• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.45 no.5
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• pp.231-232
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• 2019

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1467-1470
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• 2008

An upper tibial opening wedge osteotomy is an operation to cure a malalignment and a degenerate arthritis. To prevent the postoperative malalignment caused by the upper tibial opening wedge osteotomy, the research to define the relationship between a Hinge Axis Angle and a Posterior Slope Angle is needed. The effect of the relationship between the hinge axis angle and the gap angle on the posterior slope angle is studied. After 3-D Compute Tomography (CT) scanning image is reconstructed, the virtual surgery is performed by the reconstructed 3-D tibia model. It was proved that the relationship between the hinge axis angle and the gap angle were constant and the simple mathematical model could be derived. To verify the suggested mathematical model, it compared with the measured data from the virtual surgery. In conclusion, while the deviation between the data from the virtual surgery and ones of the mathematical model under the gap angle<$10^{\circ}$ was less than 1%.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.36 no.4
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• pp.161-167
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• 2014

Purpose: The reconstruction of mandibular defects poses many difficulties due to the unique, complex shape of the mandible and the temporomandibular joints. With development of microvascular anastomosis, free tissue transplantation techniques, such as deep circumflex iliac artery (DCIA) flap and fibular free flap (FFF), were developed. The DCIA offers good quality and quantity of bone tissue for mandibular segmental defect and implant for dental rehabilitation. Virtual surgical planning (VSP) and stereolithography-guided osteotomy are currently successfully applied in three-dimensional mandibular reconstruction, but most use FFF. There are only a few articles on reconstruction with the DCIA that assess the postoperative results. Methods: Three patients admitted during a five month period (April of 2013 to August of 2013) underwent resection of mandible and DCIA musculo-osseous reconstruction using a VSP and stereolithographic modeling and assessment of outcomes included technical accuracy, esthetic contour, and functional outcomes. Results: This technique yielded iliac bone segment with excellent apposition and duplication of the preoperative plan. Flap survival was 100 percent and all patients maintained preoperative occlusion and contour. Conclusion: Based on our experience, we offer considerations and logically consistent protocols by classification of mandibular defects, and demonstrate the benefits in VSP and stereolithographic modeling of mandibular reconstructive surgery with DCIA flap.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.33 no.5
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• pp.413-419
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• 2011

Purpose: Reposition of the maxilla is a common technique for correction of midfacial deformities. To achieve the goal of the surgery, the maxilla should be repositioned based on the precisely planned position during surgery. The internal reference points (IRPs) and the external reference points (ERPs) are usually used to determine vertical dimension of maxilla, which is an important factor for confirming maxillary position. However, the IRPs are known to be inaccurate in determining the vertical dimension. In this study, we investigated the correlation of positional change of the modified IRPs with repositioned maxilla. Methods: The study group consisted of 26 patients with dentofacial deformities. For the simulation of the surgery, patient maxillary CT data and 3-D virtual surgery programs (V-$Works^{(R)}$ and V-$Surgery^{(R)}$) were used. IRPs of this study were set on both the lateral wall of piriform aperture, inferior margin of both infraorbital foramen, and the labial surfaces of the canine and first molar. The distance from the point on lateral wall of the piriform aperture to the point on the buccal surface of the canine was defined as IRP-C, and the distance from the point on the inferior margin of the infraorbital foramen to the point on the buccal surface of the $1^{st}$ molar was defined as IRP-M. After the virtual simulation of Le Fort I osteotomy, the changes in IRP-C and IRP-M were compared with the maxillary movement. All measures were analyzed statistically. Results: With respect to vertical movements, the IRP-C (approximately 98%) and the IRP-M (approximately 96%) represented the movement of the canine and the $1^{st}$ molar. Regarding rotating movement, the IRPs changed according to the movement of the canine and the $1^{st}$ molar. In particular, the IRP-C was changed in accordance with the canine. Conclusion: IRPs could be good indicators for predicting vertical movements of the maxilla during surgery.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.49 no.6
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• pp.365-368
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• 2023

The mentum plays an important role in the aesthetics of the face, and genioplasty is performed to improve an unbalance of the mentum. Among the various surgical approaches, setback genioplasty is used to create an aesthetic jaw-end appearance by moving the mentum backward when it protrudes more than normal. However, conventional setback genioplasty may be aesthetically disadvantageous because the profile of the mentum could become flat. This case study attempted to overcome the limitations of conventional setback genioplasty by rotating the position of the menton and pogonion. We devised a new method for setback genioplasty by rotating the segment anteroinferiorly. Using virtual surgery, we were able to specify the range of surgery more accurately and easily, and the surgery time was reduced. This case report showed the difference in chin soft tissue responses between conventional setback genioplasty and setback genioplasty with rotation.

• Annals of Hepato-Biliary-Pancreatic Surgery
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• v.26 no.3
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• pp.285-288
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• 2022

Three-dimensional (3D) modeling of the liver can be especially useful for both the surgeon and patient to understand the actual location of the tumor and planning the resection plane. Virtual reality (VR) can enhance the understanding of 3D structures and create an environment where the user can focus on contents provided. In the present study, a VR platform was developed using Unreal Engine 4 software (Epic Games, Potomac, MD, USA). Patient's liver based on magnetic resonance image was imported as a 3D model that could distinguish liver parenchyma, vascular structure, and cancer. Preoperative education videos for patients were developed. They could be viewed inside the VR platform. To evaluate the usefulness of VR education program for patients undergoing liver resection for hepatocellular carcinoma, a randomized clinical trial evaluating the knowledge and anxiety of the patient was designed. The case presented in this report was the first experience of performing the VR education program and examining the knowledge and anxiety using questionnaires. When the knowledge score increased, the anxiety score also increased after the education program. Based on findings of this pilot case study, the timing and place where the questionnaire will be answered can be modified for formal initiation of the randomized controlled study to examine the usefulness of VR in patient education.

• Archives of Plastic Surgery
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• v.41 no.5
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• pp.584-587
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• 2014

In the present study, a fibular osteotomy guide based on a computer simulation was applied to a patient who had undergone mandibular segmental ostectomy due to oncological complications. This patient was a 68-year-old woman who presented to our department with a biopsy-proven squamous cell carcinoma on her left gingival area. This lesion had destroyed the cortical bony structure, and the patient showed attenuation of her soft tissue along the inferior alveolar nerve, indicating perineural spread of the tumor. Prior to surgery, a three-dimensional computed tomography scan of the facial and fibular bones was performed. We then created a virtual computer simulation of the mandibular segmental defect through which we segmented the fibular to reconstruct the proper angulation in the original mandible. Approximately 2-cm segments were created on the basis of this simulation and applied to the virtually simulated mandibular segmental defect. Thus, we obtained a virtual model of the ideal mandibular reconstruction for this patient with a fibular free flap. We could then use this computer simulation for the subsequent surgery and minimize the bony gaps between the multiple fibular bony segments.

• Journal of Korea Multimedia Society
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• v.12 no.5
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• pp.737-744
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• 2009

This paper is to study and implement 3D Virtual Face Aesthetic Surgery System which provides more satisfaction by comparing the before-and-after plastic face surgery using 3D face model. For this study, we implemented 3D Face Model Generating System which resembles 2D image of the user based on 3D Korean standard face model and user's 2D pictures. The proposed 3D Virtual Face Aesthetic Surgery System in this paper consists of 3D Face Model Generating System, 3D Skin Texture Mapping System, and Detailed Adjustment System for reflecting the detailed description of face. The proposed system provides more satisfaction to the medical uses and stability in the surgery in compare with other existing systems.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.11
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• pp.83-90
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• 2004

In this paper we present a new real-time visual servoing unit for laparoscopic surgery This unit can automatically control laparoscope manipulator through visual tracking of laparoscopic surgical tool. For the tracking, we present two-stage adaptive CONDENSATION(conditional density propagation) algorithm to extract the accurate position of the surgical tool tip from a surgical image sequence in real-time. This algorithm can be adaptable to abrupt change of laparoscope illumination. For the control, we present virtual damper system to control a laparoscope manipulator safely and stably. This system causes the laparoscope to move under constraint of the virtual dampers which are linked to the four sides of image. The visual servoing unit operates the manipulator in real-time with locating the surgical tool in the center of image. The experimental results show that the proposed visual tracking algorithm is highly robust and the controlled manipulator can present stable view with safe.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.5 s.98
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• pp.112-123
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• 1999

Virtual reality is becoming a powerful tool for various applications such as training, entertainment, surgery, tele-robotics etc. One potential use for virtual reality is to allow several users to interact in a single virtual environment, for example several students sitting in front of different computers connected over a network. In this paper, we present a loosely coupled architecture of haptic display in the multi-user virtual world. The method of controlling haptic devices as well as the way of configuring individual haptic display system are addressed. We will develop an experimental virtual reality system for two remote users and conclude with an experimental work for the task of a multi-player ping-pong and grasping of a common object.