Effect and safety profile of topical lidocaine on post-surgical neuropathic pain and quality of life: A systematic review and meta-analysis

STUDY OBJECTIVE: Post-surgical chronic pain with a neuropathic component is usually more severe and leads to worse quality of life. We conducted this systematic review to examine the evidence of topical lidocaine for post-surgical neuropathic pain. DESIGN: Systematic review with meta-analysis. SETTING: Published randomized controlled trials (RCTs) comparing topical lidocaine with placebo or no topical lidocaine for post-surgical neuropathic pain. PATIENTS: Seven RCTs including 585 patients. INTERVENTIONS: We systematically searched databases for randomized controlled trials (RCTs) investigating the effect and safety outcomes of topical lidocaine compared with placebo or no intervention. MEASUREMENTS: We conducted meta-analyses to evaluate the effect of topical lidocaine on pain intensity, adverse events, and quality of life. Standardized mean difference (SMD) and relative risk (RR) with 95% CIs were effect measures for continuous and dichotomous outcomes, respectively. We assessed the risk of bias of included trials and the certainty of evidence for each outcome. MAIN RESULTS: Our review included 7 studies with 585 participants. There is moderate certainty evidence that topical lidocaine may increase the likelihood of global pain relief, with a relative risk (RR) of 1.98 (95% confidence interval (CI): 1.04, 3.76; I² = 70%, P = 0.04). Low certainty evidence suggested topical lidocaine may lead to more reduction in pain intensity (SMD: -0.70; 95% confidence interval: -1.46, 0.06; I² = 93%, P = 0.07). High certainty evidence showed that topical lidocaine did not increase the adverse event risk (RR: 1.04; 95% CI: 0.93, 1.16; I² = 0%, P = 0.51). CONCLUSIONS: Topical lidocaine may lead to pain relief and is safe to use for patient with post-surgical pain, though its impact on quality of life is unclear. This review supports the use of topical lidocaine for patients with post-surgical pain, and reveals the evidence gap in topical lidocaine use. (Registration: PROSPERO CRD42021294100).