Antinociceptive effect of linear polarized 0.6 to 1.6 microm irradiation of lumbar sympathetic ganglia in chronic constriction injury rats.

Linear polarized near-infrared light created with linear polarized near-infrared light therapy equipment (Super Lizer HA-550, Tokyo Iken Co, Ltd, Tokyo, Japan) has been used for the treatment of various painful disorders in Japan. Irradiation near the stellate ganglion with a Super Lizer (ISGL) is an especially notable therapeutic method used with stellate ganglion block (SGB) or substitutes for SGB. ISGL is a safe, simple, well-tolerated, and effective treatment. We examined the effects of irradiation with a Super Lizer applied to an area near the lumbar sympathetic ganglia on the ligated side in a chronic constriction injury (CCI) model, which is believed to be an animal model of complex regional pain syndrome (CRPS). Rats showing thermal hyperalgesia in a radiant heat test 1 wk postoperatively were used in Experiments 1 and 2: (1) Thermal hyperalgesia of irradiation group (n = 11) was less than that of the control or nonirradiation (n = 11) group at 1, 3, and 8 h after irradiation; however, the effect disappeared 12 h after irradiation. (2) Daily irradiation (n = 16) and 1 wk (n = 14) from 7 days after nerve ligation significantly shortened the interval from thermal hyperalgesia until recovery. Rats showing mechanical hyperalgesia in the von Frey hair test 1 wk postoperatively were used in Experiment 3: 1 wk irradiation beginning 7 days after nerve ligation (n = 9) did not promote the recovery from mechanical hyperalgesia. We speculate that repeated ISGL may be more effective than a single ISGL in alleviating pain in CRPS patients. We cannot explain the discrepancy between the results obtained in Experiments 2 and 3. We believe the results of this study are relevant to the effect of ISGL for patients with upper-limb CRPS: irradiation near the lumbar sympathetic ganglia of the rat is effective for thermal but not mechanical pain in CCI.

Does a viral infection cause complex regional pain syndrome?

In 1990 Omura, Y. reported that Herpes Simplex Virus Type 1 as the major cause of chronic intractable pain and its effective treatment using mixture of EPA & DHA with Selective Drug Uptake Enhancement Method. Subsequently among the other causes of pain, he included Chlamydia Trachomatis, Borrelia Burgdorferi, Mycobacterium Tuberculosis, human Herpes Virus type 6, and Circulatory Disturbances. In order to test possible involvement of viral infection in Complex Regional Pain Syndrome (CRPS), a disease which usually occurs in the extremities, we did a study of 17 patients with CRPS. They were examined for Herpes Simplex Virus (HSV) and Varicella Zoster Virus (VZV) by measuring IgG and IgM antibody titers, and 14 of these patients were also examined for Cytomegalo-Virus (CMV). As a control group 100 healthy Japanese employees at SRL, Inc. were also studied. In CRPS group, HSV IgG was positive in 12 of the 17 patients with an average antibody titer of 90.0 EIA value. VZV IgG was positive in all 17 patients with an average antibody titer of 26.8 EIA value. CMV IgG was positive in all 14 patients with an average antibody titer of 66.6 UA/ml. In control group, HSV IgG was positive in 54 subjects with an average antibody titer of 42.3 EIA value. VZV IgG was positive in 97 subjects with an average antibody titer of 26.2 EIA value. CMV IgG was positive in 82 subjects. There were no significant differences of positive rate of IgG antibody for the three viruses between patient and control groups. Although the difference was not significant, the average antibody titers of HSV in CRPS group were more than twice of those in healthy group. Antibody titers were almost equal in both groups for VZV. Possibly, some people in the control group who had latent virus, were also asymptomatic. In 2000, Takasaki, I. et al. in a separate animal study, inoculated with HSV Type-I the shin of the mouse causing allodynia and hyperalgesia (which are some of the characteristic findings seen in CRPS in humans). Also, VZV, which causes shingles which is sometimes followed by Post-Herpetic Neuralgia (PHN), is in the same family of HSV. As PHN resembles CRPS in symptoms, it is possible that HSV contributes to CRPS. Therefore, virus infection theory is an attractive hypothesis that accounts for many enigmas of CRPS.