Trushar Patel

Clinical Outcomes After Radical Prostatectomy in Diabetic Patients Treated With Metformin

OBJECTIVES To investigate the relationship between diabetes and metformin use with outcomes after radical prostatectomy (RP) for clinically localized cancer. METHODS A total of 112 diabetic metformin users and 98 diabetic non-metformin users treated with RP from 1990 to 2009 were identified. Nondiabetic controls were match using their 5-year risk of biochemical recurrence (BCR) as calculated by the preoperative Kattan nomogram. RESULTS A total of 616 patients were evaluated in this study. There was no significant difference between nondiabetic and diabetic patients, including metformin users, with respect to age, clinical stage, preoperative prostate-specific antigen (PSA) score, pathologic Gleason score, and pathologic stage. Diabetic patients, including metformin users, were more likely to be of African American or Hispanic background than were nondiabetic controls (P = .001). The estimated 5-year BCR-free survival was 75.0% for nondiabetic patients, compared with 66.1% for metformin users and 59.3% for diabetic non-metformin users (P = .004). In multivariate analysis, metformin use was not significantly associated with risk of BCR (HR = 0.94; 95% CI = 0.6-1.5, P = .817). However, being diabetic, regardless of metformin use, resulted in a 55% increase in risk of BCR (HR = 1.55; 95% CI = 1.03-2.33, P = .034). CONCLUSIONS Diabetes, regardless of metformin use, was significantly associated with an increased likelihood of BCR after RP. Metformin use did not prove to be of any benefit. These observations underscore the importance for further studies evaluating the metabolic pathways that affect prostate cancer biology.

Skin to Stone Distance Is an Independent Predictor of Stone-Free Status Following Shockwave Lithotripsy

INTRODUCTION In recent years several new parameters such as Hounsefield unit density and skin to stone distance (SSD) have been determined to correlate with successful extracorporeal shockwave lithotripsy (SWL). SSD has been shown to independently predict successful SWL for lower pole calculi. The objective of this study was to determine which stone characteristics on noncontrast computed tomography (NCCT), including SSD, independently predict for SWL success regardless of stone location within the kidney. MATERIALS AND METHODS A retrospective review of all 1282 SWL procedures between 2004 and 2007 at a single institution revealed 83 patients meeting inclusion criteria for current study. All patients were treated using a single electromagnetic lithotriptor (DoLi 50; Dornier Medical Systems, Marrieta, GA) with a single technician. Stone-free (SF) status was determined by NCCT or abdominal plain film radiographs at 6 weeks post-SWL. Logistic regression analysis was computed to assess SF rates using SSD, stone size, location, and Hounsefield unit density as predictors. RESULT Of the 83 patients, 51 were SF and 32 had residual stones at a mean follow-up of 2.3 months. The mean SSD in the SF group was 83.3 +/- 21.9 mm in comparison to those in the residual stone group who had a mean SSD of 107.7 +/- 28.9 mm (p < or = 0.05). Multivariate logistic regression analysis revealed that SSD was the only significant independent predictor of treatment outcome. CONCLUSION SSD is an easily measured parameter on NCCT that independently correlates with SWL efficacy in treating stones in all locations.

Intravesical Delivery of Rapamycin Suppresses Tumorigenesis in a Mouse Model of Progressive Bladder Cancer

Early-stage bladder cancer occurs as two distinct forms: namely, low-grade superficial disease and high-grade carcinoma in situ (CIS), which is the major precursor of muscle-invasive bladder cancer. Although the low-grade form is readily treatable, few, if any, effective treatments are currently available for preventing progression of nonmuscle-invasive CIS to invasive bladder cancer. Based on our previous findings that the mammalian target of Rapamycin (mTOR) signaling pathway is activated in muscle-invasive bladder cancer, but not superficial disease, we reasoned that suppression of this pathway might block cancer progression. To test this idea, we performed in vivo preclinical studies using a genetically engineered mouse model that we now show recapitulates progression from nonmuscle-invasive CIS to muscle-invasive bladder tumors. We find that delivery of Rapamycin, an mTOR inhibitor, subsequent to the occurrence of CIS effectively prevents progression to invasive bladder cancer. Furthermore, we show that intravesical delivery of Rapamycin directly into the bladder lumen is highly effective for suppressing bladder tumorigenesis. Thus, our findings show the potential therapeutic benefit of inhibiting mTOR signaling for treatment of patients at high risk of developing invasive bladder cancer. More broadly, our findings support a more widespread use of intravesical delivery of therapeutic agents for treatment of high-risk bladder cancer patients, and provide a mouse model for effective preclinical testing of potential novel agents.

Prospective Randomized Evaluation of Periureteral Botulinum Toxin Type A Injection for Ureteral Stent Pain Reduction

PURPOSE The use of ureteral stents for ureteral obstruction and after ureteroscopy can result in substantial deterioration in patient quality of life due to pain, frequency and urgency. We postulated that many stent related symptoms may be related to detrusor muscle spasm in and around the intramural ureter, and evaluated the effect of botulinum toxin type A (Botox) in patients with indwelling stents after ureteroscopy. MATERIALS AND METHODS A total of 51 patients between December 2007 and March 2009 were enrolled in an institutional review board approved, prospective, randomized, single-blind study comparing botulinum toxin type A injection at a concentration of 10 U/ml to 3 locations around the ureteral orifice (30) vs no injection after unilateral ureteral stent insertion (21). Pain and urinary symptoms after stent placement were evaluated through the Ureteral Stent Symptom Questionnaire, which was completed on postoperative day 7. In addition, patients were required to maintain a log of narcotic use after stent placement until removal. The Wilcoxon rank sum and Fisher exact tests were used for nonparametric and categorical data, respectively, with p <or=0.05 considered significant. RESULTS No complications or adverse events occurred in this study. There was a significant decrease in the reported postoperative pain score between the botulinum toxin type A and control group at 3.4 vs 6.0 (p = 0.02). Postoperative narcotic use was also significantly less in the botulinum toxin type A group at 7.7 pills during an average of 2.7 days vs 24.7 in an average of 7.0 days in control patients (p = 0.03). With respect to postoperative lower urinary tract symptoms there was no significant difference between cohorts using the individual index scores within the Ureteral Stent Symptom Questionnaire. Stent related emergency room visits were reported by 1 patient treated in the botulinum toxin type A group vs 2 in the control group. CONCLUSIONS Periureteral botulinum toxin type A injection improves ureteral stent tolerability by significantly decreasing postoperative pain and narcotic requirements. Improvement in irritative symptoms was not observed.

Immediate radical cystectomy vs conservative management for high grade cT1 bladder cancer: is there a survival difference?

Study Type – Aetiology (individual cohort)

Single Institutional Experience with Nephron-sparing Surgery for Pathologic Stage T3bNxM0 Renal Cell Carcinoma Confined to the Renal Vein

OBJECTIVE To assess our institutions experience with the management of pathologic stage T3bNxM0 renal cell carcinoma with tumor thrombus confined to the renal vein treated with nephron-sparing surgery (NSS). METHODS Of the 492 patients who have undergone NSS at Columbia University from 1998 to 2009, 8 patients were found to have stage T3bNxM0 renal cell carcinoma (RCC) on final pathology. Records were reviewed for indication for NSS, imaging studies, perioperative management, surgical details, pathology, and both functional and disease-specific outcomes. Postoperative renal function was estimated by most recent glomerular filtration rate using Modification of Diet in Renal Disease formula. Recurrence of RCC was monitored using serial axial imaging. RESULTS The 8 patients were presumed to be clinical stage T1aN0M0 RCC before surgery; however, tumor thrombus was identified in the renal vein intraoperatively and on final pathology in 4, and 4 cases, respectively, corresponding to stage T3bNxM0 RCC by current American Joint Committee on Cancer-Tumor-Necrosis-Metastasis 2002 criteria. After a median follow-up of 19.8 months, the patients experienced a mean decrease in estimated glomerular filtration rate of 27.1%. One patient developed new-onset renal failure, defined as an estimated glomerular filtration rate below 30 mL/min/1.73 m(2). Clean surgical margins were obtained in 7 patients. Carcinoma was identified at the parenchymal margin in 1 patient. No patients have evidence of recurrence of RCC by serial axial imaging. CONCLUSIONS NSS does not seem to have had a negative impact on a small series of patients with pathologic stage T3bNxM0 RCC limited to the renal vein and may be a feasible option when the clinical situation indicates a need for preservation of renal function.

Heparin prophylaxis and the risk of venous thromboembolism after robotic‐assisted laparoscopic prostatectomy

Study Type – Therapy (case series)

Efficacy of endopyelotomy in patients with secondary ureteropelvic junction obstruction.

BACKGROUND AND PURPOSE Few studies have focused on secondary ureteropelvic junction obstruction (UPJO) as a disease entity. This study was designed to elucidate the etiology of secondary UPJO and to assess the success rate of endopyelotomy in these cases. PATIENTS AND METHODS A retrospective review of all patients who underwent an endopyelotomy by a single surgeon from May 1997 to September 2009 was conducted. Secondary UPJO was defined anastomotic strictures after dismembered pyeloplasty or as de novo formation after renal surgery. Success of the procedure was defined as both radiographic and symptomatic resolution of obstruction. RESULTS Of 157 endopyelotomies performed, 41 patients were considered to have secondary UPJO. Of these 41, previous open or laparoscopic pyeloplasties had failed in 14. Twenty classified as iatrogenic from previous renal surgeries: 10 open, 8 percutaneous, and 2 ureteroscopic. Two cases of secondary UPJO were attributed to strictures that were secondary to impacted stones in the past. The remaining five patients were considered to have idiopathic secondary UPJO and had previous normal imaging studies demonstrating absence of hydronephrosis before development of UJPO. The surgical success rate was 83.5% (35/41) for endopyelotomy in these cases. Seventy-five percent (3/4) of endopyelotomies in children ≤5 years old failed. CONCLUSIONS With proper selection, endopyelotomy for secondary UPJO in the adult population was found to be successful and should be considered before more invasive therapy. Success in the pediatric population was poor in this limited evaluation.

The da vinci robot system eliminates multispecialty surgical trainees' hand dominance in open and robotic surgical settings.

Background and Objectives: Handedness, or the inherent dominance of one hands dexterity over the others, is a factor in open surgery but has an unknown importance in robot-assisted surgery. We sought to examine whether the robotic surgery platform could eliminate the effect of inherent hand preference. Methods: Residents from the Urology and Obstetrics/Gynecology departments were enrolled. Ambidextrous and left-handed subjects were excluded. After completing a questionnaire, subjects performed three tasks modified from the Fundamentals of Laparoscopic Surgery curriculum. Tasks were performed by hand and then with the da Vinci robotic surgical system (Intuitive Surgical, Sunnyvale, California). Participants were randomized to begin with using either the left or the right hand, and then switch. Left:right ratios were calculated from scores based on time to task completion. Linear regression analysis was used to determine the significance of the impact of surgical technique on hand dominance. Results: Ten subjects were enrolled. The mean difference in raw score performance between the right and left hands was 12.5 seconds for open tasks and 8 seconds for robotic tasks (P < .05). Overall left-right ratios were found to be 1.45 versus 1.12 for the open and robot tasks, respectively (P < .05). Handedness significantly differed between robotic and open approaches for raw time scores (P < .0001) and left-right ratio (P = .03) when controlling for the prior tasks completed, starting hand, prior robotic experience, and comfort level. These findings remain to be validated in larger cohorts. Conclusion: The robotic technique reduces hand dominance in surgical trainees across all task domains. This finding contributes to the known advantages of robotic surgery.

A Pilot Study of Laparoscopic Doppler Ultrasound Probe to Map Arterial Vascular Flow within the Neurovascular Bundle during Robot-Assisted Radical Prostatectomy

Purpose. To report on the feasibility of a new Laparoscopic Doppler ultrasound (LDU) technology to aid in identifying and preserving arterial blood flow within the neurovascular bundle (NVB) during robotic prostatectomy (RARP). Materials and Methods. Nine patients with normal preoperative potency and scheduled for a bilateral nerve-sparing procedure were prospectively enrolled. LDU was used to measure arterial flow at 6 anatomic locations alongside the prostate, and signal intensity was evaluated by 4 independent reviewers. Measurements were made before and after NVB dissection. Modifications in nerve-sparing procedure due to LDU use were recorded. Postoperative erectile function was assessed. Fleiss Kappa statistic was used to evaluate inter-rater agreement for each of the 12 measurements. Results. Analysis of Doppler signal intensity showed maintenance of flow in 80% of points assessed, a decrease in 16%, and an increase in 4%. Plane of NVB dissection was altered in 5 patients (56%) on the left and in 4 patients (44%) on the right. There was good inter-rater reliability for the 4 reviewers. Use of the probe did not significantly increase operative time or result in any complications. Seven (78%) patients had recovery of erections at time of the 8-month follow-up visit. Conclusions. LDU is a safe, easy to use, and effective method to identify local vasculature and anatomic landmarks during RARP, and can potentially be used to achieve greater nerve preservation.