Research Review By Dr. Shawn Thistle©


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Date Posted:

March 2011

Study Title:

A randomised controlled trial of preventive spinal manipulation with and without a home exercise program for patients with chronic neck pain


Martel J, Dugas C, Dubois J, Descarreaux M

Author's Affiliations:

Département de chiropratique, Université du Québec à Trois-Rivières, Trois-Rivières, Canada

Publication Information:

BMC Musculoskeletal Disorders 2011, 12:41 (doi:10.1186/1471-2474-12-41)

Background Information:

Non-specific neck pain is a common affliction, with an estimated annual prevalence of 30-50% (1). The clinical course of this condition is usually episodic, with the level of symptom severity and recovery varying over time. Although chronic neck pain is not as costly as low back pain, it is estimated that 50-85% of neck pain patients still report symptoms 1-5 years after initial onset, and complete recovery is unusual (2).

The literature to date indicates that manual therapy (spinal mobilization or manipulation), exercise interventions, low level laser therapy (LLLT) and acupuncture (to a lesser extent), are more effective than no treatment, sham, or alternative treatments to stop episodes of neck pain. However, none of these strategies is superior to any other. There is also evidence that supervised exercises, with or without manual therapy, are better than usual or no care (3). Overall, a multimodal approach to care is recommended, and further research is needed in this area to better guide treatment decisions.

It is common in clinical practice for chiropractors and other manipulative therapists to recommend periodic treatments, including manipulation, to keep neck pain at bay and prevent recurrence. This practice however, has always occurred in the absence of supporting scientific literature. This type of ‘maintenance’ or ‘supportive’ or ‘preventive’ care (we won’t debate the pros and cons of using one term versus another here) is often initiated after the resolution of an episode of neck pain, is normally elective, and is not based on clinical symptoms (i.e. the patient is to report for treatment even in the absence of pain).

To investigate this concept, the authors undertook this study on patients with non-specific chronic neck pain with two goals in mind:
  1. To assess the efficacy of spinal manipulative therapy (SMT) with and without a home exercise program; and
  2. To compare preventive SMT with no treatment over the course of 10 months.
The authors hypothesized that those receiving SMT + home exercise in a preventive manner would have less pain and better function than those receiving no preventive treatment.

Pertinent Results:

  • 108 subjects received treatment in the symptomatic phase of the trial
  • After randomization for the second phase, 10 dropouts resulted in unequal group sizes: SMT (n=36), SMT + home exercise (n=33) and attention-control (n=29)
  • Baseline characteristics were similar among the three groups except there were more males in the attention-control group and slightly fewer subjects in that same group who reported pain for less than 1 year
  • Average pain levels on VAS on intake was 3.6 and the average NDI score was 23.1
  • In the symptomatic phase - subjects experienced a reduction in pain by an average of 1.2cm on the VAS, 4.9 on the NDI and 6.5 points on the Bournemouth Questionnaire (BQ) – only the VAS and BQ values are clinically significant. ROM values also increased, but clinical significance for ROM have not been established in the literature for chronic neck pain patients.
  • During the preventive phase - no significant between group differences were noted.
  • However, a majority of the participants in the attention-control group (16 patients; 55%), the SMT group (20 patients; 56%) and the SMT + exercise group (24 patients; 73%) stayed below a level of clinically acceptable pain (2 point difference from the symptomatic phase baseline VAS score) during the preventive phase of the trial.
  • Adherence was excellent in all groups for clinic visits, and exercise adherence was 48% in the combined group (which is similar to values observed in similar studies).
  • No serious adverse events were recorded during this trial.
  • Not surprisingly, the attention-control group used significantly more co-interventions and ice during the trial.

Clinical Application & Conclusions:

Some practitioners may be disappointed with the results of this study. Since investigation into the merit of ‘preventive’ care is in its infancy, more research is needed and sure to follow. That being said, we, as a group of professionals, must be ready to accept the results as they emerge and adapt our practice patterns accordingly. This study, at least, supported the feasibility of conducting a larger trial like this one.

In this study, the results from the symptomatic phase mirror those from other studies on manipulation for neck pain (4-8) – that is, SMT appears to be at least as beneficial as other treatments. Of course, the non-blinded and non-randomized nature of this phase of the study reduces its potential contribution to the overall literature in this area. The overall goal of this paper was to evaluate the preventive phase, however. The results from the preventive phase of the study were equivalent across all groups – SMT, SMT + exercise and attention-control. Overall, SMT, alone or in combination with exercise, did not provide superior results to no treatment. The authors appropriately mention the possibility that the attention-control group’s use of more co-interventions and ice may have made their results similar to the other treatment groups, but this of course could not fully explain these results and they mention that.

They also raise the possibility that treatment outcomes may have been affected by the 3 individual chiropractors who administered the treatments. Again, this may have contributed but could not explain the results entirely (we likely wouldn’t even be discussing this factor if the results were more favorable, would we?).

Personally, I think the fact that subjects had relatively low pain and disability scores at the outset of this study may have limited its ability to detect meaningful benefits from treatment. As most of us know, most neck pain does resolve, certainly within the 10 month timeframe they employed for the preventive phase.

In conclusion, this study had some drawbacks and cannot be relied upon to provide the final answer on this sort of treatment, but it should get us thinking about how we manage our chronic neck pain patients. Just because SMT may not be the key element in a treatment doesn’t mean we can’t help out patients! Keep them active and engaged in managing their own neck pain, be it through stretches, general exercise, relaxation, home icing, and so on.

Communicate with your patients – if they feel periodic treatments are helpful, they have every right to come in and you have every right to treat them (remember the ‘patient preference’ component of evidence-informed care?). As further research emerges, we will hopefully gain a fuller understanding of the potential and appropriateness of recommending ongoing preventive treatments.

Study Methods:

Study participants were recruited via radio and print ads locally and the study was conducted on campus at UQTR. Inclusion criteria for this study were:
  • age between 18-60
  • a primary complaint of non-specific chronic neck pain (defined as pain of mechanical origin in the neck region, with or without radiation to the arm, trunk, or head) pain for > 12 weeks
  • no physical therapy, chiropractic treatment or rehabilitation directed toward the neck
  • willingness to adhere to the study protocol and sign informed consent
Subjects were NOT excluded if they had concurrent low back pain, headaches, or non-radicular pain in the upper extremity (as long as neck pain was their primary complaint). Subjects were excluded if they had: neck pain due to a motor vehicle accident, neck surgery, severe osteoarthritis and inflammatory arthritis, neurological, cardiovascular, infectious, metabolic and endocrine diseases, pregnancy and any cardinal signs of potential vertebral artery dissection.

This study was divided into 2 phases:
  1. A non-randomized section (symptomatic phase) where all participants received a short course of treatment including SMT; then
  2. A randomized section where subjects were randomized into one of three parallel groups (see below) – this phase lasted 10 months.

During the first phase of the trial, all subjects received a short course of SMT treatments. Manipulations were administered by clinicians with at least 3 years experience (all chiropractors). Each treatment session lasted 10-15 minutes and included no more than 4 manipulations directed to the neck and upper thoracic regions. Myofascial or trigger point release was allowed but was kept to a minimum.

This phase lasted 5-6 weeks (no treatment frequency information was included). No advice or education was administered in this phase, and the chiropractors and patients were blinded to their preventive phase.

During the 10 month preventive phase of the trial, co-interventions including medication, other manual or physio-therapy and massage therapy were discouraged. Subjects were instructed to consult the treating study chiropractor before seeking such treatment. Patients in all three groups received the same written instructions and an ice pack they could use. The interventions in the 3 groups were as follows:
  1. SMT group: received one treatment per month for 10 months, with each treatment including a maximum of 4 manipulations to the cervical spine and upper thoracic region.
  2. SMT + home exercise group: received the same SMT treatment as described above, in addition to a low-tech home exercise program consisting of: ROM for warm-up and cool down, 4 stretching/mobilization and 4 strengthening exercises (concentric and isometric contractions) of the cervical and upper thoracic spine, principally flexion/extension, lateral flexion and rotation of the cervical spine. Three series of each exercise were performed during a training session, with a 30- to 60-second rest period between each series. A complete training session lasted between 20 to 30 minutes. Subjects were instructed to perform this program 3 times per week and received instruction and minor modifications (as needed) from a kinesiologist during the study. Adherence was measured using a weekly diary.
  3. Attention-control group: received no treatment, but did attend the clinic every 2 months for visits lasting about 30 minutes (to allow for equal attention among groups). Subjects completed outcome measures and were only palpated.
Outcome Measures:
Outcomes were measured at baseline, at the beginning of the preventive phase and every two months during the preventive phase. The main outcome measures used in this study was the Visual Analogue Scale (VAS), Neck Disability Index (NDI) and Bournemouth Questionnaire. Improvement was defined as a 2 point reduction in pain (on VAS) that was maintained during the prevention phase of the trial. Cervical ROM was also measured using a cROM unit. Secondary outcomes included the Fear Avoidance Beliefs Questionnaire (FABQ) and the Short-Form-12 (SF-12).

Statistical methodology was standard for this type of study: One-way ANOVA was performed for baseline values of continuous variables. T-tests for dependent samples were conducted on primary and secondary outcomes to analyze data from the symptomatic phase of the trial (pooled data).

Study Strengths / Weaknesses:

This study had some limitations that readers should keep in mind:
  • No placebo SMT procedure was employed, however an acceptable placebo technique currently does not exist. Therefore, the subjects, chiropractors and assessors were all non-blinded.
  • Treatment frequency during the first phase of the trial was not standardized (at least if it was, it was not reported).
  • Subjects and assessors were not blinded to group allocation.
  • Due to an uneven number of dropouts, there were not 35 subjects per group, which the authors needed to reach statistical power…future studies should incorporate larger study groups.
  • Subjects had relatively low levels of pain and disability at study onset, which may have limited the statistical ability of this study to reveal a meaningful effect of treatment.

Additional References:

  1. Hogg-Johnson S et al. The burden and determinants of neck pain in the general population: results of the Bone and Joint Decade 2000-2010 Task Force on Neck Pain and Its Associated Disorders. Spine 2008; 33(4Suppl): S39-51.
  2. Carroll LJ et al. Course and prognostic factors for neck pain in the general population: results of the Bone and Joint Decade 2000-2010 Task Force on Neck Pain and Its Associated Disorders. Spine 2008; 33(4 Suppl): S75-82.
  3. Hurwitz EL et al. Treatment of neck pain: noninvasive interventions: results of the Bone and Joint Decade 2000-2010 Task Force on Neck Pain and Its Associated Disorders. Spine 2008; 33(4 Suppl): S123-152.
  4. Giles LG, Muller R. Chronic spinal pain: a randomized clinical trial comparing medication, acupuncture, and spinal manipulation. Spine 2003; 28(14):1490-1502.
  5. Cleland JA et al. Immediate effects of thoracic manipulation in patients with neck pain: a randomized clinical trial. Man Ther 2005; 10(2): 127-135.
  6. Koes BW et al. Randomised clinical trial of manipulative therapy and physiotherapy for persistent back and neck complaints: results of one year follow up. BMJ 1992, 304(6827): 601-605.
  7. Ylinen J, Kautiainen H, Wiren K, Hakkinen A. Stretching exercises vs manual therapy in treatment of chronic neck pain: a randomized, controlled cross-over trial. J Rehabil Med 2007, 39(2):126-132.
  8. Bronfort G, Evans R, Nelson B, Aker PD, Goldsmith CH, Vernon H: A randomized clinical trial of exercise and spinal manipulation for patients with chronic neck pain. Spine 2001; 26(7):788-797.