Improvement in obstructive sleep apnea in a child with Down syndrome with rapid palatal expansion

Abstract

Children with Down syndrome (DS) have distinct orofacial structures that predispose them to sleep-disordered breathing. The management options for obstructive sleep apnea include continuous positive airway pressure, adenotonsillectomy, mandibular advancement, and maxillary expansion. However, most of these treatment options are less effective or less viable for children with DS. Rapid maxillary expansion with a fixed orthodontic appliance is a viable alternative for DS patients because it separates the midpalatal suture and dilates the airway, regardless of the patient’s compliance. We present a case of a 15-year-old boy with DS and severe obstructive sleep apnea, which dramatically improved with rapid maxillary expansion and subsequent orthodontic treatment. Although only the short-term changes have been presented in this report, this case emphasizes the need for further discussions on the viability of rapid maxillary expansion for treating obstructive sleep apnea in children with DS.

Citation:

Kim A, Cho HJ, Choi EK, Choi YJ. Improvement in obstructive sleep apnea in a child with Down syndrome with rapid palatal expansion. J Clin Sleep Med. 2022;18(7):1885–1888.

INTRODUCTION

First reported in 1866, Down syndrome (DS) is a hereditary disease, characterized by a trisomy of chromosome 21. The distinct orofacial structure of DS, including midfacial and maxillary hypoplasia (narrow and high palatal vault), macroglossia, and small pharynx, as well as other characteristics, such as muscle hypotonia and overweight, increase the risk of obstructive sleep apnea (OSA).¹ The prevalence of OSA in children with DS varies from 69 to 90%, which is higher than that in normal children.² Sleep-disordered breathing causes behavioral and cognitive problems and worsens the cardiovascular disease symptoms associated with DS.³ Therefore, treatment of sleep-disordered breathing improves the neurocognitive function and quality of life of patients with DS. Although attention to the sleep problems related to patients with DS has increased, treatment guidelines for patients with DS and OSA have not been established. In fact, most treatment options for OSA are not practical, particularly for children with DS, because of their compliance problem. We speculated that airway dilatation and sleep apnea control using rapid palatal expansion (RPE) may be beneficial for the treatment of OSA, particularly in patients with DS. Here we present a case involving a child with DS and severe OSA that significantly improved with RPE therapy. The patient’s parents provided informed consent for publishing this report.

REPORT OF CASE

A 15-year-old boy presented with orofacial features characteristic of DS, including midfacial hypoplasia, prognathic facial profile, low nasal bridge, narrow, high, and deep palate, and macroglossia. He had been diagnosed with DS at birth and severe OSA at the age of 14 years. The lateral cephalometric examination revealed a low-positioned tongue and hyoid bone and a constricted airway. His parents were concerned about his poor quality of sleep because of mouth opening throughout the sleep duration, snoring, an unusual sleep posture (prone position with his face forward and his chin on the pillow), tossing, and turning. Polysomnography revealed a total obstructive apnea-hypopnea index (total apnea index + total hypopnea index including hypopneas with arousals and hypopneas with ≥ 3% desaturation) of 46.2 events/h, sleep efficiency of 62.1%, an arousal index of 40.9, moderate snoring, and a lowest oxygen desaturation of 86.9%.

The management options for OSA include continuous positive airway pressure (CPAP) titration, adenotonsillectomy, mandible advancement, and maxillary expansion. Although CPAP is a noninvasive and effective treatment method, it was not considered for this patient due to concerns regarding his compliance. Adenotonsillectomy was not indicated since there was no noted tonsillar hypertrophy. Mandibular advancement was not applicable because of existing mandibular prognathism. Therefore, maxillary expansion was selected, because widening of the maxillary bone would result in upper airway dilatation, resulting in OSA improvement. In addition, maxillary arch expansion would address his sleep problem as well as his orthodontic issues, specifically the transverse discrepancy, teeth crowding, and posterior crossbite.

Since the patient was a growing child, a nonsurgical RPE was planned using an expansion screw appliance.⁴ The expander appliance, consisting of an expansion screw in the middle, was bound on the maxillary teeth. The parents were asked to turn the screw once a day (0.2 mm per 1 turn) with a unique key. The expansion was performed for 28 days, and separation of the midpalatal suture was confirmed on the periapical radiograph (Figure 1A).

Figure 1. Improvement in obstructive sleep apnea after rapid palatal expansion.

(A) Periapical radiographs show separation of the midpalatal suture. (B) Intraoral photographs show increase in the intercanine and intermolar widths and correction of posterior crossbite. (C) Serial lateral cephalograms show increase in the pharyngeal airway with elevation of the tongue and hyoid bone. (D) Posterior-anterior cephalograms show increase in the nasal cavity width, maxillary width, and intermolar width. The arrows indicate separation of the midpalatal suture. A = point A, AW = airway width, B = point B, HH = hyoid height, MP = mandibular plane, N = nasion, PP = palatal plane, S = sella, TH = tongue height.

After maxillary expansion, the patient showed dramatic improvement, although light snoring persisted. His parents were satisfied that their son could sleep in a normal posture, which was supine, lateral, or prone. The orthodontic changes were evaluated through the model and radiographic analysis. The maxillary arch expanded and transformed from a V-shape to a U-shape after treatment. The movement of the upper molars addressed the occlusion issues and allowed backward movement of the mandible, thus improving his prognathic profile. Upon comparing the radiographs, the low-positioned tongue and hyoid bone were also found to be elevated, and the hypopharyngeal airways were dilated (Figure 1B). The most notable change was found in polysomnography, which was performed 1 year after the maxillary expansion. The report revealed significant improvements in his obstructive apnea-hypopnea index, sleep efficiency, and arousal index, and he was subsequently diagnosed with mild OSA (Table 1). Table 1 and Figure 1 detail the changes before and after treatment.

Table 1.

Improvement in obstructive sleep apnea after rapid palatal expansion.

	Before Treatment	After Rapid Palatal Expansion
Polysomnography
OAHI	46.2	14.2
Sleep efficiency (%)	62.1	79.3
Arousal index	40.9	18.5
Nadir SpO2 (%)	86.9	85.8
Sleep architecture	Increased stage N1 sleep (38.8%) Decreased stage N2 sleep (29.7%) Increased stage N3 sleep (25.0%) Decreased REM sleep (6.5%)	Increased stage N1 sleep (16.0%) Normal stage N2 sleep (64.2%) Normal stage N3 sleep (13.1%) Decreased REM sleep (6.7%)
Model analysis
Intercanine width (mm)	29.9	35.9
Intermolar width (mm)	40.9	45.2
Palatal height (mm)	22.5	19.2
Palatal volume (mm3)	7,457.8	8,597.6
Lateral cephalometric analysis
ANB (°)	0.9	2.2
SN-MP (°)	26.7	27.3
Tongue height (mm)	17.7	15.1
Hyoid height (mm)	80.0	76.1
Airway width (mm)	7.2	12.3
P-A cephalometric analysis
U6 cusp-U6 cusp (mm)	50.9	57.8
Maxillary width (mm)	56.6	57.7
Nasal base width (mm)	23.3	24.7

Tongue height was measured by taking the perpendicular distance of the dorsum of tongue to the nasal floor; maxillary width pertains to the distance between right and left jugale; the nasal base width was the widest distance between right and left nasal cavity. ANB = point A-nasion-point B angle, which indicates the skeletal relationship between the maxilla and mandible, OAHI = obstructive apnea-hypopnea index, P-A = postero-anterior, REM = rapid eye movement, SpO₂ = saturation of peripheral oxygen, SN-MP = angle between sella-nasion plane and mandibular plane, which indicates vertical facial pattern, U6 = maxillary first molar.

The patient’s parents provided informed consent for publishing this report.

DISCUSSION

Children with DS are predisposed to OSA compared with children without DS. The patient in our case had the typical orofacial features of DS and severe OSA. After the maxilla and nasal airway had been expanded through RPE, he was subsequently diagnosed with mild OSA.

RPE causes the separation of the midpalatal suture, thus causing expansion of the nasal floor and airway and increasing the oral cavity volume.^4–7 Therefore, RPE addresses sleep-related breathing disorders and dental problems, such as the transverse discrepancy between the maxilla and mandible, crowding, and posterior crossbite. The amount and duration of the expansion should be determined according to the occlusion in each patient, with subsequent orthodontic treatment to manage the changes in occlusion. Moreover, nonseparation of the midpalatal suture causes side effects, including teeth flaring and alveolar bone dehiscence, which warrant close monitoring.

Patients with OSA and DS rarely have good compliance to the conventional treatment modalities. The American Academy of Pediatrics recommends adenotonsillectomy as the first line of treatment for adenotonsillar hypertrophy, followed by CPAP,⁸ although the treatment must be customized for individual cases. However, adenotonsillectomy is reportedly less effective for children with DS than for those without.¹ Furthermore, OSA was found to persist in 73% with DS who underwent adenotonsillectomy.⁹ Mandibular advancement device can aggravate the malocclusion and disrupt the facial profile of growing children with DS, who typically present with class III malocclusion due to maxillary underdevelopment. CPAP is not preferred due to compliance issues.

Although RPE resulted in significant changes, we have only described its short-term effects in this case report. RPE can be a viable option for patients with DS and OSA because it also addresses the oropharyngeal and orthodontic issues while demanding minimal compliance from the patient, unlike CPAP. Although the therapeutic effects and stability of RPE on OSA in children without DS have been reported,⁵ few studies have discussed the impact of RPE on OSA in children with DS. Children with DS are 3.09 times more likely to have a narrow maxilla and posterior crossbite than are children without DS.¹⁰ Therefore, RPE can be a viable treatment option for both OSA and malocclusion in patients with DS, primarily because it is effective in resolving orthodontic problems without the need for patient compliance. As sleep problems can affect the general growth, cognitive function, and intellectual development of children, RPE needs further discussion as a treatment strategy for patients with OSA and DS.

DISCLOSURE STATEMENT

All authors have seen and approved this manuscript. This work was funded by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. NRF-2020R1F1A1069316). The authors report no conflicts of interest.

ABBREVIATIONS

CPAP

continuous positive airway pressure

DS

Down syndrome

OSA

obstructive sleep apnea

RPE

rapid palatal expansion