Physiotherapy for Whiplash: Managing Psychosocial Factors

Introduction and Background

The term "whiplash" was coined in 1928 by H. D. Crowe and remains the only diagnosis that relates to causation rather than to the tissue damage involved in a traumatic injury (Wallace & Wallace, 2003). Although a number of traumatic events can result in whiplash — such as those experienced in contact sports like football (Varney & Roberts, 1999) — perhaps the most common type, and the one best understood by the general public, involves vehicular accidents in which one vehicle is struck from the rear by another. Fritz (1999) notes that the National Safety Council reports that fully 85 percent of all neck injuries experienced by Americans are caused by rear-end automobile collisions, due in large part to improperly designed neck restraints that may be as far as six inches from most drivers' necks. As Fritz explains, "Since the head must travel so far, it strikes the restraint with enough force to tear ligaments or rupture spinal discs. Ideally, the restraint should be an inch from the head and be contoured to fit the neck" (1999:32).

Wallace and Wallace note that "a whiplash injury occurs when a car driver or passenger is rear-ended. The head and neck stay still at first, while the body jerks forward. As the body returns back, the neck hyperextends backward" (2003:10). By contrast, Albertine reports that the term "whiplash" typically refers to neck injuries only: "Whiplash is a term often applied to trauma of the cervical spine and tissues caused by rapid movement of the head and forceful flexion of the neck causing pain, muscle spasms and limited motion" (2003:760). Jensen, Kasch, Bach, Bendix, and Kongsted provide the following definition: "Whiplash trauma is caused by an acceleration-deceleration force transferring its energy to the cervical spine. Whiplash-associated disorder (WAD) refers to the symptoms that develop after a whiplash injury" (2010:1812).

According to Fabiano and Daugherty (2004), whiplash is a type of traumatic injury that may or may not also involve damage to the brain; in any event, the term "traumatic brain injury" includes a wide range of conditions that can result from an external mechanical force causing some degree of damage to brain tissue. Poorbaugh and colleagues (2008) report that "whiplash" typically refers to injuries that involve both the neck and head: "The term 'whiplash' represents the multiple factors associated with the event, injury, and clinical syndrome that are the end-result of a sudden acceleration-deceleration trauma to the head and neck. However, contentions surround the nature of soft-tissue injuries that occur with most motor vehicle accidents and whether these injuries are significant enough to result in chronic pain and limitations" (2008:65).

The term "mild traumatic brain injury" is used to describe head trauma that does not involve loss of consciousness, or involves a temporary loss of consciousness persisting fewer than 20 minutes (Fabiano & Daugherty, 2004). The term "post-concussional syndrome" is also used synonymously with "mild traumatic brain injury," with both terms describing the broad range of psychosocial, cognitive, and behavioral manifestations associated with traumatic brain injuries (Fabiano & Daugherty, 2004). While the overall incidence of traumatic brain injuries involving whiplash remains largely conjectural, it is estimated that between 7 and 10 million new cases of traumatic brain injury occur annually in the United States alone (Fabiano & Daugherty, 2004).

Whiplash injuries remain a highly debated clinical entity (Poorbaugh, Brismee, Phelps & Sizer, 2008; Davidson & Tung, 2008; Walker & Hefner, 2006; Morris, 2000), but the effects of these injuries represent a substantial public healthcare issue with important socioeconomic implications (Block, Kremer & Fernandez, 1999). Rasmussen and colleagues recently emphasized that "the sequelae following whiplash injuries entail considerable human costs and expenses for both treatment and social services, especially public income benefits" (2010:1815). There also remains a dearth of timely and relevant studies concerning both the effects of whiplash and efficacious treatments, with much of the literature being anecdotal in nature, some authorities doubting the legitimacy of the diagnosis and subsequent disabled conditions altogether, while yet other researchers merely repeat what previous authorities have reported. Rasmussen et al. identify three pressing research needs:

1. To identify evidence-based prophylaxis and treatment;
2. To monitor medical diagnoses in relation to social benefits in order to support research opportunities; and
3. To assess whether other social solutions comprise alternatives superior to current treatment and compensation options (Rasmussen et al., 2010:1815).

There have been a few on-point studies to date, though even these report mixed findings. Rebbeck, Refshauge, and Maher reported that "health outcomes for whiplash are poor, with over 60% of whiplash sufferers unrecovered after the acute phase (3 months) of their injury" (2006:442). Michaleff, Maher, Jull, Latimer, Connelly, Lin, Rebbeck, and Sterling place the rates even higher and recovery periods longer: "Whiplash is the most common injury following a motor vehicle accident. Approximately 60% of people suffer persistent pain and disability six months post injury" (p. 149). By contrast, Jensen and colleagues note that "the prognosis is favorable with recovery in over 90% of the injured subjects. In a fraction of patients, long-term symptoms with pain and cognitive and emotional symptoms may occur, causing long-term disability" (2010:1812). Jensen et al. add that for this smaller percentage with long-term symptoms, "the pathophysiology is unclear. Most research groups favor a multifactorial pathophysiology similar to that observed for other chronic pain conditions without a clear nociceptive or neuropathic component" (2010:1812). According to Sterling and Pedler, however, there may in fact be a neuropathic component: "Whiplash is a heterogeneous condition with some individuals showing features suggestive of neuropathic pain. A predominantly neuropathic pain component is related to a complex presentation of higher pain/disability and sensory hypersensitivity" (2009:173).

The results of a long-term study by Rooker, Bannister, Amirfeyz, Squires, Gargan, and Bannister — which reviewed 22 patients at a mean of 30 years following a whiplash injury — showed that many victims continue to experience the effects of their injuries long after the event. The authors reported: "A complete recovery had been made in ten (45.5%) while one continued to describe severe symptoms. Persistent disability was associated with psychological distress but both improved in the period between 15 and 30 years after injury. After 30 years, ten patients (45.5%) were more disabled by knee than by neck pain" (Rooker et al., 2010:835).

A cross-sectional study by Hincapie, Cassidy, Côte, Carroll, and Guzman used a population-based cohort of 6,481 residents in Saskatchewan, Canada who had experienced whiplash injuries and were subsequently treated or had filed insurance claims. The researchers analyzed the prevalence of pain in 13 different body areas and found that "irrespective of pain in other areas, 86% of respondents reported posterior neck pain, 72% indicated head pain, and 60% noted lumbar back pain. Ninety-five percent of claimants reported some pain within the posterior trunk region, comprising the posterior neck, shoulder, mid-back, lumbar, and buttock areas" (Hincapie et al., 2010:434). Just 0.4% of study subjects had only posterior neck pain. Their findings yielded four primary patterns representing 60% of the variance in pain localization:

1. Upper anterior trunk and upper extremity pain;
2. Head, posterior neck, and upper posterior trunk pain;
3. Low back pain; and
4. Lower anterior trunk and lower extremity pain.

Hincapie and colleagues concluded that "pain after traffic injury is most commonly reported in multiple body areas; isolated neck pain is extremely rare" (2010:435).

A population-based study by Crutebo, Nilsson, Skillgate, and Holm further substantiates the legitimacy of the whiplash condition. These authors report that "the most common symptoms at baseline after neck pain were reduced cervical range of motion (in 83.9% of men, 82.2% of women), headache (61.0% and 69.3%, respectively), and low back pain (35.9% and 36.1%)" (2010:1527). The findings of a study by Vincent confirm that many whiplash victims suffer from headaches, some of migrainous intensity. Vincent describes cervicogenic headache (CEH) as "a well-recognized syndrome," noting that "whiplash-related headaches tend to be short-lasting, admitting mostly a tension-type headache or a CEH-like phenotype" (2010:238–239).

Although comparable symptoms were found in both sexes in the Crutebo et al. study, significant gender-related differences were also identified in the literature. Males account for 65–75% of mild traumatic brain injuries with or without whiplash (Fabiano & Daugherty, 2004). However, Block and colleagues report that "women appear to experience whiplash injuries more often than do men" (1999:239), attributing this to the slimmer necks most women have, which are characterized by less musculature and are therefore less able to resist acceleration forces during vehicular impacts. Block et al. also note that "other possible reasons for the gender difference are that women may be more likely to seek medical attention, be sent to medical specialists for complaints of pain, respond to their injuries in a way that aggravates their condition, or be subjected to more external stressors making it more difficult for them to cope" (1999:239). Further studies are needed to help establish these gender-related differences with greater precision (Block et al., 1999).

Physical and Biosocial Effects of Whiplash Injury

One of the most perplexing aspects of whiplash injuries is that victims may remain unaware of even a significant injury until several hours have elapsed after a vehicular accident. Block et al. emphasize that "most patients feel little or no pain for the first few minutes following injury after which symptoms gradually intensify over the next few days" (1999:239). According to Block and colleagues, "in the first few hours, findings on examination are generally minimal. After several hours, limitation of neck motion, tightness, muscle spasm, and/or swelling and tenderness of both anterior and posterior cervical structures become apparent. This delay is likely due to the time required for traumatic edema and hemorrhage to occur in injured soft tissues" (1999:239).

There are a number of commonalities in the types of injuries and complaints that many whiplash victims experience. Block et al. note that "patients with whiplash injuries invariably complain of an achy discomfort in the posterior cervical region radiating out over the trapezius muscle and shoulders, down to the interscapular region, up to the occiput, and/or down the arms" (1999:239). According to Sterling (2004), although there are important differences in the types of physical and psychological impairments that occur in whiplash victims who completely recover versus those who develop persistent pain, there are commonalities as well: "Motor dysfunction, local cervical mechanical hyperalgesia and psychological distress are present soon after injury in all whiplash injured persons irrespective of recovery" (2004:60). Those who develop persistent moderate-to-severe pain show "a more complex picture, characterized by additional impairments of widespread sensory hypersensitivity indicative of underlying disturbances in central pain processing as well as acute posttraumatic stress reaction, with these changes present from soon after injury" (Sterling, 2004:60).

Poorbaugh and colleagues note that "considering that 14% to 42% of patients are left with chronic symptoms following whiplash injury, it is unlikely that only minor self-limiting injuries result from the typical rear-end impact. As psychosocial issues play a role in the development of persistent whiplash symptoms, discerning the organic conditions from the biopsychosocial factors remains a challenge to clinicians" (2008:66).

Many whiplash victims experience headaches following a whiplash episode. Block et al. note that "headache is a common symptom following whiplash injury. Within 24 hours of the accident, many patients complain of diffuse neck and head pain. The headache may be limited to the occipital area or may spread to the vertex, temporal-frontal, and retro-orbital areas" (1999:239). Van Suijlekom, Mekhail, Patel, Van Zundert, van Kleef, and Patijn similarly report that "whiplash-associated disorders are comprised of a range of symptoms of which neck complaints and headaches are the most significant spine-related" findings (2010:131). The pain associated with these headaches "may be a dull pressure or a squeezing sensation and include pounding and throbbing (migrainous) components. Muscle contraction and vascular headaches often are present simultaneously (posttraumatic mixed headache)" (Block et al., 1999:239). According to Binder, if fractures and neurological effects are excluded, "nonspecific (simple) neck pain is the commonest cause of neck symptoms and results from postural and mechanical causes. It includes pain following whiplash injury provided there is no bony injury or objective neurological deficit" (2007:79).

Many whiplash victims also experience depressive episodes. According to Phillips, Carroll, and Cote, "depression is common in whiplash-associated disorders. Predictors of persistent depression included older age, greater initial neck and low back pain, post-crash dizziness, vision and hearing problems, numbness/tingling in arms/hands, anxiety, prior mental health problems, and poorer general health" (2010:945). Phillips and colleagues emphasize that "recognition of these underlying risk factors may assist health care providers to predict the course of psychological reactions and to provide effective interventions" (2010:946). Whiplash injuries can also cause hoarseness and voice fatigue (Heman-Ackah, Sataloff, Corlin, Hawkshaw & Divi, 2008).

A study by Chen and colleagues (2009) examined whiplash injury mechanisms in an effort to develop a better understanding of cervical facet pain. Their analysis found that:

1. Whiplash injuries are generally considered to be a soft tissue injury of the neck with symptoms such as neck pain and stiffness, shoulder weakness, dizziness, headache, and memory loss.
2. Based on kinematical studies using cadavers and volunteers, there are three distinct periods that have the potential to cause injury to the neck. In the first stage, flexural deformation of the neck is observed along with a loss of cervical lordosis; in the second stage, the cervical spine assumes an S-shaped curve as the lower vertebrae begin to extend and gradually cause the upper vertebrae to extend; during the final stage, the entire neck is extended due to extension moments at both ends.
3. The in vivo environment afforded by rodent models of injury offers particular utility for linking mechanics, nociception, and behavioral outcomes. Experimental findings have examined strains across the facet joint as a mechanism of whiplash injury and suggested a capsular strain threshold or vertebral distraction threshold for whiplash-related injury, potentially producing neck pain.
4. Injuries to the facet capsule region of the neck are a major source of post-crash pain. Several hypotheses exist regarding how whiplash-associated injury may occur, with three related to strains within the facet capsule connected with events early in the impact.
5. There are several possible injury criteria to correlate with the duration of symptoms during reconstructions of actual crashes. These results form the biomechanical basis for a hypothesis that the facet joint capsule is a source of neck pain and that the pain may arise from large strains in the joint capsule causing pain receptors to fire (Chen et al., 2009:306).

Poorbaugh and colleagues provide a useful gradation of whiplash-related disorders, summarized in Table 1 below.

Table 1: Grades of Whiplash-Related Disorders

Grade 0: No neck symptoms or physical signs.
Grade 1: Neck pain, stiffness, or tenderness only; no physical signs.
Grade 2: Neck symptoms and musculoskeletal signs.
Grade 3: Neck symptoms and neurological signs.
Grade 4: Neck symptoms and fracture or dislocation.

Source: Poorbaugh et al., 2008:72

Whiplash victims in grades 0 and 1 do not exhibit physical manifestations that are readily discernible to the healthcare provider, a fact that may prevent appropriate medical intervention. Chen, Yang, and Wang emphasize that "despite a large number of rear-end collisions on the road and a high frequency of whiplash injuries reported, the mechanism of whiplash injuries is not completely understood. One of the reasons is that the injury is not necessarily accompanied by obvious tissue damage detectable by X-ray or MRI" (2009:305). By sharp contrast, it is unlikely that any healthcare practitioner would dispute the legitimacy of a grade 4 whiplash-related disorder wherein a fracture or dislocation is readily apparent. Within and between these several grades of whiplash injuries, there exist a number of grey areas that make the formulation of appropriate treatment plans all the more challenging.