The Extracellular Matrix of the Lateral Pharyngeal Wall in Obstructive Sleep Apnea

Study Objectives: To compare the components of the extracellular matrix in the lateral pharyngeal muscular wall in patients with and without obstructive sleep apnea (OSA). This may help to explain the origin of the increased collapsibility of the pharynx in patients with OSA. Design: Specimens from the superior pharyngeal constrictor muscle, obtained during pharyngeal surgeries, were evaluated using histochemical and immunohistochemical analyses to determine the fractional area of collagen types I and II, elastic fibers, versican, fibronectin, and matrix metalloproteinases 1 and 2 in the endomysium. Setting: Academic tertiary center. Patiens: A total of 51 nonobese adult patients, divided into 38 patients with OSA and 13 nonsnoring control subjects without OSA. Interventions: Postintervention study performed on tissues from patients after elective surgery. Measurements and Results: Pharyngeal muscles of patients with OSA had significantly more collagen type I than pharyngeal muscles in control subjects. Collagen type I was correlated positively and independently with age. The other tested components of the extracellular matrix did not differ significantly between groups. In a logistic regression, an additive effect of both the increase of collagen type I and the increase in age with the presence of OSA was observed (odds ratio (OR), 2.06; 95% confidence interval (CI), 1.17-3.63), when compared with the effect of increased age alone (OR, 1.11; 95% CI, 1.03-1.20). Conclusion: Collagen type I in the superior pharyngeal constrictor muscle was more prevalent in patients with OSA and also increased with age. It was hypothesized that this increase could delay contractile-relaxant responses in the superior pharyngeal constrictor muscle at the expiratory-inspiratory phase transition, thus increasing pharyngeal collapsibility.

Influence of adenotonsillectomy on hard palate dimensions

Objective: To evaluate hard palate width and height in mouth-breathing children pre- and post-adenotonsillectomy. Methods: We evaluated 44 children in the 3-6 year age bracket, using dental study casts in order to determine palatal height, intercanine width, and intermolar width. The children were divided into two groups: nasal breathing (n = 15) and mouth breathing (n = 29). The children in the latter group underwent adenotonsillectomy. The study casts were obtained prior to adenotonsillectomy, designated time point 1(11), at 13 months after adenotonsillectomy (T2), and at 28 months after adenotonsillectomy (13). Similar periods of observation were obtained for nasal breathing children. Results: At T1, there was a significantly lower intercanine width in mouth breathing children; intermolar width and palate height were similar between groups. After surgery, there was a significant increase in all the analyzed parameters in both groups, probably due to facial growth. Instead, the increase in intercanine width was substantially more prominent in mouth breathing children than in nasal breathing children, and the former difference failed in significance after the procedure. Conclusions: There were no significant differences between the nasal-breathing and mouth-breathing children in terms of intermolar width and palatal height prior to or after tonsillectomy. Although intercanine width was initially narrower in the mouth-breathing children, it showed normalization after the surgical procedure. These results confirm that the restoration of nasal breathing is central to proper occlusal development. (C) 2012 Elsevier Ireland Ltd. All rights reserved.