Acupuncture is a form of Eastern medicine that has been practiced for centuries. Despite its long history and worldwide application, the biological mechanisms of acupuncture in relieving pain have been poorly defined. Recent studies in mice, however, demonstrate that acupuncture triggers increases in interstitial adenosine, which reduces the severity of chronic pain through adenosine A1 receptors, suggesting that adenosine-mediated antinociception contributes to the clinical benefits of acupuncture. We asked here whether acupuncture in human subjects is also linked to a local increase in interstitial adenosine concentration. We collected microdialysis samples of interstitial fluid before, during, and after delivering 30 minutes of conventional acupuncture in the Zusanli point in human subjects. The interstitial adenosine concentration increased significantly during acupuncture and remained elevated for 30 minutes after the acupuncture. Acupuncture-mediated adenosine release was not observed if acupuncture was not delivered in the Zusanli point or if the acupuncture needle was inserted, but not rotated. This study strengthens the role of adenosine in acupuncture-mediated antinociception by directly providing such evidence in humans.

Although pulsed radiofrequency treatment (PRFT) has been used to treat trigeminal neuralgia (TN) safely, satisfactory improvement is lacking. Recently, much attention has been paid to the PRFT dose and intra-operative parameters. It has been reported that high-voltage PRFT could significantly reduce discogenic pain. However, there is no study investigating the effects of high-voltage PRFT on TN. The aim of this prospective, randomized, double-blinded study was to evaluate the efficacy and safety of high-voltage PRFT in comparison with standard-voltage PRFT for idiopathic TN. Sixty severe TN patients were randomly assigned to 2 groups treated with CT-guided standard- or high-voltage-pulsed radiofrequency (RF) of Gasserian ganglion, respectively, between January 2012 and July 2012. Numeric Rating Scales (NRS), carbamazepine dose, and side effects were evaluated at day 1, weeks 1 and 2, months 1, 3, and 6, and 1 year postoperative. There were 27 patients in the standard-voltage group and 26 patients in the high-voltage group who completed the 1-year follow-up study. The effective rates in the standard-voltage and high-voltage PRFT groups were 41% and 69%, respectively, at 1, 3, and 6 months postoperative (P = 0.037). The effective rate in the standard-voltage group decreased to 19% at 1-year postoperative, while in the high-voltage group remained at 69% (P = 0.000). No significant side effects were detected in both groups. In conclusion, CT-guided high-voltage PRFT is an effective and safe interventional therapeutic choice for idiopathic TN patients.

We retrospectively analyzed the reasons for ineffective pain relief in patients with idiopathic trigeminal neuralgia (TN) who had undergone pulsed radiofrequency (PRF) treatment guided by computed tomography scan. We found that intraoperative PRF output voltage and electrical field intensity was significantly higher (p < 0.05) in the group who had received effective treatment than in the ineffective group. These findings suggest that optimizing PRF parameters and increasing the intraoperative output voltage (electric field intensity) may therefore, provide better pain relief in patients with TN.