Battlefield TBI: Blast and Aftermath
Battlefield TBI: Blast and Aftermath
Civilian cases of traumatic brain injury (TBI) account for more than 50,000 deaths annually and represent about 50% of deaths attributed to physical injury. These injuries are a significant medical and socioeconomic burden and represent one of the leading public health problems in the United States. However, thanks to injury prevention and changes in hospital admission practices, a decline of almost 50% in civilian hospitalizations for TBI has been observed since 1980, with many patients now treated on an outpatient basis.1 Improvements in TBI outcomes have been attributed to advances in critical care, improved imaging techniques, rapid surgical interventions, enhanced emergency care in trauma facilities, and innovative rescue systems.
TBIs can be classified as primary, resulting from the initial trauma, or as secondary, relating to intracranial pressure (ICP) elevations, hypoxia, or hypotension occurring as consequences of the primary insult. Among the important factors in improved TBI outcomes is the constant monitoring of ICP, which has allowed clinicians to intervene earlier. Increases in pressure are associated with increased mortality.1
Relatively few head injuries resulting from explosions occur in the civilian setting. Military personnel, however, experience more serious and unusual types of TBI than civilians because of exposure to battlefield bomb blasts. In the battlefield setting, closed brain injury—often accompanied by progressive hemorrhagic problems—is common, and incidence of penetrating brain injuries is higher than that seen in other venues.2
Of all military personnel who experienced injuries because of hostile fire in Iraq and Afghanistan and who were evacuated to Walter Reed Army Medical Center (WRAMC), 28% had a TBI.3 This is consistent with data from the Joint Theater Trauma Registry, published by the US Army Institute of Surgical Research, which revealed that 22% of soldiers from both war zones who were processed through the military's Regional Medical Center in Landstuhl, Germany, experienced injuries to the head, face, or neck.4 This percentage serves as an estimate of the proportion of soldiers who have sustained TBI, according to WRAMC and the Defense and Veterans Brain Injury Center (DVBIC). The actual percentage may be higher, since many cases of closed brain injury are not promptly diagnosed.4
Since November 4, 2006, blasts have been the most common cause of injury among American soldiers treated at WRAMC. Indeed, the most commonly treated wound seen in American soldiers serving in the current conflicts in Iraq and Afghanistan has been the blast injury. One report5 noted that 88% of Operation Iraqi Freedom-associated injuries treated at a second-echelon military medical center were the result of blasts.
TBI has been associated with 59% of blast-associated injuries seen at WRAMC,6 and military statistics reveal that more than 1700 soldiers have sustained a TBI since the beginning of the Iraqi and Afghan operations.3
Brain injuries received in Iraq and Afghanistan often have been classified as "head and neck" wounds, making the actual number of TBIs difficult to ascertain and making comparison with data on TBI gathered from previous wars difficult.3
ON THE BATTLEFIELD
"Soldiers in the field suffer blast injuries that often result in having mud, gravel, and other contaminated projectiles enter the brain tissue. These injuries often are the result of roadside bombs," explained Gerald A. Grant, MD, assistant professor of pediatric neurosurgery at Duke University Medical Center in Durham, North Carolina. Recently returned from active duty as a lieutenant colonel in the Air Force, Grant served as a neurosurgeon in the US military hospital in Landstuhl, Germany, where he had the opportunity to provide care to US and Coalition troops stationed in Baghdad during 2005 and 2006.
"Often debris and other projectiles revealed by CT were so abundant that we had to leave fragments in the brain after removing the largest and most dangerous pieces," Grant told Applied Neurology. "Sections of the skull were removed for decompression purposes to offset the damage caused by edema." When brain swelling was reduced, a skull flap was sewn into place.
"When we treat TBI in soldiers, we first control hemorrhage using factor VII-A, which allows us to do an extensive and deep debridement of foreign bodies that lodge in brain tissue," Grant explained. "Edema is well controlled with dexamethasone. Because of the entry of contaminated material into the brain, infection usually caused by Acinetobacter requires the use of intravenous antibiotics preoperatively, perioperatively, and postoperatively."
Although synthetic skull flaps, which are not compromised by the problem of bone resorption, "produce excellent results," their use is not always feasible in the battlefield setting, according to Grant. "Sections of skull [to later be used as skull flaps] were placed in the subcutaneous tissues of the abdomen for preservation because freezing facilities were not available," he said. "Because of lack of basic facilities, skull removed from nonmilitary patients treated for TBI, such as Iraqis and even insurgents, would be temporarily preserved by abdominal implantation. After brain swelling was reduced, these pieces were retrieved and sewn into place as skull flaps. Over time, however, a small amount of bone resorption occurred."
Wounded soldiers receive immediate battlefield care and are then transported by helicopter to military combat hospitals. "This rapid evacuation of the wounded to high-level medical and surgical facilities has resulted in survival rates of almost 96%," reported Grant. "We triage the wounded very quickly using CT and a careful examination of the wound."
At Grant's post in Germany, maxillofacial surgeons; ear, nose, and throat surgeons; neurosurgeons; and other specialists worked as close-knit, integrated teams to serve military personnel who experienced TBI. "Of course, the medics who saw the wounded first were often able to start central lines and provide hydration, antibiotic support, and some decompression techniques before victims reached advanced medical facilities. The immediate attention and expertise of the medics was invaluable in pushing survival rates as high as they were," said Grant.
Many soldiers are then transferred to 1 of 8 DVBIC participating hospitals in the United States for further assessment and treatment. Wounded soldiers who are sent to WRAMC undergo assessment of the severity of their TBI largely based on the duration of loss of consciousness and post-traumatic amnesia.
"When soldiers were brought to the military hospital, they were often in very serious condition or comatose," said Grant. Families were encouraged to visit with patients after they received treatment. "Our first job was to prepare the wounded for return to the battlefield. Soldiers whose wounds were too serious for recall to active duty often were disappointed that they could not return to their former theaters of action," Grant commented. "Their sense of camaraderie was very strong, and most wanted to return to active duty to be with their buddies. Memory loss, attention deficit, verbal memory loss, and the loss of executive functioning were the most serious reasons for sending soldiers home."
Soldiers who have experienced mild TBI usually fully recover within a year. However, those with moderate to severe TBI are likely to have lingering neurological deficits. Depression, post-traumatic stress syndrome, and loss of psychosocial skills are frequent sequelae of TBI, said Grant.
Reintegration into civilian life has been a major focus of governmental response to wartime TBI. In 1990, President George H. Bush signed the Americans With Disabilities Act, which, among other stipulations, entitles persons experiencing deficits caused by battlefield TBI to fair practices in housing accommodation and in public spaces. In 1996, President Bill Clinton signed the Traumatic Brain Injury Act, which focused greater attention on the broad needs of persons who have experienced brain injury.7
"It is difficult to say with any certainty what the long-term prognosis is for wounded soldiers who have suffered brain damage," said Grant. "In a military setting, long-term follow-up is difficult. However, efforts are now under way to follow patients through the various stages of rehabilitation. New technologies use satellite video and e-mail allows physicians and surgeons to closely monitor patients.
"Results from long-term follow-up will not only help wounded soldiers adapt to civilian circumstances," Grant continued, "but much of the information derived from the treatment of wartime wounded will ultimately benefit the civilian population in the diagnosis, treatment, and rehabilitation of brain injury."
1. Baron EM, Jallo JI. TBI: pathology, pathophysiology, acute care and surgical management, critical care principles, and outcomes. In: Zasler ND, Katz DI, Zafonte RD, eds. Brain Injury Medicine: Principles and Practice. New York: Demos; 2007:265-281.
2. Warden DL, Ryan LM, Helmick KM, et al. War neurotrauma: the Defense and Veterans Brain Injury Center (DVBIC) experience at Walter Reed Army Medical Center (WRAMC). J Neurotrauma. 2005;22:1178. Abstract.
3. Warden D. Military TBI during the Iraq and Afghanistan wars. J Head Trauma Rehabil. 2006;21:398-402.
4. Okie S. Traumatic brain injury in the war zone. N Engl J Med. 2005;352: 2043-2047.
5. Murray CK, Reynolds JC, Schroeder JM, et al. Spectrum of care provided at echelon II Medical Unit during Operation Iraqi Freedom. Mil Med. 2005; 170:516-520.
6. Okie S. Reconstructing lives—a tale of two soldiers. N Engl J Med. 2006;355: 2609-2615.
7. Zitnay GA. Brain injury rehabilitation: past, present, and future? In: Zasler ND, Katz DI, Zafonte RD, eds. Brain Injury Medicine: Principles and Practice. New York: Demos; 2007:15-19.