On the other hand, the fronto-supraorbital advancement and remodelling and the floating forehead technique create sufficient space for brain growth and result in a normal horizontal axis of the orbits and supraorbital bar. The fronto-supraorbital advancement and remodelling is the most used method nowadays. Over the past few years distraction osteogenesis has been gradually acknowledged since it has a positive effect on hypotelorism. Expanding the distance between the orbits using springs seems to be successful. However, there are discussions whether hypotelorism really needs to be corrected. The minimal invasive endoscopic surgery has been gaining attention since the early 90s, however, it has technical limitations (only strip craniectomy is possible). Attempts have been made to reach beyond these limits. Aesthetic
Aesthetic outcome of metopic  synostosis surgery is persistently good with reoperation hazards below 20%. In 1981 Anderson advised that craniofacial operations for synostosis should be as extensive as necessary after a study of 107 cases of metopic and coronal synostosis. Surgery does not provide a 100% natural outcome, mostly there will be minor irregularities. Reoperations are usually performed on more severe cases (including syndromic metopic synostosis). The hypotelorism  and temporal hollowing are the most difficult to correct: the hypotelorism usually remains under corrected and a second operation is often needed for correction of temporal hollowing. Neurological
The highest rate of neurological problems of single suture synostosis are seen in patients with trigonocephaly. Surgery is performed generally before the age of one because of claims of better intellectual outcome.
Diagnosis
Diagnosis can be characterized by typical facial and cranial deformities.Observatory signs of trigonocephaly are:

a triangular forehead seen from top view leading to a smaller anterior cranial fossa
a visible and palpable midline ridge
hypotelorism inducing ethmoidal hypoplasiaImaging techniques (3D-CT, Röntgenography, MRI) show:

epicanthal folds in limited cases
teardrop-shaped orbits angulated towards the midline of the forehead (surprised coon sign) in severe cases
a contrast difference between a röntgenograph of a normal and a trigonocephalic skull
anterior curving of the metopic suture seen from lateral view of the cranium on a röntgenograph
a normal cephalic index (maximum cranium width / maximum cranium length) however, there is bitemporal shortening and biparietal broadeningThe neuropsychological development is not always affected. These effects are only visible in a small percentage of children with trigonocephaly or other suture synostoses. Neuropsychological signs are:

problems in behaviour, speech and language
mental retardation
neurodevelopmental delays such as attention deficit hyperactivity disorder (ADHD), oppositional defiant disorder (ODD), autism spectrum disorder (ASD), and conduct disorder (CD). Many of these delays become evident at school age. Treatment
Treatment is surgical with attention to form and volume. Surgery usually takes place before the age of one since it has been reported that the intellectual outcome is better. Fronto-supraorbital advancement and remodelling
A form of surgery is the so-called fronto-supraorbital advancement and remodelling. Firstly, the supraorbital bar is remodelled by a wired greenstick fracture to straighten it. Secondly, the supraorbital bar is moved 2 cm. forward and fixed only to the frontal process of the zygoma without fixation to the cranium.