Does EMG (dry needling) reduce myofascial pain symptoms due to cervical nerve root irritation?

Electromyogr Clin Neurophysiol. 1997 Aug;37(5):259-72.


Objective: EMG examination at tender points affects myofascial pain symptoms related to cervical nerve root irritation.

Methods: Consecutive patients with neck and arm pain had physical examinations immediately before and after having EMGs of bilateral C3-C8 myotomes. Patients were randomly chosen for EMG either at the most tender point along the palpated myofascial band or at a nonselected site. The myotomal presence of > or = 30% incidence of normal duration and amplitude, and polyphasic motor unit potentials confirm the diagnosis of cervical nerve root irritation.

Results: 52% returned patient questionnaires 2 weeks post EMG examination. Group I (82/122 patients [67.2%]), averaged pain relief of 51.8 +/- 21.9%, a mean of 10.2 +/- 8 days; 14% had > or = 75% relief. The number of days of pain relief correlated positively with the percentage of pain relief (p < 0.005), but negatively with the number of nerve roots involved on EMG (p < 0.05). Group 2 (23/42 patients [54.8%]), averaged relief of 39.0 +/- 18.7%, lasting 8.8 +/- 11.2 days. None had > or = 75% pain relief. Both groups' duration of pain symptoms affected onset of relief. Evidence of bilateral multiple-level cervical nerve root irritation, especially noted at bilateral C6 and C7 levels.

Conclusion: EMG at tender points on myofascial bands tends to improve symptoms. Needling these points elicits motor endplate activity and twitches, and induces more relief than when needling random points.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Electromyography / instrumentation*
  • Evoked Potentials, Motor / physiology
  • Female
  • Functional Laterality / physiology
  • Humans
  • Male
  • Middle Aged
  • Motor Endplate / physiology
  • Myofascial Pain Syndromes / physiopathology
  • Myofascial Pain Syndromes / therapy*
  • Neck Pain / physiopathology
  • Neck Pain / therapy
  • Needles
  • Pain Measurement
  • Physical Stimulation
  • Radiculopathy / physiopathology
  • Radiculopathy / therapy*
  • Spinal Nerve Roots / physiopathology*