Volume 2, Number 1 | Spring 2007

Japanese Acupuncture - Current Research
Clinical Study of Low Frequency Electroacupuncture
Therapy (EAT) for Treatment of Cervical Radiculopathy
Tomomi Sakai1), Fumiko Yasuno2)
1) Department of Health Courses on Acupuncture andMoxibustion, Faculty of Health Sciences
Tsukuba University of Technology, Ibaraki-ken, Japan2) Genki Plaza Medical Center for Health CareKey

words:

cervicalradiculopathy,

acupuncture,muscle EAT, nerve EAT

I. Introduction
Low frequency electroacupuncture, where theinserted needles are used as electrodes, is a treatment
form using low frequency electrical stimulation, and assuch, one variant of acupuncture therapy. Currently,
low frequency electroacupuncture is most frequently
used in clinics for diseases and symptoms in the fieldof orthopedics and here, in particular, nerve pulse
treatment has in recent years found wide
application1,2,3,4,5).
Originally,lowfrequency
electroacupuncture based on muscle pulse therapy,
was used for these diseases and symptoms. For
conditions in which muscle pulse therapy remained
ineffective, the application of electroacupuncture on
the damaged nerves reportedly resulted in
improvements of the symptoms3), so that this nerve
pulse therapy was proposed to be effective and thus
started to come into general use. When low frequency
electroacupuncture is performed in daily clinicalpractice, muscle pulse therapy is usually thetreatment of first choice based on the degree ofdifficulty of the needling. In case the muscle pulse
therapy is ineffective, the method is switched to thenerve pulse therapy. However, this decision is largely
based on experience and it is thus desirable to provide
constant evaluation criteria for the decision.
Yet, there have been no reports examining theclinical aspects of both muscle pulse therapy and nerve
pulse therapy. We have investigated the clinicaleffects of both muscle pulse therapy and nerve pulse
therapy in the treatment of patients with cervical
radiculopathies.

1) Materials
Subjects of the study were 41 patients diagnosed
with cervical radiculopathy based on their subjective
symptoms, positive findings of the physicalexamination as well as x-p and MRI findings. In thepatients with cervical radiculopathies included in thisstudy, head compression tests like the Jackson or
Spurling tests reproduced the pain in the arm.
Patients who had loss of muscle power, weakened
tendon reflexes, dysaesthesias and similar neurologic
anomalies were observed. Those in whom the headcompression test was negative, or who presented only
neck pain, were excluded from the study.
2) Selection criteria for either muscle pulse therapy or
nerve pulse therapy during the application of low
frequency electroacupuncture
The first choice of treatment for all 41 patients wasmuscle pulse therapy. In patients in whom the painscore dropped to less than 5 points after one month ofcontinuous treatment (10-point system),musclepulse therapy was continued (muscle pulse therapy
group). Yet, for patients in whom the pain score
improved only down to 6 points, the therapy was
switched to nerve pulse therapy and then continued(nerve pulse therapy transition group). The consent of
the patients was obtained for the switchover from themuscle pulse therapy to the nerve pulse therapy.
As a result, in the end the muscle pulse therapy
group included 24 and the nerve pulse therapytransition group 17 patients. No significant differences
regarding patient age or duration of morbidity among
the groups were observed. Table 1 shows the profiles
for both groups.
Muscle-EAT n=24

Nerve-EAT n=17

Sexmale 15, female 9

male 11, female 6Age51.6±10.848.3±9.2

Duration (days)

99.9±152.871.5±88.5

Head compression test

24

17

Sensory disturbance87Muscle weakness

50Abnormality in

4

1

deep tendon reflex

II. Materials and Methods

2

Table 1: Profile of the patients
The Journal of Kampo, Acupuncture and Integrative Medicine (KAIM)

Volume 2, Number 1 | Spring 2007

3) Low frequency electroacupuncture for the treatment

confirmation of the induction of mild contractions ofof cervical radiculopathy

the thumb the position of the needle tip was

In order to apply low frequency electroacupuncture

ascertained through CT imaging. Based on the results,

for the treatment of cervical radiculopathy, the level ofEbraheim8) classified three compartments of the sulcus

the responsible lesion was determined based on thefor the spinal nerve root (medial, central and lateralsubjective symptoms as well as the findings of physicalcompartment), according to which the needle tip can

examination and diagnostic imaging. The treatmentbewas then performed with the purpose of achieving acompartment of the exit of the intervertebral foramen.

change inmuscle tension and circulation in the

For the low frequency electrical stimulation used forvicinity of the affected nerve root. Regarding thisthe muscle and nerve pulse therapies, a frequency of 1

therapy, the muscle pulse therapy consisting of

Hz was used and applied over a period of 15 minutes.

needling the spaces between the spinous processes

Treatment frequency was one to two times per week.

confirmed

tobepositioned

in

the

lateraldirectly lateral and superior to the level of the affected
nerve root as well as choosing distal points on theaffected side, using the needles as electrodes for theapplication of a low frequency electrical stimulation,
has also been called the "acupuncture anesthesia
method”6). For example, during application of anelectric current to needles placed immediately lateraland inferior to the 5th cervical spinous process and thepoint Gokoku (Hegu, LI4) between the thumb andindex finger for stimulation of the sixth cervical nerve,mild muscle contractions of the fingers of the handwere observed (Fig. 1-A). For the nerve pulse therapy,
the needles are inserted into close proximity of thenerve root and then used as electrodes for theapplication of a low frequency electrical stimulation(Fig.1-B). Needles with a length of 50 mm and adiameter of 0.2 mm (Japanese-made 1 sun 3 bu, No.3
needles) were used. For the nerve pulse therapy7) the
needles were inserted in the same way as for themuscle pulse therapy into the spaces between thetransverse processes with another needle (needle
serving as an indifferent electrode). After obtainingreferred pain within the region of the innervation of
the particular nerve root, current was applied to theneedle inserted in the neck. The current was applied,
after confirming, that mild contractions of theperipheral muscles innervated by that nerve wereobserved.
Figures 2-A, B show needling of what wasconsidered to be the region of the nerve root C6,
applying a low frequency current of 1 Hz and after

The Journal of Kampo, Acupuncture and Integrative Medicine (KAIM)

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Volume 2, Number 1 | Spring 2007

and after 3 months to 16.9±1.1 points, indicating a4) Evaluation
Evaluation of the acupuncture treatment forsignificant improvement between the initial test andradiculopathy follows the evaluation criteria for thethetherapeutic

cervicalexamination of the differences between the groups

radiculopathies9) proposed by Tanaka et al. of Tohoku

showed that while no significant difference was

University, evaluating the condition monthly from theobserved in the test results at the first visit, relevant

first visit until after the third month. The evaluation

significant changes (p<0.05) were observed after one

criteria proposed by Tanaka et al. comprise a totalmonth. However, after 3 months

score of 20 points, including the following four items:changes were observed. In other words, 1 month after

subjective symptoms (0-8 points), ability to work or do

initiation of the treatment in the muscle pulse therapy

household chores (0-3 points), functions of the handgroup and nerve pulse therapy transition group, a(-2-0 points), objective symptoms (0-8 points).

difference in therapeutic results was observed, that

resultsoftreatment

for

test

after

3

months(p<0.05).

Subsequentno significant

considerdisappeared again after 3 months of treatment, so that

improvement of the subjective symptoms in patients

after 3 months the same therapeutic effects werewith radiculopathies to be very important15), theseobtained in both groups.

Moreover,since

Tanakaetal.

were also evaluated with a pain score.
2) Variations in the pain score
Fig. 4 shows the variations in the pain score. In all

Statistical processing
The Mann-Whitney U-test was used for the testing

patients the average pain score after 1 month wasof group differences, while the Bonferroni/Dunn

5.2±2.5 points and thus showed a significant (p<0,05)

method was used for the analysis of the values

improvement over the score at the first visit. Yet, if

obtained at the initial stage and at each following

both groups were examined separately, the score in theexamination for a multiple comparison test. Stat View

muscle pulse therapy group was 3.5±1.6 points and in

4.5 was used as the statistical software and the level ofthe nerve pulse therapy transition group 6.8±1.0

significance defined as p<0.05, p<0.01.

points. Improvement in the nerve pulse therapytransition group when compared to the muscle pulse

III. Results

therapy group was not as significant. A significant

1) Evaluation based on the evaluation criteria for thedifference (p<0,05) was observed between the twotherapeuticgroups. Although after one month of continuous

resultsoftreatmentforcervicaltherapy in the nerve pulse therapy transition group,

radiculopathies
Fig. 3 shows the results of muscle pulse therapy

an effective improvement had been achieved by theand nerve pulse therapy obtained from the initial visit

muscle pulse therapy as described above. In the groupuntil after the third month based on the evaluation

switched to the nerve pulse therapy the score after one

criteria for the therapeutic results of treatment formonth was naturally higher than in the muscle pulse

cervical radiculopathies. The figure shows, that in thetherapy group. Yet, one month after switching to themuscle pulse therapy group, the score at the first visit

nerve pulse therapy, that means 2 months after thewas 10.7±2.0 points (mean ± standard deviation), after

first visit, the pain score in the muscle pulse therapy

1 month the score improved to 15.0±1.9 points andgroup was 2.6±2.0 points and in the nerve pulse

after 3 months to 16.9±1.1 points (p<0.05). On thetherapy transition group 3.7±2.1 points, indicating aother hand, in the nerve pulse therapy transition

reduction in the difference between the two groups.

group, the score at the first visit was 10.1±1.7 points,

After three months (that is two months after switchingafter 1 month the score improved to 12.3±2.6 points

to the nerve pulse therapy) the score in the muscle

4

The Journal of Kampo, Acupuncture and Integrative Medicine (KAIM)

Volume 2, Number 1 | Spring 2007

pulse therapy group was 2.0±2.1 points and in thethan those observed by Tanaka et al. Moreover,nerve pulse therapy transition group 2.2±1.7 points,

Tanaka et al.10) observed among their cases withindicating that in both groups the same effect had beenradiculopathy,

achieved.

dysaesthesias, loss of muscle power and decreased
tendonIV. Discussionareflexes,

high

ratio

reportingaofpatients

ratio

of

with

86%

of

dysaesthesia, 69% of loss of muscle power and 67%

Tanaka et al.9) used their own evaluation criteria

decreased tendon reflexes respectively among theirfor the therapeutic results to examine the effects of300

conservative therapy in 43 patients with cervicaldysaesthesias were found in as few as 15 (37%) out ofradiculopathies. The results showed a score of 6.0

the 41 cases included in this study, loss of muscle

points at the first visit, that reportedly increased after

power in 5 patients (12%) and decreased tendon

three months of treatment to 11.9 points and after 4

reflexes also only in 5 patients (12%), revealing thatmonths to 13.1 points. Yet, for patients who had 4

the neurologic findings too were of lesser severity thanmonths of treatment and a score of less than 8 points

those reported by Tanaka et al. Based on thesecontinued

not befindings a comparison with the results of the

expected to result in a subsequent favorable outcome.

conservative treatment implemented by Tanaka et al.

The authors stated that for patients with scores

was considered to show that the results of the low

ranging between 9-13 surgery could also be considered.

frequency electroacupuncture were better.

conservative treatment, could

patients

withradiculopathies.

In

contrast,

Regarding the effects of the muscle pulse therapy
We investigated the therapeutic results obtained

and the nerve pulse therapy, examination of the painwith low frequency electroacupuncture based on thescore revealed that the score after one month ofevaluation criteria of Tanaka et al. and found in thetreatment

muscle pulse therapy group after 3 months an

3.5±2.2 points and in the nerve pulse therapy

improvement of the score to 16.9 points and in thetransition group 6.2±1.8 points. At this point in time anerve pulse therapy transition group to 15.9 points.

significant difference between the two groups was

The condition could be regarded as having improved so

observed, showing a clearly higher score in the nerve

far that surgery was not necessary. Yet, looking at thepulse therapy transition group. In other words, thescore at the first visit showed that Tanaka et al.

score difference between the groups shows that inpatients had a score of 6.0, while the patients of thepatients with higher scores, the treatment wasmuscle pulse therapy group in this study had a score ofswitched from the muscle pulse therapy to the nerve

10.7 points and in the nerve pulse therapy transition

pulse therapy, rendering these results inevitable. Yet,group of 10.1 points. While Tanaka et al. excluded

after 3 months of treatment, significant differences

patients, who underwent treatment at other medical

between the muscle pulse therapy group and the nerve

facilities, and included only those in whom thepulse therapy transition group were no longer

condition had developed within the last 2 months, theobserved. These findings suggest that the condition inpresent study also included patients in whom thepatients who showed resistance towards muscle pulse

condition had lasted longer than 2 months and whotherapy, may be improved by nerve pulse therapy. The

were treated otherwise prior to the treatment with low

same thing may be said about the application of

frequency electroacupuncture. The difference in theevaluation criteria for the therapeutic results.

in the muscle pulse therapy group wasscore at the first visit probably reflects these

Regarding the mechanism of onset of root pain,

circumstances. In either case, the patients included

Hirabayashi11) suggested, that it may be due toin this study were presented with milder conditions

mechanicalstimulation

The Journal of Kampo, Acupuncture and Integrative Medicine (KAIM)(pressure+friction)→5Volume 2, Number 1 | Spring 2007

radiculitis.

one of the mechanisms, namely the improvement ofMoreover, the nerve roots together with the ganglia

the nerve blood flow, is related to the alleviation of theare said to be characterized by their high vascularsymptoms. There are no reports dealing with low

permeability, so that the influence of circulatory

frequency electroacupuncture induced variations in

disturbances on nerve and connective tissues may

nerve

elicit edema induced swelling of the nerve fibers.

experiments the low frequency electroacupuncture

These lesions may then lower the stimulation

stimulation of nerves reportedly led to a significant

threshold so that even minimal stimuli will elicit pain.

improvement of the nerve blood flow16,17). Moreover,Also, Kobayashi et al.12,13) created in animal (dogs)

Kasuya4) and Inoue5) et al. reported that application ofexperiments a model of the pathology of entrapment

low frequency electroacupuncture to the nerves orneuropathy and observed lesions of the nerve roots.

nerve roots to be effective for the improvement of

The results showed a marked decrease in radicularrefractory pain and numbness caused by lumbar spinal

blood flow and conductivity in association withcanal stenosis. Regarding this mechanism, the authors

mechanical compression, making it clear that edema

agree with Inoue et al., who mentioned the increased

develops within the roots. Moreover, stagnation of

nerve blood flow.

circulatory

disturbances(edema)

→

blood

flow

in

humans,butinanimalintraaxonal flow and accumulation of SP (substance P)

Concerning the use of muscle pulse therapy andand CGRP in primary afferent fibers were observed

nerve pulse therapy based on the above describedand disturbances of the axoplasmic flow reported. The

results, the application of muscle pulse therapy incapillaries of the nerve root are innervated by nerve

cases

fibers containing SP and various other types of nerve

treatment stage, and if this did not produce certain

activating substances.

clinical effects, switching to nerve pulse therapy was

Since these substances are

involved in radicular blood flow regulation, theofcervicalradiculopathies

was

the

first

considered to be appropriate.

accumulation of SP and CGRP and similar substances
due to decreased axoplasmic flow causes inflammation

V. Conclusions

and thus conceivably promotes the development of1) Comparison of muscle pulse therapy and nerve

intraradicularpulse

edema.

Also,

Takahashi

etal.14)

therapyforthetreatmentofcervicalobserved the blood flow in the lumbar spinal cord andradiculopathies showed in both groups a significant

nerve roots with a temperature gradient tissue blood

improvement between the first visit and after 3

flow meter following stimulation of the sciatic nerve

months of treatment, the improvement being ofusing 20 Hz, 20 V, 0.5msec pulses in animal (dogs)

approximately the same degree in both groups.

experiments. The results revealed a reactive increase2) The nerve pulse therapy transition group refers toin blood flow in this region. Also, based on the results

those patients in whom, in spite of one month ofof these experiments, this research attempted to apply

continuous treatment with the muscle pulse therapy,transdermal electrostimulation of peripheral nerves

no effects were obtained. One month after treatment

for ischemia of the cauda equina and nerve roots asbegan there was a significant difference between theone of the symptomatic manifestations and found thisgroups, but after 3 months approximately the same

treatment to be effective in 56 out of 67 (83%) patientsdegree of improvement had been achieved in bothwith radicular pain15).

groups.

Consideration of the modes of action of the nerve3) This suggests, that in patients in whom treatment

pulse therapy, based on the hypotheses of Hirabayashi

with muscle pulse therapy had been ineffective,

et al. and Kobayashi as well as the experimental

improvements of the symptoms can be achieved byresults from Takahashi et al., allows to assume, thatapplication of nerve pulse therapy.

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The Journal of Kampo, Acupuncture and Integrative Medicine (KAIM)

Volume 2, Number 1 | Spring 2007

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