REHABILITATION OF POLYTRAUMA PATIENTS REQUIRES a thorough understanding of how these injuries occur, which is important for appropriate and timely management. Polytrauma is defined as injury to at least two or more body regions that lead to “physical, cognitive, psychological, or psychosocial impairments and functional disability.”¹ Polytrauma typically affects the young and middle-age groups or service members in the military. The combination of multiple injuries occurring as a result of the same traumatic event often lead to other disabling medical and psychological conditions including, most commonly, traumatic brain injury (TBI), amputation, orthopedic injuries, spinal cord injury, post-traumatic stress disorder, or other mental health impairments. Management of polytrauma patients is challenging and requires utmost utilization of resources for their care. Specialized coordinated care from multiple sources working together is needed. A comprehensive interdisciplinary team is often assembled in executing patients’ transition from acute hospitalization to acute rehabilitation and finally to help integrate them into the outpatient setting.

Background

Literature regarding the topic of polytrauma is overtly expansive and spans decades. When narrowing the review parameters, it is noted that there are over 2,000 articles published within the last 5 years and another 400 plus written within the last 12 months. Publications include (but are not limited to) meta-analysis, case reports, and funded studies. Within the subset of publications evaluated, a variety of treatment methods have been implemented and outcomes measured. The overarching focus of the literature underlines the definition and recognition of polytrauma/TBI as a “chronic health condition with residual medical, functional, and psychosocial issues.”²

Since the early twentieth century, medical practitioners have recognized the need for comprehensive treatment plans geared toward maximizing function in individuals who have endured an appreciable decline in overall quality of life due to polytrauma. Those returning from combat were the most affected. Many soldiers died from their wounds while those who survived endured lifelong complications. During World War I, “clusters of physical and psychological symptoms that occurred as a result of exposure to intense combat [were] labeled in various ways, from ‘hysteria’ to ‘shell shock’ to ‘polytrauma’.”³ During World War II, “terms such as battle fatigue, combat stress, combat exhaustion, and war neuroses emerged to describe similar symptoms, which became a significant concern to military command of the U.S. Armed Forces.”³ Given the substantial morbidity and mortality, it was obvious that a standardized methodology for management of these conditions and their sequela needed to be developed; however, the ability to share information including research and clinical practices was severely limited.

Rehabilitation as a medical practice remained a relatively foreign concept despite the promotional efforts of doctors, nurses, and therapists caring for these polytrauma patients. It was not until the 1970s that perceptions and access to rehabilitative care began to emerge due to a noticeable number of patients surviving their injuries following advances in emergency and acute care medicine. These patients were admitted/transferred to what was ultimately referred to as “rehabilitation” facilities that specialized in polytrauma. Rehabilitation had been “discovered” and various institutions related to polytrauma care and research were established soon thereafter.⁴ “In the United States, the realization grew that rehabilitation for these injuries was possible and might have a significant impact on quality of life and the social and financial burden to family and society.”⁴ This thought process ultimately ushered in and influenced the development of what we now know as Model System Care Programs.

The first model systems were built to demonstrate and evaluate the costs and benefits of a comprehensive service delivery system for individuals with TBI/polytrauma. Additionally, the model systems focused on establishing research programs to conduct innovative analyses, categorize and assess improvements in management of TBI/polytrauma care and rehabilitation, and participate in widespread studies, thereby contributing to a national database.⁴ The growth and development of model systems as a means of guiding treatment protocols and delineating parameters for research provided a hub of “information sharing” that could be utilized and accessed by multiple disciplines. Model systems established foundational parameters that ensured baseline clinical understanding without compromising an individual’s ability to explore different treatment alternatives. Moreover, model systems allowed various medical institutions to collect data from other participating locations and compare outcomes. This participation allowed programs to continually reshape and define the needs of the polytrauma population and convert these findings into policy, which created an environment for continuous quality improvement.²

It is essential to note, in recognition of rehabilitation medicine’s history, the importance of collaboration with the Department of Veterans Affairs (VA) in instituting Model System programs. The VA continues to promote significant advances in rehabilitation medicine because of its unique clinical environment most notable for polytrauma associated with combat. Data collected across military and civilian disciplines is used not only for comparative purposes but can also assist in the development of evidence-informed policy that is applicable to both populations.⁵

The field of epidemiology aims to identify the incidence, prevalence, and impact of disease in large populations. Epidemiological findings consequently affect disease prevention and management strategies. Both globally and in the United States, trauma is the leading cause of morbidity and mortality for those aged 15 to 44.⁶ The burden of traumatic injuries has substantial economic and social costs. There are a variety of mechanisms through which trauma is sustained. Motor vehicle crashes, occupational accidents, terrorism, violence, falls, use of firearms, and warfare are common etiologies of injury. Traumatic injuries are projected to be a leading cause of death and disability as the developing world industrializes, motor vehicle transport becomes more commonplace, and armed conflicts emerge.⁷ Globally, in the year 2000, approximately 5.8 million people died from trauma with the incidence projected to increase to 8.4 million deaths by 2020.⁸

While there is no universally accepted definition of polytrauma, there is general consensus that this term applies to severe injuries affecting two or more body regions. Multiple trauma is reported in 15% to 20% and approximately 10% of the overall trauma data in the United States and the United Kingdom, respectively.⁹ A prospective international study in 2013 failed to demonstrate agreement on the criteria for polytrauma based on subjective assessments by trauma surgeons.¹⁰ The injury severity score (ISS) is a trauma scoring system that defines injury severity based on nine anatomic regions with scores ranging from 1 to 75.¹¹ The areas of the head, face, neck, thorax, abdomen/pelvis, spine, upper extremities, lower extremities, and external skin are rated in degree from 0 to 6. Severe injury is associated with an ISS >15. There are a number of trauma scales which are employed to characterize the degree and type of injury, in addition to survival probability (Table 90–1).

Data from the National Trauma Data Bank Annual Report in 2007 demonstrated that of the 1,485,098 studied cases in the United States between 2002 and 2006, 12.8% had severe injuries with ISS of 16 to 24 while 9.6% had very severe injuries with ISS >24.⁹ The largest source of injuries was motor vehicle accidents at 37.9% followed by falls at 30.2%. There was an overwhelming gender predisposition with males sustaining 65% of all traumatic injuries. The largest peak was in the 16 to 44 age group with injuries related to motor vehicles and firearms. Blunt trauma was involved in 86.2% of cases with penetrating injury comprising 11.1%. Predictors of mortality included thoracic and abdominal injuries with >10% mortality, brain and skull injuries with 7.8% mortality, and age >65 with 42% mortality.

In continental Europe, the annual death toll and rate of severe injury (ISS >15) varies from 25/100,000 in Germany to 52.2/100,000 in Italy.¹² Across England and Wales, 16,000 people die annually from injury.¹³ Data from Spain and the Netherlands show that injury accounts for larger health care expenditures than cancer or cardiovascular disease.^14,15 As with US data, injury is most common in younger males, with motor vehicle collisions being the primary cause of death and severe injury.¹⁶ Data from the Trauma Audit and Research Network in the United Kingdom demonstrates that risk factors for morbidity and mortality remain consistent with US trends. The mortality rate more than doubles after age 65, regardless of gender. In the 16 to 65 age distribution, 18.5% of trauma cases fall under the category of polytrauma while only 11.5% can be designated as such in those over age 65.¹³ Polytrauma associated with abdominal injury confers an overall mortality rate of 36.3% while associated thoracic injury has a 29.6% overall risk of death.¹³ Polytrauma coupled with head injury results in a 32.4% death rate.

Both in the United States and internationally, the disease burden of traumatic injuries impacts health care expenditures and societal quality of life measures. Unfortunately, the public health burden of injury is expected to increase in the coming years. Managing this global pandemic requires continued optimization of post trauma care while fostering efforts to reduce high-risk activities.

Polytrauma has been thought of as a syndrome of combined injuries with an ISS >17 and 1 day of SIRS leading to dysfunction of remote organs not directly injured at the time of the trauma.¹⁷ When expanding the definition of polytrauma to include traumatic brain injury plus another injury or trauma, the mechanisms of head injury comes into consideration.¹⁸ Primary brain injuries include initial contusion/laceration, and blunt or penetrating trauma. Secondary injuries with hypotension, inflammatory cascade induction, hypoxia, and host defense failure are responsible for the later morbidity and mortality.¹⁹

The “two-hit” theory explains the first “hit” as the trauma to the primary organ which causes local tissue damage and starts the inflammatory response. Secondary “hits” include respiratory distress, cardiovascular instability, metabolic acidosis, ischemia/re-perfusion injuries, and infection.²⁰ Systemic inflammation was defined in 1991 by the American College of Chest Physicians/Society of Critical Care Medicine (ACCP/SCCM) as systemic inflammatory response syndrome (SIRS). Two out of four clinical parameters must be met to be diagnosed. Sepsis is SIRS plus bacteremia or bacterial focus. SIRS is characterized by local and systemic production of inflammatory cytokines, complements, proteins, coagulation pathways, and neuro-endocrine factors.²¹ The highest incidence of SIRS occurs after isolated or combined severe head injury.²² The body’s anti-inflammatory mediators seem to be responsible for organ dysfunction and increased susceptibility to infection. The systemic inflammation is then augmented by second “hits” from ischemia, surgical interventions, and infection. There appears to be an imbalance of immune responses with a large release of pro or anti-inflammatory mediators. Endothelial damage, disseminated intravascular coagulation, and accumulation of leukocytes lead to apoptosis and necrosis of parenchymal cells (Fig. 90–1).²³

Regarding head trauma, the blood brain barrier integrity may become compromised leading to a bidirectional communication of the inflammatory cascade.²⁴ Primary epidural hematomas or cerebral edema can lead to a cerebral compartment syndrome and, without intervention, can be deadly.²⁵

Blast injuries, such as those caused by an improvised explosive device (IED), have the potential to inflict catastrophic multiple and severe injuries that only a few US health care providers outside the military and Veterans Administration have experience. The mechanism of injury usually dictates the pattern of trauma and complications such as air embolism, rhabdomyolysis, burns, renal failure, seizures, hemorrhages, elevated intracranial pressure, and meningitis can occur.