ay in hAbstract
Electroacupuncture (EA) is reported to effectively relieve low back pain (LBP). This
study compares the effects of one or multiple sessions of EA in patients with chronic
LBP. After examination (AV0), patients were submitted to one session of EA and
revaluated after one week (AV1). Patients (<3 Group, n=20) with less than three
points were directed to return after three weeks (AV2). Patients (>3 Group, n=20)
were submitted to one weekly 2Hz-EA treatment session and revaluated after three
weeks (AV2). A significant reduction in VAS and McGill pain questionnaire (MPQ)
and an increase in Pressure pain threshold (PPT) were observed in AV1 in VAS<3
Group. After three weeks, this effect was no longer seen. No significant differences
were found Roland Morris disability questionnaire (RMDQ). The VAS>3 Group
showed a smaller but significant reduction in VAS and an increase in PPT in AV1.
MPQ and RMDQ showed a significant reduction only in AV2. No significant
differences were found in electromyography, temperature and cytokines. Thus, 2HzEA
is effective in temporarily reducing LBP, but this is not enough to improve
disability. However, some patients did not have pain reduction initially, but
experienced reduced pain intensity and improved functional capacity after full
treatment.
Keywords: Electroacupuncture, Low Back Pain, Pain Threshold, Disability.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
1. Introduction
Low back pain (LBP) is a common musculoskeletal disorder among adults and refers
to pain and discomfort localized in the lumbosacral region, with or without leg
irradiating [1]. Approximately 1 in 4 people will need medical attention in a 6-month
period. It is estimated that around 50% of the worldwide population will experience
the first LBP approximately in the 30 years old, whereas 70% of the population will
experience LBP at one point in their adulthood [2].
Although a considerable variety of pharmacologic and nonpharmacologic therapies
are available for the treatment of LBP, the effectiveness of most of these
interventions is yet to be established [3].
Acupuncture has increasing interest from the public as well as the health
professions. It is one of the most frequently complementary and alternative medicine
modalities to treat among patients suffering from LBP [4]. However, there is no
guidance for the time of treatment, the frequency of sessions, the number of needles
needed or placement of needle insertion. Still, is the significant disparity in the
acupuncture techniques and no standardization of treatment [5].
NICE guidelines highlighted the need for promotion of self-management and
recommended a structured exercise program, a manual therapy or an acupuncture
treatment by the ten sessions over 12 weeks [6]. In the other hand, a report
proposed to do not apply acupuncture for managing LBP with or without sciatica
based on low-quality evidence [7].
Ushinohama et al. [8] have recently demonstrated that a single session of ear
acupuncture was effective to reduce pain intensity momentarily, but did not improve
body balance in individuals with LBP.
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
Electroacupuncture (EA) is the application of electrical stimulation to acupuncture
needles and has been indicated in some cases of LBP [4].
In the present study, we tested the hypothesis that a single session of EA in patients
with chronic LBP would be sufficient to temporarily reduce pain intensity and
functional disability, enhancing their muscle activation and reducing local skin
temperature and blood mediators, when compared to a long-time treatment.
2. Material and Methods
2.1 Patients
2.1.1 Inclusion criteria
All participants were invited to sign the participant consent form. The inclusion
criteria were diagnosis of nonspecific chronic LBP for more than three months, 30–
65 years old and a minimum pain intensity score of 6 on the VAS.
2.1.2 Exclusion criteria
Previously surgery in the spinal column, metal implants, tumors, serious spinal
pathology or fractures, inflammatory disorders, severe cardiopulmonary disease,
rheumatic disease, pregnant, previous acupuncture treatment or did not understand
the written consent form were excluded. The methodology of this study was based
on standards established by the Standards for Reporting Interventions in Clinical
Trials of Acupuncture (SCRICTA).
2.2 Procedures
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
This study was approved by the Ethics Committee of the Federal University of
Alfenas (protocol study 525.967), and financed by the National Council for Scientific
and Technological Development (CNPq). The recruitment began on November 25,
2013, and the completion date was August 31, 2015. To examine the longevity of the
EA intervention effects, measurements were taken before treatment (AV0), after 1
week of EA treatment (AV1) and 3 weeks after the intervention (AV2). We recruited
96 patients at the Physiotherapy Clinics in Federal University of Alfenas, Minas
Gerais, Brazil. After examination (AV0), fifty patients were submitted to one session
of EA and were revaluated after one week (AV1). Patients (VAS<3 Group, n=20)
with less than three points in VAS were directed to return after three weeks (AV2). If
the VAS score was more than three points, patients (VAS>3 Group, n=20) were
submitted to one weekly 2 Hz EA treatment session lasting 30 minutes and
revaluated after three weeks (AV2). Acupuncture points chosen were selected based
on the characteristics of patients and the relevant literature. The EA was made with
an electrical stimulation device (EL 608, NKL, Brusque, Brazil) at 2 Hz for 30 minutes
at the points: bilateral SP6 (Sanyinjiao), BL23 (Shenshu), BL31 (Shangliao), BL32
(Ciliao), BL33 (Zhongliao) and BL60 (Kunlun). A 14 years experienced therapist
performed the needle insertion.
2.4 Primary outcomes
2.4.1 Pain intensity
Pain intensity was assessed using the visual analogue score (VAS). The VAS is an
11-point scale ranging from 0 to 10, with higher scores representing more pain. For
all outcomes, the assessor was blinded to the participants’ group allocation.
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
2.4.2 Pain threshold
Pressure pain threshold (PPT) was assessed by a Pressure Algometer (EMG 830C,
EMG System, São José dos Campos, Brazil) applied to the skin. The participants
were instructed, say ‘yes’ when you start feeling pain or discomfort. When said, ‘yes,’
the pressure was stopped, and the meter was removed from the skin. The threshold
was evaluated in triplicates, with the final result being the mean ±EPM.
2.4.3 The McGill Pain Questionnaire
The McGill Pain Questionnaire (MPQ) provides a multidimensional assessment of
pain. Participants completed the MPQ by rating 78 descriptors of pain which are
grouped into four domains (sensory, affective, evaluative and miscellanea). The
index of pain assessment is the sum of added values, and each word chosen in each
dimension is the maximum score for each category. Adapted to the Portuguese
language by Pimenta & Teixero [9].
2.4.4 Disability
The Roland Morris disability questionnaire (RMDQ) was used to assess functional
disability due to LBP. This questionnaire contains 24 questions with emphasis on the
regular activities of daily life. Each affirmative answer corresponds to 1 point, and the
final score is determined by the total number of points and higher scores reflect
increased disability. Scores above 14 indicate severe impairment. The questionnaire
was translated to Portuguese and validated by Monteiro et al. [10].
2.5 Secondary Outcomes
2.5.1 Skin Temperature
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
Infrared thermographic camera ThermaCAM® (FLIR System, Wilsonville, USA), was
used for the measurement of low back skin temperature. The distance between the
object (low back) and IR camera was 1 m, and it was constant during the
experiment. Low back in orthostatic position was photographed after fifteen-minute
air-conditioning (23º C). Software FLIR Tools Software for Mac and PC | FLIR
Systems processed data.
2.5.2 EMG analysis
EMG recordings were made using Trigno Wireless Systems (Delsys, Natick, USA)
coupled to Systems (Delsys, Natick, USA). Before electrodes placing we performed
trichotomy and skin cleaning by friction with 70% alcohol (Farmax, Divinópolis,
Brazil). The participants were encouraged resting (10 seconds) and maximal
voluntary isometric contraction (MVIC – 5 seconds). Three measures with electrodes
positioned bilaterally on L1, two centimeters away from this vertebra (longissimus
muscle). Quantification of the signal was performed by Root Mean Square (RMS)
amplitude, as recommended to evaluate the level of muscle activity [11].
2.5.3 Blood TNF-α and IL-6 mediators
Pro-inflammatory mediators tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6)
were analyzed through blood’s milliliters collected in citrate vacuum tubes between
8:00 am and 10:00 am. After collection, we centrifuged plasma at 1500 rpm, for 15
minutes. Subsequently, was stored at -80 °C for further analysis. Inflammatory
concentrations of mediators in plasma were analyzed by the ELISA (enzyme-linked
immunosorbent assay), using DuoSet ELISA kit (R & D Systems, Minnesota, USA)
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
for TNF-α and high sensitivity kit (QuantikineHS, R&D Systems Minneapolis, USA)
for IL-6 according to the manufacturer's instructions.
2.6 Statistical Analysis
After tabulating the results, a Shapiro-Wilk normality test was applied to all variables.
For variables with normal distributions, an analysis of variance (ANOVA) for
repeated measures and Tukey's test were applied. For data that were not normally
distributed, a Kruskal-Wallis test and Dunn's test were utilized. Fisher´s exact test
was used to compare female gender differences between groups. The data were
processed using the software SPSS 20.0 (IBM, Armonk, New York, USA) and
significance was set at a level of 5% (p<0.05).
3. Results
Ninety-six individuals were contacted and came to the testing sites. Forty-six did not
meet the inclusion criteria and were excluded (Figure 1). Thus, 50 participants were
submitted to one session of EA and were revaluated after one week. Twenty patients
showed less than three points in VAS and returned after three weeks. Most of them
were female (82%), 53.23 years old on average, and had 7.60 in VAS score on
average at AV0. Twenty-five patients showed more than three points in VAS and
were submitted to one weekly 2 Hz EA treatment and revaluated after three weeks.
Five patients did not return for sessions or leave the treatment. Thus 20 patients
were considered for further analysis. In this group, most of them were also female
(90%), 46.81 years old on average, and the pain intensity reported at the beginning
of this trial was 7.45 in VAS score. Table 1 shows the characteristics of the
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
participants. No significant differences were found (p > 0.05) at first evaluation (AV0)
on VAS or RMDQ.
A significant reduction in VAS was observed one week after EA treatment in VAS<3
Group (Table 2). By three weeks, this effect was no longer seen, and patients
returned to experience pain. The same behavior is observed on PPT on both sides
and MPQ score, but not in RMDQ. The VAS>3 Group showed a smaller but
significant reduction in VAS after one session of 2Hz EA. This decrease was
maintained after three weeks of 2Hz EA treatment. Patients also exhibited a
significant reduction in PPT after one session, and this effect was maintained after
three weeks. MPQ and RMDQ were not reduced one week after EA treatment, but
after three weeks the patients showed a significant reduction in scores.
Table 3 shows the secondary outcomes comparisons Intra- and intergroup regarding
the EMG in rest and contraction, temperature and cytokines. No significant
differences were found (p > 0.05).
ere… 4. Discussion
We tested the hypothesis that a single session of EA would be enough to reduce
pain and improve disability in individuals with LBP temporarily. The results partially
confirmed the hypothesis. While a single session of EA was effective to reduce pain
intensity momentarily, one session of EA did not improve disability. Furthermore,
some patients did not have pain reduction after one session of EA, but after three
weeks of treatment experienced reduced pain intensity and improved functional
capacity.
The first question to be elucidated is the initial improvement of a group (VAS < 3)
that benefits from a single session of EA. The reason why this could occur may be
suggested because EA blocks pain sensory afferents [12, 13]. This block could
immediately inhibit a sensory feedback that increases the pain perceived by the
patient continually, known as reverberation [14, 15]. When applied for a simple 30-
minute session the EA could impede this feedback loop and induce immediate pain
relief. According to data from VAS, MPQ, RMPQ, and PPT, this improvement was
observed because an EA session was sufficient to promote effective relief (VAS < 3)
in patients with chronic LBP [16].
Although acupuncture appears to improve symptoms from a single session
effectively, some patients are not experiencing less pain (VAS > 3 Group). It has
been speculated that some of these patients are not experiencing less pain because
of weak or nonresponse to acupuncture [17]. The analgesic effect of acupuncture is
characterized by individual differences [18] that were reported in human beings [19]
and rodents [20], therefore that individuals can be classified as low-responders.
The oldest Chinese archives of acupuncture textbooks described that one in seven
subjects would respond poorly to acupuncture treatment [21]. Third-five of the rats
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
are low- or non-responders [22]. Recent data from animal experiments offered a
biochemical basis for these poor non-responders to EA, and the higher expression of
cholecystokinin octapeptide (CCK-8) receptors might be involved [23, 24]. CCK-8 is
a potent endogenous neuropeptide acting on the CCKA/CCKB with anti-opioid activity
[23]. However, no clinical study was found comparing endogenous CCK levels or
CCK receptor phenotyping among poor or non-responders to acupuncture.
LBP negatively influences disability and this is more evident in complex tasks [25].
The disability evaluated after one week in patients submitted to one intervention with
EA was not significantly reduced despite pain reduction. Thus, the reduction in pain
intensity was not enough to cause changes in functional loss resulting from LBP.
Patients with VAS > 3 and treated with EA weekly showed a gradual decrease in
functional disability of the lumbar spine from a score of 11.00 on the first evaluation
to a score of 8.75 on the second and a score of 5.80 significantly on the last
evaluation. Tsui & Cheng [26] found that patients with lower levels of pain in VAS
after intervention also had increased lumbar spine functionality by RMDQ, which
happened in this study after four weeks.
In addition, only patients treated with EA weekly (VAS > 3 Group) showed a
continued increase in PPT. The data reported in this study are comparable with
those already reported by other investigators [27].
Taken together, these findings may suggest that the sustained decrease in pain
leads to an increase in joint utilization and consequent improvement in the functional
parameters of the lumbar spine.
Findings from previous studies revealed an association between actual pain intensity
and muscle activation [28, 29]. The continuous discharge of the nociceptors located
in the lumbar region would reduce the activation of proprioceptors and consequently
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
affecting EMG. However, our results do not confirm this hypothesis because despite
the reduction in pain intensity and an increase in RMDQ, the muscle activation on
rest or in contraction remained unaffected after the treatment.
As the recording of muscle EMG was conducted using surface electrodes, we must
consider the possibility of crosstalk interference. The presence of crosstalk is
inherently associated with the recordings obtained by surface EMG, mainly in the
evaluation of nearby muscle groups.
There were no differences in surface temperature in both groups evaluated at any
time by the EA. A reduction of the lumbar temperature throughout the treatment time
was found in previous work [30]. Thus, either EA is unable to alter temperature data,
either when performed uniquely, or when performed repeatedly, or the changes
induced by EA are deeper and impossible of being detected by thermography.
Finally, the assessment of plasma levels of IL-6 and TNF-α were not modified by
treatment with unique or repeated sessions of EA. Although elevated serum IL-6
levels in individuals with a history of sciatica have been demonstrated [31, 32], in
patients with LBP, no increase was observed in these levels [33]. This could explain
our findings, since LBP may present different causes, inflammatory or not, and may
present groups that the serum concentrations of these mediators are increased and
groups of patients that do not present alterations in the levels. Further studies,
dividing lumbar groups of inflammatory or noninflammatory origin could elucidate
such facts.
The main limitations of this trial are restricting treatment to a single component (2 Hz
EA) of Traditional Chinese medicine acupuncture; pre-specification of the
acupuncture points and number and duration of treatments; inclusion of a simulated
acupuncture control or use a real placebo EA (i.e. sham EA); this would have
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
strengthened our findings and provided additional support for the use of EA for
temporary or prolonged pain reduction in individuals with LBP. Future research is
needed to determine acupuncture effects on LBP.
In conclusion, our findings showed that 2 Hz EA is effective in reducing pain intensity
temporarily and this is not enough to improve disability or maintain the analgesic
effects for a long time. However, some patients that did not have pain reduction after
one session, experienced reduced pain intensity and improved functional capacity
after three weeks of treatment. This could explain why trials evaluating acupuncture
for
LPB have failed to find real acupuncture superior to sham or superficial control
treatments and raised questions about whether we are low-responders to EA?