[Morphological changes of upper airway in patients with obstructive sleep apnea hypopnea syndrome after H-UPPP].

Objective

To investigate the morphological changes of the upper airway palatepharyngeal plane after modified uvulopalatopharyngoplasty（H-UPPP） in patients with obstructive sleep apnea hypopnea syndrome（OSAHS） and efficacy of the surgery.

Methods

Thirty-six patients diagnosed as moderate to severe OSAHS in the Central Hospital of Wuhan from January 2016 to September 2019 were treated with H-UPPP. PSG and 64 slice spiral CT were performed before operation, 1 month, 3 months, 6 months, 1 year and 2 years after operation to evaluate the changes of AHI, LSaO₂, CT90, BMI and the minimum anterior and posterior axis diameter, left and right axis diameter and cross-sectional volume of velopharyngeal plane, respectively.

Results

The AHI, LSaO₂, CT90, BMI were significantly improved, while the minimum anterior posterior axis diameter, left and right axis diameter and cross-sectional volume of velopharyngeal plane were enlarged in the maximum extent at one month after operation. The alteration of left and right axis diameter could be maintained until half a year after operation, but gradually retracted after 1 year after operation. The improvement of anterior and posterior axis diameter can only be maintained until 3 months after operation, and return to the preoperative level 2 years after operation; The minimum cross-sectional area improved significantly at 1 month after operation and decreased after 3 months, but there was still a significant improvement at 2 years after operation（P<0.05）. The change of AHI was similar to that of the minimum cross-sectional area, and there was still a significant difference at 2 years after operation（P<0.001）; The improvement of LSaO₂ was the most significant at 1 month after operation, which could be maintained until 3 months after operation, and then gradually recovered. The improvement of CT90 could be maintained until half a year after operation, and decreased significantly at 1 year after operation. BMI was still better than that before operation at 1 year after operation, but returned to the preoperative level at 2 years after operation. The improvement of AHI was mainly related to the minimum anterior posterior axis diameter and cross-sectional area of velopharyngeal plane, but not to the left and right axis diameters.

Conclusion

The morphological changes of upper airway in patients with OSAHS after H-UPPP are mainly the improvement of anterior posterior diameter, left and right diameter and minimum cross-sectional area caused by removing the anatomical load of upper airway within 3 months after operation, but the reduction of anterior posterior diameter and minimum cross-sectional area gradually occurs after 3 months, resulting in the weakening of surgical effect.