# Analysis on the plane and mechanism of tongue-originated obstruction in Obstructive Sleep Apnea Syndrome (OSAS) patients with macroglossia

## TL;DR

This study identifies the velopharyngeal plane as the main obstruction site in OSAS patients with macroglossia and suggests surgical focus on the middle tongue.

## Contribution

The study identifies the velopharyngeal plane as the primary obstruction site and proposes a surgical approach targeting the middle tongue in OSAS with macroglossia.

## Key findings

- The velopharyngeal plane is the most common obstruction site in OSAS patients with macroglossia.
- The middle part of the tongue is suggested as the optimal surgical site for treating OSAS with macroglossia.
- Soft palate thickness and retrolingual space showed no significant differences between OSAS patients and controls.

## Abstract

•The velopharyngeal plane was the most common site to develop obstruction.•Compared with the normal, retrolingual space was increased in the OSAS patients.•The dorsal tongue in contact with the soft palate during supine sleep for everyone.•Analysis of the mechanisms of tongue- originated obstruction in OSAS patients.•The choice of the surgical site is in the middle part of the tongue for OSAS.

The velopharyngeal plane was the most common site to develop obstruction.

Compared with the normal, retrolingual space was increased in the OSAS patients.

The dorsal tongue in contact with the soft palate during supine sleep for everyone.

Analysis of the mechanisms of tongue- originated obstruction in OSAS patients.

The choice of the surgical site is in the middle part of the tongue for OSAS.

To investigate the plane and related mechanisms of tongue-originated obstruction in Obstructive Sleep Apnea Syndrome (OSAS) patients with macroglossia, utilizing pharyngeal Magnetic Resonance Imaging (MRI) in combination with Upper Airway Pressure Monitoring (UAPM).

Nineteen OSAS patients with macroglossia and 19 healthy controls were enrolled in this study. Every case was examined by pharyngeal MRI and Polysomnogram (PSG). The minimum Retropalatal Space (RP), the minimum Retrolingual Space (RL), soft palate thickness and the minimum space from the dorsal tongue to the soft palate (TP) were measured on a midsagittal plane. UAPM was measured only in the OSAS group. The differences of results between groups were statistically analyzed.

Both UAPM and pharyngeal MRI indicated that the obstruction plane was present in patients with OSAS along the velopharyngeal plane. The mean values of both RP and RP/RL of patients with OSAS in this study were significantly smaller than control group values (p < 0.05). There was no significant difference in RL and soft palate thickness across the two groups (p > 0.05). The value of TP in both groups was close to 0, showing no significant difference between groups (p > 0.05).

The velopharyngeal plane was the most common site demonstrating obstructive etiology in OSAS patients with macroglossia. The related mechanism is suspected to include the backward movement of the soft palate caused by the high arch and the fall of the middle segment of the hypertrophic tongue. These findings may inform tongue-related surgical site decision-making for OSAS patients with macroglossia.

IV: Retrospective cohort study.