Veterinary applications of pulsed electromagnetic field therapy

Gaynor, J. S., Hagberg, S., & Gurfein, B. T. (2018). Veterinary applications of pulsed electromagnetic field therapy. Research in Veterinary Science, 119, 1–8. https://doi.org/10.1016/j.rvsc.2018.05.005

What This Paper Covers: PEMF for Dogs

The review provides a historical overview of PEMF devices, outlines how they differ in waveform and intended use, and summarizes mechanisms of action and clinical evidence relevant to both human and veterinary care. The authors stress that PEMF is not a single therapy but a category of devices, with outcomes depending on waveform, frequency, and dosing.

How the Researchers Set the Stage

• Early electrotherapy used heat-generating diathermy machines; by the 1970s, fracture healing electrodes were replaced with non-invasive inductive coils.
• By the early 1980s, bone growth stimulators (BGS) were FDA-approved for treating non-union fractures. These devices use low-frequency waveforms and require long daily sessions.
• In the 1990s, shortwave, nonthermal PEMF devices were developed to address soft tissue inflammation and pain. These use a 27.12 MHz carrier wave, with shorter sessions.
• Targeted vs. non-targeted: targeted devices are engineered to activate specific biological cascades, while non-targeted devices vary in output and effectiveness.

Biological Mechanisms

• Faraday’s induction principle: pulsed magnetic fields induce tiny electric fields in tissue, which set off cellular signals.
• Calcium–calmodulin–nitric oxide pathway (core mechanism):
  • PEMF increases intracellular calcium, which binds calmodulin and activates nitric oxide synthase.
  • This produces short bursts of nitric oxide (NO), which raise cGMP levels.
  • The result: reduced inflammatory cytokines, vasodilation and better blood flow, and growth factor release that supports tissue regeneration.
• Why nitric oxide matters: The review highlights NO as a central repair signal, with roles in calming inflammation, protecting cells, and restoring circulation. The pathway activates only in injured tissue, which helps explain PEMF’s favorable safety record.
• Bone effects: PEMF also increases bone morphogenetic proteins (BMP-2/4), promotes osteoblast activity, and supports fracture healing.
• Other modulators: induction of heat shock proteins (linked to cell protection) and upregulation of adenosine receptors (linked to pain and inflammation reduction).

Evidence Reviewed

• Bone healing
  • Beagle tibial osteotomy: BGS accelerated recovery of weight-bearing and bone strength compared to sham.
  • Veterinary case reports suggest potential for conditions like Legg-Calvé-Perthes disease, but larger trials are needed.
• Osteoarthritis
  • Humans: targeted PEMF achieved greater pain reduction at much shorter daily doses than non-targeted devices (Table 2, page 3).
  • Dogs: PEMF reduced OA pain and lameness in small studies; one trial reported better long-term outcomes than firocoxib, though controls were limited.
• Post-operative pain, inflammation, and edema
  • Humans: targeted PEMF reduced pain, narcotic use, and IL-1β levels after breast surgery.
  • Dogs: in acute intervertebral disc extrusion surgery, targeted PEMF reduced incision pain, lowered inflammatory biomarkers, and improved recovery compared with sham.
• Wound healing
  • Chronic wounds in humans closed faster with PEMF; animal studies showed improved vascularization and flap survival, consistent with NO-mediated perfusion effects.

PEMF Devices and Dosing Considerations for Dogs

• Bone growth stimulators: low-frequency; require hours per day over months; strongest evidence for fracture repair.
• Shortwave, nonthermal devices: high-frequency; minutes per session; optimized for pain and soft tissue inflammation.
• Targeted vs. non-targeted: targeted devices efficiently engage NO pathways and achieve stronger results with shorter treatment times; outcomes are not interchangeable across devices.

Safety and Tolerance

The review reports over three million PEMF treatments delivered since the 1990s without significant adverse events. Because targeted PEMF effects occur only in injured tissues, treatment does not overstimulate healthy areas.

Limitations and Future Directions

Veterinary studies are often small, unblinded, or without sham controls. Device variability complicates generalization across brands. The authors call for randomized, blinded veterinary trials with clearly defined waveforms, doses, and endpoints.

Why This Matters for Dogs

PEMF therapy offers a safe, non-invasive option for dogs with arthritis, surgical recovery needs, or chronic pain. By leveraging nitric oxide signaling to calm inflammation and restore circulation, PEMF provides a drug-sparing tool that fits well in multimodal veterinary care. More rigorous veterinary research will help define best practices, but according to this review, current evidence supports PEMF as a valuable adjunct in canine health.