Acupuncture: Mechanisms and Uses in the Perioperative Context

Written By Angharad Bridges

Acupuncture is an iconic procedure of traditional Chinese medicine (TCM) which focuses on restoring balance to an imbalanced, ill body. TCM is centralised around ancient beliefs, still widely held, which posit that the human condition can be represented by meteorological states – such as dryness, dampness, wind, fire, cold and earth – which can each act to heal or hurt. Each state has yin and yang qualities – where yin describes states of nothing (dark, cold, tranquil), and yang describes states of much (heat, light, excess). Another important concept is qi, which is a vital life force or energy (like the Force in Star Wars – or rather, the Force was inspired by qi). TCM holds that blocked or stagnant qi causes imbalance between yin and yang, which in turn causes disease. Using these concepts, TCM crafts a qualitative image of the person – instead of a single diagnosis, a person’s health is summarised like a weather report. Acupuncture, and other TCM practices, seek to balance out these concepts by unblocking qi which improves the patient as a whole.

Scientific basis

Ancient doctors knew that, somehow, acupuncture has therapeutic benefits. But precisely how?

Acupuncture uses very thin needles (typically 0.18-0.3mm in diameter) or electrical stimulation (electroacupuncture) to pierce an acupuncture point (acupoint) on the skin to a depth between a few millimetres to a few inches, stimulating sensory nerves under the skin or in muscles. This can relieve pain, induce anaesthesia and reduce nausea, as well as having other effects. Over several millennia, the number of recorded acupoints on the human body has grown to over 2000. However, a single acupuncturist usually knows about 150.¹

Most of its current indications are for analgesia, so let’s start there.

In 1982, Professor Han of Beijing Medical College published a review titled Neurochemical basis of acupuncture and analgesia. Contained within this review was the culmination of all research and knowledge about the modulation of various pain pathways by acupuncture in all of cats, rats, rabbits, dogs and humans. Despite acupuncture’s history stretching back more than two millennia, its scientific study began not long ago from the time of the review’s publication.

Professor Han led a group undertaking novel research in endogenous opioid mechanism activation in acupuncture. His group and others demonstrated through experimentation that naloxone, a potent opioid receptor antagonist, reversed the painkilling-effects of acupuncture in a variety of laboratory animals and humans.⁶ One experiment conducted by DJ Mayer showed that acupuncture reduced electrically induced tooth pulp pain in humans, and naloxone reversed this analgesic effect.

But pain is complex. It involves many interconnected networks, such that, piece by piece, researchers have demonstrated connections between various signalling pathways, each acting to potentiate or attenuate the feelings we describe as pain. It makes pharmacology so challenging that sometimes even morphine doesn’t touch the pain felt by patients experiencing chronic neuropathic pain.⁶ Nevertheless, acupuncture has been shown to act on several pain pathways at once, earning its place as one of the most researched and respected alternative therapies.

The raphe nuclei are groups of neuron cell bodies implicated in pain signalling located at the midline of the brainstem. Neurons projecting from these nuclei use the neurotransmitter serotonin (also called 5-hydroxytryptamine) to send signals. The raphe nuclei send neurons down into the spinal cord to change the spinal cord’s response to painful stimuli, as well as upwards into the thalamus and hypothalamus to reduce pain. Research has shown that damage to these pathways reduces the effect of acupuncture – in other words, acupuncture stimulates the raphe nuclei and serotonergic system to reduce pain, but these systems need to be intact for there to be any effect. Notably, experiments that blocked serotonin breakdown by administering a monoamine oxidase inhibitor increased the analgesic effect of acupuncture, and adding naloxone did not reduce this effect.⁶

Additionally, experiments have shown that acupuncture could reduce pain by influencing activity of the locus coeruleus, which is a paired nucleus located in the pons of the brainstem. As with the raphe nuclei and the opioid system, pharmacological manipulation of the locus coeruleus neurotransmitter, noradrenaline, exhibits the role of noradrenaline signalling in acupuncture. Studies show that the locus coeruleus contributes to feedback inhibition of acute pain by releasing noradrenaline in its descending pathway, which binds to α2-adrenoceptors on ascending spinal cord fibres. Α2-adrenoceptors are inhibitory receptors, and their activation on spinal cord fibres reduces noradrenaline signalling. Experimental evidence supports the idea that decreasing central nervous system noradrenaline signalling reduces pain; administering dihydroxyphenyl serine, a noradrenaline precursor that “skips the dopamine step” in noradrenaline synthesis, reduces the efficiency of acupuncture; on the other hand, acupuncture’s analgesic effect was potentiated after administering the tyrosine hydroxylase inhibitor α-methyl-p-tyrosine (tyrosine hydroxylase is necessary for noradrenaline synthesis).⁶ This evidence seems to conclude that increasing central nervous system noradrenaline reduces the effectiveness of acupuncture, whereas decreasing noradrenaline improves it. But what is less clear is how acupuncture actually modulates the locus coeruleus. A review of human and animal experimental data from 2017 looked at twelve studies on the effects of electroacupuncture on the locus coeruleus; six showed that acupuncture increased locus coeruleus activity, whereas six studies reported the opposite. The review concludes that the frequency of electroacupuncture could alter its precise effects on the locus coeruleus, but it is hard to draw conclusions from studies that practised acupuncture in variable ways to produce such heterogeneous results.

Acupuncture is also widely used for the treatment of nausea and vomiting. Acupressure wristbands are widely available and are often used to reduce nausea and prevent vomiting, such as during travel. These wristbands are embedded with a plastic bead that presses on the Nei-Guan pressure point on the anterior wrist. Experiments have shown that precise acupressure at this point alters gastric myoelectrical activity and increases pituitary secretion of beta-endorphins and adrenocorticotropic hormone (ACTH), which both inhibit the brain’s vomiting centre.

Post-operative Complications

In 2025, a systematic review of sixteen randomised controlled trials (RCTs) was published which looked at post-operative pain relief and functional improvement in 1315 patients who had undergone surgery for a tibial fracture. For each RCT, the intervention group received acupuncture alongside conventional rehabilitation (including pharmacological treatments and physiotherapy, among other things), whereas the control group received conventional rehabilitation only.

Due to heterogeneity between studies, not all studies were used for analysis of each outcome. Pain was assessed in only five of the sixteen studies (341 patients) using the patient-reported visual analogue scale (VAS). Acupuncture significantly improved VAS scores; however, even within these five studies, there was still considerable heterogeneity between results (I²=84%), making the pooled results less reliable. The effective rate, assessed in seven studies (636 patients), was almost 400% higher in the intervention group (95% CI [2.79, 8.68]); additionally, patients in the intervention group were 87% less likely to experience post-operative complications (95% CI [0.06, 0.26]), which was assessed in eight studies (644 patients).¹¹

By stimulating nerves and muscles under the skin, acupuncture has been shown to improve function as well as reduce pain, explaining these promising results. However, the studies included in the systematic review had several limitations. Single blinding was not done for any of the RCTs included, largely increasing the risk of a placebo effect. Each study had strikingly different results for some outcomes – heterogeneity – such as in the pain outcome. Side effects were also poorly described. Finally, fifteen out of sixteen studies were conducted in China, which limits generalisability to other populations.

Another challenging aspect of surgical recovery is nausea and vomiting, often due to the effects of anaesthesia. A systematic review of five RCTs (366 patients) published in 2025 reported on the effectiveness of acupuncture for nausea and vomiting after cholecystectomy (gall bladder removal). The results shone a very positive light on acupuncture – patients receiving acupuncture were 90% less likely to experience nausea (95% CI [0.03-0.34], p=0.0003) and 89% less likely to experience vomiting (95% CI [0.01-0.85], p=0.03) than participants who did not receive acupuncture.

As always, there were a number of limitations with this systematic review. Firstly, the number of studies included, and therefore the number of patients, is small, which limits generalisability. Additionally, the method of acupuncture used in each study varied between electroacupuncture, auricular acupuncture, and traditional acupuncture, and the therapy received by the control group ranged from sham acupuncture (“inactive” acupuncture using realistic needles not inserted deep enough or inserted into fake acupoints) to nothing at all. Despite these limitations, this study is unique in that two of five papers were published outside of China (one paper published in Brazil, the other in the USA), thereby containing a high proportion of patients who are not Chinese – a common limitation in acupuncture studies – suggesting that these promising results may be generalisable to other populations outside East Asia.

Case By Case Basis

In June 1972, the Scottish journalist Sandy Gall, who was also a presenter for Independent Television News, travelled to China and televised to Britain a surgery which used acupuncture as the sole surgical anaesthetic. The 1970s marked the beginning of the end of China’s two-decade long political isolation from the West. It also marked acupuncture’s entry into mainstream media when the New York Times journalist James Reston published an article detailing his acupuncture treatment post-appendectomy. After Reston’s article, Western journalists like Gall flocked to China to report more on this curiosity.

The patient, undergoing an ovarian cyst removal, had inserted into acupoints in her forehead and nose several needles which were being electrically vibrated. Gall reported that this particular hospital utilised acupuncture in one third of all its surgeries, including in brain and heart surgery. Despite being conscious for the whole operation, the patient reported that she felt no pain. Extraordinarily, the surgeon even asked the patient to “push”, facilitating the removal of the cyst. Speaking through a translator:

“Did you feel any pain?”

“No. She said no pain.”

“Did she feel anything at all?”

“When the incision was made on the skin, she felt as if something brushed against the skin of her abdomen. And when the cyst was being removed, she felt a sense of retraction, as if something tense was happening to her abdomen. After the cyst was removed, she felt a very light sensation, as if something very heavy had been removed.”

“Does she feel very weak now, or very tired?”

“She hasn’t any feeling of tiredness.”

After watching a recording of the televised surgery, I felt that this case flew in the face of everything I understood about surgical procedure. Patients undergoing surgery were meant to be completely unaware, dressed in drab gowns, apathetic to the life-altering changes happening to them. Here, the patient was humanised, even contributing as an active participant in her own surgery.

Could acupuncture replace standard surgical anaesthesia?

Several systematic reviews have reported that acupuncture is an effective adjunct to pharmacological anaesthesia, reducing the required dosage of intraoperative anaesthetic drugs. Some studies even report lower post-operative inflammation with perioperative acupuncture use. However, acupuncture cannot generally provide the level of  anaesthesia required for most surgeries and has been phased out in surgeries carried out in China. Total anaesthesia is required to prevent muscle tension and stretch reflexes, and there are many surgeries for which patients must be unconscious.

Nevertheless, the potential of acupuncture to reduce post-operative pain and nausea should not be ignored. This case demonstrates an intensely impressive therapeutic potential for acupuncture, but many studies report markedly different outcomes for different patients. Variation in therapeutic effect is expected in almost every study, but for acupuncture it appears to be so inconsistent that it is untrustworthy – might it be that we are better off observing acupuncture’s therapeutic effect on a case-by-case basis, without trying to integrate our statistics to population-level studies?

The issue of evidence

Currently, the National Institute for Health and Care Excellence (NICE) deems that the evidence supporting acupuncture for a few conditions – chronic pain, migraines, prostatitis, and hiccups – is acceptable.⁴ Despite all the promising data embedded in this article, patients undergoing surgery are not typically offered acupuncture as part of their care. It also doesn’t help that there is no statutory regulation of acupuncture in the UK, making trialling difficult and its practice suspicious to many healthcare professionals.

This comes down to the issue of acupuncture evidence. We can apply the typical reasons that evidence may be considered inconclusive, such as publication bias, whereby publications showing that a treatment is effective are more likely to be published. However, acupuncture research faces more intrinsic issues.

Results from RCTs assessing the efficacy of acupuncture are continuously called into question. One of the most obvious barriers to RCT design is blinding – single blinding may be possible with sham acupuncture, but double-blinding is not possible because the acupuncturist administering treatment will know if their treatment is true or sham. Additionally, if a single acupuncturist knows only 150 out of 2000 acupoints, then practice is likely to vary between them. Studies often don’t report the exact acupoints used because practitioners may use different techniques for different patients – for the patient is not an abstract diagnosis, but a condition of states to be balanced.

Even single-blind trials using sham acupuncture face a barrier made indomitable by the very nature of acupuncture: if there are more than 2000 recorded acupoints – and there are probably many more unknown – how can we be sure that placing a needle in a “fake” spot is truly fake, and that it does not induce some sort of stimulation in itself?¹⁹

One example of this was illustrated by a study from 2026, which sought to explain how acupuncture can ameliorate memory deficits. Functional connectivity within the brain was observed using functional MRI scans of 50 patients with amnestic cognitive impairment, randomising patients to either true or sham acupuncture. Functional connectivity between the left locus coeruleus and left inferior parietal lobe was significantly increased (p=0.002) in patients receiving real acupuncture, but the sham acupuncture also significantly affected brain connectivity between the left locus coeruleus and cerebellum. Overall, true acupuncture was more effective, but it is evident that we cannot reduce acupuncture to the abstract notion that a single, targetable, “correct” acupoint will produce a quantifiable effect. Perhaps the gold standard of Western medical research, built on optimising drug regimens, is not suited to judging the complexities of a practise which has pre-existed it for millennia?

The evidence attests that acupuncture works for some indications which coheres with laboratory evidence. There is potential for use of adjunct acupuncture in standard surgical care. A brief search of the literature demonstrates that acupuncture is not limited to a single type of surgery, but has been trialled and used as part of orthopedic, cardiac, abdominal and laparoscopic surgeries. Its mechanism of action also has the advantage of not conflicting with the use of pharmacological interventions that we have so rigorously tested. For this area of research to progress in the UK, we first need better regulation of acupuncture practice. Then, we need a mindset shift that values acupuncture not as a drug intervention with easily quantifiable effects, but as a tool that can ease the process of surgery (and other conditions) for patients, many of whom are very weak, chronically ill and experiencing drug therapeutic failure.

Read the rest of the edition here.