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Original Article
Rapid maxillary expansion (RME) for pediatric obstructive sleep
apnea: a 12-year follow-up
Paola Pirelli a, Maurizio Saponara b, Christian Guilleminault c,*
aDepartment of Clinical Sciences and Translational Medicine, University of Tor Vergata, Rome, Italy
bDepartment of Otolaryngology and Neurology, La Sapienza University, Rome, Italy
cStanford University Sleep Disorders Clinic, Redwood City, CA, USA
ARTICLE INFO
Article history:
Received 22 February 2015
Received in revised form 14 April 2015
Accepted 16 April 2015
Available online 19 May 2015
Keywords:
Pediatric obstructive sleep apnea
Rapid maxillary expansion
Isolated maxillary deficiency
Very long-term follow-up
ABSTRACT
Objective: The objective of this study was to prospectively evaluate the long-term efficacy of rapid max-
illary expansion (RME) in a group of children with obstructive sleep apnea (OSA).
Material and method: Thirty-one children diagnosed with OSA were involved in the study. These chil-
dren had isolated maxillary narrowing and absence of enlarged adenotonsils at baseline. Twenty-three
individuals (73% of the initial group) were followed up annually over a mean of 12 years after the com-
pletion of orthodontic treatment at a mean age of 8.68 years. Eight children dropped out over time due
to either moving out of the area (n=6) or refusal to submit to regular follow-up (n=2). Subjects under-
went clinical reevaluation over time and repeat polysomnography (PSG) in the late teenage years or in
their early 20s. During the follow-up period, eight children dropped out and 23 individuals (including
10 girls) underwent a final clinical investigation with PSG (mean age of 20.9 years). The final evaluation
also included computerized tomographic (CT) imaging that was compared with pre- and post-initial treat-
ment findings.
Results: Yearly clinical evaluations, including orthodontic and otolaryngological examinations and ques-
tionnaire scores, were consistently normal over time, and PSG findings remained normal at the 12-year
follow-up period. The stability and maintenance of the expansion over time was demonstrated by the
maxillary base width and the distance of the pterygoid processes measured using CT imaging.
Conclusion: A subgroup of OSA children with isolated maxillary narrowing initially and followed up into
adulthood present stable, long-term results post RME treatment for pediatric OSA.
© 2015 Elsevier B.V. All rights reserved.
1. Introduction
Treatment of prepubertal children with obstructive sleep apnea
(OSA) is a difficult task. Since the 1970s, adenotonsillectomy (T&A)
has been considered the first-line treatment in non-syndromic chil-
dren. However, short- and long-term follow-up studies have shown
that many children have residual symptoms and elevated apnea–
hypopnea indexes (AHIs) after T&A. Several studies have also found
that OSA frequently recurs following T&A either alone [1–7] or in
combination with rapid maxillary expansion (RME) as initial treat-
ments [8–10]. Nasal continuous positive airway pressure (CPAP) is
a successful treatment for pediatric OSA, although compliance can
be problematic. This is particularly true for adolescents and young
adults. Additional data indicate that the CPAP mask necessary to ad-
minister positive pressure can have a detrimental effect on the
orofacial growth of a child over time, that is, worsening the anatomic
facial growth abnormalities, leading to increased collapsibility of
the upper airway during sleep [11]. We have prospectively fol-
lowed up children seen during prepubertal years for OSA who were
treated with RME. The initial data obtained on these children have
been previously reported [12]. Following initial posttreatment eval-
uation, these children were asked to undergo yearly orthodontic
evaluations, at which time information was collected on the de-
velopment of any new symptoms. This report presents the clinical
and polysomnographic (PSG) findings obtained during the prospec-
tive orthodontic follow-up. This study was approved by the University
of Tor Vergata institutional review board.
2. Materials and methods
2.1. Subjects
There were initially 31 Caucasian children (19 boys). The chil-
dren were seen at a mean age of 8.68 years (range: 6–12 years), and
all were considered as prepubertal based on clinical evaluation
(Tanner stage 1 [13]). They had a specific anatomic presentation:
none had enlarged T&A confirmed by a fiber-optic ear nose throat
* Corresponding author. Stanford University Sleep Medicine Division, 450 Broadway
Pavilion C 2nd Floor, Redwood City, CA 94063, USA. Tel.: +1 650 723 6601; fax: +1
650 721 6465.
E-mail address: cguil@stanford.edu (C. Guilleminault).
http://dx.doi.org/10.1016/j.sleep.2015.04.012
1389-9457/© 2015 Elsevier B.V. All rights reserved.
Sleep Medicine 16 (2015) 933–935
Contents lists available at ScienceDirect
Sleep Medicine
journal homepage: www.elsevier.com/locate/sleep
(ENT) evaluation, clear maxillary deficiency was present, and narrow
hard palates with unilateral or bilateral cross-bites were noted. The
studied children were distributed into three skeletal classes based
on the skeletal–sagittal relationship (class I, n=9; class II, n=14;
and class III, n=8). This distribution was expected, as maxillary con-
striction is an abnormality of the transverse diameter.
2.2. Follow-up evaluations
Following initial posttreatment evaluation, the children were
asked to undergo a yearly follow-up with an orthodontic special-
ist and an ENT specialist. Information was also collected from
questionnaires to evaluate for the development of any new pedi-
atric symptoms. Not all children came back for such an evaluation;
eight children dropped out of the follow-up group, including six who
moved out of the geographic area and two whose parents did not
want to return for a regular follow-up. The final group consisted of
23 individuals (73% of initial group).
The mean follow-up from the first evaluation to the last evalu-
ation of these 23 children was 12.3 ±1.5 years, and the mean time
from the initial posttreatment evaluation to the last evaluation was
12.0 ±0.5 years.
2.3. Testing
Evaluation consisted of clinical interview and evaluation, com-
pletion of the Pediatric Daytime Sleepiness Scale (PDSS) [14] or the
Epworth Sleepiness Scale (ESS) [15] based on the age of subject, and
the Italian translation of the Pediatric Sleep Questionnaire [16]. Each
child underwent annual otolaryngologic and orthodontic evalua-
tion until the final follow-up.
2.4. PSG evaluation
An ambulatory PSG was performed at entry and at final evalu-
ation. Electroencephalogram (EEG), eye movements, chin, leg
electromyogram (EMG), and respirations were monitored with a
nasal cannula, a mouth thermistor, an uncalibrated inductive ple-
thysmograph, thoracic and abdominal bands, a snore microphone,
a position sensor, and a finger pulse oximeter.
Computerized tomography (CT) imaging was performed at entry
and at final follow-up. Data were compared with initial pre- and
posttreatment findings.
2.5. Analysis
PSGs were scored (or rescored for initial studies) based on the
2007 American Academy of Sleep Medicine (AASM) recommenda-
tions [17]. Statistical analyses used paired t-test when data were
normally distributed and Wilcoxon signed-rank test otherwise; per-
centages were analyzed using chi-squared statistics, considering the
significant level at p=0.05. Calculations were performed using Sta-
tistical Package for Social Science (SPSS) version 17.
3. Results
Due to dropout during the follow-up period, the final group con-
sisted of 23 individuals (73% of initial group). As mentioned, the
mean follow-up from the first evaluation to the last evaluation was
12.3 ±1.5 years, and from the posttreatment evaluation to the last
evaluation 12.0 ±0.5 years. There were 13 boys with a mean age
(standard deviation, SD) of 20.9 ±1.2 years and 10 girls with a
mean age of 21.3 ±1.5 years at the time of final evaluation. None
of the subjects was overweight (mean body mass index,
BMI =22.7 ±1.3 kg/m2). All of them were at least Tanner stage 5
[13].
As initially reported at the end of the expansion at a mean age
of 8.57 years in the 23 followed-up children, there was an opening
of the inter-incisive space of 2.95 ±0.3 mm. PSG showed a change
in the mean AHI from 12.20 ±2.6 to 0.4 ±1.6 and oxygen satura-
tion nadir from 78.9 ±8.6% to 95.1 ±1.9%. Complete resolution of
clinical complaints had occurred [12].
Documents obtained at the yearly follow-up were reviewed: Clin-
ical evaluation and questionnaires indicated normal development
and absence of complaints or symptoms related to sleep-disordered
breathing. Over time, questionnaires always showed very low scores.
Regular orthodontics and ENT evaluations did not uncover any
abnormalities.
At the last evaluation, the 23 individuals with a continuous follow-
up had no indication of OSA recurrence: There was no clinical
complaint and no abnormal findings based on scales (with an ESS
mean score of 3 ±1). All individuals had normal schooling. The results
of the PSG are outlined in Table 1, and they are in a normal range
(see the insert in Table 1).
Statistical analyses comparing initial and final results showed
that there were no significant changes in PSG results between the
results obtained at the completion of initial treatment and at the
end of long-term follow-up (mean posttreatment follow-up =12 ±0.5
years).
CT imaging was obtained to analyze and compare the maxil-
lary base width and the distance of pterygoid processes at the initial
pretreatment and immediate posttreatment and at the end of long-
term follow-up. Analyses of these markers confirmed the stability
and maintenance of the anatomical changes induced by the orth-
odontic treatment.
4. Discussion
This is the longest follow-up investigation of children treated with
orthodontics presented to date, despite the fact that shorter pro-
spective follow-up and retrospective investigations have previously
been reported [9,10,18]. As expected, a small percentage of sub-
jects dropped out. However, 73% of the initial group remained until
the final follow-up, a percentage sufficient to bring valid informa-
tion. Our subjects had specific features that are not necessarily
present in all children with OSA who are treated with orthodon-
tics: There was no T&A enlargement at entry, and the orofacial
abnormalities were restricted to the maxilla. Finally, all children were
Caucasians from a very specific geographic area. These are not the
most common demographics when considering children with OSA.
However, the results indicate that a subgroup of children with the
anatomic characteristics described earlier have a strong possibili-
ty of achieving a sustained resolution of OSA following RME at a
prepubertal age.
One ENT study reported in the literature is related to ours. This
study investigated long-term outcomes post T&A in children with
sleep-disordered breathing [2]. In contrast to our study, these chil-
Table 1
Polysomnographic results immediately post treatment and at long-term (12 years)
follow-up.
Results after
completion of
initial RME (n =31)
Results at long
term follow-up
(n =23)
p-value
PSG parameters
AHI 0.4 ±1.1 0.3 ±0.9 NS
range 0–2.1 0–1.8 NS
Nadir SpO2 (%) 95.3 ±1.7 97. 2 ±1.5 NS
% sleep time with SpO2<92% 1.3 ±1.1 1.1 ±1.0 N S
Sleep efficiency (%) 89.2 ±7.7 90.1 ±6.5 NS
Legend: AHÍ: apnea-hypopnea-index % sleep time with SpO2<92%: percentage of
sleep-time spent below 92%.
934 P. Pirelli et al./Sleep Medicine 16 (2015) 933–935
dren were only treated by ENT approaches: Tasker et al. [2] evaluated
children who were initially scheduled to have T&A. The subjects were
surveyed, and they underwent home monitoring. Sixty-one chil-
dren were studied at baseline and assessed using questionnaires and
home ambulatory monitoring. EEG was not recorded, but pulse
transit time (PTT) and oximetry in association with recording of
snoring were the major variables. Pre- and post-treatment moni-
toring was compared with 30 age-matched control children without
clinical indication of enlarged adenotonsils. There was no yearly
follow-up, but 20 of the initial 61 subjects and 20 of the controls
(studied around four years) were reevaluated at around 16 years
of age. Fifteen of the ENT-treated children had T&A, three had ad-
enoidectomy alone, and two had tonsillectomy alone. The authors
reported that with their recording technique, the children who had
undergone T&A presented 12 years later with significantly more
snoring, and they showed significantly more respiratory efforts mea-
sured by PTT compared with controls. The authors attribute the
persistence of the differences between the two groups in part to
weight (obesity) and to nasal allergies. They also mentioned that
the prior T&A group retained “a narrower airway during sleep.”
Since 2002, investigations have shown the importance of de-
termining the impact of enlarged T&A on the growth of orofacial
structures in prepubertal children, as the orofacial structures may
not have developed in a normal fashion due to abnormal nasal
breathing [19,20]. Studies have also shown the importance of orth-
odontic treatment for upper airway narrowing in the presence of
sleep-disordered breathing, including post-T&A [8–10,18,21].
When comparing the literature data on the impact of both treat-
ments (orthodontics and T&A), one may question if orthodontic
treatment should not be the first approach when clinical evaluation and
testing indicate the presence of both problems. We already know that
in many cases, both treatments and retraining for nasal breathing during
sleep [8–10,21] will be needed to have stable, long-term gains. Our study,
however, shows that certain children with a specific anatomic presen-
tation and small tonsils and adenoids [21] maynotneedT&A,andthey
may experience a stable long-term gain when reaching adulthood.
A careful analysis of orofacial abnormalities, including en-
larged tonsils and/or adenoids, and maxillary–mandibular
involvement in the presence of sleep-disordered breathing is man-
datory to consider, as these elements may be associated with
incomplete results at the end of the treatment and/or with the re-
currence of OSA at a later age [8–10,21]. A subgroup of children with
a specific anatomic presentation at the time of initial diagnosis may
respond best to palatal distraction, despite the fact that in other cases
orthodontic treatment may only be a useful adjuvant to obtain long-
term normal breathing during sleep.
Conflict of interest
The ICMJE Uniform Disclosure Form for Potential Conflicts
of Interest associated with this article can be viewed by clicking
on the following link: http://dx.doi.org/10.1016/j.sleep.2015
.04.012.
Acknowledgment
We thank Jennifer Liebenthal, MD, for her help in editing this
manuscript.
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