Does Injection at Acupuncture Sites Work Better Than Needling Alone?

Introduction
I’ve recently seen a couple of patients who were treated by Traditional Chinese Veterinary Medicine (TCVM) vets at other hospitals. The records from these vets include the usual pseudoscientific nonsense describing their conditions, such as “Rebellious Spleen Chi” or “Kidney Qi Deficiency.” And these patients have typically been given the usual untested and unregulated herbal remedies TCVM vest use, despite the serious risks these can present (in fact, a local woman was recently killed by a toxic herbal tea from a TCM apothecary shop). And of course, these patients received acupuncture treatment. However, these particular vets seem especially fond of a twist on the usual acupuncture practice that I’ve seen a few times before—the injection of Vitamin B12 into supposed acupuncture points.

I’ve discussed previously the general unreliability of the pre-scientific religion and folklore that make up TCVM theory. I’ve also investigated the evidence concerning acupuncture in exhaustive detail as part of my certification in veterinary medical acupuncture. While there is some limited evidence for possible clinical benefits to a very few needling practices, especially involving electrical stimulation of peripheral nerves, in general the value of acupuncture is probably slight, if any, and the use of TCVM to guide it is worthless. My focus here, then, is whether there is any advantage to injecting vitamins or other substances into purported acupuncture points (which quite likely don’t exist as discrete, consistently identifiable locations anyway; 1, 2).

The Evidence
There is, of course, some research literature comparing acupuncture injection to dry needling. Whether it makes sense to do such studies given the uncertainty about the theory and clinical effects of acupuncture in general is a serious question. In any event, such studies are not going to be very convincing when they only compare injection to standard acupuncture without some form of non-acupuncture or sham acupuncture control group. Often, such studies lack such controls, and so they may well only be comparing one placebo to another.

Another problem with the acupuncture injection literature is the choice, in some studies, to inject pharmaceuticals at proposed acupuncture points. By itself, again without proper control groups for comparison, this is more a comparison of drugs versus acupuncture than acupuncture injection versus plain acupuncture.

Finally, most of the acupuncture injection literature suffers from the usual weaknesses of acupuncture studies, not only lack of appropriate control groups but inadequate blinding, randomization, statistical analysis, or other flaws that leave the studies vulnerable to bias.

Here are a few examples:

Wade C, Wang L, Zhao WJ, et al. Acupuncture point injection treatment of primary dysmenorrhoea: a randomised, double blind, controlled study. BMJ Open. 2016 Jan 5;6(1):e008166. doi: 10.1136/bmjopen-2015-008166.

This one compared three groups:

Vit K injection at acupuncture point on both legs and saline in the buttock
Saline near but not at acupuncture point in both legs and Vit K in the buttock
Saline at acupuncture points on both legs and in the buttock

The goal was to measure changes in discomfort associated with menses. There was some blinding, in that patients and doctors didn’t know what they were injecting, but of course the doctors knew whether or not they were making the injection at an acupuncture point, so at least one group was not blinded for the doctors.

As usual, all groups reported less discomfort that before treatment, so placebo effects were certainly at work. The authors make much of the fact that there was a statistically significant difference between the group getting Vitamin K at acupuncture sites and the other groups. However, the differences between this group and the other two were from 1.1-1.8 points on an 11-point pain scale. By comparison, the control groups both improved by 4.5-5 points on this scale from baseline during the hour after treatment. This means the placebo effects were 4-5 times greater than any effect from the treatment itself, which doesn’t exactly suggest a meaningful real-world treatment effect.

Chen CY, Lin CN, Chern RS, et al. Neuronal Activity Stimulated by Liquid Substrates Injection at Zusanli (ST36) Acupoint: The Possible Mechanism of Aquapuncture. Evid Based Complement Alternat Med. 2014;2014:627342. doi: 10.1155/2014/627342. Epub 2014 Mar 6.

This one starts with the assumption that injection of drugs at acupuncture sites is more effective than acupuncture alone due to some kind of synergistic effects (an unproven assumption, like so many in alternative medicine). The study aims to identify the mechanism of this assumed effect.

The study compared injection of saline, Vitamine B1, Vitamin B12, and bee venom to plain needling at an acupuncture point. The outcome measured was the activity of a gene in the spinal cord (the study was done in rats). The assumption here was that greater gene activity meant greater stimulation at the acupuncture point, though what clinical relevance this would have is not obvious or addressed by the authors.

The results indicated no difference between the various treatments with the exception that bee venom appeared to generate more gene activity in the spinal neurons than the other forms of stimulation. The grand conclusion, then, would be that acupuncture injection is generally no different than plain needling except if you use something specifically designed by nature to irritate nerves like bee venom! It’s hard to see, though, how this sort of research justifies the practice of acupuncture injection in real-world patients.

There are a moderate number of similar studies that have the same sorts of limitations, but none that provide clear, high-quality data suggesting that acupuncture injection has significant clinical advantages over dry needling. Reviews of the acupuncture injection literature for specific medical conditions are typically inconclusive due to the lack of good-quality research. For example:

Wang LL, Guan L, Hao PL, et al. Acupuncture and vitamin B12 injection for Bell’s palsy: no high-quality evidence exists. Neural Regen Res. 2015 May;10(5):808-13. doi: 10.4103/1673-5374.156987.

“Because of study bias and methodological limitations, [our] conclusion is uncertain…”

Wang M, Gao YH, Xu J, et al . Zusanli (ST36) acupoint injection for preventing postoperative ileus: A systematic review and meta-analysis of randomized clinical trials. Complement Ther Med. 2015 Jun;23(3):469-83. doi: 10.1016/j.ctim.2015.03.013. Epub 2015 Apr 13.

“ST36 acupoint injections with various agents may have a preventive effect for POI. Safety is inconclusive as few of included trials reported adverse events. Due to the poor methodological quality and likely publication bias further robust clinical trials are required to arrive at a definitive conclusion.”

Bottom Line
Even overlooking the uncertainties about the meaning of Traditional Chinese Medicine theories and metaphors, the existence of acupuncture points as discrete and definable entities, or the clinical effects of acupuncture per se, there is little evidence to support the idea that injection of various substances at acupuncture points has significant advantages over needling alone at these points. Of course, the injection of drugs at acupuncture points may have greater effects than needling alone, but this is more likely due to the pharmacological effects of the drugs themselves, having little or nothing to do with the identification of the injection site as an acupuncture point.

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