Baylor University Medical StudyTable of contents Introduction Method Results Discussion Conclusion References ABSTRACT. Vallbona C, Hazlewood CF, Jurida G. Response of pain to static magnetic fields in postpolio patients: a double blind pilot study. Arch Phys Med Rehabil 1997; 78: 1200-3.
Objective: To determine if the chronic pain frequently pre- sented
by postpolio patients can be relieved by application of magnetic fields
applied directly over an identified pain trigger point.
©1997 by the American Congress of Rehabilitalion Medicine and the American Academy of Physical Medicine and Rehabilitation POSTPOLIO
SYNDROME is a well-recognized clinical entity which, since the early 1980s,
has generated an abundant scientific literature (a Medline search found
88 references from 1981 to 1996; 24 of the publications included pain as
a key word). The clinical manifestations are either very specific (eg.
increasing muscle weakness on previously affected or unaffected muscles,
muscle fasciculations) or somewhat unspecific (eg, fatigue, pain).
|
|
The muscular type of pain can be objectively elicited by palpation of the
reported sore muscles and by identifying specific trigger points associated
with tlie referred pain. The atlas of trigger points provided by Travell
and Simons6,7 is of
great aid in the search for such trigger points. Symptomatic cervical arthritis
may be accompanied by a considerable degree of tight ness of the neck muscles
with trigger points in the sternocleidomastoid, scalenus, and trapezius
areas.
Regardless of the type of pain, postpolio patients have increased sensitivity to nociceptive stimuli,8 and this may explain why they report pain so often. In spite of its prevalence the available treatment for it is limited. Currently, recommended modes of treatmcnt are rest; traditional modalities of physical therapy (heat, cold, ultrasound, transcutaneous electrical neural stimulation [TENS] ); use of a support brace; or administrationof muscle relaxants, analgesics, or anti-inflammatory agents. The effectiveness of pharmacologic agents is generally poor, and in some instances (eg. use of aspirin or nonsteroidal anti- inflammatory drugs) there arc undesirable side effects. Other modalities of pain management such as meditation, yoga, or hypnosis have not given our patients consistent relief. The limited success in pain managementt prompted us to explore alternative methods of pain management. Static and fluctuating electromagnetic fields have been applied with apparent success for the management of pain in a variety of orthopedic conditions, most commonly traumatic bone fractures or surgical osteotomies.9-11 As early as 1938, Hansen12 reported the effectiveness of electromagnetic fields (which had "a carrying power of from 8.5 to 14 kg") applied for l to 15 minutes. Twenty- three of 26 patients with complaints of "sciatica," "lumbago," and "arthralgia" reported rapid and significant relief of their pain. The study was not double-blinded, but the author reported no pain reduction in two patients to whom the electromagnetic device was applied without the electricity being turned on. In osteoarthritis, double-blind, placebo-control studies have shown the efficacy of a pulsed electromagnetic field.13,14 Carpenter and Ayrapetyan15 provide an excellent overview of the biological effects of electromagnetic fields. The literature continues to grow from earlier reports,16-18 building on futtlier efforts to Scientifically document the impact of magnetic fields on bioiogical systems.19-22 The safety of application of these electromagnetic __________
fields
is attested by the World Health Organiiation,23
which reported: "The available evidence indicates the absence of any adverse
effects on human health due to exposure to static mag- netic fields up
to two Tesla" (2T = 20,000 Gauss).
We recruited 50 patients with postpolio syndrome who reported muscular or arthritic pain and who consented to participate in the study. The diagnosis of the postpolio syndrome was made according to well-established criteria.5, 26 |
|
Table 1 shows the characteristics of the study participants. There was
no significant difference in any of the variables that described the two
groups. There was a much greater proportion of women than men in both groups
(the women-to-men ratio of the participants in the study is 'slightly higher
than the rat for our clinic's population).
The race-ethnicity distribution
of the participants parallels that of the postpolio clinic patients. The
age of onset of poliomyelitis and the age of onset of the postpolio syndrome
were almost identical in both groups. Since the time of onset of thc postpolio
syndrome cannot always be clearly established, the data in the table should
be considered estimates only. The classification of the type of pain as
predominantly muscular or predominantly arthritic is somewhat arbitrary
because arthritic changes are often accompanied by muscular spasm with
clearly distinguishable trigger points. An distribution of the location
of pain where the active or inactive magnetic devices were applied did
not show any signiffcant difference between the two groups. The sacroiliac
joint was the most common location for both group (41% of those who received
the magnetized device and 33% of those who received the inactive device).
Table 2: Pretreatment and Posttreatment Pain Scores The
pretreatment score was almost identical in both groups of subjects, but
there was a highly significant difference between pre-treatment and posttreatment
scores in the two groups. Those who received the active device reported
much less pain than those who had the inactive device.
This
difference is highly significant (p < .0001). Also, the average score
decrease in the four patients who had a placebo effect was 4 points versus
7 for those who had a treatment effect.
The results of this randomized pilot clinical trial show that static magnetic fields of an intensily of 300 to 500 Gauss are effective in the control of pain in patients with the posipolio syndrome. Whether the pain was of a myofascial or arthritic nature, it seemed to respond equally well to the static magnetic field and the effect was noticed within 45 minutes from the onset of the application. |
|
We must point out that we studied the effect of the static magnetic fields in one painful area only on each subject and did not attempt to quantify the potential impact of such field on other painful areas that may have been present on the same patient. Interestingly, some patients recorded benefit derived from the magnetic field in other areas. This effect was reported mostly in the patients who had pain in both sacroiliac joints, in which case we always applied the device on the one that was most sensitive to palpation. The intensity of the applied magnetic fields was rather low in relation to that applied in other studies, and we did not attempt to assess a dose-response effect. It is likely that the level of penetration of the magnetic field is related not only to the magnet's intensity, but also to the distance between the superficial area to which the device is applied and the site of the trigger point that lies on the fascial plane of a muscle, tendon, or joint. Because of this, we excluded from the study very obese patients or those who had a significant amount of subcutaneous fat overlying the trigger point associated with the painful area. The fact that Hong22 did not find evidence of effect in his double-blind study of a loose magnet necklace may be due to the small delivered magntic intensity of the device, which was not directly applied over specific pain trigger points. We cannot explain the significant and quick pain relief reported by our study patients. The effect could result from a local or direct change in pain receptors, but it is also possible that there was an indirect central response in pain perception at the cerebral cortical or subcortical areas, or a change in the release of enkephalins at the reticular system. If the magnetic fields have an impact on the subcortical level of the brain, it is possible that the application of one magnetic device in one painful area may benefit to a greater or lesser extent the pain elicited in other trigger points This is an issue that requires further study. Bruno and colleagues8 have pointed out the existence of lesions in various areas of the brain of poliomyelitis survivors, and they believe that these lesions may explain the hypersensitive response to painful stimuli that they have observed in postpolio patients. This should not be interpreted to mean that the relief of pain produced by magnetic fields that we observed was specific for postpolio patients because similar responses to magnetic fields have been reported in patienis without known lesions of the central nervous system.12 Even so, our understanding of pain and pain relief is far from complete. Insofar as we can determine from the literatune, this double-blind placebo-controlled study using permanent magnets in a bipolar configuration directly applied to trigger points may be the first reported. This study coincides with mounting evidence that magnetic fields interact in significant ways with biological tissues. The exact mechanisms of the interaction of magnetic fields with biological tissues resulting in functional changes are unknown.28, 29 This is particularly true for our understanding of the pain relief associated with the application of a magnetic field to trigger points as demonstrated in this study. Much progress, however, is being made in the field of bioelectromagnetics, in both the experimental studies and theoretical concepts. Several of these concepts (some old and some new) appear to30-35 be promising; certainly. they are ultimately testable. We are interested in the possible role of water in the pain mechanism, and attempts will be made to evaluate the physical basis of this idea using magnetic resonance technology. It is now clear that water is organized in space and time,36 and in a human study conducted by onc of us (C.H.),37 subjective pain relief was associated with a shift of T-cells into the S-phase. Beall and colleagues38 demonstrated cyclical changes in the physical state(s) of water with the water being most organized in the S-phase. That water plays a major role in explaining the therapeutic effects of magnetic fields has also been proposed by others.15 The fact that none of our patients reported any discomfort resulting from the use of magnetic devices and that no comp- lications have been reported in the literature supports the notion that low-intensity magnetic fields produced by permanent magnets or electromagnetic devices are biologically safe.
The delivery of static magnetic fields through a magnatized device directly
applied to a pain trigger point or to a localized painful area results
in significant relief of pain within a short period of time (less than
45 minutes in our study) and with no apparent side effects. Based on the
results of this study and reports in the literature of the effect on people
with arthritis, it appears that magnetic field energy may he useful in
the management of pain in individuals with other types of impairments that
are commonly treated in primary care settings.
|
|
Acknowledments: The authors are indebted to Valory Pavlik, PhD, for her assistance in the study design, the statistical analysis of the results, and the review of the manuscript. Mandy Smith, PT, contributed to the selection of patients. Mrs Christine Toronjo was responsible for the oricessing of data. 1. Smith LK, Mabry M. Part one: poliomyclitis and the post-polio syndrome. In: Umphred D, editor. Neurological rehabilitation. 3rd ed. St. Louis (MO): C.V. Mosby Co.; 1995. p. 571-87. 2. Halstead LS, Wiechers DO, Rossi CR. Late effects of poliomyelitis: a national survey. In: Halstead LS, Wiechers DO, editors. Late effects of poliomyelitis. Miami: Symposia Foundation; 1985. p.11 - 31. 3. Agre JC. The role of exercise in the patient with post-polio syn- drome. Ann N Y Acad Sci 1995;753:321-34. 4. Jubelt B, Drucker J. Post-polio syndrome: an update. Semin Neurol 1993; 13:283-90. 5. Maynard FM. Managing the late effects of polio from a life-course perspective. Ann N Y Acad Sci l995;753:3-60. 6. Travell JG, Simons DG. Myofascial pain and dysfunction: the trig- er point manual, vol 1: the upper extremities. Baltimore (MD): Williams and Wilkins 1983. 7. Travell JG, Simons DG. Myofascial pain and dysfunction: The trigger point manual, vol 2: the lower extremities. Baltimore (MD): Williams and Wilkins; 1992. 8. Bruno RL, Frick NM, Cohen J. Polioencephalitis, stress, and the etiology of post-polio sequelae Orthopedics 1991;14:1269-76. 9. Becker RO. Cross currents. New York: The Putnam Publishing Group; 1990. 10.Becker RO, Selden G. The body electric: electromagnetism and the foundation of life. New York: William Morrow and Company; 1985. 11. Miner WK Markoll R. A double blind trial of the clinical effects of pulsed electromagnetic fields in osteoarthritis. J Rheumatol 1993; 20:456-60. 12. Hansen KM. Some observations with a view to possible influence of magnetism upon the human organism. Acta Med Scand 1938; 97:339-64. 13. Bassett A. Therapeutic uses of electric and magnetic fields in ortho- pedics. In: Carpenter DO, Ayrapetyan S, editors. Biological effects of electric and magnetic fields, vol 2: beneficial and harmful effects. San Diego: Academic Press 1994. p. 13-48. 14. Trock DH, Bollet AJ, Markoll R. The effect of pulsed electromag- netic fields in the treatment of osteoarthritis of the knee and cervical spine. Report of randomized, double blind, placebo controlled trials. J Rheumatol 1994;21:1903-11. 15. Carpenter DO, Ayrapetyan S, editors. Biological effects of electric and magnetic fields. San Diego: Academic Press; 1994. 16. Tenforde TS, editor. Magnetic field effect on biological systems. Based on die Proceedings of the Biomagnetic Effects Workshop held at Lawrence Berkeley Laboratory, University of California, April 6-7 1978. New York: Plenum Publishing Corporation; 1979. Ms 17. Adey WR, Chopart A. Cell surface ionic phenomena in brane signaling to intracellular enzyme systems. In: Blank M, Findl E, editors. Mechanistic approaches to interactions of electromagnetic fields with living systems. New York: Plenum Press; 1987.p. 365-87. 18. Adey WR. Tissue interactions with non-ionizing electromagnetic fields. Physiol Rev 1981;61:435-514. 19. Hong CZ, Lin JC, Bender LF, Schaeffer JN, Meltzer RJ, Causin P. Magnetic necklace: its therapeutic effectiveness on neck and shoulder pain. Arch Phys Med Rehabil 1982;63:462-6. 20. Hong CZ, Harmon D, Yu J. Static magnetic field influence on rat tail nerve function. Arch Phys Med Rehabil 1986;67:746-9. 21. Hong CZ. Static magnetic field influence on human nerve function. Arch Phys Med Rehabil 1987;68:162-4. |
|
22. Itegin M, Gunay I, Logoglu G, Isbir T. Effects of static magnetic field on specific adenosine-5'-triphosphatase activities and bioelectrical and biomechanical properties in the rat diaphragm muscle. Bioelectromagnetics 1995; 16:117-51. 23. World Health Organization. Magnetic fields. United Nations Environment Programme, The International Labor Organization. Geneva: WHO; 1987. 24. Davis A, Rawls WC. The magnetic effect. Hicksville(NY): Exposition Press; 1974. 25. Nakagawa K. Study on clinical effects of the magnetic necklace. In: TDK Magneto Medical Publication Series 1. Beverly Hills (CA): 1975. p.1-12. 26. Dalakas MC. The post-polio syndrome as an evolved clinical entity. Definition and clinical description. Ann N Y Acad Sci 1995;753:68-80. 27. Melzack R. The McGill Pain Questionnaire: major properties and scoring methods. Pain 1975;l:277-99. 28. Blank M, Findl E, editors. Mechanistic approaches to interactions of electric and electromagnetic fields with living systems. New York: Plenum Press; 1987. 29. Ayrapetyan S, Avanesian A, Avetisian T, Majinian S. Physiological effects of magnetic fields may be mediated through actions of the state of calcium ions in solution. In: Carpenter DO, Ayrapetyan S, editors. Biological effects of electric and magnetic fields, vol 1- sources and mechanisms. San Diego: Academic Press; 1994. p. 181-92. 30. Cope FW. On the relativity and uncertainty of electromagnetic energy measurement at a superconductive boundary. Applicatio to perception of weak magnetic fields by living systems. Physiol Chem Phys l981;13:231-9. 31. Nordenstrbm BEW. Biologically closed electric circuits, clinical, experimental and theoretical evidence for an additional circulatory system. Stockholm: Nordic Medical Publications; 1983. 32. Liboff AR. The "cyclotron resonance" hypothesis: experimental evidence and theoretical constraints. In: Norden B, Ramel C, editors. Interaction mechanisms of low-level electromagnetic fields in living systems. New York: Oxford University Press; 1992. p.130-47. 33. Jacobson JI, Yamanashi WS. A possible physical mechanism in the treatment of neurologic disorders with externally applied pico tesla magnetic fields. Physiol Chem Phys Med NMR 1994;26:287-97. 34. Blanchard JP, Blackman CP. Clarification and application of an ion parametric resonance model for magnetic field interactions with biological systems. Bioelectromagnetics 1994; 15:217-38. 35. Lednev VV. Possible mechanism for the influence of weak magnetic fields on biological systems. Bioelectromagnetics 1991;12:71-5. 36. Ling GN. A revolution in the physiology of the living cell. Malabor (FL): Krieger Publishing Company; 1992. 37. Hazlewood CF, VanZandt RL. A hypothesis defining an objective end point for the relief of chronic pain. Med Hypotheses 1995;44: 63-5. 38. Beall PT, Hazlewood CF, Rao PN. Nuclear magnetic resonance patterns of intracellular water as a function of Hela cell cycle. Science 1976;192:904-7. |