Computer Techniques In Analysis And Application Of L-shaped Reduction Malarplasty

Objectives1. This study aim to evaluate the positional change of malar eminence after L-shaped reduction malarplasty based on photogrammetric analysis.2. To evaluate and analyze the morphological change of craniofacial structures based on 2 dimensional and 3 dimensional CT images, respectively.3. To apply computer techniques in patients with mild zygomatic asymmetry treated with unilateral reduction malarplasty to improve surgical accuracy and reduce perioperative risks.Methods1. Standard photographs of patients was taken preoperatively and postoperatively. Photogrammetric analysis of malar contour was developed and performed using graphics software. The relative parameters of the malar eminence were measured in the photographs of presurgical, postsurgical and beautiful group respectively to quantitatively evaluate the positional change of malar eminence after L shaped reduction malarplasty.2. Based on cephalometric principles, digitalized three dimensional and two dimensional CT images were used to evaluate the change of bony parameters of the zygomatic complex.3. Computer techniques was applied to reconstruct three dimensional ct images, to plan and mimic osteotomies, to produce surgical template for intraoperative guidance, and to evaluate the surgical outcome.Results1. The malar eminence showed a significant decrease in prominence between the presurgical and postsurgical group without a significant change in height. The postsurgical prominence of malar eminence was closed to the value of attractive group. Facial attractiveness of patients increased significantly after surgery.2. Consistent results was concluded from measurement of 2D and 3D CT images. The prominence, width and other related parameters of zygomatic complex was significantly refined after L shaped reduction malarplasty. The reduction in zygomatic arch width gradually increased from the most lateral point of the zygomatic arch towards the malar prominence and became notable in the anterior two-thirds of the zygomatic arch.3. With application of computer techniques in patients with mild zygomatic asymmetry treated with unilateral reduction malarplasty, zygomatic asymmetry were corrected in all the patients without complications. The postoperative 3D images found minimal differences with preoperative design.Conclusions1. We devised a simple and intuitive method for the photographic measurement of the malar contour. Reduction malarplasty with a modified L-shaped osteotomy resulted in a notably reduced malar prominence without obvious downward displacement of malar eminence. The aesthetic result of surgery was good.2. Reduction malarplasty with a modified L-shaped osteotomy resulted in a notable reduction in prominence, width and other bony parameters of zygomatic complex. L-shaped reduction malarplasty was most suitable for those with prominence of zygoma body with or without protusion of anterior part of zygomatic arch.3. Computer techniques were successfully applied in preoperative surgical design, surgical implementation and postoperative evaluation in patients with mild zygomatic asymmetry treated with unilateral malar reduction. Our experiences indicate that surgical accuracy and efficiency could be improved with minimal operative risk by using the proposed methodology.