Correlation between polysomnographic and endoscopic investigation data in patients with sleep-disordered breathing associated with post thyroidectomy recurrent nerve palsy

BACKGROUND. Sleep respiratory pathology is closely related to physiological and pathophysiological characteristics of respiratory control during sleep. Due to the anatomical disposition of the muscles, changes in their tonicity may lead to upper airways obstruction during sleep. The upper airway of the patients with obstructive sleep apnea syndrome and vocal cord paresis of different aetiologies can significantly narrow during inspiration. The objective of the present study was to evaluate the influence of the laryngeal pathology, such as unilateral or bilateral recurrent nerve palsy, on the degree of sleep apnea. MATERIAL AND METHODS. A retrospective clinical study was conducted (2010-2011) on a total of 30 patients with postthyroidectomy unilateral or bilateral recurrent nerve palsy. The examination protocol included: flexible nasopharyngoscopy performed during sleep for evaluating the nasopharyngeal, retrovelar, oropharyngeal and hypopharyngeal region, followed by rigid laryngeal endoscopy and stroboscopy. Polysomnography was used as a method of identifying the patients with sleep respiratory disorders. RESULTS. Out of the 30 patients, 28 were women (93.33%) and 2 men (6.67%) (mean age = 48 ± 1.4). The unilateral recurrent nerve palsy was the most frequently encountered - 70% of the patients. 3.33% had bilateral recurrent nerve palsy with vocal cords in lateral position, 20% had paramedian recurrent palsy, and 6.67% had bilateral recurrent nerve palsy with vocal cords in median position. Statistical data revealed significant differences between the apnea-hypopnea index (AHI) values, for different types of vocal cord paralysis. CONCLUSION. Our statistical evaluation has shown that AHI increases in patients with bilateral recurrent nerve paralysis, compared to those with unilateral paralysis. Establishing curative medical, surgical, as well as foniatric or continuous positive airway pressure treatment, we can improve AHI value, sleep quality and patient’s quality of life.