Efficacy and safety of the extracorporeal shockwave therapy in patients with postherpetic neuralgia: study protocol of a randomized controlled trial

BACKGROUND: Postherpetic neuralgia (PHN) is one of the most common types of chronic neuropathic pain, which seriously affects quality of the life because of pain severity and poor response to the currently available treatments. The main strategies for PHN management are medication and invasive interventional therapies; however, these approaches have many adverse effects, so it is important to find another effective and safe treatment for PHN. METHODS: A single-center, single-blind randomized clinical trial will evaluate 98 study participants randomized in a 1:1 ratio into control and experimental groups. The control group will receive conventional treatment including medication therapy and invasive interventional therapy. The experimental group will receive extracorporeal shockwave therapy (ESWT) in addition to conventional therapy. The primary outcome is pain intensity assessed on a visual analogue scale (VAS); the secondary outcomes are the following: quality of life assessed by the 36-Item Short-Form Health Survey (SF-36), psychological state for anxiety and depression measured by the Self-Rating Anxiety Scale (SAS) and Self-Rating Depression Scale (SDS), and sleep quality measured by the Pittsburgh Sleep Quality Index (PSQI). Assessors blinded to the randomization will collect data during the intervention period at baseline and weeks 1, 4, and 12. The plasma levels of tumor necrosis factor-α and interleukin-6 will be assessed before and after ESWT to explore the biochemical mechanisms of ESWT in the treatment of PHN. DISCUSSION: This randomized controlled trial will evaluate the effectiveness and safety of ESWT in patients with PHN and thus will provide clinical evidence for its use in the management of PHN and explore the potential biochemical mechanisms of this treatment. TRIAL REGISTRATION: www.ChiCTR.org.cn, identifier: ChiCTR1900025828. Registered on 10 September 2019