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Dive into the research topics where Jong Hyun Pyun is active.

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Featured researches published by Jong Hyun Pyun.


Journal of Laparoendoscopic & Advanced Surgical Techniques | 2016

Robot-Assisted Radical Cystectomy with Total Intracorporeal Urinary Diversion: Comparative Analysis with Extracorporeal Urinary Diversion.

Jong Hyun Pyun; Hyung Keun Kim; Seok Cho; Sung Gu Kang; Jun Cheon; Jeong Gu Lee; Je Jong Kim; Seok Ho Kang

PURPOSE To compare the perioperative outcomes, postoperative complications, and early oncologic outcomes of intracorporeal urinary diversion (ICUD) with those of extracorporeal urinary diversion (ECUD) following robot-assisted radical cystectomy (RARC) performed by a single surgeon at a tertiary referral hospital. MATERIALS AND METHODS We reviewed a prospectively maintained, institutional review board-approved database of 70 patients treated with RARC and pelvic lymph node (LN) dissection for bladder cancer performed from 2007 through 2014. Data were collected for 64 patients who underwent either ICUD or ECUD. RESULTS Thirty-eight patients underwent ECUD, and the remaining 26 underwent ICUD. Urinary diversion was performed extracorporeally in the first 37 cases and performed intracorporeally thereafter. There were no significant differences in patient characteristics between the ECUD and ICUD groups. Mean total operative time was 468 minutes for ECUD and 581 minutes for ICUD (P < .05). Mean estimated blood loss was 265 and 148 mL, respectively (P < .05). Minor and total complication rates for patients with the ECUD were higher than in patients with the ICUD (minor: 47.4% vs. 15.4%; total: 57.9% vs. 30.8%; P < .05). All patients showed negative surgical margin, while 21% in the ECUD group and 26.9% in the ICUD group had pathologic stage T3 or T4 (P > .05). The mean LN yield was 23.2 and 31.8, respectively (P < .05). CONCLUSIONS From our experience, the results show that ICUD after RARC can be successful, with the benefits of decreased blood loss and lower transfusion and complication rates than ECUD. A larger series and long-term follow-up data will be necessary to support our results.


Korean Journal of Urology | 2015

Concurrent and predictive validation of robotic simulator Tube 3 module

Jae Yoon Kim; Seung Bin Kim; Jong Hyun Pyun; Hyung Keun Kim; Seok Cho; Jeong Gu Lee; Je Jong Kim; Jun Cheon; Seok Ho Kang; Sung Gu Kang

Purpose We previously described a new procedure specific module (Tube 3) to allow the practice of vesicourethral anastomosis after robot-assisted radical prostatectomy. Herein, we report a predetermined proficiency level of Tube 3 and preliminary validation to explore whether this new module can lead to performance improvement in the da Vinci system. Materials and Methods Eight urology residents and three urology fellows performed the Tube 3 module 1 hour daily for 7 days. The learning curve was depicted through a scatterplot and the stable point was identified through the cumulative sum chart. Concurrent and predictive validations were performed with the da Vinci system. The mean time to complete the task and end product rating score between Tube 3 training group and no Tube 3 training group were compared. Results Concerning the learning curve, about 41 repetitions comprising about 5 hours were needed to achieve this stable point when the mean time to complete Tube of 384 seconds was set as a target. With regarding to the concurrent and predictive validation, there significant differences were evident in the mean time to complete 16 needle passages and the vesicourethral anastomosis and the end product rating score. Conclusions The virtual reality (VR) simulator can yield sufficient improvement in technical performance in Tube 3 within 5 hours. The acquired proficiency can be transferable to the vesicourethral anastomosis using the da Vinci system.


Korean Journal of Urology | 2015

Standardized analysis of complications after robot-assisted radical cystectomy: Korea University Hospital experience

Jong Hyun Pyun; Hyung Keun Kim; Jae Yoon Kim; Seung Bin Kim; Seok Cho; Sung Gu Kang; Young Hwii Ko; Jun Cheon; Jeong Gu Lee; Je Jong Kim; Seok Ho Kang

Purpose To analyze the complications after robot-assisted radical cystectomy (RARC) by use of a standardized reporting methodology by a single surgeon. Materials and Methods We prospectively reviewed a maintained institutional database of 52 patients who underwent RARC to manage bladder cancer and were followed up in 3 months by a single surgeon at Korea University Medical Center from 2007 through 2014. All complications within 90 days of surgery were defined and categorized into 5 grades according to the Clavien-Dindo classification. Logistic regression analysis was used to identify predictors of complications. Results Fifty percent of patients (26 of 52) experienced a complication of any grade <90 days after surgery, and 11 patients (21.2%) experienced a major complication. Complications were grouped in systems-based categories. Fifty complications occurred in 52 patients and hematologic complication (transfusion) was the most common (13 of 52). Wound dehiscence, anastomotic leakage, urinary tract obstruction, mechanical obstruction, and thromboembolism occurred as major complications. Mean estimated blood loss (EBL) was 247 mL and mean total operative time was 496 minutes. The mean number of lymph nodes harvested was 24.6, with 30.5 for extended dissection. EBL (over 300 mL), operative time, and method of urinary diversion were significant negative predictors of minor complications, whereas EBL (over 300 mL) was a significant negative predictor of major complications (p<0.05). Conclusions The present results show that the complication rate reported by use of a standardized methodology after robotic radical cystectomy is still considerable although comparable to that of contemporary robot series. EBL, operative time, and diversion methods were predictors of complications.


Korean Journal of Urology | 2014

Tumor-Specific Immunity Induced by Cryoablation in a Murine Renal Cell Carcinoma Model

Hyung Keun Kim; Jong Hyun Pyun; Seok Cho; Sung Gu Kang; Jeong Gu Lee; Je Jong Kim; Jun Cheon; Hong Seok Park; Seok Ho Kang

Purpose To evaluate tumor-specific immunity and define the mechanisms involved in the cryoimmunologic response, we compared the tumor control efficacy and immunologic responses of cryoablation with those of surgical excision in a tumor rechallenge model. Materials and Methods Sixty BALB/c mice with RENCA tumors that were generated in the left flank area underwent cryoablation or radical excision. The mice successfully treated were rechallenged with RENCA or an undifferentiated colon carcinoma cell line, CT26, in the contralateral right flank area. The recurrence rate after tumor rechallenge in each group was then observed. To assess the immunologic response of each treatment modality, fluorescent-activated cell sorting (FACS) analysis and a cytotoxicity assay using 51Cr release were performed. Results After reinoculation of the RENCA cells, the rate of tumor growth was significantly higher in the surgical excision group than in the cryoablation group (94.4% vs. 11.1%, p=0.001). In the cryoablation group, the tumor growth rate was significantly increased after rechallenge of CT26 cells compared with RENCA (94.1% vs. 11.1%, p=0.001). The cryoablation group showed an elevated CD3, CD4, CD8 T, and natural killer cell count in the FACS analysis and also showed significantly increased cytotoxicity in the 51Cr release assay compared with the excision group. Conclusions These results showed that cryoablation, compared to surgical resection, was more effective in preventing tumor growth after rechallenge with RENCA cells and that this response was tumor-specific, because the CT26 cells did not have the same effect.


Korean Journal of Urology | 2015

Renal cryoablation of small renal masses: A Korea University experience

Hyung Keun Kim; Jong Hyun Pyun; Jae Yoon Kim; Seung Bin Kim; Seok Cho; Sung Gu Kang; Jeong Gu Lee; Je Jong Kim; Jun Cheon; Seok Ho Kang

Purpose To evaluate the perioperative, functional, and oncological outcomes of renal cryoablation (RC) of small renal masses (SRMs) performed in Korea University Hospital. Materials and Methods We reviewed an Institutional Review Board-approved database of 70 patients who underwent RC and were followed up for a minimum of 3 months by a single surgeon in Korea University Hospital from August 2007 to May 2014. Among these patients, 68 patients (79 renal masses) were enrolled in our research. We evaluated perioperative, functional, and oncologic outcomes of RC. Results A total of 68 patients (79 renal masses) underwent RC in our institution. The mean age of the patients was 62.0 years. The mean tumor size was 2.25 cm. Among the 59 patients who underwent laparoscopic surgery, only 1 patient (1.47%) was converted to open surgery. No other perioperative complications occurred. The mean preoperative and 1-month postoperative estimated glomerular filtration ratio (eGFR) were 71.8 and 68.3 mL/min/1.73 m2, respectively (p=0.19). The mean 1-year postoperative eGFR was 65.0 mL/min/1.73 m2 (p=0.25). The mean follow-up period was 59.76 months (range, 3-119 months). Local tumor recurrence occurred in eight tumors (15.4%; a total of 52 renal cell carcinomas). Concerning treatment in the patients with recurrence, five patients underwent re-treatment and three patients are under active surveillance. None of the eight patients who experienced local recurrence had additional recurrence or tumor progression during the follow-up period. In our study, the recurrence-free rate was 83.0% and the cancer-specific survival rate was 100%. Moreover, the 5- and 10-year overall survival rates were both 100%. Conclusions Long-term experience with RC in our institution demonstrates that RC is a safe and effective treatment for patients with SRMs.


Urologic Oncology-seminars and Original Investigations | 2017

A prospective, multicenter analysis of pseudocapsule characteristics: Do all stages of renal cell carcinoma have complete pseudocapsules?☆

Seok Cho; Jeong Hyeon Lee; Seung Hyun Jeon; Jinsung Park; Sang Hyub Lee; Chul Hwan Kim; Ji Youn Sung; Joo Heon Kim; Jong Hyun Pyun; Jeong Gu Lee; Je Jong Kim; Jun Cheon; Sung Gu Kang; Seok Ho Kang

OBJECTIVES To assess the characteristics of pseudocapsule (PC) in localized renal cell carcinoma (RCC) by analyzing the rates of completeness of PC and pseudocapsular invasion and clinical and pathological risk factors of it. MATERIALS AND METHODS Between February 2013 and September 2015, data were gathered prospectively from 180 consecutive patients who underwent partial nephrectomy or radical nephrectomy at 3 institutions, and 161 were enrolled. Evaluated factors included age and sex; histologic factors such as tumor diameter, stage, tumor subtype, necrosis, and Fuhrman grade; and clinical factors such as RENAL score; and completeness of PC. RESULTS Only 94 tumors (58.4%) were surrounded by a continuous PC completely, 62 (38.5%) were partially surrounded, and 5 (3.1%) had no PC. Overall, 56 PCs (34.8%) were free from invasion, 58 PCs (36.0%) had partial invasion of PC without parenchymal invasion, and 47 PCs (29.2%) had parenchymal invasion. Defining parenchymal invasion as true pseudocapsular invasion, histologic diameter, RCC subtype, and completeness of PC were significant predictors for parenchymal invasion on multivariate analysis (P = 0.006, 0.046, and 0.002, respectively). CONCLUSIONS Rate of complete PC in RCC is relatively low in this study. The risk factors for pseudocapsular invasion were a histologic diameter greater than 4cm, non-clear cell histology, and an incomplete PC. Surgeons must prepare for the possibility of a positive surgical margin if a tumor has at least one of these risk factors.


Kaohsiung Journal of Medical Sciences | 2017

Efficacy of holmium laser enucleation of the prostate (HoLEP) in men with bladder outlet obstruction (BOO) and non-neurogenic bladder dysfunction

Jong Hyun Pyun; Sung Gu Kang; Seok Ho Kang; Jun Cheon; Je Jong Kim; Jeong Gu Lee

We aimed to compare the short‐term outcomes of men who had urodynamic evidence of detrusor underactivity (DU) or detrusor overactivity (DO) of a non‐neurogenic etiology as well as bladder outlet obstruction (BOO) and who underwent Holmium Laser Enucleation of the prostate (HoLEP). A database of 322 patients who underwent HoLEP between 2010 and 2014 was analyzed. Patients were classified into three groups according to the results of a preoperative urodynamic study. Preoperative parameters such as International Prostate Symptom Score (IPSS), Quality of Life (QoL) index, IPSS grade, uroflowmetry were compared with postoperative parameters measured at 6 months. There were 138 patients with BOO‐only and 89 patients with BOO and detrusor dysfunction including 56 with DO and 33 with DU. The degree of improvement in IPSS‐total (BOO: 10.7, DO: 8.3, DU: 7.0; p = 0.023) was greater in the BOO‐only group than in the DU group. There were more patients whose IPSS grade improved in the BOO‐only group (71%) than in the detrusor dysfunction group (DO: 53.6% and DU: 45.5%). Postoperative IPSS‐voiding (4.5 vs 7.0), and Qmax (18 vs 13.7) in the BOO‐only group were significantly better than those in the DU group. Additionally, postoperative IPSS‐storage (4.7 vs 6.7), and IPSS‐total (9.1 vs 12.3) in the BOO‐only group were significantly better than in the DO group (all p < 0.05). In conclusion, early surgical management for men with severe LUTS and associated BPH before secondary degeneration occurs may be beneficial for preserving detrusor function and yield better treatment outcomes.


Journal of Korean Medical Science | 2017

Oncologic Outcomes and Predictive Factors for Recurrence Following Robot-Assisted Radical Cystectomy for Urothelial Carcinoma: Multicenter Study from Korea

Ji Sung Shim; Tae Gyun Kwon; Koon Ho Rha; Young Goo Lee; Ji Youl Lee; Byong Chang Jeong; Jae Yoon Kim; Jong Hyun Pyun; Sung Gu Kang; Seok Ho Kang

The aim of our study was to evaluate intermediate-term oncologic outcomes, predictive factors for recurrence, and recurrence patterns in a multicenter series of patients treated with robot-assisted radical cystectomy (RARC) for urothelial carcinoma (UC) of the bladder. Between 2007 and 2015, 346 patients underwent RARC at multiple tertiary referral centers in Korea. Descriptive statistics were used for demographics and perioperative variables. Survival and recurrence were estimated with Kaplan-Meier analysis. Logistic regression models were used to determine predictors of recurrence. Median follow-up was 33 months (interquartile range [IQR], 7–50). The numbers of patients with organ-confined and lymph node (LN)-positive disease were 237 (68.4%) and 68 (19.7%), respectively. LN density (1–20 vs. > 20) was 13.6% and 6.1%, with a median of 17 nodes removed (IQR, 9–23). In logistic regression analysis, type of LN dissection, and pathologic tumor stage were significant predictors of cancer recurrence and death from cancer. Local, distal recurrence and secondary UC occurred in 7 (2.0%), 53 (15.3%), and 4 (1.2%) patients, respectively. The 5-year overall survival (OS), cancer-specific survival (CSS), and recurrence-free survival (RFS) were 78%, 84%, and 73%, respectively. At last follow-up, RFS for extended pelvic LN dissection vs. standard pelvic LN dissection was 70% and 47% (P = 0.038). In addition, at last follow-up, LN density (0 vs. 1–20 vs. over 20) was 67%, 41%, and 29%, respectively (P < 0.001). Patients undergoing RARC in this multi-institutional cohort demonstrated intermediate-term oncologic outcomes, predictive factors for recurrence, and recurrence patterns that were not unusual.


West Indian Medical Journal | 2013

Laparoscopic excision of a renal subcapsular abscess presenting as a subcapsular haematoma

Ji Sung Shim; Seung Min Jeong; Choi H; Tae Il Noh; Jong Hyun Pyun; Huy Kang Kim; Park Jy; Bae Jh; Je-Jong Kim

Renal subcapsular abscess is a very rare entity that is defined by a suppurative process localized to a space between the renal capsule and the renal parenchyma. The pathogenesis and aetiology of this entity remain speculative. To our knowledge, only five cases have been reported in the English literature. We describe a 74-year old woman with renal subcapsular abscess treated with laparoscopic removal and do a review of the literature.


The Journal of Sexual Medicine | 2017

392 Effect of Sleep Deprivation on the Male Reproductive System in Rats

Ji Sung Shim; J.H. Choi; Jong Hyun Pyun; Jang Ho Bae; D.G. Moon; J.J. Kim

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Jun Cheon

Korea University Medical Center

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