Approximately 50% of people injured in a motor vehicle collision will never fully recover, 25% develop persistent moderate/severe pain and disability and 25% experience milder levels of disability.  Being able to differentiate individuals who are likely to recover from those that are not may help direct the most appropriate and effective treatments. [1] 

 35 million people are injured or disabled in a motor vehicle crash annually in the United States with a financial impact of $265 billion.[2]  90% of all motor vehicles at speed less than 14 mph and it is in these that whiplash injuries occur.  Injury and disability from a car crash have less to do with the degree of vehicle damage and more to do with human factors and change of velocity of the head and upper torso.  The most common mechanism of whiplash injury is from a rear-end collision.  A summary of the literature on human crash test has demonstrated that a change in velocity of 2.5 mph was sufficient enough to cause symptoms and 8.7 mph was needed to cause damage to a vehicle. 

 The number of people being injured in a motor vehicle collision annually are on the rise, and the majority of these are collisions that happen at lower speeds which produce the majorities of the whiplash-associated injuries.  The most common symptoms following a whiplash related injury included: neck pain, stiffness, headaches, back pain, headache, paresthesia, and neurological deficit.  These are among the most common symptoms patients seek chiropractic care for.  Many family practitioners and an urgent care center won’t event treat people injured in a car crash.  Emergency Centers typically ensure the patient is stable and release them without additional treatments.  Chiropractors are typically the most qualified professional to treat patients injured in a car crash.  But with a recovery rate of 50%, it’s essential for providers to understand the predictors of poor prognosis. 

“Chiropractors are typically the most qualified professional to treat patients injured in a car crash.”

Three factors that must be considered with any patient with a whiplash related injury are:  Risk factors that increase injury likelihood and severity, factors that complicate care and factors that can predict recovery.

Risk Factors

Risk factors are pre-deposing factors that increase the risk and severity of someone being injured in car crash.  Risk factors included:

·         Being female

·         Head turned on impact

·         Rear-end collision

·         Poor head restraint positioning

·         Unaware of impending crash

·         Loss of cervical lordosis

·         Toe-hitch in rear-end collision

·         Improperly positioned head restraint

Complicating Factors

Complicating factors are pre and post-injury factors that complicate and make recover more challenging.  A list of complicating factors can be found in the International Chiropractic Association’s Best Practices & Practice Guidelines (Chapter 11, Table 7).

Examples of complicating factors included:

·         Advanced age

·         Disc herniation

·         Obesity

·         Prior surgery

·         Metabolic condition

·         Arthritis

·         Prior spine injury

·         Obesity

·         Scoliosis

·         Congenital anomalies

Prognostic Factors

Prognostic factors are factors that can predict recovery vs chronicity.  Although there are many predictors of poor recovery from a whiplash related injury, I’ve picked out eight that are supported by the highest levels of evidence, systematic reviews, and meta-analysis.  Levels of evidence ranges from 7-to-1 with 7 (authority or professional opinion) being the lowest and 1 (systematic reviews or meta-analysis) being the highest. 

8 Predictors of Poor Recovery Following a Motor Vehicle Collision

1.    Initial Pain Intensity (NRS, VAS)

2.    Initial Neck Disability Index (NDI)

3.    Initial WAD Grade of Injury

4.    Initial Cervical Range of Motion

5.    Hyeralgesia (cold, algometer)

6.    Initial Expectations of Recovery

7.    Post-Crash Emotional Factors (e.g. catastrophizing)

8.    Muscle Fatty Infiltration (on MRI)

Initial Pain Intensity 5.5 / 10:  Initial pain intensity is the #1 predictor that a patient will not fully recover to pre-injury status.  Meta-analysis from 8 cohorts have established a cut off of 5.5 / 10, with initial pain above this having a six-fold increase in the risk of persistent pain and/or disability at long-term follow-up.[3-5] 

 Neck Disability Index Above 15 or 30%:  The #2 predictor of poor recovery is initial self-reported NDI of 15 or 30%.  NDI is a 10 question, questioner.  Each question consists of 6 answers graded 0-5. The total points are added up and then divided by 50.  An initial score greater than 30% is a high predictor of poor recovery.[3, 4, 6]

WAD Grade III:  Both the Croft Grading system and the Quebec Task Force (QTF) has a grading system for whiplash-associated disorders.  The Quebec Task Force grading system is almost a mirror image of Croft’s.  For Croft’s grading system a Grade III includes decreased ROM, some ligamentous injury and neurological symptoms.  I personally heard Dr. Croft discusses that his grading system was changed from neurological findings to symptoms. Radicular symptoms included referred pain from facet injuries which are very common in whiplash related injuries. The QTF Grade III WAD includes neck and upper back neurological signs including decreased reflexes, decreased sensation and decreased strength.  Having a WAD grade III increases the odds of being high-risk for poor recovery.[3, 4, 7]

Initial ROM:  Initial decreased active ROM and decreased ROM measured at 3 months is a high predictor of poor recovery.  The clinical outcomes at 2 years can be predicted at 3 months with 76% accuracy in individuals with neck stiffness.[8]  ROM should be measured with DUAL Inclinometer and follow all AMA Guidelines including proper warmup.  Additionally, ROM naturally decreases with age so ROM should be compared normal age-related values.[9, 10]

Hyperalgesia:  Hyperalgesia is an enhanced pain response, frequently caused by an injury. Cold hyperalgesia is a prognostic factor in WAD for long-term pain and disability.  Cold hyperalgesia can be determined by applying an ice cube to the patient’s neck and having him/her rate their pain levels after 10 sec of ice application. Using an ice cube has been found just as effective as using a neurosensory analyzer.  The test is done by simply applying ice to the skin of the cervical paraspinal for 10 sec and repeated 3 times, take the average pain scale.  Any value greater than 5 is a good predictor of cold hyperalgesia and poor recovery.[11-13]

Expectation of Recovery:  When patients are asked to rate their expectation for recover (NRS 0-10) on how likely they are to have a complete recovery with 0 being “not likely” and 10 being “very likely” individuals that rate themselves less likely to have a full recovery are more likely to have a long-term disability compared to individuals that expect to make a full recovery.  The patient’s expectations for recovery are very important in prognosis for recovery.[14]

Initial Emotional State:  Hyperarousal is when a patient’s body suddenly kicks into high alert as a result of thinking about their trauma.  Even though real danger may not be present, their body acts as if it is, causing lasting stress after a traumatic event. Hyperarousal symptoms form 1 of the 3 necessary clusters of symptoms in the diagnosis and presentation of posttraumatic stress disorder (PTSD).[1, 15, 16]

Hyperarousal symptoms:

·         Sleeping problems

·         Difficulties concentrating

·         Irritability

·         Anger and anger outburst

·         Panic

·         Constant anxiety

·         Easily scared or startled

·         Self-destructive behavior (ex. drinking too much)

·         A heavy sense of guilt or shame

Catastrophizing is when someone thinks something is fare worse than it actually is.  Reducing catastrophizing is an important predictor of recovery.  The worse the patient’s initial emotional state the worse the prognosis for a full recovery. Reducing catastrophizing and improving depression are important predictors of recovery.[15, 16]

Muscular Fatty Infiltration (on MRI):  The aging process causes skeletal muscle mass to decreased and is replaced by noncontractile connective tissue.  Due to a reduction in both the number and size of muscle fibers and to some extent caused by the progressive neurogenic process.  The expression of fat cells is the result of an injury-induced inflammatory response.  After an injury, there is an increase in pro-inflammatory cytokines that can stimulate the trans-differentiation into adipose tissue.  There is a significantly greater fatty infiltration in neck extensor muscles, especially in the upper cervical spine, in subjects with persistent WAD when compared to healthy controls.[17] Fatty infiltration in lumbar multifidus muscle is also strongly associated with chronic low back pain.[18]

Time and Chronic Pain:  Expectation of recovery from WAD after 3 months is also greatly reduced.  After 3 months of pain frequently becomes chronic.  Altered central pain modulation is a major pain mechanism in chronic musculoskeletal pain disorders and is associated with poor outcomes.  Central Sensitization (Central Pain Syndrome) is a term used to describe when the pain becomes “engrained” into the central nervous system.  Individuals with central sensitization become very hypersensitive and in a state constant/chronic painful stimuli increasing their pain level and risk of chronicity.[19, 20]

 An understanding of risk factors, complicating factors and prognostic factors are critical in treating patients injured in a motor vehicle collision.  Not only does it help understand with causation, it helps predictor patient recovery, direct appropriate treatment and can be used to establish future needs once a patient has reached MMI.

About Arthur: Dr. Chris Gubbels is a Fort Collins Chiropractor located at Square ONE which specializes in non-surgical treatment of scoliosis and scoliosis bracing. He has published research on non-surgical treatments of spine deformities and presented cases at international research conferences on non-surgical scoliosis treatment. To learn more about Square ONE visit www.squareonehealth.com.

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2.         Association For Safe International Road Travel. Available from: https://www.asirt.org/.

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12.       Maxwell, S. and M. Sterling, An investigation of the use of a numeric pain rating scale with ice application to the neck to determine cold hyperalgesia. Man Ther, 2013. 18(2): p. 172-4.

13.       Gehling, J., et al., Short-term test-retest-reliability of conditioned pain modulation using the cold-heat-pain method in healthy subjects and its correlation to parameters of standardized quantitative sensory testing. BMC Neurol, 2016. 16: p. 125.

14.       Holm, L.W., et al., Expectations for recovery important in the prognosis of whiplash injuries. PLoS Med, 2008. 5(5): p. e105.

15.       Angst, F., et al., Multidimensional associative factors for improvement in pain, function, and working capacity after rehabilitation of whiplash associated disorder: a prognostic, prospective outcome study. BMC Musculoskelet Disord, 2014. 15: p. 130.

16.       Campbell, L., et al., Trauma-focused cognitive behaviour therapy and exercise for chronic whiplash: protocol of a randomised, controlled trial. J Physiother, 2015. 61(4): p. 218.

17.       Elliott, J., et al., Fatty infiltration in the cervical extensor muscles in persistent whiplash-associated disorders: a magnetic resonance imaging analysis. Spine (Phila Pa 1976), 2006. 31(22): p. E847-55.

18.       Kalichman, L., E. Carmeli, and E. Been, The Association between Imaging Parameters of the Paraspinal Muscles, Spinal Degeneration, and Low Back Pain. Biomed Res Int, 2017. 2017: p. 2562957.

19.       Elliott, J.M., et al., Characterization of acute and chronic whiplash-associated disorders. J Orthop Sports Phys Ther, 2009. 39(5): p. 312-23.

20.       Clark, J., et al., What Are the Predictors of Altered Central Pain Modulation in Chronic Musculoskeletal Pain Populations? A Systematic Review. Pain Physician, 2017. 20(6): p. 487-500.