MVA: Collar, Act as Usual, or Mobilization?
Critical Appraisal
Kongstead A, Qerama E, Kasch H, Bendix T, Winther F, Korsholm L, and St ehelin Jensen T. Neck Collar, “Act-as-Usual” or Active Mobilization for Whiplash Injury? A Randomized Parallel-Group Trial. SPINE, Volume 32, Number 6, Pages 618-626
- THERAPY STUDY: Are the results of the trial valid?
What question did the study ask? How to prevent chronic issues after whiplash injury after initial injury.
Patient group was aged 18-70, exposed to a front or rear end car collision less than 72 hours ago and could be examined within 10 days of the time of collision.
Intervention: Comparison of the effects of immobilization in a semi-rigid collar, mobilization of the cervical spine, and advice only, following a whiplash injury.
Measures of outcome: pain, ROM, neck disability index, work capability
Outcome(s) – Almost similar across all groups.
1a. R- Was the assignment of patients to treatments randomised?
Yes. This was a prospective, randomized trial that took place from May10, 2001 to June 17, 2004. Patients were randomized by the project nurse who included those who were deemed high risk by allocation score. Those were then assigned into 3 groups by a computer.
1b. R- Were the groups similar at the start of the trial?
Yes . Patients were a match for age, gender, time from accident, and car collision direction (except for front end oblique angle).
2a. A – Aside from the allocated treatment, were groups treated equally?
Yes. All groups were treated for 6 weeks; all were allocated to high risk for developing persistent symptoms.
However, some participants sought other treatment outside of the study, and some patients were noncompliant.
2b. A – Were all patients who entered the trial accounted for? – and were they analysed in the groups to which they were randomised?
Yes. The authors accounted for losses in all groups to follow up. The act-as-usual group had a higher dropout rate and reasons why could not be determined. The collar only group had poor compliance and those that stopped wearing the collar had better outcomes. There was also a high number of cotreatments with percentages listed. The authors discussed how this could have had an impact on outcomes.
3. M – Were measures objective or were the patients and clinicians kept “blind” to which treatment was being received?
Yes. Participants scored themselves with respect to pain using NPRS 0 to10 for neck pain and headache and used the Copenhagen neck functional disability scale. Objective data from examinations included: AROM of cervical spine, and a neurologic examination. The examiners were blinded to the treatment groups and had no access to interventions.
What were the results?
How large was the treatment effect?
The relative risk tells us how many times more likely it is that an event will occur in the treatment group relative to the control group. An RR of 1 means that there is no difference between the two groups thus, the treatment had no effect. An RR < 1 means that the treatment decreases the risk of the outcome. An RR > 1 means that the treatment increased the risk of the outcome.
Relative Risk for Improvement for baseline:
Collar Group: .38
Act as Usual: .33 (using as a control because it did not have an assigned additional intervention)
Mobilization Group: .40
Collar/Usual: .38/.33= 1.15
Mobilization/Usual: .40/.33 = 1.21
Since the relative risk of the collar and mobilization in this study is nearly one, it does not seem that either treatment is more likely to help over act as usual.
The absolute risk reduction tells us the absolute difference in the rates of events between the two groups and gives an indication of the baseline risk and treatment effect. An ARR of 0 means that there is no difference between the two groups thus, the treatment had no effect.
ARR for improvement for baseline:
Collar: .33-.38= -0.05, – 5% (outcome was 5% worse than act as usual.)
Mobilization: 0.33-0.40= -0.07, -7% (outcome was 7% worse that act as usual)
The relative risk reduction is the complement of the RR and is probably the most commonly reported measure of treatment effects. It tells us the reduction in the rate of the outcome in the treatment group relative to that in the control group.
RRR= 1- RR
RRR collar= 1-1.15 =-0.15, -15%
RRR mobilization = 1 – 1.21 – -0.21 -21%.
Neither mobilization nor collar demonstrate greater improvement from baseline relative to act as usual.
The number needed to treat represents the number of patients we need to treat with the experimental therapy in order to prevent 1 bad outcome and incorporates the duration of treatment. Clinical significance can be determined to some extent by looking at the NNTs, but also by weighing the NNTs against any harms or adverse effects (NNHs) of therapy.
NNT = 1/ ARR:
NNT Collar = 1/-0.05 = 20
NNT mobilization = 1/-0.07 = 14
Would indicate that the use of a collar and mobilization in this population makes patients worse that treat as usual.
How precise was the estimate of the treatment effect?
Precision is lacking as there is no significant effect noted in any of the outcome measures. No outcome variables have a p value of 0.05. ie. ability to work: the confidence interval for active mobilization and use of a collar overlapped with that of act as usual.
Will the results help me in caring for my patient? (ExternalValidity/Applicability)
According to these results, the advice of “act as usual” can be more helpful than wearing a collar. This suggests we encourage our patients to remain active and alleviate their fears of activity after an accident. Treatments should incorporate the restoration of normal cervical ROM with exercise prescription. The secondary outcome measure of pain appears to be the best measure of therapeutic effectiveness.
Mobilization is not well defined in this study: “If symptoms did not respond to the MDT testing or if the there was insufficient response to the active intervention during the course of treatment, passive mobilization and soft tissue techniques to the cervical spine and upper back were added.”
Are the likely treatment benefits greater than the potential harms and costs?
All three interventions are less costly than injections, prolonged prescription pain medication, and MRI’s. Perhaps we need to be identifying subgroups of WAD patients that respond to particular interventions.
Suggested improvements
- Active cervical ROM could be included as a measure of patient’s physical impairment, because severity of injury often correlates to reductions in ROM and can be a predictor of chronicity.
- A true control group would have helped.
- Patients sought treatment outside of the study thereby affecting outcomes.
- A soft collar rather than a rigid collar would improve compliance.
To see the study click: https://www.ncbi.nlm.nih.gov/pubmed/17413465