Soft Tissue Changes Following LeFort III and Monobloc Frontofacial Advancement: A Comparative Photogrammetric Analysis
Dillan F Villavisanis1, Daniel Y Cho1, Satvika Kumar1, Jessica D Blum1,Jordan W Swanson1, Scott P Bartlett1, Jesse A Taylor1
1Division of Plastic & Reconstructive Surgery, Children's Hospital of Philadelphia. Philadelphia, PA, USA
Background: Patients with syndromic craniosynostosis benefit both aesthetically and functionally from surgical advancement of the midface and forehead. Based on the severity of the deformity and functional needs, surgeons may select monobloc frontofacial advancement to simultaneously advance the forehead and midface, or a staged approach with fronto-orbital advancement to address the anterior cranial vault followed by LeFort III for midface advancement. Both procedures have proven efficacy for skeletal changes; however, their effect on soft tissues has not been quantified. The aim of this study was to perform a quantitative photogrammetric comparison of the soft tissue changes achieved with monobloc and LeFort III midface advancements.
Methods: Patients undergoing LeFort III and monobloc advancements at our institution with frontal and lateral pre- and postoperative clinical photography were included in this retrospective study. ImageJ was used to measure soft tissue anatomy in pixels, including nasal length and width, intercanthal distance, and palpebral fissure height and width. To account for differences in photographic magnification, ratios were established by dividing soft tissue anatomic measurements in pixels by facial height or width in pixels. Facial convexity was quantified by calculating the angle between sellion (radix), subnasale, and pogonion on lateral photographs. Canthal tilt was determined by calculating the angle between: 1) a line passing through the lateral and medial canthi and 2) a line adjacent to the inferior palpebra and parallel to the nasal ala. Pre- and postoperative changes were compared between the procedural groups with unpaired t-tests.
Results: Forty-three patients (eighteen Crouzon, ten Pfeiffer, ten Apert, five other) undergoing monobloc (n = 13) and Le Fort III or Le Fort II with zygomatic repositioning (n = 30) were analyzed preoperatively and 10.8±5.5 months postoperatively. Patients undergoing Le Fort procedures achieved significantly greater changes in facial convexity (27.2°) compared to patients undergoing monobloc procedures (13.9°) (p = 0.011). Patients undergoing Le Fort procedures achieved significantly better changes in canthal tilt symmetry (0.1% increase in symmetry) compared to those undergoing monobloc procedures (1.9% decrease in symmetry) (p = 0.037). Patients demonstrated comparable changes in other soft tissue anatomy (all p > 0.05).
Conclusions: Both subcranial LeFort and monobloc frontofacial advancements resulted in significant changes in the soft tissues, with patients underoing LeFort procedures achieving superior improvements in facial convexity and canthal tilt symmetry. This may be attributed to greater degree of freedom by separate movement of the midface relative to the forehead.
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