Age-dependent closure of bony defects after frontal orbital advancement.

BACKGROUND: The ability of the immature skull to spontaneously heal large bony defects created after craniofacial procedures was examined over a 25-year period of craniofacial surgery at the Children's Hospital of Philadelphia.
METHODS: Only patients who underwent frontal orbital advancement and reconstruction, had at least 1 year of documented follow-up, and had the presence or absence of a bony defect documented on clinical examination were included. The sex, age at operation, diagnosis, history of a prior craniectomy, and presence or absence of a postoperative infection were determined for each patient. A variety of statistics were applied to the data.
RESULTS: Eighty-one patients met the inclusion criteria. A statistically significant association between age at operation and closure of bony defect was demonstrated. Children who closed a bony defect after frontal orbital advancement and reconstruction were significantly younger than those children who had a persistent bony defect. Iterative regression analyses demonstrated that a transition point between closure and the inability to close bony defects occurred between 9 and 11 months of age. Closure of bony defects was not statistically associated with sex, prior craniectomy, an FGFR mutation, or a postoperative infection in the regression analysis.
CONCLUSIONS: Healing of bony defects after frontal orbital advancement and reconstruction is significantly related to age at initial operation, with a mean age for closure of less than 12 months. Between 9 and 11 months of age, a change occurs that results in an increasingly lower probability of bony defect closure; thus, all other considerations being equal, initial frontal orbital advancement and reconstruction would ideally take place before this occurs.