• Journal of the Korean Society for Precision Engineering
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• v.30 no.5
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• pp.520-528
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• 2013

A 20 mm diameter of small 5-D.O.F. force sensor has been developed for applications in MR-field Optical intensity modulation was adopted for transducing to miniaturize the sensor structure. For its accurate sensing of 5-D.O.F. force/moment, the elastic detecting module was designed to respond independently to each force or moment component. And for small size, two optical transducing modules of 2-D.O.F. and 3-D.O.F. were designed and integrated with the detecting module where optical fibers were arranged in parallel to make the sensor small. It is confirmed by calibration test that the detecting modules deforms linearly and independently to the input force. The results of evaluating test show that the range and resolution of forces are ${\pm}4$ N and 0.94~7.1 mN and the range and resolution of moments are ${\pm}120N{\cdot}mm$ and $0.023{\sim}0.034N{\cdot}mm$.

• Journal of Korean Foot and Ankle Society
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• v.25 no.4
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• pp.157-164
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• 2021

Purpose: This study aimed to report the current trends in the management of the hallux valgus (HV) deformity over the last few decades through a survey of the Korean Foot and Ankle Society (KFAS) members. Materials and Methods: A web-based questionnaire containing 34 questions was sent to all KFAS members in September 2021. The questions were mainly related to the preferred techniques and clinical experience in correction in patients with an HV deformity. Answers with a prevalence of ≥50% of respondents were considered a tendency. Results: One hundred and nine (19.8%) of the 550 members responded to the survey. The most common symptom for determining surgical treatment was bunion pain (68.8%), and different surgical techniques were selected according to the following radiological parameters: HV angle 30 to 40 degrees and intermetatarsal angle 15 to 20 degrees. The two procedures most preferred by the respondents were distal chevron osteotomy (55.0%), and proximal chevron osteotomy (21.1%). In an average of 71.6% of respondents, Arkin osteotomy was performed simultaneously during HV surgery. HV accompanied by an overriding deformity of the second toe was most often addressed with a combination of second metatarsal osteotomy and soft tissue rebalancing procedure (35.8%). After HV surgery, the recurrence rate of HV deformity was found to be 12.2% on average and the surgeons who had performed minimally invasive surgery (MIS) for HV comprised 34.9% of the total respondents. Conclusion: This study provides updated information on the current trends in the management of the HV deformity in Korea. Both consensus and variation in the approach to patients with HV were identified by this survey study. Although MIS for HV has increased, it appears the consensus for selecting this method has not yet been established.

• Journal of Korean Neurosurgical Society
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• v.67 no.3
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• pp.354-363
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• 2024

Objective : This study aims to determine the optimal dose of recombinant-human bone morphogenic protein-2 (rhBMP-2) for successful bone fusion in minimally invasive lateral lumbar interbody fusion (MIS LLIF). Previous studies show that rhBMP is an effective alternative to autologous iliac crest bone graft, but the optimal dose remains uncertain. The study analyzes the fusion rates associated with different rhBMP doses to provide a recommendation for the optimal dose in MIS LLIF. Methods : Ninety-three patients underwent MIS LLIF using demineralized bone matrix (DBM) or a mixture of rhBMP-2 and DBM as fusion material. The group was divided into the following three groups according to the rhBMP-2 usage : group A, only DBM was used (n=27); group B, 1 mg of rhBMP-2 per 5 mL of DBM paste (n=41); and group C, 2 mg of rhBMP-2 per 5 mL of DBM paste (n=25). Demographic data, clinical outcomes, postoperative complication and fusion were assessed. Results : At 12 months post-surgery, the overall fusion rate was 92.3% according to Bridwell fusion grading system. Groups B and C, who received rhBMP-2, had significantly higher fusion rates than group A, who received only DBM. However, there was no significant increase in fusion rate when the rhBMP-2 dosage was increased from group B to group C. The groups B and C showed significant improvement in back pain and Oswestry disability index compared to the group A. The incidence of screw loosening was decreased in groups B and C, but there was no significant difference in the occurrence of other complications. Conclusion : Usage of rhBMP-2 in LLIF surgery leads to early and increased final fusion rates, which can result in faster pain relief and return to daily activities for patients. The benefits of using rhBMP-2 were not significantly different between the groups that received 1 mg/5 mL and 2 mg/5 mL of rhBMP-2. Therefore, it is recommended to use 1 mg of rhBMP-2 with 5 mL of DBM, taking both economic and clinical aspects into consideration.

• Journal of the Korea Convergence Society
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• v.9 no.11
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• pp.291-297
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• 2018

Due to difficulty in minimally invasive surgery, training simulator is actively researched. A volumetric deformable organ is created by employing a shape-retaining chain-linked (S-chain) model to realize positioning a human organ model in virtual space. Since the main principle of the S-chain algorithm is that the repulsive force is proportional to the number of chain elements, the calculation time can be increased according to the magnitude of deformation. In this work, the advanced S-chain algorithm is used to calculate the repulsive torque according to spin motion. Finally, haptic architecture was constructed using this S-chain model by incorporating the virtual organ with a real master device, which allows the repulsive force and target position to be transferred to each other. The control performance of S-chain algorithm has been evaluated via experiment.