Surgical treatment of obstructive sleep apnea : randomized controlled studies in children and adults

Sammanfattning: Obstructive sleep apnea (OSA) is a common disorder in both children and adults. In adults, OSA is a major health concern because it is highly prevalent and increases the risk for hypertension, cardiovascular disease, and mortality. The primary treatment for adults is continuous positive airway pressure (CPAP), but surgery with uvulopalatopharyngoplasty (UPPP) is an alternative in selected cases. Although CPAP has been shown to successfully improve a patient’s respiratory sleep parameters, this treatment only modestly improves their blood pressure. The treatment effect of UPPP in improving blood pressure has been less understood, and this effect was evaluated in Paper I. Surgery is the primary treatment for children with OSA, and adenotonsillectomy (ATE), the removal of the tonsils and adenoid, is the first choice of treatment. While ATE is effective in improving quality of life and respiratory sleep parameters, residual OSA after surgery is not uncommon, especially in children with obesity or severe OSA. A modified ATE with closure of the tonsillar pillars, called adenopharyngoplasty (APP), has been suggested to improve the surgical outcome. This surgical method was evaluated in Papers II and III. Although OSA occurs frequently in children that are between two and four years of age, there are no randomized controlled trials (RCT) evaluating the efficacy of surgery in this population of children; therefore, this was studied in Paper IV. Randomized controlled trials are the optimal study design to evaluate cause-effect relationships between different treatments and outcomes, but there are few RCTs evaluating surgical treatment of OSA. This thesis aims to use RCTs to evaluate surgical treatment of OSA in children and adults. Paper I evaluated changes in morning blood pressure from an RCT that compared patients who received modified UPPP (n = 32) with a control group (n = 33). The control group also received surgery six months after their first follow-up. The results showed that UPPP improved both systolic and diastolic blood pressure after six months. The results in all operated patients also indicated that there still was an improvement in both systolic and diastolic blood pressure after 24 months. Papers II and III reported on an RCT in children, two to four years of age, with severe OSA. The patients were randomly assigned to APP (n = 36) or ATE (n = 47) and had a follow-up after six months. Respiratory sleep parameters, which were measured with polysomnography (PSG), and quality of life, which was measured with a questionnaire called OSA-18, were evaluated in Paper II. This study did not show that APP was more effective than ATE. Postoperative morbidity, such as pain, infection, bleeding, satisfaction with treatment, swallowing, and speech, was assessed by a logbook, questionnaire, and medical records. The results, presented in Paper III, showed only small differences between the groups, in favor of ATE. The combined results of these studies suggest that ATE should still be considered as the primary treatment for otherwise healthy children with severe OSA. Paper IV reported on an RCT in children, two to four years of age, with mild to moderate OSA. The patients were randomly assigned to ATE (n = 29) or watchful waiting (n = 31) and were evaluated with PSG and the OSA-18 questionnaire after six months. The results showed only small differences regarding respiratory sleep parameters, but children with moderate OSA showed greater improvement after ATE. There were also large differences in quality of life between the groups, which increased more after ATE. These results suggest that children with moderate OSA should be considered for early ATE, whereas children with low OSA-18 scores and mild OSA might benefit from a period of watchful waiting.