Assessing the corrective effects of facial bipartition distraction in Apert syndrome using geometric morphometrics.
Apert syndrome is a congenital disorder characterized by craniosynostosis and midface hypoplasia. This study looks to identify to what extent bipartition distraction corrects the morphological abnormalities of this condition. Preoperative and postoperative three-dimensional computed tomography (3DCT) scans of 10 patients with Apert syndrome (12-21 years) were identified from the Great Ormond Street Hospital database. To analyse preoperative and postoperative scans, 98 landmarks and 13 normal skulls were used. Principal component analysis (PCA) was used to analyse patterns in the datasets. Within each group, eigenvectors were identified that demonstrated the aspects of the skull where most variations were found. The analysis allowed both global shape measurement and local proportions. Postoperative and normal scans both showed the same first three principal components. Warping from preoperative to postoperative illustrates midface advancement and inward rotation of the orbits. Postoperative to normal warps demonstrate some remaining differences. The reliability of the used land marks varied between 77% and 95% for the highly reproducible landmarks between the two observers. 95% versus 100% were at least acceptable reproducible landmarks. This study allows us to understand the way bipartition distraction corrects the abnormalities of the Apert skull. Analysing the surgical outcome of facial bipartition with geometric morphometrics shows that some major Apert characteristics are corrected. Using the data and the output of further studies, surgical procedures can be adapted in order to achieve a postoperative result closer to the normal population.


METHODS
Therapeutic clinical question Level IV.
Erasmus Medical Center, Maxillofacial Surgery, Rotterdam, The Netherlands.
Genevieve A J C
GA
Crombag
Erasmus Medical Center, Maxillofacial Surgery, Rotterdam, The Netherlands. Electronic address: melanieverdoorn@gmail.com.
Melanie H A S
MH
Verdoorn
Great Ormond Street Hospital, London, United Kingdom; Queen Victoria Hospital, East Grinstead, United Kingdom.
Dariush
D
Nikkhah
Great Ormond Street Hospital, London, United Kingdom.
Allan J T
AJ
Ponniah
Medical Physics Department, University College London, London, United Kingdom.
Clifford
C
Ruff
Great Ormond Street Hospital, London, United Kingdom.
David
D
Dunaway
D000168:Acrocephalosyndactylia / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000601:surgery*; D000293:Adolescent; D059925:Anatomic Landmarks; D016022:Case-Control Studies; D002508:Cephalometry / Q000379:methods; D002648:Child; D005147:Facial Bones / Q000002:abnormalities / Q000000981:diagnostic imaging* / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008297:Male; D061330:Multidetector Computed Tomography / Q000379:methods*; D019857:Osteogenesis, Distraction / Q000379:methods; D011182:Postoperative Care / Q000379:methods; D011300:Preoperative Care / Q000379:methods; D011857:Radiographic Image Interpretation, Computer-Assisted; D019651:Plastic Surgery Procedures / Q000379:methods; D015203:Reproducibility of Results; D016896:Treatment Outcome
Apert syndrome; Facial bipartition; Geometric morphometrics; Principal component analysis