title: Percutaneous peripheral nerve stimulation for chronic pain in subacromial impingement syndrome: a case series.
abstract: OBJECTIVE
  The objective of this study was to determine the effect of peripheral nerve stimulation (PNS) on pain reduction for those with refractory subacromial impingement syndrome (SIS) and to evaluate the association with reduced disability, impairment, and safety. Our hypotheses are that PNS will be associated with a reduction in pain, impairment and disability, and improvement in quality of life while demonstrating safety.
  
  
  METHODS
  Adults with shoulder pain of at least six months duration were recruited for a three-week treatment of percutaneous PNS applied through a percutaneous electrode to the axillary motor points of the deltoid muscle. Subjects were followed for 12 weeks after treatment. The primary outcome was the worst pain in the last week, and secondary outcomes included pain interference, the Disabilities of the Arm, Shoulder, and Hand questionnaire, shoulder abduction range of motion, and safety. Analysis was with a linear mixed model.
  
  
  RESULTS
  Ten subjects were recruited. Longitudinal analysis demonstrated significant reduction in pain relative to baseline (F(1, 66) = 12.9, p < 0.01). After correcting for multiple comparisons, there were significant reductions at explantation and all follow-up time points when compared with baseline. There were also significant improvements in pain interference (F(1,65) = 15.0, p < 0.01), the Disabilities of the Arm, Shoulder, and Hand questionnaire (F(1,35) = 7.0, p = 0.01), and shoulder abduction range of motion (F(1,35) = 6.3, p = 0.02).
  
  
  CONCLUSIONS
  Intramuscular PNS for chronic shoulder pain due to SIS is a safe treatment associated with pain reduction, lower pain interference with activities of daily living, reduced disability, and improved shoulder abduction. Pain reduction is maintained for at least 12 weeks after treatment.
authors: Cleveland FES Center, Case Western Reserve University, Cleveland, OH (Wilson, Chae), USA; Department of Physical Medicine and Rehabilitation, Case Western Reserve University at MetroHealth Medical Center, Cleveland, OH (Wilson, Harris, Chae), USA.
authors: Richard D
authors: RD
authors: Wilson
authors: Michael A
authors: MA
authors: Harris
authors: Douglas D
authors: DD
authors: Gunzler
authors: Maria E
authors: ME
authors: Bennett
authors: John
authors: J
authors: Chae
mesh_terms: D000328:Adult; D059350:Chronic Pain / Q000209:etiology* / Q000628:therapy*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D010525:Peripheral Nerves / Q000502:physiology*; D019534:Shoulder Impingement Syndrome / Q000150:complications*; D004561:Transcutaneous Electric Nerve Stimulation / Q000379:methods*; D016896:Treatment Outcome
keywords: Chronic pain; electrode placement; nonmalignant pain; percutaneous nerve stimulation; peripheral nerve stimulation