Spine fusion for discogenic low back pain: outcome in
patients treated with or without pulsed electromagnetic field
stimulation.
Beneficial effects of electromagnetic fields.
Therapeutic effects of pulsed magnetic fields on joint
diseases.
Modification of biological behavior of cells by Pulsing
Electromagnetic fields, (PMFT)
How can pulsed electromagnetic field therapy assist in the
healing of bones and ligaments?
Prevention of osteoporosis by pulsed electromagnetic
fields.
A double-blind trial of pulsed electromagnetic fields for
delayed union of tibial fractures.
A randomized double-blind prospective study of the efficacy
of pulsed electromagnetic fields for interbody lumbar fusions.
Spine fusion for discogenic low back pain: outcome
in patients treated with or without pulsed electromagnetic field
stimulation.
Sixty-one randomly selected patients who underwent lumbar fusion
surgeries for discogenic low back pain between 1987 and 1994 were
retrospectively studied. All patients had failed to respond to
preoperative conservative treatments. Forty-two patients received
adjunctive therapy with pulsed electromagnetic field (PEMF) stimulation,
and 19 patients received no electrical stimulation of any kind. Average
follow-up time was 15.6 months postoperatively. Fusion succeeded in
97.6% of the PEMF group and in 52.6% of the unstimulated group (P <
.001).
Marks RA. Richardson Orthopaedic Surgery, Texas,
USA.
Beneficial effects of electromagnetic fields.
Selective control of cell function by applying specifically configured,
weak, time-varying magnetic fields has added a new, exciting dimension
to biology and medicine. Field parameters for therapeutic, pulsed
electromagnetic field (PEMFs) were designed to induce voltages similar
to those produced, normally, during dynamic mechanical deformation of
connective tissues. As a result, a wide variety of challenging
musculoskeletal disorders have been treated successfully over the past
two decades. More than a quarter million patients with chronically
ununited fractures have benefitted, worldwide, from this surgically
non-invasive method, without risk, discomfort, or the high costs of
operative repair. Many of the athermal bioresponses, at the cellular and
subcellular levels, have been identified and found appropriate to
correct or modify the pathologic processes for which PEMFs have been
used. Not only is efficacy supported by these basic studies but by a
number of double-blind trials. As understanding of mechanisms expands,
specific requirements for field energetics are being defined and the
range of treatable ills broadened. These include nerve regeneration,
wound healing, graft behavior, diabetes, and myocardial and cerebral
ischemia (heartattack and stroke), among other conditions. Preliminary
data even suggest possible benefits in controlling malignancy.
Bassett C. Bioelectric Research Center, Columbia
University New York
Therapeutic effects of pulsed magnetic fields on
joint diseases.
The present paper describes the effects of pulsed magnetic fields (PMF)
on diseases of different joints, in chronic as well as acute conditions
where the presence of a phlogistic process is the rule. Optimal
parameters for PMF applications were sought at the beginning of the
study and then applied for 11 years; a technical modification in the PMF
generator was introduced 5 years ago to satisfy the requirement of a
hypothesis advanced to understand the mechanism of PMF treatment.
3,014 patients were treated by means of MF at extremely low frequencies
and intensities. Patient follow-up was pursued as constantly as
possible. Pain removal, recovery of joint mobility and maintenance of
the improved conditions represented the parameters for judging the
results as good or poor. The chi-square test was applied in order to
evaluate the probability that the results are not casual. A general
average value of 78.8% of good results and 21.2% of poor results was
obtained. Higher (82%) percentages of good results were observed when
single joint diseases were considered with respect to multiple joint
diseases (polyarthrosis); in the latter, the percentage of good results
was definitely lower (66%). The high percentage of good results obtained
and the absolute absence of both negative results and undesired
side-effects, together with the therapeutic advantage due to a technical
modification in the PMF generator, led to the conclusion that magnetic
field treatment is an excellent physical therapy in cases of joint
diseases. A hypothesis is advanced that external magnetic fields
influence trans-membrane ionic activity.
Riva Sanseverino, E. et.al. Universita di Bologna,
Italy.
Modification of biological behavior of cells by
Pulsing Electromagnetic fields, (PMFT)
On the major part of the calcified mass of adult bone there are no
changes in bone mass, however there is a part on which bone is being
formed and a part on which bone is being resorbed. Decalcification
occurs when bone resorption is greater than bone formation.
Bone formation comprises two steps, the laying down of the
extra-cellular matrix and the deposition therein of bone salts. The
dynamic processes of formation and destruction of bone are under
cellular control. Bone formation is controlled by single nuclear cells
called Osteoblasts, and bone resorption by multinuclear giant
cells are called Osteoclasts. Bone is a specialized connective
tissue, in which a matrix consisting of collagen fibers and a large
variety of other proteins and ground substance are impregnated with a
solid mineral. The bone matrix is responsible for the resistance of bone
to tractional and torsional forces. The collagen forms more than 25 % of
the bones and is synthesized by osteoblasts. On the bone surface
collagen fibers are normally arranged in concentric rings of hard
calcified matrix.
The bone minerals provide to the bone compressive strength and rigidity.
It contains the mineral salts hydroxyapatite and calcium. In addition
there are small amounts of magnesium hydroxide, fluoride and sulphate.
As these salts are deposited in the framework formed by the collagen
fibers of the matrix, crystallization occurs and the tissue hardens.
This process is called calcification or mineralisation. Both the
concentrations of ions of calcium and phosphate in the extracellular
fluid maintain crystallization. If the concentration is not adequate the
tissue will not be hard enough resulting in increased bone fracture
risk.
There are two types of bone structure. Cortical (compact) bone and
trabecular (spongy) bone. Cortical bone is more dense and constitutes of
80 % of the skeletal mass and forms the external layer of all bones in
the human body. Trabecular bone consists of lamellae arranged in an
irregular latticework of thin plates of bone and helps long bones to
resist the stress of weight placed on them.
The process by which bone forms is called ossification. Bone forms
either by the mineralisation of cartilage or directly by osteoblasts in
a collagenous matrix. During the first two decades of life bone grows,
followed by consolidation and reaching its peak value around thirty five
years. After this peak, bone loss starts. Nutritional factors,
especially calcium intake, the level of physical activity and generic
factors are important in determining the peak bone mass.
When a bone is fractured, it heals with bone. Bone is the only solid
tissue in the body that can replace itself. Bone healing is simple when
it occurs smoothly, complicated when it does not. The process is being
initiated by stimuli from the bone itself. Fractures through bone with a
good blood supply, surrounded by muscle and without soft tissue trauma,
have an excellent chance of healing, but fractures at the middle of long
bones, particularly with extensive soft tissue damage, have a high
incidence of non-union.
Selected low-energy time-varying electromagnetic fields have been used
during the past 15 years to treat un-united fractures (non-unions). More
than 100,000 patients, mainly in the USA, have been treated.
Retrospective studies have substantiated their biological effectiveness
in large numbers. Bone is responsive to the mechanical demands placed on
it. When loading diminishes, as it does during bed rest, immobilization
and weightlessness, bone mass is lost. On the other hand when loading is
increased correctly, bone mass increases.
Results of bio-mechanical and histologic investigations prove that
electromagnetic fields not only prevent bone loss, but also restores
bone mass, once lost. A program was set up at McGill University of
Montreal, where was found that electromagnetic fields damp bone
resorption activity. Furthermore prove was found that selected
electromagnetic fields increase bone formation.
The resorption of bone is lowest and formation of new bone greatest,
when energy of the imposed fields is concentrated in the lower frequency
components. These results are consistent with other studies showing,
that cells respond to a broad spectrum of frequencies. They appear to be
most sensitive to frequencies in the range of those produced
endogenously, that is in the range of 100 Hz or less.
Tissue dosimetry studies show that the frequency response of cortical
bone over a range of 100 Hz to 20 kHz show a steep roll off between 100
and 200 Hz.
Electromagnetic fields at specific frequencies have shown to produce
osteogenic effects in a turkey ulna model. Furthermore low-amplitude
signals decrease bone resorption in a canine fibular model. Lifestyle
factors like malnutrition, smoking, excessive use of alcohol and a
sedentary lifestyle contribute to, and worsen, osteoporosis. It is not
known whether this response derives from decreased osteoblastic
activity, increased osteoclastic resorption, or both. Elderly persons
can heal fractures in normal intervals, showing that osteoblasts can be
activated by appropriate stimuli.
A study at the University of Hawaii School of Medicine was designed to
provide concrete data on the restoration of bone mass in post-menopausal
females. A total of 20 subjects between 57 and 75 years, all with
decreased bone mineral density as defined by a bone densitometer, were
treated during a period of 12 weeks. After a period of 6 weeks the bone
density rose in those patients with an average of 5.6%.
Electromagnetic fields do modify biological behavior by inducing
electrical changes around and within the cell. The key to rational use
of electromagnetic fields lies in the ability to define the specific
treatment parameters (amplitude, frequency, orientation and
timing). Properly applied pulsed electromagnetic fields, if scaled
for whole body use, has clear clinical benefits in the treatment of
bone diseases and related pain, often caused by micro-fractures in
vertebrae. In addition, joint pain caused by worn out cartilage layers
can be treated successfully, through electromagnetic stimulation,
increasing the partial oxygen pressure and resulting in increased
calcium transport. Repair and growth of cartilage is thus stimulated,
preventing grinding of the bones.
Ben Philipson, Curatronic Ltd.
How can pulsed electromagnetic field therapy assist
in the healing of bones and ligaments?
Bone is essentially calcium structure which contains trace elements. One
particular element recently identified is Alpha Quartz. This is the same
type of material used in computers and digital or electronic watches.
When this material is compressed, it develops a voltage across its two
compressive faces, a phenomenon known as the piezoelectric effect. The
old crystal pickups on record players used this effect to generate
electrical sound signals. Gas appliances and some cigar lighters also
utilize the same effect to generate a spark for ignition.
In bone, areas of stress generate small electric charges which are
greater than those of less stressed areas, so that polarized bone-laying
cells (osteoblasts) are believed to be attracted to these areas and
begin to build up extra bone material to counter the stress.
With bone injuries, bleeding occurs to form a haematoma in which
capillaries quickly form, transporting enriched blood to the injury
site. Pulsed Magnetic Field therapy of a base frequency of 50Hz, pulsed
at above 12Hz, causes vasodilatation and capillary dilatation, so
helping to speed up the process of callus formation. Within the bone
itself, pulsed electromagnetism causes the induction of small eddy
currents in the trace elements, which in turn purify and strengthen the
crystal structures. These have the same effect as the stress-induced
voltages caused by the alpha quartz and as such, attract bone cells to
the area under treatment. This can, therefore, accelerate the bone
healing process to allow earlier mobilization and eventual full union.
Ligaments and tendons are affected in similar ways to solid bone by
pulsed electromagnetic therapy, since they are uncalcified bone
structures in themselves.
Dr. D. C. Laycock, Ph.D. Med. Eng. Westville
Consultants.
Prevention of osteoporosis by pulsed electromagnetic
fields.
Using an animal model, we examined the use of pulsed electromagnetic
fields, induced at a physiological frequency and intensity, to prevent
the osteoporosis that is concomitant with disuse. By protecting the left
ulnae of turkeys from functional loading, we noted a loss of bone of
13.0 per cent compared with the intact contralateral control ulnae over
an eight-week experimental period. Using a treatment regimen of one hour
per day of pulsed electromagnetic fields, we observed an osteogenic
dose-response to induced electrical power, with a maximum osteogenic
effect between 0.01 and 0.04 tesla per second. Pulse power levels of
more or less than these levels were less effective. The maximum
osteogenic response was obtained by a decrease in the level of
intracortical remodeling, inhibition of endosteal resorption, and
stimulation of both periosteal and endosteal new-bone formation. These
data suggest that short daily periods of exposure to appropriate
electromagnetic fields can beneficially influence the behavior of the
cell populations that are responsible for bone-remodeling and that there
is an effective window of induced electrical power in which bone mass
can be controlled in the absence of mechanical loading.
Rubin C. et.al. Dep. of Orthopaedics, State
University of New York J Bone Joint Surg Am
A double-blind trial of pulsed electromagnetic
fields for delayed union of tibial fractures.
A total of 45 tibial shaft fractures, all conservatively treated and
with union delayed for more than 16 but less than 32 weeks were entered
in a double-blind multi-centre trial. The fractures were selected for
their liability to delayed union by the presence of moderate or severe
displacement, angulation or comminution or a compound lesion with
moderate or severe injury to skin and soft tissues. Treatment was by
plaster immobilisation in all, with active electromagnetic stimulation
units in 20 patients and dummy control units in 25 patients for 12
weeks. Radiographs were assessed blindly and independently by a
radiologist and an orthopaedic surgeon. Statistical analysis showed the
treatment groups to be comparable except in their age distribution, but
age was not found to affect the outcome and the effect of treatment was
consistent for each age group. The radiologist's assessment of the
active group showed radiological union in five fractures, progress to
union in five but no progress to union in 10. In the control group there
was union in one fracture and progress towards union in one but no
progress in 23. Using Fisher's exact test, the results were very
significantly in favour of the active group (p = 0.002). The orthopaedic
surgeon's assessment showed union in nine fractures and absence of union
in 11 fractures in the active group. There was union in three fractures
and absence of union in 22 fractures in the control group. These results
were also significantly in favour of the active group (p = 0.02). It was
concluded that pulsed electromagnetic fields significantly influence
healing in tibial fractures with delayed union.
Sharrard WJ Royal Hallamshire Hospital, Sheffield,
England. J Bone Joint Surg
A randomized double-blind prospective study of the
efficacy of pulsed electromagnetic fields for interbody lumbar fusions.
A randomized double-blind prospective study of pulsed electromagnetic
fields for lumbar interbody fusions was performed on 195 subjects. There
were 98 subjects in the active group and 97 subjects in the placebo
group. A brace containing equipment to induce an electromagnetic field
was applied to patients undergoing interbody fusion in the active group,
and a sham brace was used in the control group. In the active group
there was a 92% success rate, while the control group had a 65% success
rate (P greater than 0.005). The effectiveness of bone graft stimulation
with the device is thus established.
Mooney V. Orthopaedic Surgery, University of
California Spine
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