The Laryngoscope
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The pathophysiologic events that lead to the loss of airway compensation in obstructive sleep apnea (OSA) are poorly understood. The development of airway instability may be secondary to changes in neurologic control, airway morphology, or both. To identify potential histopathologic features of pharyngeal tissues that may contribute to OSA, transverse sections of the distal soft palate and uvula were qualitatively compared using light and electron microscopy from 4 severe apneics (greater than 50 apnea/hour), 4 severe snorers (less than 20 apnea/hour), and 4 nonsnorers. ⋯ Electron microscopy of severe apneics identified frequent focal degeneration of myelinated nerve fibers and axons. The finding of similar histopathologic changes in apneics and severe snorers supports previous speculation of a common etiology not directly related to apnea, such as vibratory trauma to pharyngeal tissues. Degenerative changes in peripheral nerves, identified on electron microscopy, however, may contribute to airway instability and the development of obstructive apnea by impairing pharyngeal reflexes.