Objective: This study was to evaluate the effectiveness of ultrasound-guided percutaneous ozone injections around the cervical dorsal root ganglions of zoster-associated pain (ZAP) patients.
Study design: Retrospective comparative study.
Settings: The study was conducted at a pain center of a university hospital.
Patients and methods: From June 2016 to July 2017, a total number of 30 patients with ZAP were treated with ultrasound-guided percutaneous ozone injection around the cervical dorsal root ganglion (DRG) at the injured nerve level (C2-C8). A volume of 3 mL ozone-oxygen mixture at a concentration of 30 µg/mL was injected into the area around the DRG. Patients were divided into two groups according to their disease duration: group A (at or <3 months) and group B (>3 months). The pain severity was assessed according to a visual analog scale, and imaging changes were evaluated by ultrasound. Patient improvements in pain and neurologic function were evaluated during a follow-up period from 1 to 3 months.
Results: The data showed that ozone injections reduced pain in patients with ZAP. However, the success rate of group A was higher than group B. After the injection, the von Frey data demonstrated decreases in both groups, but, there were no significant differences between the groups. Moreover, univariate logistic regression analysis and multivariate regression analysis showed a history of diabetes mellitus had a significant effect on the treatment results.
Conclusions: Percutaneous ozone injection around the DRG might be a useful method for treatment-resistant cases of ZAP at the cervical level. Institutional Review Board (IRB) approval number: HK2017-1130.
Keywords: herpes zoster, neuropathic pain, post-herpetic neuralgia, ozone injection