Eugenol inhibits the GABAA current in trigeminal ganglion neurons.

Eugenol has sedative, antioxidant, anti-inflammatory, and analgesic effects, but also serves as an irritant through the regulation of a different set of ion channels. Activation of gamma aminobutyric acid (GABA) receptors on sensory neurons leads to the stabilization of neuronal excitability but contributes to formalin-induced inflammatory pain. In this study, we examined the effect of eugenol on the GABA-induced current in rat trigeminal ganglia (TG) neurons and in human embryonic kidney (HEK) 293 cells expressing the GABAA receptor α1ß2γ2 subtype using the whole-cell patch clamp technique. RT-PCR and Western blot analysis were used to confirm the expression of GABAA receptor γ2 subunit mRNA and protein in the TG and hippocampus. Eugenol decreased the amplitude ratio of the GABA-induced current to 27.5 ± 3.2% (p < 0.05) in TG neurons, which recovered after a 3-min washout. In HEK 293 cells expressing the α1ß2γ2 subtype, eugenol inhibited GABA-induced currents in a dose-dependent manner. Application of eugenol also decreased the GABA response in the presence of a G-protein blocker. Eugenol pretreatment with different concentrations of GABA resulted in similar inhibition of the GABA-induced current in a non-competitive manner. In conclusion, eugenol inhibits the GABA-induced current in TG neurons and HEK 293 cells expressing the GABAA receptor in a reversible, dose-dependent, and non-competitive manner, but not via the G-protein pathway. We suggest that the GABAA receptor could be a molecular target for eugenol in the modulation of nociceptive information.

An alternative distal approach for the lumbar medial branch radiofrequency denervation: a prospective randomized comparative study.

BACKGROUND: An alternative technique involving a "distal approach" can be used for lumbar medial branch radiofrequency denervation (LMBRFD). We described and assessed this technique by comparing it with a conventional tunnel vision approach in a prospective randomized trial. METHODS: Eighty-two patients underwent LMBRFD by a distal (n = 41) or a tunnel vision approach (n = 41). The primary end point was a comparison of the mean difference in the change of 11-point numeric rating scale (NRS) scores of low back pain from entry to the scores at 1 month (NRS at baseline--NRS at 1 month) and at 6 months (NRS at baseline--NRS at 6 months) between the distal approach group and the tunnel vision approach group. The secondary end points were a change of NRS and the Oswestry disability index over time. RESULTS: Thirty-four patients in each group had complete time courses. There were no statistically significant differences in the change of NRS scores between the groups at 1 month (corrected P = 0.19; 97.5% 2-sided confidence interval [CI], -1.37 to 0.37) and 6 months (corrected P = 0.53; 97.5% CI, -1.36 to 0.77). Patients in both groups showed a statistically significant reduction in NRS and Oswestry disability index scores from baseline to that of the scores at 1 and 6 months (all P < 0.0001, Bonferroni corrected). The procedure-related pain score was significantly lower in the distal approach group (P = 0.001; 99% CI, -2.00 to -0.23). CONCLUSIONS: Patients who underwent LMBRFD by the tunnel vision or distal approaches showed significant pain relief at the 6-month follow-up. Less periprocedural pain was reported in the distal approach group. We consider that the distal approach provides an improved option for LMBRFD.

Psychometric characteristics of the Korean version of the Roland-Morris Disability Questionnaire.

The aims of this study were; 1) to develop the final version of the Korean Roland-Morris Disability Questionnaire (RDQ), and 2) to compare the responsiveness between the RDQ and the Oswestry Disability Index (ODI) scores in patients having low back pain. The psychometric properties of the final Korean RDQ were evaluated in 221 patients. Among them, 30 patients were reliability tested. Validity was evaluated using an 11-point numerical rating scale (NRS) and the Korean ODI. The receiver operating characteristic (ROC) curve analysis of the RDQ and the ODI was compared in 54 patients with lumbar zygapophyseal (facet) joint pain. There was a moderate relationship between the RDQ and NRS (r = 0.59, P < 0.01) and a strongly positive correlation between the RDQ and the ODI (r = 0.76, P < 0.001). The Korean RDQ with the higher area under the ROC curve showed a better overall responsive performance than did the ODI in patients with lumbar facet joint pain after medial branch radiofrequency neurotomy (P < 0.01). The results of the study present the final version of the Korean RDQ is valid for assessing functional status in a Korean population with chronic low back pain.

Bilateral femoral neuropathy after vaginal delivery: A case report.

Epidural analgesia is frequently used for the management of labor pain in parturients. The neurologic complications of epidural analgesia are rare, but they are catastrophic when they occur. We report here on a case of bilateral femoral neuropathy in a vaginal delivery patient with epidural analgesia. The patient complained of weakness of both thighs and numbness around both knees. Neurologic examination and electromyographic study revealed that they occurred due to the delivery itself. The patient had not fully recovered at eight weeks after delivery. The declining incidence of postpartum femoral neuropathy may reflect a reduced duration of labor in accordance with modern obstetric practice, and particularly the more frequent use of Caesarean delivery. The exact etiology of postpartum femoral neuropathy is unknown, and the possible factors are direct compression of nerves that are proximal within the pelvis by either the fetal head or birthing instruments, or this malady is the result of pressure induced ischemia at the level of the inguinal ligament when the pregnant woman is in the lithotomy position.