Changes of the retrolingual pharynx during the Muller manoeuvre and during sleep in sleep apnoea.

OBJECTIVE: To determine whether the retrolingual pharynx shows the same morphometric modifications during the Muller manoeuvre and during drug-induced sleep endoscopy (DISE) with propofol in patients submitted for maxillomandibular advancement surgery. SUBJECTS AND METHODS: Eighteen patients submitted for maxillomandibular advancement surgery (MMAS) were evaluated endoscopically before and 6 month after surgery in the region of the retrolingual pharynx while seated and lying in dorsal decubitus (supine) while performing the Muller manoeuvre and during DISE with propofol, to verify and measure if the same morphometric changes occur in the retrolingual pharynx during the Muller manoeuvre and during DISE with propofol. The area, anteroposterior, and laterolateral retrolingual pharynx images were acquired using the Sony Vegas 8.0 software and recorded on a DVD. The Image J software was used to measure and compare these images. RESULTS: An increase in the pharyngeal aperture was observed in all measurements after surgery, specifically in area retrolingual pharynx images. When the Muller manoeuvre was performed, a greater gain (113%) in area retrolingual pharynx measurement was observed when the patient was awake and seated. With the patient was in dorsal decubitus during DISE with propofol there was a greater gain in area retrolingual pharynx measurement (201.33%) in the smaller aperture. CONCLUSION: The Muller manoeuvre after MMAS does not simulate the dimensions of the pharynx that occur during sleep.

Volumetric analysis of the pharynx in patients with obstructive sleep apnea (OSA) treated with maxillomandibular advancement (MMA).

INTRODUCTION: Maxillomandibular advancement (MMA) has been reported to be the most effective surgical treatment of obstructive sleep apnea (OSA). Most reports about MMA aim to confirm the efficiency of this treatment modality, but few describe the anatomical changes produced in the pharynx by the surgery. Thus, the objective of the present investigation was to quantify the anatomical changes of the pharynx that occur in patients with OSA after MMA surgery using magnetic resonance (MR). METHODS: Twenty patients with a polysomnographic diagnosis of OSA participated in the study. All patients were submitted to image acquisition by MR performed during wakefulness. Polysomnography and MR were performed preoperatively and 6 months after MMA. Volume analysis (in cubic millimeters) was performed as the sum of the areas multiplied by their thickness, with no intervals between sections. The pharyngeal air space of the region between the hard palate and the base of the epiglottis was divided into a retropalatal (RP) region and a retrolingual (RL) region. RESULTS: Postoperative MR showed a mean volumetric increase of 26.72 % in the RP region and of 27.2 % in the RL region. DISCUSSION: MMA increases the air space of the pharynx by expanding the facial skeletal structure to which the soft tissues of the pharynx and tongue are fixed, with a consequent reduction of collapsibility in the presence of negative pressure during inspiration. This reduced possibility of pharyngeal collapse may contribute to the reduction of obstructive events.

Morphometric endoscopic study of the pharynx in patients with sleep apnea.

PURPOSE: The aims of the study were to measure endoscopically the retrolingual pharynx during wakefulness and sleep before and after maxillomandibular advancement surgery and to quantify the changes observed. MATERIALS AND METHODS: Eighteen patients with mild to severe grade obstructive sleep apnea hypopnea were evaluated during wakefulness while sitting and lying down and during induced sleep in dorsal decubitus while breathing naturally. Images of the retrolingual region of the pharynx were captured with a nasofibroscope and recorded on a DVD using the Sony Vegas 8.0 software (Sony Creative Software, Madison, WI). The images captured in greater and smaller aperture were measured with the Image J software (produced by Wayne Rasband, United States National Institutes of Health, Bethesda, MD) in linear anteroposterior and linear laterolateral areas. A correction factor was then applied to equalize the size of the images and thus compare them to one another. RESULTS: The postoperative dimensions of the pharynx always increased significantly in all measurements compared with the preoperative ones. During induced sleep in dorsal decubitus, there was a greater gain in the area of smaller aperture (201.33%). CONCLUSIONS: The proposed method showed that the dimensions of the pharynx always increased significantly after surgery for maxillomandibular advancement, although the gain was not homogeneous in all dimensions and also varied according to state of consciousness. The greatest gain was observed in the area of smaller aperture with the patient in induced sleep, thus reducing the collapse of the pharynx.