Background: Unicoronal synostosis is characterized by ipsilateral, superior and posterior displacement of the frontal bone, supraorbital ridge, and orbit, as well as contralateral compensatory changes. Fronto-orbital advancement and reshaping in the first year of life is the generally accepted treatment. This study examines long term outcomes following surgical correction, including complication rate, maintenance, timing and quality of correction, as well as incidence of relapse, and the need for secondary surgery.

Methods: All patients presenting to the senior author (LAW) with unilateral coronal synostosis from 1971 to 2000, and subsequently treated with unilateral fronto-orbital advancement were included in the study. Hospital and outpatient records were reviewed. Exclusion criteria included multi-sutural synostosis, the presence of an eponymous syndrome, and previous surgical correction. Outcomes were considered satisfactory if re-advancement, or other major bony procedures were neither performed nor recommended. Statistical analysis, including analysis of variance (ANOVA) was performed to determine whether any significant differences could be identified within segments of the study group.

Results: A review of the senior author's database yielded 81 patients. Average age at first surgery was 11.3 months (1.5 – 71). Overall complication rate was 27.16%. The mean follow up over the study period was 61 months (1-234). During the follow up period, an overall relapse rate of 72.8% was recorded. The mean interval between surgery and relapse was 42.91 months (6-183). Sixteen patients (20%) had minor or major re-operations to correct secondary deformities. Overall, satisfactory results after primary surgical correction were achieved in 90.3% of cases. Subgroup analysis was performed based on the age at first surgery. The complication rates for patients 0-6 months old, 6-12 months old, and those 12 months of age and older at first surgery were 13.3%, 45.7%, and 34.5% respectively, and these differences were significant. Secondary surgery was performed in 42.9% of patients whose first surgery was at 0-6 months of age, 8.3% of patients 6-12 months of age, and 24.1% of patients 12 months of age and older. The low rate of re-operation for patients initially treated at 6-12 months of age was significantly different compared to both the early (p = 0.02) and late (p = 0.10) primary surgery groups. When comparing the overall surgical result, patients 0-6 months of age, 6-12 months of age, and those 12 months of age and older had satisfactory results 86.6%, 94.6% and 89.7% of the time, respectively.

Conclusions: Fronto-orbital advancement is an effective method of treatment for surgical correction of unilateral coronal synostosis based on this large series of patients. Despite the majority of patients showing some relapse over time, relatively few patients required secondary surgical correction. Based upon the results as a factor of age at primary correction, patients repaired at 6-12 months of age had the least relapse and need for secondary surgery out of the three groups, although their complication rate was higher than their younger counter parts. Given the modest nature of these complications, the data supports primary surgical correction at 6-12 months of age. It is at this age that the craniofacial skeleton is both mature enough to have adequate structural integrity, and young enough for rapid brain expansion to drive craniofacial skeletal growth.

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