To evaluate the therapeutic effect of high-voltage long-duration bipolar pulsed radiofrequency (PRF) radiotherapy on postherpetic neuralgia (PHN) by measuring temperature shift on abnormal skin with infrared thermography and examining mood improvement with depression scale.

Thirty patients suffered from herpes zoster on the torso for 2-4 months were enrolled in this study. Demographic data of these patients were collected. Preoperative pain symptoms and mood status were respectively assessed with VAS and Hamilton Depression Scale-17 (HAMD-17). Infrared thermograph of the lesioned skins were taken and the temperature differences between the lesioned and the normal skins were analyzed. The standard 600 s high-voltage (50-70 V) long-duration (30 ms) bipolar pulsed radiofrequency (3 Hz) radiotherapy was performed under the guidance of CT. The VAS scores, thermographs and HAMD-17 scores were recorded after radiotherapy.

In a total of 30 patients, the VAS were significantly reduced 1 and 3 days after radiotherapy (P<0.05). The VAS were increased to the preoperative levels 7 and 14 days after radiotherapy (P>0.05). The infrared thermography showed that the temperature was (0.53±0.28) °C higher in lesioned area than in healthy area, but the difference was significantly reduced 1 and 3 days after radiotherapy[1 day: (0.27±0.22) °C, 3 days: (0.28±0.24) °C]. Preoperative HAMD-17 scores in 24 out of 30 patients were greater than 17 and did not change after operation. Interestingly, there was a significant correlation between VAS and HAMD-17 scores before (P=0.006, r=0.492) and after operation (P=0.023, r=0.872).

After 1 and 3 days treatment, high-voltage long-duration bipolar pulsed radiofrequency radiography relieved pain symptoms, reduced temperature in abnormal skin, but did not improve moods, in patients suffered from postherpetic neuralgia.

Thermal imaging; Bipolar pulsed radiofrequency treatment; Neuralgia, postherpetic; Depression