A randomized, controlled clinical trial of acupoint catgut embedding as an effective control of functional anorectal pain

Abstract

Background:

Patients with functional anorectal pain (FAP) usually feel pain in the anal region, foreign body sensation, and defecation disorders. The pain may radiate to the perineum, thighs, and waist. Conventional biofeedback, local nerve block and surgical treatment have certain limitations. Thread-embedding acupuncture (TEA) is a complementary and alternative therapy, which is widely used in the clinical practice of traditional Chinese medicine to treat functional anorectal pain. This study evaluated the efficacy and safety of the catgut-embedding acupuncture in patients with FAP.

Methods:

FAP patients were enrolled and randomly divided into a thread-embedding acupuncture group (n = 35) and a sham-embedding acupuncture control group (n = 36). Patients underwent treatment twice monthly for 2 months and were assessed before and after treatments for visual analogue scales (VAS) of anorectal pain, VAS of lumbar pain or soreness, VAS of abdominal distension or pain, anal incontinence index, and SF-36 quality of life. The SF-36 quality of life score included assessment of physical functioning, role-physical, bodily-pain, general health, role-emotional, social functioning, vitality, and mental health.

Result:

The total effective rate was 85.71% for the treatment group versus 8.33% of the controls after 2 months (P < .001). The patients’ anal rectum VAS score was significantly higher after treatment versus pretreatment (P < .01), while the physical functioning, role-physical, bodily-pain, role-emotional, and mental health in the experimental group and the role-emotional, and mental health in the control group were all significantly improved versus pretreatment (P < .05). The anorectal VAS score, anal incontinence index, and the SF-36 scores of the physical functioning, role-physical, bodily-pain, role-emotional, and mental health were better in the treatment group compared to the control group (P < .05). Most importantly, there were no adverse reactions observed in either group during the treatment.

Conclusion:

The thread-embedding acupuncture treatment effectively and safely improved the emotional anxiety and quality of life in FAP patients.

1. Introduction

Functional anorectal pain (FAP) is a diverse group of syndromes that affect the quality of life of patients.^[1] Clinically, FAP can be divided into 3 types: levator ani syndrome, proctalgia fugax, and unspecified FAP. These are distinguished according to the duration of pain and the presence or absence of anorectal tenderness, although there is significant overlap among them clinically.^[2,3] Levator ani syndrome has previously been speculated to result from pelvic floor muscle spasms and elevated anal resting pressures,^[2] while other studies have speculated that rectoanal incoordination may be a pathophysiological explanation for levator ani syndrome.^[4] In contrast, proctalgia fugax refers to sudden severe pain in the rectal area, which continues for a few seconds to minutes, but rarely up to 30 minutes, and completely disappears thereafter.^[5] Approximately 10% of the adult population in the USA, Canada, and the UK had “Rome IV functional dyspepsia” with considerable association with health impairment,^[6] indicating that a high incidence rate of FAP in these populations as a common but difficult to control syndrome, which leads to anal pain and defecation disorders.^[7] Clinically, physicians may have some difficulty firmly diagnosing FAP because it is a functional disorder with special pain localization and the mutual influences of adjacent organs.^[8] Differential diagnosis excludes any definite organic lesions or special pathological changes.^[9] To date, the etiology and pathogenesis of FAP still remain to be defined although Western medicine has provided information on the diagnostic criteria, pathophysiology, and management of common anorectal disorders, including FAP.^[3] From the perspective of traditional Chinese medicine (TCM), the etiology and pathogenesis of FAP may be due to an imbalance of cold and heat producing dampness and heat, phlegm and dampness, and emotional stimulation. To date, the treatment of FAP, especially levator ani syndrome, is primarily supportive and includes drug therapy, biofeedback, and sacral nerve stimulation, while treatment of proctalgia fugax is often impractical since the duration of symptoms is so short.^[3] In China, FAP could be treated with TCM techniques such as acupuncture. Indeed, Chinese researchers have made considerable achievements in the neurobiology of acupuncture analgesia.^[10] For example, in patients with FAP or with similar pain symptoms caused by pelvic floor muscle dysfunction and nervous disorders,^[11] acupuncture has shown remarkable advantages in symptom reduction. Unfortunately, acupuncture treatments often require patients to visit a clinic daily. Thus, thread-embedding acupuncture (TEA) has been developed as a novel type of long acting acupuncture stimulation therapy^[12,13] and has successfully treated many anorectal disorders, like post-surgery pain, urinary retention, anal swelling, constipation, and abdominal distention.^[13]

Our previous study compared the effectiveness of TEA in combination with TCM versus TCM-only in the control of FAP.^[14] We found that the combined TEA had a more significant effect than TCM alone.^[14] Thus, in this study, we designed a randomized controlled clinical trial to further assess the therapeutic effect of TEA versus sham operation on control of FAP. We expect to provide useful information for future clinical control of this currently difficult-to-manage syndrome.

2. Materials and methods

2.1. Study subjects

This study enrolled a total of 71 FAP patients from Nanjing Hospital of Traditional Chinese Medicine, Nanjing University of Traditional Chinese Medicine (Nanjing, China) between May 2019 and December 2021. Patients were recruited using WeChat, posters, and other means of publicity. All patients participated in the clinical trial on a voluntary basis. The ethics committee of Nanjing Hospital of Traditional Chinese Medicine approved the study (ky2018022) and is registered at the Chinese Registry of Clinical Trials (ChiCTR1800019033).

2.2. Diagnosis, inclusion, exclusion criteria

FAP patients were diagnosed using both Western medicine and TCM criteria. We first utilized the Rome IV diagnostic standard of functional gastrointestinal diseases^[15–17] for nonspecific FAP using the following criteria: (1) chronic or recurrent anorectal pain, (2) pain lasting for at least 30 minutes, (3) no tenderness when the puborectal muscle was pulled from the rear, and (4) exclusion of other causes of anorectal pain (i.e., ischemia, organic lesions, inflammatory diseases, muscle damage, and coccygeal pain). The aforementioned symptoms occurred at least 6 months prior and lasted for at least 3 months. The TCM diagnostic criteria for FAP included anorectal distention or tingling, particularly in the night, and involved the abdominal, external genitalia, and sacrum without any known organ diseases.^[18]

The inclusion criteria of patients for this clinical trial were: (1) diagnosed with FAP using Western medicine criteria, (2) diagnosed with FAP using TCM criteria, (3) between 18 and 70 years old, (4) no other related treatments, and (5) willingness to take tests and give informed consent. The exclusion criteria were: (1) patients who did not satisfy the FAP diagnostic criteria, (2) pregnant, lactating, and menstruating women, (3) patients with poor heart, liver, kidney, and hematopoietic functions, (4) patients with a medical history of allergic reactions, (5) psychotic patients who were unable to cooperate or in whom it would be difficult to accurately evaluate the effectiveness and safety of the therapy, and (6) patients who did not commit to the study or would not provide informed consent.

2.3. Treatment procedures

Enrolled patients were randomly assigned into the thread-embedding acupuncture (TEA) or the sham-embedding acupuncture (SEA) groups using a computer-generated randomized table. The eligibilities of FAP patients were independently assessed by a physician and patients were treated by an experienced acupuncturist. The patients and assessors were blinded to the treatment groups, while the acupuncturists who treated patients were excluded from evaluation and assessment of patients or data entry. A statistician independently analyzed the data (Fig. 1).

Figure 1.

Illustration of study design and procedures.

Prior to treatment, TEA patients were instructed to lie in a prone position on the treatment bed and then operated on by an experienced acupuncturist. Patients then rested for 5 to 10 minutes, then turned over and were placed in the supine position to operate on the front acupoints. Point localizations were GV1 (Changqiang), BL20 (Pishu), BL21 (Weishu), BL23 (Shenshu), BL34 (Xialiao), BL35 (Huiyang), BL57 (Chengshan), DU20 (Baihui), RN12 (Zhongwan), CV4 (Guanyuan), CV6 (Qihai), GB26 (Daimai), and ST36 (Zusanli). Selected acupoints were marked with a marker. Patients were disinfected using an iodine alcohol solution, anesthetized using local lidocaine ointment half an hour before embedding the suture, and then disinfected with iodine. The operator used 1 to 1.5 cm of the 4-0 absorbable synthetic suture (Covidien synthetic absorbable surgical suture GL-181 purple 4-0; see Fig. S1, Supplemental Digital Content, http://links.lww.com/MD/K181, which demonstrates the model of disposable sterile syringe) to insert it into the tip of a 2 ml disposable sterile syringe (Shandong Weigao Group Medical Polymer Products Co., Shandong, China; see Fig. S2, Supplemental Digital Content, http://links.lww.com/MD/K182, which demonstrates the model of synthetic absorbable surgical suture). Next, they utilized wrist force to pierce the needle under the skin for 2 to 3 cm, bury the suture, and then withdraw the needle back under the skin. After that, lifting, inserting, and twirling techniques were applied to obtain acupuncture virtue. After the needle was withdrawn, a sterile dry cotton ball was used to briefly apply pressure to the needle prick to prevent bleeding, and a bandage was used to cover the prick to prevent infection. SEA patients underwent a similar procedure but without the embedding of the thread-body. This operation was repeated every 2 weeks for 2 months. Patients were evaluated before and after each procedure. Patients were monitored for adverse reactions associated with acupoint thread embedding, such as local or subcutaneous bleeding, syncope, severe pain, and local infection.

2.4. Evaluation and outcome measurements

Before and after treatment, patients were evaluated for visual analogue scales (VAS) (a 11-point rating scale with a score range of 0–10, while the 10 was the worst score) to measure pain intensity. The anal incontinence index was also utilized using the following grading system: normal (0 points), grade 1: occasional feces with mucous in underwear or loose stools (1 point), grade 2: frequent feces or feces on the underwear as grade (2 points), and grade 3: unable to control soft or liquid stool, but can control solid, semisolid stool (3 points). Furthermore, the SF-36 quality of life score^[19] that includes measures of physical functioning, role-physical, bodily-pain, general health, role-emotional, social functioning, vitality, and mental health, was also used to evaluate both the physical and psychological well-being of patients. In addition, the therapeutic effect of treatment on patients was evaluated by calculating the intensity of the anorectal pain using the VAS evaluation weighting method (VAS value before treatment − VAS score after treatment/VAS value before treatment).

The outcome of treatment was assessed according to the curative effect index as: 100%, significant effect, 70% of the curative effect index < 100%, effective as 30% < the curative effect index but <70%, ineffective as the efficacy index < 30%. The efficacy index (%) = (VAS score before treatment − VAS score after treatment)/VAS score before treatment × 100%. Possible adverse reactions related to the treatment were recorded within 2 weeks after each treatment and within 1 week at the end of the 2 months of treatment.

2.5. Statistical analysis

The study adopts a completely randomized design. The sample size was calculated based on the sample size calculation formula:

$${\displaystyle \begin{array}{l}{\displaystyle n=\frac{2{(z_{\alpha }+z_{\beta })}^2\ast {\sigma }^2}{{\delta }^2}}\end{array}}$$

where α is the type I error, 1-β is the degree of grasp, σ is the standard deviation, δ is the difference between the means of the 2 groups, and n is the sample size. According to the results of previous studies, α = 0.05, 1-β = 0.9 were set. The sample size is estimated to be 54 cases. A total of at least 68 subjects were included, considering 20% loss to follow-up and refusal to visit.

All statistical analyses were performed using SPSS 25.0 (SPSS, Chicago, IL). The differences between the TEA and SEA groups were analyzed using the independent sample t-test, a non-parametric test, or Fisher exact test for enumeration data, while the rank sum test was used for ranking data, the Wilcoxon rank sum test or the Wilcoxon signed-rank test. The pairwise t-test or non-parametric test was performed for intra-group comparisons the non-parametric test was for enumeration data. We conducted 13 statistical analyses to assess the VAS, the SF-36 quality of life scores (including 8 dimensions), the anal incontinence index, and the clinical effective rate of 2 groups. In order to reduce Type I errors, we adjusted the P-values by multiplying them by 13. P < .05 was considered statistically significant.

3. Results

3.1. Patient characteristics

A total of 71 FAP patients were enrolled and randomly divided into the experimental group (n = 35, 7 males [20%] and 28 females [80%]), and control group (n = 36, 14 males [38.9%] and 22 females [61.1%]). The average age of these patients was 54.1 years old and 70.4% of the patients were female. There was no statistically significant difference in gender, age, and disease course between the 2 groups (P > .05; Table 1; see Table S1, Supplemental Digital Content, http://links.lww.com/MD/K176, which shows the degrees of freedom, t-value, Z value, chi-square value, etc).

Table 1.

Characteristics of patients in the experimental and control groups.

Demographic characteristics	Thread-embedding acupuncture (n = 35)	Sham-embedding acupuncture (n = 36)	Statistics	P value
Gender, n (%)
Male	7 (20.0)	14 (38.9)	No value	0.081
Female	28 (80.0)	22 (61.1)
Age (year), M(SD)	55.3 ± 9.6	52.9 ± 10.2	t = 1.017	0.312
Course of disease (months), M(P25, P75)	25.0 (16.0, 39.0)	33.0 (20.5, 49.5)	Z = 1.330	0.184

3.2. Primary and secondary treatment outcomes

In terms of the VAS score, there was no statistically significant difference in the anorectal VAS score, abdominal distension and abdominal pain VAS score, and lumbar pain or soreness VAS score between the 2 groups of patients at pretreatment (P > .05). However, there was a statistical difference in the anorectal VAS score (P-adjust < .013) and the average score in the acupoint embedding group compared to the sham embedding group (2.73 folds higher), although there was no significant difference in the VAS score of abdominal distension and abdominal pain, lumbar pain, and lumbar acid between the 2 groups of patients after treatment (P-adjust = 1.000). After treatment, the anorectal VAS scores of the 2 groups of patients were statistically different compared with those before treatment (P-adjust < .013 and P-adjust = .013, respectively). Moreover, treatment reduced the score of the acupoint embedding group by 3 points on average, while sham procedure reduced the score by only 0.52 points on average (Table 2 and Figs. 2–4; see Table S2, Supplemental Digital Content, http://links.lww.com/MD/K177, which shows the degrees of freedom, t value, Z value, etc).

Table 2.

Comparison of the VAS scores before and after treatment between the 2 groups. (mean ± SD, score).

VAS score	Group	Before treatment	After treatment	Within group comparison	Comparison between groups
				P-adjust	P-adjust
Anorectal pain VAS	Thread-embedding acupuncture	5.69 ± 2.17	2.69 ± 1.16	<.013**	<.013*
	Sham-embedding acupuncture	5.94 ± 1.45	5.42 ± 1.59	.013***
Abdominal distension and pain VAS	Thread-embedding acupuncture	3.89 ± 1.43	3.80 ± 1.45	1.000	1.000
	Sham-embedding acupuncture	4.19 ± 1.39	4.22 ± 1.40	1.000
Lumbar pain or soreness VAS	Thread-embedding acupuncture	3.83 ± 1.52	3.74 ± 1.48	1.000	1.000
	Sham-embedding acupuncture	3.78 ± 1.66	3.89 ± 1.67	1.000

^*P-adjust < .013 compared with the sham embedding group after treatment.

^**P-adjust < .013 compared to before treatment.

^***P-adjust = .013 compared to before treatment.

Figure 2.

The anorectal VAS scores. Patient scores were assessed before and after treatment and compared accordingly. * represents P < .05; SEA = the sham embedding group; TEA = the thread-embedding acupuncture group.

Figure 4.

The lumbar pain or soreness VAS. Patient scores were assessed before and after treatment and compared accordingly. SEA = the sham embedding group; TEA = the thread-embedding acupuncture group.

Figure 3.

The abdominal distension and pain VAS. Patient scores were assessed before and after treatment and compared accordingly. SEA = the sham embedding group; TEA = the thread-embedding acupuncture group.

In terms of the anal incontinence index, there was no significant difference in the anal incontinence index between the 2 groups of patients before treatment (P-adjust = 1.000). After the treatment, there was a statistical difference in the anal incontinence index between the 2 groups (P-adjust < .013). After treatment, the proportion of grade 0 patients in the acupoint embedding group increased from 5.7% to 34.3%, while the proportion of grade 1 patients increased from 37.1% to 54.3%, the proportion of grade 2 patients decreased from 40.0% to 8.6%, and the proportion of patients with grade 3 was significantly reduced from 17.1% to 2.9% (Table 3 and Fig. 5; see Table S3, Supplemental Digital Content, http://links.lww.com/MD/K178, which shows the degrees of unadjusted P values), indicating that TEA can effectively relieve anal incontinence and enhance anal control.

Table 3.

Comparison of the anal incontinence index between both groups before and after treatment [n (%)].

Before or after treatment	Group	Level 0	Level 1	Level 2	Level 3	P-adjust
Before treatment	Thread-embedding acupuncture	2 (5.7)	13 (37.1)	14 (40.0)	6 (17.1)	1.000
	Sham-embedding acupuncture	5 (13.9)	12 (33.3)	15 (41.7)	4 (11.1)
After treatment	Thread-embedding acupuncture	12 (34.3)	19 (54.3)	3 (8.6)	1 (2.9)	<.013
	Sham-embedding acupuncture	4 (11.1)	11 (30.6)	16 (44.4)	5 (13.9)

P-adjust < .013 compared with the sham-embedding group after treatment.

Figure 5.

The anal incontinence index. Patient scores were assessed before and after treatment and compared accordingly. * represents P < .05. SEA = the sham embedding group; TEA = the thread-embedding acupuncture group.

There was no significant difference in the SF-36 quality of life scores in all 8 domains between the 2 groups of patients before treatment (P-adjust = 1.000). However, treatment increased the physical functioning, role-physical, body pain and mental health scores in the acupoint-embedding group compared to those of the control patients (P-adjust < .0013). Moreover, scores of these dimension and role-emotional were improved within the acupoint-embedding group after treatment compared with before treatment (P-adjust < .0013). However, only the mental health scores of patients in the sham acupoint-embedding group were improved compared to the pretreatment scores (P-adjust < .0013; Table 4, Figs. 6 and 7; see Table S4, Supplemental Digital Content, http://links.lww.com/MD/K179, which shows the degrees of freedom, t value, Z value, etc).

Table 4.

Comparison of the SF-36 quality of life scores between the 2 groups before and after treatment (mean ± SD, score).

Dimension	Group	Before treatment	After treatment	Within group comparison	Comparison between groups
				P-adjust	P-adjust
Physical functioning	Thread-embedding acupuncture	38.57 ± 15.22	57.43 ± 13.25*,**	<.013**	<.013*
	Sham-embedding acupuncture	40.56 ± 13.67	42.64 ± 11.56	1.000
Role-physical	Thread-embedding acupuncture	44.29 ± 24.32	65.71 ± 26.49*,**	<.013**	<.013*
	Sham-embedding acupuncture	43.75 ± 24.91	41.67 ± 24.64	1.000
Bodily-pain	Thread-embedding acupuncture	38.00 ± 8.65	66.14 ± 10.03*,**	<.013**	<.013*
	Sham-embedding acupuncture	38.19 ± 8.71	37.75 ± 8.43	1.000
General health	Thread-embedding acupuncture	32.71 ± 9.58	32.86 ± 9.18	1.000	1.000
	Sham-embedding acupuncture	36.25 ± 12.39	35.83 ± 11.86	1.000
Role-emotional	Thread-embedding acupuncture	35.23 ± 26.75	62.87 ± 27.75**	<.013**	.273
	Sham-embedding acupuncture	37.96 ± 25.40	47.23 ± 28.05	.624
Social functioning	Thread-embedding acupuncture	52.07 ± 22.19	52.39 ± 22.00	1.000	1.000
	Sham-embedding acupuncture	51.86 ± 20.24	50.93 ± 19.60	1.000
Vitality	Thread-embedding acupuncture	34.29 ± 10.44	35.83 ± 12.36	1.000	1.000
	Sham-embedding acupuncture	34.29 ± 9.79	34.31 ± 12.37	1.000
Mental health	Thread-embedding acupuncture	42.51 ± 10.98	70.17 ± 11.94*,**	<.013**	<.013*
	Sham-embedding acupuncture	42.44 ± 10.83	57.56 ± 10.53**	<.013**

^*P-adjust < 0.013 compared to the sham embedding group after treatment.

^**P-adjust < 0.013 compared to before treatment.

Figure 6.

The SF-36 quality of life scores. Patient scores were assessed before and after treatment and compared accordingly. * represents P < .05. SEA = the sham embedding group; TEA = the thread-embedding acupuncture group.

Figure 7.

The SF-36 quality of life scores. Patient scores were assessed before and after treatment and compared accordingly. * represents P < .05. SEA = the sham embedding group; TEA = the thread-embedding acupuncture group.

Overall, the acupoint embedding treatment cured 1 patient (2.8%), showed a significant effect in 6 patients (17.1%), an effect in 23 patients (65.7%), and no effect in 5 patients (14.2%). In contrast, the sham embedding procedure cured no patients (0%), no patients showed a significant effect (0%), and 33 patients (91.6%) had no effect at all according to the therapeutic evaluation criteria. However, 8.3% of patients showed some effect. Thus, the total effective rate of the acupoint embedding treatment was 85.71%, whereas the total effective rate of the sham-embedding group was 8.33% (P-adjust < 0.0013; Table 5 and Fig. 8; see Table S5, Supplemental Digital Content, http://links.lww.com/MD/K180, which shows the degrees of freedom, chi-square value, etc).

Table 5.

Comparison of the clinical effective rate between these 2 groups [n (%)].

Group	n	Cured	Markedly	Effective	Invalid	Total effective rate (%)	P-adjust
Thread-embedding acupuncture	35	1 (2.86)	6 (17.14)	23 (65.71)	5 (14.29)	85.71	<.013
Sham-embedding acupuncture	36	0 (0.00)	0 (0.00)	3 (8.33)	33 (91.67)	8.33

P-adjust < .013 compared to the sham-embedding group.

Figure 8.

The clinical effective rate. Patient scores were assessed after treatment and compared accordingly. *P < .05. * represents P < .05. SEA = the sham embedding group; TEA = the thread-embedding acupuncture group.

3.3. Adverse reactions

The adverse reaction data were collected from all patients for local or subcutaneous bleeding, syncope, severe pain, and local infection. The data showed that there were no adverse reactions related to the procedures for both groups of patients during the treatment.

4. Discussion

TEA is a novel type of acupuncture used to extend acupoint stimulation via the retention and embedding of traditional acupuncture needles.^[12,13] Clinically, acupuncture is frequently used in China to reduce FAP symptoms via application to the “Du meridian,” “bladder meridian,” “kidney meridian,” and other meridian acupoints in order to channel meridians and activate collaterals, harmonizing Qi, blood, and Yin and Yang.^[20] TCM theory regards FAP as “Pohu pain” and a type of “depression syndrome” that is largely caused by emotional disorders and stagnation or deficiency of “qi and blood,” therefore, FAP induces “impassability leading pain and “malnutrition leading pain.”^[21] Because of this, FAP could be long lasting and difficult to heal, and in this regard, TEA may be effective to rebalance “yin and yang,” and regulate “zang-fu to promote “meridian Qi and “Qi and blood.”^[22] To confirm this TCM theory in FAP, we conducted a clinical trial and found that TEA treatment reached 85.7% total effectiveness versus 8.33% with sham treatment controls. Our data also revealed that TEA significantly reduced the anal rectum VAS score and improved quality of life in the treatment group compared to the control. There were no adverse reactions observed in both the TEA and control sham treatment groups during this clinical trial. We therefore, concluded that TEA was effective and safe to heal FAP and improve their quality of life of patients. However, further studies are needed to confirm our current data.

In Western medicine, FAP patients, especially patients with levator ani syndrome, are usually treated with electrogalvanic stimulation, biofeedback training, muscle relaxants (methocarbamol or diazepam), and digital massage of the levator ani muscles, while there is no suitable treatment for proctalgia fugax patients because of their short symptom duration.^[3] As an alternative to Western medicine, TCM may be used to treat and cure diseases for which there is no remedy in modern medicine.^[23–26] Indeed, TCM has its own theory and methodology in the diagnosis and treatment of patients.^[25,26] A recent study critically examined and provided an overview for TCM concepts, like “Qi,” “meridian,” “acupuncture,” “pulse and tongue diagnostics,” TCM herbs, and discussed TCM scientific literature in comparison with the current standard of the evidence-based research.^[26] A previous study showed that acupoint catgut embedding was able to attain an anti-inflammatory effect in patients by regulating the level of peptide hormones in the digestive tract and through a reduction in local inflammatory stimulation, leading to an improvement in anal muscle spasm induced-pain.^[27] Another study revealed that such a procedure also induced an increase in levels of nerve growth factors, thus helping to repair damaged pelvic floor nerves.^[28] Furthermore, a previous physiological and chemical study of the effects of the embedded suture showed that it could soften the subcutaneous anal tissue and pelvic floor muscles, while stimulating the muscles and ligaments around the anus to recover and strengthen the damaged muscles.^[29] Other studies have provided a mechanism of action of acupuncture-electroacupuncture in persistent pain^[30] where the electroacupuncture functioned by activating neurons and inhibiting inflammation.^[31] Our current study further confirmed the usefulness of TEA in manage FAP in this randomized controlled clinical trial, although further studies are required to understand the underlying molecular events occurring in these patients. However, due to the current COVID-19 pandemic, the data lack the posttreatment follow-up; thus, there are no data on the long-term efficacy of TEA in FAP treatment. Nevertheless, clinical TEA studies of pain showed that the long-term TEA efficacy was better than that of acupuncture alone.^[32] For example, a previous TEA study of lumbar disc herniation reported that the pain score in the TEA group was significantly improved compared with that of the acupuncture alone after 1 month treatment, although there was no significant difference in the improvement of JOA low back pain score and VAS pain score between TEA and acupuncture immediately after the treatment.

In our current study, the average age of FAP patients was 54.1 years old and 70.4% of enrolled subjects were females, indicating that FAP tends to occur in middle-aged and elderly women. These data are consistent with data from previous studies,^[3,33] although our patients were older (54.1 vs 48 years of the median age).^[3] Our current data also revealed that TEA treatment significantly improved anorectal VAS score, anal incontinence index, and SF-36 quality of life score compared to control patients. it was also true that the Control patients did show some improvement in these parameters after the sham procedure, indicating that close contact with physicians during treatment may help them to improve their symptoms by potentially alleviated their psychological anxiety, allowing them to physically and mentally relaxation. However, further study is needed to disclose the underlying mechanisms leading to clinical improvement in the control group.

Our current clinical trial does have some limitations. The treatment duration was relatively short and the sample size was also relatively small. These procedures are still invasive and uncomfortable, thus, long-term adverse effects need to be further evaluated. A future large patient population trial including participation from multiple institutional will be needed to verify our current data.

5. Conclusions

The data from the current randomized controlled clinical trial demonstrated the effectiveness and safety of the acupuncture-embedding thread on patients with functional anorectal pain without any clinical adverse reaction. A future study involving multiple institutions and a larger sample size is required to confirm our findings.

Acknowledgments

The authors would like to thank all patients for their participations in this study.

Author contributions

Data curation: Sufan Ma, Qixin Hua, Changcheng Cheng.

Investigation: Wanqi Lin.

Methodology: Qianyang Zhu.

Project administration: Cairong Zhang, Xueping Zheng.

Supervision: Qian Shi, Huijia Li.

Writing – original draft: Jingjing Li, Yuqing Sun.

Writing – review & editing: Jingjing Li, Katherine Thomas.

Supplementary Material

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