A Randomized clinical trial comparing the efficacy of ultrasound-guided erector spinae block and paravertebral block in preventing postherpetic neuralgia in patients with zoster-associated pain

The treatment for postherpetic neuralgia (PHN) continues to be challenging in clinical pain management. Paravertebral block (PVB) and erector-spinae block (ESPB) are two novel techniques for treating this distressing condition. We aimed to assess the effectiveness of PVB and ESPB in preventing the progression to PHN in patients with acute herpes zoster (AHZ). Sixty patients in pain due to AHZ were selected for a prospective randomized control study after approval from Institutional Ethical Committee. Written informed consent was taken. Patients were randomized and allotted into Control-group: standard treatment (oral antivirals, analgesics, neuropathic medicines); PVB-Group: standard treatment with PVB and ESPB- Group: standard treatment with ESPB. Under ultrasound guidance, both blocks were administered with 20 ml of 0.25% bupivacaine + dexamethasone 8 mg. Efficacy was evaluated on the 15th, 30th, and 60th day post treatment. The primary endpoint was the proportion of patients with adequate relief from pain and allodynia post study. The incidence of PHN post study was 45% in the ESPB group and 40% in the PVB group and 80% in the control group (p = 0.022). The proportion of patients with pain relief was higher among the PVB group compared to the ESPB group but not statistically significant (p 0.749). On day 60, the mean pain score was 2.45 (±3.05) and 2.15 (±2.7) in ESPB and PVB groups, respectively, and 4.3 (±2.27) in the control group (p 0.003). PVB and ESPB are effective approaches in treating patients suffering from pain due to acute zoster and help in preventing its progression to PHN.