severity.

INTRODUCTION: Surgical treatment of high-energy gun-shot wounds (GSWs) to the extremities is challenging. Recent surgical doctrine states that wound tracts from high-energy GSWs should be laid open, however the experience from previous conflicts suggests that some of these injuries can be managed more conservatively. The aim of this study is to firstly characterise the GSW injuries sustained by UK forces, and secondly test the hypothesis that the likely severity of GSWs can be predicted by features of the wound. METHODS: The UK Military trauma registry was searched for cases injured by GSW in the five years between 01 January 2009 and 31 December 2013: only UK personnel were included. Clinical notes and radiographs were then reviewed. Features associated with energy transfer in extremity wounds in survivors were further examined with number of wound debridements used as a surrogate marker of wound severity. RESULTS: There were 450 cases who met the inclusion criteria. 96 (21%) were fatally injured, with 354 (79%) surviving their injuries. Casualties in the fatality group had a median New Injury Severity Score (NISS) of 75 (IQR 75-75), while the median NISS of the survivors was 12 (IQR 4-48) with 10 survivors having a NISS of 75. In survivors the limbs were most commonly injured (56%). 'Through and through' wounds, where the bullet passes intact through the body, were strongly associated with less requirement for debridement (p<0.0001). When a bullet fragmented there was a significant association with a requirement for a greater number of wound debridements (p=0.0002), as there was if a bullet fractured a bone (p=0.0006). CONCLUSIONS: More complex wounds, as indicated by the requirement for repeated debridements, are associated with injuries where the bullet does not pass straight through the body, or where a bone is fractured. Gunshot wounds should be assessed according to the likely energy transferred, extremity wounds without features of high energy transfer do not require extensive exploration.