Efficacy of continuous epidural infusion with epidural electric stimulation compared to that of conventional continuous epidural infusion for acute herpes zoster management: a retrospective study

Background Continuous epidural infusions are commonly used in clinical settings to reduce the likelihood of transition to postherpetic neuralgia via pain control. The purpose of this study was to compare the efficacy of conventional continuous epidural infusion to that of continuous epidural infusion in which the catheter is guided by electric stimulation to areas with neurological damage for the treatment of zoster-related pain and prevention of postherpetic neuralgia. Methods We analyzed the medical records of 114 patients in this study. The patients were divided into two groups: contrast (conventional continuous epidural infusion) and stimulation (continuous epidural infusion with epidural electric stimulation). In the contrast group, the position of the epidural catheter was confirmed using contrast medium alone, whereas in the stimulation group, the site of herpes zoster infection was identified through electric stimulation using a guidewire in the catheter. Clinical efficacy was assessed using a numerical rating scale (pain score) up to 6 months after the procedures. We compared the percentage of patients who showed complete remission (pain score less than 2 and no further medication) in each group. We also investigated whether the patients required additional interventional treatment due to insufficient pain control during the 6-month follow-up period after each procedure. Results After adjusting for confounding variables, the pain score was significantly lower in the stimulation group than in the contrast group for 6 months after the procedure. After adjustment, the odds of complete remission were 1.9-times higher in the stimulation group than in the contrast group (95% confidence interval [CI]: 0.81–4.44, P = 0.14). Patients in the contrast group were significantly more likely to require other interventions within 6 months of the procedure than patients in the stimulation group (odds ratio: 3.62, 95% CI: 1.17–11.19, P = 0.03). Conclusion Epidural drug administration to specific spinal segments using electric stimulation catheters may be more helpful than conventional continuous epidural infusion for improving pain and preventing postherpetic neuralgia in the acute phase of herpes zoster.