Effect of acupuncture at Baliao (BL31, BL32, BL33, BL34) on complete spontaneous bowel movements in functional constipation patients: study protocol for a randomized sham-controlled trial

Effect of acupuncture at Baliao (BL31, BL32, BL33, BL34) on complete spontaneous bowel movements in functional constipation patients: study protocol for a randomized sham-controlled trial | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Study protocol Effect of acupuncture at Baliao (BL31, BL32, BL33, BL34) on complete spontaneous bowel movements in functional constipation patients: study protocol for a randomized sham-controlled trial Chen Wei, Muwen Qu This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7351160/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 4 You are reading this latest preprint version Abstract Background Functional constipation lacks satisfactory and curative therapy. Acupuncture is a promising treatment while high-quality evidence is insufficient. Method This is a multicenter, single-blind, superiority, parallel, randomized controlled trial. Participants diagnosed with functional constipation are allocated to treatment (Baliao acupuncture group) and control (sham-acupuncture group) groups at a 1:1 ratio. The randomization sequence is computer-generated. The primary outcome is the change from baseline in complete spontaneous bowel movements per week with a superiority margin of 1.5 to compare the Baliao acupuncture group and sham-acupuncture group. Resting-state functional magnetic resonance imaging and heart rate variability are used to investigate the therapeutic mechanisms. Statistical analysis is performed using an intention-to-treat analysis. Discussion This study will partially illustrate that acupuncture at the Balian acupoints can modulate autonomic nervous activity and specific brain region activity to relieve functional constipation. Trial registration This trial is registered in ClinicalTrials.gov (Identifier number: NCT07010367, register date: 2025-06-07). Ethical approval was obtained from The Ethics Committee of Guang’anmen Hospital, China Academy of Chinese Medical Sciences (approval number: 2025-020-QS). Acupuncture Functional constipation Resting-state functional magnetic resonance imaging Heart rate variability Figures Figure 1 Figure 2 Background Functional constipation (FC) is a disorder of gut-brain interaction associated with dysfunctional colonic motility and/or outlet dysfunction without mucosal or structural abnormalities, and is characterized by symptoms such as infrequent or incomplete defecation [1-2]. It affects approximately 10.1%-15.3% of the global population [3]. This condition significantly diminishes the quality of life and imposes a huge economic burden on public health care. The Bowel Interest Group reported that £162 million per year was spent by National Health Service on treating FC [4], and 21.3%-40% of those who suffer from constipation experienced anxiety disorder or depression [5-6]. Constipation can cause fecal impaction, chronic pain, increased cardiovascular adverse events, and is becoming one of the most common secondary health impacts [7]. There is no curative or satisfactory therapy for FC. A 5-year nationwide study of adult FC participants in the United States showed that two-thirds of patients with FC are not satisfied with their treatment [8]. Lifestyle management, such as dietary fiber intake, adequate hydration, and engaging in regular exercise, are common first-line therapies for FC, but their effectiveness appears limited and uncertain. A meta-analysis involving 1,251 participants found that 34% of the participants did not respond to fiber treatment [9]. Over-the-counter (OTC) agents, such as fiber products, probiotics, and osmotic laxatives, are usually used for mild constipation [10]. Stimulant laxatives, secretagogues, and 5-HT4 agonists can be used as replacement or adjunct options when patients do not respond to OTC agents, [11]. Both OTC agents and prescription drugs have the potential to cause dependency and common side effects such as bloating, abdominal pain, and diarrhea. Surgical management is performed when conservative measures fail [12]. A systematic review of seven studies illustrated that sacral nerve stimulation has a high complication rate (13%-34%) and is inconsistent in efficacy [13]. Colonic resection might benefit patients with refractory constipation, but this comes at the cost of significant short-term and long-term complications [14]. Overall, there is an urgent need for improved bowel care. Acupuncture is an ancient form of traditional Chinese medicine that dates back over 3,000 years [15]. When acupuncture needles are placed in specific points, energy (chi) is redirected to bring about a healing response. The World Health Organization recognizes acupuncture as an effective treatment for over 35 common illnesses. Results from several meta-analyses suggest that acupuncture can increase weekly complete spontaneous bowel movements, improve quality of life, and is free from severe adverse events [16-19]. It has also been reported that the positive effect can sustain for several weeks after a standard course of treatment [17]. The effects of acupuncture on constipation lack high-quality evidence. In terms of study design, some studies did not set non-inferiority or superiority margins, therefore, the possibility of an elaborated placebo effect should not be excluded. A strong placebo response of sham acupuncture was found in dyspepsia, dysmenorrhea, obesity [20-22]. Current evidence suggests that many factors, such as expectation and belief, unrelated to acupuncture needling may play important roles in its beneficial effects [23]. For primary outcomes, given the subjective nature of self-reported outcomes widely used in functional constipation assessment, consistency among studies remains poor [24]. In addition, many studies lack a specific description of sequence generation or allocation concealment, and the results are not displayed in a standard statement [24]. The mechanisms of acupuncture in treating constipation are only beginning to be understood. Evidence shows that patients with functional constipation are associated with abnormal brain activation in the limbic system-cerebral cortex and white matter microstructural alterations [25-27]. Baliao acupoints are empirical points for the treatment of constipation, located in the four pairs of sacral foramina. The location of the Baliao acupoints is close to the sacral nerves. Stimulation in Baliao may promote intestinal peristalsis by exciting the parasympathetic nerves and might also influence the functional activities of the brain through the pathway of ‘stimulation-visceral afferent nerves-spinal cord-thalamus’ [28]. Thus, this study proposes a hypothesis that ‘acupuncture at the Balian acupoints can modulate autonomic nervous activities and specific brain region activities to produce therapeutic effects on functional constipation’. The study was conducted with patients with functional constipation, using acupuncture at the Baliao acupoints as an intervention and sham acupuncture as a control. Based on the resting-state functional magnetic resonance imaging (fMRI) technique and portable heart rate variability (HRV) device, the study focused on the patients’ weekly number of complete spontaneous bowel movements, and its correlation with the abnormal functional activities of ‘visceral afferent nerves-thalamus-cortex’ pathway. Methods Study design This is a multicenter, superiority, parallel, randomized controlled trial. Participants diagnosed with functional constipation by Rome IV is allocated to treatment (Baliao acupuncture group) and control (sham-acupuncture group) groups at a 1:1 ratio. The study is conducted in three tertiary-A hospitals in China: Guang'anmen Hospital of China Academy of Chinese Medical Sciences, Affiliated Hospital of Nanjing University of Chinese Medicine, and Xiyuan Hospital of China Academy of Chinese Medical Sciences. The study duration per participant is 10 weeks: 2 weeks before allocation (baseline assessment), 4 weeks of intervention, and 4 weeks of follow-up without treatment. The graphic design of this study is illustrated in Figure 1. The time frame of the trial is presented in Table 1. Objectives This study aims to evaluate the effect of acupuncture at Baliao acupoints in functional constipation and investigate the interactions among acupuncture-induced improvement of constipation symptoms, changes in autonomic nerve system activities, and regulation of brain functional activities. Participants Inclusion criteria Adult participants diagnosed with functional constipation according to the Rome IV criteria will be included in this study [29]. Participants should not have received treatment for functional constipation within the past 2 weeks (excluding emergency interventions such as glycerol enema). All participants are right-handed. Written informed consent is needed. Rome IV Functional constipation diagnostic criteria: 1. Must include two or more of the following: straining during more than 25% of defecations, lumpy or hard stools more than 25% of defecations, a sense of anorectal obstruction/blockage more than 25% of defecations, a sense of incomplete evacuation more than 25% of defecations, manual maneuvers to facilitate more than 25% of defecations, fewer than three spontaneous bowel movements per week; 2. Loose stools rarely occur without the use of laxatives; 3. Insufficient criteria for irritable bowel syndrome; 4. The criteria above were fulfilled for the last three months with symptom onset for at least six months prior to diagnosis. Exclusion criteria Patients with organic constipation, drug-induced constipation, or systemic constipation should be excluded. Participants with contraindications to magnetic resonance imaging (MRI), such as a cardiac pacemaker, should be excluded. Participants with a history of traumatic brain injury, migraine, or mental disorders should be excluded. Pregnant women should be excluded. Eligibility criteria for healthcare providers Anorectal physicians will make diagnoses, screen candidates for study participation, assess outcomes and analyze data. All physicians had at least a five-year undergraduate medical education. Acupuncturists will provide the interventions. All acupuncturists were registered practitioners of traditional Chinese medicine. All healthcare providers received a training course before the study initiation. Discontinuing criteria Participants who develop infection or allergic reaction at the acupuncture site; participants who do not follow the treatment plan or do not cooperate with follow-up visits. Informed consent Anorectal physicians will obtain informed consent from the potential participants. Participants will be informed that they will be randomly allocated to either the Baliao acupuncture group or sham acupuncture group, and they will be made aware of the potential benefits and risks associated with the study. Participants will have the right to withdraw from the study at any time based on their own decision. Informed consent is available in Supplementary material 1. Sample size This is a superiority randomized controlled trial. The treatment group receives acupuncture and the control group receives sham acupuncture treatment. The allocation rate is 1:1. The primary outcome is the change from baseline in CSBMs per week. According to our pilot study, we assumed an effect size of 2.61 and a variance of 2.25. The superiority margin was set at 1.5 based on the minimal clinically important difference. 84 participants for each group (28 for each site), a total of 168 participants would be needed to provide 90% power to detect a superiority margin of 2 with a 2-sided α of 0.05, allowing a 15% dropout rate. The sample size was calculated by PASS 2023 (NCSS, Kaysville, Utah, USA). Randomization and blinding A computer-generated random allocation sequence will be generated by a research assistant. The participants will be assigned to the acupuncture group and the sham acupuncture group at a ratio of 1:1. The allocation sequence will be placed in opaque and sealed envelopes by the research assistant. The acupuncturist will open the envelope before the intervention. The participants, outcome assessors, and data analysts are blinded. The two groups have similar intervention locations, with the same duration and frequency of treatment. Participants are instructed to lie prone during the intervention and could not see the specific procedures, which also help prevent them from knowing their group allocation in advance. Intervention Physicians will provide participants with a detailed explanation of the study background and procedures. Throughout the study, physicians will maintain regular communication with participants to respond to any questions or concerns. In both groups, participants without bowel movements for three or more consecutive days are allowed to use 110-220 mL glycerol enema (Beijing Maidihai Pharmaceutical Co., Ltd., Beijing, China) or lactulose oral solution 30mL (Abobott Biologicals B.V., OLST, The Netherlands) as a rescue intervention with documentation in the case report form (CRF). Other medications for constipation will not be permitted. Baliao acupuncture group Participants in the Baliao acupuncture group will receive acupuncture at Baliao acupoints. Baliao acupoints are consist of Shangliao (BL31), Ciliao (BL32), Zhongliao (BL33), Xialiao (BL34) (Figure 2), Patients will be instructed to lie in prone position. After strict disinfection of the acupoint area, disposable acupuncture needles (Huatuo, Suzhou Medical Supplies Factory Co., Ltd., Suzhou, China) will be inserted into the Baliao acupoints for 3–4 cm. Equal needle manipulations will be performed. The treatment will be administered five times per week, with each session lasting 30 min, for a total of four weeks. The specific operating steps are as follows: First, locate acupoints. Locate the posterior midline of the sacrum and palpate the sacral depressions on both sides with your fingertips. The first to fourth pairs of sacral foramina are located in these depressions, which correspond to the Shangliao (BL31), Ciliao (BL32), Zhongliao (BL33), Xialiao (BL34) acupoints, respectively. When the fourth pair of sacral foramina is difficult to locate, acupuncture at Xialiao (BL34) should not be performed for safety considerations [30]. Second, insert the needles. Acupuncture needles will be inserted into the first, second, third, and fourth pairs of sacral foramina, with a depth of 3–4 cm according to the participants’ body habitus. Third, perform manipulations. When the needles are placed in the right position, participants will experience a needling sensation of soreness, numbness, distension, or heaviness. In this case, the acupuncturist will perform equal manipulations of twirling (both clockwise and anticlockwise), lifting, and thrusting (once every 10 min) to enhance and maintain the needling sensation [31]. Sham acupuncture group Participants in sham acupuncture group will receive shallow needling at sham Baliao acupoints. Patients will be instructed to lie in prone position. After strict disinfection of the sham acupoint area, acupuncture needles (Huatuo, Suzhou Medical Supplies Factory Co., Ltd., Suzhou, China) will be inserted 5 mm away from the surface projections of the first, second, third, and fourth pairs of sacral foramina. Then, pinch the skin between the thumb and index finger. Insert the acupuncture needle at a 15-degree angle to the skin surface to a depth of 5 mm. Be careful not to penetrate the periosteum. Participants should not feel the needling sensation of soreness, numbness, distension, or heaviness. No manipulations of twirling, lifting, and thrusting will be performed. The treatment will be administered five times per week, with each session lasting 30 min, for a total of four weeks. Outcomes Primary outcome The primary outcome is the change from baseline in complete spontaneous bowel movements (CSBMs) per week during treatment and follow-up period. CSBM is defined as a spontaneous bowel movement (SBM) associated with a sense of complete defecation. An SBM is a bowel movement that occurs without the use of laxatives, enemas, or other rescue interventions/assistance in the previous 24 hours. Secondary outcomes The secondary outcomes are the change from baseline in SBMs per week during treatment and follow-up period, the change from baseline in patient assessment of constipation symptoms (PAC-SYM) scores and patient assessment of constipation quality of life questionnaire (PAC-QOL) scores at week 4 and week 8. PAC-SYM is an instrument used to evaluate the symptoms and severity of constipation. It consists of three parts: stool symptoms, rectal symptoms, and abdominal symptoms, with a total of 12 items. The score ranges from 0 to 48, with higher scores indicating more severe constipation symptoms. PAC-QOL is an instrument used to assess the impairment of constipation on patients’ quality of life. It consists of four dimensions: physical discomfort, psychosocial discomfort, worry and discomfort, and treatment satisfaction, with 28 items. The score ranges from 0 to 112, with higher scores indicating a greater negative impact on quality of life [32-33]. Mechanism outcomes fMRI MRI scans will be conducted using a Siemens 3.0T Skyra MRI scanner (Siemens AG, Munich, Germany) at baseline period, week 4, and week 8. To minimize brain functional changes caused by discomfort in new environment, a separate empty scan will be performed for 30 seconds. Participants will be instructed to remain quiet, with their eyes closed and without performing any specific tasks in a supine position. Structural Brain Imaging: T1-weighted imaging (T1WI) data is acquired using MPRAGE sequence. The scan parameters were as follows: TR = 15 ms, TE = 6.9 ms, flip angle = 15°, FOV = 256 mm × 256 mm. A total of 196 sagittal slices were scanned with a slice thickness of 1 mm and no interslice gap. Resting-state fMRI: Resting-state fMRI data is acquired using blood oxygen level-dependent gradient echo-echo planar imaging (BOLD GRE-EPI) sequence. The scan parameters were as follows: TR/TE = 2000ms/30ms, flip angle = 90°, FOV = 240 mm × 240 mm, matrix = 70 × 70, slice thickness = 3.0 mm, no interslice gap, number of slices = 48. A total of 240 time points will be scanned, with a scan duration of 8 min. Amplitude of Low-Frequency Fluctuations (ALFF), Regional Homogeneity (ReHo), and functional connectivity (FC) will be extracted from resting-state fMRI. ALFF measures the intensity of neuronal activity. The higher the value, the more active the neuronal activity. ReHo measures the consistency and synchronicity of neuronal activity. The higher the value, the more synchronized the neuronal activity. Functional connectivity refers to the temporal correlation between low-frequency blood oxygen level-dependent (BOLD) signals in different brain regions, reflecting the ability of these regions to work in coordination with each other [34]. Heart rate variability (HRV) HRV signals will be collected at baseline period, week 4, and week 8 using a mobile electrocardiogram (ECG) recorder 8Z11 (Wegene Technology Inc., Shenyang, China). The participants need to hold the side pads of the ECG recorder with both hands and maintain a state of quietness, relaxation, and without performing any specific task for 5 min. After data collection is completed, the ECG data will automatically upload to the Wegene Technology ECG signal analysis system (Wegene Technology Inc., Shenyang, China) to calculate the standard deviation of normal-to-normal intervals (SDNN), root mean square of successive differences (RMSSD), proportion of adjacent RR intervals differing by more than 50 ms (pNN50), low-frequency component (LF), high-frequency component (HF), and LF/HF. SDNN reflects the overall variability of HRV. RMSSD reflects the activity of the parasympathetic nervous system. pNN50 reflects the activity of the parasympathetic nervous system. LF reflects sympathetic nervous system activity. HF reflects parasympathetic nervous system activity. LF/HF reflects the balance between sympathetic and parasympathetic nervous system activities [35]. Psychological outcomes Psychological outcomes are the changes from baseline in anxiety or depression proportion. Psychological assessment will be performed at baseline period, week 4 and week 8. The Zung self-rating anxiety Scale (SAS) and the Zung self-rating depression scale (SDS) will be used to assess the patients’ anxiety and depression status. A standard score of ≥50 on the SAS and ≥53 on the SDS indicates anxiety and depression, respectively. Higher score indicates greater anxiety and depression. It should be noted that these scales measure the degree of anxiety and depression but should not be used as a diagnostic tool for anxiety or depressive disorders [36-37]. Safety Evaluation This study is associated with low to moderate risks. All adverse events will be documented, managed, and followed up until they are satisfactorily resolved, or the condition is stabilized. Anticipated adverse events include but are not limited to: Local infection, bleeding, hematoma, needle allergy, needle bending, dizziness, fatigue, fainting because of needling, electrolyte disturbances, cardiovascular adverse events caused by difficulty in defecation, and mechanical ileus caused by constipation. If a participant experienced dizziness, fatigue, or fainting caused by needling, the acupuncturist will stop needling immediately. Participants with mild or moderate adverse events will be treated by symptom. Severe adverse events will be managed proactively and reported to research ethics committee and data monitoring committee. Data collection, management and monitor Participants are required to record a stool diary to minimize recall bias. The stool diary can be recorded on a Wechat application named ‘poop diary’ or a notebook for those who have difficulty using a digital device. We recommend participants record the diary at a fixed time every day in case of forgetting. Clinical data is collected using CRF by anorectal physicians. A research assistant will compile the data collected from the CRF and stool diary into an Excel spreadsheet, which will then be proofread by another research assistant. Anorectal physicians and research assistants will receive training on data collection standards. The data monitoring committee is composed of clinical experts, statisticians, and ethicists. It regularly reviews the study data to assess the risks and benefits of the study as well as the safety of the participants. All members are free from conflicts of interest and are not influenced by the study sponsor. Statistical Analysis Clinical data analysis The null hypothesis is that the change from baseline in mean CSBMs per week would be the same for the acupuncture group and the sham acupuncture group, and the alternative hypothesis is that the acupuncture group is superior to sham group. The superiority margin was set at 1.5 based on the minimal clinically important difference. The acupuncture group will be considered superior to the sham acupuncture group when the lower limit of the 95% confidence interval for the group difference exceeds the superiority margin. Analyses will be based on the intention-to-treat principle. Missing data will be filled by multiple imputation. Continuous variables that follow a normal distribution are presented as means ± standard deviations (SD), while those that do not follow are presented as medians (interquartile ranges) (IQR). Categorical variables are presented as frequency (percentages). Comparisons between groups will be made using t-tests, Mann-Whitney U tests, or Chi-square tests, as appropriate. All statistical tests is 2-sided. P value of < 0.05 is considered significant. MRI analysis DPABI _ V9.0_250415 (http://rfmri.org/DPABI), a MATLAB toolbox, will be used to process and analysis brain imaging data. First, use DPARSF Advanced Edition (DPARSFA) module to pre-process data: remove first 10 time points, slice timing correction, head motion correction, spatial normalization, spatial smoothing, detrend. And then calculate ALFF/fALFF, ReHo. Second, use DPABI Statistical Analysis module to conduct t-tests for ALFF/fALFF and ReHo between pre- and post-treatment. Third, define regions of interest (ROI) based on the results and literature review, and then obtain FC using DPARSFA. Ethical considerations Research ethical committee approval is obtained by The Ethics Committee of Guang’anmen Hospital, China Academy of Chinese Medical Sciences (approval number: 2025-KY-108). The research is registered in ClinicalTrials.gov (Identifier number: NCT07010367). During the research process, the personal privacy of participants and the confidentiality of data will be strictly protected. Personal information of participants will not be disclosed. The study findings will be published in accordance with academic standards. Discussion Constipation can pose negative impact on physical, social, and emotional well-being. Patient-reported outcomes are highly important when assessing therapeutic efficacy. Different populations may differ in descriptions of symptoms and reaction to stimulations [38-39], so we also need to introduce biomarkers to describe therapeutic efficacy objectively, especially regarding to explain mechanism. There are no widely recognized biomarkers for functional constipation that possess both high sensitivity and specificity. Most of them are experimental and lack of sufficient high-quality evidence in clinical practice. HRV and fMRI are promising biomarkers for functional constipation [40-41]. Gastrointestinal motility is regulated by the enteric nervous system (ENS), the autonomic nervous system (ANS), and the central nervous system (CNS) [42]. Heart rate variability is a non-invasive technique to monitor autonomic nervous system. The vagus nerve primarily exerts an inhibitory effect on the gastrointestinal tract, while the sympathetic nervous system inhibits gastrointestinal motility and secretory functions. Patients with functional bowel disorders often exhibit alterations in autonomic nervous system function [43]. fMRI is a non-invasive tool that allows mapping of human brain functions. It is reported that patients with functional constipation show significantly increased amplitude of low-frequency fluctuations (ALFF) in the right anterior insula, hippocampus, dorsal anterior cingulate cortex, and orbitofrontal cortex, while the ALFF in the precentral gyrus and supplementary motor area is significantly decreased [44]. Additionally, there is reduced functional connectivity between the thalamus and the parietal cortex [45]. This means that there are abnormalities in visceral activity and sensory processing in patients with functional constipation. Therefore, it is hypothesized that acupuncture at the Balian acupoints can modulate autonomic nervous activity and specific brain region activity to produce therapeutic effects on functional constipation. Limitation such as information bias should be noted in this study. No common consensus has been reached on how to design a control group in acupuncture study and sham acupuncture is a common choice in previous literature [46]. In this study, despite the two groups have a similar intervention area, the acupuncture needles in the sham group won’t insert as deep as the acupuncture group, and there are no needle manipulations in the sham group, thus participants will experience different needling sensation, especially for those who experienced acupuncture. There are possibilities that participants in the sham group might know which intervention they have received before unblinding. We will compare the proportions of participants who manage to know that they had received actual acupuncture between groups by a Chi-square test to examine whether the blinding is successful. Further research is needed to investigate its long-term efficacy, the utility of intermittent treatment, as well as the cost-effectiveness and cost-utility analysis of the treatment. List of abbreviations BL31, Shangliao BL32, Ciliao BL33, Zhongliao BL34, Xialiao BOLD, low-frequency blood oxygen level-dependent CRF, case report form CSBMs, complete spontaneous bowel movements fMRI, functional magnetic resonance imaging HF, high-frequency component HRV, heart rate variability LF, low-frequency component PAC-QoL, patient assessment of constipation quality of life PAC-SYM, patient assessment of constipation symptoms pNN50, proportion of adjacent RR intervals differing by more than 50 ms RMSSD, root mean square of successive differences SDNN, standard deviation of normal-to-normal intervals SDS, self-rating depression scale SAS, self-rating anxiety scale SBMs, spontaneous bowel movements Declarations Ethics approval and consent to participate Research ethical committee approval is obtained by The Ethics Committee of Guang’anmen Hospital, China Academy of Chinese Medical Sciences (approval number: 2025-KY-108). Participants recruitment is ongoing. Informed consent will be obtained from all participants. Consent for publication Not applicable. Availability of data and materials Data are available from the corresponding author upon reasonable request. Competing interests The authors declare that they have no competing interests. Funding Funding: This trial is supported by the Central Government’s Clinical Research Fund for High-Level TCM Hospitals (No. HLCMHPP2023131). The funding organization has no role in the study design, conduct, or decision-making for publication. Authors' contributions Wei Chen designed the study and prepared the first draft of the manuscript, Qu muwen provided edits and critique. All authors read and approved the final manuscript. Acknowledgements Not applicable. References Alavi K, Thorsen AJ, Fang SH, et al. The American Society of Colon and Rectal Surgeons Clinical Practice Guidelines for the Evaluation and Management of Chronic Constipation. 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The gut-brain axis and cognitive control: A role for the vagus nerve. Semin Cell Dev Biol. 2024,156:201-209. doi:10.1016/j.semcdb.2023.02.004 Drossman DA. Functional Gastrointestinal Disorders: History, Pathophysiology, Clinical Features and Rome IV. Gastroenterology. 2016;150(6):1262-1279. doi:10.1053/j.gastro.2016.02.032. Pandey M. A study on anatomical variations of sacral foramina and its clinical relevance international journal of anatomy. Int J Anat Radiol Surg. 2021;10(1): AO10-AO12. doi: 10.7860/IJARS/2021/45487:2593 Zhou K, Fang J, Wang X, et al. Characterization of de qi with electroacupuncture at acupoints with different properties. J Altern Complement Med. 2011;17:1007-1013. doi:10.1089/acm.2010.0652 L Frank L, Kleinman L, Farup C, Taylor L, Miner P Jr. Psychometric validation of a constipation symptom assessment questionnaire. Scand J Gastroenterol. 1999;34(9):870-877. doi: 10.1080/003655299750025327 Marquis P, De La Loge C, Dubois D, McDermott A, Chassany O. Development and validation of the Patient Assessment of Constipation Quality of Life questionnaire. Scand J Gastroenterol. 2005;40(5):540-551. doi:10.1080/00365520510012208 Cattarinussi G, Heidari-Foroozan M, Jafary H, et al. Resting-state functional magnetic resonance imaging alterations in first-degree relatives of individuals with bipolar disorder: A systematic review. J Affect Disord. 2024;365:321-331. doi:10.1016/j.jad.2024.08.040 Olivieri F, Biscetti L, Pimpini L, Pelliccioni G, Sabbatinelli J, Giunta S. Heart rate variability and autonomic nervous system imbalance: Potential biomarkers and detectable hallmarks of aging and inflammaging. Ageing Res Rev. 2024;101:102521. doi:10.1016/j.arr.2024.102521 Zung WW. A self-rating depression scale. Arch Gen Psychiatry. 1965;12:63-70. doi:10.1001/archpsyc.1965.01720310065008 Zung WW. A rating instrument for anxiety disorders. Psychosomatics. 1971;12(6):371-379. doi:10.1016/S0033-3182(71)71479-0 Gerson CD, Gerson MJ, Awad RA, et al. Irritable bowel syndrome: an international study of symptoms in eight countries. Eur J Gastroenterol Hepatol. 2008;20(7):659-667. doi:10.1097/MEG.0b013e3282f53a24 Talley NJ, Weaver AL, Zinsmeister AR, Melton LJ 3rd. Functional constipation and outlet delay: a population-based study. Gastroenterology. 1993;105(3):781-790. doi:10.1016/0016-5085(93)90896-k Ali MK, Chen JDZ. Roles of Heart Rate Variability in Assessing Autonomic Nervous System in Functional Gastrointestinal Disorders: A Systematic Review. Diagnostics (Basel). 2023;13(2):293. doi:10.3390/diagnostics13020293 Mayer EA, Naliboff BD, Craig AD. Neuroimaging of the brain-gut axis: from basic understanding to treatment of functional GI disorders. Gastroenterology. 2006;131(6):1925-1942. doi:10.1053/j.gastro.2006.10.026 Margolis KG, Cryan JF, Mayer EA. The Microbiota-Gut-Brain Axis: From Motility to Mood. Gastroenterology. 2021;160(5):1486-1501. doi:10.1053/j.gastro.2020.10.066 Liu J, Lv C, Yin M, et al. Efficacy and safety of transcutaneous auricular vagus nerve stimulation in patients with constipation-predominant irritable bowel syndrome: a single-center, single-blind, randomized controlled trial. Am J Gastroenterol. 2024; doi:10.14309/ajg.0000000000003257 Zhu Q, Cai W, Zheng J, et al. Distinct resting-state brain activity in patients with functional constipation. Neurosci Lett. 2016;632:141-146. doi:10.1016/j.neulet.2016.08.042 Ma PH, Yin T, He ZX, et al. Alterations of White Matter Network Properties in Patients With Functional Constipation. Front Neurol. 2021;12:627130. doi:10.3389/fneur.2021.627130 Xiong Z, Ma P, Zhang H, et al. Placebo response to sham electroacupuncture in patients with chronic functional constipation: A secondary analysis. Neurogastroenterol Motil. 2024;36(5):e14770. doi:10.1111/nmo.14770 Tables Table 1 is available in the Supplementary Files section. Additional Declarations No competing interests reported. Supplementary Files supplementarymaterial1InformedConsentForm.docx Supplementary material 1 - Informed consent supplementarymaterial2SPIRITChecklist.pdf Supplementary material 2 - SPIRIT checklist Table1.doc Cite Share Download PDF Status: Under Review Version 1 posted Reviewers invited by journal 01 May, 2026 Editor assigned by journal 13 Aug, 2025 Submission checks completed at journal 13 Aug, 2025 First submitted to journal 12 Aug, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7351160","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Study protocol","associatedPublications":[],"authors":[{"id":633126834,"identity":"fdb7a638-e11b-4565-a692-00890a3f507d","order_by":0,"name":"Chen Wei","email":"","orcid":"","institution":"China Academy of Chinese Medical Sciences","correspondingAuthor":false,"prefix":"","firstName":"Chen","middleName":"","lastName":"Wei","suffix":""},{"id":633126835,"identity":"52fed659-0d16-4705-927f-fd093ef1f6f7","order_by":1,"name":"Muwen Qu","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAv0lEQVRIiWNgGAWjYBADA35m5sMPSNMi2c6WZkCaFoPzPAoSRCmVdz+dJs3zy87Y+DAPgwFDjU00QS2GZ3K3SfP2JZuZHeY98IDhWFpuA0EtDSAtPQdszA7zJRgwNhwmQkv/W4gW42YeAwmitMhLAG3h+XHAzICZWC0GEm83W85tSDaWOAwM5ARi/CLfn7vxxps/dob9/YcPP/hQY0OELQcYWKR426C8BELKwbY0MDB//PGHGKWjYBSMglEwYgEAeWg/haSzQjcAAAAASUVORK5CYII=","orcid":"","institution":"China Academy of Chinese Medical Sciences","correspondingAuthor":true,"prefix":"","firstName":"Muwen","middleName":"","lastName":"Qu","suffix":""}],"badges":[],"createdAt":"2025-08-12 04:23:17","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7351160/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7351160/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":109099933,"identity":"cd15ce04-7ee4-4b47-b080-14dd4828da1a","added_by":"auto","created_at":"2026-05-12 14:19:24","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":337161,"visible":true,"origin":"","legend":"\u003cp\u003eStudy flow chart\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFigure 1 legends.\u003c/strong\u003e CSBMs, complete spontaneous bowel movements; ITT, intention-to-treat.\u003c/p\u003e","description":"","filename":"Figure1flowchart.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7351160/v1/a14a6147707f96ca8390d9a6.jpg"},{"id":109100002,"identity":"caee098d-6b85-476e-8d84-5d700f972355","added_by":"auto","created_at":"2026-05-12 14:19:41","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":603503,"visible":true,"origin":"","legend":"\u003cp\u003eLocation of acupoints and sham acupoints\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFigure 2 legends. \u003c/strong\u003eYellow dots represent acupoint, blue dots represent sham acupoint. BL31, Shangliao; BL32, Ciliao; BL33, Zhongliao; BL34, Xialiao.\u003c/p\u003e","description":"","filename":"Figure2baliaolocation.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7351160/v1/faf0a828efefdfa9a5205702.jpg"},{"id":109100301,"identity":"4bc99d32-c58f-4bc5-b408-7c7f0563bfd3","added_by":"auto","created_at":"2026-05-12 14:21:03","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1151879,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7351160/v1/215242dd-5441-46c2-be20-2cbcd00136c0.pdf"},{"id":109100106,"identity":"bad2b230-fd96-4a7d-8623-9642d43b7e89","added_by":"auto","created_at":"2026-05-12 14:19:58","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":23595,"visible":true,"origin":"","legend":"\u003cp\u003eSupplementary material 1 - Informed consent\u003c/p\u003e","description":"","filename":"supplementarymaterial1InformedConsentForm.docx","url":"https://assets-eu.researchsquare.com/files/rs-7351160/v1/2f54b4acef761ce20c0fd884.docx"},{"id":109100070,"identity":"fc430687-3882-4b04-9c14-8ef588d4693a","added_by":"auto","created_at":"2026-05-12 14:19:52","extension":"pdf","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":945039,"visible":true,"origin":"","legend":"\u003cp\u003eSupplementary material 2 - SPIRIT checklist\u003c/p\u003e","description":"","filename":"supplementarymaterial2SPIRITChecklist.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7351160/v1/62c574f98cf2a912bc1f06fd.pdf"},{"id":109100074,"identity":"3f09fca2-cba0-4c36-bc6a-15dabea140b9","added_by":"auto","created_at":"2026-05-12 14:19:54","extension":"doc","order_by":3,"title":"","display":"","copyAsset":false,"role":"supplement","size":56320,"visible":true,"origin":"","legend":"","description":"","filename":"Table1.doc","url":"https://assets-eu.researchsquare.com/files/rs-7351160/v1/fbe3dbae5add37e95bc81bcb.doc"}],"financialInterests":"No competing interests reported.","formattedTitle":"Effect of acupuncture at Baliao (BL31, BL32, BL33, BL34) on complete spontaneous bowel movements in functional constipation patients: study protocol for a randomized sham-controlled trial","fulltext":[{"header":"Background","content":"\u003cp\u003eFunctional constipation (FC) is a disorder of gut-brain interaction associated with dysfunctional colonic motility and/or outlet dysfunction without mucosal or structural abnormalities, and is characterized by symptoms such as infrequent or incomplete defecation [1-2]. It affects approximately 10.1%-15.3% of the global population [3]. This condition significantly diminishes the quality of life and imposes a huge economic burden on public health care. The Bowel Interest Group reported that \u0026pound;162 million per year was spent by National Health Service on treating FC [4], and 21.3%-40% of those who suffer from constipation experienced anxiety disorder or depression [5-6]. Constipation can cause fecal impaction, chronic pain, increased cardiovascular adverse events, and is becoming one of the most common secondary health impacts [7].\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThere is no curative or satisfactory therapy for FC. A 5-year nationwide study of adult FC participants in the United States showed that two-thirds of patients with FC are not satisfied with their treatment [8]. Lifestyle management, such as dietary fiber intake, adequate hydration, and engaging in regular exercise, are common first-line therapies for FC, but their effectiveness appears limited and uncertain. A meta-analysis involving 1,251 participants found that 34% of the participants did not respond to fiber treatment [9]. Over-the-counter (OTC) agents, such as fiber products, probiotics, and osmotic laxatives, are usually used for mild constipation [10]. Stimulant laxatives, secretagogues, and 5-HT4 agonists can be used as replacement or adjunct options when patients do not respond to OTC agents, [11]. Both OTC agents and prescription drugs have the potential to cause dependency and common side effects such as bloating, abdominal pain, and diarrhea. Surgical management is performed when conservative measures fail [12]. A systematic review of seven studies illustrated that sacral nerve stimulation has a high complication rate (13%-34%) and is inconsistent in efficacy [13]. Colonic resection might benefit patients with refractory constipation, but this comes at the cost of significant short-term and long-term complications [14]. Overall, there is an urgent need for improved bowel care.\u003c/p\u003e\n\u003cp\u003eAcupuncture is an ancient form of traditional Chinese medicine that dates back over 3,000 years [15]. When acupuncture needles are placed in specific points, energy (chi) is redirected to bring about a healing response. The World Health Organization recognizes acupuncture as an effective treatment for over 35 common illnesses. Results from several meta-analyses suggest that acupuncture can increase weekly complete spontaneous bowel movements, improve quality of life, and is free from severe adverse events [16-19]. It has also been reported that the positive effect can sustain for several weeks after a standard course of treatment [17].\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe effects of acupuncture on constipation lack high-quality evidence. In terms of study design, some studies did not set non-inferiority or superiority margins, therefore, the possibility of an elaborated placebo effect should not be excluded. A strong placebo response of sham acupuncture was found in dyspepsia, dysmenorrhea, obesity [20-22]. Current evidence suggests that many factors, such as expectation and belief, unrelated to acupuncture needling may play important roles in its beneficial effects [23]. For primary outcomes, given the subjective nature of self-reported outcomes widely used in functional constipation assessment, consistency among studies remains poor [24]. In addition, many studies lack a specific description of sequence generation or allocation concealment, and the results are not displayed in a standard statement [24].\u003c/p\u003e\n\u003cp\u003eThe mechanisms of acupuncture in treating constipation are only beginning to be understood. Evidence shows that patients with functional constipation are associated with abnormal brain activation in the limbic system-cerebral cortex and white matter microstructural alterations [25-27]. Baliao acupoints are empirical points for the treatment of constipation, located in the four pairs of sacral foramina. The location of the Baliao acupoints is close to the sacral nerves. Stimulation in Baliao may promote intestinal peristalsis by exciting the parasympathetic nerves and might also influence the functional activities of the brain through the pathway of \u0026lsquo;stimulation-visceral afferent nerves-spinal cord-thalamus\u0026rsquo; [28].\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThus, this study proposes a hypothesis that \u0026lsquo;acupuncture at the Balian acupoints can modulate autonomic nervous activities and specific brain region activities to produce therapeutic effects on functional constipation\u0026rsquo;. The study was conducted with patients with functional constipation, using acupuncture at the Baliao acupoints as an intervention and sham acupuncture as a control. Based on the resting-state functional magnetic resonance imaging (fMRI) technique and portable heart rate variability (HRV) device, the study focused on the patients\u0026rsquo; weekly number of complete spontaneous bowel movements, and its correlation with the abnormal functional activities of \u0026lsquo;visceral afferent nerves-thalamus-cortex\u0026rsquo; pathway.\u003c/p\u003e"},{"header":"Methods ","content":"\u003cp\u003e\u003cstrong\u003eStudy design\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis is a multicenter, superiority, parallel, randomized controlled trial. Participants diagnosed with functional constipation by Rome IV is allocated to treatment (Baliao acupuncture group) and control (sham-acupuncture group) groups at a 1:1 ratio. The study is conducted in three tertiary-A hospitals in China: Guang\u0026apos;anmen Hospital of China Academy of Chinese Medical Sciences, Affiliated Hospital of Nanjing University of Chinese Medicine, and Xiyuan Hospital of China Academy of Chinese Medical Sciences. The study duration per participant is 10 weeks: 2 weeks before allocation (baseline assessment), 4 weeks of intervention, and 4 weeks of follow-up without treatment. The graphic design of this study is illustrated in Figure 1. The time frame of the trial is presented in Table 1.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eObjectives\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study aims to evaluate the effect of acupuncture at Baliao acupoints in functional constipation and investigate the interactions among acupuncture-induced improvement of constipation symptoms, changes in autonomic nerve system activities, and regulation of brain functional activities.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eParticipants\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eInclusion criteria\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAdult participants diagnosed with functional constipation according to the Rome IV criteria will be included in this study [29]. Participants should not have received treatment for functional constipation within the past 2 weeks (excluding emergency interventions such as glycerol enema). All participants are right-handed. Written informed consent is needed.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eRome IV Functional constipation diagnostic criteria: 1. Must include two or more of the following: straining during more than 25% of defecations, lumpy or hard stools more than 25% of defecations, a sense of anorectal obstruction/blockage more than 25% of defecations, a sense of incomplete evacuation more than 25% of defecations, manual maneuvers to facilitate more than 25% of defecations, fewer than three spontaneous bowel movements per week; 2. Loose stools rarely occur without the use of laxatives; 3. Insufficient criteria for irritable bowel syndrome; 4. The criteria above were fulfilled for the last three months with symptom onset for at least six months prior to diagnosis.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eExclusion criteria\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003ePatients with organic constipation, drug-induced constipation, or systemic constipation should be excluded. Participants with contraindications to magnetic resonance imaging (MRI), such as a cardiac pacemaker, should be excluded. Participants with a history of traumatic brain injury, migraine, or mental disorders should be excluded. Pregnant women should be excluded.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEligibility criteria for healthcare providers\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAnorectal physicians will make diagnoses, screen candidates for study participation, assess outcomes and analyze data. All physicians had at least a five-year undergraduate medical education. Acupuncturists will provide the interventions. All acupuncturists were registered practitioners of traditional Chinese medicine. All healthcare providers received a training course before the study initiation.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDiscontinuing criteria\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eParticipants who develop infection or allergic reaction at the acupuncture site; participants who do not follow the treatment plan or do not cooperate with follow-up visits.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eInformed consent\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAnorectal physicians will obtain informed consent from the potential participants. Participants will be informed that they will be randomly allocated to either the Baliao acupuncture group or sham acupuncture group, and they will be made aware of the potential benefits and risks associated with the study. Participants will have the right to withdraw from the study at any time based on their own decision. Informed consent is available in Supplementary material 1.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSample size\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis is a superiority randomized controlled trial. The treatment group receives acupuncture and the control group receives sham acupuncture treatment. The allocation rate is 1:1. The primary outcome is the change from baseline in CSBMs per week. According to our pilot study, we assumed an effect size of 2.61 and a variance of 2.25. The superiority margin was set at 1.5 based on the minimal clinically important difference. 84 participants for each group (28 for each site), a total of 168 participants would be needed to provide 90% power to detect a superiority margin of 2 with a 2-sided \u0026alpha; of 0.05, allowing a 15% dropout rate. The sample size was calculated by PASS 2023 (NCSS, Kaysville, Utah, USA).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eRandomization and blinding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA computer-generated random allocation sequence will be generated by a research assistant. The participants will be assigned to the acupuncture group and the sham acupuncture group at a ratio of 1:1. The allocation sequence will be placed in opaque and sealed envelopes by the research assistant. The acupuncturist will open the envelope before the intervention. The participants, outcome assessors, and data analysts are blinded. The two groups have similar intervention locations, with the same duration and frequency of treatment. Participants are instructed to lie prone during the intervention and could not see the specific procedures, which also help prevent them from knowing their group allocation in advance.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eIntervention\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003ePhysicians will provide participants with a detailed explanation of the study background and procedures. Throughout the study, physicians will maintain regular communication with participants to respond to any questions or concerns.\u003c/p\u003e\n\u003cp\u003eIn both groups, participants without bowel movements for three or more consecutive days are allowed to use 110-220 mL glycerol enema (Beijing Maidihai Pharmaceutical Co., Ltd., Beijing, China) or lactulose oral solution 30mL (Abobott Biologicals B.V., OLST, The Netherlands) as a rescue intervention with documentation in the case report form (CRF). Other medications for constipation will not be permitted.\u003c/p\u003e\n\u003cp\u003eBaliao acupuncture group\u003c/p\u003e\n\u003cp\u003eParticipants in the Baliao acupuncture group will receive acupuncture at Baliao acupoints. Baliao acupoints are consist of Shangliao (BL31), Ciliao (BL32), Zhongliao (BL33), Xialiao (BL34) (Figure 2), Patients will be instructed to lie in prone position. After strict disinfection of the acupoint area, disposable acupuncture needles (Huatuo, Suzhou Medical Supplies Factory Co., Ltd., Suzhou, China) will be inserted into the Baliao acupoints for 3\u0026ndash;4 cm. Equal needle manipulations will be performed. The treatment will be administered five times per week, with each session lasting 30 min, for a total of four weeks. The specific operating steps are as follows:\u003c/p\u003e\n\u003cp\u003eFirst, locate acupoints. Locate the posterior midline of the sacrum and palpate the sacral depressions on both sides with your fingertips. The first to fourth pairs of sacral foramina are located in these depressions, which correspond to the Shangliao (BL31), Ciliao (BL32), Zhongliao (BL33), Xialiao (BL34) acupoints, respectively. When the fourth pair of sacral foramina is difficult to locate, acupuncture at Xialiao (BL34) should not be performed for safety considerations [30].\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eSecond, insert the needles. Acupuncture needles will be inserted into the first, second, third, and fourth pairs of sacral foramina, with a depth of 3\u0026ndash;4 cm according to the participants\u0026rsquo; body habitus.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThird, perform manipulations. When the needles are placed in the right position, participants will experience a needling sensation of soreness, numbness, distension, or heaviness. In this case, the acupuncturist will perform equal manipulations of twirling (both clockwise and anticlockwise), lifting, and thrusting (once every 10 min) to enhance and maintain the needling sensation [31].\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eSham acupuncture group\u003c/p\u003e\n\u003cp\u003eParticipants in sham acupuncture group will receive shallow needling at sham Baliao acupoints. Patients will be instructed to lie in prone position. After strict disinfection of the sham acupoint area, acupuncture needles (Huatuo, Suzhou Medical Supplies Factory Co., Ltd., Suzhou, China) will be inserted 5 mm away from the surface projections of the first, second, third, and fourth pairs of sacral foramina. Then, pinch the skin between the thumb and index finger. Insert the acupuncture needle at a 15-degree angle to the skin surface to a depth of 5 mm. Be careful not to penetrate the periosteum. Participants should not feel the needling sensation of soreness, numbness, distension, or heaviness. No manipulations of twirling, lifting, and thrusting will be performed. The treatment will be administered five times per week, with each session lasting 30 min, for a total of four weeks.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eOutcomes\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePrimary outcome\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe primary outcome is the change from baseline in complete spontaneous bowel movements (CSBMs) per week during treatment and follow-up period. CSBM is defined as a spontaneous bowel movement (SBM) associated with a sense of complete defecation. An SBM is a bowel movement that occurs without the use of laxatives, enemas, or other rescue interventions/assistance in the previous 24 hours.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSecondary outcomes\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe secondary outcomes are the change from baseline in SBMs per week during treatment and follow-up period, the change from baseline in patient assessment of constipation symptoms (PAC-SYM) scores and patient assessment of constipation quality of life questionnaire (PAC-QOL) scores at week 4 and week 8. PAC-SYM is an instrument used to evaluate the symptoms and severity of constipation. It consists of three parts: stool symptoms, rectal symptoms, and abdominal symptoms, with a total of 12 items. The score ranges from 0 to 48, with higher scores indicating more severe constipation symptoms. PAC-QOL is an instrument used to assess the impairment of constipation on patients\u0026rsquo; quality of life. It consists of four dimensions: physical discomfort, psychosocial discomfort, worry and discomfort, and treatment satisfaction, with 28 items. The score ranges from 0 to 112, with higher scores indicating a greater negative impact on quality of life [32-33].\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMechanism outcomes\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003efMRI\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eMRI scans will be conducted using a Siemens 3.0T Skyra MRI scanner (Siemens AG, Munich, Germany) at baseline period, week 4, and week 8. To minimize brain functional changes caused by discomfort in new environment, a separate empty scan will be performed for 30 seconds. Participants will be instructed to remain quiet, with their eyes closed and without performing any specific tasks in a supine position.\u003c/p\u003e\n\u003cp\u003eStructural Brain Imaging: T1-weighted imaging (T1WI) data is acquired using MPRAGE sequence. The scan parameters were as follows: TR = 15 ms, TE = 6.9 ms, flip angle = 15\u0026deg;, FOV = 256 mm \u0026times; 256 mm. A total of 196 sagittal slices were scanned with a slice thickness of 1 mm and no interslice gap.\u003c/p\u003e\n\u003cp\u003eResting-state fMRI: Resting-state fMRI data is acquired using blood oxygen level-dependent gradient echo-echo planar imaging (BOLD GRE-EPI) sequence. The scan parameters were as follows: TR/TE = 2000ms/30ms, flip angle = 90\u0026deg;, FOV = 240 mm \u0026times; 240 mm, matrix = 70 \u0026times; 70, slice thickness = 3.0 mm, no interslice gap, number of slices = 48. A total of 240 time points will be scanned, with a scan duration of 8 min.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAmplitude of Low-Frequency Fluctuations (ALFF), Regional Homogeneity (ReHo), and functional connectivity (FC) will be extracted from resting-state fMRI. ALFF measures the intensity of neuronal activity. The higher the value, the more active the neuronal activity. ReHo measures the consistency and synchronicity of neuronal activity. The higher the value, the more synchronized the neuronal activity. Functional connectivity refers to the temporal correlation between low-frequency blood oxygen level-dependent (BOLD) signals in different brain regions, reflecting the ability of these regions to work in coordination with each other [34].\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eHeart rate variability (HRV)\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eHRV signals will be collected at baseline period, week 4, and week 8 using a mobile electrocardiogram (ECG) recorder 8Z11 (Wegene Technology Inc., Shenyang, China). The participants need to hold the side pads of the ECG recorder with both hands and maintain a state of quietness, relaxation, and without performing any specific task for 5 min. After data collection is completed, the ECG data will automatically upload to the Wegene Technology ECG signal analysis system (Wegene Technology Inc., Shenyang, China) to calculate the standard deviation of normal-to-normal intervals (SDNN), root mean square of successive differences (RMSSD), proportion of adjacent RR intervals differing by more than 50 ms (pNN50), low-frequency component (LF), high-frequency component (HF), and LF/HF.\u003c/p\u003e\n\u003cp\u003eSDNN reflects the overall variability of HRV. RMSSD reflects the activity of the parasympathetic nervous system. pNN50 reflects the activity of the parasympathetic nervous system. LF reflects sympathetic nervous system activity. HF reflects parasympathetic nervous system activity. LF/HF reflects the balance between sympathetic and parasympathetic nervous system activities [35].\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePsychological outcomes\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003ePsychological outcomes are the changes from baseline in anxiety or depression proportion. Psychological assessment will be performed at baseline period, week 4 and week 8. The Zung self-rating anxiety Scale (SAS) and the Zung self-rating depression scale (SDS) will be used to assess the patients\u0026rsquo; anxiety and depression status. A standard score of \u0026ge;50 on the SAS and \u0026ge;53 on the SDS indicates anxiety and depression, respectively. Higher score indicates greater anxiety and depression. It should be noted that these scales measure the degree of anxiety and depression but should not be used as a diagnostic tool for anxiety or depressive disorders [36-37].\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSafety Evaluation\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study is associated with low to moderate risks. All adverse events will be documented, managed, and followed up until they are satisfactorily resolved, or the condition is stabilized. Anticipated adverse events include but are not limited to: Local infection, bleeding, hematoma, needle allergy, needle bending, dizziness, fatigue, fainting because of needling, electrolyte disturbances, cardiovascular adverse events caused by difficulty in defecation, and mechanical ileus caused by constipation. If a participant experienced dizziness, fatigue, or fainting caused by needling, the acupuncturist will stop needling immediately. Participants with mild or moderate adverse events will be treated by symptom. Severe adverse events will be managed proactively and reported to research ethics committee and data monitoring committee.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData collection,\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003emanagement and monitor\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eParticipants are required to record a stool diary to minimize recall bias. The stool diary can be recorded on a Wechat application named \u0026lsquo;poop diary\u0026rsquo; or a notebook for those who have difficulty using a digital device. We recommend participants record the diary at a fixed time every day in case of forgetting. Clinical data is collected using CRF by anorectal physicians. A research assistant will compile the data collected from the CRF and stool diary into an Excel spreadsheet, which will then be proofread by another research assistant. Anorectal physicians and research assistants will receive training on data collection standards. The data monitoring committee is composed of clinical experts, statisticians, and ethicists. It regularly reviews the study data to assess the risks and benefits of the study as well as the safety of the participants. All members are free from conflicts of interest and are not influenced by the study sponsor.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eStatistical Analysis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eClinical data analysis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe null hypothesis is that the change from baseline in mean CSBMs per week would be the same for the acupuncture group and the sham acupuncture group, and the alternative hypothesis is that the acupuncture group is superior to sham group. The superiority margin was set at 1.5 based on the minimal clinically important difference. The acupuncture group will be considered superior to the sham acupuncture group when the lower limit of the 95% confidence interval for the group difference exceeds the superiority margin. Analyses will be based on the intention-to-treat principle. Missing data will be filled by multiple imputation. Continuous variables that follow a normal distribution are presented as means \u0026plusmn; standard deviations (SD), while those that do not follow are presented as medians (interquartile ranges) (IQR). Categorical variables are presented as frequency (percentages). Comparisons between groups will be made using t-tests, Mann-Whitney U tests, or Chi-square tests, as appropriate. All statistical tests is 2-sided. P value of \u0026lt; 0.05 is considered significant.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMRI analysis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eDPABI\u003cstrong\u003e_\u003c/strong\u003eV9.0_250415 (http://rfmri.org/DPABI), a MATLAB toolbox, will be used to process and analysis brain imaging data. First, use DPARSF Advanced Edition (DPARSFA) module to pre-process data: remove first 10 time points, slice timing correction, head motion correction, spatial normalization, spatial smoothing, detrend. And then calculate ALFF/fALFF, ReHo. Second, use DPABI Statistical Analysis module to conduct t-tests for ALFF/fALFF and ReHo between pre- and post-treatment. Third, define regions of interest (ROI) based on the results and literature review, and then obtain FC using DPARSFA.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthical considerations\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eResearch ethical committee approval is obtained by The Ethics Committee of Guang\u0026rsquo;anmen Hospital, China Academy of Chinese Medical Sciences (approval number: 2025-KY-108). The research is registered in ClinicalTrials.gov (Identifier number: NCT07010367). During the research process, the personal privacy of participants and the confidentiality of data will be strictly protected. Personal information of participants will not be disclosed. The study findings will be published in accordance with academic standards.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eConstipation can pose negative impact on physical, social, and emotional well-being. Patient-reported outcomes are highly important when assessing therapeutic efficacy. Different populations may differ in descriptions of symptoms and reaction to stimulations [38-39], so we also need to introduce biomarkers to describe therapeutic efficacy objectively, especially regarding to explain mechanism. There are no widely recognized biomarkers for functional constipation that possess both high sensitivity and specificity. Most of them are experimental and lack of sufficient high-quality evidence in clinical practice.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eHRV and fMRI are promising biomarkers for functional constipation [40-41]. Gastrointestinal motility is regulated by the enteric nervous system (ENS), the autonomic nervous system (ANS), and the central nervous system (CNS) [42]. Heart rate variability is a non-invasive technique to monitor autonomic nervous system. The vagus nerve primarily exerts an inhibitory effect on the gastrointestinal tract, while the sympathetic nervous system inhibits gastrointestinal motility and secretory functions. Patients with functional bowel disorders often exhibit alterations in autonomic nervous system function [43]. fMRI is a non-invasive tool that allows mapping of human brain functions. It is reported that patients with functional constipation show significantly increased amplitude of low-frequency fluctuations (ALFF) in the right anterior insula, hippocampus, dorsal anterior cingulate cortex, and orbitofrontal cortex, while the ALFF in the precentral gyrus and supplementary motor area is significantly decreased [44]. Additionally, there is reduced functional connectivity between the thalamus and the parietal cortex [45]. This means that there are abnormalities in visceral activity and sensory processing in patients with functional constipation. Therefore, it is hypothesized that acupuncture at the Balian acupoints can modulate autonomic nervous activity and specific brain region activity to produce therapeutic effects on functional constipation.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eLimitation such as information bias should be noted in this study. No common consensus has been reached on how to design a control group in acupuncture study and sham acupuncture is a common choice in previous literature [46]. In this study, despite the two groups have a similar intervention area, the acupuncture needles in the sham group won\u0026rsquo;t insert as deep as the acupuncture group, and there are no needle manipulations in the sham group, thus participants will experience different needling sensation, especially for those who experienced acupuncture. There are possibilities that participants in the sham group might know which intervention they have received before unblinding. We will compare the proportions of participants who manage to know that they had received actual acupuncture between groups by a Chi-square test to examine whether the blinding is successful. Further research is needed to investigate its long-term efficacy, the utility of intermittent treatment, as well as the cost-effectiveness and cost-utility analysis of the treatment.\u003c/p\u003e"},{"header":"List of abbreviations","content":"\u003cp\u003eBL31, Shangliao\u003c/p\u003e\n\u003cp\u003eBL32, Ciliao\u003c/p\u003e\n\u003cp\u003eBL33, Zhongliao\u003c/p\u003e\n\u003cp\u003eBL34, Xialiao\u003c/p\u003e\n\u003cp\u003eBOLD, low-frequency blood oxygen level-dependent\u003c/p\u003e\n\u003cp\u003eCRF, case report form\u003c/p\u003e\n\u003cp\u003eCSBMs, complete spontaneous bowel movements\u003c/p\u003e\n\u003cp\u003efMRI, functional magnetic resonance imaging\u003c/p\u003e\n\u003cp\u003eHF, high-frequency component\u003c/p\u003e\n\u003cp\u003eHRV, heart rate variability\u003c/p\u003e\n\u003cp\u003eLF, low-frequency component\u003c/p\u003e\n\u003cp\u003ePAC-QoL, patient assessment of constipation quality of life\u003c/p\u003e\n\u003cp\u003ePAC-SYM, patient assessment of constipation symptoms\u003c/p\u003e\n\u003cp\u003epNN50, proportion of adjacent RR intervals differing by more than 50 ms\u003c/p\u003e\n\u003cp\u003eRMSSD, root mean square of successive differences\u003c/p\u003e\n\u003cp\u003eSDNN, standard deviation of normal-to-normal intervals\u003c/p\u003e\n\u003cp\u003eSDS, self-rating depression scale\u003c/p\u003e\n\u003cp\u003eSAS, self-rating anxiety scale\u003c/p\u003e\n\u003cp\u003eSBMs, spontaneous bowel movements\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eResearch ethical committee approval is obtained by The Ethics Committee of Guang\u0026rsquo;anmen Hospital, China Academy of Chinese Medical Sciences (approval number: 2025-KY-108). Participants recruitment is ongoing. Informed consent will be obtained from all participants.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eData are available from the corresponding author upon reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eFunding: This trial is supported by the Central Government\u0026rsquo;s Clinical Research Fund for High-Level TCM Hospitals (No. HLCMHPP2023131). The funding organization has no role in the study design, conduct, or decision-making for publication.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026apos; contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWei Chen designed the study and prepared the first draft of the manuscript, Qu muwen provided edits and critique. All authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eAlavi K, Thorsen AJ, Fang SH, et al. The American Society of Colon and Rectal Surgeons Clinical Practice Guidelines for the Evaluation and Management of Chronic Constipation. Dis Colon Rectum. 2024;67(10):1244-1257. doi:10.1097/DCR.0000000000003430\u003c/li\u003e\n \u003cli\u003eChang L, Chey WD, Imdad A, et al. 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Development and validation of the Patient Assessment of Constipation Quality of Life questionnaire. Scand J Gastroenterol. 2005;40(5):540-551. doi:10.1080/00365520510012208\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eCattarinussi G, Heidari-Foroozan M, Jafary H, et al. Resting-state functional magnetic resonance imaging alterations in first-degree relatives of individuals with bipolar disorder: A systematic review. J Affect Disord. 2024;365:321-331. doi:10.1016/j.jad.2024.08.040\u003c/li\u003e\n \u003cli\u003eOlivieri F, Biscetti L, Pimpini L, Pelliccioni G, Sabbatinelli J, Giunta S. Heart rate variability and autonomic nervous system imbalance: Potential biomarkers and detectable hallmarks of aging and inflammaging. Ageing Res Rev. 2024;101:102521. doi:10.1016/j.arr.2024.102521\u003c/li\u003e\n \u003cli\u003eZung WW. A self-rating depression scale. Arch Gen Psychiatry. 1965;12:63-70. doi:10.1001/archpsyc.1965.01720310065008\u003c/li\u003e\n \u003cli\u003eZung WW. A rating instrument for anxiety disorders. Psychosomatics. 1971;12(6):371-379. doi:10.1016/S0033-3182(71)71479-0\u003c/li\u003e\n \u003cli\u003eGerson CD, Gerson MJ, Awad RA, et al. Irritable bowel syndrome: an international study of symptoms in eight countries. Eur J Gastroenterol Hepatol. 2008;20(7):659-667. doi:10.1097/MEG.0b013e3282f53a24\u003c/li\u003e\n \u003cli\u003eTalley NJ, Weaver AL, Zinsmeister AR, Melton LJ 3rd. Functional constipation and outlet delay: a population-based study. Gastroenterology. 1993;105(3):781-790. doi:10.1016/0016-5085(93)90896-k\u003c/li\u003e\n \u003cli\u003eAli MK, Chen JDZ. Roles of Heart Rate Variability in Assessing Autonomic Nervous System in Functional Gastrointestinal Disorders: A Systematic Review. Diagnostics (Basel). 2023;13(2):293. doi:10.3390/diagnostics13020293\u003c/li\u003e\n \u003cli\u003eMayer EA, Naliboff BD, Craig AD. Neuroimaging of the brain-gut axis: from basic understanding to treatment of functional GI disorders.\u0026nbsp;Gastroenterology. 2006;131(6):1925-1942. doi:10.1053/j.gastro.2006.10.026\u003c/li\u003e\n \u003cli\u003eMargolis KG, Cryan JF, Mayer EA. The Microbiota-Gut-Brain Axis: From Motility to Mood. Gastroenterology. 2021;160(5):1486-1501. doi:10.1053/j.gastro.2020.10.066\u003c/li\u003e\n \u003cli\u003eLiu J, Lv C, Yin M, et al. Efficacy and safety of transcutaneous auricular vagus nerve stimulation in patients with constipation-predominant irritable bowel syndrome: a single-center, single-blind, randomized controlled trial. Am J Gastroenterol. 2024; doi:10.14309/ajg.0000000000003257\u003c/li\u003e\n \u003cli\u003eZhu Q, Cai W, Zheng J, et al. Distinct resting-state brain activity in patients with functional constipation.\u0026nbsp;Neurosci Lett. 2016;632:141-146. doi:10.1016/j.neulet.2016.08.042\u003c/li\u003e\n \u003cli\u003eMa PH, Yin T, He ZX, et al. Alterations of White Matter Network Properties in Patients With Functional Constipation. Front Neurol. 2021;12:627130. doi:10.3389/fneur.2021.627130\u003c/li\u003e\n \u003cli\u003eXiong Z, Ma P, Zhang H, et al. Placebo response to sham electroacupuncture in patients with chronic functional constipation: A secondary analysis. Neurogastroenterol Motil. 2024;36(5):e14770. doi:10.1111/nmo.14770\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003eTable 1 is available in the Supplementary Files section.\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-gastroenterology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bmge","sideBox":"Learn more about [BMC Gastroenterology](http://bmcgastroenterol.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/bmge/default.aspx","title":"BMC Gastroenterology","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Acupuncture, Functional constipation, Resting-state functional magnetic resonance imaging, Heart rate variability","lastPublishedDoi":"10.21203/rs.3.rs-7351160/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7351160/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground\u003c/strong\u003e Functional constipation lacks satisfactory and curative therapy. Acupuncture is a promising treatment while high-quality evidence is insufficient.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethod\u003c/strong\u003eThis is a multicenter, single-blind, superiority, parallel, randomized controlled trial. Participants diagnosed with functional constipation are allocated to treatment (Baliao acupuncture group) and control (sham-acupuncture group) groups at a 1:1 ratio. The randomization sequence is computer-generated. The primary outcome is the change from baseline in complete spontaneous bowel movements per week with a superiority margin of 1.5 to compare the Baliao acupuncture group and sham-acupuncture group. Resting-state functional magnetic resonance imaging and heart rate variability are used to investigate the therapeutic mechanisms. Statistical analysis is performed using an intention-to-treat analysis.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDiscussion\u003c/strong\u003e This study will partially illustrate that acupuncture at the Balian acupoints can modulate autonomic nervous activity and specific brain region activity to relieve functional constipation.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTrial registration\u003c/strong\u003e This trial is registered in ClinicalTrials.gov (Identifier number: NCT07010367, register date: 2025-06-07). Ethical approval was obtained from The Ethics Committee of Guang’anmen Hospital, China Academy of Chinese Medical Sciences (approval number: 2025-020-QS).\u003c/p\u003e","manuscriptTitle":"Effect of acupuncture at Baliao (BL31, BL32, BL33, BL34) on complete spontaneous bowel movements in functional constipation patients: study protocol for a randomized sham-controlled trial","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-05-12 14:15:04","doi":"10.21203/rs.3.rs-7351160/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"reviewersInvited","content":"","date":"2026-05-01T09:32:51+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-08-13T23:38:52+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-08-13T23:37:42+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Gastroenterology","date":"2025-08-12T04:12:48+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-gastroenterology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bmge","sideBox":"Learn more about [BMC Gastroenterology](http://bmcgastroenterol.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/bmge/default.aspx","title":"BMC Gastroenterology","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"57e34727-0af3-4836-a622-4b76fec3eb8e","owner":[],"postedDate":"May 12th, 2026","published":true,"recentEditorialEvents":[{"type":"reviewersInvited","content":"5","date":"2026-05-01T09:32:51+00:00","index":"","fulltext":""}],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-05-12T14:15:05+00:00","versionOfRecord":[],"versionCreatedAt":"2026-05-12 14:15:04","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7351160","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7351160","identity":"rs-7351160","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}