[Effects of uvulopalatopharyngoplasty on patients with obstructive sleep apnea--the severity of preoperative tonsillar hypertrophy].

Predicting outcome following uvulopalatopharyngoplasty (UPPP) in obstructive sleep apnea is difficult. We hypothesized that UPPP is effective in obstructive sleep apnea patients with severe tonsillar hypertrophy. We examined the relationship between the severity of pre-operative tonsillar hypertrophy and the effect of UPPP in 38 patients with obstructive sleep apnea (oxygen desaturation index (ODI) > or = 20). The patients were classified into three groups according to the Mackenzie Classification of tonsillar hypertrophy. Ten patients were classified as grade 1 (M1) hypertrophy, i.e. tonsils just visible beyond the palatal arch. Five patients had grade 3 (M3) hypertrophy, i.e. tonsils appearing to contact each other at the midline. The remaining 23 patients had grade 2 (M2) hypertrophy, i.e. intermediate enlargement. We measured the apnea index, ODI, DST 90, and DST 85 (%time with SaO2 < or = 90% and < or = 85%, respectively) using a screening device for sleep apnea (Apnomonitor II, CHEST M. I. Co. Tokyo, Japan) before and after UPPP. Following UPPP, the mean ODI decreased significantly in all groups: 59 to 9/hr (p < 0.005) in the M3 group, 53 to 27/hr (p < 0.001) in the M2 group, and 48 to 33/hr (p < 0.05) in the M1 group. Post-UPPP ODI decreased by 83% in M3, 45% in M2, and 28% in M1 patients. Successful UPPP, defined by a post-UPPP ODI of less than 20/hr and a greater than 50% decrease in post-UPPP ODI, occurred in 80% of M3, 43% of M2, and 10% of M1 patients. We conclude that tonsillar hypertrophy can predict a successful response to UPPP in obstructive sleep apnea patients.