ABNORMALITIES OF THE CRANIAL BASE IN SYNOSTOTIC FRONTAL PLAGIOCEPHALY

Skeletal abnormalities of the cranial base in various craniosynostoses are well known. Cranial base angulation has been documented in synost otic frontal plagiocephaly-''unilateral coronal synostoses,'' We analy zed four infants with synostotic frontal plagiocephaly, focusing on co mputed tomographic images through the cranial base, The scans were per formed on a GE advantage spiral with 1.5-mm images. The anatomical str uctures examined were length of the foramina ovale, length of the eust achian tubes, and sphenotemporal angles. Ratios for these measures wer e calculated comparing the normal and synostotic sides. The foramen ov ale was 21% longer on the synostotic side; the eustachian canal was 11 % shorter on the synostotic side. The average sphenotemporal angle on the synotic side was 121 degrees compared with 149 degrees on the nons ynostotic side. Deformities of the cranial base (i.e., elongation of s tructures anterior to the synostosis and shortening of the structures posterior to the synostosis) can be documented before surgical correct ion of synostotic frontal plagiocephaly. Follow-up computed tomographi c studies will permit study of the effect of fronto-orbital advancemen t and modeling on these basilar abnormalities.