A recent systematic review of the current medical literature on blast-related injuries among Operation Enduring Freedom (OEF), Operation Iraqi Freedom (OIF), and Operation New Dawn (OND) service members from 2001 through 2014 found limited information about the true incidence (number of new cases that develop over a specific time period for deployed population) and prevalence (proportion of deployed population who have or had a blast-related injury in a given time period) of bomb-blast injury. The review of the literature, conducted by the Evidence-based Synthesis Program (ESP) center based at the Minneapolis VA Health Care System, also found limited evidence on outcomes associated with blast versus non-blast traumatic brain injury (TBI).
Accurate assessment of the risk and number of blast-related injuries, as well as their long-term outcomes, is important given the greater use of improvised and other explosive devices in the Afghanistan and Iraq Wars relative to prior conflicts. Additionally, understanding the differences between TBI related to blast exposure and TBI due to other mechanisms can affect treatment options and management. Gathering data in both of these areas is a critical first step in injury prevention, treatment, and health system resource management.
Six studies, three of which were derived from the same data set, provided information about the incidence and prevalence of blast-related injuries in the deployed population at risk. Thirty-four studies reported on blast versus non-blast TBI, but most were small studies of individuals presenting to medical facilities and undergoing treatment with outcomes assessment at different time points following blast exposure. Few studies reported information about the blast exposure (e.g., blast mechanism, distance from blast, or history of blast exposure). Below are the main report findings on incidence, prevalence, and blast versus non-blast TBI.
- The reported explosion injury incidence ranged from 4.5/1,000 deployed in 2005 to 1.7/1,000 deployed in 2009.
- During the Iraq troop surge (2007) explosion injury incidence was particularly high (83/1,000 deployed in a US Army Brigade Combat Team).
- Musculoskeletal explosion injury incidence (fractures, amputations, neurological injuries, joint dislocations, and soft tissue injuries) ranged from 3.5/1,000 deployed in 2005 to 1.3/1,000 deployed in 2009.
- Nearly three-quarters of all combat injuries from 2005 to 2009 (31 per 10,000 deployed) were due to explosions.
- A high proportion of musculoskeletal injuries (82%; 23 per 10,000 deployed) and spinal injuries (75%; 3 per 10,000 deployed) between 2005 and 2009 were due to explosions. Of the musculoskeletal injuries, 80% of axial skeletal and extremity fractures, 94% of amputations, and 85% of soft tissue injuries were explosion-related. Another study reported explosion-related amputations in 4 per 10,000 troop-years (Iraq) and 9 per 10,000 troop-years (Afghanistan) from 2001 to 2011.
Blast versus non-blast TBI
- Blast and non-blast TBI groups had similar rates of pain, vision loss, vestibular dysfunction, functional ability, depression, sleep disorders, alcohol misuse, and post-concussive symptoms.
- Comparative outcomes in individuals with blast versus non-blast TBI were inconsistent across studies with regard to PTSD diagnosis or symptom severity, hearing loss, cognitive function, and headache in blast and non-blast TBI groups.
- Mortality, burn injuries, limb loss, and quality of life were rarely reported.
Report authors concluded that to more adequately address questions about consequences of blast exposure, future research efforts should focus on comprehensive and consistent documentation at the time of and following blast exposure and more complete analyses of databases that may already have captured blast exposure information.