The Efficacy & Safety of Electroacupuncture for Pain Management Cathryn Hu, Ph.D., O.M.D., L.Ac. Advanced Acupuncture, Inc. Los Angeles, California American Academy of Pain Management 19 th Annual Clinical Meeting Nashville, TN September 11, 2008
EA induction and recovering profiles of acupuncture analgesia involvement of hormonal factors
Supported by cross-perfusion experiments in which acupuncture induced analgesic effect was transferred from the donor rabbit to the recipient rabbit when the cerebrospinal fluid (CSF) was antiserum against endorphins suggests that endorphins are involved.
More recent research found the release of endorphins into CSF following EA
The low frequency (2Hz) and high frequency (100 Hz) of EA selectively induces the release of enkephalins and dynophins in both experimental animals and humans.
Clinical studies suggesting the effectiveness for the treatment of various types of pain, depression, anxiety, spinally induced muscle spasms, stroke, gastrointestinal disorders and drug addictions.
Ulett GA, Han S, Han JS., Biol Psychiatry 1998 Jul 15;44 (2):129-38
Acupuncture points are special conduits for electrical signals
The anatomical structures are characterized by lower electrical impedance compared to adjacent controls.
Aug. 2007, 16 articles (18 experiments) showed positive association between acupuncture points and lower electrical resistance and impedance.
5/9 point studies showed positive association between acupuncture points and lower electrical impedance.
7/9 meridian studies showed positive association between acupuncture meridians and lower electrical impedance and higher capacitance.
The preliminary findings are suggestive and offer future directions for research based on in-depth interpretation of the data.
Ahn AC , et all
Bioelectromagnetics , 2008 May;29(4):245-56
Electro-acupuncture vs. Nerve Block for Treatment of Radicular Sciatic
Applied electro-acupuncture to the spinal nerve root by inserting needles under x-ay imaging in 3 cases of radicular sciatica
In all 3 cases, symptoms were markedly reduced immediately after treatment.
Sustained effect was noticeably longer than that of spinal nerve blocks in 2 of the pervious cases.
Suggest the descending inhibitory control, inhibitory control at the spinal level. Inhibition of potential activity by hyper-polarization of nerve endings or changes in nerve blood flow may be involved in the mechanism of the EA.
Results suggest the EA to the spinal nerve root may be superior to lumbar spinal nerve block when it is applied appropriately. Acupuncture in Medicine 2005 March; 23(1):27-30
Electro-acupuncture direct to spinal nerves as an alternative to selective spinal nerve block
in patients with radicular sciatica - a cohort study by Motohiro Inoue, Tatsuya Hojo, Tadashi Yano, Yasukazu Katsumi
Clinical studies in outpatient have investigated the chronic cervical or low back pain
Reduced pain and remifentanil consumption during oocyte aspiration when compared with conventional auricular acupuncture or a sham treatment.
Large-scale studies are required to evaluate the analgesic efficacy of auricular EA
“ P-Stim Auricular Electro-acupuncture stimulation device for pain relieve” By Sator-KatzenschlagerSM, Michalek-Sauberer A.
Expert Rev Med Devices. 2007 Jan;4(1):23-32
Suppression of morphine withdrawal by EA in rats
100-Hz EA or 100 Hz Tens was very effective in ameliorating the morphine withdraw syndrome in rats and humans.
Methods: Rats were made dependent on morphine by repeated morphine injection (5—140 mg/kg bid X 8 days)
Evidences: A marked increase in tall flick latency was observed: The effect of 100 Hz EA could be blocked by naloxone at 20 mg/kg, but not at 1 mg/kg.
1. 100-Hz EA induced analgesia observed in morphine dependent rats is mediated by kappa-opioid receptors.
2. a significant decreases of the concentration of dynophin A (1-17) immunoreactivity was observed in the spinal perfusate in morphine-dependent rates that could be bought back to normal level by 100-Hz EA
3. 100-Hz EA was every effective in suppressing NX= precipitated morphine withdrawal syndrome.
4. The effect of EA could be prevented by intrathecal administration of nor-BNI (2.5 micrograms/20microliters, a kappa- opioid receptor antagonist, or dynophine A (1-13) antibodies administered 10 min prior to EA
5. The steady state spinal dynophin release is low in morphine-dependent rates, it can be activated by 100-Hz EA stimulation, which may be responsible for eliciting an analgesic effect and ameliorating morphine withdrawal syndrome.
Wu LZ , Cui CL , Tian JB, Ji D , Han JS. Brain Res. 1999 Dec 18;851(1-2):209-6
Analgesia induced by EA of different frequencies
Cross tolerance techniques to analyses the receptor mechanism of analgesia induced by EA of 2-Hz, 100-Hz, or 2-15 Hz.
Rats were given EA stimulation of each frequency for 30 min with 30 min. intervals successively.
TFL was taken to indicate the intensity of EA analgesia
Rats made tolerant of repeated intrathecal injection, showed a cross-tolerance to 100-Hz and 2-15 Hz, but not to 2 Hz.
Rats made tolerant to 2-15 Hz EA showed cross-tolerance to either 2-Hz or 100-Hz EA analgesia
Rats made tolerant to either 2 Hz or 100-Hz were still reactive to 2-15 Hz-EA.
2-Hz-EA analgesia is mediated by mu- and delta-receptors
100 HZ EA analgesia is mediated by kappa-receptor
2-15Hz-EA analgesia by combined action of mu-delta- and kappa receptors in the spinal cord of the rats.
Chen X H , Han J S . Behav Brain Res. 1992 Apr 10;47(2):143-9
Characteristics of EA induced analgesia in mice
3 inbred strains/3 outbreed strains of mice.
2 pair of metallic needles were inserted into acu -points ST-36 and Sp-6 connected to an EA generator
EA parameters were set as constant current output with alteration of a positive and negative square wave, 0.6ms in pulse width for 2 Hz and 0.3 ms for 100 Hz.
Tauk-flick latencies evoked by radiant heat were measured before, during and after EA stimulation
1. DBA/2 mice showed a significantly more potent analgesic effect than the other five strains in response both to both 100 and 2 Hz EA
2. EA analgesia increased as the intensity of stimulation increased from 0/5 to 2/0 mA, but it remained at this plateau when the intensity further increased from 2.0 to 3.0 mA.
Results: EA induces reliable, strain-dependent analgesia in mice.
The naloxone-reversibility of EA, a measure of whether it is opioid or non-opioid mediated, is dependent upon intensity and frequency.
Huang C , Wang Y , Han JS , Wan Y . Brain Res . 2002 July26;945(1):20-5
EA is useful addition to MA when patient not responding well with MA
Due to multi-factorial nature of chronic pain, need for a multidisciplinary treatment
Short term pain relieve could be achieved from 50-70% of the patients.
Long term results are not promising
Clinical research of poor quality of the studies available for analysis precludes definite conclusions.
Adrian White, reviewing the clinical application of EA, has concluded that it results in a long-term benefits in around 25% of chronic pain, could that this form of EA was more effective for musculoskeletal conditions that for neuropathic pain.
EA found to be more effective than MA for both pain reduction and restoration of autonomic and tropic functions in patients with chronic post-traumatic pain.
EA appeals to be more effective short-term pain relief than MA.
Randomized trial of long term effect of acupuncture for shoulder pain
A randomized, placebo controlled trial with independent evaluator set in a primary care clinic in Spain
Age: 25-83 years with shoulder pain
Randomly allocate to EA or skin no-penetrating placebo-acupuncture over 8 weeks.
Primary measurement of pain intensity by lattinen index, in ROM, functional ability (SPADI) and quality of life (COOP-WONCA charts)
Assessments were performed before, during, 3 and 6 months after treatment.
Conclusion: 6 months post treatment, the acupuncture group showed a significantly greater improvement in pain intensity. The acupuncture group had consistently better results in every secondary treatment for patients with shoulder pain.
Guerra de Hoyos, JA et, all , Pain , 2004 Dec;112(3):289-98