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Dive into the research topics where Robert Leung is active.

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Featured researches published by Robert Leung.


Urology | 2008

Robotic prostatectomy: a review of outcomes compared with laparoscopic and open approaches.

Roy Berryhill; J. Jhaveri; Rajiv Yadav; Robert Leung; Sandhya Rao; Assaad El-Hakim; Ashutosh Tewari

Prostate cancer affects the lives of millions of Americans each year. Since the advent of prostate-specific antigen testing, many cancers are found in initial stages and have the potential for curative resection; however, choosing which type of surgery to undergo can be a difficult task. This article reviews the outcomes of robotic prostatectomy in comparison with laparoscopic or open procedures. A PubMed search was performed to identify specific articles describing intraoperative details, surgical complications, cancer control, and continence and potency outcomes. Articles that revealed pertinent data were included in this study comparing robotic with laparoscopic or open prostatectomies.


BJUI | 2011

Anatomical grades of nerve sparing: a risk-stratified approach to neural-hammock sparing during robot-assisted radical prostatectomy (RARP).

Ashutosh Tewari; Abhishek Srivastava; Michael W. Huang; Brian D. Robinson; Maria M. Shevchuk; Matthieu Durand; Prasanna Sooriakumaran; Sonal Grover; Rajiv Yadav; Nishant Mishra; Sanjay R. Mohan; Danielle Brooks; Nusrat Shaikh; Abhinav Khanna; Robert Leung

Whats known on the subject? and What does the study add?


Journal of Endourology | 2010

Use of a novel absorbable barbed plastic surgical suture enables a "self-cinching" technique of vesicourethral anastomosis during robot-assisted prostatectomy and improves anastomotic times.

Ashutosh Tewari; Abhishek Srivastava; Prasanna Sooriakumaran; Adam Slevin; Sonal Grover; Olivia Waldman; Sivaram Rajan; Michael Herman; Roy Berryhill; Robert Leung

PURPOSE To demonstrate a novel technique of self-cinching anastomosis using a barbed and looped suture during robot-assisted radical prostatectomy (RARP). PATIENTS AND METHODS This is a feasibility study of 50 consecutive patients who underwent this novel self-cinching anastomotic technique using a V-Loc™ 180 absorbable barbed suture after RARP for clinically localized prostate cancer. The results were then compared with 50 consecutive patients who underwent RARP by the same surgeon before this new technique. We examined whether this novel technique had any effects on posterior reconstruction time, vesicourethral anastomosis time, and thus total reconstruction and operative time by inference. RESULTS The V-Loc 180 group had significantly shorter posterior reconstruction (40 seconds vs 60 seconds; P ≤ 0.001) and vesicourethral anastomotic times (7 min vs 12 min; P ≤ 0.001). By inference, this meant that total reconstruction and operative times were also significantly less (8 minutes vs 13.5 min; P ≤ 0.001 and 106 min vs 114.5 minutes; P ≤ 0.001, respectively). CONCLUSION We have shown that this technique is feasible and improves posterior reconstruction and anastomotic times. Further follow-up will determine any benefits of this technique on anastomotic urinary leak rates, continence, and catheter removal times.


European Urology | 2013

Effect of a Risk-stratified Grade of Nerve-sparing Technique on Early Return of Continence After Robot-assisted Laparoscopic Radical Prostatectomy

Abhishek Srivastava; Sameer Chopra; Anthony Pham; Prasanna Sooriakumaran; Matthieu Durand; Bilal Chughtai; Siobhan Gruschow; Alexandra Peyser; Niyati Harneja; Robert Leung; Richard K. Lee; Michael Herman; Brian D. Robinson; Maria M. Shevchuk; Ashutosh Tewari

BACKGROUND The impact of nerve sparing (NS) on urinary continence recovery after robot-assisted laparoscopic radical prostatectomy (RALP) has yet to be defined. OBJECTIVE To evaluate the effect of a risk-stratified grade of NS technique on early return of urinary continence. DESIGN, SETTING, AND PARTICIPANTS Data were collected from 1546 patients who underwent RALP by a single surgeon at a tertiary care center from December 2008 to October 2011. Patients were categorized preoperatively by a risk-stratified approach into risk grades 1-4, with risk grade 1 patients more likely to receive NS grade 1 or complete hammock preservation. This categorization was also conducted for risk grades 2-4, with grade 4 patients receiving a non-NS procedure. INTERVENTION Risk-stratified grading of NS RALP. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS Univariate and multivariate analysis identified predictors of early return of urinary continence, defined as no pad use at ≤ 12 wk postoperatively. RESULTS AND LIMITATIONS Early return of continence was achieved by 791 of 1417 men (55.8%); of those, 199 of 277 (71.8%) were in NS grade 1, 440 of 805 (54.7%) were in NS grade 2, 132 of 289 (45.7%) were in NS grade 3, and 20 of 46 (43.5%) were in NS grade 4 (p<0.001). On multivariate analysis, better NS grade was a significant independent predictor of early return of urinary continence when NS grade 1 was the reference variable compared with NS grade 2 (p<0.001; odds ratio [OR]: 0.46), NS grade 3 (p<0.001; OR: 0.35), and NS grade 4 (p=0.001; OR: 0.29). Lower preoperative International Prostate Symptom Score (p=0.001; OR: 0.97) and higher preoperative Sexual Health Inventory for Men score (p=0.002; OR: 1.03) were indicative of early return of urinary continence. Positive surgical margin rates were 7.2% (20 of 277) of grade 1 cases, 7.6% (61 of 805) of grade 2 cases, 7.6% (22 of 289) of grade 3 cases, and 17.4% (8 of 46) of grade 4 cases (p=0.111). Extraprostatic extension occurred in 6.1% (17 of 277) of NS grade 1 cases, 17.5% (141 of 805) of NS grade 2 cases, 42.5% (123 of 289) of NS grade 3 cases, and 63% (29 of 46) of NS grade 4 cases (p<0.001). Some limitations of the study are that the study was not randomized, grading of NS was subjective, and possible selection bias existed. CONCLUSIONS Our study reports a correlation between risk-stratified grade of NS technique and early return of urinary continence as patients with a lower grade (higher degree) of NS achieved an early return of urinary continence without compromising oncologic safety.


Expert Review of Anticancer Therapy | 2006

Robotic prostatectomy: a pooled analysis of published literature

Assaad El-Hakim; Robert Leung; Ashutosh Tewari

Objective: Robotic prostatectomy has been recently added to the treatment armamentarium of localized prostate cancer. We reviewed published data on this modality with critical appraisal of outcomes and complications. Methods: A Medline® search was performed that encompassed all published articles on robotic prostatectomy. Select data on open radical retropubic (RRP) and laparoscopic (LP) prostatectomy from centers of excellence in the USA and Europe were included for objective comparison. Perioperative parameters, pathological results, including surgical margin rate, complications and postoperative continence and potency rates were reported. Advantages and shortcomings of robotic prostatectomy, and the learning curve and cost issues were also addressed. Results: Robotic prostatectomy offers advantages of minimally invasive access surgery, including enhanced visualization, decreased bleeding and transfusion rate, shorter hospital stay and faster recovery. Pathological outcomes are comparable to RRP and LP with acceptable positive margin rate. At short-term follow-up, continence and potency results appear to be equivalent to RRP and LP. The learning curve of robotic prostatectomy is faster than that of LP. Cost remains a matter of debate at the present time. Long-term cancer control results of robotic prostatectomy are still maturing. Conclusions: Robotic prostatectomy is a promising minimally invasive surgical approach for men with localized prostate cancer. Short-term clinical and pathological results compare favorably to RRP and LP.


BJUI | 2008

Cancer control and the preservation of neurovascular tissue: How to meet competing goals during robotic radical prostatectomy

Ashutosh Tewari; Sandhya Rao; Juan I. Martínez-Salamanca; Robert Leung; Rajan Ramanathan; Anil Mandhani; E. Darracott Vaughan; Mani Menon; Wolfgang Horninger; Jiangling Tu; Georg Bartsch

Study Type – Therapy (case series) 
Level of Evidence 4


Proceedings of the National Academy of Sciences of the United States of America | 2012

Genetic and functional analyses implicate the NUDT11, HNF1B, and SLC22A3 genes in prostate cancer pathogenesis

Chiara Grisanzio; Lillian Werner; David Y. Takeda; Bisola C. Awoyemi; Mark Pomerantz; Hiroki Yamada; Prasanna Sooriakumaran; Brian D. Robinson; Robert Leung; Anna C. Schinzel; Ian G. Mills; Helen Ross-Adams; David E. Neal; Masahito Kido; Toshihiro Yamamoto; Gillian Petrozziello; Edward C. Stack; Rosina T. Lis; Philip W. Kantoff; Massimo Loda; Oliver Sartor; Shin Egawa; Ashutosh Tewari; William C. Hahn; Matthew L. Freedman

One of the central goals of human genetics is to discover the genes and pathways driving human traits. To date, most of the common risk alleles discovered through genome-wide association studies (GWAS) map to nonprotein-coding regions. Because of our relatively poorer understanding of this part of the genome, the functional consequences of trait-associated variants pose a considerable challenge. To identify the genes through which risk loci act, we hypothesized that the risk variants are regulatory elements. For each of 12 known risk polymorphisms, we evaluated the correlation between risk allele status and transcript abundance for all annotated protein-coding transcripts within a 1-Mb interval. A total of 103 transcripts were evaluated in 662 prostate tissue samples [normal (n = 407) and tumor (n = 255)] from 483 individuals [European Americans (n = 233), Japanese (n = 127), and African Americans (n = 123)]. In a pooled analysis, 4 of the 12 risk variants were strongly associated with five transcripts (NUDT11, MSMB, NCOA4, SLC22A3, and HNF1B) in histologically normal tissue (P ≤ 0.001). Although associations were also observed in tumor tissue, they tended to be more attenuated. Previously, we showed that MSMB and NCOA4 participate in prostate cancer pathogenesis. Suppressing the expression of NUDT11, SLC22A3, and HNF1B influences cellular phenotypes associated with tumor-related properties in prostate cancer cells. Taken together, the data suggest that these transcripts contribute to prostate cancer pathogenesis.


BJUI | 2010

Anatomical retro-apical technique of synchronous (posterior and anterior) urethral transection: a novel approach for ameliorating apical margin positivity during robotic radical prostatectomy.

Ashutosh Tewari; Abhishek Srivastava; Kumaran Mudaliar; Gerald Y. Tan; Sonal Grover; Youssef El Douaihy; David Peters; Robert Leung; Rajiv Yadav; Majnu John; James S. Wysock; E. Daracott Vaughan; Sara Muir; Mahul B. Amin; Mark A. Rubin; Jiangling Tu; Mohammed Akthar; Maria M. Shevchuk

Study Type – Therapy (case series)
Level of Evidence 4


World Journal of Urology | 2006

Anatomy of autonomic nerve component in the male pelvis: the new concept from a perspective for robotic nerve sparing radical prostatectomy

Atsushi Takenaka; Robert Leung; Masato Fujisawa; Ashutosh Tewari

The DaVinci Robot (Intuitive Surgical, Sunnyvale California) with its magnified 3-D vision and multi-jointed wristed instruments enabled us to perform radical prostatectomy with consideration for the pelvic anatomy. In the present paper, we review the pelvic autonomic neuroanatomy with respect to robotic prostatectomy and demonstrate the procedures and critical points of nerve-sparing robotic radical prostatectomy based on novel anatomic concepts. Microscopic and macroscopic data were acquired from 30 fresh and 25 fixed male cadavers. A video study of 205 surgeries was performed for establishing the anatomy relevant to robotic prostatectomy. From a practical standpoint, we could group the relevant neural tissue into three broad zones: (1) proximal neurovascular plate (PNP), (2) predominant neurovascular bundles (PNB), (3) accessory distal neural pathways (ANP). Autonomic ganglion cells existed widely not only in nerve components but also along the viscera. The critical areas of nerve sparing surgery were the distal end of PNP, the entire PNB, and the circumference of the apex. Interindividual differences of cell counts were evident in all sites. Based on these concepts, we established the Athermal Robotic Technique (ART) for nerve sparing prostatectomy. Surgical and oncological outcomes were not mature but feasible. These tri-zonal and ganglion cell concepts may be of benefit to new surgeons undertaking nerve-sparing robotic radical prostatectomy.


BJUI | 2010

Visual cues as a surrogate for tactile feedback during robotic-assisted laparoscopic prostatectomy: posterolateral margin rates in 1340 consecutive patients.

Ashutosh Tewari; Nishant Patel; Robert Leung; Rajiv Yadav; E. Darracott Vaughan; Youssef El-Douaihy; Jiangling J Tu; Muhul B. Amin; Mohammed Akhtar; Mark Burns; Usha Kreaden; Mark A. Rubin; Atsushi Takenaka; Maria M. Shevchuk

Study Type – Therapy (case series)
Level of Evidence 4

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Ashutosh Tewari

Icahn School of Medicine at Mount Sinai

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