清水 啓介

An objective method to evaluate patient suitability for cognitive behavioral therapy (CBT) for chronic low back pain (LBP) is currently lacking. Inappropriate application can result in prolonged hospital visits and increased medical costs. Therefore, identifying an objective biomarker for evaluating suitability is crucial. This study focused on electroencephalogram (EEG) complexity as a potential biomarker for evaluating CBT suitability for chronic LBP, assessing its discriminative ability and identifying factors that impede treatment. Complexity was analyzed as multiscale fuzzy sample entropy (MFSE). Fifty patients with suspected psychosocial factors causing LBP along with 20 healthy volunteers were included. The analysis included 25 responders and 25 non-responders for CBT. MFSE showed significant effects of scale factor [F(19,171) = 14.82, p < 0.01, partial η2 = 0.622] and interaction between group and scale factor [F(38,171) = 7.34, p < 0.01, partial η2 = 0.620]. The low-frequency band MFSE score had an odds ratio of 10.768 (95% confidence interval: 8.263-10.044, p < 0.001). The low-frequency band showed a high discriminative ability (area under the curve: 0.825), with a cut-off value of 1.25. The low-frequency FMSE is a superior biomarker for predicting suitability for CBT. This method can quickly evaluate suitability, reducing the burden on medical professionals and patients, and lowering medical costs.

Background Symptoms of lumbar spinal stenosis (LSS) are associated with changes in blood flow to lower limbs. These changes in blood flow can be perceived as temperature variations, which can be visualized using thermography. We compared the relationship between the subjective symptoms of LSS and temperature variations before and after surgical intervention and investigated the associated patient factors. Methods Patients who underwent laminectomy for LSS were included. Plantar temperature was measured preoperatively and postoperatively using thermography. Subjective symptoms and patient backgrounds were assessed through interviews and medical records. Temperature differences were evaluated using the parameter ΔT, defined as the temperature of the limb with stronger symptoms minus the temperature of the limb with weaker symptoms. The analyses were performed based on these parameters. Results The symptoms improved following laminectomy, and ΔT showed a significant increase. Pain and ΔT were positively correlated preoperatively, whereas ΔT and numbness and neuropathic pain scores were negatively correlated postoperatively. Cauda equina symptoms were associated with a decrease in ΔT both preoperatively and postoperatively, whereas age and disease duration were associated with a postoperative decrease in ΔT. Conclusion The postoperative increase in ΔT, resulting from the alleviation of nerve compression, suggests a relationship between nerve dysfunction and decreased temperature. The preoperative correlation between pain and ΔT may be attributed to vasodilation mediated by calcitonin gene-related peptide. The postoperative correlation between ΔT and neurological symptoms may reflect an association between the extent of nerve damage and reduced blood flow. In particular, cauda equina symptoms may lead to decreased blood flow through dysfunction of the S region, causing a relatively sympathetic-dominant state due to impaired parasympathetic function. Our findings suggest the potential of using temperature measurements to visualize and objectively evaluate subjective symptoms.

Co-administration of mirogabalin besylate and nonsteroidal anti-inflammatory drugs is effective for neuropathic pain; however, mechanism of its action remains unknown. We aimed to evaluate the mechanism of this synergistic effect of the concomitant administration for neuropathic pain using chronic constriction injury model rats. Fifty male Wister rats of 7-week-old were used. Right sciatic nerve ligation was performed in 40 rats and they were sub-divided into four groups: vehicle, mirogabalin, diclofenac sodium and co-administration of them. Ten rats underwent sham surgery. Fluorogold was attached to sciatic nerve during surgery. Von Frey filament and weight bearing tests were performed on postoperative Day 6 as behavioral assessments and drug was administrated intraperitoneally. Half rats in each group underwent behavioral assessment and perfusion fixation using 4% paraformaldehyde on postoperative Day 7 and remaining on postoperative Day 14. Subsequently, dorsal root ganglion at L4 to L6 was collected and examined immunohistochemistry for calcitonin gene-related peptide, and their immunoreactivity in fluorogold-labeled neurons was measured. Spinal cord at lumbar swelling was resected, immunostained for ionized-calcium-binding adapter molecule-1 and glial fibrillary acidic protein, and immunoreactive neurons in dorsal horn of spinal cords were calculated as the occupancy of them. Mirogabalin suppresses the neuropeptide-release from presynaptic afferent neuron directly and it resulted in suppressing glia cells activation. Diclofenac sodium inhibits cyclooxygenase-2 and prostaglandin production, related to allodynia. These effects of mirogabalin and diclofenac sodium, respectively, inhibited glia cells strongly, which is presumed to be one of the mechanisms for the effectiveness of their co-administration for neuropathic pain.