Part 1
Philip A.M. Rogers MRCVS
e-mail :
1980, 1982, updated 1993, 1995
Postgraduate Course in Veterinary AP, Sydney, 1991


Surgical analgesia can be produced by methods involving peripheral or central stimulation, such as acupuncture (AP) analgesia (AA). The most common method is Electro-Acupuncture Analgesia (EAA), using a special electrostimulator attached to needles in AP points.

The major advantages of AA or EAA are its safety in high-risk patients and excellent post-operative pain relief, freedom from complications and enhanced healing which follows surgery under AA. The major disadvantages are the long induction period (10-40 minutes) and variable degrees of analgesia, even in skilled hands.

Many combinations of AP points can be used to induce EAA in large and small animals and there is no agreement on which combination is best for which operation. However, certain points have marked analgesic effects. They are LI04,11; TH08; PC06; points along the GV Channel; (BaiHui, WeiGan, TianPing, SanTai; ChihYi points); points between the digits (BoKoKu, InKoTen in dogs; second interdigital space in rabbits), certain Earpoints; the Root of the Ear; LU01; BL23,30; ST25,36,44; SP06; GB34; and X 35. Sometimes needles are inserted parallel to (or at both ends of) the incision, together with some of those points.

The choice of point combinations depends largely on the personal preference and experience of the operator. However, it is useful to consider the Channels in relation to the operation site and to choose points from (a) distant points on Channels whose superficial, deep, collateral or other branches pass through the operation site, plus (b) local points near the operation site, plus (c) points along nerves supplying the operation site or related to the operation site by spinal reflexes.

There is no agreement on the choice of stimulation parameters, although work by Toda et al, Matsumoto and others show that these can be critical. Further research in this area is needed.

The mechanisms of AA involve stimulation of peripheral sensory nerves, spinal cord and supraspinal areas (thalamus, midbrain and hypothalamus). Release of endorphin and serotonin activates a descending pain-inhibition mechanism. ACTH release assists healing. Extra-spinal and autonomic transmission may also be involved in AA mechanisms.

Stimulation-Produced Analgesia (SPA) and Transcutaneous Electro-Stimulation Analgesia (TESA) are closely allied with EAA and involve endorphin release. Vaginal Stimulation Analgesia (VSA) appears to use different mechanisms. Electro-restraint ("Stockstill") appears to be quite a different phenomenon and may have little analgesic effect.

Electro-Narcosis, Electro-Anaesthesia and Electro-Sleep (Cerebral Electro- Therapy) differ from the other techniques, as they cause unconsciousness during Electro-Stimulation (ES).

Combining AP and western concepts, as in combination anaesthesia, will lead to development of safer and more reliable methods of surgical anaesthesia.


Acupuncture (AP) can be used to obtain pain relief in clinical disorders or as an alternative or complementary method of inducing pain control during surgical procedures.

AP analgesia (AA) is a misnomer. It should really be called AP hypoalgesia. It is a pain inhibition phenomenon caused by stimulation of peripheral nerves via certain AP points. The degree of pain inhibition may be complete or partial.

In vet surgery, the AA technique, if applied carefully, often is sufficient to allow surgery without the use of other anaesthetics. Consciousness is retained throughout the operation but many animals become slightly drowsy (as if slightly sedated) during and for a short time after AA stimulation. All other sensations (touch, traction, pressure, tickle etc) and reflexes (to sight or sound stimuli, fear, traction etc) are intact.

AA can be induced by simple AP (manual twirling of the needles) but it is more common to use electrical stimulation (ES) via the needles. In this case the technique is called Electro-AP analgesia (EAA).

In emergencies a slight degree of hypo-algesia can be obtained in humans and animals by heavy digital pressure over the correct AP/nerve points. This method may have application in time of war or national disasters, when anaesthetists and anaesthetics may not be available. AA also can be induced by other stimuli, such as injection or electro-static fields applied to the points. Since the late 1980s, research on uses of low-power (cold) Laser as an AA stimulus is ongoing, with some positive results. However, it is too early to attempt to assess that method.

Stimuli via the AA points are carried in the peripheral sensory nerves to the spinal cord. They reach the midbrain via the ascending spino-thalamic tracts. In the midbrain the ascending signals cause release of endorphin, serotonin and other neurotransmitters which activate a "descending inhibition mechanism" and prevent the "pain signals" from the surgical area from reaching the cerebral cortex. Thus, AA can be said to "close" various "pain gates" in the nervous system. These gates are thought to be located in the spinal cord, thalamus and possibly other areas. The result is that the human (and, presumably, the animal) patient can feel the knife, the touch and traction etc but does not "feel pain".

Stimulation-Produced-Analgesia (SPA): Since the 1970s, western researchers, working independently of the Chinese, found that various types of stimuli applied indirectly or directly to the nervous system can reduce or abolish clinical and operative pain. Transcutaneous Electro-Stimulation Analgesia (TESA) has been used in childbirth in the human female and is somewhat comparable to EAA. Dorsal Column Stimulation (DCS) of the spinal cord has been used in intractable pain in humans. ES via electrodes implanted in specific sites in human or animal brain can induce a high degree of analgesia, usually involving the entire body. Direct ES of human thalamic or spinal areas can abolish clinical pain. Vaginal stimulation (electrical or mechanical) can cause potent whole-body analgesia in rats.

SPA has some similarities to AA. The main difference between these methods is that SPA tends to cause "whole body" analgesia, whereas the area of analgesia is much more localised in AA and is related to the site of the AA stimulation.

This paper will discuss the following topics:

1. types of operation successfully done under AA

2. equipment and methods of restraint used

3. techniques in large and small animals

4. advantages and disadvantages of AA in animals

5. mechanisms of AA

6. other methods of SPA (vaginal stimulation analgesia, electro-restraint, electro-narcosis and electro-sleep)