Technical procedures for template-guided surgery for mandibular reconstruction based on digital design and manufacturing

Abstract

BackgroundThe occurrence of mandibular defects caused by tumors has been continuously increasing in China in recent years. Conversely, results of the repair of mandibular defects affect the recovery of oral function and patient appearance, and the requirements for accuracy and high surgical quality must be more stringent. Digital techniques — including model reconstruction based on medical images, computer-aided design, and additive manufacturing — have been widely used in modern medicine to improve the accuracy and quality of diagnosis and surgery. However, some special software platforms and services from international companies are not always available for most of researchers and surgeons because they are expensive and time-consuming.MethodsHere, a new technical solution for guided surgery for the repair of mandibular defects is proposed, based on general popular tools in medical image processing, 3D (3 dimension) model reconstruction, digital design, and fabrication via 3D printing. First, CT (computerized tomography) images are processed to reconstruct the 3D model of the mandible and fibular bone. The defect area is then replaced by healthy contralateral bone to create the repair model. With the repair model as reference, the graft shape and cutline are designed on fibular bone, as is the guide for cutting and shaping. The physical model, fabricated via 3D printing, including surgical guide, the original model, and the repair model, can be used to preform a titanium locking plate, as well as to design and verify the surgical plan and guide. In clinics, surgeons can operate with the help of the surgical guide and preformed plate to realize the predesigned surgical plan.ResultsWith sufficient communication between engineers and surgeons, an optimal surgical plan can be designed via some common software platforms but needs to be translated to the clinic. Based on customized models and tools, including three surgical guides, preformed titanium plate for fixation, and physical models of the mandible, grafts for defect repair can be cut from fibular bone, shaped with high accuracy during surgery, and fixed with a well-fitting preformed locking plate, so that the predesigned plan can be performed in the clinic and the oral function and appearance of the patient are recovered. This method requires 20% less operating time compared with conventional surgery, and the advantages in cost and convenience are significant compared with those of existing commercial services in China.ConclusionsThis comparison between two groups of cases illustrates that, with the proposed method, the accuracy of mandibular defect repair surgery is increased significantly and is less time-consuming, and patients are satisfied with both the recovery of oral function and their appearance. Until now, more than 15 cases have been treated with the proposed methods, so their feasibility and validity have been verified.

Validation of a fibula graft cutting guide for mandibular reconstruction: experiment with rapid prototyping mandible model

“…The cutting guide should be designed with a computer program, based on the data obtained from a surgical simulation, and prepared with a three-dimensional (3D) printer and biocompatible materials. [2] The mandible can also be reconstructed with a FFF that is cut without a fibula cutting guide template. In that method, a reconstructed mandibular model, based on preoperative simulation, can be prepared with a 3D printer and used as a reference for cutting the fibula bone and reconstructing the mandible.…”

Maxillomandibular rehabilitation using digital technology assisted with stereolithographic surgical guide and distraction osteogenesis: A case report

“…This system provides the surgeon with a significant advantage in preparing for procedures that are both technically challenging and difficult to plan. Likewise, digital techniques including model reconstruction based on medical images, CAD, and additive manufacturing have been widely used in modern medicine to improve the accuracy and quality of diagnosis and surgery [21]. Moreover, in contemporary dentistry, the use of 3D imaging aided stereolithographic surgical guides has evolved from oral rehabilitation to the construction of definitive nasal prosthesis and handpiece guidance apparatus [22][23][24].…”

Three-dimensional printing in surgery: a review of current surgical applications

“…SLS technologies enable large amounts of focused energy to be directed onto the build substrate allowing for the creation of individual layers, and subsequently parts, from high performance materials such as titanium, stainless steel or custom metal alloys. 9 Focused electron beam sources may also be used to selectively melt base material as a laser alternative.…”