• Maxillofacial Plastic and Reconstructive Surgery
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• v.37
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• pp.20.1-20.7
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• 2015

Background: The objectives of the present study were to investigate the reliability and outcomes of computer-assisted techniques in mandibular reconstruction with a fibula flap and verify whether the surgical navigation system was feasible in mandible reconstructive surgery. Methods: Eight cases were enrolled in the computer assisted surgery (CAS) group and 14 cases in the traditional group. The shaping and fixation of the fibula grafts were guided by computer assisted techniques, which could be monitored with the BrainLAB surgical navigation system. The variation of mandible configuration was evaluated by CT measurement in the Mimics software, including the variation of length, width, height and gonial angle of the mandible. The 3D facial soft tissue alteration was also analyzed in 3D chromatogram by Geomagic software. Results: All 22 fibula flaps survived. The mandibular configurations and facial contours had a better clinic result in the CAS group. The length, width, height and gonial angle of the reconstructive mandible were more similar to the original one. The Wilcoxon rank sum test analysis suggested significant differences in the measurements. The chromatographic analysis also visually showed superiority over the traditional group. Conclusions: The computer assisted surgical navigation method used in mandibular reconstruction is feasible and precise for clinical application. The contour of the reconstructed mandible and facial symmetry are improved with computer techniques.

• Journal of the Korean Orthopaedic Association
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• v.53 no.6
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• pp.478-489
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• 2018

Total knee arthroplasty has become a standard procedure for advanced knee arthritis to relieve pain and improve function. Computer-assisted navigation systems have been used in total knee arthroplasty to improve the mechanical axis of the limb as well as the alignment and position of the components. A computer-assisted navigation system has the advantage of real-time feedback during surgery, such as mediolateral balance in extension and flexion gap, alignment of the lower limb, and components. On the other hand, the computer-assisted navigation system requires an additional stab wound for tracker fixation, which can increase the likelihood of superficial wound infection and stress fractures and increase the operation time and cost of surgery. The clinical efficacy of computer-assisted navigation in total knee arthroplasty is also controversial. Compared to the conventional technique, computer navigation improves the accuracy of the postoperative mechanical axis within outliers of $3^{\circ}$ varus or $3^{\circ}$ valgus. This paper reviews the surgical technique, pitfalls, clinical and radiological outcomes, useful clinical cases, and future perspectives in computer-assisted navigation total knee arthroplasty.

• Journal of International Society for Simulation Surgery
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• v.2 no.2
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• pp.83-86
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• 2015

Recently, computer-assisted surgery is popular for performing well-planned operations. Computer-aided navigation system is helpful in maxillofacial surgery with real time instrument positioning and clear anatomic identification. Generally, segmental mandibulectomy and reconstruction flap surgery have done by extra-oral approach such as, submandibular approach. This case report describes performing intra-oral segmental mandibulectomy and reconstruction with monocortical deep circumflex iliac artery (DCIA) flap and CT guided implant surgery by using computer-aided surgical guide and navigation for managing ameloblastoma in a 31 years old female patient.

• The Journal of the Korean bone and joint tumor society
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• v.15 no.1
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• pp.1-6
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• 2009

The usefulness and accuracy of computer-assisted surgery have been evaluated clinically in many orthopedic fields, such as, joint replacement arthroplasty, cruciate ligament reconstruction, and pedicle screw placemen. Recently several preliminary reports have been issued on the application of navigation to bone tumor surgery. The main advantage of navigation-assisted bone tumor surgery is that it provides highly accurate three-dimensional radiological information for intraoperative guidance. In particular, distances from tumors to resection margins can be precisely determined using intraoperative three-dimensional images. Accordingly, the technique allows preservation of function to be maximized by minimizing unnecessary resection. However, surgeons should recognize that the accuracies of navigation systems in bone tumor surgery have some hidden pitfalls. Here, based on our clinical results, we describe the surgical techniques used and include some cautionary notes.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.8
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• pp.3270-3294
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• 2020

Some things come easily to humans, one of them is the ability to navigate around. This capability of navigation suffers significantly in case of partial or complete blindness, restricting life activity. Advances in the technological landscape have given way to new solutions aiding navigation for the visually impaired. In this paper, we analyze the existing works and identify the challenges of path selection, context awareness, obstacle detection/identification and integration of visual and nonvisual information associated with real-time assisted mobility. In the process, we explore machine learning approaches for robotic path planning, multi constrained optimal path computation and sensor based wearable assistive devices for the visually impaired. It is observed that the solution to problem is complex and computationally intensive and significant effort is required towards the development of richer and comfortable paths for safe and smooth navigation of visually impaired people. We cannot overlook to explore more effective strategies of acquiring surrounding information towards autonomous mobility.

• Journal of Biomedical Engineering Research
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• v.29 no.6
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• pp.451-456
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• 2008

Total knee arthroplasty(TKA) using computer-assisted navigation has been increased in order to improve the accuracy of femoral and tibial components implantation. Recently, a few clinical studies have reported on the femoral stress fracture after TKA using computer-assisted navigation. The purpose of this study is to investigate the stress concentration around the femoral pin-hole for different pin-hole diameter, the modes of pin penetration by finite element analysis to understand the effects of pin-hole parameters on femoral stress fracture risk. A three-dimensional finite element model of a male femur was reconstructed from 1 mm thick computed tomography(CT) images. The bone was rigidly fixed to a 25 mm above the distal end and 1500 N of axial compressive force and 12 Nm of axial torsion were applied at the femoral head. For all cases, transcortical pin penetration mode showed the highest stress fracture risk and unicortical pin penetration mode showed the lowest stress concentration. Pin-hole diameter increased the stress concentration, but pin number did not increase the stress dramatically. The results of this study provided a biomechanical guideline for pin-hole fracture risk of the computer navigated TKA.

• Journal of Korean Neurosurgical Society
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• v.56 no.1
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• pp.16-20
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• 2014

Objective : Two-dimensional fluoroscopy-based computerized navigation for the placement of pedicle screws offers the advantage of using stored patient-specific imaging data in providing real-time guidance during screw placement. The study aimed to describe the accuracy and reliability of a fluoroscopy-based navigation system for pedicle screw insertion. Methods : A total of 477 pedicle screws were inserted in the lower back of 96 consecutive patients between October 2007 and June 2012 using fluoroscopy-based computer-assisted surgery. The accuracy of screw placement was evaluated using a sophisticated computed tomography protocol. Results : Of the 477 pedicle screws, 461 (96.7%) were judged to be inserted correctly. Frank screw misplacement [16 screws (3.3%)] was observed in 15 patients. Of these, 8 were classified as minimally misplaced (${\leq}2mm$); 3, as moderately misplaced (2.1-4 mm); and 5, as severely misplaced (>4 mm). No complications, including nerve root injury, cerebrospinal fluid leakage, or internal organ injury, were observed in any of the patients. Conclusion : The accuracy of pedicle screw placement using a fluoroscopy-based computer navigation system was observed to be superior to that obtained with conventional techniques.

• Knee surgery & related research
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• v.30 no.4
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• pp.326-333
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• 2018

Purpose: To evaluate the reliability and validity of the femorotibial mechanical axis angle from radiographs in the weight bearing (WB) and supine positions compared with navigation-measured values. Materials and Methods: Sixty-eight cases of navigation-assisted total knee arthroplasty (TKA) were included. The pre- and postoperative whole leg radiographs (WLRs) in WB and supine positions were compared with the initial and final navigation values. Results: The mean mechanical axis angle from the preoperative WBWLR and navigation were not statistically different (p=0.079) and were correlated strongly with each other (intraclass correlation [ICC], 0.818). However, on postoperative measurements, although the WBWLR and navigation values were not different (p=0.098), they were not correlated with each other (ICC, 0.093). The standard error of measurement was $1.8^{\circ}{\pm}3.6^{\circ}$ for the preoperative WBWLR and $2.5^{\circ}{\pm}4.8^{\circ}$ for the postoperative WBWLR. The validity that was determined by the Bland-Altman plot was not acceptable for both pre- and postoperative measurements. Conclusions: The preoperative WBWLR could provide accurate but not precise measurement value of the femorotibial mechanical axis angle for navigation-assisted TKA, and postoperative measurements in navigation were not comparable with radiographic measurements. The lack of agreement was found between the radiographic and navigation measurements of the coronal alignment regardless of pre- or postoperative evaluation although the accuracy was found acceptable. Level of Evidence : Level 4.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2015.10a
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• pp.233-236
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• 2015

전 세계 해기교육기관에서 해사영어(Maritime English, ME)를 가르치고 있는 교원들이 모여 매년 개최하는 IMEC (International Maritime English Conference)을 소개하고, 2015년에 개최된 제27차 컨퍼런스의 프로그램을 우리 회원들에게 안내하고자 하며, IMEC 27에서 소개된 ChatBot를 가지고 참석한 회원들과 함께 진행하는 워크숍을 개최하고자 한다.

• Journal of Korean Neurosurgical Society
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• v.50 no.6
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• pp.523-527
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• 2011

A 67-year-old woman presented for evaluation of severe coccygeal pain. The computed tomography scans and magnetic resonance imaging showed an asymmetric midline sacral tumor invading the right lower portion of S2. To preserve both S2 nerve roots and to obtain negative surgical margins, a modified mid-sacrectomy with an aid of a computed navigation system was performed. The sacral tumor was excised en bloc with negative tumor margins. Both S2 nerve roots were preserved and additional reconstruction was not necessary because of minimal resection of the sacroiliac joint. We report a case of a sacral chordoma which was excised en bloc with adequate surgical margins by a computer-assisted modified mid-sacrectomy. The computed navigation system may be a useful tool for tumor targeting and safe osteotomies in sacral tumor surgery via the posterior only approach.