# Validation of an Endoscopic Landmark for Injection of Internal Branch of Superior Laryngeal Nerve

## TL;DR

This study validates a new endoscopic method to precisely target a laryngeal nerve for treating sensory dysfunction.

## Contribution

A novel transnasal endoscopic approach with reduced variability for targeting the internal branch of the superior laryngeal nerve is validated.

## Key findings

- The mean distance from the ink mark to the iSLN confluence was 5.38 mm with low variability.
- The transnasal approach offers anatomically precise access to the iSLN compared to traditional methods.

## Abstract

This study aims to validate a novel transnasal endoscopic approach for accurately targeting the internal branch of the superior laryngeal nerve (iSLN) via the piriform sinus, with the goal of improving treatment outcomes for laryngeal sensory dysfunction (LSD).

Eight cadaveric larynges were examined using a 3D‐printed cadaveric laryngeal model. The superolateral quadrant of the piriform sinus was endoscopically marked with toluidine blue ink. The distance between the ink mark and the iSLN confluence point was measured as well as other landmarks.

The mean distance from the ink to the iSLN confluence was 5.38 mm, with significantly less variability than traditional external landmarks.

The transnasal approach provides a reliable, anatomically precise method for accessing the iSLN, offering potential advantages over traditional external techniques in the management of LSD.

This study validates a transnasal endoscopic approach to target the internal branch of the superior laryngeal nerve (iSLN) via the piriform sinus. Cadaveric analysis showed this method enables precise localization with minimal variability, offering a promising technique for treating laryngeal sensory dysfunction.