• Journal of the Korean Arthroscopy Society
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• v.4 no.2
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• pp.159-165
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• 2000

Purpose : Endoscopic carpal tunnel release technique was developed and has being used to decrease postoperative morbidity and complications. The purpose of this study was to evaluate the clinical results and clinical usefulness of endoscopic carpal tunnel release using single portal technique. Methods and Materials : 18 carpal tunnel syndrome patients who were diagnosed by means of clinical symptoms, physical examination, and electrodiagnostic study had endoscopic carpal tunnel release using single portal technique with about 1 cm oblique wrist incision on 30 hands. And then they were followed-up and reviewed in the same way. Late results of operation were analysed by grading system according to patient's own assessments of relief of symptoms at the final fellow-up. The follow-up period ranged 6 to 13 months from surgery. Results : There were postoperative improvements with respect to clinical symptoms, physical examination, and electrodiagnostic study. 23 of 30 hands$(76.7\%)$ had complete resolution of symptoms. 27 hands$(90\%)$ were able to return to normal activities and work within 6 weeks, and 30 hands$(100\%)$ returned within 8 weeks. In grip strength study, 29 hands$(96.6\%)$ regained preoperative strength in 6 months. 12 of 22 hands$(55\%)$ had improvement with respect to thenar atrophy within 6 months. Late results were as follows . 23 hands$(76.7\%)$ was graded as excellent, 6 hands$(20\%)$ graded as good and 1 hand$(3.3\%)$ graded as fair, and there was no poor result. Conclusion : We think that endoscopic carpal tunnel release with single portal technique is technically safe and simple, if the surgeon takes step to stay within the safety zone based on local anatomy and selects an appropriate patient and that endoscopic carpal tunnel release does have advantages over open release. We agree that the surgeon must be prepared to perform an open technique, if technical difficulties arise, difficulty in introducing the device into the carpal tunnel is encountered, or the transverse fibers of the transverse carpal ligaments are not clearly seen.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.845-862
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• 2009

Recently, Tunnel in soil has been designed frequently because Mountain Tunnel has been increased rapidly due to straight of horizontal curve and residents' complaints, tunnel portal has been planned at closed to surface for minimization of environmental damage. To excavate tunnel in soil, where displacement and crushing occur in tunnel face and crown because of unstable ground condition, appropriate reinforcement method needed. On this paper, through design and construction of the soil tunnel, consider application of reinforcement method, economical efficiency and stability.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.10a
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• pp.139-146
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• 1999

Geological and geotechnical surveys, in general, should precede the excavation to ensure the stability of the tunnel md should be followed up according to the various geological condition during the excavation. However actually the standard support patterns which were decided during the design phases used be insisted for the whole excavation phases in spite of the various geological conditions. When $\bigcirc$$\bigcirc$ tunnel was excavated up to 25m long, the severe displacement was generated in the Portal area of $\bigcirc$$\bigcirc$ tunnel and the tunnel face was pally collapsed. Therefore, this paper present the case study on construction associated with the Umbrella Arch Method used in silty ground by the NATM.

• Journal of the Korean Society of Safety
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• v.25 no.3
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• pp.66-70
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• 2010

This paper analyzes difference between current tunnel ventilation calculation method and advanced one which considers effects of polluted air recirculation near tunnel portals. For the calculation, CFD(Computational fluid dynamics) technique was utilized. From the result, it was found that 4.38% more fresh air is required when there is polluted air recirculation near tunnel portal areas. Hence, it is recommanded that the consideration of polluted air recirculation should be made when deciding the ventilation requirements for tunnel.

• Proceedings of the KSME Conference
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• 2000.04b
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• pp.611-618
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• 2000

The test facility of the 1/60-scale models for the train-tunnel interactions was recently developed to investigate the effects of entry portal shapes, hood shapes and air-shafts for reducing the micro-pressure waves radiating to the surroundings of the tunnel exits by KRRI in Korea. The launching system of train model was chosen as air-gun type. In present test rig, after train model is launched, the blast wave by the driver did not enter to inside of the tunnel model. The train model is guided on the one-wire system from air-gun driver to the brake parts of test facility end. Some cases of the experiments were compared with numerical simulations to prove the test facility.

• Journal of the Korean Arthroscopy Society
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• v.12 no.1
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• pp.45-52
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• 2008

Purpose: The purpose of the study is to provide the clinical results of arthroscopic posterior cruciate ligament(PCL) reconstruction with preservation of the original PCL using transtibial tunnel and posterior transseptal portal. Materials and Methods: 36 patients underwent PCL reconstruction with achilles tendon allografts. We tried to preserve of the original PCL.At the final follow-up, patients were evaluated retrospectively by four measurements: Lysholm knee scores, IKDC grades, Telos stress radiography, and second look arthroscopy.Follow-up periods were from 12 months to 30 months. Results: The average Lysholm knee score improved from $66.0{\pm}8.67$ to $87.9{\pm}5.04$. Preoperative IKDC grades were abnormal in 15(41.7%) and severely abnormal in 21(58.3%), postoperative IKDC grades were normal in 6(16%),nearly normal in 24(66%), abnormal in 5(16%) and severely abnormal in 1(2%).The average side to side difference in Telos stress test decreased from $12.5{\pm}2.61(7{\sim}20)$ mm to $3.9{\pm}1.34(7{\sim}1)$ mm (paired sample T test, p=0.001) Conclusion: Arthroscopic posterior cruciate ligament(PCL) reconstruction with preservation of the original PCL using transtibial tunnel and posterior transseptal portal is useful surgical method.

• Journal of Korean Tunnelling and Underground Space Association
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• v.15 no.4
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• pp.387-400
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• 2013

In this study, the slope stability analysis and the landslide hazard assessment in tunnel portal slope were carried out. First, we selected highly vulnerable areas to slope failure using the slope stability analysis and analyzed the slope failure scale. According to analyses results, high vulnerable area to slope failure is located at 485~495 m above sea level. The slope is stable in a dry condition, while it becomes unstable in rainfall condition. The analysis results of slope failure scale show that the depth of slope failure is maximum 2.1 m and the length of slope failure is 18.6 m toward the dip direction of slope. Second, we developed a 3-D simulation program to analyze characteristics of runout behavior of debris flow. The developed program was applied to highly vulnerable areas to slope failure. The result of 3-D simulation shows that debris flow moves toward the central part of the valley with the movement direction of landslide from the upper part to the lower part of the slope. 3-D simulation shows that debris flow moves down to the bottom of mountain slope with a speed of 7.74 m/s and may make damage to the tunnel portal directly after 10 seconds from slope failure.

• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.427-432
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• 1999

When a high-speed train enters a tunnel, a compression wave is generated. This wave subsequently emerges from the exit portal of the tunnel, which causes an impulsive noise called 'Sonic boom' or 'micro-pressure wave'. In the present study, new method is presented for prediction of sonic boom noise, especially focusing on the effect of the nose shape of the train on the resultant noise. Acoustic theory for monopole source is used to represent a nose shape of the train in wave equation. Compression wave propagation in tunnel considering tunnel track condition and emission of sonic boom was calculated. The predicted compression waves and impulsive sound waves are compared with recent measurements, and show reasonable agreements.

• Journal of Korean Neurosurgical Society
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• v.62 no.1
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• pp.90-95
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• 2019

Objective : Anomalous muscles of the wrist are infrequently encountered during carpal tunnel surgery. Anatomic variants of the palmaris longus (PL), flexor digitorum superficialis, lumbricalis and abductor digiti minimi (ADM) have been reported but are usually clinically insignificant. Anomalies of the wrist muscles, encountered during endoscopic carpal tunnel surgery have rarely been described. I conducted this study to evaluate muscular anomalies of the volar aspect of the wrist, encountered during endoscopic carpal tunnel surgery. Methods : I studied a consecutive series of 1235 hands in 809 patients with carpal tunnel syndrome who underwent single-portal endoscopic carpal tunnel release (ECTR) from 2002 to 2014. Nine hundred seventy-three hands in 644 patients who had minimal 6-month postoperative follow-up were included in the study. The postoperative surgical outcome was assessed at least 6 months after surgery. Results : In eight patients, anomalous muscles were found under the antebrachial fascia at the proximal wrist crease and superficial to the ulnar bursa, passing superficial to the transverse carpal ligament. Those anomalous muscles were presumed to be variants of the PL or accessory ADM muscle, necessitating splitting and retraction to enter the carpal tunnel during the ECTR procedure. Other muscle anomalies were not seen within the carpal tunnel on the endoscopic view. The surgical outcome for all eight wrists was successful at the 6-month postoperative follow-up. Conclusion : Carpal tunnel surgeons, especially those using an endoscope should be familiar with unusual findings of anomalous muscles of the wrist because early recognition of those muscles can contribute to avoiding unnecessary surgical exploration and unsuccessful surgical outcomes.

• Tunnel and Underground Space
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• v.7 no.3
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• pp.191-201
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• 1997

Geological and geotechnical surveys, in general, should precede the excavation to ensure the safety of the tunnel and should be followed up according to the various geological condition during the excavation. However actually the standard support patterns which were decided during the design step used be insisted for the whole excavation steps in spite of the various geological conditions. OO tunnel was excavated with NATM and a support pattern type-V in weak rocks. When the tunnel was excavated up to 25m long, the severe displacement was generated in the portal area and the shotcrete was damaged to make the cracks and the tunnel face was totally collapsed. It might happen owing to the one-day heavy rain, but the exact reason for that accident should be found out and the new optimal support patternt needed. Consequently three dimensional numerical analysis was applied for the evaluation of the cause of the tunnel collapse instead of two dimensional analysis, because three dimensional analysis can show better the real field phenomenon than two dimensional analysis in which the load distribution methods are adopted for the tunnel excavation. We could simulate the actual situations with three dimensional finite difference code and propose the new optimal support patterns.