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.