Dry needling to a key myofascial trigger point may reduce the irritability of satellite MTrPs.
OBJECTIVE
To investigate the changes in pressure pain threshold of the secondary (satellite) myofascial trigger points (MTrPs) after dry needling of a primary (key) active MTrP.


METHODS
Single blinded within-subject design, with the same subjects serving as their own controls (randomized). Fourteen patients with bilateral shoulder pain and active MTrPs in bilateral infraspinatus muscles were involved. An MTrP in the infraspinatus muscle on a randomly selected side was dry needled, and the MTrP on the contralateral side was not (control). Shoulder pain intensity, range of motion (ROM) of shoulder internal rotation, and pressure pain threshold of the MTrPs in the infraspinatus, anterior deltoid, and extensor carpi radialis longus muscles were measured in both sides before and immediately after dry needling.


RESULTS
Both active and passive ROM of shoulder internal rotation, and the pressure pain threshold of MTrPs on the treated side, were significantly increased (P < 0.01), and the pain intensity of the treated shoulder was significantly reduced (P < 0.001) after dry needling. However, there were no significant changes in all parameters in the control (untreated) side. Percent changes in the data after needling were also analyzed. For every parameter, the percent change was significantly higher in the treated side than in the control side.


CONCLUSIONS
This study provides evidence that dry needle-evoked inactivation of a primary (key) MTrP inhibits the activity in satellite MTrPs situated in its zone of pain referral. This supports the concept that activity in a primary MTrP leads to the development of activity in satellite MTrPs and the suggested spinal cord mechanism responsible for this phenomenon.
Hsieh
Yueh-Ling
YL
Department of Physical Therapy, Hungkuang University, Salu, Taichung, Taiwan.
Kao
Mu-Jung
MJ
Kuan
Ta-Shen
TS
Chen
Shu-Min
SM
Chen
Jo-Tong
JT
Hong
Chang-Zern
CZ
D006801:Humans; D009209:Myofascial Pain Syndromes / Q000628:therapy*; D009339:Needles; D053591:Referred Pain; D010812:Physical Stimulation / Q000379:methods; D026741:Physical Therapy Modalities; D016059:Range of Motion, Articular; D020069:Shoulder Pain / Q000628:therapy*