Effects of Superficial and Deep Dry Needling on Pain and Muscle Thickness in Subject with Upper Trapezius Muscle Myofascial Pain Syndrome

Background: Dry needling is one of the main therapeutic approaches in patients with Myofascial pain syndrome. Few studies have been compared the superficial and deep dry needling methods in these patients. Objective: To evaluate the effects of superficial and deep dry needling on pain and muscle thickness in subjects with upper trapezius myofascial pain syndrome. Design: A randomized quasi-experimental double-blinded trial. Methods: 50 subjects with upper trapezius myofascial pain syndrome (age=26/08 ± 4/62, weight=63/88 ± 8/71 kg, height=167/7 ± 4/82 cm, pain duration=9/75 ± 7/05 m) randomly assigned to the superficial (n=25) and deep (n=25) dry needling groups. The pain and maximum thickness of upper trapezius muscle in rest, fair and normal contractions were measured by visual analogue scale (VAS) and an ultrasound device respectively before and after the intervention as well as 7 and 15 days follow-up. Results: The mixed-model ANOVAs revealed a significant group-by-time interaction (F=44.03, p<0.001) for pain and muscle thickness in rest (F=67.00, p<0.001), fair (F=108.73, p<0.001) and normal contraction (F=17.73, p<0.001). The main effects of group and time were statistically significant for pain, rest, fair and normal muscle thickness (p<0.001). There were not any significant differences in rest, fair and normal muscle thickness after intervention as well as 7 and 15 days follow-up. Conclusion: Both superficial and deep dry needling techniques induced significant short-term changes in the VAS. Muscle thickness in rest, fair and normal contractions did not show any significant changes between the groups.