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 postsurgical 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 postsurgical pain, and reveals the evidence gap in topical lidocaine use. (Registration: PROSPERO CRD42021294100).