An Assisted Diagnostic Technique To Locate Obstruction And Assess Efficacy Of Upper Airway Surgery In Patients With Obstructive Sleep Apnea-Hypopnea Syndrome

Objective:This study aims to investigate and determine the feasibility of nasopharyngeal tube or NT-aided positioning diagnosis of upper airway obstruction, and its application value in surgical efficacy assessment.Methods:A total of 27 cases with medium or severe Obstructive Sleep Apnea-Hypopnea Syndrome (OSAHS) had been selected, and controlled trials were carried out, with Apnea Graph (AG) and NPT-AG tests before the modified uvulopalatopharyngoplasty(UPPP) surgery combined with tongue base RFA to relieve upper airway obstruction. Polysomnography (PSG) was used to determine effectiveness of surgery after six months, and correlation analysis between AG, NPT-AG results on the base-of-tongue plane and surgery efficacy was performed as well.Results:Three cases out of 27 (11.1%) lost to follow-up after surgery were excluded, two cases out of 27 (7.4%) failed to undertake the AG test, and four out of 25 (16%) failed to complete the NPT-AG test. A total 18 valid cases out of 27 were included. Two sets of measurements of hypopnea index, mixed apnea index, obstructive apnea index, average arterial oxygen saturation of blood, apnea hypopnea index (AHI) were obtained via AG and NPT-AG tests respectively, and with significant differences between each other (p<0.05).NPT-AG measurements of hypopnea index and average oxygen saturation were higher than those measured by AG, and AG results of mixed apnea index, obstruction index and AHI were higher than those observed by NPT-AG.NPT-AG reported incidence of mean upper number (MUN) trended towards zero, and the incidence of undefined mean number(UMN) was also reduced remarkably. The correlation of the average AG-tested incidence of lower plane obstrrction with the difference between pre-surgery AG-reported AHI and post-surgery AHI tested by PSG was analyzed (r1=0.445, P>0.05).Whereas, the average incidence of mean lower number observed via NPT-AG was in highly positive correlation with the variance between pre-surgery AG-reported AHI and post-surgery PSG-reported AHI (r2=0.606**, P<0.01).Conclusion:NPT-AG test is capable of ruling out the disturbance caused by the soft palate plane, and targeting only obstructive condition of the tongue base plane. The efficacy of tongue base MLN increases along with increased incidence of tongue base plane obstruction. And this assisted diagnostic technique is a beneficiary complement to the normal AG test.