Designing CAD/CAM Surgical Guides for Maxillary Reconstruction Using an In-house Approach

Summary

Methods for designing a computer-aided design/computer-aided manufacturing (CAD/CAM) surgical guide are shown. Cutting planes are separated, united, and thickened to easily visualize the necessary bone transfer. These designs can be three-dimensional printed and checked for accuracy.

Abstract

Computer-aided design/computer-assisted manufacturing (CAD/CAM) is now being evaluated as a preparative technique for maxillofacial surgery. Because this technique is expensive and available in only limited areas of the world, we developed a novel CAD/CAM surgical guide using an in-house approach. By using the CAD software, the maxillary resection area and cutting planes and the fibular cutting planes and angles are determined. Once the resection area is decided, the necessary faces are extracted using a Boolean modifier. These superficial faces are united to fit the surface of the bones and thickened to stabilize the solids. Not only the cutting guides for the fibula and maxilla but also the location arrangement of the transferred bone segments is defined by thickening the superficial faces. The CAD design is recorded as .stl files and three-dimensionally (3-D) printed as actual surgical guides. To check the accuracy of the guides, model surgery using 3-D-printed facial and fibular models is performed. These methods may be used to assist surgeons where commercial guides are not available.

Introduction

The use of CAD/CAM techniques has recently increased in dental and denture work. Following this evolution of CAD/CAM, osteocutaneous flap transfers using CAD/CAM are now used in the field of mandibular reconstruction after an oncologic wide resection of malignant tumors^1,2,3. Several companies in Western countries have begun to supply and sell a CAD/CAM cutting guide for the mandible region. A CAD/CAM reconstruction of the mandible is considered to have an advantage in terms of accuracy^4,5,

Protocol

This study was approved by the authors' institutional review board, and written consent forms were completed by all patients.

1. Preparation of Materials

1. Use a personal computer, computed tomographic (CT) data of facial bone and fibula, conversion software such as InVesalius²⁰, and three-dimensional (3-D) CAD software (e.g., Blender²¹).
   NOTE: A maximum thickness of 1 mm slices of CT data is recommended for an accurate design. For the actual surgical simulation, use the patient's CT data. For research, use free human 3-D data²².
....

Results

Using the procedure presented here, the resection area was determined first. Using CAD software, the resection area was completely circumscribed by the faces. This area was subtracted from the facial bone by a Boolean operation. The fibula image was placed on the defect, and fibular cutting faces were placed in the appropriate reconstructed points. All fibular cutting faces were linked to the fibula in a parent setting. These faces were made smaller and were united to make solids. The fib.......

Discussion

CAD/CAM reconstruction is considered to contribute to the attainment of an accurate osteotomy length, width, and angle in cutting bones while using cutting guides^{4,5,6,7,8,9,10,11,12,13}

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Information Technology Center, Renato Archer, Campinas, Brazil	InVesalius	Free software https://www.cti.gov.br/en/invesalius
The Blender Foundation, Amsterdam, Netherlands	Blender	Free software https://www.blender.org/
TurboSquid, Inc. 935 Gravier St., Suite 1600, New Orleans, LA.	Free 3D skeletal data file	Free3D https://free3d.com/3d-models/human
MakerBot Industries, LLC One MetroTech Center, 21st Fl, Brooklyn, NY.	MakerBot Replicator+	https://www.makerbot.com/replicator/
YouTube (Google, Inc.), 901 Cherry Ave. San Bruno, CA	video sharing website.	https://www.youtube.com/results?search_query=invesalius+dicom+to+stl
Artec 3D, 2, rue Jean Engling, Luxembourg	Artec Eva Lite	https://www.artec3d.com/portable-3d-scanners/artec-eva-lite
CloudCompare	CloudCompare	http://www.danielgm.net/cc/