Effects of applying nerve blocks to prevent postherpetic neuralgia in patients with acute herpes zoster: a systematic review and meta-analysis

Abstract

BackgroundPostherpetic neuralgia (PHN) is a common and painful complication of acute herpes zoster. In some cases, it is refractory to medical treatment. Preventing its occurrence is an important issue. We hypothesized that applying nerve blocks during the acute phase of herpes zoster could reduce PHN incidence by attenuating central sensitization and minimizing nerve damage and the anti-inflammatory effects of local anesthetics and steroids.MethodsThis systematic review and meta-analysis evaluates the efficacy of using nerve blocks to prevent PHN. We searched the MEDLINE, EMBASE, Cochrane Library, ClinicalTrials.gov and KoreaMed databases without language restrictions on April, 30 2014. We included all randomized controlled trials performed within 3 weeks after the onset of herpes zoster in order to compare nerve blocks vs active placebo and standard therapy.ResultsNine trials were included in this systematic review and meta-analysis. Nerve blocks reduced the duration of herpes zoster-related pain and PHN incidence of at 3, 6, and 12 months after final intervention. Stellate ganglion block and single epidural injection did not achieve positive outcomes, but administering paravertebral blockage and continuous/repeated epidural blocks reduced PHN incidence at 3 months. None of the included trials reported clinically meaningful serious adverse events.ConclusionsApplying nerve blocks during the acute phase of the herpes zoster shortens the duration of zoster-related pain, and somatic blocks (including paravertebral and repeated/continuous epidural blocks) are recommended to prevent PHN. In future studies, consensus-based PHN definitions, clinical cutoff points that define successful treatment outcomes and standardized outcome-assessment tools will be needed.

Decreased absolute numbers of CD3+ T cells and CD8+ T cells during aging in herpes zoster patients

“…PHN is a ubiquitous sequelae after HZ infection that severely affects patient quality of life 32 . To date, the mechanism involved in the development of PHN remains unknown.…”

Comparison of the Analgesic Effect of Ropivacaine with Fentanyl and Ropivacaine Alone in Continuous Epidural Infusion for Acute Herpes Zoster Management: A Retrospective Study

“…Therefore, active treatment before the nerve damage occurs can help prevent PHN and control pain. A recent meta-analysis reported that CEI in the acute phase of HZ is effective in controlling pain and preventing PHN [14]. The rationale behind using CEI to manage acute HZ pain and prevent PHN is that the interruption of afferent pain stimuli to the central nervous system and the improved blood flow to nerve tissue will minimize neural damage and reduce pain to the patient by blocking sympathetic nerves [15,16].…”

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

“…Therefore, proactive treatment before nerve injury can help prevent PHN. According to a recent meta-analysis, continuous epidural infusion in acute herpes zoster is effective in preventing PHN [9]. The rationale behind the application of epidural blocks to control acute herpes zoster pain and prevent PHN is that the discontinued delivery of an invasive afferent stimulus to the central nervous system and improved flow of blood to the subjects' nerve tissue will minimize neural damage and reduce sensitization.…”

“…Epidural, sympathetic, and paravertebral blocks are considered active treatments for acute episodes of herpes zoster. For acute herpes zoster, continuous epidural infusion is commonly used in clinical settings and is reported to reduce the likelihood of transition to PHN via pain control [8][9][10]. For conventional continuous epidural infusion, the location of the epidural catheter is confirmed by injecting a contrast agent at the suspected epidural level, which is identified based on the site of rash or pain.…”