Trigonocephaly (metopic synostosis). Clinical, surgical and anatomical concepts.

The clinical features, surgical and anatomical concepts based on an evaluation of the development of the anterior cranial fossa in metopic synostosis are discussed. Thirteen cases of trigonocephaly of infancy during last 4 years are described. Five children were mentally retarded. A more marked triangular cranial configuration with acute nasopterional angle was associated with more severe mental retardation and other unfavorable conditions, including cardiopulmonary disorders and chromosome anomalies. From a quantitative analysis of the anterior cranial fossa development obtained from CT measurement in comparison with values in normal infants, the following procedures appeared to be important: (1) correction of acute nasopterional angle, achieving a flat forehead; (2) forward advancement of both pterions and anterolateral parts of the frontal bones, rebuilding the orbital roof and frontal eminences; (3) shortening of the overgrown midline structure by removal of the bony ridge of the metopic suture. Our procedure on the basis of these measurements for determination of surgical intervention is described.