Postdeglutitive residue in vagus nerve paralysis and its association with feeding style.

The objective of this study is to compare the postdeglutitive pharyngeal residues between Xth cranial nerve paralysis (XNP) and isolated recurrent laryngeal nerve paralysis (RLNP) to elucidate the association with feeding style. This study enrolled 15 XNP patients with injuries at the brainstem level (Group I) and 26 patients with RLNP (Group II). All subjects underwent videofluoroscopic swallowing studies (VFSS). The pyriform sinus (PS) and vallecula residues were quantified. The symmetry of the affected versus non-affected sides was compared in both groups. Feeding style at the time of VFSS was also examined. The intra-rater correlation coefficients for all of the data, including the areas of both the vallecula and pyriform sinus on the affected and non-affected sides, were 0.88-0.92 (p < 0.001), reflecting high consistency of the evaluation. In Group I, there was significantly (p < 0.01) more residue in the PS, but not vallecula, compared to the respective non-affected sides, while in Group II there were no significant differences in residue between the affected and non-affected sides for either the vallecula or PS. Comparing Groups I and II, there was significant (p < 0.01) residue on the affected side in the PS but not the vallecula. There was a significant correlation between dependency on a feeding tube and XNP (p < 0.01, Chi-square test). XNP at the brainstem level may cause significantly increased residue in the PS compared to RLNP. This might increase the dependency on a feeding tube with XNP.