EVIDENCE IN SUPPORT OF MANUALLY RELEASING TRIGGER POINTS? There are growing numbers of studies that suggest the efficacy of manual pressure for releasing myofascial trigger points.

A recent pilot study by Fernández- de-las-Peñas (14) showed that both ischaemic compression and transverse friction massage were equally effective in treating myofascial trigger points. Forty participants with neck pain, aged 19–38 years, were recruited, and all had myofascial points diagnosed according to Simons’ criteria (15). Half of the recruited sample received compression and the other received friction massage. Compressions were applied as they lay supine with the cervical spine in a neutral position. Pressure to the trigger points was gradually increased until the sensation of pressure became painful. At that moment, the pressure was maintained until the discomfort eased by 50%, as perceived by the participant, then the pressure was increased again and maintained until it became uncomfortable again. This compression was repeated for 90 seconds. The outcome measure was

pressure pain threshold (PPT), determined using an algometer. PPT is the minimal amount of pressure (in kg/cm2

) that produces pain as rated

on a visual analogue scale (VAS). On average the PPT increased from 1.8 kg/ cm2

to 2.2 kg/cm2 and the VAS pain

score decreased from 4.6 to 3.8. In the friction massage group, PPT increased from 2 kg/cm2

to 2.35 kg/cm<2 > and

the VAS decreased from 4.9 to 4.2. Paired t-test showed a significant decrease in the PPT and VAS in both treatments. Independent t-testing showed no significant difference between the compression group and the friction massage group. These findings suggest that the

(16). Another study recommends a minimum change of 1.5 kg/cm2 The observed pre-test–post-test

26

compression technique can decrease the sensitivity of myofascial trigger points and reduce levels of pain, but there is some uncertainty about the reliability of the algometer. Historically it has good test–retest reliability, but one recent study recommends a meaningful clinical difference in PPT measured by pressure algometer of 1.77 kg/ cm2

(17).

difference in PPT was 0.4 and this did not exceed the published clinical differences threshold. Such a difference might therefore be due to instrument or measuring errors. Hanten et al. (18) studied forty

volunteers aged 23–58 with a palpable tender sport in the neck or upper back (palpation of which reproduced the subject’s pain) who undertook a home programme of ischaemic pressure and stretching exercises, or active range of motion exercises. Participants who used ischaemic compression showed a significant difference in their VAS pain score and PPT. The pre-test and post-test difference in PPT was 1.2, suggesting that ischaemic compression decreases sensitivity of trigger points. However, the change in PPT did not exceed the clinical difference threshold (18).

Both of the above studies demonstrated a decrease in VAS pain scores, suggesting that ischaemic compression is effective in reducing pain. Both also showed a positive outcome on desensitisation of trigger points, but neither showed meaningful clinical differences in PPT as recommended in the literature. It is worth bearing in mind that the models and makes of devices used in these studies were different. It is possible that some models of instruments are more accurate than others, which may account for some of the differences observed. A systemic review by Rickards (3) concluded that the body of evidence for non-invasive intervention for myofascial trigger-point pain is rather limited. Rickards stated that although non-invasive treatments may be effective, it is not known whether they address the proposed pathological entity or some other process. None of the reviewed studies demonstrated any long-term effects of such treatments, focusing instead on the immediate post-treatment period. This review highlighted several difficulties in producing good- quality research, for example the heterogeneity of the sample population, accurately describing the location of the trigger points undergoing treatment and employing definitive diagnostic criteria. As there is no universal treatment protocol, it is important to document the location of the points and the treatments employed. Most

studies on myofascial trigger point also tend to report the changes as a group average. To better inform decisions about patient management, they should evaluate not only the mean differences between comparison groups, but also the distribution of clinical outcomes within each treatment group.

CONCLUSION

The theory behind the treatment of myofascial trigger points is sound, with plenty of evidence of their aetiology and pathophysiology. Studies have demonstrated that treatment can reduce the level of pain associated with trigger points, as well as reducing their sensitivity. Further high-quality trials are needed to establish these treatments as viable options.

References 1. Kraus H. Diagonisis and treatment of muscle pain. 1988 ISBN 0867151668 2. Simons DG, Mense S. Diagnosis and therapy of myofascial trigger points. Schmerz, 2003;17:419–424 3. Rickards LD. The effectiveness of non-invasive treatments for active myofascial trigger point pain: A systematic review of the literature. International Journal of Osteopathic Medicine 2006;9:120–136 4. Simons DG. Trigger points and limited motion. Journal of Orthopaedic and Sports Physical Therapy 2000;30:706–708 5. Lucas KR. The impact of latent trigger points on regional muscle function. Current Pain and Headache Reports 2008;12:344– 349

6. Simons DG, Hong CZ, Simons LS. Endplate potentials are common to midfibre myofascial trigger points. American Journal of Physical Medicine Rehabilitation 2002;81:212–222 7. Gerwin RD. A review of myofascial pain and fibromyalgia – Factors that promote their persistence. Acupuncture in Medicine 2005;23;121–134 8. Simons D, Do endplate noise and spikes arise from normal motor endplates? American Journal of Physical Medicine and Rehabilitation 2001;80:134–140 9. Simons D, Hong C-Z, Simons L. Endplate potentials are common to mid-fiber myofascial trigger points. American Journal of Physical Medicine and Rehabilitation 2002;81:212–222 10. Shah JP, Danoff JV, Desai MJ, Parikh S, Nakamura LY, Phillips TM, Gerber LH. Biochemicals associated with pain and inflammation are elevated in sites near to and remote from active myofascial trigger points. Archive of Physical Medicine and Rehabilitation 2008;89:16–23 11. Shah JP, Phillips TM, Danoff JV, Gerber LH. An in vivo microanalytical technique for measuring the local biochemical milieu of human skeletal muscle. Journal of Applied Physiology 2005;99:1977–1984

12. Chen, Q, Bensamoun, S, Basford, J. R, Thompson, J. M, An, K. N Identification and quantification of myofascial taut bands with magnetic resonance elastography. Archives of Physical Medicine and Rehabilitation 207;88:1658–1661 13. Bron C, Wenensing M, Franssen JL, Oostendorp RA. Treatment of myofascial trigger points in common shoulder disorders by physical therapy: A randomized controlled trial. BMC Musculoskeletal Disorders 2007;8:107 14. Fernández-de-las-Peñas C, Alonson-Blanco C, Cuadrado ML, Gerwin RD, Pareja JA. The immediate effect of ischemic compression technique and transverse friction massage on tenderness of active and latent myofascial trigger points: A pilot study. Journal of Bodywork and Movement Therapies 2006;10:3–9

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