Foramen magnum stenosis, cervicomedullary decompression, and growth in children with achondroplasia: a retrospective cohort study

BACKGROUND: Foramen magnum stenosis (FMS) is a serious complication in children with achondroplasia that may necessitate cervicomedullary decompression (CMD). It is unclear how FMS and CMD influence growth in these children. This study aimed to assess the effects of FMS and CMD on the growth of children with achondroplasia. METHODS: Eighty-seven children (45 males, 42 females) with achondroplasia, aged 4 to 6 years, were evaluated. Height, weight, head circumference, and body mass index were expressed as standard deviation scores (SDS) according to Merker et al., while sitting height SDS was derived using Tanner’s methods. FMS was graded on magnetic resonance imaging using Fornarino’s score. RESULTS: Fifty-two patients (26 males, 26 females) underwent CMD at a median age of 0.95 years (IQR 0.52;1.50). Of these, 28 (53.8%) were under one year old at the time of CMD, with a median age of 0.6 years (0.4;0.7). The remaining 24 children had CMD after their first year of life, with a median age of 1.6 years (1.3;2.8). The median age at anthropometric assessment was 5.16 years (4.74;5.50). Children who underwent CMD showed significantly lower median height SDS, particularly among males compared to females (p=0.026). CONCLUSIONS: Impaired growth in children with foramen magnum stenosis requiring cervicomedullary decompression may primarily reflect greater disease severity, while the potential contribution of surgery remains uncertain.