Induced Cough as Predictor for Superior Laryngeal Nerve Injection- choose RIGHT(?)

Introduction: Chronic cough (CC) is a debilitating condition often involving the vagus nerve, with the superior laryngeal nerve (SLN) implicated as the sensory branch initiating the cough reflex. Steroid injections targeting the SLN have proven effective; however, the optimal side for injection remains undetermined, often leading to arbitrary decisions when initial treatments fail. This study aimed to identify the optimal side for injection to improve treatment precision.

Methods: The injection site was selected using a systematic algorithm. External laryngeal tapping was followed by laryngoscopy, during which the larynx was probed to elicit induced cough (IC) localized to the right, left, or posterior cricoid (midline). Additional ear probing, via Arnold’s nerve, was performed to elicit IC reflexes. A retrospective chart review assessed outcomes using this method, with the Cough Severity Index (CSI) measuring treatment response.

Results: Six patients were included. In four cases, the appropriate side was successfully identified, resulting in complete cough resolution. One patient with IC localized to the posterior cricoid required two injections due to dual innervation, while one patient without elicitable IC did not benefit from treatment. Overall, CSI scores improved from 22 to 12, with scores dropping to 0 in patients with successful IC localization.

Conclusions: SLN injection is a highly effective treatment for CC when IC can be elicited to guide the injection site. High satisfaction and success rates were observed in these cases. In the absence of IC, SLN injection should be avoided to prevent suboptimal outcomes.