Incidence and risk factors for backpack palsy in young Korean soldiers

Objectives Backpack palsy (BPP) is a common aetiology of brachial plexopathy in military hospitals. We aimed to determine the incidence and risk factors of BPP in young Korean soldiers. Methods We identified enlisted patients who were diagnosed with BPP from a review of the medical records of all the Korean military hospitals in 2011 and 2012 and investigated their clinical findings and medical study results. To identify risk factors of BPP, we also surveyed, by questionnaire, healthy recruits of a company in a training centre who had just finished night marches. We divided them according to whether they had paresthaesia and/or weakness in their arm(s) during marching and compared their characteristics. Results The incidence of BPP in Korean soldiers was 29.7 per 100000 person-years (95% CI 17.2 to 24.3). Body mass index (BMI) was significantly lower in patients with BPP than it was in healthy recruits. Among healthy recruits, those who had experienced paresthaesia and/or weakness during marching had a significantly lower BMI than did those who had not. Conclusions We report the incidence of BPP in young Korean soldiers. A low BMI was a risk factor for BPP. These results may be helpful in establishing a strategy for the prevention of BPP in the setting of military training.