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.

Intravenous regional block with lidocaine for treatment of complex regional pain syndrome.

OBJECTIVES: The goal of this article is to report the successful treatment of a patient with complex regional pain syndrome (CRPS) type 1 involving the hand with the use of an intravenous regional block. METHODS: The patient was a 35-year-old woman who developed CRPS during conservative therapy for a metacarpal fracture. An intravenous regional block with lidocaine alone, using a two-tourniquet technique, was delivered 10 times for at least 40 minutes. The first five treatments were given twice a week and the next five were delivered weekly. All affected joints, including the wrist, were manipulated without undue force. Functional physical measurements were assessed, including range of motion and performance of fine and gross motor tasks. RESULTS: The visual analog scale scores for pain declined from 10 to 0 after treatment. Use of a pen, a pair of chopsticks, and a hammer improved, and edema decreased. CONCLUSIONS: Intravenous regional block with lidocaine was well tolerated and associated with relief in this case of CRPS type 1.

Basal blood flow in complex regional pain syndrome does not necessarily indicate vasoconstrictor nerve activity.

OBJECTIVES: To quantitatively investigate simultaneous skin blood flow and sweating in a patient with complex regional pain syndrome. METHOD: Using one probe, skin blood flow and sweating were measured on the affected and non-affected sides at baseline and after activation of sympathetic system in a 47-year-old woman with complex regional pain syndrome type I of the left hand. RESULTS: Basal sweating, sympathetic sweat response, basal blood flow, sympathetic flow response, and attrition rate of blood flow (the ratio of sympathetic flow response to basal blood flow) of the affected side were greater than those on the non-affected side. CONCLUSIONS: Although sympathetic nerve activity (sympathetic flow response) appeared greater on one side, basal blood flow was also greater on that side. These contradictory results suggest that some factor or factors increase basal blood flow despite a higher sympathetic nerve tone on the side. Comparing basal blood flow on one side to the contralateral side does not necessarily indicate lesser vasoconstrictor nerve activity on that side. Advantages of simultaneous measurement of skin blood flow and sweating with a single probe may make the method useful.

Comparison of current perception threshold between each side in unilateral complex regional pain syndrome patients does not measure the patient's pain.

The current perception threshold (CPT) test has been developed as one of the neuroselective sensory nerve conduction threshold tests. The score of the CPT of the affected side subtracted from the score of the CPT of the unaffected side in complex regional pain syndrome (CRPS) is expected to show pain objectively. The purpose of this study is to examine first whether the CPT of the affected side is generally lower than that of the unaffected side, and second, whether the greater score shows the more intense pain. The CPT of each side in 25 patients with unilateral CRPS type I was measured and compared. For the 2000 Hz stimulus, the CPT of the affected side was 2677 +/- 262 microAmp (mean +/- standard error) and the CPT of the unaffected side was 2194 +/- 247 microAmp (p = 0.0149). For the 250 Hz stimulus, the CPT was 876 +/- 117 microAmp and 721 +/- 73 microAmp respectively (p > 0.05). For the 5 Hz stimulus, the CPT was 730 +/- 105 microAmp and 448 +/- 56 microAmp respectively (p = 0.0018). In 2000 Hz, 250 Hz, and 5 Hz stimuli, the CPT of the affected side was higher than that of the unaffected side. This shows that generally the affected side is less sensitive than the unaffected side in terms of current perception. The score of the CPT of the affected side subtracted from the score of the CPT of the unaffected side in CRPS does not measure the patient's pain.

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.