Laryngoscopy findings and histological results in a rabbit gastroesophageal reflux model.

The role of lower esophageal sphincter (LES) in laryngopharyngeal reflux is controversial. In this study, we used an animal model to investigate the association between LES dysfunction and reflux laryngitis. Twelve healthy New Zealand albino rabbits (2.5-3.5 kg) were utilized in this study. The animals were divided into two groups. Eight rabbits underwent total cardiomyectomy to induce reflux, and the remaining four rabbits underwent a control sham operation. A laryngoscopy and a 24-hour intra-esophageal pH-metry were performed prior to surgery and again 2 and 8 weeks postsurgery. After the final laryngoscopy, all animals were sacrificed to obtain histological results. Total cardiomyectomy significantly increased the reflux index, the duration of the longest reflux episode and the total number of episodes that occurred in 24 h postsurgery. No significant difference was observed in the reflux finding score (RFS) between preoperative and 2-week postoperative rabbits (P = 0.11). But there was a statistically significant change in the RFS before and 8 weeks after the induction of reflux from 4.6 ± 0.9 to 8.3 ± 3.6 (P = 0.02). Submucous gland hyperplasia and inflammation were significantly increased in the reflux group compared to the control group. The results of this study suggest that chronic lower esophageal sphincter dysfunction is associated with reflux laryngitis in rabbits.