Effects of Intramuscular Electrical Stimulation on Symptoms Following Trigger Points; A Controlled Pilot Study

Myofascial Pain Syndrome (MPS) is a common disorder of musculoskeletal system. About one third of the people with musculoskeletal disorders have been diagnosed as having MPS. It is a painful condition caused by trigger points. A variety of treatment approaches are used to cure MPS and its associated disorders. This study aimed to investigate the effects of single session Intramuscular Electrical Stimulation (IMES) through dry needling on pain and Range Of Motion (ROM) following trigger points in upper trapezius.
Material and Sixteen volunteers with active trigger points in upper trapezius were randomly divided into two groups: 1) the IMES treatment group (8 females) and 2) placebo group (8 females). In the IMES group, trigger points of the affected side were injected through dry needling, then a burst current (2 Hz) was applied on the muscle while the electrical stimulation steadily increases to form a pain free contraction for the patient. In placebo group, the procedure was exactly the same but there was no applied electrical stimulation through dry needling. Pain sensation by Visual Analog Scale (VAS) and cervical flexion ROM were measured before treatment, immediately after treatment and one week later by another blinded researcher.
VAS scores showed improvement in both groups at the end of the treatment session and also one week later. There was no significant difference between the groups; IMES and placebo in terms of the VAS after treatment session. However, the pain scores were substantially decreased in the IMES group one week after the intervention. The ROMs were significantly lower in placebo group one week after treatment. There was no significant correlation between improvement and duration of symptoms.
Both IMES and placebo methods might be effective in relieving symptoms of patients with the MPS in upper trapezius; however, patients following the IMES treatment showed higher level of improvement during one week after the intervention. Further relevant studies with higher number of volunteers and different treatment protocols are necessary to get high quality evidence.