title: Additional effects of transcranial direct-current stimulation and trigger-point injection for treatment of myofascial pain syndrome: a pilot study with randomized, single-blinded trial.
abstract: BACKGROUND
  Chronic pain caused by myofascial pain syndrome (MPS) results in generalized and debilitating conditions. Trigger-point injection (TPI) is the mainstay of MPS management to reduce acute and localized pain. Other adjunctive intervention to modulate the central pain pathway might be helpful if they are combined with TPI. Transcranial direct-current stimulation (tDCS), which is a form of neurostimulation, has been reported to be safe and effective in treating chronic pain by changing cortical excitability.
  
  
  OBJECTIVE
  To determine whether there is an additional effect of tDCS and TPI to reduce pain in patients with MPS.
  
  
  METHODS
  Twenty-one patients with newly diagnosed MPS of shoulder girdle muscles.
  
  
  METHODS
  Patients were randomly assigned into 1 of 3 groups (2 active and 1 sham stimulation groups) and received TPI. Immediately after TPI, tDCS (2 mA for 20 minutes on 5 consecutive days) was administered. For the active stimulation groups, tDCS was applied over 2 different locations (primary motor cortex and dorsolateral prefrontal cortex [DLPFC]).
  
  
  METHODS
  Visual analogue scale (VAS), Pain Threshold Test, and short form of the McGill Pain Questionnaire were measured before and immediately after stimulation for 5 consecutive days.
  
  
  RESULTS
  The mean VAS values were decreased in all three groups after 5 days. There was a significant change between before and after stimulation only in the DLPFC group. The significant change in the mean VAS value was shown from after the second stimulation session (p=0.031), and this remained significant until the last stimulation session (p=0.027).
  
  
  CONCLUSIONS
  This study suggests that tDCS over DLPFC may have additional effects with TPI to reduce pain in patients with MPS. tDCS over DLPFC can be used to reverse central pain pathway by modulating cortical plasticity.
authors.affiliation: 1 Department of Rehabilitation Medicine, Seoul National University Hospital , Seoul, South Korea .
authors.forename: Yoon-Hee
authors.initials: YH
authors.lastname: Choi
authors.forename: Sung-Jin
authors.initials: SJ
authors.lastname: Jung
authors.forename: Chang Han
authors.initials: CH
authors.lastname: Lee
authors.forename: Shi-Uk
authors.initials: SU
authors.lastname: Lee
mesh_terms: D000368:Aged; D059350:Chronic Pain / Q000628:therapy*; D005260:Female; D006801:Humans; D007271:Injections, Intradermal; D008297:Male; D008875:Middle Aged; D009209:Myofascial Pain Syndromes / Q000628:therapy*; D010147:Pain Measurement; D010865:Pilot Projects; D017397:Prefrontal Cortex; D012782:Shoulder; D012785:Shoulder Joint; D016037:Single-Blind Method; D065908:Transcranial Direct Current Stimulation; D061028:Trigger Points