Objective: To propose landmarks and a new coordinate system to aid three-dimensional cephalometric analysis of adolescent cleft lip and palate (CLP) using computed tomography (CT) imaging.
Methods: Sixty-four-row CT images obtained from 52 adolescent patients were retrospectively analyzed with the MIMICS program (MIMICS 10.02; Materialise Technologies, Leuven, Belgium) to determine intrarater reliability of new landmarks for three-dimensional cephalometric analysis before surgery.
Results: Five points were located on each image including the midpoint between both uppermost external points of the external auditory meatus (EAM), the center of the sella turcica (sella, S), the most anterior point on the nasofrontal suture in the midline (nasion, N), and the right and left lowest points of the lower edge of the orbitale (r/l orbitale, r/l Or). The horizontal reference plane was then determined using EAM and bilateral Or. The sagittal reference plane was defined perpendicular to the horizontal plane, passing through N and S. The coronal reference plane included the EAM landmark and was perpendicular to the sagittal and horizontal planes. All 5 points had high intrarater reliability and proved easy to use in constructing the new coordinate system. The horizontal, sagittal, and coronal reference planes formed by these respective points improved the ease of performing three-dimensional cephalometric analysis of CLP adolescents with CT imaging.
Conclusions: Our 5 landmarks provided reliable CT-guided three-dimensional cephalometric analysis of CLP, allowing for accurate quantitative assessment in adolescents before orthognathic surgery.