Poster Number-6 - A Rapid Review of Non-Invasive Electromagnetic Devices for the Treatment of Pain

A Rapid Review of Non-Invasive Electromagnetic Devices for the Treatment of Pain

Purpose:

Acute pain conditions are in continual search for complimentary therapies that reduce reliance on opiates and/or interventional procedures that are painful and costly. Non-interventional complimentary therapies are continually being developed that attempt to address this goal. One area of interest is the delivery of wave-based therapy leveraging ultrasound or electromagnetic waves for the purpose of providing pain relief. A rapid review of the literature and regulatory databases was conducted to illustrate relevant technology.

Methods:

A rapid review was conducted of PubMed and the FDA 510k database to identify relevant technologies that are a) in current use clinically, b) have received a premarket authorization from the FDA via a 510(k), c) deliver variants of wave-based therapy that could be ultrasound, radiofrequency or electromagnetic and d) have an indication of pain-relief or treatment of soft-tissue injuries.

Results:

Four technologies were identified that met the above search criteria. Pulsed electromagnetic field therapy (PEMF) has been on market since 1979. The therapeutic effects of PEMF aim at the cellular and molecular level of very low frequency (< 30 Hz) and low energy (< 400 micro-Tesla) to impart biologic effects. PEMF is indicated for temporary relief of minor muscle and joint aches and pain associated with overextension, strains, sprains and arthritis. Multiple RCT and meta-analysis show favorable effects in knee and finger osteoarthritis.

 

Combined electrochemical therapy (CET) combines two principles for the treatment of peripheral neuropathy: electrical cell signaling treatment (EST) and administration of local anesthetic to the target tissue. The mechanism of action is that the target tissue will experience increased blood flow and oxygen delivery, increased regenerative tissue effects and chemically blocking of pain fibers. EST is delivered via a sequence of varying frequencies of radiofrequency signals which include: 1) slow frequency (1-4 Hz) for nerve stimulation, 2) slightly faster (10 Hz) to produce local vasoconstriction, 3) fast stimulation (100 Hz) to produce local vasodilatation and 4) very fast ( >2 MHz) which fall within the cell membrane refractory period to inhibit action impulse capability resulting in sustained cell membrane depolarization.

 

Extracorporeal shockwave therapy (ESWT) is an extension of shockwave lithotripsy that is used for renal calculi. ESWT delivers high frequency acoustic impulses to the target tissue. This technology was first FDA cleared in 2000 for the treatment of plantar fasciitis. ESWT waves are uniphasic and higher pressure (500 bars) or 1000x stronger than ultrasound. Clinical utility has been shown in multiple RCTs for conditions including but not limited to plantar fasciitis, lateral epicondylitis, patellar tendinopathy, Achilles tendinopathy and non-union of long-bone fractures.

 

Short wave diathermy (SWD) delivers deep tissue heating via electromagnetic waves delivered to the tissue at 27.12 MHz. SWD devices have been FDA cleared for decades but often used bulky drums applicators that hinder targeted localization of thermal effects. Modern designs created hand-held applicators that improve tissue targeting of SWD. Many SWD devices deliver the thermal effects by way of biomagnetic induction that results in heat to deeper tissue layers (4 cm below the dermis). SWD is indicated for pain relief of acute musculoskeletal injuries such as but not limited to muscle spasms, joint arthropathies and tendinopathies. The mechanism of action focuses on increasing blood flow, increasing the extensibility of collagen fibers and facilitating local inflammatory effects.

Conclusion:

Multiple complimentary non-invasive modalities are currently available for clinical use to augment the treatment of painful musculoskeletal conditions and this review article illustrates four - Pulsed electromagnetic field therapy, Combined electrochemical therapy, Extracorporeal shockwave therapy and Short wave diathermy. More ongoing clinical studies are needed to help expand where the above technologies may be of use as a standalone or in concert with other modalities.

References: Odell, R. H., & Chaya, Z. (2016). Clinical outcomes utilizing the Combined Electrochemical Treatment for peripheral neuropathy: a retrospective study from a western clinic. Gavin J Anesthesiol, 2016, 1-7.

Auersperg, Vinzenz, and Klemens Trieb. "Extracorporeal shock wave therapy: an update." EFORT Open Reviews 5, no. 10 (2020): 584-592.