Metopic Synostosis (Trigonocephaly)

Metopic synostosis is more common than previously recognized. Today metopic synostosis represents 20-25% of all isolated craniosynostosis. The head shape that results from metopic synostosis is called trigonocephaly because the back of the head is broad and flat and the forehead is narrow and pointed. The metopic suture provides width to the forehead. When it closes prematurely the forehead is very narrow with a prominent vertical ridge and the eye sockets (orbits) are abnormally close together. 

This figure shows the position of the closed metopic suture indicated by the red arrow. Note the narrow forehead, the midline vertical ridge in the position of the closed metopic suture and decreased space between the eye sockets.

This figure shows the position of the closed metopic suture indicated by the red arrow. Note the narrow forehead, the midline vertical ridge in the position of the closed metopic suture and decreased space between the eye sockets.

This figure shows the position of the closed metopic suture indicated by the red arrow. Note the triangular shape of the skull with a narrow forehead, a midline vertical ridge in the position of the closed metopic suture and a broad flat back of the head.

This figure shows the position of the closed metopic suture indicated by the red arrow. Note the triangular shape of the skull with a narrow forehead, a midline vertical ridge in the position of the closed metopic suture and a broad flat back of the head.

This figure shows an infant with metopic craniosynostosis. Note the very narrow appearance to the forehead and the abnormal shape to the upper portion of the eye sockets. This infant also has close set eyes which is characteristic of metopic craniosynostosis. Note the triangular shape of the skull with a narrow forehead, a midline vertical ridge in the position of the closed metopic suture and a broad flat back of the head.

It is common for patients to be referred to me for evaluation for metopic craniosynostosis because of the midline ridge. The metopic suture normally closes between 6-9 months of age. When any suture closes it tends to thicken. If the head shape is otherwise normal and the child is age 6 months or older with a midline ridging of the forehead, it is unlikely that they have metopic craniosynostosis. If you still have concerns you should be seen by a craniofacial surgeon.

The severity of head shape and appearance changes in metopic craniosynostosis can vary. These changes can range from thickening of the suture with mild narrowing of the forehead to the most severe form, with a severely pointed forehead, ridge, close set eyes and a triangular head shape. Why there is such variability is not clear. It is possible that the severity relates to the timing of suture closure during pregnancy. Regardless, if you have concerns for metopic synostosis you should be evaluated by a craniofacial surgeon. In clear cut cases of severe disease, the concerns for elevated pressure that can occur in the skull (about 15%) and the appearance issues that will result from the deformity make the decision to operate easier to make. For those patients with moderate severity, you will have to discuss the functional and appearance issues with the surgeon to determine the appropriate treatment for your child. 

 

Metopic craniosynostosis is typically treated with fronto-orbital advancement (FOA). The goal of treatment is to restore a normal contour to the forehead and upper portion of the eye sockets. This procedure is done at 9-12 months of age. Read more about fronto-orbital advancement.

The goals of fronto-orbital advancement in metopic synostosis are rounding and widening of the forehead and head and normalizing the shape and position of the upper portion of the eye sockets (orbits).

The goals of fronto-orbital advancement in metopic synostosis are rounding and widening of the forehead and head and normalizing the shape. This figure shows a patient's head shape before and after frontoorbital advancement (FOA) as seen when looking down on the top of the head. Note the profound improvement in the shape of the forehead.

The goals of fronto-orbital advancement in metopic synostosis are rounding and widening of the forehead and head and normalizing the shape. This figure shows a patient's head shape before and after frontoorbital advancement (FOA) as seen when looking down on the top of the head. Note the profound improvement in the shape of the forehead.

This figure shows a patient's forehead shape before and after frontoorbital advancement (FOA) as seen when looking down on the top of the head. Note the widening of the forehead and normal appearance in the shape and position of the upper portion of the eye sockets (orbits).