Modified In-Office Superior Laryngeal Nerve Steroid Injection Technique for the Treatment of Chronic Cough

Objectives: To compare an endoscopically guided, modified in-office internal superior laryngeal nerve (iSLN) percutaneous steroid injection technique with a traditional landmark-guided percutaneous approach for refractory chronic cough. Methods: Single-centre retrospective comparative cohort study of those with chronic cough >8 weeks adjudicated as neurogenic/hypersensitivity-related after structured evaluation and management of common aetiologies. Consecutive patients treated at a tertiary laryngology service from January 2021 to January 2025 were identified. Patients underwent either landmark-guided percutaneous iSLN block (unmodified) or iSLN percutaneous block under flexible nasolaryngoscopic visualisation (modified), enabling real-time confirmation of needle position and routine bilateral treatment with partial superficial laryngeal mucosal instillation. Primary outcome was patient-reported improvement (Y/N; 1-10 severity scale). Secondary outcomes included Leicester Cough Questionnaire, Cough Severity Index, Newcastle Laryngeal Hypersensitivity Questionnaire, Reflux Severity Index, Voice Handicap Index-10, repeat procedures, and adverse events. Results: Of 142 patients (median age 62.8 years; 75% female), 65 underwent landmark-guided injection and 77 underwent the modified endoscopically guided technique. At most recent follow-up, global improvement was reported by 84.4% (65/77) in the modified cohort versus 47.7% (31/65) in the unmodified cohort. Median symptom reduction was greater with the modified approach (77.8% (IQR 61.3-86.6)) than among unmodified responders (50.3% (IQR 25.0-75.0)). Across all validated patient-reported outcome measures, the modified technique demonstrated more pronounced improvement than the landmark-guided approach. Minor adverse events were uncommon (modified = 6.5%, unmodified = 4.6%). Conclusions: Endoscopically guided modified iSLN steroid injection with routine bilateral targeting is associated with greater patient-reported improvement and superior validated cough outcomes than landmark-guided injection, without added significant risk.