Injuries caused by fragmenting rifle ammunition

Although penetrating injuries are encountered on a regular basis in high volume trauma centres, most civilian trauma teams will be unfamiliar with the treatment of patients with injuries caused by fragmenting ammunition. The terrorist attacks in Norway on July 22, 2011 included a shooting spree causing 69 deaths and 60 injured. One of the weapons used was a semi-automatic rifle, calibre 5.56mm, with soft tip, short stop ammunition. The aim of the present study was to describe the characteristic injury patterns and lessons learned from the treatment of multiple patients admitted at the regional trauma centre with injuries from this type of ammunition.

We undertook an observational study of patients admitted at Oslo University Hospital, Ulleval after the shooting spree at Utoya on July 22, 2011. Data on demographics, injuries, injury severity, surgical procedures and outcome were collected prospectively.

Of the 21 patients admitted after the shooting incident, 18 were identified with injuries caused by fragmenting ammunition and included in the study. Median age was 17 years (IQR 16, 19), median ISS 21 (IQR 12, 30) and 12 patients were female. They had been hit by a total of 38 projectiles, of which 32 were fragmenting bullets. Of the seven patients who sustained injuries to the head, neck and face, one patient required a craniotomy and one patient had a non-survivable head injury. Of the 11 patients with torso injuries, six of the eight patients with chest injuries had intra-thoracic injuries that could be treated with chest tubes only. One patient had cardiac tamponade, requiring thoracotomy. Six patients underwent laparotomy, four of them more than one. Of the 10 patients with extremity injuries, two had nerve injuries and six patients had fractures. Five amputations were performed within the first nine days. A total of 101 operations were required within the first four weeks. The majority of these were repeated soft tissue debridements due to progressive necrosis.

Knowledge about the specific challenges created by the progressive soft tissue necrosis caused by fragmenting ammunition should lead to planned, repeated debridements to reduce total tissue loss and complications.