• Journal of Chest Surgery
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• v.54 no.6
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• pp.551-553
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• 2021

Although it is attractive, a limitation of aortic valve (AV) replacement (AVR) through a mini-thoracotomy approach (mini-AVR) is the limited exposure of the AV. Here, we present a simple exposure technique named "suspending commissural sutures" for a more efficient mini-AVR. The technique involves making 3 half-depth stitches with 1-0 silk at each of the commissures, which are anchored to each corresponding pericardial surface. These stitches are tightened up so that the aortic root is axially expanded and is pulled upward. The technique of suspending commissural stitches seems to offer reasonable exposure of the AV in mini-AVR, and shows excellent early surgical outcomes.

• Journal of Chest Surgery
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• v.54 no.6
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• pp.554-557
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• 2021

Surgeons are increasingly using the right mini-thoracotomy approach to perform aortic valve surgery. This approach has shown better results in terms of blood loss and length of hospital stay than the sternotomy approach. For selected patients requiring aortic root and ascending aorta surgery, a right mini-thoracotomy approach may prove beneficial. In our technique, we placed a 5-cm horizontal skin incision in the right second intercostal space. Femoro-femoral cardiopulmonary bypass was established. A valved aortic conduit was used for aortic root replacement. The patient's postoperative course was uneventful, with a short hospital stay. This technique offers a minimally invasive approach to aortic root and ascending aorta surgery with easy adaptability and reduced costs.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.10
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• pp.918-922
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• 2000

A lab-use home made control valve was made of easily obtainable materials and its performance was examined through a fluid flow experiment. By modifying the hole of a commercial valve a linearly adjustable valve for the flow control is made. The detail of valve assembling and modification is explained for the researchers who intend to employ a similar control valve.

• Journal of Yeungnam Medical Science
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• v.41 no.2
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• pp.96-102
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• 2024

Background: The aim of this study was to compare the early outcomes of octogenarians undergoing minimally invasive right anterior mini-thoracotomy aortic valve replacement (RAT-AVR) with those undergoing transcatheter aortic valve implantation (TAVI) for aortic valve disease. Methods: In this single-center retrospective study, data were collected from octogenarians before and after RAT-AVR and TAVI between January 2021 and July 2022. Short-term outcomes, including the length of hospital stay, in-hospital mortality, all-cause mortality, and other major postoperative complications, were compared and analyzed. Results: There were no significant differences in in-hospital mortality, stroke, acute kidney dysfunction requiring renal replacement therapy, length of intensive care unit stay, or length of hospital stay. However, the TAVI group had a higher incidence of permanent pacemaker insertion (10% vs. 0%, p=0.54) and paravalvular leaks (75% vs. 0%, p<0.001). Conclusion: In the present study on octogenarians, both TAVI and RAT-AVR showed comparable short-term results. Although both procedures were considered safe and effective in the selected group, RAT-AVR had a lower incidence of complete atrioventricular block and paravalvular regurgitation.

• Journal of Chest Surgery
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• v.32 no.4
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• pp.373-378
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• 1999

Background: Minimally invasive technique for various cardiac surgeries has become widely accepted since it has been proven to have distinct advantages for the patients. We describe here the results of our experiences of minimal incision in cardiac surgery. Material and Method: From February 1997 to November 1998, we successfully performed 31 cases of minimally invasive cardiac surgery. Male and female ratio was 17:14, and the patients age ranged from 1 to 75 years. A left parasternal incision was used in 9 patients with single vessel coronary heart disease. A direct coronary bypass grafting was done under the condition of the beating heart without cardiopulmonary bypass support(MIDCAB). Among these, one was a case of a reoperation 1 week after the first operation due to a kinked mammary artery graft. A right parasternal incision was used in one case of a redo mitral valve replacement. Mini-sternotomy was used in the remaining 21 patients. The procedures were mitral valve replacement and tricuspid annuloplasty in 6 patients, mitral valve replacement 5, double valve replacement 2, aortic valve replacement 1, removal of left atrial myxoma 1, closure of atrial septal defect 2, repair of ventricular septal defect 2, and primary closure of r ght ventricular stab wound 1. The initial 5 cases underwent a T-shaped mini-sternotomy, however, we adopted an arrow-shaped ministernotomy in the remaining cases because it provided better exposure of the aortic root and stability of the sternum after a sternal wiring. Result: The operation time, the cardiopulmonary bypass time, the aorta cross-clamping time, the mechanical ventilation time, the amount of chest tube drainage until POD#1, the chest tube indwelling time, and the duration of intensive care unit staying were in an acceptable range. There were two surgical mortalities. One was due to a rupture of the aorta cannulation site after double valve replacement on POD#1 in the mini-sternotomy case, and the other was due to a sudden ventricular arrhythmia after MIDCAB on POD#2 in the parasternal incision case. Postoperative complications were observed in 2 cases in which a cerebral embolism developed on POD#2 after a mini-sternotomy in mitral valve replacement and wound hematoma developed after a right parasternal incision in a single coronary bypass grafting. Neither mortality nor complication was directly related to the incision technique itself. Conclusion: Minimally invasive surgery using parasternal or mini-sternotomy incision can be used in cardiac surgeries since it is as safe as the standard full sternotomy incisions.

• Journal of Chest Surgery
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• v.21 no.3
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• pp.479-487
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• 1988

Valve replacements in 82 children, aging up to 15 years[mean 11.67 years] were done at Seoul National University Hospital during 13 years period from 1974 to 1986. The patients were composed of 5] males and 31 females and 50 patients had acquired heart disease and 32 patients congenital heart disease. 75 patients received single valve replacements, 6 patients double valve replacements, 1 patient triple valve replacement, and among all of them, 11 patients redo-replacements. The bioprosthetic valves have been applied to 58 patients and prosthetic valve to 24 patients and the latter was the main artificial valve since 1984. Among the 69 patients who had definite post-operative records, the overall mortality was 27.5%[20.3% was early mortality and 7.2% late mortality] and the overall mortality was lowered to 4.3% since 1984. There were early post-operative complication rate of 26.1% and late complication rate 34.8%, and among the latter, the valve failure rate was 11.4% patient-year, and the thrombo-embolism rate 1.76%/patient-year. 55 patients among the survivals after post-operative 1 month, were received follow-up with various anticoagulating medication for total 2046 patient-months[mini-mum 1 month to maximum 90 month, mean 37.2*25.44 months] and actuarial survival rate was 82*8% at 5 years and valve failure free and thrombo-embolic free survival rate were 61*8% and 90*3% respectively. And among them, valve failure free survival `rate of tissue valve were 91*6% at post-operative 2 years, 78*3% at 3 years, 59*9% at 4 years, 54*10% at 5 years, 53*15% at 6 years, so markedly decreased at 3-5 years post-operatively. These results suggest that cardiac valve replacement in children have been effective therapeutic method though various problems are still remained, and the choice of valve should be prosthetic valve mainly due to its durability at the present.

• Journal of Drive and Control
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• v.15 no.4
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• pp.81-90
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• 2018

Indoor construction site such as building demolition sites, tunnel, vinyl house, and cattle shed are subject to various risk factors such as falling stones, soot and bad odors. However, most of the mini excavators have no cabin that can protect the driver from such risk factors. Therefore, researches on remote control technology of construction equipment are actively conducted as a method for protecting the driver from the risk factors occurring in the working environment. For effective remote control, it is necessary to be able to control the travelling and work using a portable small transmitter. However, due to the limitation of the size of the transmitter, complex operation control is required to control two or more actuators with a single joystick. Also, it is essential to check how remote control characteristics change in various environments such as distance, signal strength, obstacle. Therefore, in this study, an algorithm that can control two actuators simultaneously with a single joystick signal was developed, and a communication method suitable for indoor and outdoor mini construction equipment by analyzing experimentally how the remote control characteristics vary according to various work environments and telecommunication methods proposed.

• Journal of Chest Surgery
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• v.56 no.1
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• pp.56-58
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• 2023

Untreated severe tricuspid regurgitation (TR) is associated with poor outcomes. Functional TR occurs secondary to dilatation of the annulus and tethering of the leaflets. Ring annuloplasty alone can correct most cases, but is insufficient in cases of severe annular dilatation due to severe leaflet tethering. In such cases, a tricuspid edge-to-edge technique may be an option. However, stitching of the leaflet tips alone is likely to result in tearing of the leaflets. Approximation of the durable chordae tendineae is considered helpful for this problem. Herein, we present the case of a 39-year-old man who had undergone open-heart surgery for acute type A aortic dissection 13 months earlier. A right mini-thoracotomy approach with a beating-heart strategy was used, which did not require unnecessary pericardial adhesiolysis and dissection. This technique had the advantage of reducing the operation time and the risk of bleeding. To summarize, we present a case of tricuspid valve repair in a high-risk patient with severe leaflet tethering that was successfully managed using these methods.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.04a
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• pp.435-440
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• 2000

In this study, we aims to develop the machining technology for the ultra precision surface and profile accuracy. For this purpose, we construct the electrolytic in process grinding system (ELID grinding) and apply to the cylindrical and internal grinding. Through the various machining experiments such as SCM steel., ceramics, tungsten carbide etc., we have obtained nanometer surface roughness. And we have applied this mirror grinding technique to hydraulic manual valve and mold core of mini disk optical pick-up base. For the development of fine mechanical part machining technology, e have made multi fiber optical connector using fine grinding technology. And constructed micro drilling system with process monitoring system which is possible to drill 50${\mu}{\textrm}{m}$ diameter hole.

• Journal of Chest Surgery
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• v.46 no.2
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• pp.93-97
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• 2013

Background: Minimally invasive cardiac surgery has emerged as an alternative to conventional open surgery. This report reviews our experience with atrial septal defect using the da VinciTM surgical robot system. Materials and Methods: This retrospective study included 50 consecutive patients who underwent atrial septal defect repair using the da VinciTM surgical robot system between October 2007 and May 2011. Among these, 13 patients (26%) were approached through a totally endoscopic approach and the others by mini-thoracotomy. Nineteen patients had concomitant procedures including tricuspid annuloplasty (n=10), mitral valvuloplasty (n=9), and maze procedure (n=4). The mean follow-up duration was $16.9{\pm}10.4$ months. Results: No remnant interatrial shunt was detected by intraoperative or postoperative echocardiography. The atrial septal defects were mainly repaired by Gore-Tex patch closure (80%). There was no operative mortality or serious surgical complications. The aortic cross clamping time and cardiopulmonary bypass time were $74.1{\pm}32.2$ and $157.6{\pm}49.7$ minutes, respectively. The postoperative hospital stay was $5.5{\pm}3.3$ days. Conclusion: The atrial septal defect repair with concomitant procedures like mitral valve repair or tricuspid valve repair using the da VinciTM system is a feasible method. In addition, in selected patients, complete port access can be helpful for better cosmetic results and less musculoskeletal injury.