Brief Article
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World J Gastroenterol. Jan 21, 2013; 19(3): 381-388
Published online Jan 21, 2013. doi: 10.3748/wjg.v19.i3.381
Acupuncture transcutaneous electrical nerve stimulation reduces discomfort associated with barostat-induced rectal distension: A randomized-controlled study
Wing-Wa Leung, Alice YM Jones, Simon SM Ng, Cherry YN Wong, Janet FY Lee
Wing-Wa Leung, Alice YM Jones, Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hung Hom, Hong Kong 999077, China
Alice YM Jones, Faculty of Health Sciences, The University of Sydney, Sydney, NSW 2006, Australia
Simon SM Ng, Cherry YN Wong, Janet FY Lee, Division of Colorectal Surgery, Department of Surgery, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong 999077, China
Author contributions: Leung WW, Jones AYM and Ng SSM designed research; Leung WW contributed to sample recruitment and explanation of procedures to subjects; Wong CYN contributed to data collection and analytic procedure in laboratory; Lee JFY analyzed data; and Leung WW, Jones AYM and Ng SSM wrote the paper.
Correspondence to: Wing-Wa Leung, MSc, PT, Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hung Hom, Hong Kong 999077, China. leungww@surgery.cuhk.edu.hk
Telephone: +852-26321495 Fax: +852-26377974
Received: May 29, 2012
Revised: September 5, 2012
Accepted: September 22, 2012
Published online: January 21, 2013
Abstract

AIM: To explore the effectiveness of acupuncture transcutaneous electrical nerve stimulation (Acu-TENS), a non-invasive modality in reduction of rectal discomfort during barostat-induced rectal distension.

METHODS: Forty healthy subjects were randomized to receive 45 min of either Acu-TENS or placebo-TENS (no electrical output) over acupuncture points Hegu (large-intestine 4), Neiguan (pericardium 6) and Zusanli (stomach 36). A balloon catheter attached to a dual-drive barostat machine was then inserted into the subjects’ rectum. A step-wise (4 mmHg) increase in balloon pressure was induced until maximal tolerable or 48 mmHg. Visual analogue scale and a 5-point subjective discomfort scale (no perception, first perception of distension, urge to defecate, discomfort/pain and extreme pain) were used to assess rectal discomfort at each distension pressure. Blood beta-endorphin levels were measured before, immediately after intervention, at 24 mmHg and at maximal tolerable distension pressure.

RESULTS: There was no difference in the demographic data and baseline plasma beta-endorphin levels between the two groups. Perception threshold levels were higher in the Acu-TENS group when compared to the placebo group, but the difference reached statistical significance only at the sensations “urge to defecate” and “pain”. The distension pressures recorded at the “urge to defecate” sensation for the Acu-TENS and placebo-TENS groups were 28.0 ± 4.5 mmHg and 24.6 ± 5.7 mmHg, respectively (P = 0.043); and the pressures recorded for the “pain” sensation for these two groups were 36.0 ± 4.2 mmHg and 30.5 ± 4.3 mmHg respectively (P = 0.002). Compared to the placebo group, a higher number of participants in the Acu-TENS group tolerated higher distension pressures (> 40 mmHg) (65% in Acu-TENS vs 25% in placebo, P = 0.02). The plasma beta-endorphin levels of the Acu-TENS group were significantly higher than that of the placebo group at barostat inflation pressure of 24 mmHg (1.31 ± 0.40 ng/mL vs 1.04 ± 0.43 ng/mL, P = 0.044) and at maximal inflation pressure (1.46 ± 0.53 ng/mL vs 0.95 ± 0.38 ng/mL, P = 0.003).

CONCLUSION: Acu-TENS reduced rectal discomfort during barostat-induced rectal distension and concurrently associated with a rise in beta-endorphin level.

Keywords: Colonoscopy, Rectal discomfort, Transcutaneous electrical nerve stimulation, Acupuncture, Visceral pain