Level 3

For patients with Apert and Crouzon syndrome, occipital cranial expansion with distraction (conventional distraction or with springs) may result in a greater increase in head circumference (an approximate measure of intracranial volume), intracranial volume and a significantly lower prevalence of tonsillar herniation (3/11 versus 7/8) and papilledema (4/19 versus 11/18) compared to a fronto-orbital advancement or an occipital expansion without distraction after more than 5 years of follow-up. B Spruijt et al, 2016; C De Jong et al, 2013; Thomas et al, 2014; Derderian et al, 2015; Mundinger et al, 2016