Preliminary evaluation of treatment of obstructive sleep apnea and hypopnea syndrome using modified Herbst appliance

PURPOSES: To evaluate the effectiveness of modified Herbst oral appliance in treatment of obstructive sleep apnea and hypopnea syndrome(OSAHS) by three-dimensional CT.METHODS: Ten patients with mild or moderate OSAHS by PSG were included in the study.The upper airway was scanned at normal respiration and Muller's maneuver by spiral CT(GE lightspeed ultra).Each patient was treated using Herbst oral appliance and adjusted several times until the subjective symptoms were improved.Three month later,each patient was re-evaluated by PSG and re-scanned by three-dimensional CT in two positions.The cross-section area with its corresponding sagittal and transverse diameters and the volume at retropalatal and retroglossal regions,the site and range of upper airway structure was evaluated.Paired t test was used for data analysis using SPSS 12.0 software package.RESULTS: There were significant differences between pre-treatment and three months after treatment with Herbst appliance subjectively and objectively.The transverse diameter and cross-section area were increased significantly at retro palatal and retro lingual level(P0.05).The volume of upper airway was augmented significantly(P0.05).Muller's test before and after treatment indicated that obstructive sites were decreased obviously.CONCLUSIONS: Modified Herbst appliance is effective for mild or moderate OSAHS.The upper airway three-dimensional CT with Muller's maneuver can be used in evaluating upper airway and the efficiency of treatment with oral appliance.