Effect of UPPP with respect to site of pharyngeal obstruction in sleep apnoea: follow-up at 18 months by overnight recording of airway pressure and flow.

Continuous recording of upper airway pressure and airflow can identify the sites of obstructive events during sleep, and their relative distribution along the upper airway segments. A separation of transpalatal and subpalatal obstructive events has been used. The purpose of the present study was to investigate if uvulopalatopharyngoplasty (UPPP) had reduced transpalatal more than subpalatal obstructive events 18 months postoperatively, and to investigate any influence of age and obesity. Fourteen consecutive male patients were investigated by overnight recording of upper airway pressure and airflow before, and 18 months after, UPPP. The localization of obstructive events pre- and postoperatively revealed that the proportion of obstructive events located transpalatally were reduced from 65.1 to 30.5% of all (P < 0.05). Viewing the two sites separately, the reduction in number of transpalatal events (81%) was higher than the reduction in subpalatal events (42%) (P < 0.05). Age + Body Mass Index (BMI) correlated inversely with relative reduction in subpalatal events but did not correlate to any change in transpalatal events. Treatment response with regards to reduction in recorded Apnoea Hypopnoea Index (AHI) was achieved in 9 out of the 11 patients who had mainly transpalatal obstructive events preoperatively.