The foramen magnum in isolated and syndromic brachycephaly

Childs Nerv Syst. 2014 Jan;30(1):165-72. doi: 10.1007/s00381-013-2245-y. Epub 2013 Oct 18.

Abstract

Background: Though the foramen magnum (FM) is often altered in complex craniosynostosis, no study analysed the FM dimensions in patients with brachycephaly specifically.

Patients and methods: We measured the FM area, sagittal and transverse diameters on preoperative CT scans in patients with bicoronal synostosis (n = 40) and age-matched control group (n = 18). Our study included 16 children with FGFR3 p.Pro250Arg mutation (mean age 6.1 months), 10 with TWIST-1 mutation (mean age7.6 months) and 14 patients with isolated bicoronal synostosis (mean age 6.1).

Results: We observed a significantly smaller FM area in FGFR3 group compared to control group and isolated brachycephaly group (p = 0.001 and p = 0.038, respectively). The mean FM area in FGFR3 group was 426.13 mm(2) (p = 0.001), while in TWIST-1 group was 476.34 mm(2) (p = 0.103), and in isolated brachycephaly group 489.43 mm(2) (p = 0.129) compared to control group: 528.90 mm(2). The posterior segment of the sagittal diameter of the FM and its width as well as the bi-interoccipital synchondrosis diameters were significantly smaller in FGFR3 group compared to control group. In TWIST-1 group, the only altered dimension was the FM anterior segment of the sagittal diameter (p = 0.008). We did not observe any significant alteration of FM in patients with isolated brachycephaly compared to control group.

Discussion and conclusions: The FM area is significantly altered in FGFR3-related brachycephaly, whereas in patients with Saethre-Chotzen syndrome (TWIST-1 mutation) the mean FM area is similar to control group. This study confirms the importance of FGFRs on FM growth whereas TWIST-1 seems to have a minor role.

MeSH terms

  • Craniosynostoses / diagnostic imaging*
  • Craniosynostoses / surgery*
  • Female
  • Foramen Magnum / diagnostic imaging*
  • Foramen Magnum / surgery*
  • Humans
  • Imaging, Three-Dimensional / methods
  • Infant
  • Infant, Newborn
  • Male
  • Syndrome
  • Tomography, X-Ray Computed / methods