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Single or Multiple Electroacupuncture Sessions in Nonspecific Low Back Pain: Are We Low-Responders to Electroacupuncture?
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J Acupunct Meridian Stud 2018;--(-):--e--
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Research Article
Single or Multiple Electroacupuncture Sessions in Nonspecific Low Back Pain: Are We Low-Responders to Electroacupuncture? Ravena C. de Carvalho 1, Julia R. Parisi 1, Wiliam A. Prado 2, Joa ˜o E. de Arau ´jo 3, Andreia M. Silva 1, Josie R.T. Silva 1,*, Marcelo L. Silva 1 1
Department of Physiotherapy, College of Nursing, Federal University of Alfenas, Alfenas, MG, Brazil 2 Department of Pharmacology, School of Medicine, University of Sa˜o Paulo, Ribeira˜o Preto, SP, Brazil 3 Laboratory of Neuropsychobiology and Motor Behavior, Department of Biomechanics, Medicine, and Rehabilitation of the Locomotor System, School of Medicine, University of Sa˜o Paulo, Ribeira˜o Preto, SP, Brazil Available online - - -
Received: Oct 24, 2017 Revised: Feb 6, 2018 Accepted: Feb 7, 2018 KEYWORDS disability; electroacupuncture; low back pain; pain threshold
Abstract The objective of this study was to compare the effects of one or multiple sessions of electroacupuncture (EA) in patients with chronic low back pain. The outcome measures were visual analog score (VAS), pressure pain threshold (PPT), McGill pain questionnaire (MPQ), Roland Morris disability questionnaire (RMDQ), low back skin temperature, surface electromyography of longissimus muscle (contraction/rest) and blood cytokines. After examination (AV0), patients were submitted to EA (2 Hz, 30 minutes, bilaterally at the SP6, BL23, BL31, BL32, BL33, and BL60) and were revaluated after one week (AV1). Patients with VAS <3 (VAS <3 group, n Z 20) were directed to return after three weeks (AV2). Patients with VAS >3 (VAS >3 group, n Z 20) were submitted to one weekly EA-treatment and revaluated after three weeks (AV2). The VAS <3 group showed a significant reduction in VAS and MPQ and increased PPT in AV1, but not in AV2. No significant differences were found in RMDQ. The VAS >3 group showed reduction in VAS and increased PPT in AV1 and a reduction in MPQ and RMDQ only in AV2. No significant differences were found in
* Corresponding author. Department of Physiotherapy, College of Nursing of the Federal University of Alfenas-UNIFAL, Avenida Jovino Fernandes Sales 2600, CEP 37130-000, Alfenas, MG, Brazil. E-mail: [email protected] (J.R.T. Silva). pISSN 2005-2901 eISSN 2093-8152 https://doi.org/10.1016/j.jams.2018.02.002 ª 2018 Medical Association of Pharmacopuncture Institute, Publishing services by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Please cite this article in press as: de Carvalho RC, et al., Single or Multiple Electroacupuncture Sessions in Nonspecific Low Back Pain: Are We Low-Responders to Electroacupuncture?, Journal of Acupuncture and Meridian Studies (2018), https://doi.org/10.1016/ j.jams.2018.02.002
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R.C. de Carvalho et al. electromyography, temperature or cytokines. Thus, despite 2Hz-EA is effective reducing low back pain, some patients only experienced reduced pain intensity and improved functional capacity after full treatment.
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 irradiation [1]. Approximately one in four 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 at the age of 30 years, 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]. There has been an increasing interest in acupuncture among the public as well as health professionals. It is one of the most complementary and alternative medicine modalities widely used to treat 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, there is a significant disparity in the acupuncture techniques, and there is no standardization of treatment [5]. National Institute for Clinical Excellence guidelines on LBP and sciatica highlighted the need for promotion of selfmanagement and recommended a structured exercise program, a manual therapy, or an acupuncture treatment for 10 sessions over 12 weeks [6]. On the other hand, a report proposed not to use acupuncture for managing LBP with or without sciatica based on low-quality evidence [7]. Ushinohama et al [8] recently tested the hypothesis that a single session of ear acupuncture would be enough to reduce pain and improve balance in individuals with LBP temporarily. While a single session of ear acupuncture was effective to reduce pain intensity momentarily, it did not improve body balance. In the present study, we tested the hypothesis that a single session of electroacupuncture (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. Study This study was a quasi-experimental study approved by the Research Ethics Committee of the Federal University of Alfenas (protocol study 525.967) and financed by the National Council for Scientific and Technological Development (CNPq). All participants were properly informed regarding
the objectives and procedures and signed a statement of informed consent before testing.
2.2. Patients 2.2.1. Inclusion criteria Patients were eligible for inclusion if they were aged 30e65 years, with nonspecific chronic LBP for more than 3 months of duration and have a minimum pain intensity score of six in the visual analog score (VAS). 2.2.2. Exclusion criteria Patients were excluded if they previously underwent surgery in the spinal column, had known or suspected serious spinal pathology, fractures, tumors, inflammatory or rheumatologic disorders of the spine, severe cardiopulmonary disease, rheumatic disease, were pregnant, had a pacemaker or metal implants, previous acupuncture treatment, or did not understand the written consent form. All participants were invited to sign the participant consent form.
2.3. Procedures The methodology of this study was based on standards established by the Standards for Reporting Interventions in Clinical Trials of Acupuncture. 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 after examination (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). The patients were divided into two groups (Fig. 1), patients with less than three points in VAS (VAS <3 group, n Z 20) were directed to return after 3 weeks (AV2). If the VAS score was more than three points, patients (VAS >3 group, n Z 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 [9]. The asepsis on the application sites was provided by 70% alcohol, and the skin was shaved when necessary. The EA was carried out with stainless-steel acupuncture needle, 0.25 30 mm (Dong Bang, China) gently inserted to depths of 0.8 to 1.5 cm coupled in the electrical stimulation device (EL 608, NKL, Brusque, Brazil) with 2 Hz for 30 minutes bilaterally at the points: SP6 (Sanyinjiao), BL23 (Shenshu), BL31 (Shangliao), BL32 (Ciliao), BL33 (Zhongliao), and BL60 (Kunlun). An experienced therapist performed the needle insertion with
Please cite this article in press as: de Carvalho RC, et al., Single or Multiple Electroacupuncture Sessions in Nonspecific Low Back Pain: Are We Low-Responders to Electroacupuncture?, Journal of Acupuncture and Meridian Studies (2018), https://doi.org/10.1016/ j.jams.2018.02.002
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Figure 1 Flow diagram of the VAS < 3 and VAS > 3 groups. The diagram also includes the number of volunteers who were included and excluded from the trial. AV0 Z first evaluation; AV1 Z evaluation one week after EA; AV2 Z evaluation after three weeks; EA Z electroacupuncture; VAS Z visual analog score.
the patient lying in the prone position. This therapist had 14 years of experience using EA as treatment for LBP.
2.4. Primary outcomes 2.4.1. Pain intensity Pain intensity was assessed using the VAS. The VAS is an 11-point scale ranging from 0 to 10 in which 0 indicates an absence of pain and 10 indicates unbearable pain. Participants were asked to rate their average pain levels for the week before to assessment. For all outcomes, the assessor was blinded to the participants’ group allocation. 2.4.2. Pain threshold Pressure pain threshold (PPT) was assessed by a pressure algometer (EMG 830C, EMG System, Sa ˜o Jose ´ dos Campos, Brazil) applied to the skin. PPT was measured at the following three points bilaterally: 2 cm lateral to the L1, 3, and 5 spinous process. The participants were instructed, say “yes” when they start feeling pain or discomfort. When they say “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 standard error of the mean. 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 the quantity and quality of pain which are grouped into four major domains (sensory, affective, evaluative, and miscellanea) and 20 subdomains to which intensity values are assigned scores on a scale of 1 to 5. The questionnaire is used to describe pain
experience, and the score corresponds to the sum of the aggregated values. Maximum scores will be as follows: sensorial Z 41, affective Z 14, evaluative Z 5, miscellanea Z 17, and total Z 77. 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 and Teixeiro [10]. 2.4.4. Disability The Roland Morris disability questionnaire (RMDQ) was used to assess functional disability due to LBP. This questionnaire consists of 24 questions that focus on the regular activities of daily life. Each affirmative answer corresponds to one point, and the final score is determined by the total number of points; the total score ranges from 0 to 24, and higher scores reflect increased disability. Scores above 14 indicate severe impairment. The questionnaire was translated and validated by Monteiro et al [11].
2.5. Secondary outcomes 2.5.1. Skin temperature Infrared thermographic camera, ThermaCAM (FLIR System, Wilsonville, OR, USA), was used for the measurement of low back skin temperature. The distance between the object (low back) and infrared camera was 1 m, and it was constant during the experiment. Low back in orthostatic position was photographed after 15-minute airconditioning (23 C). Furthermore, the following instructions were determined: (1) do not wear restrictive clothing, such as a bra, to the exam; (2) tie the hair up; (3) no prolonged sun exposure (especially sunburn) to the
Please cite this article in press as: de Carvalho RC, et al., Single or Multiple Electroacupuncture Sessions in Nonspecific Low Back Pain: Are We Low-Responders to Electroacupuncture?, Journal of Acupuncture and Meridian Studies (2018), https://doi.org/10.1016/ j.jams.2018.02.002
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breasts 5 days prior to your exam; (4) no use of lotions, creams, powders, or makeup on the breasts on the day of the exam; (5) no use of deodorants or antiperspirants on the day of your exam; (6) no exercise 4 hours prior to the exam; (7) To avoid skin abrasions, no shaving, waxing, etc. on the day of the exam; (8) if bathing, it must be no closer than 1 hour before the exam; (9) do not drink any hot beverages for 1e2 hours prior the exam; and (10) No smoking at least 1 hour before imaging. Software FLIR Tools Software for Mac and PC (FLIR System) processed the data.
distributions, an analysis of variance for repeated measures and Tukey’s test were applied. For data that were not normally distributed, a KruskaleWallis test and Dunn’s test were utilized. The Student t test for independent samples was used to determine differences of the characteristics of the participants between groups. Fisher’s exact test was used to compare female gender differences between groups. The data were processed using SPSS 20.0 software (IBM, Armonk, New York, USA) and significance was set at a level of 5% (p < 0.05).
2.5.2. Electromyography analysis Electromyography (EMG) recordings were made using Trigno Wireless Systems (Delsys, Natick, USA) coupled to Systems (Delsys, Natick, USA). Before placing electrodes, we performed trichotomy and skin cleaning by friction with 70% alcohol (Farmax, Divino ´polis, Brazil) to reduce the impedance for better signal acquisition followed by the placement of the electrodes as described in the Surface Electromyography for the Non-Invasive Assessment of Muscles project [12]. For evaluation of the low back muscles, the patients lay in a prone position on an exercise bench with the low back, hips, and knees securely fixed by straps. The patients were also secured at the level of the scapula by a leather strap, which was attached to the load cell fixed to the ground. While in this position, the patients were asked to attempt to extend the trunk; given the impossibility of performing this movement, this attempt led to an isometric contraction of the low back muscles. All patients performed the protocol three times. Disposable silveresilver chloride surface electrodes (1.0 cm in diameter) were placed in a bipolar configuration bilaterally on L1, two centimeters away from this vertebra (longissimus muscle). The reference electrode was placed on the left wrist. The participants were encouraged resting (10 seconds) and maximal voluntary isometric contraction (5 seconds). The bilateral and simultaneous quantification of the signal was performed by root mean square amplitude, as recommended to evaluate the level of muscle activity [13].
3. Results
2.5.3. Blood tumor necrosis factor-a and interleukin-6 mediators Peripheral blood (5 mL) was collected in citrate vacutainers. The skin was cleaned with isopropyl alcohol and blood collection took place between 8 and 10 AM. to minimize circadian effects. The vacutainer tubes were centrifuged at 1,500 rpm for 15 min; plasma was removed in a sterile environment and stored in Eppendorf tubes at 80 C. Proinflammatory mediators tumor necrosis factor-a (TNF-a) and interleukin-6 (IL-6) were analyzed by the enzyme-linked immunosorbent assay, using DuoSet ELISA kit (R & D Systems, Minnesota, USA) for TNF-a and high sensitivity kit (QuantikineHS, R&D Systems Minneapolis, USA) for IL-6 according to the manufacturer’s instructions. Blood collection was performed in the resting state in AV0, AV1, and AV2.
2.6. Statistical analysis After tabulating the results, a ShapiroeWilk normality test was applied to all variables. For variables with normal
Ninety-six individuals were contacted and came to the testing sites. Forty-six did not meet the inclusion criteria and were excluded (Fig. 1). Thus, 50 participants were submitted to one session of EA and were revaluated after 1 week. Twenty patients showed less than three points in VAS and returned after 3 weeks. Most of them were female (82%), aged 53.23 years 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 3 weeks. Five patients did not return for sessions or left the treatment. Thus 20 patients were considered for further analysis. In this group, most of them were also female (90%) and aged 46.81 years 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 participants. No significant differences were found (p > 0.05) at first evaluation (AV0) on VAS or RMDQ in both analyzed groups. A significant reduction in VAS was observed 1 week after EA treatment in VAS<3 group (Table 2). By 3 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 3 weeks of 2Hz-EA treatment. Patients also exhibited a significant reduction in PPT after one session, and this effect was maintained after 3 weeks. MPQ and RMDQ were not reduced 1 week after EA treatment, but after 3 weeks, the patients showed a significant reduction in scores. Table 3 shows the secondary outcomes comparisons between intragroup and intergroup regarding the EMG in rest and contraction, temperature, and cytokines. No significant differences were found (p > 0.05).
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 3 weeks of treatment, they experienced reduced pain intensity and improved functional capacity. The first question to be elucidated is the initial improvement of a VAS <3 group that benefits from a single
Please cite this article in press as: de Carvalho RC, et al., Single or Multiple Electroacupuncture Sessions in Nonspecific Low Back Pain: Are We Low-Responders to Electroacupuncture?, Journal of Acupuncture and Meridian Studies (2018), https://doi.org/10.1016/ j.jams.2018.02.002
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Electroacupuncture and Low Back Pain Table 1
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Characteristics of participants.
Characteristics
Groups
Female Age (years) Body mass (kg) Body weight (m) BMI (kg/m2) VAS (AV0) Disability (RMDQ AV0)
p
VAS <3 n Z 20
VAS >3 n Z 20
17 (85%) 50.23 (46.00e54.39) 62.45 (59.11e65.78) 1.64 (1.60e1.67) 23 (21e24) 7.60 (7.14e8.05) 9.75 (7.56e11.93)
18 (90%) 46.81 (43.55e50.04) 65.05 (59.11e65.78) 1.61 (1.57e1.64) 24 (22e25) 7.45 (6.92e7.97) 10.25 (7.66e12.83)
1y 0.09* 0.15* 0.08* 0.07* 0.32* 0.38*
AV0 Z first evaluation; BMI Z body mass index; CI Z confidence interval; RMDQ Z Rolling Morris disability questionnaire; VAS Z visual analog score. Except for gender, data are presented as mean (95% CI). * Student t test for independent samples. y Fisher’s exact test.
Table 2
Primary outcomes.
Groups
Time
VAS <3, n Z 20 VAS > 3, n Z 20
AV0 AV1 AV2 AV0 AV1 AV2
VAS
7.60 (7.14e8.05) 1.80* (1.29e2.30) 7.3 (6.76e7.83) 7.45 (6.92e7.97) 6.55# (5.93e7.16) 4.51*# (3.64e5.35)
PPT Left
Right
5.68 (4.40e6.96) 13.67* (12.08e15.25) 5.48 (4.16e6.81) 5.29 (4.03e6.65) 8.33*# (7.00e9.67) 13.38*# (11.73e15.03)
6.04 (4.98e7.10) 14.38* (12.73e16.03) 5.21 (4.04e6.37) 5.57 (4.40e6.74) 8.63*# (7.28e9.97) 12.14*# (10.52e13.77)
MPQ
RMDQ
14.31 (15.85e12.74) 10.00* (11.00e8.99) 12.40 (13.81e10.98) 14.65 (16.53e12.76) 13.60 (16.01e11.18) 8.55*# (10.20e6.89)
9.75 (7.56e11.93) 8.65 (6.31e11.18) 11.40 (9.07e13.72) 11.00 (8.60e13.39) 8.75 (6.31e11.18) 5.80*# (3.58e8.01)
AV0 Z first evaluation; AV1 Z evaluation one week after EA; AV2 Z evaluation after three weeks; CI Z confidence interval; EA Z electroacupuncture; MPQ Z McGill Pain Questionnaire; PPT Z pressure pain threshold; RMDQ Z Rolling Morris disability questionnaire; VAS Z visual analog score. Data are presented as mean (95% CI). *Significantly different from instant preintragroup (p < 0,05); #Significantly different from same instant intergroup (p < 0,05).
session of EA. As a result, the patients presented a reduced VAS, PPT, and MPQ after one session of 2Hz-EA. The reason why this could occur might be because EA blocks pain sensory afferents [14,15]. This block could immediately inhibit a sensory feedback that increases the pain perceived by the patient continually, known as reverberation [16,17]. 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, and PPT, this improvement was observed because an 2 Hz-EA session was sufficient to promote effective relief (VAS < 3) in patients with chronic LBP [18]. In contrast, the disability evaluated on RMDQ after 1 week in patients submitted to one intervention with 2 HzEA was not significantly reduced despite pain reduction. It is known that LBP negatively influences disability, and this effect is more evident in more complex tasks [19]. Perhaps the reduction in pain intensity was not enough to cause changes in functional loss resulting from LBP. 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 and
can be classified as low-responders [20]. The analgesic effect of acupuncture is characterized by individual differences [21] that were reported in human beings [22] and rodents [23]. The oldest Chinese archives of acupuncture textbooks described that one in seven patients would respond poorly to acupuncture treatment [24]. Three-fifth of the rats were low-responders or nonresponders [25]. Recent data from animal experiments offered a biochemical basis for these poor nonresponders to EA, and the higher expression of cholecystokinin octapeptide (CCK-8) receptors might be involved [26,27]. CCK-8 is a potent endogenous neuropeptide acting on the CCKA/CCKB with antiopioid activity [26]. However, no clinical study was found comparing endogenous CCK levels or CCK receptor phenotyping among poor or nonresponders to acupuncture. Meanwhile, 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 and Cheng [28] found that patients with lower levels of pain in VAS after intervention also had increased lumbar spine functionality by RMDQ, which occurred in our study after 4 weeks.
Please cite this article in press as: de Carvalho RC, et al., Single or Multiple Electroacupuncture Sessions in Nonspecific Low Back Pain: Are We Low-Responders to Electroacupuncture?, Journal of Acupuncture and Meridian Studies (2018), https://doi.org/10.1016/ j.jams.2018.02.002
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AV0 AV1 AV2 AV0 AV1 AV2 VAS < 3, n Z 20
VAS > 3, n Z 20
57.74 81.71 53.18 52.40 50.10 82.23
AV0 Z first evaluation; AV1 Z evaluation one week after EA; AV2 Z evaluation after three weeks; CI Z confidence interval; EMG Z electromyography; RMS Z root mean square; IL6 Z interleukin 6; TNF-a Z tumor necrosis factor-alpha; VAS Z visual analog score. Data are presented as mean (95% CI).
(14.90e16.48) (15.15e16.56) (15.45e17.26) (14.35e15.54) (14.78e16.40) (13.86e15.63) 98.40 (81.38e115.42) 98.07 (80.46e115.67) 83.57 (68.53e98.60) 97.78 (78.11e117.44) 102.30 (84.35e120.25) 98.25 (82.16e114.33) (46.98e92.53) (59.62e108.37) (41.31e89.35) (51.47e100.42) (59.00e106.17) (69.55e109.86)
Time Groups
Left
Secondary outcomes. Table 3
(24.32e91.31) (58.73e104.68) (32.82e73.54) (31.82e72.99) (28.81e71.39) (58.47e105.98)
69.76 84.00 65.33 75.95 82.59 89.71
EMG (RMS) Rest
Right
92.76 95.14 84.53 74.47 87.38 87.17
(81.05e104.47) (81.90e108.38) (66.62e102.45) (56.37e92.58) (71.82e102.93) (73.83e100.51)
Right Left
EMG (RMS) Contraction
Temperature
31.8 (31.25e32.31) 31.52 (31.01e32.04) 31.06 (30.41e31.72) 31.02 (31.55e32.48) 31.84 (31.14e32.09) 31.43 (30.78e32.09)
15.69 15.86 16.36 14.94 15.59 14.75
IL-6
Cytokines
35.42 34.79 34.13 34.78 33.89 33.82
(34.71e36.13) (34.03e35.55) (33.26e34.99) (34.21e35.35) (33.16e34.62) (33.03e34.60)
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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 [29]. 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. Regarding this study, 30 minutes of 2 Hz-EA in single or multiple sessions was not enough to cause changes in the EMG activity; this may be related to the time after the intervention and also to the number of sessions, perhaps the application of more sessions could have effectiveness with this therapy. Findings from previous studies revealed a direct association between actual pain intensity and muscle activation [30,31]. The presence of pain caused by the continuous discharge of the nociceptors located in the lumbar region would reduce the activation of proprioceptors, mainly the muscle spindles, thus affecting EMG. Therefore, the decrease in the EMG activity of the muscles induces muscle relaxation and pain relief. However, our results do not confirm this hypothesis given that despite the reduction in pain intensity and an increase in RMDQ, muscle activation on rest or in isometric contraction remained unaffected after the EA treatment. A limitation of this study is that the recording of muscle EMG was conducted using surface electrodes, and 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 [32]. Thus, either 2 Hz-EA is unable to alter temperature data, 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-a was not modified by treatment with single or repeated sessions of 2 Hz-EA. Although elevated serum IL-6 levels in individuals with a history of sciatica have been demonstrated [33,34], in patients with LBP, no increase was observed in these levels [35]. This could explain our findings, since LBP may present different causes, inflammatory or not, and may present groups in which 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 and prespecification 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) would have 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 effects of acupuncture on LBP.
Please cite this article in press as: de Carvalho RC, et al., Single or Multiple Electroacupuncture Sessions in Nonspecific Low Back Pain: Are We Low-Responders to Electroacupuncture?, Journal of Acupuncture and Meridian Studies (2018), https://doi.org/10.1016/ j.jams.2018.02.002
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Electroacupuncture and Low Back Pain In conclusion, the findings showed that 2 Hz-EA is effective in temporarily reducing pain intensity, but this is not enough to improve disability or maintain the effects for a long time. However, some patients who did not have pain reduction after one session experienced reduced pain intensity and improved functional capacity after 3 weeks of treatment. This could explain why trials evaluating acupuncture for LBP have failed to find real acupuncture superior to sham or superficial control treatments and raised questions about whether we are low-responders to EA?
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[9]
[10]
[11]
[12]
Disclosure statement The authors declare that they have no conflicts of interest and no financial interests related to the material of this manuscript.
Acknowledgments The authors thank Luciana Costa Teodoro and Luiz Toma ´s da Silva for technical assistance; Dr. Giovane Galdino de Souza and Dr. Daniele Sirineu Pereira for the assistance during this project. This work was supported by CNPq (Process No. 401161/2013-7) and Julia Risso Parisi and Ravena Carolina de Carvalho were recipients of CNPq ATP-A fellowships (Process No. 373086/2014-8 and 374788/2015-4, respectively).
[13] [14] [15]
[16]
[17]
[18]
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a randomized controlled trial. Braz J Phys Ther 2016;20(4): 328e35. Lee SH, Kim CE, Lee IS, Jung WM, Kim HG, Jang H, et al. Network analysis of acupuncture points used in the treatment of low back pain. Evid Based Complement Alternat Med 2013; 2013:402180. Pimenta CA, Teixeiro MJ. Proposal to adapt the McGill pain questionnaire into Portuguese. Rev Esc Enferm USP 1996; 30(3):473e83. Monteiro J, Faisca L, Nunes O, Hipolito J. Roland Morris disability questionnaire e adaptation and validation for the Portuguese speaking patients with back pain. Acta Med Port 2010;23(5):761e6. Hermens HJ, Freriks B, Disselhorst-Klug C, Rau G. Development of recommendations for SEMG sensors and sensor placement procedures. J Electromyogr Kinesiol 2000;10(5): 361e74. De Luca C. The use of surface electromyography in biomechanics. J Appl Biomech 1997;13(2):28. Han JS. Acupuncture and endorphins. Neurosci Lett 2004; 361(1e3):258e61. Brinkhaus B, Witt CM, Jena S, Linde K, Streng A, Wagenpfeil S, et al. Acupuncture in patients with chronic low back pain: a randomized controlled trial. Arch Intern Med 2006;166(4): 450e7. Cui JG, Holmin S, Mathiesen T, Meyerson BA, Linderoth B. Possible role of inflammatory mediators in tactile hypersensitivity in rat models of mononeuropathy. Pain 2000;88(3): 239e48. Homma Y, Brull SJ, Zhang JM. A comparison of chronic pain behavior following local application of tumor necrosis factor alpha to the normal and mechanically compressed lumbar ganglia in the rat. Pain 2002;95(3):239e46. Carlsson CP, Sjolund BH. Acupuncture for chronic low back pain: a randomized placebo-controlled study with long-term follow-up. Clin J Pain 2001;17(4):296e305. Di Iorio A, Abate M, Guralnik JM, Bandinelli S, Cecchi F, Cherubini A, et al. From chronic low back pain to disability, a multifactorial mediated pathway: the InCHIANTI study. Spine (Phila Pa 1976) 2007;32(26):E809e15. Lundeberg T, Lund I. Treatment recommendations should take account of individual patient variation not just group responses. Acupunct Med 2009;27(1):31e2. Zhao ZQ. Neural mechanism underlying acupuncture analgesia. Prog Neurobiol 2008;85(4):355e75. Kong J, Fufa DT, Gerber AJ, Rosman IS, Vangel MG, Gracely RH, et al. Psychophysical outcomes from a randomized pilot study of manual, electro, and sham acupuncture treatment on experimentally induced thermal pain. J Pain 2005;6(1):55e64. Sudakov SK, Borisova EV, Lyupina YV. Influence of inheritance and fostering on sensitivity to effects of morphine on nociception and locomotor activity in two inbred rat strains. Neuropharmacology 1996;35(8):1131e4. Leung L. Neurophysiological basis of acupuncture-induced analgesiaean updated review. J Acupunct Meridian Stud 2012; 5(6):9. Silva ML, Silva JR, Prado WA. Analgesia induced by 2- or 100-Hz electroacupuncture in the rat tail-flick test depends on the anterior pretectal nucleus. Life Sci 2013;93(20):742e54. Han JS, Ding XZ, Fan SG. Cholecystokinin octapeptide (CCK-8): antagonism to electroacupuncture analgesia and a possible role in electroacupuncture tolerance. Pain 1986;27(1): 101e15. Huang C, Hu ZP, Jiang SZ, Li HT, Han JS, Wan Y. CCK(B) receptor antagonist L365,260 potentiates the efficacy to and reverses chronic tolerance to electroacupuncture-induced analgesia in mice. Brain Res Bull 2007;71(5):447e51.
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8 [28] Tsui ML, Cheing GL. The effectiveness of electroacupuncture versus electrical heat acupuncture in the management of chronic low-back pain. J Altern Complement Med 2004;10(5): 803e9. [29] Koppenhaver SL, Walker MJ, Su J, McGowen JM, Umlauf L, Harris KD, et al. Changes in lumbar multifidus muscle function and nociceptive sensitivity in low back pain patient responders versus non-responders after dry needling treatment. Man Ther 2015;20(6):769e76. [30] Ekstrom RA, Osborn RW, Hauer PL. Surface electromyographic analysis of the low back muscles during rehabilitation exercises. J Orthop Sports Phys Ther 2008;38(12):736e45. [31] Linsinski P. Surface EMG in chronic low back pain. Eur Spine J 2000;9(6):559e62.
R.C. de Carvalho et al. [32] Brenner M, Braun C, Oster M, Gulko PS. Thermal signature analysis as a novel method for evaluating inflammatory arthritis activity. Ann Rheum Dis 2006;65(3):306e11. [33] Koch A, Zacharowski K, Boehm O, Stevens M, Lipfert P, von Giesen HJ, et al. Nitric oxide and pro-inflammatory cytokines correlate with pain intensity in chronic pain patients. Inflammation Research 2007;56(1):5. [34] Geiss A, Varadi E, Steinbach K, Bauer HW, Anton F. Psychoneuroimmunological correlates of persisting sciatic pain in patients who underwent discectomy. Neurosci Lett 1997; 237(2e3):65e8. [35] Brisby H, Olmarker K, Larsson K, Nutu M, Rydevik B. Proinflammatory cytokines in cerebrospinal fluid and serum in patients with disc herniation and sciatica. Eur Spine J 2002;11(1):62e6.
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Research Article
Single or Multiple Electroacupuncture Sessions in Nonspecific Low Back Pain: Are We Low-Responders to Electroacupuncture? Ravena C. de Carvalho 1, Julia R. Parisi 1, Wiliam A. Prado 2, Joa ˜o E. de Arau ´jo 3, Andreia M. Silva 1, Josie R.T. Silva 1,*, Marcelo L. Silva 1 1
Department of Physiotherapy, College of Nursing, Federal University of Alfenas, Alfenas, MG, Brazil 2 Department of Pharmacology, School of Medicine, University of Sa˜o Paulo, Ribeira˜o Preto, SP, Brazil 3 Laboratory of Neuropsychobiology and Motor Behavior, Department of Biomechanics, Medicine, and Rehabilitation of the Locomotor System, School of Medicine, University of Sa˜o Paulo, Ribeira˜o Preto, SP, Brazil Available online - - -
Received: Oct 24, 2017 Revised: Feb 6, 2018 Accepted: Feb 7, 2018 KEYWORDS disability; electroacupuncture; low back pain; pain threshold
Abstract The objective of this study was to compare the effects of one or multiple sessions of electroacupuncture (EA) in patients with chronic low back pain. The outcome measures were visual analog score (VAS), pressure pain threshold (PPT), McGill pain questionnaire (MPQ), Roland Morris disability questionnaire (RMDQ), low back skin temperature, surface electromyography of longissimus muscle (contraction/rest) and blood cytokines. After examination (AV0), patients were submitted to EA (2 Hz, 30 minutes, bilaterally at the SP6, BL23, BL31, BL32, BL33, and BL60) and were revaluated after one week (AV1). Patients with VAS <3 (VAS <3 group, n Z 20) were directed to return after three weeks (AV2). Patients with VAS >3 (VAS >3 group, n Z 20) were submitted to one weekly EA-treatment and revaluated after three weeks (AV2). The VAS <3 group showed a significant reduction in VAS and MPQ and increased PPT in AV1, but not in AV2. No significant differences were found in RMDQ. The VAS >3 group showed reduction in VAS and increased PPT in AV1 and a reduction in MPQ and RMDQ only in AV2. No significant differences were found in
* Corresponding author. Department of Physiotherapy, College of Nursing of the Federal University of Alfenas-UNIFAL, Avenida Jovino Fernandes Sales 2600, CEP 37130-000, Alfenas, MG, Brazil. E-mail: [email protected] (J.R.T. Silva). pISSN 2005-2901 eISSN 2093-8152 https://doi.org/10.1016/j.jams.2018.02.002 ª 2018 Medical Association of Pharmacopuncture Institute, Publishing services by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Please cite this article in press as: de Carvalho RC, et al., Single or Multiple Electroacupuncture Sessions in Nonspecific Low Back Pain: Are We Low-Responders to Electroacupuncture?, Journal of Acupuncture and Meridian Studies (2018), https://doi.org/10.1016/ j.jams.2018.02.002
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R.C. de Carvalho et al. electromyography, temperature or cytokines. Thus, despite 2Hz-EA is effective reducing low back pain, some patients only experienced reduced pain intensity and improved functional capacity after full treatment.
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 irradiation [1]. Approximately one in four 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 at the age of 30 years, 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]. There has been an increasing interest in acupuncture among the public as well as health professionals. It is one of the most complementary and alternative medicine modalities widely used to treat 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, there is a significant disparity in the acupuncture techniques, and there is no standardization of treatment [5]. National Institute for Clinical Excellence guidelines on LBP and sciatica highlighted the need for promotion of selfmanagement and recommended a structured exercise program, a manual therapy, or an acupuncture treatment for 10 sessions over 12 weeks [6]. On the other hand, a report proposed not to use acupuncture for managing LBP with or without sciatica based on low-quality evidence [7]. Ushinohama et al [8] recently tested the hypothesis that a single session of ear acupuncture would be enough to reduce pain and improve balance in individuals with LBP temporarily. While a single session of ear acupuncture was effective to reduce pain intensity momentarily, it did not improve body balance. In the present study, we tested the hypothesis that a single session of electroacupuncture (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. Study This study was a quasi-experimental study approved by the Research Ethics Committee of the Federal University of Alfenas (protocol study 525.967) and financed by the National Council for Scientific and Technological Development (CNPq). All participants were properly informed regarding
the objectives and procedures and signed a statement of informed consent before testing.
2.2. Patients 2.2.1. Inclusion criteria Patients were eligible for inclusion if they were aged 30e65 years, with nonspecific chronic LBP for more than 3 months of duration and have a minimum pain intensity score of six in the visual analog score (VAS). 2.2.2. Exclusion criteria Patients were excluded if they previously underwent surgery in the spinal column, had known or suspected serious spinal pathology, fractures, tumors, inflammatory or rheumatologic disorders of the spine, severe cardiopulmonary disease, rheumatic disease, were pregnant, had a pacemaker or metal implants, previous acupuncture treatment, or did not understand the written consent form. All participants were invited to sign the participant consent form.
2.3. Procedures The methodology of this study was based on standards established by the Standards for Reporting Interventions in Clinical Trials of Acupuncture. 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 after examination (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). The patients were divided into two groups (Fig. 1), patients with less than three points in VAS (VAS <3 group, n Z 20) were directed to return after 3 weeks (AV2). If the VAS score was more than three points, patients (VAS >3 group, n Z 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 [9]. The asepsis on the application sites was provided by 70% alcohol, and the skin was shaved when necessary. The EA was carried out with stainless-steel acupuncture needle, 0.25 30 mm (Dong Bang, China) gently inserted to depths of 0.8 to 1.5 cm coupled in the electrical stimulation device (EL 608, NKL, Brusque, Brazil) with 2 Hz for 30 minutes bilaterally at the points: SP6 (Sanyinjiao), BL23 (Shenshu), BL31 (Shangliao), BL32 (Ciliao), BL33 (Zhongliao), and BL60 (Kunlun). An experienced therapist performed the needle insertion with
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Figure 1 Flow diagram of the VAS < 3 and VAS > 3 groups. The diagram also includes the number of volunteers who were included and excluded from the trial. AV0 Z first evaluation; AV1 Z evaluation one week after EA; AV2 Z evaluation after three weeks; EA Z electroacupuncture; VAS Z visual analog score.
the patient lying in the prone position. This therapist had 14 years of experience using EA as treatment for LBP.
2.4. Primary outcomes 2.4.1. Pain intensity Pain intensity was assessed using the VAS. The VAS is an 11-point scale ranging from 0 to 10 in which 0 indicates an absence of pain and 10 indicates unbearable pain. Participants were asked to rate their average pain levels for the week before to assessment. For all outcomes, the assessor was blinded to the participants’ group allocation. 2.4.2. Pain threshold Pressure pain threshold (PPT) was assessed by a pressure algometer (EMG 830C, EMG System, Sa ˜o Jose ´ dos Campos, Brazil) applied to the skin. PPT was measured at the following three points bilaterally: 2 cm lateral to the L1, 3, and 5 spinous process. The participants were instructed, say “yes” when they start feeling pain or discomfort. When they say “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 standard error of the mean. 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 the quantity and quality of pain which are grouped into four major domains (sensory, affective, evaluative, and miscellanea) and 20 subdomains to which intensity values are assigned scores on a scale of 1 to 5. The questionnaire is used to describe pain
experience, and the score corresponds to the sum of the aggregated values. Maximum scores will be as follows: sensorial Z 41, affective Z 14, evaluative Z 5, miscellanea Z 17, and total Z 77. 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 and Teixeiro [10]. 2.4.4. Disability The Roland Morris disability questionnaire (RMDQ) was used to assess functional disability due to LBP. This questionnaire consists of 24 questions that focus on the regular activities of daily life. Each affirmative answer corresponds to one point, and the final score is determined by the total number of points; the total score ranges from 0 to 24, and higher scores reflect increased disability. Scores above 14 indicate severe impairment. The questionnaire was translated and validated by Monteiro et al [11].
2.5. Secondary outcomes 2.5.1. Skin temperature Infrared thermographic camera, ThermaCAM (FLIR System, Wilsonville, OR, USA), was used for the measurement of low back skin temperature. The distance between the object (low back) and infrared camera was 1 m, and it was constant during the experiment. Low back in orthostatic position was photographed after 15-minute airconditioning (23 C). Furthermore, the following instructions were determined: (1) do not wear restrictive clothing, such as a bra, to the exam; (2) tie the hair up; (3) no prolonged sun exposure (especially sunburn) to the
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breasts 5 days prior to your exam; (4) no use of lotions, creams, powders, or makeup on the breasts on the day of the exam; (5) no use of deodorants or antiperspirants on the day of your exam; (6) no exercise 4 hours prior to the exam; (7) To avoid skin abrasions, no shaving, waxing, etc. on the day of the exam; (8) if bathing, it must be no closer than 1 hour before the exam; (9) do not drink any hot beverages for 1e2 hours prior the exam; and (10) No smoking at least 1 hour before imaging. Software FLIR Tools Software for Mac and PC (FLIR System) processed the data.
distributions, an analysis of variance for repeated measures and Tukey’s test were applied. For data that were not normally distributed, a KruskaleWallis test and Dunn’s test were utilized. The Student t test for independent samples was used to determine differences of the characteristics of the participants between groups. Fisher’s exact test was used to compare female gender differences between groups. The data were processed using SPSS 20.0 software (IBM, Armonk, New York, USA) and significance was set at a level of 5% (p < 0.05).
2.5.2. Electromyography analysis Electromyography (EMG) recordings were made using Trigno Wireless Systems (Delsys, Natick, USA) coupled to Systems (Delsys, Natick, USA). Before placing electrodes, we performed trichotomy and skin cleaning by friction with 70% alcohol (Farmax, Divino ´polis, Brazil) to reduce the impedance for better signal acquisition followed by the placement of the electrodes as described in the Surface Electromyography for the Non-Invasive Assessment of Muscles project [12]. For evaluation of the low back muscles, the patients lay in a prone position on an exercise bench with the low back, hips, and knees securely fixed by straps. The patients were also secured at the level of the scapula by a leather strap, which was attached to the load cell fixed to the ground. While in this position, the patients were asked to attempt to extend the trunk; given the impossibility of performing this movement, this attempt led to an isometric contraction of the low back muscles. All patients performed the protocol three times. Disposable silveresilver chloride surface electrodes (1.0 cm in diameter) were placed in a bipolar configuration bilaterally on L1, two centimeters away from this vertebra (longissimus muscle). The reference electrode was placed on the left wrist. The participants were encouraged resting (10 seconds) and maximal voluntary isometric contraction (5 seconds). The bilateral and simultaneous quantification of the signal was performed by root mean square amplitude, as recommended to evaluate the level of muscle activity [13].
3. Results
2.5.3. Blood tumor necrosis factor-a and interleukin-6 mediators Peripheral blood (5 mL) was collected in citrate vacutainers. The skin was cleaned with isopropyl alcohol and blood collection took place between 8 and 10 AM. to minimize circadian effects. The vacutainer tubes were centrifuged at 1,500 rpm for 15 min; plasma was removed in a sterile environment and stored in Eppendorf tubes at 80 C. Proinflammatory mediators tumor necrosis factor-a (TNF-a) and interleukin-6 (IL-6) were analyzed by the enzyme-linked immunosorbent assay, using DuoSet ELISA kit (R & D Systems, Minnesota, USA) for TNF-a and high sensitivity kit (QuantikineHS, R&D Systems Minneapolis, USA) for IL-6 according to the manufacturer’s instructions. Blood collection was performed in the resting state in AV0, AV1, and AV2.
2.6. Statistical analysis After tabulating the results, a ShapiroeWilk normality test was applied to all variables. For variables with normal
Ninety-six individuals were contacted and came to the testing sites. Forty-six did not meet the inclusion criteria and were excluded (Fig. 1). Thus, 50 participants were submitted to one session of EA and were revaluated after 1 week. Twenty patients showed less than three points in VAS and returned after 3 weeks. Most of them were female (82%), aged 53.23 years 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 3 weeks. Five patients did not return for sessions or left the treatment. Thus 20 patients were considered for further analysis. In this group, most of them were also female (90%) and aged 46.81 years 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 participants. No significant differences were found (p > 0.05) at first evaluation (AV0) on VAS or RMDQ in both analyzed groups. A significant reduction in VAS was observed 1 week after EA treatment in VAS<3 group (Table 2). By 3 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 3 weeks of 2Hz-EA treatment. Patients also exhibited a significant reduction in PPT after one session, and this effect was maintained after 3 weeks. MPQ and RMDQ were not reduced 1 week after EA treatment, but after 3 weeks, the patients showed a significant reduction in scores. Table 3 shows the secondary outcomes comparisons between intragroup and intergroup regarding the EMG in rest and contraction, temperature, and cytokines. No significant differences were found (p > 0.05).
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 3 weeks of treatment, they experienced reduced pain intensity and improved functional capacity. The first question to be elucidated is the initial improvement of a VAS <3 group that benefits from a single
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Electroacupuncture and Low Back Pain Table 1
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Characteristics of participants.
Characteristics
Groups
Female Age (years) Body mass (kg) Body weight (m) BMI (kg/m2) VAS (AV0) Disability (RMDQ AV0)
p
VAS <3 n Z 20
VAS >3 n Z 20
17 (85%) 50.23 (46.00e54.39) 62.45 (59.11e65.78) 1.64 (1.60e1.67) 23 (21e24) 7.60 (7.14e8.05) 9.75 (7.56e11.93)
18 (90%) 46.81 (43.55e50.04) 65.05 (59.11e65.78) 1.61 (1.57e1.64) 24 (22e25) 7.45 (6.92e7.97) 10.25 (7.66e12.83)
1y 0.09* 0.15* 0.08* 0.07* 0.32* 0.38*
AV0 Z first evaluation; BMI Z body mass index; CI Z confidence interval; RMDQ Z Rolling Morris disability questionnaire; VAS Z visual analog score. Except for gender, data are presented as mean (95% CI). * Student t test for independent samples. y Fisher’s exact test.
Table 2
Primary outcomes.
Groups
Time
VAS <3, n Z 20 VAS > 3, n Z 20
AV0 AV1 AV2 AV0 AV1 AV2
VAS
7.60 (7.14e8.05) 1.80* (1.29e2.30) 7.3 (6.76e7.83) 7.45 (6.92e7.97) 6.55# (5.93e7.16) 4.51*# (3.64e5.35)
PPT Left
Right
5.68 (4.40e6.96) 13.67* (12.08e15.25) 5.48 (4.16e6.81) 5.29 (4.03e6.65) 8.33*# (7.00e9.67) 13.38*# (11.73e15.03)
6.04 (4.98e7.10) 14.38* (12.73e16.03) 5.21 (4.04e6.37) 5.57 (4.40e6.74) 8.63*# (7.28e9.97) 12.14*# (10.52e13.77)
MPQ
RMDQ
14.31 (15.85e12.74) 10.00* (11.00e8.99) 12.40 (13.81e10.98) 14.65 (16.53e12.76) 13.60 (16.01e11.18) 8.55*# (10.20e6.89)
9.75 (7.56e11.93) 8.65 (6.31e11.18) 11.40 (9.07e13.72) 11.00 (8.60e13.39) 8.75 (6.31e11.18) 5.80*# (3.58e8.01)
AV0 Z first evaluation; AV1 Z evaluation one week after EA; AV2 Z evaluation after three weeks; CI Z confidence interval; EA Z electroacupuncture; MPQ Z McGill Pain Questionnaire; PPT Z pressure pain threshold; RMDQ Z Rolling Morris disability questionnaire; VAS Z visual analog score. Data are presented as mean (95% CI). *Significantly different from instant preintragroup (p < 0,05); #Significantly different from same instant intergroup (p < 0,05).
session of EA. As a result, the patients presented a reduced VAS, PPT, and MPQ after one session of 2Hz-EA. The reason why this could occur might be because EA blocks pain sensory afferents [14,15]. This block could immediately inhibit a sensory feedback that increases the pain perceived by the patient continually, known as reverberation [16,17]. 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, and PPT, this improvement was observed because an 2 Hz-EA session was sufficient to promote effective relief (VAS < 3) in patients with chronic LBP [18]. In contrast, the disability evaluated on RMDQ after 1 week in patients submitted to one intervention with 2 HzEA was not significantly reduced despite pain reduction. It is known that LBP negatively influences disability, and this effect is more evident in more complex tasks [19]. Perhaps the reduction in pain intensity was not enough to cause changes in functional loss resulting from LBP. 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 and
can be classified as low-responders [20]. The analgesic effect of acupuncture is characterized by individual differences [21] that were reported in human beings [22] and rodents [23]. The oldest Chinese archives of acupuncture textbooks described that one in seven patients would respond poorly to acupuncture treatment [24]. Three-fifth of the rats were low-responders or nonresponders [25]. Recent data from animal experiments offered a biochemical basis for these poor nonresponders to EA, and the higher expression of cholecystokinin octapeptide (CCK-8) receptors might be involved [26,27]. CCK-8 is a potent endogenous neuropeptide acting on the CCKA/CCKB with antiopioid activity [26]. However, no clinical study was found comparing endogenous CCK levels or CCK receptor phenotyping among poor or nonresponders to acupuncture. Meanwhile, 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 and Cheng [28] found that patients with lower levels of pain in VAS after intervention also had increased lumbar spine functionality by RMDQ, which occurred in our study after 4 weeks.
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AV0 AV1 AV2 AV0 AV1 AV2 VAS < 3, n Z 20
VAS > 3, n Z 20
57.74 81.71 53.18 52.40 50.10 82.23
AV0 Z first evaluation; AV1 Z evaluation one week after EA; AV2 Z evaluation after three weeks; CI Z confidence interval; EMG Z electromyography; RMS Z root mean square; IL6 Z interleukin 6; TNF-a Z tumor necrosis factor-alpha; VAS Z visual analog score. Data are presented as mean (95% CI).
(14.90e16.48) (15.15e16.56) (15.45e17.26) (14.35e15.54) (14.78e16.40) (13.86e15.63) 98.40 (81.38e115.42) 98.07 (80.46e115.67) 83.57 (68.53e98.60) 97.78 (78.11e117.44) 102.30 (84.35e120.25) 98.25 (82.16e114.33) (46.98e92.53) (59.62e108.37) (41.31e89.35) (51.47e100.42) (59.00e106.17) (69.55e109.86)
Time Groups
Left
Secondary outcomes. Table 3
(24.32e91.31) (58.73e104.68) (32.82e73.54) (31.82e72.99) (28.81e71.39) (58.47e105.98)
69.76 84.00 65.33 75.95 82.59 89.71
EMG (RMS) Rest
Right
92.76 95.14 84.53 74.47 87.38 87.17
(81.05e104.47) (81.90e108.38) (66.62e102.45) (56.37e92.58) (71.82e102.93) (73.83e100.51)
Right Left
EMG (RMS) Contraction
Temperature
31.8 (31.25e32.31) 31.52 (31.01e32.04) 31.06 (30.41e31.72) 31.02 (31.55e32.48) 31.84 (31.14e32.09) 31.43 (30.78e32.09)
15.69 15.86 16.36 14.94 15.59 14.75
IL-6
Cytokines
35.42 34.79 34.13 34.78 33.89 33.82
(34.71e36.13) (34.03e35.55) (33.26e34.99) (34.21e35.35) (33.16e34.62) (33.03e34.60)
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TNF-a
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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 [29]. 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. Regarding this study, 30 minutes of 2 Hz-EA in single or multiple sessions was not enough to cause changes in the EMG activity; this may be related to the time after the intervention and also to the number of sessions, perhaps the application of more sessions could have effectiveness with this therapy. Findings from previous studies revealed a direct association between actual pain intensity and muscle activation [30,31]. The presence of pain caused by the continuous discharge of the nociceptors located in the lumbar region would reduce the activation of proprioceptors, mainly the muscle spindles, thus affecting EMG. Therefore, the decrease in the EMG activity of the muscles induces muscle relaxation and pain relief. However, our results do not confirm this hypothesis given that despite the reduction in pain intensity and an increase in RMDQ, muscle activation on rest or in isometric contraction remained unaffected after the EA treatment. A limitation of this study is that the recording of muscle EMG was conducted using surface electrodes, and 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 [32]. Thus, either 2 Hz-EA is unable to alter temperature data, 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-a was not modified by treatment with single or repeated sessions of 2 Hz-EA. Although elevated serum IL-6 levels in individuals with a history of sciatica have been demonstrated [33,34], in patients with LBP, no increase was observed in these levels [35]. This could explain our findings, since LBP may present different causes, inflammatory or not, and may present groups in which 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 and prespecification 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) would have 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 effects of acupuncture on LBP.
Please cite this article in press as: de Carvalho RC, et al., Single or Multiple Electroacupuncture Sessions in Nonspecific Low Back Pain: Are We Low-Responders to Electroacupuncture?, Journal of Acupuncture and Meridian Studies (2018), https://doi.org/10.1016/ j.jams.2018.02.002
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Electroacupuncture and Low Back Pain In conclusion, the findings showed that 2 Hz-EA is effective in temporarily reducing pain intensity, but this is not enough to improve disability or maintain the effects for a long time. However, some patients who did not have pain reduction after one session experienced reduced pain intensity and improved functional capacity after 3 weeks of treatment. This could explain why trials evaluating acupuncture for LBP have failed to find real acupuncture superior to sham or superficial control treatments and raised questions about whether we are low-responders to EA?
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Disclosure statement The authors declare that they have no conflicts of interest and no financial interests related to the material of this manuscript.
Acknowledgments The authors thank Luciana Costa Teodoro and Luiz Toma ´s da Silva for technical assistance; Dr. Giovane Galdino de Souza and Dr. Daniele Sirineu Pereira for the assistance during this project. This work was supported by CNPq (Process No. 401161/2013-7) and Julia Risso Parisi and Ravena Carolina de Carvalho were recipients of CNPq ATP-A fellowships (Process No. 373086/2014-8 and 374788/2015-4, respectively).
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Please cite this article in press as: de Carvalho RC, et al., Single or Multiple Electroacupuncture Sessions in Nonspecific Low Back Pain: Are We Low-Responders to Electroacupuncture?, Journal of Acupuncture and Meridian Studies (2018), https://doi.org/10.1016/ j.jams.2018.02.002