Contemporary Medical Acupuncture Program

Neurofunctional Treatment of Pain with Movement Disorders

Contemporary Acupuncture: a successful mechanism-based model for chronic pain management

By Dr. Alejandro Elorriaga Claraco
February 1, 2007

by Alejandro Elorriaga Claraco, MD (Spain), Director McMaster Contemporary Acupuncture Program and Angelica Fargas-Babjak, MD, Chair McMaster Contemporary Acupuncture Program

Whether acute or chronic, each pain problem is a personal experience with a unique combination of dysfunctions, sensory signals, and complex emotions. The main difference between acute and chronic pain is that in the latter tissue injury can no longer be used as the guiding model to explain symptoms. Instead, a neurobiological model that takes into account contributions by the peripheral and central nervous systems needs to be used. Processes such as peripheral and central sensitization are now key players in the maintenance of the sensory components of the pain problem. In addition, central processes related to the cognitive and affective dimensions of pain are also fundamental contributors to the experience.

Therefore, when dealing with a chronic pain problem, the challenge is to accurately define every level of dysfunction and to take a multi-level, multi-dimensional approach to correct as many affected mechanisms as possible. In these instances, one of the best therapeutic interventions available to clinicians and patients is contemporary acupuncture, a modality with a multi-level effect in the central nervous system.

Regarding the production of analgesia, acupuncture and electroacupuncture have shown to induce the release of numerous neurotransmitters and neuropeptides at different levels of the peripheral and central nervous system with modulatory effects on the transmission and processing of nociceptive signals. For instance, muscle pain studies by Professor C.H. Takeshige have demonstrated that there are at least two specific mechanisms involved in the production of muscle analgesia in response to acupuncture stimulation. One is the improvement of perfusion in the painful muscle mediated by autonomic vascular reflexes and the release of nitric oxide, the other is the activation of several endogenous pain inhibitory systems that act predominantly modulating nociceptive traffic at the spinal cord, and that involves the participation of several neurotransmitters such as serotonin and noradrenalin.

Based on a review of 228 basic research studies, professor Bruce Pomeranz has offered a theory of acupuncture analgesic effects based on specific neural pathways and neurohumoral responses, that complements the one proposed by professor Takeshige. Dr. Pomeranz proposes that acupuncture activates specific nerve fibers, such as small myelinated A-delta fibers and the type II-III muscle sensory afferents, that send impulses to the spinal cord that continue to supraspinal centers in the mid-brain, the hypothalamus, and the pituitary gland, triggering the release of different neuropeptides and neurohormones such as beta-endorphine, ACTH, and many more, with the overall effect of general modulation of pain and the regulation of several neuroendocrine and immune functions.

Some substances released in response to acupuncture stimulation, such as enkephalin, may help explain some of the observed effects of this therapy in the immune system. These simultaneous effects on the most important information systems of the body (nervous, endocrine, and immune systems) can be described with the contemporary term neuroimmunomodulation, which emphasizes the concept of the permanent intercommunication that exists among these systems. Possible mechanisms of neuroimmunomodulation associated with acupuncture include the potent anti-inflammatory effect of met-enkephalin, which may even prevent anaphylactic shock, or the enhancement of activity of natural killer cells and T cells by the different kinds of enkephalins.

Apart from its remarkable effects on pain and dysfunction of the locomotor system, there are also numerous documented effects of acupuncture on digestive function (motility and secretions), cardiovascular system (heart rate, blood pressure, etc.), gynecological and genitourinary systems, autonomic nervous system (xerostomia, nausea), limbic system (addictive behavior), mood control, especial senses, and a few others.

This impressive array of effects is due to the multilevel response — local, spinal segmental, and supraspinal — induced by the stimulation of specific neuroreactive sites with acupuncture needles and electricity. These neuroreactive sites are currently defined in anatomical terms and correspond with areas rich in sensory receptors such as neurovascular bundles on the limbs, sensory nerve trunks, muscle bellies, motor points, muscle-tendon junctions, teno-periosteal attachments, and joint capsules and ligaments.

In conclusion, contemporary acupuncture is a simple peripheral nerve stimulation technique that is used following a mechanism-based approach. This approach allows for better integration of electroacupuncture with other modalities for the benefit of pretty much any chronic pain sufferer. Response to treatment in these complex cases has to be evaluated in conjunction with the effects of the other interventions utilized.