Decision-Making for Le Fort III Distraction in Syndromic Craniosynostosis With Extreme Calvarial Bone Deficiency

BACKGROUND: Rigid external distraction after Le Fort III or monobloc osteotomy depends on secure cranial pin fixation. Previous vault reconstruction may leave thin, discontinuous, or immature calvarial bone, creating a conflict between the need for major midface advancement and the risk of pin loosening, depressed fracture, and intracranial penetration. METHODS: We describe 2 children with syndromic craniosynostosis, severe midface retrusion, and marked calvarial bone deficiency after previous cranial operations. Preoperative thin-section computed tomography and three-dimensional models were used to evaluate native bone, reconstructed regions, defects, and potential pin trajectories. Operative candidacy was determined by whether multiple safe fixation sites could be identified. RESULTS: A 6-year-old girl with Crouzon syndrome and 2 previous calvarial reconstructions underwent Le Fort III osteotomy and rigid external distraction. Fixation was achieved by distributing shallow pins across relatively preserved native bone, orienting each pin perpendicular to the local surface, and monitoring stability during conservative distraction. No pin loosening or intracranial penetration occurred, and satisfactory midface advancement with improvement in proptosis was achieved. A 4-year-old girl with previous vault reconstruction and ventriculoperitoneal shunting had insufficient safe cranial bone, particularly in the temporal regions. External distraction and monobloc advancement were deferred; airway support, imaging surveillance, multidisciplinary follow-up, and delayed reconstruction were selected. CONCLUSIONS: Extreme calvarial bone deficiency should be treated as a primary contraindication assessment rather than a minor technical obstacle. Three-dimensional mapping of native bone, distributed perpendicular fixation, conservative loading, and willingness to defer surgery are central to preventing catastrophic pin-related complications.