Efficacy of Tender Point Infiltrations (TPI) in Patients with Acute and Subacute Zoster-Associated Pain: Study Protocol for a Randomized, Prospective, Multicenter, Blinded Endpoint, Open-Label Controlled Trial

Introduction: Herpes zoster (HZ) can adversely influence patients' quality of life and sometimes it can develop postherpetic neuralgia (PHN). To date, it remains challenging manage well using currently available therapies. Tender point infiltration (TPI) might have the potential to be an analgesic therapy for acute and subacute HZ pain. However, current evidence remains insufficient. Therefore, the purpose of this protocol is to design a study to: 1) evaluate the analgesia efficacy and safety of TPI for acute and subacute HZ; 2) to explore the positive predictors of TPI for prevention of PHN. Methods and Analysis: This study is designed as a randomized, prospective, multicenter, blinded endpoint, open-label controlled trial including a 12-month follow-up period. 176 qualified participants will be randomly split into the standard group or TPI group in a ratio of 1:1. Primary outcome will be the presence of PHN 12 months posttreatment. Secondary outcomes include the presence of PHN at month 3 and month 6 posttreatment. Visual Analogue Scales (VAS) for assessment of pain, consumption of oral analgesia drugs, patient satisfaction scores on the 5-point Likert scale, patients' quality of life scored on the WHOQOL-BREF at day 1, week 2, month 1, month 3, month 6 and month 12, proportion of patients receiving repeated TPIs and block points each time for TPI group. Multivariable logistic analyses will be performed to identify predictive factors for the prevention of PHN at month 12 after treatment. Safety evaluation will be determined by adverse events during the trial.