G Coll1, F Abed Rabbo2, V Jecko3, L Sakka4, F Di Rocco5, M Delion6. 1. Service de neurochirurgie, CHU de Clermont-Ferrand, 63000 Clermont-Ferrand, France; CNRS, SIGMA Clermont, institut Pascal, université Clermont Auvergne, 63000 Clermont-Ferrand, France. Electronic address: gcoll@chu-clermontferrand.fr. 2. Service de neurochirurgie, CHU de Clermont-Ferrand, 63000 Clermont-Ferrand, France. 3. Service de neurochirurgie, CHU de Bordeaux, Bordeaux, France. 4. Service de neurochirurgie, CHU de Clermont-Ferrand, 63000 Clermont-Ferrand, France; Laboratoire d'anatomie et d'organogenèse, laboratoire de biophysique sensorielle, NeuroDol, faculté de médecine, université Clermont Auvergne, 63000 Clermont-Ferrand, France. 5. Service de neurochirurgie pédiatrique, hôpital femme-mère-enfant, 33 000 Lyon, France; Inserm 1033, université Claude-Bernard, 69008 Lyon, France. 6. Service de neurochirurgie, CHU d'Anger, 49100 Anger, France.
Abstract
BACKGROUND: The growth of the posterior fossa in syndromic craniostenosis was studied in many papers. However, few studies described the pathophysiological growth mechanisms in non-operated infants with fibroblast growth factor receptor (FGFR) type 2 mutation (Crouzon, Apert or Pfeiffer syndrome), although these are essential to understanding cranial vault expansion and hydrocephalus treatment in these syndromes. OBJECTIVE: A review of the medical literature was performed, to understand the physiological and pathological growth mechanisms of the posterior fossa in normal infants and infants with craniostenosis related to FGFR2 mutation. DISCUSSION: Of the various techniques for measuring posterior fossa volume, direct slice-by-slice contouring is the most precise and sensitive. Posterior fossa growth follows a bi-phasic pattern due to opening of the petro-occipital, occipitomastoidal and spheno-occipital sutures. Some studies reported smaller posterior fossae in syndromic craniostenosis, whereas direct contouring studies reported no difference between normal and craniostenotic patients. In Crouzon syndrome, synchondrosis fusion occurs earlier than in normal subjects, and follows a precise pattern. This premature fusion in Crouzon syndrome leads to a stenotic foramen magnum and facial retrusion.
BACKGROUND: The growth of the posterior fossa in syndromic craniostenosis was studied in many papers. However, few studies described the pathophysiological growth mechanisms in non-operated infants with fibroblast growth factor receptor (FGFR) type 2 mutation (Crouzon, Apert or Pfeiffer syndrome), although these are essential to understanding cranial vault expansion and hydrocephalus treatment in these syndromes. OBJECTIVE: A review of the medical literature was performed, to understand the physiological and pathological growth mechanisms of the posterior fossa in normal infants and infants with craniostenosis related to FGFR2 mutation. DISCUSSION: Of the various techniques for measuring posterior fossa volume, direct slice-by-slice contouring is the most precise and sensitive. Posterior fossa growth follows a bi-phasic pattern due to opening of the petro-occipital, occipitomastoidal and spheno-occipital sutures. Some studies reported smaller posterior fossae in syndromic craniostenosis, whereas direct contouring studies reported no difference between normal and craniostenotic patients. In Crouzon syndrome, synchondrosis fusion occurs earlier than in normal subjects, and follows a precise pattern. This premature fusion in Crouzon syndrome leads to a stenotic foramen magnum and facial retrusion.