Tonsil size and body mass index are important factors for efficacy of simple tonsillectomy in obstructive sleep apnoea syndrome

Abstract

To evaluate the efficacy of simple tonsillectomy to treat obstructive sleep apnoea syndrome (OSAS) in adults. Prospective study. Tertiary referral centre. Thirty patients (28 males) underwent simple tonsillectomy under general anaesthesia. The patients' mean age was 33.2 +/- 6.8 years and body mass index was 30.7 +/- 6.0 kg/m2. Seven patients (23%) were classified with grade 4, 16 patients (53%) with grade 3, and seven patients (23%) with grade 2 according to the tonsil size of Friedman's classification. The number of apnoea episodes per hour (apnoea index), the number of apnoea and hypopnoea episodes per hour (apnoea-hypopnoea index), lowest nocturnal oxygen saturation and oxygen desaturation time were measured during overnight polysomnography before and after surgery. A successful tonsillectomy was defined as an apnoea-hypopnoea index improvement ratio of > or =50% and an apnoea-hypopnoea index <20 after operation. Apnoea-hypopnoea index decreased from 69.0 +/- 28.4/h to 30.1 +/- 24.0/h (P < 0.0001). Simple tonsillectomy was successful in all six patients with body mass index <25 kg/m2. Concerning success rate of simple tonsillectomy with tonsil, size 2 was lowest (42.9%). Eight of the 13 patients who used continuous positive airway pressure before simple tonsillectomy did not use continuous positive airway pressure after simple tonsillectomy because of a significant reduction of excessive daytime sleepiness. Continuous positive airway pressure decreased significantly after simple tonsillectomy from 13.6 +/- 2.5 cmH2O preoperatively to 10.6 +/- 1.3 cmH2O postoperatively (P < 0.05). These data suggest that simple tonsillectomy is a beneficial modality to treat OSAS in selected patients (larger tonsil, low body mass index), even in adults.