Children diagnosed with syndromic craniosynostosis often experience pronounced sleep breathing disorders because of midface hypoplasia. This condition can have varying degrees of impact on the overall development and quality of life of the affected children. Le Fort III osteotomy and midface advancement has been shown to be effective in correcting obstructive sleep disorders and improving facial appearance (Cohen MM Jr, 1993). Moreover, in cases where conservative treatments such as positive pressure ventilation and/or adenoid/tonsil removal are insufficient, midface advancement can be considered even in patients aged <6 years (Guilleminault et al., 1978; Marcus and Loughlin, 1996). However, previous studies have not extensively documented the correlations among respiratory function, upper airway expansion, and the extent of midface advancement. Therefore, the objective of the present study was to analyze these correlations by measuring the morphological changes in the upper airway and sleep breathing indices following surgical intervention.