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Dive into the research topics where Michael A. Liss is active.

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Featured researches published by Michael A. Liss.


The Journal of Urology | 2011

Prevalence and Significance of Fluoroquinolone Resistant Escherichia coli in Patients Undergoing Transrectal Ultrasound Guided Prostate Needle Biopsy

Michael A. Liss; Alexandra Chang; Rosanne Santos; Amy Nakama-Peeples; Ellena M. Peterson; Kathryn Osann; John Billimek; Richard J. Szabo; Atreya Dash

PURPOSE We estimated the prevalence of fluoroquinolone resistant Escherichia coli in patients undergoing repeat transrectal ultrasound guided prostate needle biopsy and identified high risk groups. MATERIALS AND METHODS From January 2009 to March 2010 rectal swabs of 136 men from 3 institutions undergoing transrectal ultrasound guided prostate needle biopsy were obtained. There were 33 men with no previous biopsy who served as the controls. Participants completed questionnaires and rectal swab culture was obtained just before performing the prostate biopsy. Selective media was used to specifically isolate fluoroquinolone resistant E. coli and sensitivities were obtained. The patients were contacted via telephone 7 days after the procedure for a followup questionnaire. RESULTS A total of 30 patients had cultures positive for fluoroquinolone resistant bacteria for an overall rate of 22% (95% CI 15, 29). Patients with diabetes and Asian ethnicity had higher risks of resistant rectal flora colonization (OR 2.3 and 2.8, respectively). However, differences did not reach statistical significance (p = 0.09 and p = 0.08, respectively). Patients with no prior biopsy had a positive rate of 15% (5 of 33) compared to 24% (25 of 103) in those with 1 or more prior biopsies (OR 1.8, p = 0.27). Five patients (3.6%) had post-biopsy fever while only 1 of those patients had a positive rectal swab. CONCLUSIONS Using selective media to isolate fluoroquinolone resistant E. coli from the rectum before transrectal ultrasound guided prostate biopsy, we isolated organisms in 22% of patients with a wide resistance pattern. This protocol may be used to provide information regarding targeted antibiotic prophylaxis before transrectal prostate biopsies.


The Journal of Urology | 2010

Continence Definition After Radical Prostatectomy Using Urinary Quality of Life: Evaluation of Patient Reported Validated Questionnaires

Michael A. Liss; Kathryn Osann; Noah Canvasser; William Chu; Alexandra Chang; Jennifer M Gan; Roger Li; Rosanne Santos; Douglas Skarecky; David S. Finley; Thomas E. Ahlering

PURPOSE After radical prostatectomy continence is commonly defined as no pads except a security pad or 0 to 1 pad. We evaluated the association of pad status and urinary quality of life to determine whether security and 1 pad status differ from pad-free status to better define 0 pads as the post-prostatectomy standard. MATERIALS AND METHODS A total of 500 consecutive men underwent robot assisted radical prostatectomy from October 2003 to July 2007. Data were collected prospectively and entered into an electronic database. Postoperatively men completed self-administered validated questionnaires including questions on 1) daily pad use (0, security, 1, or 2 or more), 2) urine leakage (daily, about once weekly, less than once weekly or not at all), 3) urinary control (none, frequent dribbling, occasional dribbling or total control), 4) American Urological Association symptom score and 5) urinary quality of life. RESULTS Postoperatively men who indicated 0 pad use had a mean +/- SE symptom score of 5.8 +/- 0.3 and pleased quality of life (1.16 +/- 0.08). In contrast, men with a security pad and 1 pad had a symptom score of 7.6 +/- 0.7 and 9.2 +/- 0.6 but mixed quality of life (2.78 +/- 0.18 and 3.41 +/- 0.15, respectively, p <0.0005). CONCLUSIONS Results show a significant decrease in quality of life between no pads (1.16 or pleased), a security pad and 0 or 1 pad (2.78 and 3.41 or mixed, respectively). Findings do not support defining continence with a security pad or 0 to 1 pad. Continence should be strictly defined as 0 pads.


The Journal of Urology | 2011

Positive surgical margins after robotic assisted radical prostatectomy: A multi-institutional study

Vipul R. Patel; Rafael F. Coelho; Bernardo Rocco; Marcelo A. Orvieto; Ananthakrishnan Sivaraman; Kenneth J. Palmer; Darien Kameh; Luigi Santoro; Geoff Coughlin; Michael A. Liss; Wooju Jeong; John B. Malcolm; Joshua M. Stern; Saurabh Sharma; Kevin C. Zorn; Sergey Shikanov; Arieh L. Shalhav; Gregory P. Zagaja; Thomas E. Ahlering; Koon Ho Rha; David M. Albala; Michael D. Fabrizio; David I. Lee; Sanket Chauhan

PURPOSE Positive surgical margins are an independent predictive factor for biochemical recurrence after radical prostatectomy. We analyzed the incidence of and associative factors for positive surgical margins in a multi-institutional series of 8,418 robotic assisted radical prostatectomies. MATERIALS AND METHODS We analyzed the records of 8,418 patients who underwent robotic assisted radical prostatectomy at 7 institutions. Of the patients 323 had missing data on margin status. Positive surgical margins were categorized into 4 groups, including apex, bladder neck, posterolateral and multifocal. The records of 6,169 patients were available for multivariate analysis. The variables entered into the logistic regression models were age, body mass index, preoperative prostate specific antigen, biopsy Gleason score, prostate weight and pathological stage. A second model was built to identify predictive factors for positive surgical margins in the subset of patients with organ confined disease (pT2). RESULTS The overall positive surgical margin rate was 15.7% (1,272 of 8,095 patients). The positive surgical margin rate for pT2 and pT3 disease was 9.45% and 37.2%, respectively. On multivariate analysis pathological stage (pT2 vs pT3 OR 4.588, p<0.001) and preoperative prostate specific antigen (4 or less vs greater than 10 ng/ml OR 2.918, p<0.001) were the most important independent predictive factors for positive surgical margins after robotic assisted radical prostatectomy. Increasing prostate weight was associated with a lower risk of positive surgical margins after robotic assisted radical prostatectomy (OR 0.984, p<0.001) and a higher body mass index was associated with a higher risk of positive surgical margins (OR 1.032, p<0.001). For organ confined disease preoperative prostate specific antigen was the most important factor that independently correlated with positive surgical margins (4 or less vs greater than 10 ng/ml OR 3.8, p<0.001). CONCLUSIONS The prostatic apex followed by a posterolateral site was the most common location of positive surgical margins after robotic assisted radical prostatectomy. Factors that correlated with cancer aggressiveness, such as pathological stage and preoperative prostate specific antigen, were the most important factors independently associated with an increased risk of positive surgical margins after robotic assisted radical prostatectomy.


Journal of Endourology | 2012

Validation, Correlation, and Comparison of the da Vinci Trainer™ and the da Vinci Surgical Skills Simulator™ Using the Mimic™ Software for Urologic Robotic Surgical Education

Michael A. Liss; Corollos S. Abdelshehid; Stephen Quach; Achim Lusch; Joseph A. Graversen; Jaime Landman; Elspeth M. McDougall

PURPOSE Virtual reality simulators with self-assessment software may assist novice robotic surgeons to augment direct proctoring in robotic surgical skill acquisition. We compare and correlate the da Vinci Trainer™ (dVT) and da Vinci Surgical Skills Simulators (dVSSS) in subjects with varying robotic experience. MATERIALS AND METHODS Students, urology residents, fellows, and practicing urologists with varying robotic experience were enrolled after local institutional review board approval. Three virtual reality tasks were preformed in sequential order (pegboard 1, pegboard 2, and tubes)-initially on the dVSSS and then on the dVT. The Mimic™ software used on both systems provides raw values and percent scores that were used in statistical evaluation. Statistical analysis was performed with the two-tailed independent t-test, analysis of variance, Tukey, and the Pearson rank correlation coefficient where appropriate. RESULTS Thirty-two participants were recruited for this study and separated into five groups based on robotic surgery experience. In regards to construct validity, both simulators were able to differentiate differences among the five robotic surgery experience groups in the tubes suturing task (p≤0.00). Sixty-seven percent (4/6) robotic experts thought that surgical simulation should be implemented in residency training. The overall cohort considered both platforms easy to learn and use. CONCLUSIONS Although performance scores were less in the dVT compared with the dVSSS, both simulators demonstrate good content and construct validity. The simulators appear to be equivalent for assessing surgeon proficiency and either can be used for robotic skills training with self-assessment feedback.


BJUI | 2014

Survival outcomes after radical and partial nephrectomy for clinical T2 renal tumours categorised by R.E.N.A.L. nephrometry score

Ryan P. Kopp; Reza Mehrazin; Kerrin L. Palazzi; Michael A. Liss; Ramzi Jabaji; Hossein Mirheydar; Hak Jong Lee; Nishant Patel; Fuad Elkhoury; Anthony L. Patterson; Ithaar H. Derweesh

We evaluated survival outcomes of partial nephrectomy (PN) and radical nephrectomy (RN) for clinical T2 renal masses (cT2RM) controlling for R.E.N.A.L. nephrometry score.


Urology | 2009

Sepsis Due to Fluoroquinolone-resistant Escherichia coli After Transrectal Ultrasound-guided Prostate Needle Biopsy

Jennifer L. Young; Michael A. Liss; Richard J. Szabo

OBJECTIVES To report a series of patients with sepsis due to fluoroquinolone-resistant Escherichia coli after prostate needle biopsy across 4 hospitals in southern California. METHODS Five patients presented with fever and blood cultures positive for fluoroquinolone-resistant E. coli after prostate needle biopsy with pre-procedure fluoroquinolone antimicrobial prophylaxis. The cases are described and the published data reviewed. RESULTS Of the 5 patients, 1 was treated at Hoag Memorial Hospital in 2008, 2 were treated at the Long Beach Veterans Affairs Medical Center, 1 was treated at Kaiser Permanente Hospital in 2007, and 1 presented to University of California, Irvine, Medical Center in 2006. All patients received an oral fluoroquinolone antibiotic the morning of or 1 hour before biopsy. Of the 5 patients, 4 also received gentamicin intramuscularly before biopsy. CONCLUSIONS The estimated incidence of sepsis was 0.1%-0.9%, assuming patients reported to the hospital at which the biopsy was performed. From a review of the published data, we recommend a fluoroquinolone antibiotic before and after biopsy for < or =24 hours. From our findings, if the patient has taken a fluoroquinolone antibiotic in the past 8 months, a second- or third-generation cephalosporin should be used or an aminoglycoside (1.5-2 mg/kg intramuscularly) with metronidazole or clindamycin. A carbapenem should be substituted if the patient has a history of infections with extended-spectrum beta-lactamase producers. Cases of fluoroquinolone-resistant E. coli should be tracked in a nationalized database.


BJUI | 2008

Positive surgical margins during robotic radical prostatectomy : a contemporary analysis of risk factors

Michael A. Liss; Kathryn Osann; David K. Ornstein

To determine the risk factors (clinical, pathological and technical) for positive surgical margins (PSMs) after robotically assisted radical prostatectomy (RARP), as a PSM is associated with an increased risk of biochemical recurrence and often responsible for significant patient anxiety.


Journal of Translational Medicine | 2014

Tumor infiltrating B-cells are increased in prostate cancer tissue

Jason Woo; Michael A. Liss; Michelle Muldong; Kerrin L. Palazzi; Amy Strasner; Massimo Ammirante; Nissi M. Varki; Ahmed Shabaik; Stephen B. Howell; Christopher J. Kane; Michael Karin; Christina Jamieson

BackgroundThe presence of increased B-cell tumor infiltrating lymphocytes (TILs) was seen in mouse prostate cancer (PCa) but has not been fully documented in human PCa. We, therefore, investigated the density of infiltrating B cells within human PCa utilizing a quantitative computational method.MethodsArchived radical prostatectomy specimens from 53 patients with known clinical outcome and D’Amico risk category were obtained and immunohistochemically (IHC) stained for the B cell marker, CD20. Slides were reviewed by a genitourinary pathologist who manually delineated the tumoral regions of PCa. Slides were digitally scanned and a computer algorithm quantified the area of CD20 stained B-cells as a measure of B cell density within the outlined regions of prostate cancer (intra-tumoral region), versus extra-tumoral prostate tissue. Correlations were analyzed between B-cell density and demographic and clinical variables, including D’Amico risk groups and disease recurrence.ResultsFor the entire cohort, the mean intra-tumoral B cell density was higher (3.22 SE = 0.29) than in the extra-tumoral region of each prostatectomy section (2.24, SE = 0.19) (paired t test; P < 0.001). When analyzed according to D’Amico risk group, the intra-tumoral B cell infiltration in low risk (0.0377 vs. 0.0246; p = 0.151) and intermediate risk (0.0260 vs. 0.0214; p = 0.579) patient prostatectomy specimens did not show significantly more B-cells within the PCa tumor. However, patient specimens from the high-risk group (0.0301 vs. 0.0197; p < 0.001) and from those who eventually had PCa recurrence or progression (0.0343 vs. 0.0246; p = 0.019) did show significantly more intra-tumoral CD20+ B-cell staining. Extent of B-cell infiltration in the prostatectomy specimens did not correlate with any other clinical parameters.ConclusionsOur study shows that higher B-cell infiltration was present within the intra-tumoral PCa regions compared to the extra-tumoral benign prostate tissue regions in prostatectomy sections. For this study we developed a new method to measure B-cells using computer-assisted digitized image analysis. Accurate, consistent quantitation of B-cells in prostatectomy specimens is essential for future clinical trials evaluating the effect of B cell ablating antibodies. The interaction of B-cells and PCa may serve as the basis for new therapeutic targets.


Journal of Endourology | 2014

Evaluation of the impact of three-dimensional vision on laparoscopic performance.

Achim Lusch; Philip Bucur; Ashleigh Menhadji; Zhamshid Okhunov; Michael A. Liss; Alberto Perez-Lanzac; Elspeth M. McDougall; Jaime Landman

INTRODUCTION Recent technological advancements have led to the introduction of new three-dimensional (3D) cameras in laparoscopic surgery. The 3D view has been touted as useful during robotic surgery, however, there has been limited investigation into the utility of 3D in laparoscopy. MATERIALS AND METHODS We performed a prospective, randomized crossover trial comparing a 0° 3D camera with a conventional 0° two-dimensional (2D) camera using a high definition monitor (Karl Storz, Tuttlingen, Germany). All participants completed six standardized basic skills tasks. Quality testing scores were measured by the number of drops, grasping attempts, and precision of needle entry and exiting. Additionally, resolution, color distribution, depth of field and distortion were measured using optical test targets. RESULTS In this pilot study, we evaluated 10 medical students, 7 residents, and 7 expert surgeons. There was a significant difference in the performance in all the six skill tasks, for the three levels of surgical expertise and training levels in 2D vs 3D except for the cut the line quality score and the peg transfer quality score. Adjusting for the training level, 3D camera image results were superior for the number of rings left (p=0.041), ring transfer quality score (p=0.046), thread the rings (no. of rings) (p=0.0004), and thread the rings quality score (p=0.0002). The 3D camera image was also superior for knot tying (quality score) (p=0.004), peg transfer (time in seconds) (p=0.047), peg transfer pegs left (p=0.012), and for peg transfer quality score (p=0.001). The 3D camera system showed significantly less distortion (p=0.0008), a higher depth of field (p=0.0004) compared with the 2D camera system. CONCLUSION 3D laparoscopic camera equipment results in a significant improvement in depth perception, spatial location, and precision of surgical performance compared with the conventional 2D camera equipment. With this improved quality of vision, even expert laparoscopic surgeons may benefit from 3D imaging.


European Urology | 2013

Laparoendoscopic Single-site Partial Nephrectomy: A Multi- institutional Outcome Analysis

Francesco Greco; Riccardo Autorino; Koon Ho Rha; Ithaar H. Derweesh; Luca Cindolo; Lee Richstone; Thomas R. W. Herrmann; Evangelos Liatsikos; Yinghao Sun; Caterina Fanizza; Udo Nagele; J.-U. Stolzenburg; Soroush Rais-Bahrami; Michael A. Liss; Luigi Schips; Ahmad Kassab; Lin-hui Wang; Panagiotis Kallidonis; Zhenjie Wu; Shin Tae Young; Nasreldin Mohammed; Georges Pascal Haber; Christopher Springer; Paolo Fornara; Jihad H. Kaouk

BACKGROUND Laparoendoscopic single-site surgery (LESS) has been developed in an attempt to further reduce the surgical trauma associated with conventional laparoscopy. Partial nephrectomy (PN) represents a challenging indication for LESS. OBJECTIVE To report a large multi-institutional series of LESS-PN and to analyze the predictors of outcomes after LESS-PN. DESIGN, SETTING, AND PARTICIPANTS Consecutive cases of LESS-PN done between November 2007 and March 2012 at 11 participating institutions were included in this retrospective analysis. INTERVENTION Each group performed LESS-PN according to its own protocols, entry criteria, and techniques. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS Demographic data, main perioperative outcome parameters, and perioperative complications were gathered and analyzed. A multivariable analysis was used to assess the factors predicting a short (≤ 20 min) warm ischemia time (WIT), the occurrence of postoperative complication of any grade, and a favorable outcome, arbitrarily defined as a combination of the following events: short WIT plus no perioperative complications plus negative surgical margins plus no conversion to open surgery or standard laparoscopy. RESULTS AND LIMITATIONS A total of 190 cases were included in this analysis. Mean renal tumor size was 2.6, and PADUA score 7.2. Median operative time was 170 min, with median estimated blood loss (EBL) of 150 ml. A clampless technique was adopted in 70 cases (36.8%), and the median WIT was 16.5 min. PADUA score independently predicted length of WIT (low vs high score: odds ratio [OR]: 5.11 [95% confidence interval (CI), 1.50-17.41]; p=0.009; intermediate vs high score: OR: 5.13 [95% CI, 1.56-16.88]; p=0.007). The overall postoperative complication rate was 14.7%. The adoption of a robotic LESS technique versus conventional LESS (OR: 20.92 [95% CI, 2.66-164.64]; p=0.003) and the occurrence of lower (≤ 250 ml) EBL (OR: 3.60 [95% CI, 1.35-9.56]; p=0.010) were found to be independent predictors of no postoperative complications of any grade. A favorable outcome was obtained in 83 cases (43.68%). On multivariate analysis, the only predictive factor of a favorable outcome was the PADUA score (low vs high score: OR: 4.99 [95% CI, 1.98-12.59]; p<0.001). Limitations of the study were the retrospective design and different selection criteria for the participating centers. CONCLUSIONS LESS-PN can be safely and effectively performed by experienced hands, given a high likelihood of a single additional port. Anatomic tumor characteristics as determined by the PADUA score are independent predictors of a favorable surgical outcome. Thus patients presenting tumors with low PADUA scores represent the best candidates for LESS-PN. The application of a robotic platform is likely to reduce the overall risk of postoperative complications.

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Reza Mehrazin

Icahn School of Medicine at Mount Sinai

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Anthony L. Patterson

University of Tennessee Health Science Center

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Ryan P. Kopp

University of California

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Hak Jong Lee

Seoul National University Bundang Hospital

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Ramzi Jabaji

University of California

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