Research Review By Dr. Michael Haneline©


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Date Posted:

January 2014

Study Title:

Short-term usual chiropractic care for spinal pain
A randomized controlled trial


Walker B, Hebert J, Stomski N, Losco B & French S

Author's Affiliations:

School of Health Professions; School of Psychology and Exercise Science, Murdoch University, Murdoch, Australia.

Publication Information:

Spine 2013; 38(24): 2071-2078.

Background Information:

Spinal pain, in particular low back and neck pain, has a considerable socioeconomic impact globally in terms of direct costs (e.g., medical, rehab) and indirect costs (e.g., reduced productivity). Therefore, efficient and successful management of spinal pain is of interest to patients, clinicians, and health care policy makers.

Several systematic reviews have reported that there is uncertainty about the value of chiropractic treatment because of the small treatment effect sizes and methodological limitations in published studies. One of the main limitations of earlier studies on chiropractic treatment for spinal pain is that randomized trials have generally not compared the effects of chiropractic treatment with placebo/sham interventions.

Because of the aforementioned limitations of previous studies, the purposes of this study were:
  1. to examine the effectiveness of a brief chiropractic intervention compared with sham treatment in patients with spinal pain, and
  2. secondarily, to explore the clinical and demographic variables associated with treatment satisfaction.

Pertinent Results:

  • Almost all subjects (98%) had chronic spinal pain, with about 75% of them having the pain for more than 5 years.
  • Usual chiropractic care was found to be superior to the sham intervention in reducing pain intensity, as measured on a Numerical Rating Scale (NRS), and improving physical function, as measured via the Functional Rating Index (FRI); however, the differences were not considered clinically important.
  • About twice as many of the participants who received usual chiropractic care reported global improvement than those who received the sham intervention (48% improved vs. 24% improved), and this difference was considered statistically significant (P = 0.012).
  • 34% of the sham group, and 29% of the usual care group met the minimal acceptable outcome (MAO) threshold, but the difference between groups was not statistically significant (P = 0.42).
  • Treatment satisfaction was higher among those in the usual chiropractic group than the sham intervention group (78% satisfied vs. 56% satisfied), which was statistically significant (P = 0.004).
  • No serious adverse events were reported by any of the participants and the rate of minor adverse events was about the same in both groups. Most commonly reported were increased pain (29% in the sham group and 36% in the usual care group), muscle stiffness (29% in the sham group and 36% in the usual care group), and headache (17% in the sham group and 9% in the usual care group).

Clinical Application & Conclusions:

According to the authors, this study is only the second one to use a sham-controlled design to examine the effectiveness of chiropractic treatment. The study failed to show a clinically meaningful difference between the groups of patients with spinal pain, though a statistically significant difference was found. Nonetheless, it is debatable whether the findings are relevant to chiropractic practice, given that the once per week treatment frequency and duration of two weeks is clearly out of sync with what is typical among practitioners treating chronic low back pain. (See comment below on treatment frequency/duration in the Study Strengths/Weaknesses section.)

When considered in light of research that has been done on dose-response relationships in chiropractic, the take home message is that a higher frequency and longer duration of treatment than was used in this study should be implemented in patients with chronic low back pain.

The fact that no serious adverse events were reported and that the rate of minor adverse events was about the same in both groups strengthens the evidence base on the safety of chiropractic treatment.

Study Methods:

This paper reported on a secondary analysis of a 2-arm parallel-group randomized trial that compared usual chiropractic treatment to a sham intervention to investigate the occurrence of adverse events.

Participants were recruited from the local community using newspaper advertisements. They were randomly assigned to receive usual chiropractic care or sham chiropractic care. The staff members that administered outcome measures were blinded as to group allocation.

Inclusion criteria were as follows:
  • 18 years-of-age or older,
  • current spinal pain (neck, mid-back, or low back pain) of at least 1-week duration,
  • pain of at least 3 out of a maximum 10 on the NRS,
  • English literate, and
  • 12 out of a maximum 40 on the Functional Rating Index (FRI).
Exclusion criteria were:
  • unable to tolerate any intervention potentially provided in usual chiropractic care;
  • spinal pain related to cancer or infection;
  • spinal fracture, spondyloarthropathy, known osteoporosis;
  • progressive upper or lower limb weakness, cauda equina syndrome or other significant neurological condition;
  • recent disc herniation;
  • severe cardiovascular disease, uncontrolled hypertension, cognitive impairment, blood coagulation disorder;
  • spinal surgery in the past year;
  • history of stroke or transient ischemic attacks;
  • pacemaker or other electrical device implanted;
  • substance abuse;
  • pregnancy; and
  • a current compensation claim.
Interventions included usual chiropractic care provided to one group and a sham intervention to the comparison group. Participants were provided a total of 2 treatments, with approximately 1-week between treatments.

All participating chiropractors, including those that provided sham treatment, attended a 3-hour training session covering the trial protocols.

Usual chiropractic care was provided by 8 chiropractors (5 males) and the sham intervention was delivered by 4 chiropractors (2 males). The usual care chiropractors had an average 12.6 years of clinical experience, whereas the chiropractors that delivered the sham only had an average 3.6 years of experience.

Usual chiropractic care was provided in line with the participating chiropractors’ usual treatment approach.

The sham intervention consisted of:
  1. detuned ultrasound,
  2. an Activator instrument that was adjusted to its lowest setting and randomly administered to the spine through a tongue depressor to disperse any remaining force; and
  3. a randomly placed hand on the spine during detuned ultrasound to give a “hands on” experience.
The primary outcome measures were:
  • pain that was rated on an 11-point NRS as an average of current, best, and worst pain in the preceding 48 hours; and
  • physical function assessed by the FRI.
Secondary outcomes were:
  • treatment satisfaction,
  • global perceived change that ranged from - 5 to +5, and
  • minimal acceptable outcome (MAO).
In order for the treatment outcome to be considered clinically important, the researchers looked for minimal clinically important differences (MCIDs) of 2 points on the NRS and 9 points on the FRI.

Study Strengths / Weaknesses:

The treatment frequency and duration in this study was too low to realistically expect clinically important improvements. Participants were provided only 2 chiropractic treatments over a 2 week period, even though previous research has shown that this low-level of chiropractic treatment is less effective than if participants are given more frequent visits over a longer period of time. In fact, Haas et al. (1) reported that pain intensity in chronic LBP patients at 4 weeks was substantially better in patients who received a higher number of visits, with 3 to 4 visits per week over 3 weeks being optimal.

Further, the attempt to blind study participants as to group allocation was not very successful, probably owing to the known difficulties involved in designing a realistic chiropractic sham intervention. In fact, some researchers (2) have asserted that it may not be possible to effectively blind participants in manual therapy trials.

Additional References:

  1. Haas M, Groupp E, Kraemer DF. Dose-response for chiropractic care of chronic low back pain. Spine J 2004; 4(5): 574-83.
  2. Kawchuk GN , Haugen R , Fritz J . A true blind for subjects who receive spinal manipulation therapy. Arch Phys Med Rehabil 2009; 90: 366-8.