Research Review by Dr. Steve Burnie©

Date:

May 2008

Study Title:

Immediate effect of Activator trigger point therapy and myofascial band therapy on non-specific neck pain in patients with upper trapezius trigger points compared to sham ultrasound: A randomized controlled trial

Authors:

Blikstad A, Gemmell H

Authors’ Affiliations: Anglo-European College of Chiropractic, England.

Publication Information:

Clinical Chiropractic 2008; 11:23-29.

Summary:

Non-specific neck pain, a common complaint in manual therapy practices, is often caused by a mechanical or myofascial dysfunction. Manual therapists frequently find active myofascial trigger points (TrPs) in these patients and use a variety of methods to treat them. Myofascial band therapy (MBT) is a technique that involves firm thumb pressure applied along the longitudinal myofascial bands of an involved muscle, passing through the active TrP. Although case studies of this technique have shown promise, effectiveness of MBT for neck pain is unknown.

The Activator adjusting instrument (AAI) is a device commonly used by chiropractors as a method of adjusting joints with movement fixations, however it is also occasionally used to address myofascial TrPs. To date, no research has been done to assess the effectiveness of using the AAI for treating trigger points.

Although both myofascial band therapy and the Activator adjusting instrument have been used clinically for years with anecdotal success, there is a lack of research to support their use for non-specific neck pain, in particular neck pain involving trigger points. The purpose of this study was to evaluate the immediate effectiveness of these treatments in such neck pain patients compared to sham ultrasound.

This study was a randomized, placebo-controlled clinical study conducted at the Anglo-European College of Chiropractic (AECC). Patients enrolled in the study were men and women between the ages of 18 and 55 years, with unilateral or bilateral neck pain of between 4 and 12 weeks duration, with a severity of at least 4 on an 11-point scale. All of these patients had at least one active trigger point in the upper trapezius muscle with decreased lateral cervical flexion to the opposite side of the active TrP. A total of 45 subjects (students at AECC) were randomly assigned to one of three groups (15 per group) and had the intervention applied at the most active trigger point in the affected trapezius muscle:
  1. Sham ultrasound
  2. Myofascial band therapy
  3. Activator trigger point therapy (10 thrusts on the TrP with an Activator IV instrument set at a force setting of 3)
All outcome measurements were taken before and after the interventions by an examiner blinded to the intervention used. The primary outcome measure for this study was an 11-point numeric pain rating scale, with a decrease of at least 2 points considered to indicate a clinically significant improvement. Further, a pain pressure algometer was also used to measure pain threshold in the subjects’ upper trapezius trigger points. Finally, a cervical range of motion goniometer was used to measure lateral cervical flexion, with a minimum of 5º increase considered to be clinically important.

Pertinent Results:

  • at baseline, there were no statistically significant differences in any outcome between groups
  • for the primary outcome of pain, the Activator showed vastly superior improvements compared to myofascial band therapy and sham ultrasound (53.3% of subjects were improved compared to 13.3% in each of the other groups)
  • as clinicians care most about effect size rather than the size of statistical significance, the authors of this study reported their results in terms of odds ratios and numbers needed to treat
  • the number needed to treat (NNT) was found to be 2.5 for the Activator group, meaning that for one patient to improve, 3 patients must be treated
  • the odds ratio (OR) was 7.4 in favour of the AAI group, meaning that patients treated with the Activator are 7 times more likely to improve than a patient treated with myofascial band therapy or sham ultrasound
  • for the secondary outcomes of lateral flexion and pain pressure threshold, odds ratios were not significantly different making it impossible to calculate NNT

Conclusions & Practical Application:

This study examined the effectiveness of using an Activator adjusting instrument or myofascial band therapy on trapezius trigger points for non-specific neck pain compared to a placebo (sham ultrasound). Activator trigger point therapy was found to have immediate benefits in reducing pain in patients with sub-acute non-specific neck pain.

The number needed to treat in the Activator group was small (NNT = 2.5), meaning that only 3 patients need to be treated with the Activator trigger point therapy for one patient to improve. The significance of this finding is further punctuated by an odds ratio of 7.4, suggesting that patients treated with the Activator instrument on active trigger points have a seven times greater chance of improving after one treatment than patients treated with myofascial band therapy or sham ultrasound. The use of a placebo was a wise choice for this study, as previous manual therapy papers have been rightly criticized for missing this important comparison.

The results of this study point strongly to the immediate pain relief that can be delivered with the use of an Activator adjusting instrument over active trigger points in the trapezius, however some notes about shortcomings of this study must be mentioned. First, at 15 participants per group, this is a relatively small study that should be validated with larger group sizes. The authors also note that previous studies have shown a transient increase in pain following certain treatments actually results in an increased therapeutic effect – post treatment evaluation of pain, therefore, may have occurred too soon after treatment, particularly the myofascial band therapy. Some subjects expressed difficulty in rating their exact pain level immediately after treatment due to post-treatment soreness.

Perhaps most importantly, the study included only one treatment, and lacked any significant follow-up period, hardly a simulation of true clinical realities. Therefore, the results of this study may be considered of limited clinical value in terms of overall patient care. This study was a good start, however – hopefully it will guide future research to investigate these methods of neck pain treatment and it gives clinicians some justification for using the Activator instrument for treatment of active trigger points.