The changing epidemiologic spectrum of single-suture synostoses.

PURPOSE: Classic literature indicates an infrequency of metopic craniosynostosis (3 to 10 percent) compared to other single-suture craniosynostosis. Recent observation challenges these conceptions, warranting long-term demographic analysis.
METHODS: Syndromic craniofacial dysostoses and multiple suture involvement were exclusion criteria, leaving only single suture synostoses treated between 1975 and 2004. A chart review was performed and patient information recorded. Chi square analysis and Fisher's exact were used to determine differences in patient characteristics. A Moran's I statistic was used to determine differences in spatial means and whether changes in incidence of single-suture synostoses over time are a function of regional phenomena.
RESULTS: Over 800 patients presented to The Children's Hospital of Philadelphia with a diagnosis of single-suture synostosis. There was an outpacing of sagittal suture involvement over other sutures. Data demonstrate a decrease in unicoronal synostosis and an increase in metopic synostosis (p = 0.011). Geostatistical analysis reveals increasing separation between populations over the study period: 9.8 miles in the first 5 years to 20.8 miles in the last 5 years. Metopic maternal age increased between 1975-1989 and 1990-2004 (p = 0.002, 0.0002), while unicoronal maternal age did not. The proportion of male patients increased considerably in the metopic group compared to unicoronals from 1990-2004 (p = 0.0001), as did the proportion of syndromic metopic patients (p = 0.02). Plausible etiologies for these epidemiological shifts are discussed.
CONCLUSIONS: Metopic synostosis is on the rise. Changing demographic bases and increasing proportions of syndromic patients may be clues to the etiology of this epidemiologic event.