Neurohormonal theory:- Pain
transmission can also be modulated at many other levels
in the brain along the pain pathways, including the periaqueductal gray, thalamus,
and the feedback pathways from the cerebral cortex back to the thalamus. Pain
blockade at these brain locations is often mediated
by neurohormones, especially those that bind to the opioid receptors
(pain-blockade site). Some studies suggest
that the Analgesic (pain-killing) action of acupuncture is associated
with the release of natural endorphins in the brain. This effect can
be inferred by blocking the action of endorphins (or morphine)
using a drug called naloxone. When naloxone
is administered to the patient, the analgesic
effects of morphine can be reversed, causing the patient to feel pain
again. When naloxone is administered to an acupunctured patient, the analgesic
effect of acupuncture can also be reversed, causing the patient to report
an increased level of pain. It should be noted, however, that studies
using similar methodological procedures, including
the administration of naloxone, have suggested
a role of endogenous opioids
in the placebo response, demonstrating
that this response is not
unique to acupuncture. Such
analgesic effect can also be shown to last more than an hour after acupuncture
stimulation by recording the neural activity directly in the thalamus
of the monkey's brain. Furthermore, there is a large overlap between
the nervous system and acupuncture trigger points (points of maximum
tenderness) in myofascial pain syndrome.
Evidence suggests that the sites of action
of analgesia associated include the thalamus using fMRI (functional magnetic
resonance imaging) and PET (positron emission tomography)
brain imaging techniques, and via the feedback pathway
from the cerebral cortex using electrophysiological recording of the nerve
impulses of neurons directly in the cortex, which shows inhibitory action
when acupuncture stimulus was applied. Similar effects have been observed
in association with the placebo response. One study using fMRI
found that placebo analgesia was associated with decreased
activity in the thalamus, insula and anterior cingulate cortex Recently acupuncture
has been shown to increase the nitric oxide levels in
treated regions and resulting in increased
local blood circulation, an outcome found in other
studies. Effects on local inflammation and
ischemia have also been previously reported.
Safety and risks:- Because acupuncture needles penetrate the skin, many forms of acupuncture are invasive procedures, and therefore not without risk. Injuries are rare among patients treated by trained practitioners. In most jurisdictions, needles are required by law to be sterile, disposable and used only once; in some places, needles may be reused if they are first resterilized, e.g. in an autoclave. Certain forms of acupuncture such as the Japanese Toyohari and Shonishin often use non-invasive techniques, in which specially-designed needles are rubbed or pressed against the skin. These methods are common in Japanese pediatric use.
Common, minor adverse events:- A
survey by Ernst et al. of over 400
patients receiving over 3500 acupuncture treatments
found that the most common adverse effects from acupuncture were:-
* Minor bleeding after removal of the needles, seen
in roughly 3% of patients. (Holding a cotton ball for about
one minute over the site of puncture is usually sufficient to stop the bleeding.)
* Hematoma, seen in about 2% of patients, which manifests
as bruises. These usually go away after a few days.
* Dizziness, seen in about 1% of patients. Some patients have a conscious
or unconscious fear of needles which can produce dizziness
and other symptoms of anxiety. Patients are usually treated lying down
in order to reduce likelihood of fainting.
Other injury:-
Other risks of injury from the insertion of acupuncture needles include:
* Nerve injury, resulting from the accidental puncture of any nerve.
* Brain damage or stroke, which is possible with very deep needling at the
base of the skull.
* Pneumothorax from deep needling into the lung.
* Kidney damage from deep needling in the low back.
* Haemopericardium, or puncture of the protective membrane surrounding
the heart, which may occur with needling over
a sternal foramen (a hole in the breastb one that occurs as the result of
a congenital defect.)
* Risk of terminating pregnancy with the use of certain acupuncture
points that have been shown to stimulate
the production of adrenocorticotropic hormone (ACTH) and oxytocin.
These risks are slight and can all be avoided through proper training of acupuncturists. For correct perspective, their risk should be compared to the l evel of side effects of common drugs and biomedical treatment - see below. Graduates of medical schools and (in the US) accredited acupuncture schools receive thorough instruction in proper technique so as to avoid these events.
