The precise role of maxillary constriction in the pathophysiology of obstru
ctive sleep apnea (OSA) is unclear. However, it is known that subjects with
maxillary construction have increased nasal resistance and resultant mouth
-breathing, features typically seen in OSA patients. Maxillary constriction
is also associated with alterations in tongue posture which could result i
n retroglossal airway narrowing, another feature of OSA. Rapid maxillary ex
pansion (RME) is an orthodontic treatment for maxillary constriction which
increases the width of the maxilla and reduces nasal resistance. The aim of
this pilot study was to investigate the effect of rapid maxillary expansio
n in OSA. We studied 10 young adults (8 male, 2 female, mean age 27+/-2 [se
m] years) with mild to moderate OSA(apnea/hypopnea index-AHI 19+/-4 and min
imum SaO(2) 89+/-1%), and evidence of maxillary constriction on orthodontic
evaluation. Ail patients underwent treatment with RME, six cases requiring
elective surgical assistance. Polysomnography was repealed at the completi
on of treatment. Nine of the 10 patients reported improvements in snoring a
nd hypersomnolence. There was a significant reduction in AHI (19+/-4 vs 7+/
-4, p<0.05) in the entire group. In seven patients, the AHI returned to nor
mal (ie, =<5); only one patient showed no improvement. These preliminary da
ta suggest that RME may be a useful treatment alternative for selected pati
ents with OSA.