Computer-assisted quantitative evaluation of obstructive sleep apnea using digitalized endoscopic imaging with Muller maneuver

OBJECTIVE: To validate the technique of the Muller maneuver (MM) using videoendoscopy and to quantify the correlation between its clinical results and variables of polysomnography. STUDY DESIGN: Prospective, controlled study. METHODS: Videoendoscopy with MM was performed in 70 patients who were categorized into two groups, with 35 patients giving a history suggestive of snoring and 35 patients without such history. The snoring group underwent further examination with polysomnography. Cross-sectional areas at the retropalatal (RP) and retrolingual (RL) levels during quiet respiration (RP0 or RL0) and the maximal effort of MM (RP1 or RL1) were calculated with the digital measurement software "Image J." One hundred forty pairs of data were acquired. The collapsing ratio (CR) was defined as the difference of RP0 (or RL0) between RP1 (or RL1) divided by RP0 (or RL0) to compare the difference between the two phases. These results were compared with each other and correlated to the variables obtained from polysomnographic studies. RESULTS: There were significant differences in the CR of RP (CRRP), the CR of RL (CRRL), and body mass index (BMI) when comparing the two groups. In snoring patients, BMI was positively related to the respiratory disturbance index (RDI) and obstructive sleep apnea (OSA) staging but not to CRRP and CRRL. CRRP had a significant positive relationship with RDI and OSA rather than CRRL. CONCLUSION: MM with videoendoscopy can be a simple, cost-effective, quantitative, and even predictable technique. This method allows us to examine the dynamic upper airway for more precise preoperative planning.