Superior Laryngeal Nerve Block Response Rates in 54 Neurogenic Cough Patients

Neurogenic cough related to hypersensitivity of the internal branch of the superior laryngeal nerve (SLN) is often treated with neuromodulating medications, which can cause considerable side effects. An alternative therapy is steroid and local anesthetic injection of the SLN ("SLN block"), initially proposed to benefit those with lateralizing symptoms (tenderness over the thyrohyoid membrane or unilateral cough source). Our objectives are to determine if SLN block produces subjective symptomatic improvements and if repeat injections further improve symptoms, and evaluate clinical factors potentially predictive of response.

Retrospective chart review of 54 patients receiving SLN blocks at a tertiary medical academic center from January 2010 to June 2020. Medical history and anticipated predictors of positive response, including stigmata of laryngeal hypersensitivity, were recorded. Outcomes included symptomatic response, number of injections required, and side effects. Response was defined subjectively by asking patients whether the injection was beneficial and objectively by using CSI scores.

Fifty-four patients met the inclusion criteria. Thirty-eight patients (70.4%) endorsed improvement. No variables were identified as positive predictors of response. Thirty-two of the 38 (84.2%) endorsed improvement after one injection. Six of 15 (40%) patients who failed the first injection had positive response to the second. No significant side effects were reported.

No localizing symptoms, specific cough features, or aspects of the medical history helped predict response, suggesting that a broader range of patients may be offered the intervention. The majority of patients reported symptomatic improvement and repeat injections may benefit patients with initial nonresponse.

4 Laryngoscope, 133:2647-2653, 2023.