Orbit, zygoma, and maxilla growth patterns in Crouzon syndrome.

The facial malformations of Crouzon syndrome involve the entire cranio-orbito-zygomatic region. The detailed sequence of changes in orbit, zygoma, and maxilla over time, the mutual influence among these three anatomical structures, and their relationship with the cranial base were studied to determine the sequence and timing of deformity. Preoperative CT scans of 36 patients with Crouzon syndrome (mean age 10.84±14.70years; 14 male, 22 female) and CT scans of 54 control subjects (mean age 8.53±13.22years; 29 male, 25 female) were divided into five subgroups by age: 0-6 months, 6 months-2 years, 2-6 years, 6-18 years, and 18-62 years. Craniofacial morphometric cephalometrics were analyzed using Materialise software. Crouzon orbit anteroposterior length was shorter before 6 months (P=0.021) and remained shorter into adulthood (P<0.001). Globe projection was greater across all age subgroups (P<0.001), reaching a peak at 6 months to 2 years (P<0.001). The increased medial orbital width was the most remarkable and persistent secondary deformity (P<0.001). The zygoma anterior protrusion was retruded before 6 months of age (P<0.001), but then improved gradually. The width of maxilla was greater by 24% in the Crouzon cohort (P<0.001), with a difference of 16% before 6 months (P=0.024), and was developed earlier than the shortened anteroposterior length. Crouzon high and shallow orbital walls are distinctive. Maxillary widening developed before the malformation of sphenoid. The anteroposterior position of zygoma is likely a principal deformity, rather than a reflection of the intrinsic shape of the bone. Level of Evidence: II.

Anterior convex lateral orbital wall: distinctive morphology in Apert syndrome.

Bony malformations of the orbit and alterations to the soft tissue in Apert syndrome contribute to ophthalmic dysfunction. Recognised structural malformation of the sphenoid and ethmoid sinuses, together with corresponding deformities in the anterior and middle cranial base, are characteristic. Our aim was to explore the underlying structural components of disfigurement and the consequent development of the orbit in patients with Apert syndrome over time by studying 18 preoperative computed tomographic (CT) scans of affected patients and 36 scans from controls. Cephalometric measurements related to the orbit were collected, and analysed with Materialise software. The patients with Apert syndrome had larger than normal external orbital horizontal angles between the ages of 6 months and 2 years. The inside horizontal angle was narrower at 16.36° before 6 months, and continued to decrease into adulthood. The ethmoid and sphenoid side angles in affected patients consistently increased, starting at 7.93% and 14.68% of the external horizontal angle, respectively, during the first 6 months of age, and becoming 20.55% and 11.69%, respectively, in adulthood. In unaffected patients, both angles were less than 3% of the external horizontal angle overall. The orbital vertical angle also changed synchronously, with increasingly wide lateral orbits and shortened anteroposterior orbits. The anterior protrusion of the lateral orbital wall resulted from superior and posterior rotation of a curved, greater wing of the sphenoid, while the widened median orbital wall was caused by the widened ethmoid sinus. These resulted in bony deformities of the orbit, which predisposed to the visual impairments of Apert syndrome.