Combined Colon Hydrotherapy and Catgut Embedding at the Fujie (SP14) Acupoint for Treating Slow Transit Constipation: a clinical efficacy and safety study

Abstract

Objectives

Chronic idiopathic constipation, particularly slow transit constipation (STC), affects 2%-4% of the global population. It is characterized by impaired colonic transit and defecation difficulties. This study evaluated the safety and efficacy of combining colon hydrotherapy with catgut embedding at the Fujie (SP14) acupoint for treating STC.

Methods

In this single-center, randomized, open-label exploratory trial, 32 adult patients with STC were assigned to a combined group (colon hydrotherapy plus Fujie acupoint catgut embedding; n = 17) or a hydrotherapy group (colon hydrotherapy alone, n = 15). The primary outcome was the change from baseline in the total Patient Assessment of Constipation Symptoms (PAC-SYM) score at 4 weeks. Secondary outcomes included PAC-SYM subscale scores, post-treatment colonic transit marker retention, Patient Assessment of Constipation Quality of Life (PAC-QOL) scores, and safety outcomes.

Results

Both groups showed reductions in PAC-SYM scores after treatment. At 4 weeks, the combined group had a lower PAC-SYM total score than the hydrotherapy group (6.59 ± 2.96 vs. 8.81 ± 2.39, p = 0.028). The post-treatment Day-5 marker retention was significantly lower in the combined group than in the hydrotherapy group (4.35 ± 0.61 vs. 5.47 ± 1.13, p < 0.05), whereas the Day-3 between-group difference was not significant. PAC-QOL scores improved in both groups; greater improvements were observed in physical discomfort, psychosocial discomfort, and dissatisfaction in the combined group. However, because the Worries and Concerns domain differed at baseline, the results were interpreted cautiously. No serious adverse events were observed during the study.

Conclusion

Compared with hydrotherapy alone, combined colon hydrotherapy and Fujie acupoint catgut embedding improved constipation symptoms, selected quality-of-life domains, and post-treatment Day-5 colonic transit outcomes, with no major safety issues observed over the 4-week treatment period. However, larger registered trials with longer follow-up and baseline-adjusted analyses are required to confirm these findings.

INTRODUCTION

Chronic idiopathic constipation, a common form of functional constipation, affects approximately 14% of the global population [1]. Among its subtypes, slow transit constipation (STC) affects 2%-4% of individuals and is characterized by impaired colonic transit and reduced peristalsis [2, 3]. These pathophysiological changes result in prolonged fecal retention in the colon and difficulty with defecation [4-7]. Although the precise etiology of STC remains unclear, emerging evidence implicates hormonal and autoimmune dysregulation as contributing factors [6, 8, 9]. Changes in the gut microbiota may also influence susceptibility [10].

Colon hydrotherapy is a therapeutic modality that involves the use of specialized equipment to introduce warm, purified, mineralized water into the intestinal tract. This procedure helps remove fecal impactions, toxins, and other harmful substances while stimulating intestinal peristalsis to facilitate defecation [11]. It also modulates the intestinal microenvironment, restores gut microbiota equilibrium, and enhances digestion and absorption [12].

Traditional Chinese medicine (TCM) has shown notable efficacy in managing STC. For example, acupuncture is a widely used TCM approach, and acupoint catgut embedding has emerged as a promising therapy [13-15]. In particular, the Fujie (SP14) acupoint, located along the Spleen Meridian of the Foot-Taiyin, exerts therapeutic effects by invigorating the spleen and stomach, regulating qi flow, alleviating pain, and promoting intestinal motility. Catgut embedding at the Fujie acupoint aims to enhance meridian qi circulation, fortify splenogastric transportation, and improve colonic motility, thereby relieving constipation symptoms.

In this context, this exploratory study aimed to evaluate whether combining colon hydrotherapy with Fujie (SP14) acupoint catgut embedding could improve constipation symptoms, colonic transit outcomes, quality of life, and short-term safety in patients with STC compared with colon hydrotherapy alone.

MATERIALS AND METHODS

1. Study participants

A total of 32 adult patients (aged 18-65 years) with STC were prospectively enrolled at The People’s Hospital of Suzhou New District between April and October 2024. This study was approved by the Ethics Committee of Community Health Service Center of Suzhou Science & Technology Town (approval number: E20240711) and adhered to the principles of the Declaration of Helsinki. All participants provided written informed consent before enrollment. Eligibility criteria were as follows: (1) patients diagnosed with STC based on Rome IV criteria [16]; (2) those with fewer than three spontaneous bowel movements per week on average over the past 3 months; (3) those with associated symptoms such as defecation difficulty and hard stools; (4) those with colonic transit dysfunction confirmed via colonic transit testing; and (5) those who provided written informed consent. Exclusion criteria were as follows: (1) patients with organic intestinal diseases, such as tumors, inflammatory bowel disease, or intestinal obstruction; (2) those with severe cardiohepatorenal dysfunction; (3) those who are pregnant or lactating; (4) those with catgut allergy; and (5) those receiving other constipation treatments such as surgery, acupuncture, or TCM within the past month.

2. Randomization and blinding

Eligible participants were randomly assigned to either the combined group or the hydrotherapy group in a 1:1 ratio using a computer-generated simple random sequence generated before enrollment. No block or stratified randomization was employed. Allocation concealment was ensured with sequentially numbered, opaque, sealed envelopes prepared by personnel not involved in treatment or outcome assessment. After confirming eligibility, a study coordinator opened the next envelope in sequence. Because of the procedural nature of the interventions, neither the participants nor the treating clinicians could be blinded; however, outcome assessors and statistical personnel were blinded to group allocation whenever feasible. The open-label design was considered a potential source of performance bias and is acknowledged as a study limitation.

3. Interventions

Patients were divided into two groups: the hydrotherapy group received colon hydrotherapy alone, whereas the combined group received colon hydrotherapy plus Fujie (SP14) acupoint catgut embedding.

The colon hydrotherapy protocol was identical in both groups, and a Xiongfei CTJ-A colon hydrotherapy device (serial number XF200820A) was used. Patients were positioned in the left lateral decubitus with knees flexed. A lubricated disposable anal tube was inserted 10-15 cm into the rectum and secured. Treatment parameters were water temperature of 39℃-41℃ and a flow rate of 150 mL/min. During hydrotherapy, abdominal massage was performed in the ascending, transverse, and descending colon sequence to augment peristalsis. Each session lasted 30-40 min and was administered weekly for four consecutive weeks.

Patients in the combined group underwent Fujie acupoint catgut embedding according to the protocol. Patients were placed in a supine position, and the Fujie (SP14) acupoint was identified using the finger-based measurement technique. Following local disinfection, a 1-cm absorbable surgical suture was inserted into a catgut-embedding needle. The needle was rapidly inserted into the acupoint, and the suture was implanted by advancing the needle core, after which the needle was promptly withdrawn. This procedure was repeated at 2-week intervals for a total of two sessions.

4. Efficacy indicators

1) Primary outcome

The change in total PAC-SYM scores from baseline at 4 weeks was the primary efficacy outcome. This scale evaluates abdominal, rectal, and stool symptoms, with each item scored from 0 to 4; higher scores indicate more severe symptoms.

2) Secondary outcomes

Secondary efficacy outcomes included PAC-SYM subscale scores at 1 and 4 weeks, post-treatment colonic transit outcomes, and PAC-QOL scores. For the colonic transit test, patients ingested a capsule containing 20 radiopaque markers, and abdominal X-rays were obtained on days 3 and 5 after ingestion. Retention of > 80% of markers on day 3 or ≥ 5 markers on day 5 indicated impaired colonic transit. Enrollment required baseline colonic transit dysfunction, and post-treatment marker retention was used to assess residual dysfunction between groups.

3) Quality-of-life assessment

Quality of life was evaluated using the PAC-QOL scale, a 28-item questionnaire assessing physical and psychosocial discomfort, worries and concerns, and dissatisfaction, with higher scores indicating poorer quality of life.

5. Safety indicators

Adverse events, including abdominal pain, bloating, diarrhea, tenesmus, intestinal perforation, infection, and bleeding, were closely monitored. Laboratory assessments before and after treatment including routine blood, urine, and stool analyses; liver and kidney function evaluations; and coagulation profiles were performed to evaluate treatment safety.

6. Sample size

This was an exploratory, single-center clinical study. No formal a priori sample size or power calculation was performed; the number of participants was determined by feasibility during the study period. Because no expected effect size, statistical power, or sample size assumptions were prespecified, this study should be considered hypothesis-generating rather than providing definitive conclusions on safety or efficacy.

7. Data collection and statistical analysis

PAC-SYM data were collected at baseline, 1 week, and 4 weeks. PAC-QOL was assessed at baseline and follow-up. Colonic transit was assessed via radiopaque marker retention on days 3 and 5 after treatment. Statistical analyses were performed using SPSS 22.0, with statistical significance set at p < 0.05. Continuous variables are expressed as means ± standard deviations. Considering the small sample size and ordinal nature of PAC-SYM and PAC-QOL items, within-group comparisons were performed using the Wilcoxon signed-rank test, whereas between-group comparisons were performed using the Wilcoxon rank-sum test. For baseline continuous variables with a normal distribution, independent-samples t-tests were used. Categorical variables are presented as counts and percentages and were analyzed using the chi-square test or Fisher’s exact test, as appropriate. Because this was an exploratory study with multiple secondary outcomes, no correction for multiple comparisons was applied; secondary and subscale analyses are interpreted as supportive. Because the PAC-QOL Worries and Concerns domain exhibited baseline imbalance, follow-up comparisons were interpreted cautiously and considered along with changes from baseline.

RESULTS

1. General characteristics

In total, 32 participants were enrolled, with 17 and 15 assigned to the combined and hydrotherapy groups, respectively. No participants withdrew during the 4-week study period; thus, all randomized participants were included in the analysis. Fig. 1 shows a CONSORT-style participant flow diagram. Baseline characteristics including mean age, body weight, body mass index, height, and disease duration did not differ significantly between the two groups (Table 1).

Figure 1.

CONSORT-style participant flow diagram summarizing enrollment, randomization, follow-up, and analysis.

Table 1.

Baseline characteristics of enrolled patients

	Combined group	Hydrotherapy group	p-value
Sex (male/female)	10/7	12/3	0.265
Age (years)	51.24 ± 11.459	50.40 ± 12.141	0.657
Weight (kg)	63.835 ± 16.070	63.093 ± 13.267	0.311
Height (cm)	166.94 ± 11.127	169.133 ± 8.576	0.165
BMI (kg/m2)	22.518 ± 3.073	23.920 ± 2.690	0.239
Duration (years)	10.529 ± 3.204	10.267 ± 2.685	0.937

BMI, body mass index.

2. Constipation symptom scores

Before treatment, PAC-SYM total and subscale scores were comparable between the groups (p > 0.05). After treatment, both groups showed reduced PAC-SYM scores (p < 0.05 for within-group comparisons). Mean total PAC-SYM score changes from baseline at 4 weeks were –8.35 and –5.32 points in the combined and hydrotherapy groups, respectively. At 4 weeks, the combined group had a lower total PAC-SYM score than the hydrotherapy group (6.59 ± 2.96 vs. 8.81 ± 2.39; the mean difference was –2.21 (95% confidence interval: –4.17 to –0.25; p = 0.028), and supportive improvements in the abdominal, rectal, and stool-related symptom domains were observed (Table 2, Fig. 2). This exploratory trial assessed multiple symptom domains; thus, subscale findings are interpreted as supportive rather than confirmatory.

Table 2.

Constipation symptoms

Item		Combined group				Hydrotherapy group
		Baseline	1 week	4 weeks		Baseline	1 week	4 weeks
Abdominal symptoms	1. Abdominal discomfort	1.06 ± 0.56	0.41 ± 0.51*	0.47 ± 0.51*		1.07 ± 0.59	0.60 ± 0.63*	0.73 ± 0.59*
	2. Abdominal pain	0.82 ± 0.64	0.47 ± 0.51*	0.47 ± 0.51*		0.93 ± 0.70	0.60 ± 0.63	0.53 ± 0.52*
	3. Abdominal bloating	1.06 ± 0.66	0.59 ± 0.51*	0.65 ± 0.49*		0.93 ± 0.26	0.73 ± 0.46	0.73 ± 0.46
	4. Stomach cramps	0.71 ± 0.47	0.35 ± 0.49*	0.41 ± 0.51*		0.67 ± 0.49	0.47 ± 0.52	0.40 ± 0.51*
	Total scores	3.65 ± 1.37	1.82 ± 1.24	2 ± 1.17		3.6 ± 1.06	2.4 ± 0.83	2.41 ± 0.82
Rectal symptoms	5. Painful bowel movement	0.88 ± 0.70	0.47 ± 0.51*	0.47 ± 0.51*		0.93 ± 0.46	0.47 ± 0.52*	0.47 ± 0.52*
	6. Rectal burning	1.24 ± 0.66	0.47 ± 0.62*	0.41 ± 0.62*		1.13 ± 0.64	0.53 ± 0.52*	0.67 ± 0.62*
	7. Rectal tearing/bleeding	1.29 ± 0.47	0.41 ± 0.51*	0.35 ± 0.49*		1.27 ± 0.70	0.67 ± 0.62*	0.60 ± 0.51*
	Total scores	3.41 ± 1.28	1.35 ± 1.17	1.24 ± 1.09		3.33 ± 1.59	1.67 ± 1.35	1.73 ± 1.33
Stool symptoms	8. Incomplete defecation	1.35 ± 0.49	0.59 ± 0.51*	0.53 ± 0.51*		1.20 ± 0.68	0.80 ± 0.68*	1.07 ± 0.88
	9. Hard stools	1.47 ± 0.51	0.76 ± 0.56*	0.71 ± 0.47*		1.53 ± 0.74	0.93 ± 0.70*	0.80 ± 0.56*
	10. Small-sized stools	1.59 ± 0.62	0.88 ± 0.60*	0.76 ± 0.44*		1.60 ± 0.63	0.93 ± 0.59*	0.93 ± 0.70*
	11. Straining during defecation	1.94 ± 0.75	0.76 ± 0.66*	0.88 ± 0.78*		1.53 ± 0.64	0.80 ± 0.56*	0.93 ± 0.59*
	12. Urge incontinence	1.53 ± 0.62	0.53 ± 0.51*	0.47 ± 0.51*		1.33 ± 0.49	0.67 ± 0.49*	0.93 ± 0.59*
	Total scores	7.88 ± 2.42	3.53 ± 2.29	3.35 ± 2.12		7.2 ± 2.21	4.13 ± 1.77	4.67 ± 1.88
Total scores		14.94 ± 3.38	6.71 ± 3.08	6.59 ± 2.96&		14.13 ± 3.83	8.2 ± 2.08	8.81 ± 2.39

^*p < 0.05 for comparisons with baseline values in either group using the Wilcoxon signed-rank test; ^&p < 0.05 for the primary between-group comparison of PAC-SYM total score at 4 weeks using the Wilcoxon rank-sum test.

Figure 2.

Constipation symptoms. (A) Abdominal symptoms between groups and visits. (B) Rectal symptoms between groups and visits. (C) Stool symptoms between groups and visits. (D) Total scores between groups and visits.

3. Colonic transit test

Table 3 summarizes the post-treatment colonic transit outcomes. On day 5, the number of retained radiopaque markers was lower in the combined group than in the hydrotherapy group (4.35 ± 0.61 vs. 5.47 ± 1.13, p = 0.004), whereas no significant difference was observed on day 3 (15.18 ± 1.24 vs. 15.87 ± 1.36, p = 0.156). The numbers of patients meeting the predefined dysfunction criteria were 6 and 9 on Days 3 and 5 and 11 on Day 5 in the combined and hydrotherapy groups, respectively. Numerical baseline marker counts were unavailable in the final dataset; therefore, change-from-baseline colonic transit analyses were not performed, and the post-treatment colonic transit findings should be interpreted cautiously.

Table 3.

Post-treatment colonic transit outcomes

	Day 3 post-treatment			Day 5 post-treatment
	Retained markers, n	Residual dysfunction, n (%)		Retained markers, n	Residual dysfunction, n (%)
Combined group	15.18 ± 1.237	6 (35.3)		4.35 ± 0.606	5 (29.4)
Hydrotherapy group	15.87 ± 1.356	9 (60.0)		5.47 ± 1.125&	11 (73.3)

Markers indicate the number of radiopaque markers retained after treatment. Residual dysfunction: retention of > 80% of markers on day 3 or ≥ 5 markers on day 5. ^&p = 0.004 for the between-group comparison at day 5 using the Wilcoxon rank-sum test. Day-3 between-group comparison was not significant (p = 0.156).

4. Quality-of-life assessment

No significant intergroup differences were observed in most PAC-QOL domains before treatment; however, the Worries and Concerns domain differed significantly at baseline. After treatment, PAC-QOL scores improved in both groups (p < 0.001 for within-group comparisons). Follow-up scores for physical discomfort, psychosocial discomfort, and dissatisfaction were significantly lower in the combined group than in the hydrotherapy group (p < 0.001 for the three comparisons), suggesting greater improvement in these domains (Table 4, Fig. 3). For the Worries and Concerns domain, the mean changes from baseline were –4.76 and –6.73 in the combined and hydrotherapy groups, respectively. Because the baseline value was higher in the hydrotherapy group and the descriptive change numerically favored this group, this domain was not interpreted as evidence of superiority of the combined treatment.

Table 4.

Assessment of constipation by quality of life

Item	Combined group			Hydrotherapy group
	Baseline	Follow-up		Baseline	Follow-up
Physical discomfort	11.76 ± 0.831	4.94 ± 1.088*		11.33 ± 1.291	8.4 ± 1.298*,&
Psychosocial discomfort	26 ± 1.414	15.94 ± 1.435*		25.93 ± 1.387	19.93 ± 1.223*,&
Worries and concerns	19 ± 1.414	14.24 ± 1.602*		20.13 ± 1.642$	13.4 ± 1.595*
Dissatisfaction	15.18 ± 1.667	6.35 ± 1.222*		15.07 ± 1.28	8.47 ± 1.06*,&

^*p < 0.001 for comparisons with baseline values in either group using the Wilcoxon signed-rank test. ^&p < 0.05 for between-group comparisons at follow-up using the Wilcoxon rank-sum test. ^$p < 0.05 for between-group baseline differences using the Wilcoxon rank-sum test.

Figure 3.

PAC-QOL scores. (A) Physical discomfort score. (B) Psychosocial discomfort score. (C) Worries and Concerns score. (D) Dissatisfaction score.

5. Adverse events

During the treatment period, adverse events were mild and transient. In the combined group, four patients (23.5%) reported adverse events, including two cases of abdominal pain, one case of diarrhea, and one case of dry mouth. In the hydrotherapy group, six patients (40.0%) reported adverse events, including three cases of abdominal pain, two cases of abdominal distension, and one case of anal tenesmus (Table 5). All events resolved spontaneously within 1-2 days without intervention. No intestinal perforation, severe bleeding, infection, or other serious adverse events were observed. Routine laboratory tests including blood, urine, and stool analyses; liver and kidney function assessments; and coagulation profiles revealed no clinically meaningful changes in either group. Additionally, the incidence of adverse events did not differ significantly between groups (p = 0.45).

Table 5.

Adverse events

	Combined group, n (%)	Hydrotherapy group, n (%)
Adverse events	4 (23.5)	6 (40.0)
Abdominal pain	2 (11.8)	3 (20.0)
Abdominal distension	0 (0)	2 (13.3)
Diarrhea	1 (5.9)	0 (0)
Anal tenesmus	0 (0)	1 (6.7)
Dry mouth	1 (5.9)	0 (0)

No serious adverse events were observed. p = 0.450 for the between-group comparison of overall adverse-event incidence.

DISCUSSION

This exploratory randomized study suggests that colon hydrotherapy combined with catgut embedding at the Fujie (SP14) acupoint may provide additional benefits over colon hydrotherapy alone for patients with STC. The combined treatment showed greater improvements in total PAC-SYM scores at 4 weeks, reduced Day-5 post-treatment radiopaque marker retention, and improvements in selected PAC-QOL domains. Although these findings support a potential role for this combined nonpharmacological approach, they should be considered preliminary because of the small sample size, short follow-up, and exploratory statistical design.

Colon hydrotherapy may provide short-term symptom relief by softening and removing the retained fecal material, reducing the rectocolonic load, and stimulating intestinal peristalsis [17]. Catgut embedding at SP14 provides prolonged acupoint stimulation, potentially regulating gastrointestinal motility through neurohumoral and local reflex pathways [18]. Therefore, the observed benefit of the combined approach may reflect complementary short-term mechanical effects and sustained acupoint stimulation. However, this study did not directly measure mechanistic biomarkers; thus, all mechanistic explanations should be considered hypothesis-generating.

Gut microbiota may be involved in chronic constipation and gastrointestinal motility regulation. Although previous studies have explored microbiome-related changes in gastrointestinal disorders and experimental models [19, 20], the present study did not assess microbiome composition; therefore, it cannot establish whether microbiota modulation influenced the observed clinical effects. Future research should incorporate fecal microbiome and metabolomic analyses to explore potential microbiota-related mechanisms.

No major safety concerns were observed during the 4-week treatment. Adverse events were mild and self-limited, and routine laboratory parameters remained clinically stable. Nevertheless, the study was underpowered to detect uncommon, delayed, or serious adverse events. Therefore, larger studies with longer follow-up are needed before drawing definitive safety conclusions.

Compared with long-term pharmacotherapy, this nonpharmacological approach may reduce concerns regarding medication dependence, electrolyte disturbance, and drug-related gastrointestinal adverse effects [21]. Compared with surgery, this approach is minimally invasive and may appeal to nonsurgical candidates or those who prefer conservative management [22]. However, the current study did not directly assess comparative advantages, which require confirmation in future trials.

This study has several limitations. First, the sample size was small, and no formal a priori power calculation was performed; therefore, the study may be underpowered and vulnerable to selection bias. Second, the trial was open-label, with participants and treating clinicians unblinded, which may have introduced performance bias. Third, although baseline colonic transit dysfunction was required for enrollment, numerical baseline radiopaque marker counts were not provided, limiting assessments of pretreatment comparability and change from baseline. Fourth, the PAC-QOL Worries and Concerns domain differed between groups at baseline; thus, the interpretation of this domain remains limited. Fifth, the short follow-up period precluded the assessment of long-term efficacy, relapse rates, and delayed adverse events. Sixth, lifestyle factors such as diet, fluid intake, and exercise were not strictly controlled. Future multicenter, registered, sufficiently powered trials should incorporate concealed randomization, blinded outcome assessment, baseline-adjusted or mixed-effects analyses, exact p-values, confidence intervals, effect size estimates, and longer follow-up.

CONCLUSION

This small exploratory study showed that combining colon hydrotherapy with Fujie (SP14) acupoint catgut embedding resulted in greater improvements in constipation symptoms, selected quality-of-life domains, and Day-5 post-treatment colonic transit outcomes than colon hydrotherapy alone. No major safety concerns were observed during the 4-week treatment. However, these preliminary findings require confirmation in larger, prospectively registered, baseline-adjusted, randomized controlled trials with longer follow-up.