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

OBJECTIVE

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).

METHODS

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.

RESULTS

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).

CONCLUSIONS

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.

LEVEL OF EVIDENCE: IV: Retrospective cohort study.