Monobloc and bipartition in craniofacial surgery

BACKGROUND: The frontofacial monobloc advancement with osteogenic distraction is increasingly used as a surgical treatment for children with complex craniosynostosis-associated syndromes. However, the subfrontal osteotomy cuts to free the facial skeleton from the skull base require extradural retraction of the frontal lobes. The purpose of this study was to determine the frequency and degree of radiologically identifiable frontal lobe changes and whether any such changes affected the patients' outcome.

METHODS: The clinical records and preoperative and postoperative computed tomography imaging of all patients undergoing monobloc frontofacial distraction advancement (with or without bipartition) were reviewed. A retrospective medical notes review was undertaken to assess any patient or surgically related factors that might predispose to frontal lobe changes and evaluate outcome from surgery. Where available, magnetic resonance imaging scans were reviewed to compare outcome with that on computed tomography.

RESULTS: Fifty cases were identified as suitable for the study. Eighteen patients (36%) had no frontal lobe changes. Thirty-two cases (64%) did have changes that appeared related to the position of maximum retraction during subfrontal osteotomy cuts. There were no changes in the incidence/extent of these changes over time or of any link to the patients' diagnosis, age at surgery, phenotype severity, surgery type, or any surgical or postoperative adverse events. We found no evidence that these changes were responsible for neurologic problems (eg, epilepsy) or reduced cognitive function.

CONCLUSIONS: This study reveals a high incidence of frontal lobe changes demonstrable on neuroimaging following the frontofacial monobloc procedure reflecting the retraction points during surgery. Although no postoperative disability was reported, it is clearly important to consider more detailed neuropsychologic testing and review current surgical techniques to ensure that such changes are kept to a minimum.