[3-dimensional position changes of periorbital structures after midface distraction osteogenesis]

Area of Science:

• Craniofacial surgery
• Orthognathic surgery
• Pediatric plastic surgery

Background:

• Crouzon syndrome causes midface hypoplasia, impacting facial aesthetics and function.
• Midface distraction osteogenesis is a surgical technique to correct these deformities.

Purpose of the Study:

• To quantify 3-D positional changes of periorbital structures after midface distraction osteogenesis in Crouzon syndrome patients.
• To compare post-operative changes with normal controls.

Main Methods:

• Retrospective analysis of CT data from 8 Crouzon syndrome patients (average age 11.9 years) before and one year after Le Fort III osteotomy with midface distraction.
• 3-D image reconstruction and establishment of a coordinate system.
• Measurement and comparison of pre- and post-operative positions of key orbital landmarks (SOr, IOr, MOr, LOr, AO, PO, rectus muscle insertions).

Main Results:

• Significant anterior and inferior displacement of the inferior orbit point (IOr), median orbit point (MOr), and lateral orbit point (LOr).
• The anterior ocularis point (AO) showed reduced inter-orbital distance but no significant vertical or depth changes.
• Inferior Rectus muscle insertions moved anteriorly and inferiorly.

Conclusions:

• Le Fort III osteotomy with midface distraction effectively repositions medial, lateral, and inferior periorbital bone structures anteriorly and inferiorly in Crouzon syndrome.
• Eyeball position demonstrates limited sagittal changes, with minor medial and downward movements and slight anterior-upward rotations.