However, the procedure’s limited rate of success requires additional therapies post-surgery, the investigators said.
The study, “Adenotonsillectomy for the Treatment of Obstructive Sleep Apnea in Children with Prader-Willi Syndrome: A Meta-analysis,” was published in the journal Otolaryngology–Head and Neck Surgery.
People with PWS experience sleep problems that include daytime sleepiness and obstructive sleep apnea, a condition characterized by repetitive episodes of momentary stops in breathing during sleep. OSA is the most common type of sleep apnea and is highly prevalent in children with PWS. A previous study showed that OSA affects a much higher percentage — nearly 80% — of children with Prader-Willi than children without this disorder (up to 4%).
OSA is linked with an increased risk of cardiovascular and cognitive problems. As such, early diagnosis and proper management of this condition in children with PWS are key, the researchers said.
The main cause of pediatric OSA is the enlargement of the tonsils and adenoids. Adenotonsillectomy, a procedure that removes both types of glands, is the first-line treatment for such cases. Yet, the outcomes of adenotonsillectomy in PWS children with obstructive sleep apnea remain unclear.
To investigate whether such surgeries improve sleep in PWS children, researchers at the National Taiwan University performed a meta-analysis — a statistical assessment combining the results of several studies.
From 139 studies retrieved from four databases up to February 2019, the team analyzed six. These studies involved a total of 41 children with PWS, mean age 5 years, who underwent adenotonsillectomy to treat OSA. The studies were conducted in Italy and the U.S. All children were assessed before and after surgery with polysomnography — a test to diagnose sleep disorders, which records brain waves, blood level of oxygen, heart rate, breathing, and leg movements.
Specifically, the scientists assessed changes in oxygen levels and in the apnea–hypopnea index (AHI), which measures sleep apnea severity. This score is calculated by dividing the number of events — apneas and hypopneas, or shallow breathing — by the number of hours of sleep. An AHI score lower than 5 indicates normal sleep, while 5 to 30 means mild-to-moderate sleep apnea, and a score greater than 30 reveals severe sleep apnea.
Surgical success was defined using two thresholds: an AHI lower than 5, or lower than 1.
The results showed that the average AHI score was 13.1 before surgery and decreased to an average of 4.6 after the procedure. After surgery, 21% of the patients reached an AHI lower than 1, while 71% achieved an AHI lower than 5.
This shows that the surgery’s overall success rate is “far below 100%,” the researchers said. Therefore, “additional treatment for residual OSA should be considered postoperatively in children with PWS,” they said.
Only one study reported oxygen levels in the blood, with no significant differences before and after surgery.
Traditionally, the most frequent complications of adenotonsillectomy include respiratory symptoms and hemorrhage. But two of the analyzed studies also reported post-surgery velopharyngeal dysfunction, which occurs when air leaks to the nasal passages during speech production. This condition requires another surgical intervention and careful management, the investigators said.