Effects of Intramuscular Electrical Stimulation Using Inversely Placed Electrodes on Myofascial Pain Syndrome in the Shoulder: A Case Series

Abstract

Myofascial pain syndrome (MPS) is one of the common musculoskeletal conditions of the shoulder which may develop sensory-motor and autonomic dysfunctions at the various level of the neuromuscular system. The pain and dysfunction caused by MPS were primarily treated with physical therapy and pharmacological agents in order to achieve painfree movements. However, in recent years intramuscular electrical stimulation (IMES) with conventional electrode placement was used by researchers to maximise therapeutic values. But, in this study an inverse electrode placement was used to deliver electrical impulses intramuscularly to achieve neuro-modulation at the various level of the nervous system. Nine patients with MPS were treated with intramuscular electrode stimulation using inversely placed electrodes for a period of three weeks. All nine subjects recovered from their shoulder pain and disability within the few weeks of intervention. So, this inverse electrode placement may be more appropriate for chronic pain management.

Intramuscular Electrical Stimulation Combined with Therapeutic Exercises in Patients with Shoulder Adhesive Capsulitis: A Randomised Controlled Trial

“…The special programmed Vectrostim-100 (Technomed Electronics®, Chennai, India), a double channeled multipurpose electrical stimulator was used to deliver electrical impulses with following parameters; pulse duration of 250-µsec, pulse interval of 3 seconds (1 pulse per 4 seconds) with the stimulus intensity as tolerable by individuals. Each muscle was stimulated for 2-3 minutes (30-45 muscle twitches) with the tolerable intensity twice a week for three consecutive weeks [8].…”

“…Inflammation of the joint capsule and/or periarticular structures has a greater role for the occurrence of shoulder pain, especially during the acute stage SAC [ 5 ]. In later stages, myofascial trigger points (MTrPs) formation is important factor to contribute to the shoulder pain severity, soft tissue tightness and reduced range of motion [ 6 8 ]. The presence of active and latent-MTrPs in the shoulder girdle muscles found to be associated with fear avoidance belief behaviour during upper limb functions in individuals with painful shoulder disorders [ 7 ].…”

Inverse Electrode Placement May Help to Improve Electrotherapeutic Effects in the Field of Chronic Pain Management

“…Furthermore, the flow of ascending impulses may stimulate the higher cortical sensory-motor and associated perceptual neuronal areas. In the other direction, propagation of action potentials in the peripheral motor axons can stimulate the axon terminals and muscle fibers, especially at the level of reference electrode placement [ 6 ]. The enhanced sensory perception can possibly create more awareness and feedback regarding affected dermatomes and myotomes which may increase the efficacy of applied therapeutic currents.…”

“…It is evident that neuronal irritability at the spinal level reduces the muscle's flexibility which causes sustained mechanical loading over the facet joints, spinal nerve roots, and sympathetic ganglions. This excessive stress on the neural structures can be reduced by inducing the relaxation of the spinal segmental musculatures with the application of cathodal electrical impulses over the spinal level instead of peripheral areas [ 6 7 8 ].…”

“…The machno-receptor stimulation under the cathode pole of the spinal level may modulate the transmission of pain impulses along the ascending sensory tracts. Further it may reduce the laminar irritability caused by lateral conduction of chronic pain impulses from the spinal as well as peripheral receptors [ 6 9 ].…”