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Dive into the research topics where Vassilis Poulakis is active.

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Featured researches published by Vassilis Poulakis.


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.


BJUI | 2008

A comparison of urinary nuclear matrix protein-22 and bladder tumour antigen tests with voided urinary cytology in detecting and following bladder cancer:the prognostic value of false-positive results

Vassilis Poulakis; U. Witzsch; R. De Vries; Hans-Michael Altmannsberger; M.J. Manyak; E. Becht

Objectives To evaluate the diagnostic and prognostic value of the nuclear matrix protein‐22 (NMP22) and bladder tumour antigen (BTAstat) tests compared with voided urinary cytology (VUC) in detecting and following bladder cancer, assessing particularly the prognostic value of false‐positive test results in patients followed up for bladder cancer.


Fertility and Sterility | 2001

Birth of two infants with normal karyotype after intracytoplasmic injection of sperm obtained by testicular extraction from two men with nonmosaic Klinefelter’s syndrome

Vassilis Poulakis; U. Witzsch; Wolfgang Diehl; Rachelle de Vries; Eduard Becht; Siegfried Trotnow

OBJECTIVE To report two births of a healthy male and a healthy female baby after use of testicular spermatozoa from two patients with nonmosaic Klinefelters syndrome. DESIGN Case report. SETTING General academic hospital with IVF center and university institute of human genetics. PATIENT(S) Two couples with primary infertility in which the men had secretory azoospermia and nonmosaic 47,XXY karyotype. Both women had a normal karyotype and no gynecologic abnormalities. INTERVENTION(S) ICSI was performed using testicular spermatozoa after ovarian stimulation and transvaginal ultrasonography-guided oocyte pick-up. MAIN OUTCOME MEASURE(S) Normal fertilization, embryo cleavage, clinical pregnancy outcome, and peripheral blood karyotype of the newborn. RESULT(S) In each case, 13 metaphase II oocytes were injected, of which 7 fertilized normally. Three good-quality embryos (4-cell stage) were transferred into the uterine cavity. Both women conceived, and normal pregnancies followed. Genetic analysis of the neonates revealed normal 46,XX and 46,XY karyotypes. CONCLUSION(S) These case reports reaffirm that patients with nonmosaic Klinefelters syndrome produce normal spermatozoa with fertilization potential. Although it is premature to make conclusions about the rate of transmission of this aneuploidy because of the low number of the published cases, this report substantiates the idea that rates of transmission of this gonosomal aneuploidy are low.


Urology | 2011

Surgery-related Complications of Robot-assisted Radical Cystectomy With Intracorporeal Urinary Diversion

Martin Schumacher; Martin Jonsson; Abolfazl Hosseini; Tommy Nyberg; Vassilis Poulakis; Hubert John; Peter Wiklund

OBJECTIVES To assess the surgery-related complications at robot-assisted radical cystectomy with total intracorporeal urinary diversion during our learning curve in treating 45 patients with bladder cancer. METHODS A total of 45 patients were pooled in 3 consecutive groups of 15 cases each to evaluate the complications according to the Clavien classification. As a surrogate for our learning curve, the following parameters were assessed: operative time, blood loss, urinary diversion type, lymph node yield, surgical margin status, and length of hospital stay. RESULTS Early surgery-related complications were noted in 40% of the patients and late complications in 30%. The early Clavien grade III complications remained significant (27%) and did not decline with time. Overall, fewer complications were observed between the groups over time, with a significant decrease in late versus early complications (P = .005 and P = .058). The mean operative times declined from the first group to the second and third groups (P = .005) and the hospital stays shortened (P = .006). No significant difference was observed between groups regarding the lymph node yield at cystectomy (P = .108), with a mean of 22.5 nodes (range 10-52) removed. More patients received an orthotopic bladder substitute (Studer) in each of the latter 2 groups than in the first. CONCLUSIONS Although robot-assisted radical cystectomy with total intracorporeal urinary diversion is a complex procedure, we observed decreased surgery-related complications and improved outcomes over time in the present series. Our results need to be confirmed by others before robot-assisted radical cystectomy with totally intracorporeal urinary diversion can be accepted as a treatment option for patients with bladder cancer.


Urology | 2004

Preoperative neural network using combined magnetic resonance imaging variables, prostate-specific antigen, and Gleason score for predicting prostate cancer biochemical recurrence after radical prostatectomy

Vassilis Poulakis; U. Witzsch; Rachelle de Vries; Volker Emmerlich; Michael Meves; Hans-Michael Altmannsberger; Eduard Becht

OBJECTIVES To develop and test an artificial neural network (ANN) for predicting biochemical recurrence based on the combined use of pelvic coil magnetic resonance imaging (pMRI), prostate-specific antigen (PSA) measurement, and biopsy Gleason score, after radical prostatectomy and to investigate whether it is more accurate than logistic regression analysis (LRA) in men with clinically localized prostate cancer. METHODS We evaluated 191 consecutive men who had undergone retropubic radical prostatectomy for clinically localized prostate cancer. None of the men had lymph node metastasis as determined by adequate follow-up and pathologic criteria. The preoperative predictive variables included clinical TNM stage, serum PSA level, biopsy Gleason score, and pMRI findings. The predicted result was biochemical failure (PSA level of 0.1 ng/mL or greater). The patient data were randomly split into four cross-validation sets and used to develop and validate the LRA and ANN models. The predictive ability of the ANN was compared with that of LRA, Han tables, and the Kattan nomogram using area under the receiver operating characteristic curve (AUROC) analysis. RESULTS Of the 191 patients, 57 (30%) developed disease progression at a median follow-up of 64 months (mean 61, range 2 to 86). Using all the input variables, the AUROC of the ANN was significantly greater (P <0.05) than the AUROC of LRA, Han tables, or the Kattan nomogram for the prediction of PSA recurrence 5 years after radical prostatectomy (0.897 +/- 0.063 versus 0.785 +/- 0.060, 0.733 +/- 0.061, and 0.737 +/- 0.071, respectively). Removing the pMRI findings from the previous models, the AUROC of the ANN decreased statistically significantly (P <0.05) and was comparable to the AUROC of conventional predictive tools (P >0.05). CONCLUSIONS Using the pMRI findings, the ANN was superior to LRA, predictive tables, and nomograms to predict biochemical recurrence accurately. Confirmatory studies are warranted.


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.


Urology | 2003

Cold-knife endoureterotomy for nonmalignant ureterointestinal anastomotic strictures

Vassilis Poulakis; U. Witzsch; Rachelle de Vries; Eduard Becht

OBJECTIVES To evaluate the long-term results of cold-knife incision (CNI) of nonmalignant ureterointestinal anastomosis strictures (UASs) after urinary diversion in a consecutive series of patients. METHODS Since 1994, we have evaluated retrospectively 40 patients with 43 UASs, who were primarily treated with CNI (group 1). Six patients from group 1 with 7 UASs who failed primary CNI comprised group 2. After placement of an 8F nephrostomy tube, a 0.035-inch guidewire bypassed the stricture in an antegrade fashion under guidance of a centrally opened ureteral catheter (5F). A wire-mounted cold-knife was pulled through the strictured area in retrograde fashion under fluoroscopic control. Postoperatively, an 8 to 12F stent was left indwelling for 6 to 12 weeks. Successful treatment was defined as radiographic and scintigraphic resolution of obstruction and symptomatic relief. RESULTS In group 1, after removal of the stent, the ureteroenteric area remained patent in 26 (60.5%) of 43 UASs during a follow-up period of 38.8 months (range 12 to 85). The success rate at 1, 2, and 3 years was 86%, 67.8%, and 60.5%, respectively. In group 2, no success occurred. The diameter and length of the stricture, kidney function, hydronephrosis grade, presence of urinary infection at presentation, past CNI or radiotherapy, number of incisions with the cold-knife, and premature appearance of the anastomosis stricture were statistically significant influences on the outcome (P <0.05). Considering only the patients (n = 8) with the most favorable predictive factors (interval to stricture formation 12 months or longer, stricture length 1.5 cm or less, and hydronephrosis grade I-II), the success rate was 100%. No complications were observed. CONCLUSIONS CNI is an effective and minimally invasive treatment for primary UASs, providing durable results compared with other modalities used for endoureterotomy, and should be considered as an initial approach. The selection of patients with the most favorable prognostic factors leads to excellent results. As a secondary procedure, CNI was not successful.


BJUI | 2004

Transurethral electrovaporization vs transurethral resection for symptomatic prostatic obstruction: a meta‐analysis

Vassilis Poulakis; Philipp Dahm; U. Witzsch; Alex J. Sutton; Eduard Becht

To compare the effectiveness and safety of transurethral electrovaporization (TUEVP) and transurethral resection of the prostate (TURP) for symptomatic bladder outlet obstruction secondary to benign prostatic hyperplasia (BPH).


Urology | 2006

Vesicourethral anastomosis during endoscopic extraperitoneal radical prostatectomy: a prospective comparison between the single-knot running and interrupted technique.

Vassilis Poulakis; Konstantinos Skriapas; Rachelle de Vries; Wolfgang Dillenburg; U. Witzsch; Eduard Becht

OBJECTIVES To determine the safety and efficacy of the single-knot running versus interrupted technique for urethrovesical anastomosis during endoscopic extraperitoneal radical prostatectomy. METHODS A total of 250 consecutive patients who underwent endoscopic extraperitoneal radical prostatectomy were prospectively divided into two groups of 125 patients each who underwent urethrovesical anastomosis using the single-knot running technique (group 1) or the interrupted suture technique (group 2). Surgical data, operative time, difficulty scores, extravasation rate, catheterization time, occurrence of anastomotic strictures, and the early and late continence rates were analyzed statistically. RESULTS Regarding the clinical and pathologic findings, extravasation rate, catheterization time, and occurrence of anastomotic strictures, no significant differences were found between the two groups (P >0.05). The strongest independent predictors for extravasation were the integrity of the dorsal wall of the anastomosis and the degree of bladder neck opening (P <0.001). Overall, the continence rate at 3 and 6 months was 76% and 91.5% for group 1 and 77.6% and 93% for group 2, respectively (all P >0.05). The anastomosis technique had no impact on extravasation or continence status (all P >0.05). The only significant differences (P <0.001) in favor of the single-knot technique were the mean operative time and difficulty score (16 versus 24 minutes and 1 versus 3, respectively). CONCLUSIONS Both techniques provide satisfactory and similar functional results. However, because of its simplicity and shorter operative time, the single-knot running technique appears preferable.


BJUI | 2012

Robotic repair of vesicovaginal fistula (VVF)

Rene Sotelo; Vassilis Moros; Rafael Clavijo; Vassilis Poulakis

While worldwide, the predominant cause of VVF is obstructed labour due to poor obstetric care, in obstetrically developed countries this is usually an iatrogenic complication of gynaecological surgery, most commonly abdominal hysterectomy, occurring in one in every 1800 hysterectomies [ 2 – 4 ] . Generally, VVF occurs 1 – 6 weeks after gynaecological or obstetric surgery, while recurrent fi stula can develop within the fi rst 3 months after primary repair [ 2 ] .

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U. Witzsch

Goethe University Frankfurt

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U. Witzsch

Goethe University Frankfurt

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Ashok K. Hemal

Wake Forest Baptist Medical Center

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E. Becht

Goethe University Frankfurt

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