Radiographic and histologic characterization of tongue base tissues obtained by transoral robotic surgery in patients with obstructive sleep apnea

Objective: Our aim was to radiographically and histologically characterize the tongue base tissues removed after robotic surgery and to analyze their relationship with polysomnographic measurements in obstructive sleep apnea. Methods: Medical records, radiographs and histologic specimen of the patients who underwent transoral robotic tongue base reduction surgery were retrospectively reviewed. Findings in computed tomography (CT) images, histopathological features of the removed tongue base tissues, and respiratory parameters in polysomnography were compared and analyzed. Results: Surgical specimens and CT images were available from 13 patients (aged 29–61 years). Histologic examination showed that the removed tissues comprised four layers—epithelial, lymphoid follicular, glandular, and muscle tissue. The median (interquartile range) thickness of the epithelial, lymphoid, and glandular layers was 0.29 (0.24–0.44) mm, 3.37 (1.67–4.75) mm, and 3.75 (3.45–4.10) mm, respectively. The lymphoid layer thickness on CT was correlated with that in the histologic section (r = 0.967, p < 0.001). However, the thickness of each layer had no significant correlation with the polysomnographic parameters. Conclusion: The tongue base tissue removed by transoral robotic surgery in OSA patients comprised four distinctive layers including epithelial, lymphoid follicular, glandular and muscular layers. These layered structures could also be discriminated in the CT images.