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

OBJECTIVES: To evaluate the efficacy of simple tonsillectomy to treat obstructive sleep apnoea syndrome (OSAS) in adults. DESIGN: Prospective study. SETTING: Tertiary referral centre. PARTICIPANTS: 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. MAIN OUTCOME MEASURES: 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. RESULTS: 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). CONCLUSIONS: 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.