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Auricular acupuncture for chronic back pain in adults: a systematic review and metanalysis

ABSTRACT

Objective

To investigate randomized clinical trials on the action of auricular acupuncture for chronic back pain in adults, and to identify the most commonly used outcomes for assessing this condition, the protocol used for applying the intervention, and the efficacy of the therapy on pain intensity.

Method

A systematic review and a metanalysis were carried out between June 2017 and May 2018, based on the PubMed, CINAHL, PEDro, Embase, Scopus, and the Virtual Health Library databases. Reference lists of systematic reviews were also explored.

Results

427 studies were located, 15 included in the qualitative analysis, and seven in the quantitative analysis. Auricular acupuncture led to positive results in 80% of the studies. The most commonly used outcomes were pain intensity and quality, medication consumption, physical disability, and quality of life. There is a lack of protocol standardization for auricular acupuncture for chronic back pain. The metanalysis results showed that auricular acupuncture was effective in reducing pain intensity scores (p=0.038).

Conclusion

Auricular acupuncture is a promising practice for the treatment of chronic back pain in adults.

Chronic Pain; Back Pain; Acupuncture, Ear; Complementary Therapies; Review

RESUMO

Objetivo

Investigar os ensaios clínicos randomizados sobre a ação da acupuntura auricular para a dor crônica nas costas em adultos, identificar os desfechos mais utilizados para avaliar essa condição, o protocolo utilizado para aplicar a intervenção e identificar nos estudos qual o efeito da terapia sobre a intensidade da dor.

Método

Revisão sistemática e metanálise, conduzidas entre junho de 2017 e maio de 2018, nas bases de dados PubMed, CINAHL, PEDro, Embase, Scopus e na Biblioteca Virtual em Saúde. Listas de referências de revisões sistemáticas também foram exploradas.

Resultados

Foram localizados 427 estudos, 15 incluídos na análise qualitativa, e sete na análise quantitativa. A acupuntura auricular obteve resultados positivos em 80% dos estudos. Os desfechos mais utilizados foram a intensidade e a qualidade da dor, consumo de medicação, incapacidade física e qualidade de vida. Não há padronização no protocolo de acupuntura auricular para dor crônica nas costas. Os resultados da metanálise apontaram que a acupuntura auricular foi eficaz em reduzir os escores de intensidade da dor (p=0,038).

Conclusão

A acupuntura auricular é uma prática promissora para o tratamento da dor crônica nas costas em adultos.

Dor Crônica; Dor nas Costas; Acupuntura Auricular; Terapias Complementares; Revisão

RESUMEN

Objetivo

Investigar los ensayos clínicos randomizados sobre la acción de la acupuntura auricular para dolor crónico en la espalda en adultos, identificar los resultados más utilizados para evaluar dicha condición, el protocolo utilizado para aplicar la intervención e identificar en los estudios cuál es el efecto de la terapia sobre la intensidad del dolor.

Método

Revisión sistemática y metaanálisis, conducidas entre junio de 2017 y mayo de 2018, en las bases de datos PubMed, CINAHL, PEDro, Embase, Scopus y en la Biblioteca Virtual en Salud. Listas de referencias de revisiones sistemáticas también fueron exploradas.

Resultados

Se localizaron 427 estudios, 15 incluidos en el análisis cualitativo, y siete en el análisis cuantitativo. La acupuntura auricular obtuvo resultados positivos en el 80% de los estudios. Los resultados más utilizados fueron la intensidad y la calidad del dolor, consumo de fármacos, incapacidad física y calidad de vida. No existe estandarización en el protocolo de acupuntura auricular para dolor crónico en la espalda. Los resultados del metaanálisis señalaron que la acupuntura auricular fue eficaz en reducir los scores de intensidad de dolor (p=0,038).

Conclusión

La acupuntura auricular es una práctica prometedora para el tratamiento del dolor crónico en la espalda en adultos.

Dolor Crónico; Dolor de Espalda; Acupuntura Auricular; Terapias Complementarias; Revisión

INTRODUCTION

Chronic back pain, which may affect cervical, thoracic, and/or lumbar regions, presents a considerable individual and social impact on public health11. Steingrímsdóttir ÓA, Landmark T, Macfarlane GJ, Nielsen CS. Defining chronic pain in epidemiological studies: a systematic review and meta-analysis. Pain. 2017;158(11):2092-107. . Between the 1990s and 2013, lower back pain ranked first and cervical fourth among the 25 overall causes of years living with a disability, according to the Global Burden of Disease Study22. Vos T, Barber RN, Bell B, Bertozzi-Villa A, Biryukov S, Bolliger I, et al. Global, regional, and national incidence, prevalence, and years lived with disability for 301 acute and chronic diseases and injuries in 188 countries, 1990–2013: a systematic analysis for the Global Burden of Disease Study 2013. Lancet. 2015;386(9995):743-800. .

In the last 10 years, lower back pain increased 18%, being considered one of the most common musculoskeletal disorders in current society33. Lim TK, Ma Y, Berger F, Litscher G. Acupuncture and neural mechanism in the management of low back pain-an update. Medicines (Basel). 2018;5(3):1-34. . Regarding cervical pain, yearly prevalence is higher than 30%44. Cohen SP. Epidemiology, diagnosis, and treatment of neck pain. Mayo Clin Proc. 2015;90(2):284-99. . As for the thoracic region, however, epidemiological characteristics have not been well-documented; yet, this prevalence varies from 4.8% to 7%, approximately55. Briggs AM, Smith AJ, Straker LM, Bragge P. Thoracic spine pain in the general population: prevalence, incidence and associated factors in children, adolescents and adults. A systematic review. BMC Musculoskelet Disord [Internet]. 2009 [cited 2018 Jul 10];10:77. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2720379/
https://www.ncbi.nlm.nih.gov/pmc/article...
.

The most current international guidelines recommend drug management for relieving back pain. However, most drugs produce limited relief and several serious side-effects. In this regard, a movement towards non-pharmacological approaches becomes necessary, including multidisciplinary rehabilitation based on physical therapy, massage therapy, cognitive behavior therapy, acupuncture, among others33. Lim TK, Ma Y, Berger F, Litscher G. Acupuncture and neural mechanism in the management of low back pain-an update. Medicines (Basel). 2018;5(3):1-34. .

Auricular acupuncture (AA) is an adjuvant therapy to the regular acupuncture treatment. It has been used as a therapeutic approach in China since the Han dynasty, and a modern version of the technique was developed at the end of the 1950s66. Zhao HJ, Tan JY, Wang T, Jin L. Auricular therapy for chronic pain management in adults: A synthesis of evidence. Complement Ther Clin Pract. 2015;21(2):68-78. , which consists of a method for diagnosis and treatment of physical and psychosomatic disorders by stimulating specific areas of the ear77. Gori L, Firenzuoli F. Ear acupuncture in European traditional medicine. Evid Based Complement Alternat Med [Internet]. 2007 [cited 2018 May 17];4 Suppl 1:13-6. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2206232/
https://www.ncbi.nlm.nih.gov/pmc/article...
. The effects of the intervention have been explained by neurophysiology and reflexology77. Gori L, Firenzuoli F. Ear acupuncture in European traditional medicine. Evid Based Complement Alternat Med [Internet]. 2007 [cited 2018 May 17];4 Suppl 1:13-6. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2206232/
https://www.ncbi.nlm.nih.gov/pmc/article...
. The technique has already been tested for the control of chronic pain66. Zhao HJ, Tan JY, Wang T, Jin L. Auricular therapy for chronic pain management in adults: A synthesis of evidence. Complement Ther Clin Pract. 2015;21(2):68-78. , however, due to heterogeneity and methodological failures in randomized clinical trials (RCT), the evidence on AA for its management is incipient66. Zhao HJ, Tan JY, Wang T, Jin L. Auricular therapy for chronic pain management in adults: A synthesis of evidence. Complement Ther Clin Pract. 2015;21(2):68-78. . In addition, despite having a synthesis of the evidence in the literature on the effects of acupuncture in specific segments of the spine, mainly in the lumbar region88. Zeng Y, Chung JW. Acupuncture for chronic nonspecific low back pain: an overview of systematic reviews. Evid Based Complement Alternat Med [Internet]. 2015 [cited 2018 May 17]:328196. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4364128/
https://www.ncbi.nlm.nih.gov/pmc/article...
- 99. Liu L, Skinner M, McDonough S, Mabire L, Baxter GD. Acupuncture for low back pain: an overview of systematic reviews. Evid Based Complement Alternat Med [Internet]. 2015 [cited 2018 Jul 10];328196. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4364128/
https://www.ncbi.nlm.nih.gov/pmc/article...
, up to the present moment, systematic analyses designed specifically for investigating AA effects for chronic pain in all segments of the spine (cervical, thoracic, and/or lumbar) have not been identified.

Therefore, the objective of this study was to investigate and analyze RCT found in the literature on the action of AA for chronic back pain in adults, and to identify the most commonly used outcomes for assessing this condition, the protocol used for applying the intervention, and the effect of the therapy on pain intensity in these studies.

METHOD

A systematic literature review and a metanalysis were developed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA Statement) criteria.1010. Moher D, Liberati A, Tetzlaff J, Altman DG, The PRISMA Group. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA Statement. PLoS Med [Internet]. 2009 [cited 2018 May 17];6(7):1-6. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2707599/
https://www.ncbi.nlm.nih.gov/pmc/article...

The PICO (P – population; I – intervention; C – comparison; O – outcomes)1111. Higgins JPT, Green S, editors. Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0. [Internet]. Londes: The Cochrane Collaboration; 2011 [cited 2018 May 17]. Available from: http://handbook-5-1.cochrane.org/
http://handbook-5-1.cochrane.org/...
strategy was used to formulate the guiding question: “What are the effects of auricular acupuncture for chronic pain in adults?”

The search for articles, conducted by two independent reviewers with the help of a librarian in the field of health sciences, was carried out using the following databases: Medline via PUBMED, Web of Science, the Cumulative Index to Nursing and Allied Health Literature (CINAHL), Physiotherapy Evidence Database (PEDro), Embase, Scopus, and databases indexed in the Virtual Health Library (VHL), such as the Latin American and Caribbean Center on Health Sciences Information (LILACS), the Brazilian Nursing Database (BDENF), and the National Center of Information of Medical Sciences of Cuba (CUMED). Reference lists of systematic reviews were also used for searching relevant studies related to the guiding question. All searches in the electronic databases were carried out in May 2018.

Controlled descriptors, extracted from the Health Sciences Descriptors (DeCS) and from the Medical Subject Headings (MeSH), and uncontrolled descriptors were combined using Boolean operators OR and AND as follows: (“Back Pain” OR “Low Back Pain” OR Sciatica OR “Chronic Pain” OR “Musculoskeletal Pain” OR “Myalgia” OR “Neck Pain” OR Lumbago OR “lumbar pain” OR “Low Back Pains” OR “Musculoskeletal Pains” OR “Muscle Pain” OR “Neck Pains” OR “Cervical Pain” OR “Cervical Pains”) AND (“Auricular Acupuncture” OR “Ear Acupuncture” OR “Auricular Acupunctures” OR auriculopressure). The search strategy was adapted for each electronic database, and the terminologies were searched in all fields (title/abstract/descriptors/text).

The eligibility criteria for selection of articles, based on the PICO strategy, were: RCT with adults (18 years or over) ( population ); use of auricular acupuncture (puncture, pressure, electrical stimulation, magnetic stimulation, among others) ( intervention ); comparison with one or more of the following groups: sham, waiting list, standard medical treatment/active treatment or no treatment ( comparison ); and chronic pain (3 months or more)1212. Merskey H, Bogduk N, ditors. Classification of chronic pain: descriptions of chronic pain syndromes and definitions of pain terms. 2nded. Washington: IASP; 2002. in at least one of the spine segments (cervical, thoracic, and/or lumbar) ( outcomes ). The studies excluded were those that did not provide the full abstract online, those that were not located by any means, and studies with pregnant women. It should be noted that there were no restrictions on the year of publication and the language of the analyzed studies.

The data of the studies included in the review were extracted by two independent researchers, using a standardized data collection form,1313. Moura CC, Carvalho CC, Silva AM, Iunes DH, Carvalho EC, Chaves ECL. Auriculoterapia efeito sobre a ansiedade. Rev Cuba Enf [Internet]. 2014 [citado 2018 maio 18];30(2):1-15. Disponible en: http://www.medigraphic.com/pdfs/revcubenf/cnf-2014/cnf142e.pdf
http://www.medigraphic.com/pdfs/revcuben...
and adapted by the study researchers. The following data were extracted: article identification (title, author(s)/area of study, journal, year of publication, country/study language); objectives; methodological characteristics (design, sample size, loss to follow-up; inclusion and exclusion criteria); clinical data (number of patients by gender, age, diagnosis, duration of symptoms); description of interventions in the follow-up groups (treatment line, number of sessions, treatment duration, application device, time the device was kept on, application points, unilateral or bilateral application, location of the points, type of protocol, professional who performed the intervention, years of experience in the field; outcomes and assessment methods (number of evaluations, intervals among them, measuring tools); data analysis; main results; and conclusions. A third researcher cross-checked the information collected to reach a final consensus on the extracted data.

The methodological quality of the eligible studies was assessed using the Jadad scale1414. Jadad AR, Moore RA, Carroll D, Jenkinson C, Reynolds DJ, Gavaghan DJ, et al. Assessing the quality of reports of randomized clinical trials: is blinding necessary?. Control Clin Trials. 1996;17(1):1-12. , which focuses on internal validity. The questions have yes or no answer options, with a total score of five points: three questions are given one point each for affirmative answers, and two additional points are given to appropriate methods of randomization and allocation confidentiality1010. Moher D, Liberati A, Tetzlaff J, Altman DG, The PRISMA Group. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA Statement. PLoS Med [Internet]. 2009 [cited 2018 May 17];6(7):1-6. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2707599/
https://www.ncbi.nlm.nih.gov/pmc/article...
. Two independent reviewers carried out the evaluation, and a third researcher was consulted to solve possible differences.

Data analyses were carried out using the Stata SE/12.0 statistical software. The absolute difference among the means, with a 95% confidence interval, was selected to describe the mean differences among the treated groups and the assessment control carried out at the end of the treatment. A p<005 value was considered statistically significant. The potential heterogeneity among the studies was checked using the Cochran’s Q1515. Lau J, Ioannidis JP, Schmid CH. Quantitative synthesis in systematic reviews. Ann Intern Med. 1997;127(9):820-6. and the I22. Vos T, Barber RN, Bell B, Bertozzi-Villa A, Biryukov S, Bolliger I, et al. Global, regional, and national incidence, prevalence, and years lived with disability for 301 acute and chronic diseases and injuries in 188 countries, 1990–2013: a systematic analysis for the Global Burden of Disease Study 2013. Lancet. 2015;386(9995):743-800. statistical tests. Because the heterogeneity results in the test were statistically significant (p<0.05) and the calculated value of I22. Vos T, Barber RN, Bell B, Bertozzi-Villa A, Biryukov S, Bolliger I, et al. Global, regional, and national incidence, prevalence, and years lived with disability for 301 acute and chronic diseases and injuries in 188 countries, 1990–2013: a systematic analysis for the Global Burden of Disease Study 2013. Lancet. 2015;386(9995):743-800. suggested high heterogeneity (86.8%)1616. Higgins JPT, Thompson SG. Quantifying heterogeneity in a meta-analysis. Statist Med. 2002;21:1539-58. , the model of random effects was adopted for the analysis.

RESULTS

A total of 427 studies were found in the electronic and manual searches. Because they were duplicated, 161 studies were removed from the list. After reviewing their titles and abstracts, 225 articles were excluded, whereas 41 remained for full text analysis. Out of these, the texts of four studies were not located (online, through bibliographic commutation, or direct contact with the authors), and 22 articles were excluded. Thus, 15 articles were included in the synthesis of the qualitative analysis, and seven in the quantitative analysis ( Figure 1 ).

Figure 1
– Flowchart of article selection for the systematic review – Belo Horizonte, MG, Brasil, 2018.

A total of 930 individuals participated in the selected studies, with age varying from 18 to 90 years of age, whereas 462 were in the groups that received auricular acupuncture, and 468 were in the control groups. All participants presented chronic pain conditions88. Zeng Y, Chung JW. Acupuncture for chronic nonspecific low back pain: an overview of systematic reviews. Evid Based Complement Alternat Med [Internet]. 2015 [cited 2018 May 17]:328196. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4364128/
https://www.ncbi.nlm.nih.gov/pmc/article...
, whereas the lumbar spine was the most affected region (n=10),1717. Ushinohama A, Cunha BP, Costa LO, Barela AM, Freitas PB. Effect of a single session of ear acupuncture on pain intensity and postural control in individuals with chronic low back pain: a randomized controlled trial. Braz J Phys Ther. 2016;20(4):328-35.

18. Yeh CH, Kwai-Ping Suen L, Chien LC, Margolis L, Liang Z, Glick RM, et al. Day-to-day changes of auricular point acupressure to manage chronic low back pain: a 29-day randomized controlled study. Pain Med. 2015;16(10):1857-69.

19. Yeh CH, Morone NE, Chien LC, Cao Y, Lu H, Shen J, et al. Auricular point acupressure to manage chronic low back pain in older adults: a randomizedcontrolled pilot study. Evid Based Complement Alternat Med [Internet]. 2014 [cited 2018 May 13];2014:1-11. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4134789/
https://www.ncbi.nlm.nih.gov/pmc/article...

20. Marignan M. Auriculotherapy treatment protocol for low-back pain: a randomized trial. Med Acupunct. 2014;26(3):154-60.

21. Yeh CH, Chien LC, Balaban D, Sponberg R, Primavera J, Morone NE, et al. A randomized clinical trial of auricular point acupressure for chronic low back pain: a feasibility study. Evid Based Complement Alternat Med [Internet]. 2013 [cited 2018 May 17];2013:1-9. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3603381/
https://www.ncbi.nlm.nih.gov/pmc/article...

22. Hunter RF, McDonough SM, Bradbury I, Liddle SD, Walsh DM, Dhamija S, et al. Exercise and auricular acupuncture for chronic low-back pain: a feasibility randomized-controlled trial. Clin J Pain. 2012;28(3):259-67.

23. Zhangxiu X, Limin Y, Yan Z, Liuyan S, Changyu M, Shangjie C, et al. Effect of auricular point sticking on pain due to lumbar strain. J Acupunct Tuina Sci. 2011;9(6):384-7.

24. Suen LK, Wong EM. Longitudinal changes in the disability level of the elders with low back pain after auriculotherapy. Complement Ther Med. 2008;16(1):28-35.

25. Suen LK, Wong TK, Chung JW, Yip VY. Auriculotherapy on low back pain in the elderly. Complement Ther Clin Pract. 2007;13(1):63-9.
- 2626. Sator-Katzenschlager SM, Scharbert G, Kozek-Langenecker SA, Szeles JC, Finster G, Schiesser AW, et al. The short- and long-term benefit in chronic low back pain through adjuvant electrical versus manual auricular acupuncture. Anesth Analg. 2004;98(5):1359-64. followed by the cervical region (n=3)2727. Silva AC, Biasotto-Gonzalez DA, Santos DM, Melo NC, Gomes CA, Amorim CF, et al. Evaluation of the immediate effect of auricular acupuncture on pain and electromyographic activity of the upper trapezius muscle in patients with nonspecific neck pain: a randomized, single-blinded, sham-controlled, crossover study. Evid Based Complement Alternat Med [Internet]. 2015 [cited 2018 May 18];2015:1-8. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4588355/
https://www.ncbi.nlm.nih.gov/pmc/article...

28. Ceccherelli F, Tortora P, Nassimbeni C, Casale R, Gagliardi G, Giron G. The therapeutic efficacy of somatic acupuncture is not increased by auriculotherapy: a randomised, blind control study in cervical myofascial pain. Complement Ther Med. 2006;14(1):47-52.
- 2929. Sator-Katzenschlager SM, Szeles JC, Scharbert G, Michalek-Sauberer A, Kober A, Heinze G, Kozek-Langenecker SA. Electrical stimulation of auricular acupuncture points is more effective than conventional manual auricular acupuncture in chronic cervical pain: a pilot study. Anesth Analg. 2003;97(5):1469-73. , and the dorsal region as a whole (n=2)3030. Eberhardt TD, Hofstätter LM, Lopes SMS, Silva EAA, Ceranto DCFB, Nicola AL. Analgesic comparison of Zen Shiatsu and auricular acupuncture in back pain among nursing professionals. Rev Enferm UERJ [Internet]. 2015 [cited 2018 May 18]; 23(3):324-30. Available from: http://www.e-publicacoes.uerj.br/index.php/enfermagemuerj/article/view/9616/18295
http://www.e-publicacoes.uerj.br/index.p...
- 3131. Vas J, Modesto M, Aguilar I, Gonçalo CS, Rivas-Ruiz F. Eficacia y seguridad de la auriculopresión en pacientes de atención primaria con raquialgia crónica no específica: estudio multicéntrico controlado aleatorizado. Rev Int Acupuntura. 2014;8(3):77-86. .

Chart 1 shows the characterization of the studies regarding the interventions applied in the experimental and control groups and their main findings.

Chart 1
– Characterization of the studies regarding the applied intervention – Belo Horizonte, MG, Brazil, 2018.

Regarding the RCT methodological quality, all studies reported using the random sequence generation method, and in just three this process was not appropriate2323. Zhangxiu X, Limin Y, Yan Z, Liuyan S, Changyu M, Shangjie C, et al. Effect of auricular point sticking on pain due to lumbar strain. J Acupunct Tuina Sci. 2011;9(6):384-7.

24. Suen LK, Wong EM. Longitudinal changes in the disability level of the elders with low back pain after auriculotherapy. Complement Ther Med. 2008;16(1):28-35.
- 2525. Suen LK, Wong TK, Chung JW, Yip VY. Auriculotherapy on low back pain in the elderly. Complement Ther Clin Pract. 2007;13(1):63-9. . In two RCT1313. Moura CC, Carvalho CC, Silva AM, Iunes DH, Carvalho EC, Chaves ECL. Auriculoterapia efeito sobre a ansiedade. Rev Cuba Enf [Internet]. 2014 [citado 2018 maio 18];30(2):1-15. Disponible en: http://www.medigraphic.com/pdfs/revcubenf/cnf-2014/cnf142e.pdf
http://www.medigraphic.com/pdfs/revcuben...

14. Jadad AR, Moore RA, Carroll D, Jenkinson C, Reynolds DJ, Gavaghan DJ, et al. Assessing the quality of reports of randomized clinical trials: is blinding necessary?. Control Clin Trials. 1996;17(1):1-12.

15. Lau J, Ioannidis JP, Schmid CH. Quantitative synthesis in systematic reviews. Ann Intern Med. 1997;127(9):820-6.

16. Higgins JPT, Thompson SG. Quantifying heterogeneity in a meta-analysis. Statist Med. 2002;21:1539-58.

17. Ushinohama A, Cunha BP, Costa LO, Barela AM, Freitas PB. Effect of a single session of ear acupuncture on pain intensity and postural control in individuals with chronic low back pain: a randomized controlled trial. Braz J Phys Ther. 2016;20(4):328-35.

18. Yeh CH, Kwai-Ping Suen L, Chien LC, Margolis L, Liang Z, Glick RM, et al. Day-to-day changes of auricular point acupressure to manage chronic low back pain: a 29-day randomized controlled study. Pain Med. 2015;16(10):1857-69.

19. Yeh CH, Morone NE, Chien LC, Cao Y, Lu H, Shen J, et al. Auricular point acupressure to manage chronic low back pain in older adults: a randomizedcontrolled pilot study. Evid Based Complement Alternat Med [Internet]. 2014 [cited 2018 May 13];2014:1-11. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4134789/
https://www.ncbi.nlm.nih.gov/pmc/article...

20. Marignan M. Auriculotherapy treatment protocol for low-back pain: a randomized trial. Med Acupunct. 2014;26(3):154-60.

21. Yeh CH, Chien LC, Balaban D, Sponberg R, Primavera J, Morone NE, et al. A randomized clinical trial of auricular point acupressure for chronic low back pain: a feasibility study. Evid Based Complement Alternat Med [Internet]. 2013 [cited 2018 May 17];2013:1-9. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3603381/
https://www.ncbi.nlm.nih.gov/pmc/article...

22. Hunter RF, McDonough SM, Bradbury I, Liddle SD, Walsh DM, Dhamija S, et al. Exercise and auricular acupuncture for chronic low-back pain: a feasibility randomized-controlled trial. Clin J Pain. 2012;28(3):259-67.

23. Zhangxiu X, Limin Y, Yan Z, Liuyan S, Changyu M, Shangjie C, et al. Effect of auricular point sticking on pain due to lumbar strain. J Acupunct Tuina Sci. 2011;9(6):384-7.

24. Suen LK, Wong EM. Longitudinal changes in the disability level of the elders with low back pain after auriculotherapy. Complement Ther Med. 2008;16(1):28-35.

25. Suen LK, Wong TK, Chung JW, Yip VY. Auriculotherapy on low back pain in the elderly. Complement Ther Clin Pract. 2007;13(1):63-9.

26. Sator-Katzenschlager SM, Scharbert G, Kozek-Langenecker SA, Szeles JC, Finster G, Schiesser AW, et al. The short- and long-term benefit in chronic low back pain through adjuvant electrical versus manual auricular acupuncture. Anesth Analg. 2004;98(5):1359-64.

27. Silva AC, Biasotto-Gonzalez DA, Santos DM, Melo NC, Gomes CA, Amorim CF, et al. Evaluation of the immediate effect of auricular acupuncture on pain and electromyographic activity of the upper trapezius muscle in patients with nonspecific neck pain: a randomized, single-blinded, sham-controlled, crossover study. Evid Based Complement Alternat Med [Internet]. 2015 [cited 2018 May 18];2015:1-8. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4588355/
https://www.ncbi.nlm.nih.gov/pmc/article...

28. Ceccherelli F, Tortora P, Nassimbeni C, Casale R, Gagliardi G, Giron G. The therapeutic efficacy of somatic acupuncture is not increased by auriculotherapy: a randomised, blind control study in cervical myofascial pain. Complement Ther Med. 2006;14(1):47-52.

29. Sator-Katzenschlager SM, Szeles JC, Scharbert G, Michalek-Sauberer A, Kober A, Heinze G, Kozek-Langenecker SA. Electrical stimulation of auricular acupuncture points is more effective than conventional manual auricular acupuncture in chronic cervical pain: a pilot study. Anesth Analg. 2003;97(5):1469-73.
- 3030. Eberhardt TD, Hofstätter LM, Lopes SMS, Silva EAA, Ceranto DCFB, Nicola AL. Analgesic comparison of Zen Shiatsu and auricular acupuncture in back pain among nursing professionals. Rev Enferm UERJ [Internet]. 2015 [cited 2018 May 18]; 23(3):324-30. Available from: http://www.e-publicacoes.uerj.br/index.php/enfermagemuerj/article/view/9616/18295
http://www.e-publicacoes.uerj.br/index.p...
there was no description of masking, and in other two2424. Suen LK, Wong EM. Longitudinal changes in the disability level of the elders with low back pain after auriculotherapy. Complement Ther Med. 2008;16(1):28-35. - 2525. Suen LK, Wong TK, Chung JW, Yip VY. Auriculotherapy on low back pain in the elderly. Complement Ther Clin Pract. 2007;13(1):63-9. this masking was considered inadequate. There was no description of loss to follow-up in three RCT2020. Marignan M. Auriculotherapy treatment protocol for low-back pain: a randomized trial. Med Acupunct. 2014;26(3):154-60. , 2323. Zhangxiu X, Limin Y, Yan Z, Liuyan S, Changyu M, Shangjie C, et al. Effect of auricular point sticking on pain due to lumbar strain. J Acupunct Tuina Sci. 2011;9(6):384-7. , 2727. Silva AC, Biasotto-Gonzalez DA, Santos DM, Melo NC, Gomes CA, Amorim CF, et al. Evaluation of the immediate effect of auricular acupuncture on pain and electromyographic activity of the upper trapezius muscle in patients with nonspecific neck pain: a randomized, single-blinded, sham-controlled, crossover study. Evid Based Complement Alternat Med [Internet]. 2015 [cited 2018 May 18];2015:1-8. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4588355/
https://www.ncbi.nlm.nih.gov/pmc/article...
. Therefore, 90% (n=9) of the studies1717. Ushinohama A, Cunha BP, Costa LO, Barela AM, Freitas PB. Effect of a single session of ear acupuncture on pain intensity and postural control in individuals with chronic low back pain: a randomized controlled trial. Braz J Phys Ther. 2016;20(4):328-35.

18. Yeh CH, Kwai-Ping Suen L, Chien LC, Margolis L, Liang Z, Glick RM, et al. Day-to-day changes of auricular point acupressure to manage chronic low back pain: a 29-day randomized controlled study. Pain Med. 2015;16(10):1857-69.
- 1919. Yeh CH, Morone NE, Chien LC, Cao Y, Lu H, Shen J, et al. Auricular point acupressure to manage chronic low back pain in older adults: a randomizedcontrolled pilot study. Evid Based Complement Alternat Med [Internet]. 2014 [cited 2018 May 13];2014:1-11. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4134789/
https://www.ncbi.nlm.nih.gov/pmc/article...
, 2121. Yeh CH, Chien LC, Balaban D, Sponberg R, Primavera J, Morone NE, et al. A randomized clinical trial of auricular point acupressure for chronic low back pain: a feasibility study. Evid Based Complement Alternat Med [Internet]. 2013 [cited 2018 May 17];2013:1-9. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3603381/
https://www.ncbi.nlm.nih.gov/pmc/article...
- 2222. Hunter RF, McDonough SM, Bradbury I, Liddle SD, Walsh DM, Dhamija S, et al. Exercise and auricular acupuncture for chronic low-back pain: a feasibility randomized-controlled trial. Clin J Pain. 2012;28(3):259-67. , 2626. Sator-Katzenschlager SM, Scharbert G, Kozek-Langenecker SA, Szeles JC, Finster G, Schiesser AW, et al. The short- and long-term benefit in chronic low back pain through adjuvant electrical versus manual auricular acupuncture. Anesth Analg. 2004;98(5):1359-64. , 2828. Ceccherelli F, Tortora P, Nassimbeni C, Casale R, Gagliardi G, Giron G. The therapeutic efficacy of somatic acupuncture is not increased by auriculotherapy: a randomised, blind control study in cervical myofascial pain. Complement Ther Med. 2006;14(1):47-52. - 2929. Sator-Katzenschlager SM, Szeles JC, Scharbert G, Michalek-Sauberer A, Kober A, Heinze G, Kozek-Langenecker SA. Electrical stimulation of auricular acupuncture points is more effective than conventional manual auricular acupuncture in chronic cervical pain: a pilot study. Anesth Analg. 2003;97(5):1469-73. , 3131. Vas J, Modesto M, Aguilar I, Gonçalo CS, Rivas-Ruiz F. Eficacia y seguridad de la auriculopresión en pacientes de atención primaria con raquialgia crónica no específica: estudio multicéntrico controlado aleatorizado. Rev Int Acupuntura. 2014;8(3):77-86. obtained score five in the Jadad score; 13.3% (n=2)2020. Marignan M. Auriculotherapy treatment protocol for low-back pain: a randomized trial. Med Acupunct. 2014;26(3):154-60. , 2727. Silva AC, Biasotto-Gonzalez DA, Santos DM, Melo NC, Gomes CA, Amorim CF, et al. Evaluation of the immediate effect of auricular acupuncture on pain and electromyographic activity of the upper trapezius muscle in patients with nonspecific neck pain: a randomized, single-blinded, sham-controlled, crossover study. Evid Based Complement Alternat Med [Internet]. 2015 [cited 2018 May 18];2015:1-8. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4588355/
https://www.ncbi.nlm.nih.gov/pmc/article...
obtained score four; 6.7% (n=1)3030. Eberhardt TD, Hofstätter LM, Lopes SMS, Silva EAA, Ceranto DCFB, Nicola AL. Analgesic comparison of Zen Shiatsu and auricular acupuncture in back pain among nursing professionals. Rev Enferm UERJ [Internet]. 2015 [cited 2018 May 18]; 23(3):324-30. Available from: http://www.e-publicacoes.uerj.br/index.php/enfermagemuerj/article/view/9616/18295
http://www.e-publicacoes.uerj.br/index.p...
obtained score three; and 20% (n=3)2121. Yeh CH, Chien LC, Balaban D, Sponberg R, Primavera J, Morone NE, et al. A randomized clinical trial of auricular point acupressure for chronic low back pain: a feasibility study. Evid Based Complement Alternat Med [Internet]. 2013 [cited 2018 May 17];2013:1-9. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3603381/
https://www.ncbi.nlm.nih.gov/pmc/article...

22. Hunter RF, McDonough SM, Bradbury I, Liddle SD, Walsh DM, Dhamija S, et al. Exercise and auricular acupuncture for chronic low-back pain: a feasibility randomized-controlled trial. Clin J Pain. 2012;28(3):259-67.

23. Zhangxiu X, Limin Y, Yan Z, Liuyan S, Changyu M, Shangjie C, et al. Effect of auricular point sticking on pain due to lumbar strain. J Acupunct Tuina Sci. 2011;9(6):384-7.

24. Suen LK, Wong EM. Longitudinal changes in the disability level of the elders with low back pain after auriculotherapy. Complement Ther Med. 2008;16(1):28-35.
- 2525. Suen LK, Wong TK, Chung JW, Yip VY. Auriculotherapy on low back pain in the elderly. Complement Ther Clin Pract. 2007;13(1):63-9. obtained score one.

Study outcomes and the way of measuring them, the number of evaluations, and the interval between them are described in Chart 2 .

Chart 2
– Evaluated outcomes, measuring tools, number of evaluations, and interval between them. Belo Horizonte, MG, Brazil, 2018.

Pain intensity was addressed in all studies. The second most evaluated outcome was drug consumption, identified in 46.6% (n=7) of the studies1818. Yeh CH, Kwai-Ping Suen L, Chien LC, Margolis L, Liang Z, Glick RM, et al. Day-to-day changes of auricular point acupressure to manage chronic low back pain: a 29-day randomized controlled study. Pain Med. 2015;16(10):1857-69. - 1919. Yeh CH, Morone NE, Chien LC, Cao Y, Lu H, Shen J, et al. Auricular point acupressure to manage chronic low back pain in older adults: a randomizedcontrolled pilot study. Evid Based Complement Alternat Med [Internet]. 2014 [cited 2018 May 13];2014:1-11. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4134789/
https://www.ncbi.nlm.nih.gov/pmc/article...
, 2121. Yeh CH, Chien LC, Balaban D, Sponberg R, Primavera J, Morone NE, et al. A randomized clinical trial of auricular point acupressure for chronic low back pain: a feasibility study. Evid Based Complement Alternat Med [Internet]. 2013 [cited 2018 May 17];2013:1-9. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3603381/
https://www.ncbi.nlm.nih.gov/pmc/article...
- 2222. Hunter RF, McDonough SM, Bradbury I, Liddle SD, Walsh DM, Dhamija S, et al. Exercise and auricular acupuncture for chronic low-back pain: a feasibility randomized-controlled trial. Clin J Pain. 2012;28(3):259-67. , 2626. Sator-Katzenschlager SM, Scharbert G, Kozek-Langenecker SA, Szeles JC, Finster G, Schiesser AW, et al. The short- and long-term benefit in chronic low back pain through adjuvant electrical versus manual auricular acupuncture. Anesth Analg. 2004;98(5):1359-64. , 2929. Sator-Katzenschlager SM, Szeles JC, Scharbert G, Michalek-Sauberer A, Kober A, Heinze G, Kozek-Langenecker SA. Electrical stimulation of auricular acupuncture points is more effective than conventional manual auricular acupuncture in chronic cervical pain: a pilot study. Anesth Analg. 2003;97(5):1469-73. , 3131. Vas J, Modesto M, Aguilar I, Gonçalo CS, Rivas-Ruiz F. Eficacia y seguridad de la auriculopresión en pacientes de atención primaria con raquialgia crónica no específica: estudio multicéntrico controlado aleatorizado. Rev Int Acupuntura. 2014;8(3):77-86. , followed by physical disability (33.3%; n=5)1717. Ushinohama A, Cunha BP, Costa LO, Barela AM, Freitas PB. Effect of a single session of ear acupuncture on pain intensity and postural control in individuals with chronic low back pain: a randomized controlled trial. Braz J Phys Ther. 2016;20(4):328-35. , 1919. Yeh CH, Morone NE, Chien LC, Cao Y, Lu H, Shen J, et al. Auricular point acupressure to manage chronic low back pain in older adults: a randomizedcontrolled pilot study. Evid Based Complement Alternat Med [Internet]. 2014 [cited 2018 May 13];2014:1-11. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4134789/
https://www.ncbi.nlm.nih.gov/pmc/article...
, 2121. Yeh CH, Chien LC, Balaban D, Sponberg R, Primavera J, Morone NE, et al. A randomized clinical trial of auricular point acupressure for chronic low back pain: a feasibility study. Evid Based Complement Alternat Med [Internet]. 2013 [cited 2018 May 17];2013:1-9. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3603381/
https://www.ncbi.nlm.nih.gov/pmc/article...
- 2222. Hunter RF, McDonough SM, Bradbury I, Liddle SD, Walsh DM, Dhamija S, et al. Exercise and auricular acupuncture for chronic low-back pain: a feasibility randomized-controlled trial. Clin J Pain. 2012;28(3):259-67. , 2424. Suen LK, Wong EM. Longitudinal changes in the disability level of the elders with low back pain after auriculotherapy. Complement Ther Med. 2008;16(1):28-35. , quality of pain (33.3%; n=5)1919. Yeh CH, Morone NE, Chien LC, Cao Y, Lu H, Shen J, et al. Auricular point acupressure to manage chronic low back pain in older adults: a randomizedcontrolled pilot study. Evid Based Complement Alternat Med [Internet]. 2014 [cited 2018 May 13];2014:1-11. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4134789/
https://www.ncbi.nlm.nih.gov/pmc/article...
, 2323. Zhangxiu X, Limin Y, Yan Z, Liuyan S, Changyu M, Shangjie C, et al. Effect of auricular point sticking on pain due to lumbar strain. J Acupunct Tuina Sci. 2011;9(6):384-7. , 2626. Sator-Katzenschlager SM, Scharbert G, Kozek-Langenecker SA, Szeles JC, Finster G, Schiesser AW, et al. The short- and long-term benefit in chronic low back pain through adjuvant electrical versus manual auricular acupuncture. Anesth Analg. 2004;98(5):1359-64. , 2828. Ceccherelli F, Tortora P, Nassimbeni C, Casale R, Gagliardi G, Giron G. The therapeutic efficacy of somatic acupuncture is not increased by auriculotherapy: a randomised, blind control study in cervical myofascial pain. Complement Ther Med. 2006;14(1):47-52. , 3131. Vas J, Modesto M, Aguilar I, Gonçalo CS, Rivas-Ruiz F. Eficacia y seguridad de la auriculopresión en pacientes de atención primaria con raquialgia crónica no específica: estudio multicéntrico controlado aleatorizado. Rev Int Acupuntura. 2014;8(3):77-86. , and quality of life (26.6%; n=4)1919. Yeh CH, Morone NE, Chien LC, Cao Y, Lu H, Shen J, et al. Auricular point acupressure to manage chronic low back pain in older adults: a randomizedcontrolled pilot study. Evid Based Complement Alternat Med [Internet]. 2014 [cited 2018 May 13];2014:1-11. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4134789/
https://www.ncbi.nlm.nih.gov/pmc/article...
, 2121. Yeh CH, Chien LC, Balaban D, Sponberg R, Primavera J, Morone NE, et al. A randomized clinical trial of auricular point acupressure for chronic low back pain: a feasibility study. Evid Based Complement Alternat Med [Internet]. 2013 [cited 2018 May 17];2013:1-9. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3603381/
https://www.ncbi.nlm.nih.gov/pmc/article...
- 2222. Hunter RF, McDonough SM, Bradbury I, Liddle SD, Walsh DM, Dhamija S, et al. Exercise and auricular acupuncture for chronic low-back pain: a feasibility randomized-controlled trial. Clin J Pain. 2012;28(3):259-67. , 3131. Vas J, Modesto M, Aguilar I, Gonçalo CS, Rivas-Ruiz F. Eficacia y seguridad de la auriculopresión en pacientes de atención primaria con raquialgia crónica no específica: estudio multicéntrico controlado aleatorizado. Rev Int Acupuntura. 2014;8(3):77-86. ( Chart 2 ).

The characteristics of the protocol for AA intervention are described in Chart 3 , based on the recommendations provided by the Revised Standards for Reporting Interventions in Clinical Trials of Acupuncture (STRICTA)3232. MacPherson H, Altman DG, Hammerschlag R, Youping L, Taixiang W, White A, et al. Revised Standards for Reporting Interventions in Clinical Trials of Acupuncture (STRICTA): extending the CONSORT statement. PLoS Med [Internet]. 2010 [cited 2018 May 18];7(6):1-11. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2882429/
https://www.ncbi.nlm.nih.gov/pmc/article...
.

Chart 3
– Auricular acupuncture intervention protocol for treating chronic back pain – Belo Horizonte, MG, Brazil, 2018.

Only 6.7% (n=1) of the studies3131. Vas J, Modesto M, Aguilar I, Gonçalo CS, Rivas-Ruiz F. Eficacia y seguridad de la auriculopresión en pacientes de atención primaria con raquialgia crónica no específica: estudio multicéntrico controlado aleatorizado. Rev Int Acupuntura. 2014;8(3):77-86. carried out the intervention in an individualized format. In all the others (93.3%; n=14), the intervention took place with fixed treatment protocols.

In 26.6% (n=4) of the studies1818. Yeh CH, Kwai-Ping Suen L, Chien LC, Margolis L, Liang Z, Glick RM, et al. Day-to-day changes of auricular point acupressure to manage chronic low back pain: a 29-day randomized controlled study. Pain Med. 2015;16(10):1857-69. - 1919. Yeh CH, Morone NE, Chien LC, Cao Y, Lu H, Shen J, et al. Auricular point acupressure to manage chronic low back pain in older adults: a randomizedcontrolled pilot study. Evid Based Complement Alternat Med [Internet]. 2014 [cited 2018 May 13];2014:1-11. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4134789/
https://www.ncbi.nlm.nih.gov/pmc/article...
, 2121. Yeh CH, Chien LC, Balaban D, Sponberg R, Primavera J, Morone NE, et al. A randomized clinical trial of auricular point acupressure for chronic low back pain: a feasibility study. Evid Based Complement Alternat Med [Internet]. 2013 [cited 2018 May 17];2013:1-9. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3603381/
https://www.ncbi.nlm.nih.gov/pmc/article...
, 3131. Vas J, Modesto M, Aguilar I, Gonçalo CS, Rivas-Ruiz F. Eficacia y seguridad de la auriculopresión en pacientes de atención primaria con raquialgia crónica no específica: estudio multicéntrico controlado aleatorizado. Rev Int Acupuntura. 2014;8(3):77-86. , the intervention was carried out by nurses, followed by physical therapists (20%; n=3)1717. Ushinohama A, Cunha BP, Costa LO, Barela AM, Freitas PB. Effect of a single session of ear acupuncture on pain intensity and postural control in individuals with chronic low back pain: a randomized controlled trial. Braz J Phys Ther. 2016;20(4):328-35. , 2222. Hunter RF, McDonough SM, Bradbury I, Liddle SD, Walsh DM, Dhamija S, et al. Exercise and auricular acupuncture for chronic low-back pain: a feasibility randomized-controlled trial. Clin J Pain. 2012;28(3):259-67. , 2727. Silva AC, Biasotto-Gonzalez DA, Santos DM, Melo NC, Gomes CA, Amorim CF, et al. Evaluation of the immediate effect of auricular acupuncture on pain and electromyographic activity of the upper trapezius muscle in patients with nonspecific neck pain: a randomized, single-blinded, sham-controlled, crossover study. Evid Based Complement Alternat Med [Internet]. 2015 [cited 2018 May 18];2015:1-8. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4588355/
https://www.ncbi.nlm.nih.gov/pmc/article...
, physicians (13.3%; n=2)2828. Ceccherelli F, Tortora P, Nassimbeni C, Casale R, Gagliardi G, Giron G. The therapeutic efficacy of somatic acupuncture is not increased by auriculotherapy: a randomised, blind control study in cervical myofascial pain. Complement Ther Med. 2006;14(1):47-52. , 3131. Vas J, Modesto M, Aguilar I, Gonçalo CS, Rivas-Ruiz F. Eficacia y seguridad de la auriculopresión en pacientes de atención primaria con raquialgia crónica no específica: estudio multicéntrico controlado aleatorizado. Rev Int Acupuntura. 2014;8(3):77-86. , and one therapist without specification of training in the field (n=1; 6.6%)3030. Eberhardt TD, Hofstätter LM, Lopes SMS, Silva EAA, Ceranto DCFB, Nicola AL. Analgesic comparison of Zen Shiatsu and auricular acupuncture in back pain among nursing professionals. Rev Enferm UERJ [Internet]. 2015 [cited 2018 May 18]; 23(3):324-30. Available from: http://www.e-publicacoes.uerj.br/index.php/enfermagemuerj/article/view/9616/18295
http://www.e-publicacoes.uerj.br/index.p...
. In 26.6% of the studies (n=4)2020. Marignan M. Auriculotherapy treatment protocol for low-back pain: a randomized trial. Med Acupunct. 2014;26(3):154-60. , 2323. Zhangxiu X, Limin Y, Yan Z, Liuyan S, Changyu M, Shangjie C, et al. Effect of auricular point sticking on pain due to lumbar strain. J Acupunct Tuina Sci. 2011;9(6):384-7. , 2626. Sator-Katzenschlager SM, Scharbert G, Kozek-Langenecker SA, Szeles JC, Finster G, Schiesser AW, et al. The short- and long-term benefit in chronic low back pain through adjuvant electrical versus manual auricular acupuncture. Anesth Analg. 2004;98(5):1359-64. , 2929. Sator-Katzenschlager SM, Szeles JC, Scharbert G, Michalek-Sauberer A, Kober A, Heinze G, Kozek-Langenecker SA. Electrical stimulation of auricular acupuncture points is more effective than conventional manual auricular acupuncture in chronic cervical pain: a pilot study. Anesth Analg. 2003;97(5):1469-73. , no information was provided.

It is important to note that only 13.3% of the studies (n=2) presented the period of experience of the professional that carried out the intervention, which varied between 111717. Ushinohama A, Cunha BP, Costa LO, Barela AM, Freitas PB. Effect of a single session of ear acupuncture on pain intensity and postural control in individuals with chronic low back pain: a randomized controlled trial. Braz J Phys Ther. 2016;20(4):328-35. and 15 years2727. Silva AC, Biasotto-Gonzalez DA, Santos DM, Melo NC, Gomes CA, Amorim CF, et al. Evaluation of the immediate effect of auricular acupuncture on pain and electromyographic activity of the upper trapezius muscle in patients with nonspecific neck pain: a randomized, single-blinded, sham-controlled, crossover study. Evid Based Complement Alternat Med [Internet]. 2015 [cited 2018 May 18];2015:1-8. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4588355/
https://www.ncbi.nlm.nih.gov/pmc/article...
. Only one study indicated that the intervention was performed by specialized professionals, but did not provide the length of training2222. Hunter RF, McDonough SM, Bradbury I, Liddle SD, Walsh DM, Dhamija S, et al. Exercise and auricular acupuncture for chronic low-back pain: a feasibility randomized-controlled trial. Clin J Pain. 2012;28(3):259-67. .

Auricular acupuncture was able to reduce pain intensity in 80% of the studies(n=12).1717. Ushinohama A, Cunha BP, Costa LO, Barela AM, Freitas PB. Effect of a single session of ear acupuncture on pain intensity and postural control in individuals with chronic low back pain: a randomized controlled trial. Braz J Phys Ther. 2016;20(4):328-35.

18. Yeh CH, Kwai-Ping Suen L, Chien LC, Margolis L, Liang Z, Glick RM, et al. Day-to-day changes of auricular point acupressure to manage chronic low back pain: a 29-day randomized controlled study. Pain Med. 2015;16(10):1857-69.

19. Yeh CH, Morone NE, Chien LC, Cao Y, Lu H, Shen J, et al. Auricular point acupressure to manage chronic low back pain in older adults: a randomizedcontrolled pilot study. Evid Based Complement Alternat Med [Internet]. 2014 [cited 2018 May 13];2014:1-11. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4134789/
https://www.ncbi.nlm.nih.gov/pmc/article...

20. Marignan M. Auriculotherapy treatment protocol for low-back pain: a randomized trial. Med Acupunct. 2014;26(3):154-60.

21. Yeh CH, Chien LC, Balaban D, Sponberg R, Primavera J, Morone NE, et al. A randomized clinical trial of auricular point acupressure for chronic low back pain: a feasibility study. Evid Based Complement Alternat Med [Internet]. 2013 [cited 2018 May 17];2013:1-9. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3603381/
https://www.ncbi.nlm.nih.gov/pmc/article...

22. Hunter RF, McDonough SM, Bradbury I, Liddle SD, Walsh DM, Dhamija S, et al. Exercise and auricular acupuncture for chronic low-back pain: a feasibility randomized-controlled trial. Clin J Pain. 2012;28(3):259-67.

23. Zhangxiu X, Limin Y, Yan Z, Liuyan S, Changyu M, Shangjie C, et al. Effect of auricular point sticking on pain due to lumbar strain. J Acupunct Tuina Sci. 2011;9(6):384-7.

24. Suen LK, Wong EM. Longitudinal changes in the disability level of the elders with low back pain after auriculotherapy. Complement Ther Med. 2008;16(1):28-35.

25. Suen LK, Wong TK, Chung JW, Yip VY. Auriculotherapy on low back pain in the elderly. Complement Ther Clin Pract. 2007;13(1):63-9.
- 2626. Sator-Katzenschlager SM, Scharbert G, Kozek-Langenecker SA, Szeles JC, Finster G, Schiesser AW, et al. The short- and long-term benefit in chronic low back pain through adjuvant electrical versus manual auricular acupuncture. Anesth Analg. 2004;98(5):1359-64. , 2929. Sator-Katzenschlager SM, Szeles JC, Scharbert G, Michalek-Sauberer A, Kober A, Heinze G, Kozek-Langenecker SA. Electrical stimulation of auricular acupuncture points is more effective than conventional manual auricular acupuncture in chronic cervical pain: a pilot study. Anesth Analg. 2003;97(5):1469-73. , 3131. Vas J, Modesto M, Aguilar I, Gonçalo CS, Rivas-Ruiz F. Eficacia y seguridad de la auriculopresión en pacientes de atención primaria con raquialgia crónica no específica: estudio multicéntrico controlado aleatorizado. Rev Int Acupuntura. 2014;8(3):77-86. In the remaining 20% (n=3)2727. Silva AC, Biasotto-Gonzalez DA, Santos DM, Melo NC, Gomes CA, Amorim CF, et al. Evaluation of the immediate effect of auricular acupuncture on pain and electromyographic activity of the upper trapezius muscle in patients with nonspecific neck pain: a randomized, single-blinded, sham-controlled, crossover study. Evid Based Complement Alternat Med [Internet]. 2015 [cited 2018 May 18];2015:1-8. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4588355/
https://www.ncbi.nlm.nih.gov/pmc/article...
, 2828. Ceccherelli F, Tortora P, Nassimbeni C, Casale R, Gagliardi G, Giron G. The therapeutic efficacy of somatic acupuncture is not increased by auriculotherapy: a randomised, blind control study in cervical myofascial pain. Complement Ther Med. 2006;14(1):47-52. , 3030. Eberhardt TD, Hofstätter LM, Lopes SMS, Silva EAA, Ceranto DCFB, Nicola AL. Analgesic comparison of Zen Shiatsu and auricular acupuncture in back pain among nursing professionals. Rev Enferm UERJ [Internet]. 2015 [cited 2018 May 18]; 23(3):324-30. Available from: http://www.e-publicacoes.uerj.br/index.php/enfermagemuerj/article/view/9616/18295
http://www.e-publicacoes.uerj.br/index.p...
, the effects of the interventions in the experimental and control groups were similar.

Seven RCT, which reported pain intensity scores at the end of the treatment period through the VAS2020. Marignan M. Auriculotherapy treatment protocol for low-back pain: a randomized trial. Med Acupunct. 2014;26(3):154-60. , 2323. Zhangxiu X, Limin Y, Yan Z, Liuyan S, Changyu M, Shangjie C, et al. Effect of auricular point sticking on pain due to lumbar strain. J Acupunct Tuina Sci. 2011;9(6):384-7. , 2828. Ceccherelli F, Tortora P, Nassimbeni C, Casale R, Gagliardi G, Giron G. The therapeutic efficacy of somatic acupuncture is not increased by auriculotherapy: a randomised, blind control study in cervical myofascial pain. Complement Ther Med. 2006;14(1):47-52. , the Brief Pain Inventory1818. Yeh CH, Kwai-Ping Suen L, Chien LC, Margolis L, Liang Z, Glick RM, et al. Day-to-day changes of auricular point acupressure to manage chronic low back pain: a 29-day randomized controlled study. Pain Med. 2015;16(10):1857-69. - 1919. Yeh CH, Morone NE, Chien LC, Cao Y, Lu H, Shen J, et al. Auricular point acupressure to manage chronic low back pain in older adults: a randomizedcontrolled pilot study. Evid Based Complement Alternat Med [Internet]. 2014 [cited 2018 May 13];2014:1-11. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4134789/
https://www.ncbi.nlm.nih.gov/pmc/article...
, 2121. Yeh CH, Chien LC, Balaban D, Sponberg R, Primavera J, Morone NE, et al. A randomized clinical trial of auricular point acupressure for chronic low back pain: a feasibility study. Evid Based Complement Alternat Med [Internet]. 2013 [cited 2018 May 17];2013:1-9. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3603381/
https://www.ncbi.nlm.nih.gov/pmc/article...
, or the Pain Intensity Verbal Rating Scale2525. Suen LK, Wong TK, Chung JW, Yip VY. Auriculotherapy on low back pain in the elderly. Complement Ther Clin Pract. 2007;13(1):63-9. , were added to the metanalysis. The remaining studies1717. Ushinohama A, Cunha BP, Costa LO, Barela AM, Freitas PB. Effect of a single session of ear acupuncture on pain intensity and postural control in individuals with chronic low back pain: a randomized controlled trial. Braz J Phys Ther. 2016;20(4):328-35. , 2020. Marignan M. Auriculotherapy treatment protocol for low-back pain: a randomized trial. Med Acupunct. 2014;26(3):154-60. , 2222. Hunter RF, McDonough SM, Bradbury I, Liddle SD, Walsh DM, Dhamija S, et al. Exercise and auricular acupuncture for chronic low-back pain: a feasibility randomized-controlled trial. Clin J Pain. 2012;28(3):259-67. , 2424. Suen LK, Wong EM. Longitudinal changes in the disability level of the elders with low back pain after auriculotherapy. Complement Ther Med. 2008;16(1):28-35. , 2626. Sator-Katzenschlager SM, Scharbert G, Kozek-Langenecker SA, Szeles JC, Finster G, Schiesser AW, et al. The short- and long-term benefit in chronic low back pain through adjuvant electrical versus manual auricular acupuncture. Anesth Analg. 2004;98(5):1359-64. , 2929. Sator-Katzenschlager SM, Szeles JC, Scharbert G, Michalek-Sauberer A, Kober A, Heinze G, Kozek-Langenecker SA. Electrical stimulation of auricular acupuncture points is more effective than conventional manual auricular acupuncture in chronic cervical pain: a pilot study. Anesth Analg. 2003;97(5):1469-73. - 3030. Eberhardt TD, Hofstätter LM, Lopes SMS, Silva EAA, Ceranto DCFB, Nicola AL. Analgesic comparison of Zen Shiatsu and auricular acupuncture in back pain among nursing professionals. Rev Enferm UERJ [Internet]. 2015 [cited 2018 May 18]; 23(3):324-30. Available from: http://www.e-publicacoes.uerj.br/index.php/enfermagemuerj/article/view/9616/18295
http://www.e-publicacoes.uerj.br/index.p...
did not provide sufficient data for this analysis.

The results showed that AA was more effective in reducing pain intensity scores (absolute difference between means: -0.56, [95% confidence interval: -1.09 to -0.03]; p = 0.038), with high heterogeneity I22. Vos T, Barber RN, Bell B, Bertozzi-Villa A, Biryukov S, Bolliger I, et al. Global, regional, and national incidence, prevalence, and years lived with disability for 301 acute and chronic diseases and injuries in 188 countries, 1990–2013: a systematic analysis for the Global Burden of Disease Study 2013. Lancet. 2015;386(9995):743-800. = 86.8%, p < 0.001) ( Figure 2 ). Thus, pain intensity in patients submitted to AA is, on average, 0.560 lower in a scale from 0 to 10, than the pain intensity in the control group. Indeed, the metanalysis average effect, represented by the center of the diamond, is at the left of the vertical center line, indicating that the intervention reduces the probability of the outcome.

Figure 2
– Forest plot of the pain intensity score – Belo Horizonte, MG, Brazil, 2018.

DISCUSSION

The current study proved the benefits of AA for chronic back pain in adults in several pain assessment parameters, whether subjective or physiological, in most of the evaluated RCT. Therefore, the synthesis of the best scientific evidence on the subject may contribute to the implementation of the intervention in clinical practice.

Regarding the methodological quality of the studies, only three2121. Yeh CH, Chien LC, Balaban D, Sponberg R, Primavera J, Morone NE, et al. A randomized clinical trial of auricular point acupressure for chronic low back pain: a feasibility study. Evid Based Complement Alternat Med [Internet]. 2013 [cited 2018 May 17];2013:1-9. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3603381/
https://www.ncbi.nlm.nih.gov/pmc/article...

22. Hunter RF, McDonough SM, Bradbury I, Liddle SD, Walsh DM, Dhamija S, et al. Exercise and auricular acupuncture for chronic low-back pain: a feasibility randomized-controlled trial. Clin J Pain. 2012;28(3):259-67.

23. Zhangxiu X, Limin Y, Yan Z, Liuyan S, Changyu M, Shangjie C, et al. Effect of auricular point sticking on pain due to lumbar strain. J Acupunct Tuina Sci. 2011;9(6):384-7.

24. Suen LK, Wong EM. Longitudinal changes in the disability level of the elders with low back pain after auriculotherapy. Complement Ther Med. 2008;16(1):28-35.
- 2525. Suen LK, Wong TK, Chung JW, Yip VY. Auriculotherapy on low back pain in the elderly. Complement Ther Clin Pract. 2007;13(1):63-9. did not achieve a satisfactory score (higher than three) in the Jadad scale1414. Jadad AR, Moore RA, Carroll D, Jenkinson C, Reynolds DJ, Gavaghan DJ, et al. Assessing the quality of reports of randomized clinical trials: is blinding necessary?. Control Clin Trials. 1996;17(1):1-12. , due to lack of information for the measurement2323. Zhangxiu X, Limin Y, Yan Z, Liuyan S, Changyu M, Shangjie C, et al. Effect of auricular point sticking on pain due to lumbar strain. J Acupunct Tuina Sci. 2011;9(6):384-7. or mismatches in the randomization and masking processes2424. Suen LK, Wong EM. Longitudinal changes in the disability level of the elders with low back pain after auriculotherapy. Complement Ther Med. 2008;16(1):28-35. - 2525. Suen LK, Wong TK, Chung JW, Yip VY. Auriculotherapy on low back pain in the elderly. Complement Ther Clin Pract. 2007;13(1):63-9. . These are key prerequisites for the good quality of the RCT, since they are universally considered gold standard accepted for evidence-based practice and, if properly conducted, its use is recommended for clinical and policy decision-making on health priorities3333. Hansson SO. Why and for what are clinical trials the gold standard? Scand J Public Health. 2014;42(13 Suppl):41-8. .

In acupuncture clinical trials, the ideal control group has not yet been determined3434. Moffet HH. Sham acupuncture may be as efficacious as true acupuncture: a systematic review of clinical trials. J Altern Complement Med. 2009;15(3):213-6. ; however, the comparison with this group, whether with gold standard therapy or no procedure at all, is the best way to verify the real effects of the intervention. In fact, some studies have applied2222. Hunter RF, McDonough SM, Bradbury I, Liddle SD, Walsh DM, Dhamija S, et al. Exercise and auricular acupuncture for chronic low-back pain: a feasibility randomized-controlled trial. Clin J Pain. 2012;28(3):259-67.

23. Zhangxiu X, Limin Y, Yan Z, Liuyan S, Changyu M, Shangjie C, et al. Effect of auricular point sticking on pain due to lumbar strain. J Acupunct Tuina Sci. 2011;9(6):384-7.

24. Suen LK, Wong EM. Longitudinal changes in the disability level of the elders with low back pain after auriculotherapy. Complement Ther Med. 2008;16(1):28-35.

25. Suen LK, Wong TK, Chung JW, Yip VY. Auriculotherapy on low back pain in the elderly. Complement Ther Clin Pract. 2007;13(1):63-9.
- 2626. Sator-Katzenschlager SM, Scharbert G, Kozek-Langenecker SA, Szeles JC, Finster G, Schiesser AW, et al. The short- and long-term benefit in chronic low back pain through adjuvant electrical versus manual auricular acupuncture. Anesth Analg. 2004;98(5):1359-64. , 2828. Ceccherelli F, Tortora P, Nassimbeni C, Casale R, Gagliardi G, Giron G. The therapeutic efficacy of somatic acupuncture is not increased by auriculotherapy: a randomised, blind control study in cervical myofascial pain. Complement Ther Med. 2006;14(1):47-52.

29. Sator-Katzenschlager SM, Szeles JC, Scharbert G, Michalek-Sauberer A, Kober A, Heinze G, Kozek-Langenecker SA. Electrical stimulation of auricular acupuncture points is more effective than conventional manual auricular acupuncture in chronic cervical pain: a pilot study. Anesth Analg. 2003;97(5):1469-73.
- 3030. Eberhardt TD, Hofstätter LM, Lopes SMS, Silva EAA, Ceranto DCFB, Nicola AL. Analgesic comparison of Zen Shiatsu and auricular acupuncture in back pain among nursing professionals. Rev Enferm UERJ [Internet]. 2015 [cited 2018 May 18]; 23(3):324-30. Available from: http://www.e-publicacoes.uerj.br/index.php/enfermagemuerj/article/view/9616/18295
http://www.e-publicacoes.uerj.br/index.p...
active treatment in the control group, which is justifiable when the best treatment for the clinical condition has already been determined. Other studies1818. Yeh CH, Kwai-Ping Suen L, Chien LC, Margolis L, Liang Z, Glick RM, et al. Day-to-day changes of auricular point acupressure to manage chronic low back pain: a 29-day randomized controlled study. Pain Med. 2015;16(10):1857-69.

19. Yeh CH, Morone NE, Chien LC, Cao Y, Lu H, Shen J, et al. Auricular point acupressure to manage chronic low back pain in older adults: a randomizedcontrolled pilot study. Evid Based Complement Alternat Med [Internet]. 2014 [cited 2018 May 13];2014:1-11. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4134789/
https://www.ncbi.nlm.nih.gov/pmc/article...

20. Marignan M. Auriculotherapy treatment protocol for low-back pain: a randomized trial. Med Acupunct. 2014;26(3):154-60.
- 2121. Yeh CH, Chien LC, Balaban D, Sponberg R, Primavera J, Morone NE, et al. A randomized clinical trial of auricular point acupressure for chronic low back pain: a feasibility study. Evid Based Complement Alternat Med [Internet]. 2013 [cited 2018 May 17];2013:1-9. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3603381/
https://www.ncbi.nlm.nih.gov/pmc/article...
, 2727. Silva AC, Biasotto-Gonzalez DA, Santos DM, Melo NC, Gomes CA, Amorim CF, et al. Evaluation of the immediate effect of auricular acupuncture on pain and electromyographic activity of the upper trapezius muscle in patients with nonspecific neck pain: a randomized, single-blinded, sham-controlled, crossover study. Evid Based Complement Alternat Med [Internet]. 2015 [cited 2018 May 18];2015:1-8. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4588355/
https://www.ncbi.nlm.nih.gov/pmc/article...
applied auricular acupuncture in points that were not related to the phenomenon being studied, an acupuncture technique called sham (placebo, fake, or simulated). This technique violates traditional acupuncture theories on location or indications of the acupoints and, therefore, it is unable to achieve the results intended by real acupuncture3434. Moffet HH. Sham acupuncture may be as efficacious as true acupuncture: a systematic review of clinical trials. J Altern Complement Med. 2009;15(3):213-6. . Finally, two other studies1717. Ushinohama A, Cunha BP, Costa LO, Barela AM, Freitas PB. Effect of a single session of ear acupuncture on pain intensity and postural control in individuals with chronic low back pain: a randomized controlled trial. Braz J Phys Ther. 2016;20(4):328-35. , 3131. Vas J, Modesto M, Aguilar I, Gonçalo CS, Rivas-Ruiz F. Eficacia y seguridad de la auriculopresión en pacientes de atención primaria con raquialgia crónica no específica: estudio multicéntrico controlado aleatorizado. Rev Int Acupuntura. 2014;8(3):77-86. applied inactive treatments in the control group with the intention of checking whether the expectations of the patient related to the therapy could have an impact on the treatment3535. Medoff ZM, Colloca L. Placebo analgesia: understanding the mechanisms. Pain Manag [Internet]. 2015 [cited 2018 May 18];5:89-96. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4388042/
https://www.ncbi.nlm.nih.gov/pmc/article...
.

Regarding the evaluated outcomes, it is important to investigate, besides pain intensity, other intervention actions on the chronic algic process, as it was carried out in all included RCT. A comprehensive pain assessment is essential to identify, besides the intensity, social, biological, cultural, and psychological factors that have an impact on it, as well as the negative impact that this experience can cause in the lives of those who were affected3636. Moura CC, Chaves ECL, Souza VHS, Iunes DH, Ribeiro CRG, Paraízo CMS, et al. Impactos da dor crônica na vida das pessoas e a assistência de enfermagem no processo Av Enferm [Internet]. 2017 [citado 2018 maio 18];35(1):53-62. Disponível em: http://www.scielo.org.co/pdf/aven/v35n1/v35n1a06.pdf
http://www.scielo.org.co/pdf/aven/v35n1/...
. In fact, auricular acupuncture may alter other phenomena related to chronic pain, such as the psychological well-being, level of activity, quality of sleep, amount of consumed medication, and even facilitate the return to work activities2626. Sator-Katzenschlager SM, Scharbert G, Kozek-Langenecker SA, Szeles JC, Finster G, Schiesser AW, et al. The short- and long-term benefit in chronic low back pain through adjuvant electrical versus manual auricular acupuncture. Anesth Analg. 2004;98(5):1359-64. , thus highlighting the importance of investigating such outcomes. In addition, physiological parameters are important indicators capable to provide a broad assessment of the health status of individuals who suffer from pain and the changes that take place over time3737. Vet HC, Terwee CB, Ostelo RW, Beckerman H, Knol DL, Bouter LX. Minimal changes in health status questionnaires: distinction between minimally detectable change and minimally important change. Health Qual Life Outcomes [Internet]. 2006 [cited 2018 May 18];4(54):1-5. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1560110/
https://www.ncbi.nlm.nih.gov/pmc/article...
, thus allowing the analysis of the response to treatment3838. Herndon CM, Zoberi KS, Gardner BJ. Common questions about chronic low back pain. Am Fam Physician. 2015;91(10):708-14. .

Through the systematic analysis of the included RCT, it was possible to confirm that there was no standardization in the AA protocol for chronic back pain, in relation to the number of sessions, treatment time, application device, time the device was kept on, type of stimulation, and points of application.

Nonetheless, it was noted that most of the studies1818. Yeh CH, Kwai-Ping Suen L, Chien LC, Margolis L, Liang Z, Glick RM, et al. Day-to-day changes of auricular point acupressure to manage chronic low back pain: a 29-day randomized controlled study. Pain Med. 2015;16(10):1857-69. - 1919. Yeh CH, Morone NE, Chien LC, Cao Y, Lu H, Shen J, et al. Auricular point acupressure to manage chronic low back pain in older adults: a randomizedcontrolled pilot study. Evid Based Complement Alternat Med [Internet]. 2014 [cited 2018 May 13];2014:1-11. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4134789/
https://www.ncbi.nlm.nih.gov/pmc/article...
, 2121. Yeh CH, Chien LC, Balaban D, Sponberg R, Primavera J, Morone NE, et al. A randomized clinical trial of auricular point acupressure for chronic low back pain: a feasibility study. Evid Based Complement Alternat Med [Internet]. 2013 [cited 2018 May 17];2013:1-9. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3603381/
https://www.ncbi.nlm.nih.gov/pmc/article...
, 2323. Zhangxiu X, Limin Y, Yan Z, Liuyan S, Changyu M, Shangjie C, et al. Effect of auricular point sticking on pain due to lumbar strain. J Acupunct Tuina Sci. 2011;9(6):384-7.

24. Suen LK, Wong EM. Longitudinal changes in the disability level of the elders with low back pain after auriculotherapy. Complement Ther Med. 2008;16(1):28-35.
- 2525. Suen LK, Wong TK, Chung JW, Yip VY. Auriculotherapy on low back pain in the elderly. Complement Ther Clin Pract. 2007;13(1):63-9. , 3131. Vas J, Modesto M, Aguilar I, Gonçalo CS, Rivas-Ruiz F. Eficacia y seguridad de la auriculopresión en pacientes de atención primaria con raquialgia crónica no específica: estudio multicéntrico controlado aleatorizado. Rev Int Acupuntura. 2014;8(3):77-86. opted for the Chinese treatment approach. The treatment principles in Traditional Chinese Medicine (TCM) are based on the belief that the ear is related to all body parts and internal organs, and as the auricular acupoints are stimulated, the meridians may be activated2424. Suen LK, Wong EM. Longitudinal changes in the disability level of the elders with low back pain after auriculotherapy. Complement Ther Med. 2008;16(1):28-35. , which are passages for the flow of “qi” and “blood”. These two body fluids are relevant in the TCM, and spread to the entire body surface, connecting the inter to the outer body3939. Wang GJ, Ayati MH, Zhang WB. Meridian studies in China: a systematic review. J Acupunct Meridian Stud. 2010;3(1):1-9. .

The number of AA sessions for chronic back pain is approximately five (variation from one to eight – average of 4.57 sessions), and the treatment time is from 20 minutes to 8 weeks (average of 3.93 weeks) with a weekly application of seeds or auricular needles, and the mean time the devices are kept on the ear is 4 days with a maximum period of 7 days.

Regarding the application devices, a study with the objective of analyzing the efficacy of auriculotherapy with needles and seeds in stressed professionals identified better results with the application of needles4040. Kurebayashi LFS, Gnatta JR, Borges TP, Belisse G, Coca S, Minami A, et al. The applicability of auriculotherapy with needles or seeds to reduce stress in nursing professionals. Rev Esc Enferm USP [Internet]. 2012 [cited 2018 May 18];46(1):89-95. Available from: http://www.scielo.br/pdf/reeusp/v46n1/en_v46n1a12.pdf
http://www.scielo.br/pdf/reeusp/v46n1/en...
. However, the use of this device can be uncomfortable during application and permanence, thus evidencing the disadvantage of needles in relation to seeds4040. Kurebayashi LFS, Gnatta JR, Borges TP, Belisse G, Coca S, Minami A, et al. The applicability of auriculotherapy with needles or seeds to reduce stress in nursing professionals. Rev Esc Enferm USP [Internet]. 2012 [cited 2018 May 18];46(1):89-95. Available from: http://www.scielo.br/pdf/reeusp/v46n1/en_v46n1a12.pdf
http://www.scielo.br/pdf/reeusp/v46n1/en...
. In the case of using seeds, patient participation is necessary, that is, the effect caused by the application of seeds is proportional to the manual stimulation exerted upon it; therefore, if the patient forgets to press it, it will not have any effect, which could be considered a limiting factor, besides representing a source of bias to the research1313. Moura CC, Carvalho CC, Silva AM, Iunes DH, Carvalho EC, Chaves ECL. Auriculoterapia efeito sobre a ansiedade. Rev Cuba Enf [Internet]. 2014 [citado 2018 maio 18];30(2):1-15. Disponible en: http://www.medigraphic.com/pdfs/revcubenf/cnf-2014/cnf142e.pdf
http://www.medigraphic.com/pdfs/revcuben...
.

In relation to the stimulation exerted on the device, manual stimulation is indispensable for the cases using seeds1313. Moura CC, Carvalho CC, Silva AM, Iunes DH, Carvalho EC, Chaves ECL. Auriculoterapia efeito sobre a ansiedade. Rev Cuba Enf [Internet]. 2014 [citado 2018 maio 18];30(2):1-15. Disponible en: http://www.medigraphic.com/pdfs/revcubenf/cnf-2014/cnf142e.pdf
http://www.medigraphic.com/pdfs/revcuben...
, and for the cases in which auricular needles were adopted, whether manual or electric2020. Marignan M. Auriculotherapy treatment protocol for low-back pain: a randomized trial. Med Acupunct. 2014;26(3):154-60. , 4040. Kurebayashi LFS, Gnatta JR, Borges TP, Belisse G, Coca S, Minami A, et al. The applicability of auriculotherapy with needles or seeds to reduce stress in nursing professionals. Rev Esc Enferm USP [Internet]. 2012 [cited 2018 May 18];46(1):89-95. Available from: http://www.scielo.br/pdf/reeusp/v46n1/en_v46n1a12.pdf
http://www.scielo.br/pdf/reeusp/v46n1/en...
. In addition, auricular acupuncture performed with electric stimulation may lead to faster pain relief after some minutes of stimulation2020. Marignan M. Auriculotherapy treatment protocol for low-back pain: a randomized trial. Med Acupunct. 2014;26(3):154-60. , which demonstrate that the association of this intervention with electric current ensures even more positive results reducing pain intensity, especially in the cases of severe pain. However, it is worth noting the need for further research.

Regarding the applied auricular acupoints, the most common were Shenmen (central nervous system), kidney, sympathetic (sympathetic nervous system or neurovegetative system), subcortex, liver, bladder, points at the pain site (cervical, thoracic, and/or lumbar), on a unilateral basis. The painkiller or pain relief point, which is also indicated for this clinical condition, was used in only two studies1313. Moura CC, Carvalho CC, Silva AM, Iunes DH, Carvalho EC, Chaves ECL. Auriculoterapia efeito sobre a ansiedade. Rev Cuba Enf [Internet]. 2014 [citado 2018 maio 18];30(2):1-15. Disponible en: http://www.medigraphic.com/pdfs/revcubenf/cnf-2014/cnf142e.pdf
http://www.medigraphic.com/pdfs/revcuben...
, 2626. Sator-Katzenschlager SM, Scharbert G, Kozek-Langenecker SA, Szeles JC, Finster G, Schiesser AW, et al. The short- and long-term benefit in chronic low back pain through adjuvant electrical versus manual auricular acupuncture. Anesth Analg. 2004;98(5):1359-64. . However, this point does not appear in the World Federation of Acupuncture-Moxibustion Societies4141. World Federation of Acupuncture-Moxibustion Societies (WFAS). Auricular Acupuncture Point (WFAS STANDARD-002:2012). World J Acupunct Moxibustion. 2013;23(3):12-21. map with this nomenclature; therefore, a validation process is recommended for the location of this point before safely using it.

The use of an electric detector of acupoints for tracking the auricular points is recommended. The trackers detect the electric resistance of the points that2525. Suen LK, Wong TK, Chung JW, Yip VY. Auriculotherapy on low back pain in the elderly. Complement Ther Clin Pract. 2007;13(1):63-9. , under pathological conditions, are lower than the normal conditions. It is also important to point out that to obtain better precision locating the auricular points, they should be related to patient complains. In addition, the likely point location must be guided by an auricular map, since the distribution of the points follows the configuration of an upside-down fetus in these maps77. Gori L, Firenzuoli F. Ear acupuncture in European traditional medicine. Evid Based Complement Alternat Med [Internet]. 2007 [cited 2018 May 17];4 Suppl 1:13-6. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2206232/
https://www.ncbi.nlm.nih.gov/pmc/article...
, as some studies have shown1818. Yeh CH, Kwai-Ping Suen L, Chien LC, Margolis L, Liang Z, Glick RM, et al. Day-to-day changes of auricular point acupressure to manage chronic low back pain: a 29-day randomized controlled study. Pain Med. 2015;16(10):1857-69. , 2525. Suen LK, Wong TK, Chung JW, Yip VY. Auriculotherapy on low back pain in the elderly. Complement Ther Clin Pract. 2007;13(1):63-9. , 3030. Eberhardt TD, Hofstätter LM, Lopes SMS, Silva EAA, Ceranto DCFB, Nicola AL. Analgesic comparison of Zen Shiatsu and auricular acupuncture in back pain among nursing professionals. Rev Enferm UERJ [Internet]. 2015 [cited 2018 May 18]; 23(3):324-30. Available from: http://www.e-publicacoes.uerj.br/index.php/enfermagemuerj/article/view/9616/18295
http://www.e-publicacoes.uerj.br/index.p...
- 3131. Vas J, Modesto M, Aguilar I, Gonçalo CS, Rivas-Ruiz F. Eficacia y seguridad de la auriculopresión en pacientes de atención primaria con raquialgia crónica no específica: estudio multicéntrico controlado aleatorizado. Rev Int Acupuntura. 2014;8(3):77-86. .

Only one study3131. Vas J, Modesto M, Aguilar I, Gonçalo CS, Rivas-Ruiz F. Eficacia y seguridad de la auriculopresión en pacientes de atención primaria con raquialgia crónica no específica: estudio multicéntrico controlado aleatorizado. Rev Int Acupuntura. 2014;8(3):77-86. carried out the intervention in an individualized format. Such an approach is positive, since it takes into consideration the reestablishment of the energy balance of the body as a whole, promoting a faster recovery of the health status. When auricular acupuncture is strictly based on the TCM principles, variations in the auricular points, number of sessions and application devices may be justified. According to such principles, treatment customization is important, since each individual is unique, and the imbalance patterns may affect each person differently4040. Kurebayashi LFS, Gnatta JR, Borges TP, Belisse G, Coca S, Minami A, et al. The applicability of auriculotherapy with needles or seeds to reduce stress in nursing professionals. Rev Esc Enferm USP [Internet]. 2012 [cited 2018 May 18];46(1):89-95. Available from: http://www.scielo.br/pdf/reeusp/v46n1/en_v46n1a12.pdf
http://www.scielo.br/pdf/reeusp/v46n1/en...
.

In fact, researchers4242. Kurebayashi LFS, Silva MJP. Chinese auriculotherapy to improve quality of life of nursing team. Rev Bras Enferm [Internet]. 2015 [cited 2018 May 10];68(1):109-15. Available from: http://www.scielo.br/pdf/reben/v68n1/en_0034-7167-reben-68-01-0117.pdf
http://www.scielo.br/pdf/reben/v68n1/en_...
have pointed out that, to assess the efficacy of the intervention applied with a protocol of points, as required by scientific research, and without a protocol, as guided by the TCM, the best results are obtained in the group without a protocol, demonstrating that auriculotherapy carried out individually, with an aim at the energy balance of the individual, is capable of improving the range of the therapy.

However, the establishment of fixed protocols favors its replicability and further implementation in clinical practice. It is important to point out that, to determine the best forms for treating patients, it is first necessary to demonstrate scientifically the efficacy of the intervention, and then to apply this evidence into practice. This takes place through replicability of the studies and, for such scope, it becomes crucial to establish consistent methodological protocols, as recommended by STRICTA3232. MacPherson H, Altman DG, Hammerschlag R, Youping L, Taixiang W, White A, et al. Revised Standards for Reporting Interventions in Clinical Trials of Acupuncture (STRICTA): extending the CONSORT statement. PLoS Med [Internet]. 2010 [cited 2018 May 18];7(6):1-11. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2882429/
https://www.ncbi.nlm.nih.gov/pmc/article...
.

Acupuncture RCT intervention reports recommend the description of the participating acupuncturists, with qualifications or professional affiliation, years of expertise, among other information3232. MacPherson H, Altman DG, Hammerschlag R, Youping L, Taixiang W, White A, et al. Revised Standards for Reporting Interventions in Clinical Trials of Acupuncture (STRICTA): extending the CONSORT statement. PLoS Med [Internet]. 2010 [cited 2018 May 18];7(6):1-11. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2882429/
https://www.ncbi.nlm.nih.gov/pmc/article...
. Most of the included RCT1717. Ushinohama A, Cunha BP, Costa LO, Barela AM, Freitas PB. Effect of a single session of ear acupuncture on pain intensity and postural control in individuals with chronic low back pain: a randomized controlled trial. Braz J Phys Ther. 2016;20(4):328-35. , 1818. Yeh CH, Kwai-Ping Suen L, Chien LC, Margolis L, Liang Z, Glick RM, et al. Day-to-day changes of auricular point acupressure to manage chronic low back pain: a 29-day randomized controlled study. Pain Med. 2015;16(10):1857-69. - 1919. Yeh CH, Morone NE, Chien LC, Cao Y, Lu H, Shen J, et al. Auricular point acupressure to manage chronic low back pain in older adults: a randomizedcontrolled pilot study. Evid Based Complement Alternat Med [Internet]. 2014 [cited 2018 May 13];2014:1-11. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4134789/
https://www.ncbi.nlm.nih.gov/pmc/article...
, 2121. Yeh CH, Chien LC, Balaban D, Sponberg R, Primavera J, Morone NE, et al. A randomized clinical trial of auricular point acupressure for chronic low back pain: a feasibility study. Evid Based Complement Alternat Med [Internet]. 2013 [cited 2018 May 17];2013:1-9. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3603381/
https://www.ncbi.nlm.nih.gov/pmc/article...
- 2222. Hunter RF, McDonough SM, Bradbury I, Liddle SD, Walsh DM, Dhamija S, et al. Exercise and auricular acupuncture for chronic low-back pain: a feasibility randomized-controlled trial. Clin J Pain. 2012;28(3):259-67. , 2727. Silva AC, Biasotto-Gonzalez DA, Santos DM, Melo NC, Gomes CA, Amorim CF, et al. Evaluation of the immediate effect of auricular acupuncture on pain and electromyographic activity of the upper trapezius muscle in patients with nonspecific neck pain: a randomized, single-blinded, sham-controlled, crossover study. Evid Based Complement Alternat Med [Internet]. 2015 [cited 2018 May 18];2015:1-8. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4588355/
https://www.ncbi.nlm.nih.gov/pmc/article...
- 2828. Ceccherelli F, Tortora P, Nassimbeni C, Casale R, Gagliardi G, Giron G. The therapeutic efficacy of somatic acupuncture is not increased by auriculotherapy: a randomised, blind control study in cervical myofascial pain. Complement Ther Med. 2006;14(1):47-52. , 3131. Vas J, Modesto M, Aguilar I, Gonçalo CS, Rivas-Ruiz F. Eficacia y seguridad de la auriculopresión en pacientes de atención primaria con raquialgia crónica no específica: estudio multicéntrico controlado aleatorizado. Rev Int Acupuntura. 2014;8(3):77-86. mentioned the training area of these professionals; however, only two1717. Ushinohama A, Cunha BP, Costa LO, Barela AM, Freitas PB. Effect of a single session of ear acupuncture on pain intensity and postural control in individuals with chronic low back pain: a randomized controlled trial. Braz J Phys Ther. 2016;20(4):328-35. , 2727. Silva AC, Biasotto-Gonzalez DA, Santos DM, Melo NC, Gomes CA, Amorim CF, et al. Evaluation of the immediate effect of auricular acupuncture on pain and electromyographic activity of the upper trapezius muscle in patients with nonspecific neck pain: a randomized, single-blinded, sham-controlled, crossover study. Evid Based Complement Alternat Med [Internet]. 2015 [cited 2018 May 18];2015:1-8. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4588355/
https://www.ncbi.nlm.nih.gov/pmc/article...
provided the length of experience in the area. In fact, professional knowledge, experience related to the application of the technique, and clinical practice are indispensable factors for reaching positive results4343. Kurebayashi LFS, Gnatta JR, Borges TP, Silva MJP. Effectiveness of auriculotherapy for stress, based on experience of the therapist: a clinical trial. Acta Paul Enf [Internet]. 2012 [cited 2018 May 10];25(5):694-700. Available from: http://www.scielo.br/pdf/ape/v25n5/en_08.pdf
http://www.scielo.br/pdf/ape/v25n5/en_08...
.

Finally, it was possible to identify a significant reduction in the pain intensity scores of adults with chronic back pain submitted to AA treatment (p=0.038 value). Therefore, it can be said that, when compared to a control group, this modality presents advantages in relieving pain.

The reduction of pain by AA is explained by some assumptions of pain relief by acupuncture, which include the “gate control theory of pain”4444. Melzack R, Wall PD. Pain mechanisms: a new theory. Science. 1965;150(3699):971-9. ; descending inhibitory control; and patient expectations towards pain relief (pain relief placebo)4545. Chae Y, Olausson H. The role of touch in acupuncture treatment. Acupunct Med. 2017;35(2):148-52.

46. Fleckenstein J. Acupuncture in the context of diffuse noxious inhibitory control. Eur J Pain. 2013;17:141-2.
- 4747. Lin JG, Chen WL. Acupuncture analgesia: a review of its mechanisms of actions. Am J Chin Med. 2008;36(4):635-45. . In addition, the sensory-discriminative and affective-social aspects of the touch play an important role in the therapeutic effect of acupuncture, since there is an involvement of type Aβ myelinated nociceptive fibers providing spatial discriminative information to quickly identify where the stimulus is located in the body, besides the type C unmyelinated tactile fibers, with slow conduction velocities, which are involved in affective-emotional functions4545. Chae Y, Olausson H. The role of touch in acupuncture treatment. Acupunct Med. 2017;35(2):148-52. .

On the other hand, four studies1919. Yeh CH, Morone NE, Chien LC, Cao Y, Lu H, Shen J, et al. Auricular point acupressure to manage chronic low back pain in older adults: a randomizedcontrolled pilot study. Evid Based Complement Alternat Med [Internet]. 2014 [cited 2018 May 13];2014:1-11. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4134789/
https://www.ncbi.nlm.nih.gov/pmc/article...
, 2121. Yeh CH, Chien LC, Balaban D, Sponberg R, Primavera J, Morone NE, et al. A randomized clinical trial of auricular point acupressure for chronic low back pain: a feasibility study. Evid Based Complement Alternat Med [Internet]. 2013 [cited 2018 May 17];2013:1-9. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3603381/
https://www.ncbi.nlm.nih.gov/pmc/article...
, 2323. Zhangxiu X, Limin Y, Yan Z, Liuyan S, Changyu M, Shangjie C, et al. Effect of auricular point sticking on pain due to lumbar strain. J Acupunct Tuina Sci. 2011;9(6):384-7. , 2828. Ceccherelli F, Tortora P, Nassimbeni C, Casale R, Gagliardi G, Giron G. The therapeutic efficacy of somatic acupuncture is not increased by auriculotherapy: a randomised, blind control study in cervical myofascial pain. Complement Ther Med. 2006;14(1):47-52. demonstrated a lack of effect, that is, these investigations did not show statistically significant differences between the groups regarding the benefit or harm caused by the intervention. In fact, two studies1919. Yeh CH, Morone NE, Chien LC, Cao Y, Lu H, Shen J, et al. Auricular point acupressure to manage chronic low back pain in older adults: a randomizedcontrolled pilot study. Evid Based Complement Alternat Med [Internet]. 2014 [cited 2018 May 13];2014:1-11. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4134789/
https://www.ncbi.nlm.nih.gov/pmc/article...
, 2121. Yeh CH, Chien LC, Balaban D, Sponberg R, Primavera J, Morone NE, et al. A randomized clinical trial of auricular point acupressure for chronic low back pain: a feasibility study. Evid Based Complement Alternat Med [Internet]. 2013 [cited 2018 May 17];2013:1-9. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3603381/
https://www.ncbi.nlm.nih.gov/pmc/article...
worked with a very small sample: the first1919. Yeh CH, Morone NE, Chien LC, Cao Y, Lu H, Shen J, et al. Auricular point acupressure to manage chronic low back pain in older adults: a randomizedcontrolled pilot study. Evid Based Complement Alternat Med [Internet]. 2014 [cited 2018 May 13];2014:1-11. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4134789/
https://www.ncbi.nlm.nih.gov/pmc/article...
refers to a pilot study, whereas in the second, a sample calculation to estimate the minimum necessary sample size was not carried out2121. Yeh CH, Chien LC, Balaban D, Sponberg R, Primavera J, Morone NE, et al. A randomized clinical trial of auricular point acupressure for chronic low back pain: a feasibility study. Evid Based Complement Alternat Med [Internet]. 2013 [cited 2018 May 17];2013:1-9. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3603381/
https://www.ncbi.nlm.nih.gov/pmc/article...
. The third study2323. Zhangxiu X, Limin Y, Yan Z, Liuyan S, Changyu M, Shangjie C, et al. Effect of auricular point sticking on pain due to lumbar strain. J Acupunct Tuina Sci. 2011;9(6):384-7. applied an active treatment in both groups (medicated patch), which may have led to considerable progress to the control group in relation to the VAS after 2-week treatment (p<0.01). This fact is believed to be associated with the lack of effect observed during the performance of the metanalysis. Finally, the last investigation2828. Ceccherelli F, Tortora P, Nassimbeni C, Casale R, Gagliardi G, Giron G. The therapeutic efficacy of somatic acupuncture is not increased by auriculotherapy: a randomised, blind control study in cervical myofascial pain. Complement Ther Med. 2006;14(1):47-52. did not find effect superiority of the systemic acupuncture associated with auriculotherapy in relation to the isolated systemic acupuncture, which corresponds to the metanalysis result.

Overall, a substantial variation in auricular acupuncture was observed. These variations, especially in relation to the application device, including differences in the control group, made inviable the development of the subgroup analysis or meta-regression, respectively, due to the small number of studies in each of these specifications. In addition, differences related to the number of sessions, treatment time, time the device was kept on, type of stimulation, application points, location of the points, and experience of the professional who carried out the intervention may have an impact on the clinical effects, which reinforce the need for therapy standardization for this condition.

Another limitation of the current study is that the Chinese database was not consulted, and the articles in Mandarin found in the accessed electronic database were not included in the sample of the current review, since they were not located through bibliographic commutation or through contact with the authors. Further studies must take these databases into consideration, taking into account that China is the cradle of TCM and acupuncture.

CONCLUSION

Auricular acupuncture is an integrative, complementary, and promising health practice for the treatment of back pain, since it considerably reduced pain intensity scores in relation to a control group. However, the high heterogeneity present in the RCT limited the findings.

Nonetheless, a possible protocol may be established for this clinical condition: the application of the technique in 5 weekly sessions, with seeds or semi-permanent needles in the Shenmen points (central nervous system), kidney, sympathetic (sympathetic nervous system or neurovegetative), subcortex, liver, bladder, and points in the pain site (cervical, thoracic, and/or lumbar), unilaterally, changing the ear at each session, and mean time of 4 days with the devices kept on, with a maximum of 7 days. In addition, the use of an electric detector of acupoints is recommended to guide directions to the site, based on patient complains, and use of an auricular map. The most common outcomes to assess this clinical condition were pain intensity, medication consumption, physical disability, quality of pain, and quality of life.

This protocol needs validation by further studies, including the exact site of the point called pain relief, in order to verify whether it matches the subcortex points.

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  • Financial support This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) - Finance Code 001. Fundação de Amparo à Pesquisa do Estado de Minas Gerais . APQ-01681-18.

Publication Dates

  • Publication in this collection
    19 Aug 2019
  • Date of issue
    2019

History

  • Received
    27 May 2018
  • Accepted
    25 Sept 2018
Universidade de São Paulo, Escola de Enfermagem Av. Dr. Enéas de Carvalho Aguiar, 419 , 05403-000 São Paulo - SP/ Brasil, Tel./Fax: (55 11) 3061-7553, - São Paulo - SP - Brazil
E-mail: reeusp@usp.br