title: Dry needling to a key myofascial trigger point may reduce the irritability of satellite MTrPs.
abstract: 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.
authors: Department of Physical Therapy, Hungkuang University, Salu, Taichung, Taiwan.
authors: Yueh-Ling
authors: YL
authors: Hsieh
authors: Mu-Jung
authors: MJ
authors: Kao
authors: Ta-Shen
authors: TS
authors: Kuan
authors: Shu-Min
authors: SM
authors: Chen
authors: Jo-Tong
authors: JT
authors: Chen
authors: Chang-Zern
authors: CZ
authors: Hong
mesh_terms: 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*