PONV is one of the common complications after surgery, and the incidence of PONV is approximately 20%−30% after general surgery and up to 60%−80% in high-risk individuals (1, 2). PONV can lead to electrolyte imbalance, aspiration pneumonia and increased intracranial pressure. It may also prolong the length of hospital stay and increase the economic burden (3, 4). Despite the application of antiemetic medications and various novel therapies in recent years, these medications are only partially effective (5–7). Thus, PONV remains an important problem in the perioperative period.

Laparoscopic surgery has gained widespread clinical adoption due to its minimally invasive nature and rapid postoperative recovery. However, the procedure often necessitates pneumoperitoneum, which increases intra-abdominal pressure and may induce gastroesophageal reflux. Elevated intra-abdominal pressure may also stimulate the vagus nerve, thereby activating the vomiting center (8). Many antiemetic medications have been used to prevent PONV after surgery including 5-hydroxytryptamine-3 (5-HT3) receptor antagonists, neurokinin-1 (NK-1) inhibitors and dopamine receptor antagonists (9). In Western medicine, the primary mechanism is that opioids inhibit gastrointestinal motility through excitation of μ receptors in the central and gastrointestinal tract, resulting in decreased intestinal motility (10). However, monotherapy has certain limitations, and some patients with simple application of antiemetic medications still have unbearable PONV. Studies have shown that the failure rate of treatment with conventional antiemetic medications among obese patients can be as high as 45% (11, 12). The incidence rate of PONV is still around 20% in high-risk patients treated with a combination of dexamethasone and ondansetro (13). Due to the limitations of drug therapy for PONV, it is imperative to explore more non-pharmacological approaches to prevent PONV.

TEAS is a non-invasive treatment method derived from traditional Chinese acupuncture, in which electrodes are placed on acupoints to deliver electrical stimulation that induces the de qi sensation. It combines effects of peripheral nerve stimulation with the therapeutic principles of acupuncture (14). TEAS, based on traditional Chinese medicine acupuncture theory, has the advantages of non-invasion, convenient operation, few side effects and significant therapeutic effects. The mechanism by which TEAS can alleviate PONV may be by regulating autonomic homeostasis, correcting autonomic dysfunction, inhibiting catecholamine release and reducing gastrointestinal oedema (15). In addition, we selected the intervention was TEAS and excluded electro acupuncture (EA) because EA uses acupuncture, whereas TEAS uses electrode patches, which may affect the accuracy and robustness of the results.

There have been meta-analyses confirming the effectiveness of TEAS on nausea and vomiting after abdominal surgery under general anesthesia (16, 17). However, studies focused specifically on laparoscopic surgery have yielded conflicting results (16, 18), and there remains a lack of strong, up-to-date clinical evidence. Furthermore, previous reviews have often overlooked a critical analysis of the TEAS intervention parameters (e.g., time, frequency, intensity) and have not consistently evaluated TEAS as an adjunctive therapy to modern antiemetic protocols. Therefore, we conducted this updated systematic review and meta-analysis to assess the adjunctive effectiveness of TEAS in preventing PONV after laparoscopic surgery and to summarize the characteristics of the intervention protocols used. Therefore, we systematically searched for published articles, conducted a systematic review of the evidence, and performed meta-analysis to assess the effectiveness of TEAS in preventing PONV after general anesthesia.

The results of data synthesis demonstrated that the application of TEAS reduced the incidences of PONV, PON, and POV, reduce the use of postoperative antiemetic drugs and shorten the time to first flatus after surgery. This suggests that TEAS confers multiple benefits during the recovery period and helps to facilitate postoperative recovery. The most commonly used acupoints across the nine trials were PC6 (nine studies), ST36 (six), LI4 (five), and SP6 (three).

Our analysis of the time to first flatus revealed high heterogeneity (I² = 76%). To investigate this, we conducted a subgroup analysis based on the type of surgery. The results suggest that TEAS has a more consistent and significant effect in accelerating gastrointestinal recovery in patients undergoing non-gynecological laparoscopic surgery compared to those undergoing gynecological procedures. A possible explanation is that patients undergoing gynecological surgery, who are predominantly female, already have a higher baseline risk for postoperative gastrointestinal dysfunction due to hormonal influences and the specific nature of pelvic surgery. This higher baseline impairment might make the additional benefit of TEAS less pronounced or harder to detect compared to a more general surgical population. This finding highlights the importance of considering patient populations and surgical types when evaluating the efficacy of TEAS.

The precise mechanism by which TEAS alleviates PONV after laparoscopic surgery is multifactorial, but can be understood in the context of the procedure's specific physiological challenges. Laparoscopic surgery necessitates pneumoperitoneum, which increases intra-abdominal pressure and can cause significant vagal nerve stimulation, a primary trigger for PONV (8). TEAS, particularly at acupoints like PC6 and ST36, is thought to modulate autonomic nervous system activity, specifically by enhancing vagal tone in a regulatory manner (28). This may counteract the disruptive vagal stimulation from pneumoperitoneum and help restore normal gastrointestinal motility. Furthermore, the surgical stress inherent in laparoscopy triggers a neuroendocrine response, including activation of the hypothalamic-pituitary-adrenal (HPA) axis, which is linked to PONV (29). TEAS has been shown to attenuate HPA axis hyperactivity, thereby mitigating the stress response. This may be particularly relevant for the gynecological surgery patients included in our review, who are considered a high-risk population for PONV. Lastly, by stimulating Aβ and Aδ fibers, TEAS can trigger the release of endogenous opioids like endorphins in the central nervous system (30, 31), which not only contributes to analgesia but also modulates the chemoreceptor trigger zone and vomiting center. Clinical studies suggest broader perioperative benefits, including analgesia, immunomodulation, and complication reduction (31–33). In addition, the inflammatory response triggered by laparoscopic surgery may exacerbate PONV. TEAS exerts anti-inflammatory effects and may indirectly alleviate symptoms by down-regulating pro-inflammatory mediators such as IL-6 and TNF-α (34, 35).

It is also important to consider the heterogeneity within the control groups of the included studies. Eight of the nine trials employed a “sham TEAS” group, where patients were connected to a non-functional device, while one study used a “no TEAS” control. Studies using a sham TEAS control are methodologically stronger for assessing the specific physiological effects of the electrical stimulation itself, as they control for the powerful placebo effect associated with the ritual of applying electrodes and receiving attention. The inclusion of one study with a no-intervention control might slightly inflate the overall effect size. This distinction is crucial for interpreting the magnitude of the benefit attributed to TEAS and underscores the need for rigorous sham controls in future trials.

Meta-analys has demonstrated that TEAS is significantly effective in preventing PONV following general anesthesia (13). Our research indicates that TEAS effectively prevents PONV following laparoscopic surgery, consistent with previous studies. However, it is noteworthy that the study by Yan et al. (26), despite its significant weight in our analysis, did not show a statistically significant benefit of TEAS for the primary PONV outcome. Several factors might contribute to this discrepancy. Firstly, as the authors noted, the study population consisted exclusively of high-risk patients (Apfel score ≥ 3), where the baseline PONV incidence is exceptionally high, making it more challenging to demonstrate a significant effect from any single intervention. Secondly, the study employed a four-acupoint combination (LI4, PC6, ST36, SP6), which differs from other positive studies that used two or three acupoints. The specific synergistic or antagonistic effects of this combination warrant further investigation. Finally, the control group received standard prophylactic ondansetron, setting a high therapeutic bar for TEAS to show an additional benefit. This highlights the importance of context when interpreting results, particularly when TEAS is evaluated as an adjunctive therapy rather than a standalone one. In addition to gynecological procedures, RCTs covering other types of laparoscopic abdominal surgery were included. Thus, our study provides a more comprehensive assessment than the 2020 TEAS meta-analysis (16).

PC6 (Neiguan), located on the pericardium meridian, is effective in relieving PONV (36). According to the theory of Chinese medicine theory, the acupoints ST36 (Zusanli), located on Foot Yangming Stomach Meridian, can restore gastrointestinal function and alleviate PONV. Stimulation of ST36 can promote the recovery of gastrointestinal function and alleviate PONV (37, 38). LI4 (Hegu) is the original point of the large intestine channel of Hand Yangming Large Intestine Meridian. LI4 has been confirmed to be related to analgesic and sedative effects (39). In addition, a meta-analysis has shown that the use of LI4, PC6 and ST36 exerts a synergistic analgesic effect in laparoscopic surgery (40).

The Cochrane bias risk tool was used to assess the quality of the literature, and while most studies were rated as having a low risk of bias in key domains like randomization, we identified some articles with potential bias including selection bias, performance bias, detection bias and reporting bias, with a critical appraisal of performance bias being warranted. It is notoriously difficult to achieve effective participant and personnel blinding in TEAS trials; even when a sham device is used (i.e., identical electrode placement without electrical current), participants may discern the lack of sensation, potentially unblinding them to the intervention. This potential for unblinding constitutes a significant performance bias that could lead to an overestimation of the treatment effect due to placebo or expectation effects. Although we have reported the bias risk as assessed by the original study authors, readers should interpret the findings with caution, acknowledging that the true effect size of TEAS might be more modest than what is reported here, and this issue is a major challenge for the entire field of non-pharmacological stimulation research. The results of this meta-analysis demonstrated that the incidence of PONV and the need for remedial antiemesis within 24 h postoperatively were significantly lower in the TEAS group than in the control group. These findings align with those reported by Gao et al. (2) and Sun et al. (41), which suggest that TEAS enhances gastrointestinal function in patients undergoing general anesthesia, while notably differing from those of Zhang et al. (18), who found no significant effect of TEAS on PONV, and the discrepancy may be attributable to differences in surgical types and acupoint selection between the studies. In addition, no serious adverse events and treatment-related safety concerns related to TEAS were reported in the included studies, confirming its current safety and efficacy in clinical practice. Some patients may experience redness and itching on the skin where the surface electrode is applied, but this is not associated with any serious adverse events. Further studies are warranted to confirm the long-term safety of TEAS.

A key aspect that this meta-analysis aimed to address was the variability in TEAS intervention protocols. The most common stimulation frequency was a dense-disperse wave (2/100 Hz), utilized in the majority of trials. The intensity was typically adjusted to the patient's tolerance, usually described as a strong but non-painful sensation. The duration of stimulation also varied, with most studies applying TEAS for approximately 30 min before anesthesia induction and continuing it throughout the surgery. This lack of standardization makes it difficult to determine an optimal TEAS protocol. The heterogeneity in these parameters could contribute to the variability in treatment effects observed across studies. Future research should focus on head-to-head comparisons of different stimulation parameters to establish evidence-based guidelines for clinical practice.

In our meta-analysis, we included a larger number of patients and RCTs. Compared with previous meta-analyses, we highlight that the RCTs included herein explicitly documented the peri-operative administration of antiemetics such as dexamethasone or metoclopramide. Although the mechanism underlying the combined use of TEAS and antiemetic drugs remains unclear at present. This further supports the effectiveness of TEAS as a complementary therapy for preventing PONV.

In summary, our study suggests that TEAS, when used as an adjunctive therapy to standard pharmacological prophylaxis, can significantly decrease the incidence of PONV, PON, and POV, accelerate the return of postoperative bowel function, and reduce the use of rescue antiemetics. These findings indicate that TEAS is an effective and safe complementary intervention for managing PONV in the context of laparoscopic surgery. It may be promising to promote postoperative gastrointestinal recovery. Future studies of high quality and large samples are needed to support the clinical benefits of TEAS therapy on gastrointestinal function.