HZ: herpes zoster, EB: epidural block, DRP: days required for the relief of pain, DRLP: duration of the late residual pain, TDP: total duration of pain, PVB: paravertebral block, VAS: visual analogue scale, PHN: postherpetic neuralgia, SGB: stellate ganglion block, NRS: numeric rating scale, VRS: verbal rating scale.