Early Tonsillectomy for Mild Obstructive Sleep Apnea: Too Early to Draw Conclusions

Approximately 500 000 US children undergo tonsillectomy, with or without adenoidectomy, every year.^1–2  Most adenotonsillectomies are performed for obstructive sleep-disordered breathing (OSDB), which encompasses a broad range of conditions from primary snoring to obstructive sleep apnea.^3,4  OSDB is prevalent in children and more common in children who are overweight, Black, Hispanic, or economically disadvantaged.^5–8  Children with OSDB experience neurobehavioral issues, including problems with attention, hyperactivity, and learning. These sequelae may be explained by disruptions in sleep and intermittent hypoxia. However, social and environmental factors also play a role as root causes of both OSDB and neurobehavioral concerns.^9–11  Because of the high prevalence of OSDB in children, especially in vulnerable populations, and its impact on behavior and learning issues, for which vulnerable children are more at risk, optimizing appropriate, timely treatment of OSDB is a public health priority.

In this issue of Pediatrics, Waters et al¹²  report on the cognitive, behavioral, and sleep effects of adenotonsillectomy in preschool-aged children 24 months after being randomly assigned to the Preschool Obstructive Sleep Apnea Tonsillectomy Adenoidectomy (POSTA) trial, which compared the effects of early surgery to surgery performed after 12 months.¹²  The primary outcome in the trial was global cognitive ability, as measured by the Brief Intellectual Ability (BIA) score of the Woodcock-Johnson III Test of Cognitive Abilities. The BIA combines comprehension-knowledge (verbal ability), fluid reasoning (thinking ability), and processing speed (efficiency in performing cognitive tasks) into a single measure of global cognitive ability that can be reliably assessed in children as young as 2 years of age.¹³  In the investigators’ previous report describing the POSTA trial’s findings at 12 months, just before the children assigned to delayed adenotonsillectomy underwent surgery, no difference was found in BIA scores between groups. However, children who had early surgery had greater improvements in polysomnography indices, parent-reported sleep symptoms, behavior, and overall health.¹⁴  In the current study, the investigators report similar long-term (24-month) improvements in intelligence (BIA scores), polysomnography indices, parent-reported sleep symptoms, global indices of behavior, and overall health between groups. The single reported outcome that was superior at 24 months for the early surgery group was the parent-reported score on the Behavior Assessment Scale for Children somatization subscale, which assesses physical symptoms, such as pain, weakness, and other bodily complaints.

These findings warrant discussion for several reasons. First, the POSTA trial is the first randomized controlled trial to assess the effects of adenotonsillectomy for OSDB >1 year after intervention. Second, the trial was focused on preschool-aged children, who comprise the majority of US children undergoing adenotonsillectomy for OSDB. Third, few other prospective comparative studies to date have evaluated the impact of adenotonsillectomy on cognitive and behavioral function in children, and none have been focused on preschool-aged children.^15–17  The only previous randomized trial evaluating this question, the Childhood Adenotonsillectomy Trial, included children aged 5–9 years with mild-to-moderate obstructive sleep apnea and revealed that, at 7 months, parent-reported behavior was more improved among children who had been assigned to undergo adenotonsillectomy versus watchful waiting. Test scores on measures of attention and executive function were similarly improved in both groups, although specific measures of nonverbal reasoning and fine motor skills improved more in the surgery group.^15,18 

Taken together, the findings of these trials suggest beneficial effects of adenotonsillectomy, regardless of timing, on sleep and behavior but not global cognitive ability. Greater reductions in somatic symptoms in the early surgery group in the POSTA trial raise the possibility of some long-term benefit of early versus delayed surgery. However, the absence of differences on other sleep-related and behavior measures at 24 months indicate similar positive effects in children who underwent delayed surgery. Furthermore, although positive effects of both early and delayed surgery on select aspects of cognition are reported, these improvements are difficult to interpret in light of expected age-related changes over time, the use of age-unadjusted scores from cognitive testing, and the possibility of changes in parent ratings and test scores across repeated assessments.^19,20  A further limitation of the POSTA trial is the high attrition (∼30% loss to follow-up at 24 months), which led to reduced statistical power for outcome comparisons and possibly selection bias. Also, because the control group in the trial underwent surgery at 12 months, the study cannot elucidate the long-term effects of adenotonsillectomy versus watchful waiting without surgery in preschool-aged children with OSDB.

In light of these findings and limitations, although early surgery may provide some benefit, it seems that watchful waiting is a reasonable strategy for some preschool-aged children with mild OSDB to allow for the monitoring of natural age-related neurobehavioral improvements.

BIA

Brief Intellectual Ability

OSDB

obstructive sleep-disordered breathing

POSTA

Preschool Obstructive Sleep Apnea Tonsillectomy Adenoidectomy