Congenital Syndromes

This collection of syndromes has proved to be an exciting area of investigation for plastic surgeons and other researchers. Surgeons currently have better tools to diagnose and investigate these syndromes, and they are now better understood. Most exciting of all, more sophisticated treatment methods have evolved over the past 20 years.

Crouzon Syndrome

Crouzon syndrome was first described in 1912.

Inheritance

Inheritance is autosomal dominant with virtually complete penetrance. It is caused by multiple mutations of the fibroblast growth factor receptor 2 gene, FGFR2 (Gorry, 1995; Steinberger, 1995).

Features

Features of the skull are variable. The skull may have associated brachycephaly, trigonocephaly, or oxycephaly. These occur with premature fusion of sagittal, metopic, or coronal sutures, with the coronal sutures being the most common. In addition, combinations of these deformities may be seen (Kreiborg, 1982). See Image 1.

The orbits are shallow with resulting exorbitism, which is due to anterior positioning of the greater wing of the sphenoid. The middle cranial fossa is displaced anteriorly and inferiorly, which further shortens the orbit anteroposteriorly. The maxilla is foreshortened, causing reduction of the orbit anteroposteriorly. All these changes result in considerable reduction of orbital volume and resultant significant exorbitism. In severe cases, the lids may not close completely. The maxilla is hypoplastic in all dimensions and is retruded. This decreases the anteroposterior length of the orbital floor.

The upper dental arch is narrowed and retruded, which yields a class III malocclusion. Premature contact of the molars also may be present, resulting in an anterior open bite. This may cause the mandible to be rotated downward and backward. The chin and malars are hypoplastic.

Investigations

Examination of the eyes by an ophthalmologist is essential to assess for papilledema, which indicates elevated intracranial pressure. Another finding may be optic atrophy; fortunately, this is rare.

Radiological examination

This consists of standard radiology to produce anteroposterior, lateral, and cephalometric views. The information gained is the position of the maxilla relative to the mandible. This is class III, with the upper teeth lying behind the lower teeth when they are in occlusion. Patients show evidence of elevated intracranial pressure and have "paw marking" of the skull due to the gyri of the brain indenting and thinning the calvaria, with, in severe cases, erosion (see Image 2). The fusion of the involved sutures can be seen.

A CT scan helps confirm the findings of standard radiographs and provides information on ventricular size. Three-dimensional CT scans can be produced but yield no more information than standard scans, although suture fusion can be graphically displayed.

General assessment

Other abnormalities are sought, and the child's mental development is carefully assessed. An orthodontist should see the child and initiate treatment when indicated.

Apert Syndrome

In nearly all patients with Apert syndrome, the cause is 1 of 2 FGFR2 mutations involving amino acids (Ser252Trp, Pro253Arg). The condition is inherited in an autosomal dominant mode.

Craniosynostosis is present, characterized by brachycephaly and, frequently, turricephaly; the anterior fontanelle is enlarged (Kreiborg, 1991). The maxilla is hypoplastic with a high-arched palate, class III malocclusion with an anterior open bite, and, frequently, a cleft of the soft palate. The mid face is hypoplastic. Together with the retrusion, this causes exorbitism. Complex syndactyly of the hands and feet is present. It is symmetric, and other limb anomalies (eg, shortening) may be observed. The syndactyly may show fusion of the second and forth fingernails, which also may be seen in the toes (Green, 1982). See Image 3. Upper eyelid ptosis with an antimongoloid slant may be seen. Blindness may be present. Overall, the deformity is worse than that of Crouzon syndrome.

Pfeiffer Syndrome

This is an autosomal dominant condition caused by a single recurring mutation (Pro252Arg) of the FGFR1 gene and several mutations involving FGFR2. Patients have craniosynostosis, enlarged thumbs and great toes, and a hypoplastic mid face. The hypoplastic mid face gives the forehead an enlarged appearance. The nose is small. Exorbitism may be present, but it is never as prominent as in persons with Crouzon or Apert syndrome. The condition has been classified into 3 types. Patients with type I have the best long-term prognosis, whereas those with types II and III have neurologic compromise and die young (Cohen, 1993).

Saethre-Chotzen Syndrome

This is an autosomal dominant condition with full penetrance. It is caused by multiple mutations of FGFR2. Craniosynostosis is present, and the hairline is low. Ptosis and brachydactyly are characteristic. The forehead is retruded, giving the appearance of slight exorbitism. The maxilla may or may not be retruded.

Carpenter Syndrome

Patients with this autosomal recessive condition have craniosynostosis, syndactyly of the feet, and short hands and fingers with syndactyly of varying degrees.

Treatment of Craniosynostosis Syndromes

The age at presentation determines the treatment. If possible, provide treatment early and direct it at the cranial vault. The aim is to reduce intracranial pressure, if present, and to prevent visual problems. In addition, the patient's appearance may be improved. The anterior cranial fossa enlargement is a result of frontal lobe growth; at 11 months, the frontal lobes are almost 50% of adult size. The anterior cranial base is at 56% of its total growth at birth and, at 2 years, has achieved 70% of its total growth, probably soon after this full growth is attained. The size and position of the anterior and middle cranial fossa floors are determined by the frontal and temporal lobes. If the anteroposterior growth of the skull base is diminished, this has no affect on mandibular growth.

Early skull base suture fusion results in interference with forward facial growth; thus, release of the affected sutures should provide normal growth. This certainly is the case for the skull, but the mid face remains intruded in patients with Apert or Crouzon syndrome.

Undoubtedly, the best results are achieved in patients with isolated sagittal craniosynostosis. In the past, this was managed with a sagittal strip craniotomy. Currently, making coronal and lambdoid cuts to achieve immediate lateral expansion by hinging the cranial segments outwards is more common. Do not interfere with the lambdoid and coronal sutures.

At 9-11 months in persons with bilateral coronal craniosynostosis, as is seen in Crouzon or Apert syndrome, the frontal area and supraorbital rims are osteotomized separately and advanced to produce a degree of overcorrection with improved frontal contour (Posnick, 1992). This also requires a cut through the orbital roofs and in front of the cribriform plate anteriorly. Laterally in the temporal fossa, the supraorbital rim is advanced using tongue-and-groove techniques for stabilization, although this is now not absolutely necessary because plates and screws (metal or absorbable) are available. The frontal bone is now advanced and plated onto the newly positioned supraorbital rim (see Image 4).

Even with large advancements, scalp closure is always possible. Occasionally, this is aided by galeal scoring. Although this is a standard technique, it is modified as required by the basic anatomy. The patient is monitored using postoperative CT scans to follow the resolution of the dead space (see Images 5-6).

Distraction

Currently, the trend is to advance and fix the frontosupraorbital region and to advance the maxilla subsequently or at the same time, even at an early age, with (Chin, 1997) or without (David, 1990) a distraction apparatus. Although internal distraction devices have been used to push the maxilla forward, with fixation on the temporal area and the use of a rod to apply an anterior pushing on the lateral orbital walls, these have not been uniformly successful. This is mainly because of design faults.

The rigid external distraction device, which is secured by skull fixation, with an anterior pulling force being applied to the maxilla, is more mechanically sound and works well (Figueroa, 1999). It is expensive, the fixation can penetrate the cranium (should the patient fall, striking the side of the head), and the device can become displaced (Rieger, 2001).

Despite this, good forward maxillary movement is obtained in a relatively controlled fashion (see Image 7). The children do not complain about wearing this device. It can be used for persons with Crouzon or Apert syndrome or other conditions that require an osteotomy and forward pull. Whether this is an advantage over the older, well-established, and safe method of advancement osteotomy, stabilization, and bone grafting in one stage remains unproved. In older patients, the latter method probably remains the technique of choice.