The ability to relieve pain is very variable and unpredictable, depending on the source or location of pain and whether it is acute or chronic. Pain mechanisms are complex and have peripheral and central nervous system aspects. Pain management should be tailored to the specifics of the pain process in the individual patient. Psychological issues have a very strong influence on whether and how pain is experienced and whether it will become chronic. Most effective pain management strategies require multiple concurrent approaches, especially for chronic pain. It is rare that a single modality solves the problem, but research shows pain management with PEMF or pulsed magnetic therapy to be promising.
PEMF accelerates the binding of calcium (Ca2+) to calmodulin (CaM), the process responsible for the body’s natural, anti-inflammatory nitric oxide (NO) cascade. NO is a key element in the body’s natural healing process. It is also a powerful vasodilator, increasing blood and lymphatic flow.
Additionally, NO down-regulates interleukin-1 beta (IL1β) and inducible nitric oxide synthase (iNOS), which leads to reduced cyclooxygenase-2 (COX-2) and prostaglandins – molecules responsible for causing inflammation and pain. Unlike other systemic COX-2 inhibitors such as nonsteroidal anti-inflammatory drugs (NSAIDs), the targeted PEMF signals stimulate localized reaction pathways, thereby reducing pain and inflammation in the knee without the risks and side effects associated with NSAIDs.
Magnetic fields affect pain perception in many different ways. These actions are both direct and indirect. Direct effects of magnetic fields are: neuron firing, calcium ion movement, membrane potentials, endorphin levels, nitric oxide, dopamine levels, acupuncture actions and nerve regeneration. Indirect benefits of magnetic fields on physiologic function are on: circulation, muscle, edema, tissue oxygen, inflammation, healing, prostaglandins, and cellular metabolism and cell energy levels.
Most studies on pain use subjective measures to quantitate baseline and outcome values. Subjective perception of pain using a visual analogue scale (VAS) and pain drawings is 95% sensitive and 88% specific for current pain in the neck and shoulders and thoracic spine.
Measured pain intensity (PI) changes with pain relief and satisfaction with pain management. Based on a numerical descriptor scale (NDS) and a visual analog scale (VAS), the average reduction in PI with medical treatment in an emergency room setting was 33%. A 5%, 30%, and 57% reduction in PI correlated with no, some/partial, and significant/complete relief. If initial PI scores were moderate/severe pain (NDS > 5), PI had to be reduced by 35% and 84%, to achieve some/partial and significant/complete relief, respectively. Patients in less pain (NDS < or = 5) needed 25% and 29% reductions in PI. However, relief of pain appears to only partially contribute to overall satisfaction with pain management.
Several authors have reviewed the experience with pulsed magnetotherapy (PEMF) in Eastern Europe and the west. PEMFs have been used extensively in many conditions and medical disciplines. They have been most effective in treating rheumatic disorders. PEMFs produced significant reduction of pain, improvement of spinal functions and reduction of paravertebral spasms. Although PEMFs have been proven to be a very powerful tool, they should always be considered in combination with other therapeutic procedures.
Certain pulsed electromagnetic fields (PEMF) affect the growth of bone and cartilage in vitro, with potential application as an arthritis treatment. PEMF stimulation is already a proven remedy for delayed fractures, with potential clinical application for osteoarthritis, osteonecrosis of bone, osteoporosis, and wound healing. Static magnets may provide temporary pain relief under certain circumstances.
The ability of PEMFs to affect pain is dependent on the ability of PEMFs to positively affect human physiologic or anatomic systems. Research is showing that the human nervous system is strongly affected by therapeutic PEMFs. Behavioral and physiologic responses of animals to static and extremely low frequency (ELF) magnetic fields are affected by the presence of light.
The best option
One of the most reproducible results of weak, extremely low-frequency (ELF) magnetic field (MF) exposure is an effect upon neurologic pain signal processing. Pulsed electromagnetic field (PEMFs) have been designed for use as a therapeutic agent for the treatment of chronic pain in humans. Recent evidence suggests that PEMFs would also be an effective complement for treating patients suffering from acute pain. Recent studies also suggest that magnetic field treatments involving the manipulation of standing balance would be effective in the determination of the etiology of chronic pain and hence be effective in the diagnosis of the underlying disease state. Static magnetic field devices with strong gradients have also been shown to have therapeutic potential. Specifically placed devices, such as the PEMF 4000, have been shown to reduce neural action potentials in vitro and alleviate spinal mediated pain in human subjects.
Human studies involving the induction of analgesia, whether utilizing pharmacology or magnetic field treatments, also need to account for the placebo response, which may explain as much as 40% of the analgesia response. However, the placebo response, or at least the central nervous system mechanisms responsible for the placebo response, may be an appropriate target for magnetic field induced therapies. Magnetic field manipulation of cognitive and behavioral processes has been well-documented in animal behavior studies and subjective-measure studies involving human subjects, which may also be one of the mechanisms of the use of PEMFs in managing pain.
Studies support PEMF’s effect on pain
Patients suffering from headache were treated with a PEMF over a 5-year period after failing acupuncture and medications. PEMF applied to the whole body, 20 min/day for 15 days were very effective for migraine, tension and cervical headaches at one month after treatment. They had at least a 50% reduction in frequency or intensity of the headaches and reduction in analgesic drug use. Poor results were observed in cluster and posttraumatic headache. Neuropathic pain syndrome (NPS) patients benefit from pulsed radiofrequency (PRF) treatment. Patients had severe left-sided sciatica and back pain, neuropathic pain in the anterior chest wall associated with removal of a tumor from the left pleural cavity, left-sided sciatica in a classical sacral root distribution and low back pain and left sided sciatica. All patients had been taking oral medications and had received repeated injections of local anesthetic agents and steroids with poor results. The patients were treated with a 300-kHz PRF. Treatments were applied to left L5 dorsal root ganglion (DRG) for 2 minutes, the spinal roots of the T2-T4 dermatomes and the left L5 DRG and S1 root and to the left L5 DRG, respectively. All patients experienced significant pain relief.
Treatment of persistent neck pain, studied in a double-blind, placebo-controlled trial, reduced pain and improved mobility with a low-power pulsed short wave 27 Hz diathermy system. The neck pain lasted longer than 8 weeks and was unresponsive to at least 1 course of nonsteroidal anti-inflammatory drugs. A soft cervical collar was fitted with a miniaturized, pulsed, short-wave diathermy generator. Each unit was powered by two 9-V batteries and had a frequency of 27 MHz. Treatments were for 3-6 weeks, 8 hr daily, analgesics could be used as needed and nonsteroidal anti-inflammatory drugs. 75% of the patients improved in range of motion and pain within 3 weeks of treatment.
Chronic pain is often accompanied with or results from decreased circulation or perfusion to the affected tissues, for example, cardiac angina or intermittent claudication. PEMFs have been shown to improve circulation. Skin infrared radiation increases due to immediate vasodilation with low frequency fields and increased cerebral blood perfusion in animals. Pain syndromes due to muscle tension and neuralgias also improved.
Another group having more than 20 years of experience of using magnetic or electromagnetic fields (EMF) in the treatment of about 1500 patients with trauma, musculoskeletal diseases, circulation and nervous system problems. They used various magnetic devices produced in Eastern Europe, including static magnetic fields (SMF), sinusoidal or PEMF extremely low-frequency fields (ELF EMF) and extremely high-frequency (EHF) EMFs ranging in field strength from 1-40 mT. Treatments lasted from 20-30 minutes per day, to 5-8 hr per day for up to 3-4 wk. The treatments had anti-pain, anti-edema, antiinflammatory, macro- and microcirculation benefits. The results of the treatment depended not only on the parameters of the fields but also on the individual sensitivity of the organism.
PEMFs can vary widely in frequencies, waveforms, harmonics and duty cycles. The most effective results in clinical use were found with extremely ultra-low frequency PEMFs.
Back pain is endemic in North America. Lumbar arthritis is a very common cause of back pain. 35-40 mT PEMFs, for 20 min daily for 20-25 days successfully treat back pain. This was shown in 220 patients and 60 controls. Relief or elimination of pain, improved rehabilitation and improvement of secondary neurologic symptoms. Continuous use over the treatment episode works best, in about 90-95% of the time. The control patients only showed a 30% improvement.
Chronic back pain treated for 2 to 12 years with PEMFs, which failed other treatment modalities, also improves. PEMF is used at the site of pain and related trigger points for 20 to 45 minutes as found in single and double blind studies, in patients from 41 to 82 yr of age. The field strengths were from 5 to 15 G in the frequency range from 7 Hz to 4 kHz. Pain elimination was measured by visual analogue scale (VAS) scale. The VAS value 0, no pain to 10, maximum pain is recorded before and after each treatment session. Some patients remain pain free 6 months after treatment. Some return to jobs they had been unable to perform. Short term effects are thought due to decrease in cortisol and noradrenaline and an increase serotonin, endorphins and enkephalins. Longer term effects may be due to a CNS, peripheral nervous system biochemical and neuronal effects in which correction of pain messages occurs and the pain is not just masked as in the case of medication.
Long term results
The benefits of PEMF use may last considerably longer than the time of use. In rats, a single exposure produces pain reduction both immediately after treatment and at 24 hrs after treatment. The analgesic effect is observed also at 7th and 14th day of repeated treatment and also at 7th day and 14th day after the last treatment.
High frequency PEMF over 10-15 single treatments every other day either eliminates or improves, even at 2 weeks following therapy, in 80% of patients with pelvic inflammatory disease, 89% with back pain, 40% with endometriosis, 80% with postoperative pain, and 83% with lower abdominal pain of unknown cause.
Post-herpetic neuralgia (PHN), a very common and painful condition, which is often medically-resistant, responds to pulsed magnetic field (PEMF) and whole body AC magnetic field (ACMF) stimulation. PEMF therapy was for 20-30 minutes daily for 19 treatments over 34 days and ACMF therapy 30 minutes daily for 38 treatments over 85 days. The PEMF was a 4-16 Hz and 0.6-T samarium/cobalt magnet system surrounded by spiral coil pads with a maximum 0.1-T pulse at 8 Hz. The pads were pasted on the pain/paresthesia areas. The ACMF treatment bed consisted of 19 electrodes containing paired coils producing 0.08 T sine wave pulses. Three electrodes were applied to the head region, 3 to the thoracoabdominal region, 4 to the dorsolumbar region, 6 to the upper limbs, and 3 to the lower limbs. Both treatments continued until symptoms improved or an adverse side effect occurred. Pain was rated on a 10 point VAS scale and paresthesia on a 5 point scale. Outcomes were also evaluated clinically with infrared thermography and Doppler ultrasonography to assess blood flow. PEMF therapy was effective in 80%. No pain was made worse. ACMF therapy was effective in 73%. The average pain score following the first treatment was better for PEMF vs ACMF.
Results obtained to date with PEMF therapy in animal models and clinical human studies suggest that this type of treatment can reduce edema, but only during treatment sessions. PRF applied for 20-30 min causes a significant decrease in edema lasting several hours. PRF seems to affect sympathetic outflow, inducing vasoconstriction, which in turn restricts movement of blood constituents that promote edema from vascular to extravascular components at the injury site. The passage of electrical current through the tissue displaces negatively charged plasma proteins normally found in the interstitium of traumatized tissue. This increased mobility could accelerate protein uptake by lymphatic capillaries, thereby increasing lymphatic flow, an established mechanism for extracellular fluid uptake. Each pathological stage in an injury may require different PRF parameters for optimal effects. PRFs promote healing of soft tissue injuries by reducing edema and increasing the rate of reabsorption of hematomas.
PEMFs can vary widely in frequencies, waveforms, harmonics and duty cycles. The most effective results in clinical use to treat pain were found with extremely ultra-low frequency PEMFs.