The rehabilitation of veterans and active-duty service members (ADSMs) is one of the most demanding of all rehabilitation populations. The rehabilitation of this population is a complex task requiring the coordination of an interdisciplinary team. The severity of the disorder dictates the resources that are required and the personnel involved in the care of the patient.

Clinicians in the U.S. Department of Defense (DoD) and the U.S. Department of Veterans Affairs (VA) need to understand the impact of combat and noncombat operations on the body’s function. It is common for ADSMs to return from deployment with a diverse range of difficulties. In addition, more than 50% of returning ADSMs enroll in the VA’s health care system for treatment of their difficulties, including service-related conditions. Therefore, it is imperative that the clinicians providing their care become familiar with the strain that military life may put on an individual. This chapter describes the specific exposures, injuries, and illnesses that rehabilitation professionals commonly treat in the DoD and VA. In recent years, concern about combat-associated traumatic brain injury (TBI) and posttraumatic stress disorder (PTSD) has been at the forefront of clinical care and research pathways. This chapter will focus on those issues, adding a brief description of other conditions related to military service.

VA specifically documents exposure-related health concerns (Box 100–1) to increase clinician and veteran knowledge about a variety of illness and injuries and to facilitate a systematic approach to care, including (1) Agent Orange, (2) Gulf War syndrome (GWS), (3) infectious diseases of Southwest Asia, (4) toxic embedded fragments, (5) TBI, (6) radiation exposure, (7) chemical, biological, and radiological weapons, (8) cold injuries, and (9) heat injuries. In addition, the VA created the Veterans Health Initiative (VHI) to knowledge-translate and disseminate these topics in greater detail for the purpose of providing enhanced understanding of these conditions that primarily affect ADSMs and veterans. In parallel, a better appreciation of these issues facilitates the DoD’s ability to prepare and protect American service members in future operations (i.e., force readiness).

During the Vietnam War, Agent Orange, a broad-spectrum herbicide, was used to clear foliage and improve battlefield visibility for troops. It was only after its use that its potential negative health impacts were understood. VA relates many illnesses in veterans and their children to the use of this toxicant (Box 100–2). Rehabilitation professionals should be familiar with these illnesses and disorders as many of them affect function and will respond to therapy and other interventions.

During the first Gulf War in the early 1990s, U.S. troops were exposed to a variety of environmental toxins and neurotoxins. In 2008, the Research Advisory Committee on Gulf War Veterans’ Illnesses documented that exposure to pesticides and pyridostigmine (an antinerve gas medication) combined to cause the multisymptom illness known as GWS. Symptoms of GWS include fatigue, headaches, joint pain, gastrointestinal (GI) problems, insomnia, memory deficits, and respiratory difficulties. Further, chronic fatigue syndrome, fibromyalgia, other GI disorders, and several difficult-to-diagnose illnesses also may be associated with service in the Gulf War.

Veterans of World War II, the Korean War, and Operation Enduring Freedom (OEF), which refers to the U.S. military operations in Afghanistan, as well as other activities in the so-called war on terror, also may have been exposed to cold injuries. The Battle of the Bulge (1944–1945), the Chosin Reservoir Campaign (1950), and a variety of mountain skirmishes during OEF were all fought in subzero temperatures. Due to the exposure to extreme weather conditions, veterans of these operations may suffer from consequences of frostbite, including neurologic injury, vascular injury, skin disorders, musculoskeletal difficulties, and soft tissue disorders. Additionally, veterans who served in the Gulf War, OEF, and Operation Iraqi Freedom (OIF), referring to the second Gulf War, from 2003 to 2010, also may fight in desert climates with extreme heat. These veterans were at risk of heat-related injuries, such as heat stroke, exhaustion, and sunburn. Although none of these injuries or illnesses is at the forefront of research today, they are still issues that every medical personnel need to be aware of.

During peacetime, the incidence of TBI in military personnel surpasses that seen in the civilian population; rates of TBI in military women rise to rates similar to those observed in the male civilian population.¹ Distinct from all other war injuries, TBI was identified as “the signature injury” of the War on Terror and was caused by the majority of blast injuries, which accounted for 81% of all OEF/OIF injuries.^2,3 This high percentage of blast injuries is significantly higher than prior wars, which had blast injuries accounting for 73%, 69%, and 65% of all injuries sustained in World War II, Korea, and Vietnam, respectively (Fig. 100–1).² Factors that complicate the comparison of current blast injuries with those seen in other conflicts include advances in Kevlar body armor, helmet technology, and other protective equipment, as well as improved acute trauma care, such that injured personnel survive injuries that would likely have proven fatal in prior conflicts.⁴

According to data from the Defense and Veterans Brain Injury Center (DVBIC), 313,816 military personnel sustained a TBI between the years 2000 and 2014.⁵ Of these TBIs, 83% were classified as mild, 8% moderate, and 1% severe in initial severity (Fig. 100–2).

Most research studies utilizing extant administrative databases likely underestimate the actual numbers of military personnel who sustain TBI for a variety of reasons. First, mild TBI (mTBI), the mildest severity of closed-head injury, may be difficult to diagnose, as overt signs are not always apparent. While a formal TBI screening program was implemented in the VA system in April 2007, and the VA reached out to as many OEF/OIF veterans who had entered the VA system before then, this retrospective approach to screening may have underestimated the number of mTBIs.⁶ Second, approximately 46% of veterans who are eligible for VA care (which includes all OEF/OIF veterans for 5 years after leaving military service) do not elect to receive care within the VA’s health care system.⁷

In 2012, 6.8% of all OEF/OIF/OND veterans receiving care from the VA (approximately 35,826 men and women) were diagnosed with TBI. On average, veterans of OIF/OEF with TBI tend to be younger than their non-TBI counterparts (31 years old, as opposed to 34 years old). A total of 95% of all veterans diagnosed with TBI are male, which is also higher than the proportion of men in the overall veteran population (87%).⁷ Limited data exist in the literature identifying the incidence and prevalence of TBI in older veterans, as well as the incidence of recurrent TBI in veterans who initially sustained TBI during active duty. Civilian studies demonstrate that risk of recurrent TBI is significantly increased after even one prior instance of TBI.⁸ While it is unclear whether the initial TBI actually increases the risk itself, or if the characteristics of individuals who sustain TBI put TBI survivors at higher risk for recurrent TBI, the increased risk exists and must be considered. A current study of recurrent TBI in the veteran population is underway and will provide information to consider for the long-term costs of care, including within the VA.

With regard to cost, Taylor (2014) revealed that the cost of care at the VA for veterans with TBI ($5,831/year/veteran) is nearly four times the cost of non-TBI-diagnosed veterans ($1,547/year/veteran).⁹ For veterans with TBI, PTSD, and pain (termed the “polytrauma triad”), the cost can rise to $7,974/year/veteran. In addition to this well-recognized polytrauma triad,¹⁰ other reported comorbidities associated with blast trauma (Box 100–3) and TBI in military personnel include amputation,¹¹ suicidal ideation,¹² dementia,¹³ insomnia,¹⁴ visual impairment,¹⁵ and auditory and vestibular dysfunction.¹⁶ This in turn has led to unique challenges faced by service members and veterans as they rehabilitate from their injuries.

Blast-Related TBI (bTBI)

Blast-related TBI (bTBI) is comprised of four distinct components: primary, secondary, tertiary, and quaternary (Table 100–1).^17,18 The primary blast injury is caused by the blast wave–induced atmospheric pressure changes. Secondary blast injury is caused by projectiles penetrating the skull and brain. Tertiary blast injury is caused by the acceleration and deceleration of an individual set in motion by a blast and then stopped by a stationary object. Quaternary blast injury is caused by thermal and toxic detonation products that injure the head, face, scalp, and respiratory tract. Unlike primary blast injury, the mechanisms of injury associated with the secondary, tertiary, and quaternary blast injury types are well understood and appear to be similar to closed TBI, penetrating TBI, or anoxia-associated brain injury.¹⁹

The exact mechanism of injury by a primary blast wave is not completely understood. There is a shock and pressure wave that causes a fast change in atmospheric pressure (overpressure followed by an underpressure that is relatively prolonged). When this underpressure is greater than the tissue’s tensile strength, cavitation occurs.²⁰ Experimental animal models that focused on damage related to the compression and dilation changes in energy, or the primary blast wave, tend to support resultant cavitation changes in brain tissue.^21,22 Further model testing demonstrates that shear from the blast wave also may lead to injury and that the spatial distribution of damage from the primary blast wave is independent of the blast direction.²³ Variability of spatial distribution associated with a primary blast wave makes protecting troops from the primary blast wave with protective devices (i.e., helmets) problematic.

Note that bTBI is classified similarly to closed TBI (Table 100–2). A Glasgow Coma Scale (GCS) score of 13 to 15, loss of consciousness (LOC) of less than 30 minutes, and posttraumatic amnesia (PTA) of less than 24 hours are associated with mTBI. Moderate TBI is characterized by GCS of 9 to 12, LOC of 30 minutes to 24 hours, and PTA of 1 to 7 days. Severe TBI is associated with GCS 3 to 8, LOC greater than 1 day, and PTA for greater than 1 week.²⁴ In-field management of bTBI is dictated by initial GCS.

The Guidelines for Field Management of Combat-Related Head Trauma detail appropriate triage for medics in the battlefield after initial management and stabilization have occurred.²⁵ Individuals with blast exposure and GCS of 13 or less are emergently evacuated to a higher level of care. A detailed clinical assessment must occur when the injured service member is seen at the combat support hospital to quantify all injuries, as improvised explosive device (IED) blasts often result in a multitude of injuries. Neuroimaging with computerized tomography (CT) scan is done immediately to assess for skull fractures, edema, or intracranial hemorrhages. Typically, airway protection, mechanical ventilation, intracranial pressure monitoring, and neurosurgical intervention are required in these cases within an intensive care unit (ICU) setting.¹⁹

Moderate-to-severe bTBI is often associated with significant cerebral edema and numerous vascular injuries. This has led to more aggressive management and evaluation of patients. For example, early decompressive craniectomy (shown in Fig. 100–3) has been commonly employed.^26,27 Craniectomy is used to treat increased intracranial pressures and gross brain edema; it also allows any wound debridement, dural repair, ventriculostomies, and evacuation of hematomas. Craniectomy also allows patients to be more medically safe when transported by air, as intracranial pressure is otherwise difficult to manage in flight. After sufficient time for healing of the cerebral edema and increased intracranial pressure (typically more than 6 weeks postcraniectomy), patients are assessed for cranioplasty. Computer-generated cranial prosthetic grafts are typically used for skull reconstruction, as autologous skull reconstruction is usually not feasible.¹⁹ Flap placement has risks of extra-axial fluid collection, seizures, and abnormal contours.²⁸ Ecker et al (2011) showed that 60% of individuals undergoing in-theater bilateral or bicompartmental craniectomy achieved independent living in 2 years, despite low initial GCS.²⁹

Vascular injuries are common after severe bTBI.³⁰ In a study of 187 military personnel with closed or penetrating TBI, there was a 34% prevalence of vascular injury.³¹ Various injuries include traumatic pseudoaneurysm, dissections, and fistulae. There is a high correlation between intracranial aneurysm and vasospasm; vasospasm has been noted to occur over an average time frame of 14 days, but it can occur up to 1 month after the initial injury.³² Monitoring includes transcranial Doppler, and management includes vasodilators or an endovascular procedure, such as stenting or coiling.³⁰ Due to the high prevalence of vascular injury with bTBI, aggressive vascular screening is common, including computerized tomography angiography (CTA).³²

Additional intracranial complications associated with moderate and severe bTBI in the acute setting include complex craniofacial fractures, meningitis, venous thromboembolism, and cerebrospinal fluid (CSF) leakage.³³ Due to the comprehensive system of care developed, there have been substantially improved outcomes in patients with severe injuries.¹⁷

Mild TBI

In-theater diagnosis of mild TBI (mTBI) is difficult. Traditionally, diagnosis was based on self-report. Symptoms however, have been underreported in theater, thus allowing individuals to remain with their unit.¹⁹ As a result, the current protocol requires medical evaluation and mandated screening for all service members associated with blast exposure as soon as possible after the incident. The Military Acute Concussion Evaluation (MACE), which includes patient history and a validated concussion screening measure known as the Standardized Assessment of Concussion (SAC), is used as a screening tool.^34,35 Accuracy of the MACE decreases over time; it is most reliable when given within 12 hours of the blast-related event.³⁶

Positive screening for TBI leads to the patient’s removal from combat until all symptoms have resolved.³⁷ Symptoms typically include headache, fatigue, sensitivity to sound and light, poor concentration, altered balance, dizziness, and dyssomnia (Box 100–4).³⁸ Management of mTBI includes relative (brief) rest, acute symptom management (i.e., headache management) and, most important, education about the injury and expected recovery.³⁹ When symptoms resolve, the service member performs exertional testing to rule out any refractory issues. If all symptoms have resolved after exertional testing, the service member may return to duty; persistent symptoms require additional rest or evacuation to a higher level of care.²⁴

Service members returning from deployment undergo additional screening with the Post-Deployment Health Assessment (PDHA) to identify individuals in need of further clinical evaluation. This evaluation is conducted in designated TBI centers in the military health system that offer multidisciplinary care.⁴⁰ Service members transitioning to VA also will be screened for TBI using the TBI Clinical Reminder. Positive screening initiates additional workup and care through designated TBI clinics within the VA’s Polytrauma System of Care (PSC).

Avoidance of Second Impact Syndrome (SIS), a phenomenon that occurs when a second head injury is sustained prior to complete healing of an initial TBI, can lead to worse clinical outcomes.^41,42 Multiple TBI exposure may place individuals at risk for developing chronic traumatic encephalopathy (CTE), a progressive, tau-protein-linked neurodegenerative disease associated with multiple concussions in athletes.⁴³ Recent review in a postmortem case study of human brains subjected to blast-related TBI showed evidence of CTE; further, animal models with multiple blast-related injuries exhibited CTE-type neuropathology.⁴⁴ However, research examining the relationship between blast-related TBI and CTE is limited—primarily as both conditions are underdiagnosed.

Multisensory Impairments

Blast-related head and neck injuries are associated with dysfunction in multiple sensory systems that can be related to central nervous system (CNS) and peripheral nervous system (PNS) pathology. In individuals with blast-related TBI, Lew et al (2011) noted a correlation between visual and auditory dysfunction, termed “dual sensory impairment (DSI).”⁴⁵ Pogoda et al (2012) examined the cooccurrence of impairment in auditory, vestibular, and visual dysfunction, termed “multisensory impairment (MSI),” and found a higher incidence of MSI with deployment-related mTBI.⁴⁶

Visual symptoms are a common complaint in veterans diagnosed with mTBI from the OEF/OIF conflicts; multiple sources have cited reports of up to 75% of these individuals suffering symptoms of visual disturbance.^47,48 LOC has been significantly associated with the severity of reported visual symptoms, which include blurred vision, photosensitivity, and accommodative issues.⁴⁹ Evidence points to static and dynamic vergence dysfunction, specifically delayed responses, restricted near-vergence ranges, and reduced near-point convergence as common clinical findings on screening examination.⁵⁰

Blast-related ear injuries and hearing impairment are common during deployment. Dougherty et al (2013) noted a prevalence of ear injury of 31% with the most common diagnoses, including tympanic membrane rupture and tinnitus associated with inner-ear injury.⁵¹ Also, blast-related TBI was associated with greater self-reporting of tinnitus and hearing loss compared to nonblast-related TBI.⁵² Blast-related trauma can injure both the peripheral and central auditory nervous systems, which have overlapping functions, causing difficulty with evaluation, diagnosis, and treatment.⁵³ Oleksiak et al (2012) found that only one-third of patients with auditory impairment found on higher-level testing were found to have abnormalities via audiogram, indicating that individuals with TBI and audiologic symptoms should be considered for advanced testing beyond audiography.⁵⁴ Vestibular dysfunction (specifically, poor balance and dizziness) is commonly reported as persistent symptoms following blast exposure and likely has components of both PNS and CNS affected. Research focused on the central mechanisms of vestibular dysfunction is currently lacking.⁵⁵

Wounds, Amputation, and Orthopedic Injuries

The use of IEDs has resulted in a multitude of other injuries. A review of musculoskeletal wounds and casualties in the U.S. Army Brigade Combat Team in OIF note that 81% of musculoskeletal combat casualties were due to explosions; that spine, pelvis, and long-bone fractures comprised 56% of the total fractures sustained in combat; and that the musculoskeletal combat casualty wound incidence rate per 1,000 combat-years of open fracture was 5.0, closed fracture was 6.4, and soft-tissue or neurovascular injury was 32.8.⁵⁶ A study of combat-specific personnel (cavalry scouts) showed an injury to one or more musculoskeletal systems in 67% of individuals; 69% of these injuries were associated with blasts. Of these injuries, 46% of all injuries involved the lower extremities; tibial fractures (8%) were the most common injury encountered; and amputations comprised 11% of all wounds.⁵⁷ Belmont et al (2013) noted that amputations represented 6% of all combat wounds and nearly all traumatic amputations were caused by explosive blasts.⁵⁸ A survey of individuals with traumatic limb loss from combat from the OEF/OEF conflict noted a 76% prevalence of phantom limb pain, 58% of prosthesis-related skin problems, and 62.9% of residual limb pain.⁵⁹ Of note, 85.5% of individuals who responded to the survey rated their health status as excellent, very good, or good. In a study of 274 OEF/OIF service members who sustained burn injuries, 52% were associated with explosions in hostile areas, the mortality rate was 4%, there was a 26% rate of inhalation injury, and the hands and face were the most frequent locations of burn injuries.⁶⁰ Eskridge et al (2012) performed a retrospective review of all OEF/OIF injuries associated with explosion and found that the extremities were the most commonly injured body region, and that surface injuries (e.g., burns, contusions, open wounds, and abrasions) were the most frequent type.⁶¹

Chronic Pain

There is a high cooccurrence of TBI and chronic pain among OEF/OIF service members.⁶² Gironda et al (2009) found that 47% of OEF/OIF individuals using the VA system presented initially with pain, and of these individuals, 60% presented with moderate-to-severe pain.⁶³ In another study, 88% of individuals with blast-related polytrauma reported persistent pain postdeployment.⁶⁴ In a review of the medical records of 340 OEF/OIF veterans, Lew et al (2009) described the polytrauma triad (i.e., TBI, PTSD, and pain) and noted 82% of the cases involved chronic pain (back 58%, head 55%), 68% PTSD, and 67% TBI with persistent postconcussive symptoms (Fig. 100–4). The frequency of pain in the entire triad was 42%.⁶⁵ It should be noted that this study involved a group of OIF/OEF veterans who had screened positive to all four questions of the TBI questionnaire administered by the Veterans Health Administration (VHA). In a follow-up study, Cifu et al (2013) analyzed data from a large group of veterans (N = 613,391), regardless of their responses to the TBI screening questions, and found that only 6.0% of this population expressed the full polytrauma triad.¹⁰ Despite the difference in percentages, the study’s results also revealed that the majority of patients with TBI also had a mental health disorder, and roughly half suffered from both PTSD and pain.¹⁰