Maxillary Total Elongation Surgery using 3D Virtual Surgery, CAD/CAM and 3D Printing Technology: Surgical Convenience and Accuracy

Abstract

After Le Fort I osteotomy was first performed by von Langernbeck in 1859, there has been many improvements since. Research on and development of Le Fort I osteotomy procedure has shown downward movement of the maxilla to exhibit lowest stability and accuracy. However, maxillary downgraft movement is necessary in orthognathic patients with insufficient vertical length of the maxilla, but fixation of the maxilla after elongation is often very inaccurate. In this study, the authors utilized 3D virtual surgery, CAD/CAM-assisted 3D printing technology to overcome such limitations of maxillary total elongation. In addition, accuracy at 7 different landmarks from superimposition of virtual simulation data and postoperative Cone-beam computed tomography (CBCT) data were measured. Although posterior maxilla exhibited bigger range of errors, an error of <1 mm was measured at all 7 landmarks. Operation time was greatly shortened with cutting guides and customized plates. Although this study is a single-case study, this study shows increased accuracy and efficacy from application of 3D virtual surgery, CAD/CAM, and 3D printing technology.

Treatment Strategy for Condyle/Ramus Deficiency Using 3D Virtual Surgery and CAD/CAM Technologies; Total Joint Replacement or Inverted-L Osteotomy

“…For ILO, (1) VSP and CAD/CAM technology can quantify the amount of osteotomy gap between the proximal and distal segments and determine the feasibility of the iliac bone grafting; (2) maxillomandibular complex can be accurately positioned according to the surgical plan with CAD/CAM-printed surgical guides and customized osteosynthesis plates;19 (3) prevention of condyle sagging or displacement, related to the inaccurate transfer of surgical plan, is possible; and (4) increase in the number, length, and thickness of osteosynthesis plates can resist stress concentration and prevent unwanted screw loosening or breakage or deformation of the osteosynthesis plates, resulting in robust fixation to the segments of the mandible 10,19…”

“…For example, in TJR, (1) the accurate 3-dimensional positions of the fossa and condylar parts can be determined with considerations of physiological movement of TMJ and the patient’s anatomic considerations; (2) optimal screw locations can be determined according to appropriate bone quality of the mandible;19 (3) accurate removal of the bulged portions and concurrent prevention of unnecessary grinding of the mandible are possible with the evaluation of the lateral surface of the ramus; (4) precise adaption of the condyle prosthesis to the ramus surface can avoid screw loosening and an ultimate failure; and (5) risk of nerve injury due to screw fixation to the ramus can be reduced compared with the risk for the stock prosthesis 17,20…”

Bone Tissue Engineering (BTE) of the Craniofacial Skeleton, Part II: Translational Potential of 3D-Printed Scaffolds for Defect Repair

“…6A), allows for a maximized interaction of the interface between scaffold and defect that is superior to a noncustomizable autograft 3 . Most importantly, CAD/CAM–assisted 3D printing of customized constructs for CMF surgical defect repair continues to be explored as an alternative to traditional bone grafting procedures 4,5,14,18,19,60–63 . This has been demonstrated in a Göttingen minipig model (Fig.…”

“…Utilization of biocompatible scaffolds also overcomes the drawbacks of traditional alloplastic materials used in CMF reconstruction, which are prone to infection and eventual extrusion 64–66 . Ultimately, patients and surgeons have reported improved esthetic outcomes and shorter operative time without a compromise in function 2,4,67 …”

“…Image acquisition either by cone beam computed tomography (CBCT), computed tomography, or magnetic resonance imaging, forms the core of the 3D printing workflow in clinical applications and enables accurate representation of the regions of interest. Subsequently, a surgical visual treatment objective realization precisely guides surgical planning and mediates patient expectations of desired results 2–8 . An additional clinical application of CAD/CAM technologies includes the evaluation of stress distribution patterns of novel constructs with surrounding bone utilizing Finite Element Analysis 9 .…”