Improved Visualization of the Internal Branch of the Superior Laryngeal Nerve during Pharyngeal Endoscopic Subepithelial Dissection with Use of Red Dichromatic Imaging

ABSTRACT Endoscopic subepithelial dissection is a minimally invasive treatment for superficial pharyngeal neoplastic lesions, requiring preservation of important neural structures such as the internal branch of the superior laryngeal nerve (ibSLN). We report a case in which red dichromatic imaging (RDI) appeared to improve the visualization of a linear structure presumed to be the ibSLN compared with white‐light imaging (WLI). A 57‐year‐old woman underwent endoscopic subepithelial dissection for a 5‐mm superficial lesion on the pharyngoepiglottic fold. Both WLI and RDI revealed a whitish linear structure beneath the lesion, which was presumed to represent the ibSLN based on its anatomical location and course. The presumed nerve structure appeared to be more clearly delineated with RDI than with WLI before mucosal incision and remained identifiable after submucosal injection and during dissection. This enhanced visualization may have helped guide the selection of the mucosal incision line and dissection plane. En bloc resection was achieved without apparent nerve injury. No dysphagia, hoarseness, or other adverse events occurred postoperatively. These findings suggest that RDI may serve as a useful adjunct for visualization of the structure presumed to represent the ibSLN during pharyngeal endoscopic subepithelial dissection and may support nerve‐preserving strategies.