Evaluation of condylar morphology following orthognathic surgery on digital panoramic radiographs. Could methodology influence the range of "normality" in condylar changes?

Objectives: To evaluate the morphological condylar changes following orthognathic surgery by using a rapid and reliable computational method on panoramic radiographs. Methods: Digital panoramic radiographs of 45 patients who underwent bilateral sagittal split osteotomy (alone or associated with a Le Fort I osteotomy) between 2007 and 2010 were analysed. Calculation of the area, perimeter and height of 90 condyles was performed by using a specific computational method. Measurements were taken before surgery (m₁), 1 day after surgery (m₂) and 1 year after surgery (m₃). The evolution of each index was analysed using paired t-tests between measures before and 1 day after surgery (m₁ - m₂) and measures before and 1 year after surgery (m₁ - m₃). The changes in the condylar area, perimeter and height were examined using the Bland and Altman plotting method. Results: There were no statistically significant changes in the mean condylar area, perimeter or height between m₁ and m₂ or between m₁ and m₃. The Bland and Altman plots for each index showed that a very limited number of condyles increased or decreased in area, perimeter and/or height outside the boundaries of the measurement error. Given the impossibility for a condyle to increase in size, these results are considered to represent the limits of the computational method used. Conclusions: This study demonstrated that there were no significant morphological condylar changes at the 1-year follow-up following surgery and that the range of normality in condylar changes could be influenced by the methodology used. [ABSTRACT FROM AUTHOR]