Heat stimulation on the skin for medical treatment: can it be controlled?

OBJECTIVES: It has become increasingly important for evidence-based medicine to have a proper control for randomized-controlled trials. However, appropriately controlling manual therapies such as moxibustion has proved challenging. Our team designed a novel device based on sensory illusion, and tested its feasibility. DESIGN AND RESULTS: A sham moxibustion device was constructed to allow participants to feel moxibustion treatment without actually stimulating the corresponding acupoint. The device consisted of two pieces of aluminum, each shaped like a horseshoe, so that the center of the device would not touch the skin. Participants perceived two heat stimuli as one when the distances of two heat sources were within 15 mm on the forearm. The thermal stimulation of the sham device was adjusted to the lowest possible temperature, but enough to elicit a heat sensation (39°C), while that of verum was set at around 44°C. The subject blinding, tested in 30 healthy volunteers, was successful. With the exception of 1 subject, subjects in the sham group described the sensation as a warm solid circle, unable to differentiate between two-pieced sham moxibustion and verum moxibustion. CONCLUSIONS: This preliminary study indicates that this device may serve as an appropriate control for clinical studies of moxibustion, but more research is clearly needed. A validated sham moxibustion device based on sensory illusion may contribute in expanding knowledge of somatosensory studies.

Comparison of biomechanical properties between acupuncture and non-penetrating sham needle.

OBJECTIVES: A non-penetrating sham needle has been considered as a reliable control treatment in the field of acupuncture research. However, some concerns with regard to the credibility of sham needles have also been raised. We investigated whether there were differences in biomechanical properties and acupuncture sensation ratings in the process of needling between verum acupuncture (VA) and sham acupuncture (SA). METHODS: To quantify biomechanical force during needling in a cross-over design, we used a computer-controlled needling system. Fourteen participants received VA or SA at acupuncture point LI4, with no visual impact. They were asked to complete an acupuncture sensation form, including penetration, acute pain and DeQi sensations, and to identify the needling type they received. RESULTS: We found that there was a significant difference in insertion force between VA and SA (68.5 ± 12.2 vs. 27.2 ± 3.9 gf; p < 0.001). Participants clearly distinguished between the two kinds of stimulation and rated higher sensory ratings in the VA session (penetration sensation: 4.9 ± 3.1 vs. 1.7 ± 2.3, acute pain: 4.9 ± 2.7 vs. 1.9 ± 2.6, respectively; p < 0.01). CONCLUSIONS: Our findings demonstrate that differential biomechanical forces such as insertion and pullout force contribute to the sensation of real and non-penetrating sham needles.

The Biological Safety of Stainless Steel Needles Used in Warm-needling.

Warm-needling (also called thermo-acupuncture) is a combination of acupuncture and moxibustion. Due to the intense heat involved, there have been concerns over the biological safety of the acuneedles used in the treatment. This paper reports two phases of a safety test. For a preliminary test, we compared the temperature change patterns of stainless steel (SS304) needles and traditional gold alloy needles, which have been increasingly replaced by the former. To verify the effects of the presence of coating materials, the main test involved three different kinds of SS304: silicone-coated, salicylic acid-coated and non-coated needles. Each group of needles was tested for pH level, heavy metals and UV absorbance spectrum along with biological tests on the cytotoxicity and hemolysis of the needle. All the tests on the extractants from the needles were negative. In the biological tests, each test result showed a significant difference from the positive control samples, while no significant difference was observed compared with the negative control samples. In the hemolysis tests, all samples satisfied the Korean Government Standards. All the results suggest that SS304 needles are biologically safe to be used in warm-needling, though they can be improved to perform as well as the gold alloy needles in terms of temperature fluctuations.

Warm needle acupuncture at Pungsi (GB31) has an enhanced analgesic effect on formalin-induced pain in rats.

Warm needle acupuncture (WNA) therapy combines the effects of acupuncture and heat produced by moxibustion. This therapy has been widely used in Korean traditional medicine to treat a number of health problems. We evaluated the analgesic effect of WNA treatment on formalin-induced pain behavior and c-Fos expression in the spinal cord of rats. Acupuncture and heat stimulation by moxibustion were performed at the Pungsi (GB31) acupoint. Needle insertion without heat stimulation (ACU) and heat stimulation without needle insertion (SWNA) were used as negative controls. WNA therapy was executed by burning 1.5 g of cylinder-shaped moxa on top of the needle that was inserted at the acupoint. We measured temperatures of two different locations on the needle using an automatic temperature-acquisition system. Needle temperatures were overwhelmingly dependent on the distance from moxa while burning and showed a maximum of 44.9 degrees C at the location 7 mm apart from the ground after ignition. WNA treatment was more effective than ACU or SWNA in alleviating pain during the late phase in the rat formalin test. WNA, ACU, and SWNA significantly reduced c-Fos expression in the superficial dorsal horn by 23.5, 28.3 and 19.4%, respectively.

Thermal properties of direct and indirect moxibustion.

Moxibustion therapy chiefly utilizes heat generated by the combustion of moxa. Therefore, understanding the thermal properties of moxibustion is essential when studying the mechanisms involved in moxibustion therapy. Therefore, we measured temperatures of direct and indirect moxibustion. For indirect moxibustion, moxibustion on garlic was used. To determine the influence of the environment on moxibustion, we applied airflow of 0.0-0.8 m/s. An increase in the airflow caused a concomitant increase in the maximum temperature of direct moxibustion, from 160 to 300 degrees C and the time duration was reduced by half. However, the maximum temperature of indirect moxibustion demonstrated the opposite effect, with the temperature decreasing from 45 to 40 degrees C. This is attributed to the upstream airflow, which indicates the importance of the air inside moxa. For indirect moxibustion using garlic slices of different thicknesses, we found the optimum condition for the buffer layer of a garlic slice. The maximum number of consecutive moxibustions using one garlic slice was three. These results are consistent with traditional methods. This observation illustrates that the importance of garlic slices in modulating the combustion heat and proper thermal stimulus to the patient.

Individual differences of acupuncture analgesia in humans using cDNA microarray.

A large amount of evidence suggests that acupuncture stimulation enhances the experimental pain threshold in various animal models. Acupuncture analgesia is mediated by the endogenous opioid system, and the analgesic response to acupuncture shows individual variation. This study identified and characterized the genes that differ between high responders (HR) and low responders (LR) on acupuncture stimulation, using a cDNA microarray. Fifteen participants were stimulated at the LI 4 acupuncture point, and the finger withdrawal latency (FWL) test was performed to classify the HR and LR groups. Total RNA was then extracted from blood samples from each group and used as a template to synthesize cDNA. The cDNA was applied to Code Link UniSet Human 20K microarray chips. The Symptom Checklist 90-Revised (SCL-90-R) was also analyzed as a measure of psychological variation. The FWL was significantly elevated in the HR group after acupuncture stimulation, whereas there was little increase in the LR group. The ratio of HR to LR subjects was 9:6. We found that 353 and 22 genes were up- and downregulated, respectively, in the HR group. However, the SCL-90-R profiles did not differ significantly between the two groups. These results suggest that the individual variation in acupuncture analgesia, verified by measuring the FWL in the HR and LR groups, resulted from genetic inheritance rather than differences in the psychological environment.

Left-right and Yin-Yang balance of biophoton emission from hands.

Yearlong measurements of biophotons from palm and back of hand of three healthy people were performed. The detection of biophoton was done with two photomultiplier tubes whose spectral range was from 300 nm to 650 nm. The measurement was done on a circular area of diameter 46 mm whose centers were at the acupuncture point Laogong (PC8) of a palm and the mid-point of a back, respectively. The emission rates from the dorsa showed strong seasonal dependence which is consistent with the active nature of Yang meridians, while the palm sides show less seasonal dependence as they belong to the passive Yin meridians. This could be quantified simply by the standard deviations from the yearly average: They were 47.6 counts per second (cps), 66.1 cps and 66.0 cps from the dorsa, and 23.8 cps, 29.7 cps and 30.4 cps from the palms of subject 1, 2 and 3, respectively. Biophoton emission revealed qualitative individual tendencies: The subjects 1 and 2 emitted more strongly from the left dorsa, while the subject 3 from the right dorsum. The left-right balance of biophoton emission was well kept for normal people, which is in contrast with the severe imbalance for some stroke patients. Thus biophoton measurement has a diagnostic potential that encourages more studies.