Efficacy of electroacupuncture on the recovery of gastrointestinal function after laparoscopic cholecystectomy: a systematic review

CAI Wa (蔡媧), LIU He (劉禾), ZHANG Kun (張堃), GAO Yuan (高垣), SHEN Weidong (沈衛東)

Shuguang Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 201203

Abstract Objective: To evaluate the efficacy of electroacupuncture (EA) in enhancing the recovery of gastrointestinal function after laparoscopic cholecystectomy (LC).

Keywords: Acupuncture Therapy; Electroacupuncture; Laparoscopic Cholecystectomy; Randomized Controlled Trials;Systematic Review; Meta-analysis

Postoperative gastrointestinal dysfunction (PGD) is a well-known complication that occurs after abdominal surgeries, including laparoscopic cholecystectomy (LC).PGD is characterized by an impairment of gastrointestinal function, including delayed flatus, bowel movements, and defecation, as well as nausea,vomiting, and intolerance of eating.With a morbidity rate of 10%-30%[1-2], PGD significantly impacts the postoperative recovery quality of patients.The delayed recovery of gastrointestinal function increases the risk of postoperative complications and prolongs hospitalization[3-4].Moreover, PGD can lead to fluid,electrolyte, and acid imbalance and even intestinal obstruction in severe cases[5-6].As a result, the regulation of gastrointestinal function plays an important role in enhanced recovery after surgery.

Various techniques, including exercises[7], the use of opioids[8], and non-steroidal anti-inflammatory drugs(NSAIDs)[9], have been reported to have a positive effect on the recovery of gastrointestinal function.However,opioids are associated with common adverse reactions such as constipation and nausea, while even low doses of NSAIDs can cause headaches, dizziness, stomachache,sickness, and diarrhea.Therefore, it is imperative to find an effective treatment option with minimal adverse reactions to manage PGD.Electroacupuncture (EA)emerges as a promising alternative with the potential to meet these requirements and provide relief to patients.

EA was reported to be an effective and feasible treatment to enhance the recovery of gastrointestinal function in a number of studies[10-13].Nevertheless, the efficacy of EA for the recovery of gastrointestinal function after LC remains unclear.Thus, a meta-analysis was conducted to evaluate the efficacy of EA in restoring the gastrointestinal function of patients after LC.Following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA)checklist, the protocol of the meta-analysis was registered in the International Prospective Register of Systematic Reviews (PROSPERO), and the registration number was CRD42022321525.

1 Methods

1.1 Search strategy

The following databases were searched from inception to December 10, 2022 to identify relevant studies: Excerpta Medica Database (EMBASE), PubMed,Cochrane Library, Wanfang Academic Journal Full-text Database (Wanfang), China National Knowledge Infrastructure (CNKI), Chongqing VIP Database (CQVIP),and China Biology Medicine Disc (CBM).The following terms were searched: electroacupuncture, electroacupuncture, EA, laparoscopic cholecystectomy,cholecyst, laparoscopic surgery, laparoscopy,gastrointestinal function, and gastrointestinal dysfunction.“OR” was used between two search terms with similar definitions.“AND” was used between multiple search terms with different definitions.No restriction on language was applied.

1.2 Inclusion criteria

Only randomized controlled trials (RCTs) were included without language restrictions; all patients after LC regardless of age, gender, race, and country; only studies of EA treatment in the postoperative period were included; control interventions included one of the following treatment methods: physical/mental training therapy, general care, and pharmacotherapy;the time to the first flatus was the primary outcome.

1.3 Exclusion criteria

EA combined with any other traditional Chinese medicine (TCM) therapies; repeatedly published studies;studies with no access to the full text.

1.4 Literature screening

Two researchers were responsible for literature screening independently according to the inclusion criteria.They reviewed and screened the titles and abstracts to exclude irrelevant studies.Full texts were checked for further evaluation.Any disagreement was resolved via discussion with a third researcher.

1.5 Data extraction

Data extraction was carried out by 2 researchers independently.Extracted information included first author, country, number of participants, publication year, treatment details, and outcome measurements.Disagreements between researchers were resolved by discussion.

1.6 Quality assessment

The Cochrane tool was used to evaluate the risk of bias.Seven domains were considered, including allocation concealment, random sequence generation,blinding of outcome assessment, blinding of participants and personnel, selective reporting,incomplete outcome data, and other sources of bias.For each domain, the judgment of low risk, high risk, or unclear risk of bias was made based on the information provided by the authors.

1.7 Publication bias assessment

The publication bias was assessed by funnel plots when more than 10 studies were included.

1.8 Statistical analysis

Review Manager software (V.5.4.1) was applied to conduct the meta-analysis.Mean difference (MD) was used to evaluate the treatment effect on continuous outcomes, with a confidence interval (CI) of 95% used as an effective size for the analysis.A random-effects model was applied, and theI2statistic was calculated to check the possibility of statistical heterogeneity.I2<50%suggested no obvious heterogeneity, whileI2≥50%indicated substantial heterogeneity.In cases of substantial heterogeneity, sensitivity analysis or subgroup analysis was conducted to identify the source of heterogeneity.The difference was considered statistically significant ifP<0.05.

2 Results

2.1 Literature search

We obtained 1 001 records after retrieval.Seven studies[14-20]were ultimately included in the metaanalysis.The process of literature retrieval and screening is presented in Figure 1.

2.2 Characteristics of included studies

Out of the 7 studies analyzed, a total of 225 patients were in the EA group, and 226 patients were in the control group.On average, 2.4 acupuncture points were selected, with Zusanli (ST36) and Neiguan (PC6) being the most frequently used points.Specifically, Zusanli(ST36) was selected in 6 studies[14-18,20], and Neiguan(PC6) was selected in 4 studies[14-16,18].Patients in the control group in all included studies received standard care.The time to the first flatus was reported in all included studies to assess the recovery of gastrointestinal function after LC.Of them, 4 studies[15-17,19]recorded the time to the first defecation,and 3 studies[14,15,19]reported the time to the first bowel movement.All included studies were conducted in China and written in Chinese.Table 1 outlines the general characteristics of the included studies.

2.3 Quality assessment

All included studies were reported to be randomized,with only one study[19]not stating the method of random sequence generation.Two studies[16,18]reported the procedure of allocation concealment.Considering that blinding of patients in the control groups was not possible,all included studies were judged as having an unclear risk of bias in blinding methods.A low risk of bias for incomplete outcome data or selective reporting domains was found in all studies.Figure 2 and Figure 3 illustrate the risk of bias assessment for each study.

Figure 1 Flow chart of literature screening

Figure 2 Ratio of risk of bias in the included studies

Figure 3 Assessment of risk of bias in the included studies

2.4 Time to the first flatus

Meta-analysis: The effectiveness of EA on the time to the first flatus after the surgery was examined.No obvious heterogeneity was found (P=0.29;I2=18%).Meta-analysis results showed that the time to the first flatus in the EA group was significantly shorter compared to that in the control group [P<0.000 01,MD=-5.32, 95% CI (-6.42, -4.21)].The details are shown in Figure 4.

2.5 Time to the first bowel movement

Meta-analysis: The time to the first bowel movement after the surgery was reported in 3 studies[14,15,19].Despite a substantial heterogeneity (P=0.04,I2=68%), it was found that EA group had a significantly shorter time to the first bowel movement than the control group[P<0.000 01, MD=-6.22, 95% CI (-8.11, -4.34)].See Figure 5.

Sensitivity analysis: Sensitivity analysis was conducted due to the substantial heterogeneity(I2=68%).Following the principle of PATSOPOULOS N A,et al[21], we deleted one of the studies[19]that had the greatest influence on heterogeneity (I2=0%).Compared with the control group, the EA group still had a significantly shorter time to the first bowel movement[P<0.000 01, MD=-5.27, 95% CI (-6.57, -3.97)].See Figure 6.

2.6 Time to the first defecation

Meta-analysis: Four studies[15-17,19]recorded the time of the first defecation after LC.Substantial heterogeneity was found in the outcome indicators(P=0.003,I2=79%).The combined effect size MD was-11.08 [95% CI (-15.78, -6.39)].See Figure 7.The comprehensive effect size test showedZ=4.63 andP<0.000 01.The results showed that the time to the first defecation was significantly shorter in the EA group than that in the control group.

Sensitivity analysis: The high heterogeneity of the meta-analysis (I2=79%) was followed by the sensitivity analysis.No heterogeneity was detected after deleting the study of QU L Z,et al[15](I2=0%).The results after sensitivity analysis were consistent with the original findings, indicating that the EA group had a significantly shorter time to the first defecation than the control group [P<0.000 01, MD=-8.31, 95% CI (-10.92, -5.71)].See Figure 8.

2.7 Publication bias

Publication bias analysis was not performed because the number of the included studies was smaller than the required threshold for such an analysis (<10).

Figure 4 Forest plot of the time to the first flatus after laparoscopic cholecystectomy

Figure 5 Forest plot of the time to the first bowel movement

Figure 6 Sensitivity analysis: forest plot of the time to the first bowel movement

Figure 7 Forest plot of the time to the first defecation

Figure 8 Sensitivity analysis: forest plot of the time to the first defecation

3 Discussion

LC is a minimally invasive technique that is commonly used for patients diagnosed with cholelithiasis or cholecystitis due to its advantages, including minimal trauma, less bleeding, and fewer postoperative complications.Nevertheless, PGD, such as a prolonged flatus, bowel movements, and defecation, is still common in most patients, especially in the elderly[9,22-23].As a result, enhancing the recovery of gastrointestinal function after surgery has become a key concern.Early mobility and medications that promote gastrointestinal motility are the current treatment methods[1,7,9].However, side effects of the medications can limit their efficacy.

Due to its minimal adverse reactions and significant therapeutic effects, EA has become a popular treatment option for PGD patients of abdominal surgery and vascular surgery[24-29].A study[30]has reported that EA not only promotes the recovery of gastrointestinal function but also reduces the occurrence of gastrointestinal complications such as nausea, vomiting,and poor appetite.In previous studies, various manifestations, such as flatus, bowel sounds, and bowel movements, were used to evaluate gastrointestinal function[3,31].However, due to the inability of clinicians to consistently monitor bowel sounds[32], the time to the first flatus and the time to the first defecation were commonly used to assess postoperative gastrointestinal function.Moreover, a systematic review[6]showed that the time to the first flatus had important clinical significance in terms of the recovery of gastrointestinal function.As a result, we used the time to the first flatus as the primary outcome to evaluate the recovery of gastrointestinal function as most related clinical trials did[25,33].Once gastrointestinal motility is restored, flatus and bowel movements will recover, and excretion will return to normal[34].The absence of flatus or bowel sounds 48 h after the surgery is considered a sign of PGD.

According to the results of the meta-analysis,significant improvements involving time to the first flatus, bowel movements, and defecation were found in the EA group compared to the control group.In summary, EA treatment during the postoperative period can significantly enhance the recovery of postoperative gastrointestinal function of patients after LC, which provides a new strategy for the prevention of PGD after LC.

However, this study had several limitations.First, the included studies had unclear risk bias in blinding methods for both participants and outcome assessors.Second, 5 out of 7 included studies had unclear allocation concealment.Third, those included studies had a small sample size.In future studies, the methods of blinding and allocation concealment need to be clarified.The efficacy of EA treatment on other factors,such as the length of hospitalization and quality of life,should also be investigated.

In conclusion, this study showed that the EA treatment had better effects on the recovery of gastrointestinal function after LC compared with general care.

Conflict of Interest

The authors declare that there is no potential conflict of interest in this article.

Acknowledgments

This work was supported by the Project of National Natural Science Foundation of China (國家自然科學基金項目, No.82004444); Pudong Traditional Chinese Medicine Training Plan of Pudong New Area Health System (浦東新區衛生系統浦東名中醫培養計劃, No.PWRzm2020-05); Scientific Research Projects of Shanghai Municipal Health Commission (上海市衛生健康委員會科研項目, No.2021LPTD-004, No.20204Y0472); Scientific Research Project of Science and Technology Commission of Shanghai Municipality (上海市科學技術委員會科研計劃項目, No.20Y21902900);Clinical Technology Innovation Project of Municipal Hospital ( 市級醫院臨床科技創新項目, No.SHDC22021210).The registration number of this study in the International Prospective Register of Systematic Reviews (PROSPERO) is CRD42022321525.

Authors’ Contributions

The study was designed by CAI Wa and SHEN Weidong.CAI Wa, LIU He, ZHANG Kun, GAO Yuan, and SHEN Weidong performed the study.CAI Wa analyzed the data and drafted the manuscript.All authors read and approved the final manuscript.

Received: 15 December 2022/Accepted: 18 May 2023