Emily Mangan Acupuncture exists within the philosophical framework of traditional Chinese veterinary medicine (TCVM) with over 2,000-year history of use in veterinary species [1]. Acupuncture is the stimulation of acupuncture points (acupoints) which are externally palpable depressions present on the body surface that are associated with peripheral nerve bifurcation, transition through facial planes, and innervation of muscle and tendon [2–5]. Acupuncture points have been characterized histologically by a high density of free nerve endings, arterioles, venules, lymphatics, and mast cells compared to surrounding tissues [2, 3, 6, 7]. Acupuncture points are most commonly found on meridians, which is a TCVM concept that describes a complicated network of channels throughout the body that interconnect internal organs with each other and the body surface to facilitate the transmission of energy and nourishment [8, 9]. Scientifically, meridians align with the peripheral nervous system and the current, best supported hypothesis for acupuncture function lies in the neuroanatomic and neurophysiologic mechanisms described in the literature [2, 10]. Meridians and acupuncture points have been found to have specific properties that define them from surrounding tissue, including higher electrical conductance and capacitance [11–13], lower electrical resistance and impedance [11–13], propagation of heat along meridians [14, 15], and preferential transmission of fluids along meridian lines [8, 16, 17]. Acupuncture meridians have also been defined optically [18], magnetically [14], with acoustic signals [11, 14] and by the myoelectrical activities [14]. This data strongly supports neuroanatomical and neurophysiologic mechanisms of acupuncture. While there is a near-exponential growing body of evidence for the use of acupuncture in veterinary medicine developed over the last 50 years, it is still a young field and there remain swaths of clinical conditions that still require exploration and validation via blinded, controlled clinical trials. In the West, the most frequent applications of acupuncture in standard clinical practice include analgesia for post-operative, geriatric, and sports medicine applications [19], nausea [20, 21], neurological disorders including intervertebral disc disease, and epilepsy, and has been shown to have cardiovascular, gastrointestinal motility, and respiratory effects [19, 22–33]. Beyond these categories which have the support of high-quality clinical studies, acupuncture may be applied in a great many situations for treatment of a wide variety of conditions, although there is need for randomized blinded, placebo-controlled studies, as the majority of information available on additional clinical conditions has been taken directly from TCVM philosophy or experience of practitioners. Acupuncture stimulation has potent analgesic properties, which remain the best studied of all the clinical applications [7, 34, 35]. There is great interest in both human and veterinary medicine for analgesic uses, as acupuncture is non-pharmaceutical, does not interact with medications, is safe when used appropriately, and is efficacious. Analgesic effects of acupuncture, which have been rigorously explored scientifically, have been determined to be due to a cascade of effects, beginning with needle stimulation within an acupoint [7, 34, 35]. Stimulation creates local counterirritation within the acupoint characterized by release of local inflammatory mediators and endogenous opioids, and stimulates A⍺, Aβ, Aδ, and C nerve fibers [2, 6]. Stimulation progresses segmental effects by release of endogenous opioids and cytokines within the spinal cord [2, 36, 37], and culminates in suprasegmental effects, characterized by specific and consistent brain region activation and release of β-endorphins, enkephalins, noradrenaline, dopamine, and serotonin [2, 10, 38]. Acupuncture for post-surgical analgesia has been explored in the literature with encouraging results. In a study evaluating post-surgical analgesia in dogs undergoing routine ovariohysterectomy, acupuncture, and pharmacopuncture (1/10th the standard dose) with morphine and carprofen were just as effective as standard doses of parenteral morphine or carprofen [39]. Another study investigated acupuncture analgesia for soft tissue surgery in dogs undergoing mastectomy and the finding suggest that high-frequency electroacupuncture may be more effective in this clinical setting at managing post-operative pain than the standard dose of morphine [40]. Electroacupuncture (EAP) for post-operative pain management after hemilaminectomy for thoracolumbar intervertebral disc disease in dogs resulted in significantly lower total dose of fentanyl in the first 12 hours post operatively in dogs that received EAP, as well as significantly lower pain scores in the first 36 hours after surgery, compared to dogs receiving conventional pain management alone [41]. Clinical studies also support the use of acupuncture for pain associated musculoskeletal conditions. Acupuncture was found to be more effective for thoracolumbar pain in horses compared to phenylbutazone, and in a study of lameness in dogs, acupuncture improved quality of life, comfort, and mobility compared to conventional treatments alone [23, 42, 43]. While acupuncture has powerful analgesic properties, it should never be relied upon as a sole method of analgesia for procedures, and is best utilized as part of a comprehensive multimodal analgesic plan. Studies investigating the efficacy of acupuncture for the treatment and management of neurologic conditions has shown it is effective for epilepsy, cervical spondylomyelopathy, and intervertebral disc disease [44–49]. Gold bead implantation into acupuncture points decreased seizure frequency with reduced doses of anticonvulsant mediations, acupuncture treatment resulted in return to function in 85% of dogs with cervical spondylomyelopathy compared to 20% in the conventional treatment group, and the application of acupuncture for animals suffering from intervertebral disc disease (IVDD) is one of the best-studied neurologic applications [44, 45]. Dogs suffering ambulatory paraparesis have a significantly shorter time to recovery of ambulation proprioception when treated with electroacupuncture compared to corticosteroids, and a greater percentage of recovery compared to surgery or corticosteroids alone [46–48]. Acupuncture is effective for lowering high blood pressure, normalizing heart rate, and reducing heart rate variability [50]. The mechanisms of cardiovascular effect are still under-researched, but the current hypothesis includes sympathetic and parasympathetic regulation. Stimulation at the acupoint GV-26 increased cardiac output, stroke volume, heart rate, mean arterial pressure, and pulse pressure, and decreased total peripheral resistance [51]. The acupoints PC-6 and BL-15 were found to significantly increase heart rate in animals with induced xylazine-induced bradycardia, and these same points also significantly decreased heart rate in animals with glycopyrrolate-induced tachycardia. [52, 53] This is an example of dual-direction regulation: a physiologic response to stimulation of acupuncture points facilitates homeostasis [19]. These last two studies, where the same two acupoints either increased or decreased heart rate, is an excellent example of this principle [19]. Acupuncture is known to produce a parasympathomimetic-like effects as well as modulate the balance between the sympathetic and parasympathetic nervous systems [50]. While the mechanisms of respiratory effect are not fully elucidated, there is data showing that acupuncture has clinical indications for the management of respiratory conditions. Needling of GV-26 was found to cause a faster return to spontaneous ventilation in anesthetized turtles compared to epinephrine, as well as faster time to movement, and faster time to complete recovery [54]. In a cross-over study of tracheal collapse in small breed dogs, acupuncture treatment resulted in improved heart rate variably, reduced coughing, and reductions in oxidative stress after exercise compared to no treatment [50]. Acupuncture has a homeostatic effect on the parasympathetic and sympathetic nervous systems, which is apparent in its effect on the cardiovascular and respiratory regulation. These same principles also influence gastric and intestinal motility. Acupuncture stimulation at ST-36 and BL-27 have been shown to increase intestinal motility, and stimulation at PC-6 and ST-36 were found to slow gastric emptying time [55, 56]. These studies also demonstrate the principle of dual-direction regulation. Acupuncture also has antiemetic properties. Dogs with vasopressin-, hydromorphone-, or morphine-induced vomiting showed reduction of vomiting/retching episodes after acupuncture stimulation [57–59]. While more clinical studies are indicated, these studies demonstrate that acupuncture influences gastrointestinal motility, gastric emptying time, nausea, and vomiting. When comparing sedation after injection of dexmedetomidine administered either intramuscularly in gluteal muscles versus into GV-20, dogs that received injection into GV-20 had significantly increased sedation and analgesia, with longer duration of action. [60] Stimulation of GV-20 was also found to reduce EEG spectral edge frequency and achieve acceptable levels of sedation [61]. A study by Perdrizet et al. investigated immunostimulation properties of acupuncture by way of injection of the canine distemper vaccine into GV-14 versus control in 100 healthy dogs. There was a significant increase in canine distemper virus serum neutralization titers following injection at GV-14 compared to control [62]. Acupuncture has been found to be effective for the treatment of a variety of clinical applications and to influence the sympathetic and parasympathetic nervous system. While more research is required to further elucidate mechanisms and quantify effects, these studies demonstrate clinical efficacy of acupuncture mechanisms in veterinary species. There is a wide variety of modalities available to stimulate acupuncture points, each with their own indication and efficacy. While dry needling is the traditional method of stimulation, other methods, such as electroacupuncture or laser therapy, are growing in popularity in the veterinary field. Selection of a specific acupoint stimulation modality depends on diagnosis and patient goals, patient preferences, and tolerances, availability for follow up, and practitioner comfort. Dry needling is the insertion of a thin needle into the acupuncture point and may include various manipulations of the tissue including pricking, lifting, spinning, or fanning (Figure 6.1) [63]. The proposed mechanism of dry needling is direct disruption of tissue, resulting in stimulation of nerve fibers and mast cell degranulation, as well as additional stimulation from fascial interactions due to needle manipulation, and all resulting cascades previously discussed. Figure 6.1 A – A domestic cat with chronic kidney disease receiving dry needle acupuncture at Shan-gen to stimulate appetite. B – Administration of pneumo-acupuncture at BL-54 for treatment of muscle atrophy secondary to equine protozoal myeloencephalitis (EPM). C – Figure 6.7 A yellow Labrador Retriever receiving acupressure at GB-33. D – Electroacupuncture is administered to an equine patient with sacroiliac osteoarthritis. E – Photobiomodulation (cold laser) therapy at Hua-tuo-jia-ji along the site of a hemilaminectomy for treatment of intervertebral disc disease (IVDD). F – A yellow Labrador Retriever receiving moxibustion at Bai-hui. G – Hemoacupuncture at Xiong-tang resulting in a drop of dark stagnant blood. H – Aqua-acupuncture with vitamin B12 is administered via a winged infusion set along the Bladder Meridian in an equine patient with back pain. Dry needle acupuncture is less potent than some other methods, and typically requires frequent initial treatments (1–2x weekly for several weeks) followed by a period of elongation of interval between treatments, for clinical resolution or stable management of disease. Electroacupuncture (EAP) is the use of low-amplitude electrical current to stimulate acupuncture points and meridians (Figure 6.1). Electrical leads from an electrostimulation device that generates electrical current are connected to a set of acupuncture needles, which completes the circuit within the body [35, 63]. The amplitude of the wave is adjusted to patient tolerance [63]. Compared to dry needling alone, EAP provides more stimulation, which provides a longer lasting and more potent effect [32]. The electrical frequency utilized for treatment has been shown to influence the neurochemical mediators released [2]. Low-frequency stimulation (2–10 Hz) preferentially releases enkephalins, endorphins, noradrenaline, and acetylcholine, and has been shown to be effective for analgesia for chronic conditions. Moderate frequency (50–100 Hz) stimulation has been shown to preferentially release dynorphins and be muscarinic and GABAergic, and high frequency (200 Hz) has been shown to release serotonin [2]. High-frequency acupuncture has a short duration of action, but is potent and may be effective for acute or surgical pain [63]. Aqua-acupuncture or aquapuncture is the injection of a variety of substances subcutaneously or intramuscularly into acupuncture points, depending on the described depth of the acupoint itself [63]. Commonly injected fluids include saline, Vitamin B12, autologous blood, and pharmaceuticals [63]. Injection of fluid into an acupuncture point provides local distention of the area and prolonged stimulation of the tissue, thereby providing a longer lasting treatment than dry needling alone. Pharmacopuncture is a form of aquapuncture, and is defined by the injection of small amounts (1/10th the standard parenteral dose) of medications into acupuncture points [60, 64–66]. Pharmacopuncture with analgesics and sedatives have been shown to be efficacious in veterinary species in achieving sedation and decreasing requirements of additional analgesic after surgical procedures [39, 64–66]. Hemoacupuncture or hemopuncture is the treatment of an acupuncture point with the specific intent to cause bleeding from the acupoint (Figure 6.1). In Chinese medicine, this is considered a release of Excess and Heat, and is useful for conditions of high fever, severe stagnation, or severe inflammation, such as laminitis [3, 63]. Pneumoacupuncture is the injection of air into the subcutaneous space for treatment of regional muscle atrophy or to release fascial adhesions (Figure 6.1) [67]. Historically, pneumoacupuncture was performed by cutting a small hole in the skin and then lifting the skin manually to create negative pressure and facilitate influx of air. With the advent of medical instruments, air can simply be injected with a hypodermic needle and syringe, which also allows direct quantification of the injected air. The principles of pneumoacupuncture for treatment of muscle atrophy have been hypothesized to cause a release of fascial tension which allows unrestricted blood and lymphatic flow and increased nutrient availability to tissues. Occasionally, acupuncture points may be sterilely implanted with a bead or wire made of surgical stainless steel, gold, or titanium [63, 68]. The goal of implantation acupuncture is to provide prolonged stimulation of acupoints that have been shown to relieve symptoms in the patient [68]. Moxa is a dried herb, typically Artemisia sinesis (mugwort), that is frequently processed into a roll and lit on one end until it is smoking, and then held above the acupuncture point or needle to provide a warming stimulation (Figure 6.1) [63]. Moxibustion is particularly useful in patients that feel cold due to suffering from the Cold pathogen or Yang deficiency, patients who are elderly, or those who live in cold climates. In patients aversive to more invasive techniques, or for owners looking to safely provide stimulation at home, acupressure may be of clinical use. Acupressure is the application of pressure over an acupuncture point either with digits or wooden or plastic massage stick to provide stimulation (Figure 6.1) [63]. Typically, the acupoint is stimulated by pushing, rubbing, or pinching for 1–3 minutes before moving on to the next acupoint. Utilizing infrared photobiomodulation (frequently referred to as cold laser) for stimulation of acupuncture points (Figure 6.1) has shown to be efficacious for a variety of conditions, especially analgesia, when compared to therapy of sham-acupuncture points [10, 69]. Efficacy has been shown between 630–904 nm at 5–500 mW [63
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Integrative Acupuncture: Clinical Approaches and Current Scientific Literature
Introduction
Evidence-based Studies
Analgesia
Neurologic Disorders
Cardiovascular
Respiratory
Gastrointestinal
Sedation
Immunostimulation
Evidence-based Acupuncture Summary
Acupuncture Methods
Dry Needling
Electroacupuncture
Aqua-acupuncture
Pharmacopuncture
Hemo-acupuncture
Pneumoacupuncture
Implantation
Moxibustion
Acupressure
Photobiomodulation (Cold Laser)
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