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Featured researches published by John Pattaras.


European Urology | 2013

Complications After Robot-assisted Radical Cystectomy: Results from the International Robotic Cystectomy Consortium

Raza Johar; Matthew H. Hayn; Andrew P. Stegemann; Kamran Ahmed; Piyush K. Agarwal; M. Derya Balbay; Ashok K. Hemal; Adam S. Kibel; Fred Muhletaler; Kenneth G. Nepple; John Pattaras; James O. Peabody; Joan Palou Redorta; Koon Ho Rha; Lee Richstone; Matthias Saar; Francis Schanne; Douglas S. Scherr; S. Siemer; Michael Stökle; Alon Z. Weizer; Peter Wiklund; Timothy Wilson; Michael Woods; Bertrum Yuh; Khurshid A. Guru

BACKGROUND Complication reporting is highly variable and nonstandardized. Therefore, it is imperative to determine the surgical outcomes of major oncologic procedures. OBJECTIVE To describe the complications after robot-assisted radical cystectomy (RARC) using a standardized and validated reporting methodology. DESIGN, SETTING, AND PARTICIPANTS Using the International Robotic Cystectomy Consortium (IRCC) database, we identified 939 patients who underwent RARC, had available complication data, and had at least 90 d of follow-up. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS Complications were analyzed and graded according to the Memorial Sloan-Kettering Cancer Center (MSKCC) system and were defined and stratified by organ system. Secondary outcomes included identification of preoperative and intraoperative variables predicting complications. Logistic regression models were used to define predictors of complications and readmission. RESULTS AND LIMITATIONS Forty-one percent (n=387) and 48% (n=448) of patients experienced a complication within 30 and 90 d of surgery, respectively. The highest grade of complication was grade 0 in 52%, grade 1-2 in 29%, and grade 3-5 in 19% patients. Gastrointestinal, infectious, and genitourinary complications were most common (27%, 23%, and 17%, respectively). On multivariable analysis, increasing age group, neoadjuvant chemotherapy, and receipt of blood transfusion were independent predictors of any and high-grade complications, respectively. Thirty and 90-d mortality was 1.3% and 4.2%, respectively. As a multi-institutional database, a disparity in patient selection, operating standards, postoperative management, and reporting of complications can be considered a major limitation of the study. CONCLUSIONS Surgical morbidity after RARC is significant when reported using a standardized reporting methodology. The majority of complications are low grade. Strict reporting of complications is necessary to advocate for radical cystectomy (RC) and helps in patient counseling.


The Journal of Molecular Diagnostics | 2005

Molecular classification of renal tumors by gene expression profiling.

Audrey N. Schuetz; Qiqin Yin-Goen; Mahul B. Amin; Carlos S. Moreno; Cynthia Cohen; Christopher D. Hornsby; Wen Li Yang; John A. Petros; Muta M. Issa; John Pattaras; Kenneth Ogan; Fray F. Marshall; Andrew N. Young

Renal tumor classification is important because histopathological subtypes are associated with distinct clinical behavior. However, diagnosis is difficult because tumor subtypes have overlapping microscopic characteristics. Therefore, ancillary methods are needed to optimize classification. We used oligonucleotide microarrays to analyze 31 adult renal tumors, including clear cell renal cell carcinoma (RCC), papillary RCC, chromophobe RCC, oncocytoma, and angiomyolipoma. Expression profiles correlated with histopathology; unsupervised algorithms clustered 30 of 31 tumors according to appropriate diagnostic subtypes while supervised analyses identified significant, subtype-specific expression markers. Clear cell RCC overexpressed proximal nephron, angiogenic, and immune response genes, chromophobe RCC oncocytoma overexpressed distal nephron and oxidative phosphorylation genes, papillary RCC overexpressed serine protease inhibitors, and extracellular matrix products, and angiomyolipoma overexpressed muscle developmental, lipid biosynthetic, melanocytic, and distinct angiogenic factors. Quantitative reverse transcriptase-polymerase chain reaction and immunohistochemistry of formalin-fixed renal tumors confirmed overexpression of proximal nephron markers (megalin/low-density lipoprotein-related protein 2, alpha-methylacyl CoA racemase) in clear cell and papillary RCC and distal nephron markers (beta-defensin 1, claudin 7) in chromophobe RCC/oncocytoma. In summary, renal tumor subtypes were classified by distinct gene expression profiles, illustrating tumor pathobiology and translating into novel molecular bioassays using fixed tissue.


European Urology | 2014

Analysis of intracorporeal compared with extracorporeal urinary diversion after robot-assisted radical cystectomy: Results from the international robotic cystectomy consortium

Kamran Ahmed; Shahid Khan; Matthew H. Hayn; Piyush K. Agarwal; Ketan K. Badani; M. Derya Balbay; Erik P. Castle; Prokar Dasgupta; Reza Ghavamian; Khurshid A. Guru; Ashok K. Hemal; Brent K. Hollenbeck; Adam S. Kibel; Mani Menon; Alex Mottrie; Kenneth G. Nepple; John Pattaras; James O. Peabody; Vassilis Poulakis; Raj S. Pruthi; Joan Palou Redorta; Koon Ho Rha; Lee Richstone; Matthias Saar; Douglas S. Scherr; S. Siemer; Michael Stoeckle; Eric Wallen; Alon Z. Weizer; Peter Wiklund

BACKGROUND Intracorporeal urinary diversion (ICUD) has the potential benefits of a smaller incision, reduced pain, decreased bowel exposure, and reduced risk of fluid imbalance. OBJECTIVE To compare the perioperative outcomes of patients undergoing extracorporeal urinary diversion (ECUD) and ICUD following robot-assisted radical cystectomy (RARC). DESIGN, SETTING, AND PARTICIPANTS We reviewed the database of the International Robotic Cystectomy Consortium (IRCC) (18 international centers), with 935 patients who had undergone RARC and pelvic lymph node dissection (PLND) between 2003 and 2011. INTERVENTION All patients within the IRCC underwent RARC and PLND as indicated. The urinary diversion was performed either intracorporeally or extracorporeally. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS Demographic data, perioperative outcomes, and complications in patients undergoing ICUD or ECUD were compared. All patients had at least a 90-d follow-up. The Fisher exact test was used to summarize categorical variables and the Wilcoxon rank sum test or Kruskal-Wallis test for continuous variables. RESULTS AND LIMITATIONS Of 935 patients who had RARC and PLND, 167 patients underwent ICUD (ileal conduit: 106; neobladder: 61), and 768 patients had an ECUD (ileal conduit: 570; neobladder: 198). Postoperative complications data were available for 817 patients, with a minimum follow-up of 90 d. There was no difference in age, gender, body mass index, American Society of Anesthesiologists grade, or rate of prior abdominal surgery between the groups. The operative time was equivalent (414 min), with the median hospital stay being marginally longer for the ICUD group (9 d vs 8 d, p=0.086). No difference in the reoperation rates at 30 d was noted between the groups. The 90-d complication rate was not significant between the two groups, but a trend favoring ICUD over ECUD was noted (41% vs 49%, p=0.05). Gastrointestinal complications were significantly lower in the ICUD group (p ≤ 0.001). Patients with ICUD were at a lower risk of experiencing a postoperative complication at 90 d (32%) (odds ratio: 0.68; 95% confidence interval, 0.50-0.94; p=0.02). Being a retrospective study was the main limitation. CONCLUSIONS Robot-assisted ICUD can be accomplished safely, with comparable outcomes to open urinary diversion. In this cohort, patients undergoing ICUD had a relatively lower risk of complications.


Journal of Endourology | 2002

Second Prize: Renal Hypothermia Achieved by Retrograde Intracavitary Saline Perfusion

Jaime Landman; Jamil Rehman; Chandru P. Sundaram; Sam B. Bhayani; Manoj Monga; John Pattaras; Neriman Gokden; Peter A. Humphrey; Ralph V. Clayman

BACKGROUND AND PURPOSE Hypothermia during vascular clamping protects the kidney from ischemia-induced nephron loss. Traditionally, cooling is achieved by packing the kidney in ice, which lowers the temperature of the rest of the surgical field as well, and the method cannot be used during laparoscopy. We evaluated the utility of a newly developed ureteral access system for circulating ice-cold saline. MATERIALS AND METHODS Domestic pigs underwent retrograde endoscopic cooling through an access sheath without (N = 2) or with (N = 3) renal artery occlusion, traditional ice-slush cooling with renal artery occlusion (N = 3), or occlusion without hypothermia (N = 3). Five days later, the pigs were sacrificed and the kidneys and ureters examined histologically. RESULTS Endoscopic cooling with renal artery occlusion and ice-slush cooling both produced renal hypothermia. The former produced medullary and cortical temperatures of 21.3 degrees C and 27.3 degrees C, respectively, and the latter medullary and cortical temperatures of 28.8 degrees C and 23.7 degrees C, respectively. Histologically, there were minimal changes in the first three groups, whereas venous congestion, multifocal chronic inflammation, and periarteriolar hemorrhage were seen after renal artery occlusion without hypothermia. CONCLUSION Retrograde endoscopic renal hypothermia is effective and requires no novel equipment or special surgical skills. Clinical application has not yet been attempted.


The Journal of Urology | 2002

Comparison of Hand Assisted and Standard Laparoscopic Radical Nephroureterectomy for the Management of Localized Transitional Cell Carcinoma

Jaime Landman; Ronan Y. Lev; Sam B. Bhayani; Gregory F. Alberts; Jamil Rehman; John Pattaras; R. Sherburne Figenshau; Adam S. Kibel; Ralph V. Clayman; Elspeth M. McDougall

PURPOSE Hand assisted laparoscopy affords the surgeon tactile sensation and blunt dissection, which are currently limited using the standard laparoscopic technique. Therefore, we compared standard and hand assisted laparoscopic radical nephroureterectomy for localized upper tract transitional cell carcinoma. MATERIALS AND METHODS The medical records of 27 patients who underwent standard (11) or hand assisted (16) laparoscopic radical nephroureterectomy between April 1998 and January 2001 were retrospectively reviewed. The parameters of efficacy, efficiency, safety and convalescence were compared. RESULTS Mean patient age was 64 and 66 years (p = 0.72) in the standard and hand assisted groups, and the mean American Society of Anesthesiologists score was 2.5 and 2.7 (p = 0.64), respectively. All standard and 15 of the 16 hand assisted (94%) procedures were successfully completed via laparoscopy. Total operative time was more than 1 hour shorter for hand assisted than for laparoscopic radical nephroureterectomy (4.9 versus 6.1 hours, p = 0.055). Mean estimated blood loss was similar in the standard and hand assisted groups (190 and 201 ml., p = 0.78). In each group 1 patient required blood transfusion. Mean specimen weight was significantly higher in hand assisted cases (576 versus 335 gm., p = 0.036). Mean time to oral intake was similar in patients who underwent standard and hand assisted laparoscopic radical nephroureterectomy (13 and 20 hours, respectively, p = 0.45). The mean analgesic requirement was also similar (29 and 33 mg. morphine sulfate, respectively, p = 0.83). Mean hospital stay in uncomplicated cases was similar for standard and hand assisted surgery (2.9 and 2.5 days, respectively). Overall hospital stay in the 2 cohorts was also similar (3.3 and 4.5 days, respectively, p = 0.59). Four patients per group experienced postoperative complications. There were no deaths in the standard group but 1 patient (6%) in the hand assisted group died postoperatively. Mean time to partial and complete convalescence in the standard and hand assisted groups was 2.4 and 5.2, and 3.5 and 8.0 weeks, while mean followup was 27.4 and 9.6 months, respectively. CONCLUSIONS Compared with standard laparoscopy hand assisted laparoscopy decreases operative time without significantly altering short-term parameters of convalescence. However, long-term convalescence after hand assisted laparoscopic radical nephroureterectomy is 1 to 3 weeks longer (p = 0.27). Longer followup in the hand assisted cohort is necessary to determine whether there are any differences in the 2 methods in regard to cancer control.


The Journal of Urology | 2003

Matched pair analysis of shock wave lithotripsy effectiveness for comparison of lithotriptors

Andrew J. Portis; Yan Yan; John Pattaras; Cassio Andreoni; Robert G. Moore; Ralph V. Clayman

PURPOSE In an effort to streamline a comparison of the effectiveness of a new lithotriptor with the standard HM3 lithotriptor (Dornier Medical Systems, Inc., Marietta, Georgia) we used a matched pair analysis design. A matched design often provides more efficient estimates (smaller variances) than an unmatched design given the same sample size. MATERIALS AND METHODS Patients with solitary renal or ureteral calculi treated on a LithoTron shock wave lithotriptor (HealthTronics, Marietta, Georgia) between October 1999 and February 2000 with a minimum followup of 3 months were identified. Evaluable patients treated with the LithoTron were matched using 5 parameters to a data base of patients treated with an unmodified HM3 shock wave lithotriptor between October 1997 and February 2000. Matching criteria consisted of calculus side, calculus location (1 of 7 categories), maximum stone diameter (+/-2 mm.), minimum stone diameter (+/-2 mm.) and patient body mass index (BMI +/-6). When more than 1 match was suitable, matching was directed by random numbers. Following matching, clinical charts and radiographic reports were evaluated for stone clearance and post-shock wave lithotripsy interventions. Stone treatment success was defined as residual fragments less than 2 mm. without need for further intervention. RESULTS A total of 94 potentially evaluable patients treated with the LithoTron were identified and 38 matched pairs were created. Average maximum stone diameter, minimum stone diameter, and BMI were 9.6 and 9.9 mm., 6.7 and 6.8 mm. and 29.3 and 28.9 kg./m. for HM3 and LithoTron cases, respectively. All calculi were radiopaque and consisted of mixed calcium oxalate monohydrate (19 and 13), calcium oxalate dihydrate (1 and 1) or calcium phosphate (2 and 2) in the HM3 and LithoTron groups, respectively. Patients were not specifically matched on stone composition because of incomplete availability. Overall intervention-free, stone treatment success rate was 79% for the HM3 and 58% for the LithoTron. OR for failure of LithoTron versus HM3 treatment was 3.004 (McNemar test p = 0.08). There were 16 discordant pairs. In 4 cases LithoTron was successful and HM3 failed, and in 12 cases LithoTron failed and HM3 was successful. Subgroup analysis revealed a trend for LithoTron treatment failure for lower pole calculi, calculi 10 mm. or greater and BMI of 30 kg./m. or greater. CONCLUSIONS In this initial evaluation the HM3, despite a relatively small study sample size, appeared to provide superior clinical results to the LithoTron (p = 0.08). The use of matched pair analysis using a large cohort of patients treated with the HM3 for retrospective matching may allow for accurate determination of the effectiveness of new lithotripsy technology with a relatively small clinical study group.


The Journal of Urology | 2010

Absolute Preoperative C-Reactive Protein Predicts Metastasis and Mortality in the First Year Following Potentially Curative Nephrectomy for Clear Cell Renal Cell Carcinoma

Timothy V. Johnson; Ammara Abbasi; Ashli Owen-Smith; Andrew N. Young; Kenneth Ogan; John Pattaras; Fray F. Marshall; Viraj A. Master

PURPOSE C-reactive protein is an inflammatory biomarker associated with tumor burden and metastasis in renal cell carcinoma. Recent studies suggest that preoperative C-reactive protein predicts metastasis and mortality after nephrectomy for localized renal cell carcinoma. However, these studies dichotomized C-reactive protein (typically 10 mg/l or greater vs less than 10 mg/l). Considering the continuous range of C-reactive protein (less than 1 mg/l to greater than 100 mg/l) we assessed the ability of absolute preoperative C-reactive protein to predict metastases and mortality as a continuous variable. MATERIALS AND METHODS Patients with clinically localized (T1-T3N0M0) clear cell renal cell carcinoma were followed for 1 year postoperatively. Metastases were identified radiologically and mortality was determined by death certificate. Univariate and multivariate binary logistic regression analyses examined 1-year relapse-free survival and overall relative survival across patient and disease characteristics. RESULTS Of the 130 patients in this study metastases developed in 24.6% and 10.8% of the patients died. Mean (SD) preoperative C-reactive protein for patients in whom metastases did and did not develop was 89.17 (74.17) and 9.16 (30.62) mg/l, respectively. Mean preoperative C-reactive protein for patients who did and did not die was 102.61 (77.32) and 19.52 (46.10) mg/l, respectively. On multivariate analysis SSIGN score (p <0.001) and preoperative C-reactive protein (B 0.027, SE 0.003, p <0.001) were significant predictors of relapse-free survival, and preoperative platelets (p = 0.009) and preoperative C-reactive protein (B 0.011, SE 0.008, p <0.001) were significant predictors of overall relative survival. CONCLUSIONS Absolute preoperative C-reactive protein is a robust predictor of metastasis and mortality after nephrectomy for localized renal cell carcinoma. Clinicians should consider absolute preoperative C-reactive protein to identify high risk patients for closer surveillance or additional therapy. In addition, predictive algorithms and models of metastasis should consider incorporating C-reactive protein as a continuous variable to maximize predictive ability.


Urology | 2002

Incidence of postoperative adhesion formation after transperitoneal genitourinary laparoscopic surgery

John Pattaras; Robert G. Moore; Jaime Landman; Ralph V. Clayman; Gunter Janetschek; Elspeth M. McDougall; Steven Docimo; Raul O. Parra; Louis R. Kavoussi

OBJECTIVES To evaluate adhesion formation after urologic laparoscopy, a multi-institutional review was conducted among adult patients who underwent a second procedure after an initial transperitoneal laparoscopic procedure. Adhesion formation after abdominal surgery remains a major cause of postoperative morbidity. Peritoneal adhesions result in hospitalizations and interventions that result in healthcare costs of more than 1 billion dollars annually. The risk of adhesion formation from transperitoneal genitourinary laparoscopy in adults has not been previously studied. METHODS Twenty-seven patients (mean age 45.5 years, range 24 to 71) were identified who underwent a second laparoscopic procedure after their initial urologic laparoscopic procedure was performed. The mean time between the procedures was 11.4 months (range 8 days to 38 months). At the time of the repeated laparoscopy or open surgery, the peritoneal cavity was examined and mapped for type (grade), extent (length), and location of any adhesions at the operative and trocar sites. The adhesions were graded as 0, no adhesions; 1, flimsy; 2, dense; and 3, cohesive. The extent was graded as 0, no adhesions; 1, less than 2 cm; 2, 2.1 to 10 cm; 3, greater than 10.1 cm. RESULTS Overall, adhesions occurred in 6 (22.2%) of 27 patients. Operative site adhesions occurred in only 3 (8.2%) of 34 possible operative sites (gastric augmentation cystoplasty, renal cyst ablation, nephropexy). Trocar site adhesions occurred in 4 (3.5%) of 114 possible sites (two nephrectomies, one cyst decortication, and one orchiectomy). All adhesions were classified as grade 1 and extent 1, except for a single grade 2, extent 2 adhesion. In most patients, retroperitonealization occurred with minimal or no scarring noted. None of the patients developed symptoms as a result of the adhesion formation. CONCLUSIONS Although intraperitoneal adhesions do occur with adult urologic laparoscopy, the incidence is low. Also, in the few patients who do form adhesions, they are flimsy and short. This evidence, when contrasted with the available data on adhesion formation after open surgery, suggests that transperitoneal laparoscopic approaches to genitourinary surgery may have advantages over traditional open transperitoneal approaches by lowering the incidence and severity of adhesion formation.


Journal of Magnetic Resonance Imaging | 2010

Acute abdominal pain: Is there a potential role for MRI in the setting of the emergency department in a patient with renal calculi?

Bobby Kalb; Puneet Sharma; Khalil Salman; Kenneth Ogan; John Pattaras; Diego R. Martin

Acute flank pain is a frequent clinical presentation encountered in emergency departments, and a work‐up for obstructive urolithiasis in this setting is a common indication for computed tomography (CT). However, imaging alternatives to CT for the evaluation of renal colic are warranted in some clinical situations, such as younger patients, pregnancy, patients that have undergone multiple prior CT exams and also patients with vague clinical presentations. MRI, although relatively insensitive for the direct detection of urinary calculi, has the ability to detect the secondary effects of obstructive urolithiasis. Using rapid, single shot T2‐weighted sequences without and with fat saturation provides an abdominopelvic MR examination that can detect the sequelae of clinically active stone disease, in addition to alternate inflammatory processes that may mimic the symptoms of renal colic. In addition, MR nephro‐urography (MRNU) has the ability to provide quantitative analysis of renal function that has the potential to direct clinical management in the setting of obstructing calculi. This review describes the potential utility and limitations of MRI in the emergency setting for diagnosing causes of flank pain and renal colic, particularly in patients with unusual presentations or when an alternative to CT may be warranted. J. Magn. Reson. Imaging 2010;32:1012–1023.


BJUI | 2013

Impact of surgeon and volume on extended lymphadenectomy at the time of robot-assisted radical cystectomy: results from the International Robotic Cystectomy Consortium (IRCC)

Susan Marshall; Matthew H. Hayn; Andrew P. Stegemann; Piyush K. Agarwal; Ketan K. Badani; M. Derya Balbay; Prokar Dasgupta; Ashok K. Hemal; Brent K. Hollenbeck; Adam S. Kibel; Mani Menon; Alex Mottrie; Kenneth G. Nepple; John Pattaras; James O. Peabody; Vassilis Poulakis; Raj S. Pruthi; Joan Palou Redorta; Koon Ho Rha; Lee Richstone; Francis Schanne; Douglas S. Scherr; S. Siemer; M. Stöckle; Eric Wallen; Alon Z. Weizer; Peter Wiklund; Timothy Wilson; Michael Woods; Khurshid A. Guru

Lymph node dissection and its extend during robot‐assisted radical cystectomy varies based on surgeon related factors. This study reports outcomes of robot‐assisted extended lymphadenectomy based on surgeon experience in both academic and private practice settings.

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Adam S. Kibel

Brigham and Women's Hospital

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Ashok K. Hemal

Wake Forest Baptist Medical Center

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Joan Palou Redorta

Autonomous University of Barcelona

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