PERSISTENCE OF OBSTRUCTIVE SLEEP APNEA SYNDROME IN CHILDREN AFTER ADENOTONSILLECTOMY RIVA TAUMAN, MD, TANYA E. GULLIVER, MD, JYOTI KRISHNA, MD, HAWLEY E. MONTGOMERY-DOWNS,PHD, LOUISE M. O’BRIEN,PHD, ANNA IVANENKO, MD, PHD, AND DAVID GOZAL, MD Objective To investigate the relative contribution of various risk factors to the surgical outcome of adenotonsillectomy for obstructive sleep apnea syndrome in children. Study design Children (n  110; mean age, 6.4  3.9 years) underwent two polysomnographic evaluations before and after adenotonsillectomy. In addition, 22 control children were studied. History for allergy and family history of sleep-disordered breathing was taken before each polysomnographic evaluation. Results Significant changes in sleep stage percentages and sleep fragmentation were found in the postsurgery study compared with the presurgery study; 25% of the children had apnea/hypopnea index (AHI) <1, 46% had AHI >1 and <5, and 29% had AHI >5 in the postsurgery study. The frequency of subjects with AHI <1 after surgery was significantly lower among obese subjects (P < .05). Comparison between the children who had AHI <1 after surgery and 22 control children showed complete normalization of sleep architecture after surgery. Conclusions Adenotonsillectomy yields improvements in respiratory abnormalities in children with obstructive sleep apnea syndrome. Complete normalization occurs in only 25% of the patients. Obesity and AHI at diagnosis are the major determinant for surgical outcome. When normalization of respiratory measures occurs after surgery, normalization of sleep architecture will also ensue. (J Pediatr 2006;149:803-8) O bstructive sleep apnea syndrome (OSAS) is a common condition in children 1 and is associated with potentially long-lasting cardiovascular, 2,3 neurobehavioral, 4,5 and somatic growth consequences. 6 Since the most common cause of OSAS in children is adenotonsillar hypertrophy, it is widely accepted that the first line of treatment is adenoton- sillectomy. However, the effectiveness of adenotonsillectomy and the major determinants of postsurgical outcome have not been critically delineated. Previous reports have shown a significant reduction in respiratory abnormalities and arousal index after surgery. 7-14 However, persistence of abnormal polysomnographic findings after surgery is reported in approximately 20% to 40% of cases. 9-14 The severity of OSAS is a potentially important consideration that can affect the impact of adeno- tonsillectomy. 8 Other factors previously suggested to affect surgical outcome included orthodontic and craniofacial factors, 11,12,15,16 ethnicity, positive family history of sleep- disordered breathing (SDB), 17,18 and young age. 13 One of the most important potential contributors to residual airway obstruction after surgery is obesity. However, the effect of obesity on the outcome of adenotonsillectomy in children has been examined in only a few studies with either small sample sizes or no polysomnographic data. 9,17,19,20 We investi- gated the relative contribution of multiple potential risk factors such as disease severity, obesity, age, family history of SDB, ethnicity, and allergy on the surgical outcome of adenotonsillectomy for OSAS in a large cohort of children. METHODS Two standard nocturnal polysomnographic evaluations were performed in 110 children, before and after adenotonsillectomy at the Kosair Children’s Hospital, Louisville, Kentucky. AHI Apnea/hypopnea index relBMI Relative body mass index OSAS Obstructive sleep apnea syndrome REM Rapid eye movement SDB Sleep-disordered breathing SWS Slow-wave sleep TST Total sleep time From the Kosair Children’s Hospital Re- search Institute and the Department of Pe- diatrics, Division of Pediatric Sleep Medi- cine, University of Louisville, Louisville, Kentucky. This study was supported by the National Institutes of Health (grant HL-65270), The Children’s Foundation Endowment for Sleep Research, and the Commonwealth of Kentucky Challenge for Excellence Trust Fund. RT was supported by an Ohio Valley American Heart Association Fellowship. Submitted for publication Jan 23, 2006; last revision received Jul 17, 2006; accepted Aug 25, 2006. Reprint requests: David Gozal, MD, Kosair Children’s Hospital Research Institute, Uni- versity of Louisville School of Medicine, 571 S. Preston Street, Suite 204, Louisville, KY 40202. E-mail: david.gozal@louisville.edu. 0022-3476/$ - see front matter Copyright © 2006 Mosby Inc. All rights reserved. 10.1016/j.jpeds.2006.08.067 803