Nasolabial Changes Following Double Jaw Surgery

Background: This study aimed to analyze 3-dimensional nasolabial soft tissue changes following double jaw surgery with Le Fort I maxillary advancement and relate them to underlying surgical movements. Methods: Pre- and post-surgical cone-beam computed tomography images of 37 maxillomandibular surgery patients with >= 2mm of advancement at A-point were analyzed. Lateral cephalograms were constructed to determine horizontal and vertical surgical movements and 3-dimensional facial images were created from the CBCTs to calculate linear and angular changes. Results: Alar base width increased 1.9 mm, nasal tip protrusion decreased 0.74 nun, the upper lip flattened 7.71 degree and increased 0.9 mm in length, nasal tip was displaced 2.47 mm superiorly causing an increased concavity of 5.52 degree for the overall dorsal surface and 3.99 degree at the supratip break angle (SBA), nasal tip angle decreased 2.16 degree and nasolabial angle decreased 7.37 degree. Correlations were found between underlying surgical movements and nasal tip protrusion, SBA, nasolabial angle (NLA), and nasal tip elevation (NTE). Multiple linear regression equations were calculated to predict changes in SBA from horizontal change at A-point, NLA from horizontal change at B-point, and NTE from the change at A-point horizontally and U1-tip vertically. Conclusion: Double jaw surgery with maxillary advancement has significant effects on nasolabial anatomy.