Assessment of bone healing after Le Fort I osteotomy with 3-dimensional computed tomography

Abstract

Purpose The purpose of this study was to examine bone healing after Le Fort I osteotomy in Class III patients. Patients and methods The study group consisted of 18 Japanese patients with mandibular prognathism with and without asymmetry, maxillary retrognathism or open bite. A total of 36 sides were examined. Le Fort I osteotomy was performed without a pterygoid osteotome, with an ultrasonic curette used to remove interference at the pterygomaxillary region. Titanium plates (Universal Mid-face fixation module, Stryker, Freiburg, German) were used for four patients, absorbable plates (poly- l-lactic acid (PLLA): NEOFIX ®, Gunze, kyoto, Japan) were used for four patients and other absorbable plates (uncalcined and unsintered hydroxyapatite and poly- L-lactic acid (uHA/PLLA): super FIXSORB ®MX, Takiron Co. Ltd, Osaka, Japan) were used for 10 patients, in the same manner. Postoperative computed tomography (CT) was analyzed for all patients pre-operatively and 1 year postoperative. The anterior and lateral areas between the maxillary segments were measured with 3-dimensional (3D) CT. Bone healing at the pterygomaxillary region was also assessed. Results There were no significant differences in the area of bone defect healing among the plate types. The areas of bone defect after 1 year were significantly smaller than that immediately after surgery on the right side ( p = 0.0145) and left side ( p = 0.0010) in the frontal view and right side in the lateral view ( p = 0.0118). Bone healing at the pterygomaxillary junction was found in all cases without artificial pterygoid plate fracture. Fourteen of 22 sides with artificial pterygoid plate fracture by an ultrasonic curette showed bone continuity between the pterygoid plate and posterior part of maxilla. Conclusion This study suggested that bony healing could occur in spaces between the segments of maxilla and pterygomaxillary regions as well as the region of the anterior and lateral walls in the maxilla, but it is not always complete within 1 year after Le Fort I osteotomy.