This decision is made because then the neurocranium and orbits have developed to 90% of their eventual form. Furthermore, the dental placement in the jaw has been finalized around this age. Facial bipartition with median faciotomy
To correct the rather prominent hypertelorism, wide nasal root and midline cleft in FND, a facial bipartition can be performed. This surgery is preferred to periorbital box-osteotomy because deformities are corrected with a better aesthetic result.During the operation, the orbits are disconnected from the skull and the base of the skull. However, they remain attached to the upper jaw. Part of the forehead in the centre of the face is removed (median faciotomy) in the process. Then, the orbits are rotated internally, to correct the hypertelorism. Often, a new nasal bone will have to be interpositioned, using a bone transplant. Complications of this procedure are: bleeding, meningitis, cerebrospinal fluid leakage and blindness. Rhinoplasty
Structural nasal deformities are corrected during or shortly after the facial bipartition surgery. In this procedure, bone grafts are used to reconstruct the nasal bridge. However, a second procedure is often needed after the development of the nose has been finalized (at the age of 14 years or even later). Secondary rhinoplasty is based mainly on a nasal augmentation, since it has been proven better to add tissue to the nose than to remove tissue. This is caused by the minimal capacity of contraction of the nasal skin after surgery.In rhinoplasty, the use of autografts (tissue from the same person as the surgery is performed on) is preferred.
Frontonasal dysplasia (FND) is a congenital malformation of the midface. For the diagnosis of FND, a patient should present at least two of the following characteristics: hypertelorism (an increased distance between the eyes), a wide nasal root, vertical midline cleft of the nose and/or upper lip, cleft of the wings of the nose, malformed nasal tip, encephalocele (an opening of the skull with protrusion of the brain) or V-shaped hair pattern on the forehead. The cause of FND remains unknown. FND seems to be sporadic (random) and multiple environmental factors are suggested as possible causes for the syndrome. However, in some families multiple cases of FND were reported, which suggests a genetic cause of FND. Classification
There are multiple classification systems for FND. None of these classification systems have unraveled any genetic factors as the cause of FND. Yet, all of them are very valuable in determining the prognosis of an individual. In the subheadings below, the most common classifications will be explained. Sedano classification
This is a classification based on the embryological cause of FND. De Myer
This classification is based on the morphologic characteristics of FND, that describes a variety of phenotypesBoth of these classifications are further described in table 1. This table originates from the article ‘Acromelic frontonasal dysplasia: further delineation of a subtype with brain malformations and polydactyly (Toriello syndrome), Verloes et al. Signs and symptoms
Midfacial malformations can be subdivided into two different groups. One group with hypertelorism, this includes FND.