Effects of continuous epidural block combined with oral analgesics for the treatment of patients with herpes zoster related pain in the lower limb during subacute period

Abstract

Objective To explore the safety and efficacy of continuous epidural block combined with oral analgesics for the treatment of patients with herpes zoster related pain in the lower limb during subacute period. Methods Seventy-three patients with herpes zoster related pain in the lower limb persisted more than 1 month from December 2015 to December 2017 in Wuhan First Hospital were analyzed. The patients were divided into 2 groups randomly: continuous epidural block group (n=38) and oral drug group (n=35). Epidural catheter was connected to continuous analgesic pump contained 70 ml 2% lidocaine diluted to 180 ml with 0.9% normal saline at the infusion rate of 3 ml/h for 5 d, and combined with oral gabapentin capsules, 600 mg/time, 3 times a day, and tramadol 0.1g, every 12 hours in the continuous epidural block group. Only oral medication was taken in the oral drug group. Izbicki pain score system and self-rating anxiety scale (SAS) were used to assess pain control and anxiety before the treatment, and 7 days, 3 months and 6 months after the treatment. According to the time of pain persisting, the continuous epidural block group was classified into two subgroups: subgroup 1(pain persisting between 1 and 3 months, subacute phase, n=26); subgroup 2 (pain persisting more than 3 months, postherpetic neuralgia, n=26). European Organization for Research and Treatment of Cancer (EORTC) was used to evaluate the quality of life at 6 months after the treatment. Results Pain scores (visual analogue scale, frequency of pain attacks, and inability to work) were significantly lower in continuous epidural block group than those in the oral drug group (P 0.05) between the two groups. However, the dosage of analgesic medication was lower in continuous epidural block than that in oral drug group at 6 months (P<0.05). Also, Anxiety status was satisfactory control in continuous epidural block group. Additionally, visual analogue scale of pain, frequency of pain attacks, analgesic medication used, and inability to work were significantly higher in subgroup 2 (PHN group) than those in subgroup 1 at 6 months after the treatment (P<0.05). All the functional scales of EORTC-QLQ-C30 were higher in subgroup 2 (PHN group) than those in subgroup 1 (P<0.05). In the symptom scales, pain, insomnia, loss of appetite were higher in subgroup 2 (P<0.05). Conclusion Continuous epidural block combined with oral analgesics can effectively relieve pain symptoms and anxiety status of the patients with herpes zoster related pain whose pain persisted 1 to 3 months. However, this effect is limited for PHN patients in pain control and the quality of life improvement. Key words: Anesthesia, epidural; Herpes zoster; Lower extremity; Time factors