1
Introduction
According to a 2009 meta-analysis, 35% to 40% of children who undergo adenotonsillectomy (T&A) for obstructive sleep apnea (OSA) have persistent disease after surgery. Our discussion will briefly outline techniques currently used to identify sites of obstruction in these patients and will subsequently describe current medical and surgical management options for persistent OSA.
2
Identification of Sites of Obstruction
For children with persistent OSA, a thorough physical examination should be conducted. This should be aimed at identifying potential sites of obstruction ( Table 69.1 ) and additional factors that may be pertinent to the management of OSA. Body mass index (BMI) should be documented, as should syndromic features, neurologic status, and the presence of hypotonia. The modified Mallampati score should also be obtained.
| DISE | Cine MRI | Transnasal Flexible Laryngoscopy | |
|---|---|---|---|
| Requires sedation | X | X | |
| Allows identification of sleep-dependent conditions | X | X | |
| Assesses multiple upper airway sites simultaneously | X | ||
| Allows for easy visualization of laryngeal obstruction | X | X | |
| Allows for treatment at the time of evaluation | X | X (if done in the perioperative setting) | |
| Easy implementation | X | X |
Lateral cervical x-rays and flexible fiber-optic laryngoscopy can be used to assess possible regrowth of adenoidal tissue and to identify lingual tonsillar hypertrophy. In children with craniofacial disorders or retrognathia, skull x-rays or high-resolution computed tomography can be used to define the anatomy, thereby identifying specific areas of obstruction.
In light of the fact that airway reflexes and tone differ in the awake and asleep states, drug-induced sleep endoscopy (DISE) and cine magnetic resonance imaging (MRI) are increasingly being used in the overall assessment. These studies, as well as studies pertaining to additional methods of identifying sites of obstruction, are summarized in a 2016 systematic review by Manickam et al.
2.1
DISE
DISE is performed with the administration of an anesthetic that mimics natural sleep. A flexible endoscope is passed transnasally into the pharynx and larynx to evaluate possible sites of obstruction; this can be done immediately before sleep surgery. Although DISE and cine MRI effectively identify sites of obstruction in the oral cavity and oropharynx, DISE is better suited for the evaluation of nasal and laryngeal obstruction. Four studies of pediatric DISE have reported the effectiveness of this technique to identify at least one site of obstruction, and three of these studies have reported identification rates of 100%. The fourth study identified sites of obstruction in 100% of children with Down syndrome, but in only 52% of children without Down syndrome.
2.2
Cine MRI
Cine MRI yields detailed information on both anatomy and dynamic airway motion. Consecutive images of the upper airway are acquired over a 2-minute period. These high-resolution images are then displayed in a format that creates an active “movie” of airway motion and collapse during sleep. In contrast to DISE, this technique is able to simultaneously examine multiple levels of the airway, and is more likely to identify primary and secondary sites of obstruction. Additionally, due to the brightness of lymphoid tissue on T2-weighted images, adenoidal and lingual tonsillar hypertrophy are easily identified and quantified. Limitations of cine MRI include poor visualization of obstruction at the nose and larynx and the willingness of the anesthesiologist to assist with this technique.
3
Medical Therapies
3.1
Weight Loss
Literature regarding the impact of weight loss on OSA in children is sparse; however, a 2015 meta-analysis of adult studies reported that both surgical and nonsurgical weight loss were beneficial for reducing the BMI as well as the Apnea/Hypopnea Index (AHI); nonetheless greater benefit was derived from a surgical approach. Pediatric studies also suggest that weight loss can improve or resolve OSA in obese children. In 2012 the American Society for Metabolic and Bariatric Surgery recommended that bariatric surgery be considered for carefully selected, extremely obese adolescents who meet certain criteria. These criteria included children with a BMI ≥40 kg/m 2 who had an AHI ≥5 events/hour and those with a BMI ≥35 kg/m 2 who had an AHI ≥15 events/hour. A study of 10 children who underwent bariatric surgery reported significant improvements in both BMI and OSA severity after surgery; BMI decreased from a mean of 60.8 ± 11.07 to 41.6 ± 9.5 kg/m 2 , whereas AHI decreased from 9.1 to 0.6 events/hour.
3.2
Pharmacotherapy
Montelukast and intranasal corticosteroids are both used to treat mild to moderate pediatric OSA. A prospective, double-blind, randomized trial of 36 children evaluated AHI and adenoidal size before and after a 12-week treatment with daily oral montelukast. Authors reported that mean OSA severity decreased by 3.6 events/hour and that adenoidal hypertrophy also improved. In a follow-up retrospective cohort study of 752 children with mild OSA who were treated with both intranasal corticosteroids and oral montelukast for 12 weeks, an 81% success rate was reported. Polysomnography (PSG) was performed after therapy for 445 of these children; normalization of PSG parameters was seen in 62% of children, whereas 12% failed to show improvement and ultimately underwent T&A. Poor compliance with medication was seen in 8% of children. Treatment was less effective in obese children (BMI z-score >1.65) and children older than age 7.
3.3
Rapid Maxillary Expansion
Rapid maxillary expansion therapy is aimed at improving the nasal airway and widening the maxilla to improve airflow. Pirelli et al. published results of 31 children with isolated maxillary contraction and without adenoid hypertrophy or obesity who received this therapy and found that it resulted in an improvement in the mean AHI from 12.2 events/hour to 0.4 events/hour. This effect was sustained at 12 years for the 23 of 31 children who remained in the study. Children with maxillary contraction may be identified by a thorough oral cavity examination or when it is noted that the maxillary flanges of the Crowe–Davis retractor are too wide to properly seat on the patient’s upper dentition at the time of T&A.
3.4
Positive Airway Pressure and Oxygen
In a large series, continuous positive airway pressure (CPAP) therapy was shown to reduce the AHI and improve oxygen saturations in children; however, at least 30% of children stopped using CPAP within 6 months of initiation. CPAP compliance is noted to be particularly difficult for very young children or those with developmental delay. Oxygen administered via nasal cannula can often be tolerated better than CPAP and is therefore used to treat sleep apnea, but there is limited evidence to support its use.
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