Prospective Study of Long-Term Outcomes and the Patient Experience With Superior Laryngeal Nerve Block for Chronic Cough.

Abstract

To characterize long-term response rates to the superior laryngeal nerve (SLN) block in a prospective fashion. Secondary objectives are to provide objective data to answer common pre-procedural questions and to identify factors that predict injection outcomes. Prospective study from April 2021 to August 2024 of adult patients with refractory chronic cough undergoing SLN block. Response was measured via a yes/no question about improvement, cough severity index (CSI), and a 1-10 Likert scale grading cough impact on quality of life (QoL) taken at baseline, 2 weeks, and 6-9 months post-injection. One hundredtwenty-two patients were injected for cough, representing 249 injections. At 2 weeks after injection, 63.1% endorsed improvement on yes/no questioning ("initial improvers"), with significant improvement in both CSI and QoL scores (p < 0.001 for each). Of the initial improvers, 53.2% reported ongoing symptom improvement at long-term follow-up (6-9 months). Improvement occurred at an average of 4.3 days after injection and averaged 4.1 months in duration. 72.1% of improvers reported their degree of improvement as "a lot" or "completely." Side effects occurred in 44.2% of injections and were typically mild. No cough feature or clinical factor significantly predicted a positive response to the SLN block. This prospective assessment indicates that nearly 2 in 3 refractory chronic cough patients respond positively to SLN block, with ~50% of these initial improvers endorsing ongoing improvement at long-term follow-up. Average duration of benefit is 4 months, and side effects are common. Predictive factors of a positive response to SLN block remain undefined.