Whiplash: Causation and Predictions

PUT ON YOUR THINKING CAPS, CAN YOU GUESS WHAT I AM?

Usually I have an acute traumatic onset and have difficulty resolving. Sometimes I hurt right away, but may also decide to show up a few days late. Of course my prognosis changes in those with high anxiety or post-traumatic stress, and despite commonly held beliefs by medical practitioners, compensation may not be that important. Finally, no one seems to agree on how or when to start treating me because health care delivered too early or too late appears to protract the course of recovery; but if the person starts gradually resuming daily life activities I tend to go away...but only for half of those afflicted.

If you haven’t guessed it by now, this clinical conundrum is a Whiplash Associated Disorder (WAD). WAD is a complex disorder that occurs during a motor vehicle collision. Typically, quick and rapid acceleration and deceleration forces are imparted onto vehicle passengers causing a whole array of symptoms such as neck, back, and shoulder pain, dizziness, tinnitus, post traumatic stress and anxiety. Some local statistics from the Insurance Corporation of British Columbia (ICBC) which insures and protects motorists, cyclists, and pedestrians in British Columbia, Canada has reported a steady increase in the amount of crashes year to year from 260,000 reported in 2013 to 300,000 in 2015 (1). From these crashes, about 50,000 people in British Columbia will sustain an injury and unfortunately, the evidence-base suggests only half will make a full recovery with the other half remaining symptomatic at 6-months and beyond. Since only half make a full recovery, are there any risk factors for persistent symptoms from acute whiplash? With dwindling health care resources, how do we decide who to deliver treatment to? Does a complex treatment approach inclusive of pain neuroscience education change outcomes in these patients?

“Risk factors: things related to incidence, something that increases the frequency of some disease or condition.”

Which of these could be risk factors for persistent symptoms after an acute whiplash injury?

If you were to take a guess, what do you think would increase in the risk of having persistent whiplash symptoms? Is it patient demographics, collision parameters or past medical history? What about initial presenting signs and symptoms? There is a ton of research looking at this question, but more recently a systematic review from Walton et al. analyzed risk factors for chronic symptoms with acute whiplash (2). Of the 28 different pooled risk factors identified only two really stood out as having some potential clinical utility. But first, the following variables did not seem to be as important: 1) patient demographics such as having less than post-secondary education, being older (age 50 to 55 years), and being of female sex created only a small 1 to 2 fold increase in risk for persistent symptoms, (2) collision parameters such as being involved in a rear-end, front-end or side collision and self-reports of a ‘severe’ collision were not risk factors for persistent symptoms, and (3) neither was pre-existing neck pain or reports of headache.

So what were the really important variables? From this study the pooled results suggest that clinicians look for the following:

1. High initial self-reported neck pain intensity: a score of 5.5 /10 was associated with a 6-fold increased risk of persistent symptoms at 6-months (OR = 5.63; 95% CI: 3.76, 8.43)

2. High initial self-reported neck disability: NDI scores greater 14.5/50 was associated with a 15-fold increased risk of persistent symptoms at 6-months (OR = 15.52, 95% CI: 1.67,144.43). Caution should be given to the wide confidence interval suggesting inaccuracy of the point estimate.

BASED ON SOME INITIAL BASELINE ASSESSMENT FINDINGS WE CAN IMPROVE OUR PROGNOSTICATION SKILLS TO GUIDE OUR MANAGEMENT.

It appears that how a patient perceives the events surrounding a WAD dictates the prognosis, not the physical factors. Perhaps it might be reasonable to suggest the more risk factors present the greater the odds of WAD symptoms persisting, but this has not been studied to date. Nonetheless, another study to consider when trying to determine the prognosis of acute whiplash is from the work of Ritchie and colleagues. Authors derived and externally validated a clinical prediction rule (CPR) to help identify acute WAD patients who either develop chronic moderate/severe disability and pain or make a full recovery. This is what they found:

WHO IS MORE LIKELY TO GO HAVE ONGOING “MODERATE TO SEVERE” SYMPTOMS?

• Initial high levels of disability: NDI > 20/50

• Age > 35 years

• Hyperarousal subscale (PDS) > 6 (Trouble sleeping, irritability, difficulties concentrating, being overly alert, and being easily startled)

The CPR possesses high specificity and good positive predictive values (90%) which suggests this tool could be great for identifying patients who may experience ongoing moderate to severe pain and disability (3). Conversely, the probability of a full recovery was 80% for younger individuals who presented with initial lower levels of neck disability.

Who is more likely to go make a “full recovery”?

• NDI < 16/50

• Age <35 years

This scale may provide valuable information to clinicians and assist them in prognosticating. Furthermore, it may help identify those patients that may benefit from more intensive interventions secondary to the possibility of prolonged recovery.

“Prognostic factors, things which assist in the prediction of the occurrence of a future event or outcome”

The term recovery is a loaded one since this has yet to be operationalized in the literature, but depending on what you read, recovery could mean anything from symptom resolution or improvement to some arbitrarily identified cut-off point in pain, disability or psychological distress scores, return to work, or time to claim closure. Personally, I would define recovery as reaching our patient’s goals both in the short and long term which likely includes things like pain relief and returning to activities of daily living.  

In general, this topic has been summarized well by a very thorough and recent systematic review by Sarrami et al suggesting that “a ‘typical’ whiplash patient with a poor outcome (that is, prolonged pain and disability) can be depicted as having severe pain and anxiety.” (4). For most clinicians, this statement may not be surprising, that is pain and disability often co-exist with psychosocial factors. As a profession, I believe we have gotten better at recognizing these variables, but arguably not as good at addressing them. However, whiplash patients seem to present unique challenges, one of which is a high rate of subjective reports of pain in the presence of what appears to be good daily levels of functioning. Now the question becomes, is there anything else that could account for the differences between the amount pain reported and levels of function? In the Sarami review, it was also suggested that those seeking or who have sought legal advice and received significant amounts of early healthcare did not fare well. Of course, this is only correlation and not causation so we can only speculate, but perhaps the expectation of being injured and compensated based on the amount of disability experienced changes the path to recovery.

In which scenario would you naturally expect there to be greater likelihood for prolonged disability? How do we respond to each of these scenarios?

Consider the following survey that looks at another group of individuals with completely different expectations surrounding motor vehicle accidents: authors sent out 124 surveys to demolition derby drivers asking about the number of events they have participated in and questions surrounding neck pain intensity and duration. 50 surveys were returned and 40 were completed. Despite being in several collisions at high and low speed, with about half being rear-enders, drivers experienced less neck pain and disability than one might expect. Drivers were generally younger (~28 years old), participated in about 30 career events each, and reported about 50 collisions per event. Of those surveyed, 85% of drivers reported neck pain but for nearly all of them it resolved within 3 weeks (5). Even more astounding was only 5% of drivers reported chronic neck symptoms! What could possibly account for this? Perhaps this lends insight into the power of expectations:

1. Derby drivers likely expect and assume the inherent risks of the sport versus

2. The general population which may expect to have neck pain and compensation after an accident.

Authors of this study suggest derby drivers could be “less likely to succumb to perceptions of victimhood or illness behavior and symptom magnification, which prolong recovery.” This could also lend insight to is the complexity of the pain experience. Pain is context dependent and there are multiple levels of pain processing occurring simultaneously in the brain which ultimately influences our behavior (6).

WHAT SHOULD WE DO ABOUT IT?

For those who fall into the moderate to severe group, there is a 90% chance that they will experience ongoing moderate/severe pain and disability with many patients' recovery plateauing around the 3 month mark. But why is this occurring and is there anything we can do about it? Should we just throw our hands up and give up on this population? No way! Now I can only speculate, but it’s questionable if these patients are receiving the right messages at the right time and getting treatment that is goal-oriented and specific to their needs. This is a complex condition and every patient is going to need something a little different, thus, I could only imagine how difficult it must be to study. For treatment of acute whiplash consider the following:

1. Patient Education: there is moderate to strong evidence that patient education does improve outcomes in this population whether it is delivered verbally, in a booklet or in video format (7). More comprehensive treatment plans are still required for those at risk for chronic symptoms but here is a good example of education booklet for patients authored by two leaders in the whiplash field. Give it to your patients. 

2. Exercise and Manual Therapy: the combination of progressive exercise directed at the upper quarter (neck, back, and shoulders) and manual therapy improve outcomes in the short-term (8). The addition of manual therapy as expected, does not change recovery time for mechanical neck disorders but probably makes people more comfortable along the way.

3. Gradual Return to Work: many patients experience lost time from work. They likely need some ongoing coaching, support, and reassurance during the gradual return to work period with the addition of pain education and progressive exercise along the way.

4. Psychosocial Factors: are patients getting the right treatment for anxiety or PTSD? Although a trial that Jull et al published in 2013 did not find improvements in outcomes for acute whiplash injuries treated with a pragmatic multidisciplinary approach (9), other studies have found improvements in disability and pain in chronic whiplash patients with high levels of post traumatic stress when they receive a cognitive behavioural treatment approach (10).

5. Patient expectations: more and more research is showing the importance of patient expectations and for acute whiplash they are no different. Those who have a poor expectation for recovery, even after controlling for symptom severity, are likely to have persistent symptoms (11).  If patients do not believe they will improve, this needs to be addressed from Day 1. This begs the question: can we be providing reassurance of a favorable prognosis if the research says otherwise? Although it has been said “reassurance is a bloody good pain killer.”

Patients who meet the full recovery criteria may require minimal treatment that consists of pain neuroscience education, reassurance, and encouragement to continue with ADL’s with a few ongoing appointments over a 4 to 6 week period. For those who fall into the moderate to severe subgroup, a multimodal treatment program should be recommended for patients. The research is quite limited in this area, but as previously mentioned, there has been some good work done here. Jull et al took acute whiplash patients and randomized subjects to a usual care group or 10-weeks of multidisciplinary individualized care. The primary outcome used was the Neck Disability Index measured at 11-weeks, 6 and 12-months. The usual care group (n=52) was free to pursue usual care from health practitioners of their choice and the multidisciplinary group (n=49) were given treatments prescribed on an individual basis receiving medical, physiotherapeutic and psychological care concurrently. The results: baseline NDI had a significant negative effect on recovery and at 6-month follow-up, with 64% of multidisciplinary group and 50% of the usual care group remained non-recovered (9). Again, only 50% of study participants recovered and the pragmatic and usual care groups experienced comparable results for pain, physical and psychological measures at all time points. Most improvement occurred within the first 11 weeks, with outcomes appearing to plateau at this point. Unfortunately the trial did not stratify patients who were at high risk for persistent symptoms and makes you wonder if the results could have been different.

One final consideration: many conditions seem to respond favorably to early mobilization such as ankle, knee, and hamstring injuries. Noteworthy is some research looking at early healthcare utilization after acute whiplash injury and recovery time. There is a body of evidence suggesting that early aggressive treatment of whiplash injuries may actually hinder recovery. One study investigated patterns of care between GP, chiropractors, and specialists, utilization rates of care, and time to recovery from acute whiplash. Generally what was found is that as the intensity of care received during the first 30 days after the collision increased, the rate of recovery also increased (12). Similar results have been reproduced in other studies comparing combinations of GP and physiotherapist care (13). Of course this is a correlation not a causal relationship but should draw our attention to ensure we do not contribute to iatrogenic illness by over medicalizing the patient with a WAD.

WHAT TO TAKE FROM ALL OF THIS?

1. Attempt to stratify patients into 2 basic subgroups:

   1. Full recovery: those who are younger and present with lower pain and disability levels at baseline.

   2. Moderate to severe: those who are older and have high baseline pain and disability levels.

2. Based on patient prognosis, provide a multimodal treatment plan that considers patient expectations for recovery and does not over-medicalize the condition. Ensure to deliver pain neuroscience education, along with some impairment based manual therapy and exercise interventions. If there are signs of PTSD or high anxiety that is unresolving, send a referral for psychology.

3. It would seem that a large subgroup of patients with grade 2 WAD go on to develop persistent pain. Focusing on functional outcomes despite ongoing pain may be a more efficacious approach to these complex patients. This can be accomplished by encouraging early return to work and activities of daily living.

References:

1) http://www.icbc.com/about-icbc/newsroom/Documents/quick-statistics.pdf

2) Walton et al. Risk Factors for Persistent Problems Following Acute Whiplash Injury: Update of a Systematic Review and Meta-analysis. JOSPT. 2013.

3) Ritchie et al. External validation of a clinical prediction rule to predict full recovery and ongoing moderate/severe disability following acute whiplash injury. JOSPT. 2015.

4) Sarrami et al. Factors predicting outcome in whiplash injury: a systematic meta-review of prognostic factors. Orthopaedic Traumatology. 2017.

5) Simotas et al. Neck pain in demolition derby drivers. Archives of physical medicine and rehabilitation. 2005.

6) Moseley and Arntz. The context of a noxious stimulus affects the pain it evokes. PAIN. 2007.

7) Meeus et al. The efficacy of patient education in whiplash associated disorders: a systematic review. Pain Physician. 2012.

8) Gross et al. Conservative Management of Mechanical Neck Disorders: A Systematic Review. Journal of Rheumatology. 2007.

9) Jull et al. Management of acute whiplash: a randomized controlled trial of multidisciplinary stratified treatments. Pain. 2013.

10) Dunne et al. A randomized controlled trial of cognitive-behavioral therapy for the treatment of PTSD in the context of chronic whiplash.Clinical Journal of Pain. 2012.

11) Holm, L. Expectations for recovery important in the prognosis of whiplash injuries. PLoS Med. 2008.

13) Gwendolijne et al. Education by General Practitioners or Education and Exercises by Physiotherapists for Patients With Whiplash-Associated Disorders? A Randomized Clinical Trial. Spine. 2006.