• Journal of Korean Neurosurgical Society
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• v.58 no.1
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• pp.9-13
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• 2015

Objective : To improve pedicle screw placement accuracy with minimal radiation and low cost, we developed specially designed K-wire with a marker. To evaluate the accuracy of thoracolumbar pedicle screws placed using the novel guide-pin and portable X-rays. Methods : Observational cohort study with computerized tomography (CT) analysis of in vivo and in vitro pedicle screw placement. Postoperative CT scans of 183 titanium pedicle screws (85 lumbar and 98 thoracic from T1 to L5) placed into 2 cadavers and 18 patients were assessed. A specially designed guide-pin with a marker was inserted into the pedicle to identify the correct starting point (2 mm lateral to the center of the pedicle) and aiming point (center of the pedicle isthmus) in posteroanterior and lateral X-rays. After radiographically confirming the exact starting and aiming points desired, a gearshift was inserted into the pedicle from the starting point into the vertebral body through the center of pedicle isthmus. Results : Ninety-nine percent (181/183) of screws were contained within the pedicle (total 183 pedicle screws : 98 thoracic pedicle screws and 85 lumbar screws). Only two of 183 (1.0%) thoracic pedicle screws demonstrated breach (1 lateral in a patient and 1 medial in a cadaver specimen). None of the pedicle breaches were associated with neurologic or other clinical sequelae. Conclusion : A simple, specially designed guide-pin with portable X-rays can provide correct starting and aiming points and allows for accurate pedicle screw placement without preoperative CT scan and intraoperative fluoroscopic assistance.

• Journal of the Korean Arthroscopy Society
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• v.10 no.2
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• pp.209-213
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• 2006

Purpose: Conventional transtibial approach for the anterior cruciate ligament (ACL) reconstruction tended to place the femoral tunnel in too vertical position (11 or 1 o'clock), which could provide the postoperative anteroposterior (AP) stability but not provided the rotational stability. Therefore we present a surgical technique to make the transtibial femoral tunnel at 10 or 2 o'clock position. Surgical approach: To make a transtibial femoral tunnel at the 10 or 2 o'clock position, the direction and position of the tibial drill guide was important. We set the tibial drill guide at $40{\sim}45$ degrees and the intraarticular guide tip was 1 mm anterior and medial to the conventional site. The starting point for the guide pin on the proximal tibia was proximal to the pes anserinus and anterior to the medial collateral ligament. The tibial tunnel was initially drilled 1mm less than the diameter of the graft. Then femoral offset guide could be easily placed at 10 or 2 o'clock position through the tibial tunnel. The tibial tunnel and the femoral tunnel of 30 mm in length were made with the reamer that was same size with the graft. Conclusion: We report a surgical technique to create a transtibial femoral tunnel at 10 or 2 o'clock position in ACL reconstruction to provide the rotational stability as well as the AP stability.

• Journal of International Society for Simulation Surgery
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• v.3 no.2
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• pp.87-89
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• 2016

Le fort 1 osteotomy surgery is one of the most popular surgical methods for the treatment of patients with facial bone deformities. An intermediate wafer splint is used to fix the bone segment to the planned position, but there are many steps that can cause errors. To reduce these errors, we propose a method of using a surgical guide made with virtual surgical simulation.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.42 no.2
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• pp.127-130
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• 2016

This clinical note introduces a method to assist surgeons in performing single-tooth dento-osseous osteotomy. For use in this method, a surgical guide was manufactured using computer-aided design/computer-aided manufacturing technology and was based on preoperative surgical simulation data. This method was highly conducive to successful single-tooth dento-osseous segmental osteotomy.

• Journal of Dental Rehabilitation and Applied Science
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• v.31 no.1
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• pp.67-74
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• 2015

Computer-guided surgery utilizing computed tomography is advantageous in placing implants precisely and conveniently. The purpose of the cases was to report a newly developed CT-based guide fabrication program and subtractive manufacturing using resin block. The guided surgery with the program and subtractive manufacturing allows not only precise translation of the treatment plan, but also offers additional significant benefits.

• The Journal of Korea Robotics Society
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• v.17 no.1
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• pp.8-15
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• 2022

In this paper, we proposed the method of virtual reality-based surgical navigation to reproduce the pre-planned position and angle of the pedicle screw in spinal fusion surgery. The goal of the proposed method is to quantitatively save the surgical plan by applying a virtual guide coordinate system and reproduce it in the surgical process through virtual reality. In the surgical planning step, the insertion position and angle of the pedicle screw are planned and stored based on the virtual guide coordinate system. To implement the virtual reality-based surgical navigation, a vision tracking system is applied to set the patient coordinate system and paired point-based patient-to-image registration is performed. In the surgical navigation step, the surgical plan is reproduced by quantitatively visualizing the pre-planned insertion position and angle of the pedicle screw using a virtual guide coordinate system. We conducted phantom experiment to verify the error between the surgical plan and the surgical navigation, the experimental result showed that target registration error was average 1.47 ± 0.64 mm when using the proposed method. We believe that our method can be used to accurately reproduce a pre-established surgical plan in spinal fusion surgery.

• The Journal of Korean Academy of Prosthodontics
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• v.57 no.2
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• pp.150-159
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• 2019

Nowadays, dental implant is one of the widely used treatment options for edentulous patients. Recently, a method of improving the accuracy of implant surgery using an implant surgical guide has been introduced and widely used in order to accurately place the implant in a proper position. Full-guided and half-guided implant surgery can be distinguished according to the level of surgical guide application during the implant surgery. It is true that full-guided implant surgery exhibits higher accuracy, but half- guided implant surgery is often performed in a clinical situation due to the factors such as the circumstances of the operation. A partially edentulous patient who lost teeth due to tooth fracture and periodontal disease was treated using implant and fixed prosthesis. Half-guided implant surgery was performed using an implant surgical guide during implant surgery, the accuracy of implant placement was analyzed.

• The Journal of Korea Robotics Society
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• v.15 no.4
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• pp.316-322
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• 2020

Endoscopic spine surgery is an advanced surgical technique for spinal surgery since it minimizes skin incision, muscle damage, and blood loss compared to open surgery. It requires, however, accurate positioning of an endoscope to avoid spinal nerves and to locate the endoscope near the target disk. Before the insertion of the endoscope, a guide needle is inserted to guide it. Also, the result of the surgery highly depends on the surgeons' experience and the patients' CT or MRI images. Thus, for the training, a number of haptic simulators for spinal needle insertion have been developed. But, still, it is difficult to be used in the medical field practically because previous studies require manual segmentation of vertebrae from CT images, and interaction force between the needle and soft tissue has not been considered carefully. This paper proposes AI-based automatic vertebrae CT-image segmentation and haptic rendering method using the proposed need-tissue interaction model. For the segmentation, U-net structure was implemented and the accuracy was 93% in pixel and 88% in IoU. The needle-tissue interaction model including puncture force and friction force was implemented for haptic rendering in the proposed spinal needle insertion simulator.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.32 no.2
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• pp.54-68
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• 2023

Treatment planning of edentulous patient with digital method is materialized by designing the surgical guide. When designing the surgical guide, we first implement the shape of the final prosthesis in the virtual space and then materialize the implantation plan based on this. However, it is challenging to make surgical guides for edentulous patients as their lack of both the reference for the arrangement of teeth and interocclusal relationship makes it hard to envision the shape of the final prosthesis. If there exists good partial or complete dentures or residual teeth, its teeth arrangement can be used as a reference for the virtual final prosthesis and the subsequent surgical guide. If such a reference is absent or unsatisfactory, a process of manufacturing a complete denture for diagnostic purposes and verifying it on patient's mouth is necessary and use it as a new reference for the virtual final prosthesis. But even if a surgical guide is produced through the reference from the thorough reflection of the virtual final prosthesis, when we use it in the surgical field, the intraoral condition of the patient may make the implants deviated from planned in the surgical guide. In the worst case, if the positioning of the surgical guide on the mouth is incorrect, it can lead to a catastrophic error that displaces all the implant, in which case the guided surgery would be much worse than the non-guided one. In this article, we will discuss how to obtain references of tooth arrangements in a timely manner and align or register them into a unified coordinate system in digital space, and also introduce how to transfer such an implantation plan from the virtual world into the patient's mouth of real world with minimum error. And lastly, I would like to express my opinion on the establishment of a rational and systematic protocol of guided surgery of the edentulous patients.

• Journal of International Society for Simulation Surgery
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• v.3 no.1
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• pp.33-35
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• 2016

Fibrous dysplasia(FD) is a disorder in which normal bone is replaced with pathologic tissue. When occurring in craniofacial regions, the zygomaticomaxillary complex is most commonly affected and this pathologic lesion results in facial asymmetry. and By using computer-assisted virtual simulation, precise maxillofacial contouring was achieved for harmonious facial morphology and the surgical procedure was simplified and the surgery brought satisfactory results in terms of both esthetics and functionality.