Effect of Superior Laryngeal Nerve Block for Neurogenic Cough: A Single-Arm Meta-Analysis

We aimed to assess cough symptom improvement following superior laryngeal nerve block (SLNB) in patients with neurogenic cough (NC).

Studies were systematically searched on PubMed, Embase, Web of Science, and Cochrane Library.

Articles reporting SLNB for the treatment of NC were included. Outcomes of interest included subjective reporting of improvement, patient-reported outcome measures, and adverse events. Mean difference (MD) was used for continuous outcomes and proportions for binary endpoints, with 95% confidence intervals (CI).

Eight retrospective studies involving 552 patients met inclusion criteria. The pooled proportion of subjective improvement of cough following SLNB was 74.04% (95% CI 68.61-78.81, I² = 13.6%). Patients experienced a statistically significant reduction in Cough Severity Index scores (MD -7.37, 95% CI -13.42 to -1.32, P = .02, I² = 81.7%), with the greatest reduction in those who underwent 3 or more injections (MD -10.57, 95% CI -19.37 to -1.78, I² = 33.4%, P = .02). Adverse events were minimal and self-resolving, with 17.91% and 3.35% of patients experiencing local transient and systemic transient events, respectively. Injection-limiting/serious adverse events were rare, occurring in 1.97% of patients.

Our findings suggest that SLNB may benefit a substantial number of patients, as evidenced by improvements in both subjective reports and cough-specific patient-reported outcomes, while maintaining a favorable safety profile with minimal adverse events. Additionally, patients who received multiple injections generally experienced greater reductions in cough severity. Further large-scale clinical trials are needed to confirm the efficacy and long-term effects of this treatment modality.

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