Description of the condition
Sleep-disordered breathing (SDB) is a spectrum of disease that affects both children and adults and ranges in severity from primary snoring to obstructive sleep apnoea syndrome (OSAS). Primary snoring, the mildest expression of SDB, is not associated with arousal from sleep or episodes characterised by below normal levels of oxygen saturation in arterial blood. In contrast, OSAS, the most severe expression of SDB, involves repeated episodes of restricted breathing (hypopnoea) or complete obstruction (apnoea), or both, with reduction in the normal levels of oxygen saturation in arterial blood and arousal during sleep (Nespoli 2013).
SDB is a common condition in the paediatric population, with an estimated prevalence of primary snoring and OSAS in children ranging from 8% to 27% and 1% to 5%, respectively (Marcus 2012; Shine 2005). Obesity is a well-established risk factor for SDB (Shelton 1993; Shine 2005). Since childhood obesity rates are rising in many Western countries, the prevalence of SDB is expected to increase in the coming years.
In children, hypertrophy of the tonsils and adenoid tissue is thought to be the most important cause of SDB; it causes narrowing of the airway, which is a particular problem during sleep when the muscles of the pharynx relax, leading to partial or complete obstruction of the airway (Marcus 2005).
An overnight sleep study (polysomnography) is considered the most comprehensive investigation for diagnosing OSAS (Marcus 2012). In many countries, however, this test is not routinely performed in children with a suspected diagnosis of OSAS because of its high cost, labour-intensive nature and limited availability (Marcus 2012). Therefore, in everyday practice the severity of SDB is usually assessed with a clinical history and examination, with or without overnight pulse oximetry (Brietzke 2004).
SDB has a considerable impact on children's quality of life, comparable to that of juvenile rheumatoid arthritis (Baldassari 2008), and has been linked with behavioural and neurocognitive morbidities (Beebe 2006; Owens 2009; Tauman 2011). Cognitive assessments show that children with SDB score six points lower on average compared to those without SDB on the Wechsler Preschool and Primary Scale Intelligence IQ test (Gottlieb 2004). This difference persists when only children with symptoms of SDB, rather than polysomnogram-diagnosed OSAS, are analysed. Children with SDB have also been shown to be more likely to suffer from behavioural problems, such as hyperactivity, emotional lability and aggression, than children without SDB (Rosen 2004). Furthermore, children with untreated OSAS, the most severe form of SDB, are at risk of severe health problems, including failure to thrive and cardiovascular diseases such as hypertension, cor pulmonale and left ventricular hypertrophy (Marcus 2001).
Description of the intervention
Surgical removal of the tonsils with or without removal of the adenoids, called (adeno)tonsillectomy, is a common surgical procedure in children (Erickson 2009). In tonsillectomy the palatine tonsils are removed from their investing tissue in the oropharynx; it can be performed by blunt dissection, guillotine, bipolar electrocautery, laser, microdebrider or coblation according to the surgeon's preference. Adenoidectomy involves the removal of the adenoid (pharyngeal tonsil) from the nasopharynx; common techniques include curettage or suction cautery. The operation involves a general anaesthetic and can be performed as a day case or with an overnight stay (Cooper 2013; Lalakea 1999; Marcus 2012). Certain children undergoing surgery for SDB are at increased risk of peri- and postoperative respiratory compromise (Baugh 2011; Lipton 2003; Robb 2009; Schwengel 2009). Guidelines from the American Academy of Pediatrics (Marcus 2012) and the UK Royal College of Paediatrics and Child Health (Royal College of Paediatrics and Child Health 2009) recommend overnight observation for high-risk cases, such as young children (below four years of age), those with certain comorbidities (cardiac and/or craniofacial abnormalities, neuromuscular disorders) or in children with severe OSAS (e.g. an oxygen saturation level in arterial blood of 80% or lower or an Apnoea/Hypopnoea Index (AHI) greater than 24).
Throat pain and reduced oral intake are common following (adeno)tonsillectomy, with over 50% of children still experiencing pain three days after the operation despite analgesia. Vomiting and nausea occur less frequently, with one in 10 children reporting vomiting several days postoperatively (Stanko 2013). The most common complication is postoperative bleeding, which may occur in up to 5% of children (Baugh 2011). Over the past decade there has been increasing interest in partial removal of the tonsils, known as tonsillotomy, which may be associated with lower postoperative morbidity and fewer complications than complete removal of the tonsils (tonsillectomy). Several randomised controlled trials (RCTs) have compared tonsillectomy and tonsillotomy for SDB in children (Walton 2012), but this comparison will be addressed in a separate Cochrane review.
We will include all types of non-surgical management of SDB that are commonly used in daily clinical practice.
Lifestyle interventions: dietary advice, exercise programmes.
Medical management: intranasal and oral corticosteroids, leukotriene receptor antagonists.
Mechanical interventions: continuous positive airway pressure (CPAP).
Watchful waiting: observation and monitoring.
Recent evidence has suggested that children with OSAS have raised local and systemic inflammatory markers, which causes proliferation of lymphoid tissue within the tonsils and adenoids (Kim 2009). Intranasal and systemic corticosteroids aim to increase airway patency by reducing the inflammatory response occurring in the oropharynx. Leukotriene levels have also been shown to be higher in the adenotonsillar tissue of children with OSAS compared to those with tonsillitis (Goldbart 2004). This is why the use of leukotriene receptor antagonists such as montelukast has been suggested to have beneficial effects in children with SDB (Friedman 2011). Other non-surgical management options for SDB involve non-invasive ventilatory support (e.g. CPAP) and reducing the effort of breathing with weight loss regimes.
How the intervention might work
In children, hypertrophy of the tonsils and adenoid tissue is thought to be the most important cause of SDB. Therefore, removal of the adenoid and tonsils, i.e. adenotonsillectomy, is widely considered an effective treatment for SDB in children. Non-randomised and uncontrolled studies have shown improvements in objective and subjective measures of sleep, behaviour, cognition and quality of life (Garetz 2008). A 2009 systematic review, however, showed that (adeno)tonsillectomy may not be curative, with only two out of three children achieving complete polysomnographic resolution (Friedman 2009).
Why it is important to do this review
There is convincing evidence of an association between childhood SDB and adverse health outcomes. Consequently, the identification and implementation of an effective treatment for this common condition in children should prevent those outcomes and improve health. With (adeno)tonsillectomy offering significant improvements in sleep as measured by subjective measures (e.g. parental reporting) and objective measures such as polysomnography, the operation is nowadays considered a valuable first-line treatment for SDB in children. However, the potential benefits of (adeno)tonsillectomy in children, a surgical procedure performed under a general anaesthetic, should be carefully balanced against the risks, including the risk of adverse events. We aim to systematically review the clinical effectiveness and safety of (adeno)tonsillectomy compared to non-surgical management for SDB in children.