• Journal of Institute of Control, Robotics and Systems
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• v.19 no.12
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• pp.1160-1166
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• 2013

This paper presents feedforward controllers to improve the control performance of the motion and grasping force of a surgical instrument used in an MIS (Minimally Invasive Surgery) robot. The surgical instrument has a long distance between the drive motors and its active joints. Therefore, the gripper on the instrument is controlled by a cable drive mechanism, which generates a coupled motion between the wrist joint and the grip direction. In order to solve the problem, this paper analyzes the pulley composition of the surgical instrument and proposes feedforward controllers to eliminate the coupled motion. Furthermore, feedforward controllers to regulate the grasping force are proposed to deal with another coupling problem between the grasping force of the instrument and the motion of the instrument joints. The experimental results demonstrate the improved control performance of the motion and grasping force of the instrument.

• Journal of Chest Surgery
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• v.51 no.5
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• pp.363-366
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• 2018

One of the complications of permanent pacemaker implantation is unintended phrenic nerve stimulation. A 15-year-old boy with a permanent pacemaker presented with chest discomfort due to synchronous chest wall contraction with pacing beats. Even after reprogramming of the pacemaker, diaphragmatic stimulation persisted. Therefore, we performed thoracoscopic phrenic nerve insulation using a Gore-Tex patch to insulate the phrenic nerve from the wire. A minimally invasive approach using a thoracoscope is a feasible option for retractable phrenic nerve stimulation after pacemaker implantation.

• Journal of Minimally Invasive Surgery
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• v.21 no.4
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• pp.139-140
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• 2018

• Journal of Korean Neurosurgical Society
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• v.50 no.5
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• pp.441-445
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• 2011

Objective : There are technical limitations of multi-level posterior pedicle screw fixation performed by the percutaneous technique. The purpose of this study was to describe the surgical technique and outcome of minimally invasive multi-level posterior lumbar interbody fusion (PLIF) and to determine its efficacy. Methods : Forty-two patients who underwent mini-open PLIF using the percutaneous screw fixation system were studied. The mean age of the patients was 59.1 (range, 23 to 78 years). Two levels were involved in 32 cases and three levels in 10 cases. The clinical outcome was assessed using the visual analog scale (VAS) and Low Back Outcome Score (LBOS). Achievement of radiological fusion, intra-operative blood loss, the midline surgical scar and procedure related complications were also analyzed. Results : The mean follow-up period was 25.3 months. The mean LBOS prior to surgery was 34.5, which was improved to 49.1 at the final follow up. The mean pain score (VAS) prior to surgery was 7.5 and it was decreased to 2.9 at the last follow up. The mean estimated blood loss was 238 mL (140-350) for the two level procedures and 387 mL (278-458) for three levels. The midline surgical scar was 6.27 cm for two levels and 8.25 cm for three level procedures. Complications included two cases of asymptomatic medial penetration of the pedicle border. However, there were no signs of neurological deterioration or fusion failure. Conclusion : Multi-level, minimally invasive PLIF can be performed effectively using the percutaneous transpedicular screw fixation system. It can be an alternative to the traditional open procedures.

• Journal of Chest Surgery
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• v.36 no.2
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• pp.98-100
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• 2003

Recently, Minimally invasive direct coronary artery bypass surgery (MIDCAB) is becoming one of the rapidly developing strategies in cardiac surgery. We report a case of MIDCAB used in upper sternotomy because of severe pleural adhesion.

• Journal of Chest Surgery
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• v.49 no.1
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• pp.70-72
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• 2016

The single-suture neochorda-folding plasty technique is a modification of existing mitral valve repair techniques. In the authors' experience, its simplicity, reliability, and versatility make it a useful technique for mitral valve repair, especially when a minimally invasive approach is used.

• Journal of Chest Surgery
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• v.47 no.2
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• pp.106-110
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• 2014

Background: There are several modalities of coronary artery revascularization for multivessel coronary artery disease. Hybrid coronary revascularization (HCR) with minimally invasive direct coronary artery bypass grafting was introduced for high-risk patients, and recently, many centers have been using it. Limited incisional full sternotomy coronary artery bypass (LIFCAB) involves left internal thoracic artery (LITA)-to-left anterior descending coronary artery (LAD) anastomosis through a sternotomy with a minimal skin incision; it could be considered another technique for minimally invasive LITA-to-LAD anastomosis. Our center has performed HCR using LIFCAB, and in this paper, we report our short-term results, obtained in the past 3 years. Methods: The medical records of 38 patients from May 2010 to June 2013 were analyzed retrospectively. The observation period after HCR was 1 to 37 months (average, $18.3{\pm}10.3$ months). The patency of revascularization was confirmed with postoperative coronary angio-computerized tomography or coronary angiography. Results: There were 3 superficial wound complications, but no mortalities. All the LITA-to-LAD anastomoses were patent in the immediate postoperative and follow-up studies, but stenosis was detected in 3 cases of percutaneous coronary intervention. Conclusion: HCR using LIFCAB is safe and yields satisfactory results from the viewpoint of revascularization for multivessel disease.

• Journal of Chest Surgery
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• v.51 no.1
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• pp.8-14
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• 2018

Background: Minimally invasive direct coronary artery bypass grafting (MIDCAB) has the advantage of allowing arterial grafting on the left anterior descending artery without a sternotomy incision. We present our single-center clinical experience of 66 consecutive patients. Methods: All patients underwent MIDCAB through a left anterior small thoracotomy between August 2007 and July 2015. Preoperative, intraoperative, postoperative and follow-up data - including major adverse cardiovascular and cerebrovascular events (MACCE), graft patency, and the need for re-intervention - were collected. Results: The mean age of the patients was $69.4{\pm}11.1years$ and 73% were male. There was no conversion to an on-pump procedure or a sternotomy incision. The 30-day mortality rate was 1.5%. There were no cases of stroke, although 2 patients had to be re-explored for bleeding, and 81.8% were extubated in the operating room or on the day of surgery. The median stay in the intensive care u nit and in the hospital were 1.5 and 9.6 days, respectively. The median follow-up period was 11 months, with a 5-year overall survival rate of $85.3%{\pm}0.09%$ and a 5-year MACCE-free survival rate of $72.8%{\pm}0.1%$. Of the 66 patients, 32 patients with 36 grafts underwent a postoperative graft patency study with computed tomography angiography or coronary angiography, and 88.9% of the grafts were patent at $9.7{\pm}10.8months$ postoperatively. Conclusion: MIDCAB is a safe procedure with low postoperative morbidity and mortality and favorable mid-term MACCE-free survival.

• Journal of Digital Convergence
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• v.17 no.7
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• pp.265-274
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• 2019

The purpose of this study was to know the difference in pain, sleep, self-care behavior in patients performed by sternotomy and robotic minimally invasive cardiac surgeries. The participants were 64 patients with sternotomy and 64 patients with minimal thoracotomy in heart valve surgeries at a tertiary hospital in Seoul. Data were analyzed using descriptive statistics, ${\chi}^2$ test, paired t-test. with SPSS/WIN(22.0). The participants with minimally invasive thoracotomy felt severe pain than the patients with thoracotomy at post operation day 2 & 5. The severe pain site were the surgical site in both groups. The participants with sternotomy had better sleep than minimally invasive thoracotomy patients. Self-care behavior was higher in the minimally invasive thoracotomy group. Therefore, despite the many advantages of robotic surgery such as rapid recovery and shortening of length of stay in hospital, accurate pain assessment and application of differentiated protocols are needed for the management of pain in the patients with robotic minimally invasive cardiac surgeries. In addition, a structured education program intervention is needed to improve comfort by considering gender, age, and method of operation.

• Journal of Korean Neurosurgical Society
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• v.42 no.4
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• pp.293-299
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• 2007

Objective : Thoracoscopic spinal surgery provides minimally invasive approaches for effective vertebral decompression and reconstruction of the thoracic and thoracolumbar spine, while surgery related morbidity can be significantly lowered. This study analyzes clinical results of thoracoscopic spinal surgery performed at our institute. Methods : Twenty consecutive patients underwent video-assisted thoracosopic surgery (VATS) to treat various thoracic and thoracolumbar pathologies from April 2000 to July 2006. The lesions consisted of spinal trauma (13 cases), thoracic disc herniation (4 cases), tuberculous spondylitis (1 case), post-operative thoracolumbar kyphosis (1 case) and thoracic tumor (1 case). The level of operation included upper thoracic lesions (3 cases), midthoracic lesions (6 cases) and thoracolumbar lesions (11 cases). We classified the procedure into three groups: stand-alone thoracoscopic discectomy (3 cases), thoracoscopic fusion (11 cases) and video assisted mini-thoracotomy (6 cases). Results : Analysis on the Frankel performance scale in spinal trauma patients (13 cases), showed a total of 7 patients who had neurological impairment preoperatively : Grade D (2 cases), Grade C (2 cases), Grade B (1 case), and Grade A (2 cases). Four patients were neurologically improved postoperatively, two patients were improved from C to E, one improved from grade D to E and one improved from grade B to grade D. The preoperative Cobb's and kyphotic angle were measured in spinal trauma patients and were $18.9{\pm}4.4^{\circ}$ and $18.8{\pm}4.6^{\circ}$, respectively. Postoperatively, the angles showed statistically significant improvement, $15.1{\pm}3.7^{\circ}$ and $11.3{\pm}2.4^{\circ}$, respectively(P<0.001). Conclusion : Although VATS requires a steep learning curve, it is an effective and minimally invasive procedure which provides biomechanical stability in terms of anterior column decompression and reconstruction for anterior load bearing, and preservation of intercostal muscles and diaphragm.