Arpeet Shah

Functional Implications of Renal Tumor Enucleation Relative to Standard Partial Nephrectomy

OBJECTIVE To compare the surgical precision for optimizing nephron-mass preservation of tumor enucleation (TE) vs standard partial nephrectomy (SPN), with primary focus on functional outcomes. TE is presumed to optimize preservation of parenchymal mass and function but this has not yet been rigorously studied and quantified. MATERIALS AND METHODS Robotic partial nephrectomy patients who had appropriate pre- and postoperative studies for analysis of parenchymal mass preservation specific to the operated kidney were included. Computed tomography or magnetic resonance imaging and estimated glomerular filtration rate were required to be <2 months prior and 4-12 months after surgery. Parenchymal mass preservation and surgical precision were estimated for each technique, with precision defined as actual postoperative parenchymal volume or predicted postoperative parenchymal volume, presuming loss of a 5 mm rim of parenchyma associated with tumor excision and reconstruction. RESULTS Analysis included 57 TE and 53 SPN. Median age, body mass index, and tumor size were comparable. Percent parenchymal mass preserved in the operated kidney with TE was 96% (interquartile range [IQR] = 90-100) vs 89% (IQR = 83-96) for SPN (P = .003). Precision of excision or reconstruction was 101% (IQR = 96-105) for TE vs 94% (IQR = 88-100) for SPN (P < .001). On multivariable analysis, only TE correlated with improved surgical precision (coefficient = 6.7, 95% confidence interval = 1.6-11.8, P = .01). Although preservation of global renal function also favored TE, the differences were marginal (96% vs 93%), and statistical significance was not observed (P = .2). CONCLUSION Our analysis, which specifically focuses on the functional implications of TE, demonstrates that TE maximally spares normal parenchyma compared to SPN. Thus far, functional differences remain marginal and not statistically significant. Clinical significance of these findings in various clinical settings will require further investigation.

Rates and Risk Factors for Opioid Dependence and Overdose after Urological Surgery

Purpose: Effective pain management is a critical component of the perioperative process with opioids representing a mainstay of therapy. The opioid epidemic is a growing concern in the United States. The goal of this study was to quantify the risk of opioid dependence or overdose among patients undergoing urological surgery and to identify risk factors of opioid dependence or overdose. Materials and Methods: We retrospectively reviewed data on urological surgery from 2007 to 2011. Data sources included the HCUP (Healthcare Cost and Utilization Project) inpatient, ambulatory surgery and emergency department data sets. Outcomes of postoperative opioid dependence and overdose were identified by previously validated ICD‐9 codes. Multivariable logistic regression adjusted for surgical procedure was performed to identify predictors of opioid dependence or overdose following urological surgery. Results: Overall 675,527 patients underwent urological surgery, of whom 0.09% were diagnosed with opioid dependence or overdose. Patients in whom opioid dependence or overdose developed were younger (median age 51 vs 62 years), carried nonprivate insurance (69.6% vs 66%), underwent an inpatient procedure (81.0% vs 42.4%) and had a longer length of stay (median 3 vs 0 days) and a history of depression (14.4% vs 3.4%) or chronic obstructive pulmonary disease (20.3% vs 8.9%, all p <0.001). On adjusted multivariable analysis these factors remained independent risk factors for opioid dependence or overdose. Conclusions: Postoperative opioid dependence or overdose affects 1 of 1,111 urological surgery patients. Risk factors for opioid dependence or overdose included younger age, inpatient surgery and increasing hospitalization duration, baseline depression, tobacco use and chronic obstructive pulmonary disease as well as insurance provider, including Medicaid, Medicare (age less than 65 years) and noninsured status.

Functional Comparison of Renal Tumor Enucleation Versus Standard Partial Nephrectomy

BACKGROUND Tumor enucleation (TE) optimizes parenchymal preservation and could yield better function than standard partial nephrectomy (SPN), although data on this are conflicting. OBJECTIVE To compare functional outcomes for TE and SPN strategies. DESIGN, SETTING, AND PARTICIPANTS Patients managed with partial nephrectomy (PN) with necessary data for analysis of preservation of ipsilateral parenchymal mass (IPM) and global glomerular filtration rate (GFR) from two centers were included. All studies were required <2 mo before and 3-12 mo after surgery. Patients with a solitary kidney or multifocal tumors were excluded. INTERVENTION Partial nephrectomy. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS Vascularized IPM was estimated from contrast-enhanced CT scans preoperatively and postoperatively. Serum creatinine-based estimates of global GFR were also obtained in the same timeframes. Univariable and multivariable linear regression evaluated factors associated with new-baseline global GFR. RESULTS/LIMITATIONS Analysis included 71 TE and 373 SPN cases. The median preoperative global GFR was comparable for TE and SPN (75 vs 78ml/min/1.73m2; p=0.6). The median tumor size was 3.0cm for TE and 3.3cm for SPN (p=0.03). The median RENAL score was 7 in both cohorts. For TE, warm ischemia and zero ischemia were used in 51% and 49% of cases, respectively. For SPN, warm ischemia and cold ischemia were used in 72% and 28% of patients, respectively. Capsular closure was performed in 46% of TE and 100% of SPN cases (p<0.001). Positive margins were found in 8.5% of TE and 4.8% of SPN patients (p=0.2). The median vascularized IPM preserved was 95% (interquartile range [IQR] 91-100%) for TE and 84% (IQR 76-92%) for SPN (p<0.001). The median global GFR preserved was 101%(IQR 93-111%) and 89% (IQR 81-96%) for TE and SPN, respectively (p<0.001). On multivariable analysis, resection strategy, preoperative GFR, and vascularized IPM preserved were all significantly associated (p<0.001) with new-baseline global GFR. Limitations include the retrospective design and the lack of resection outcome data. CONCLUSIONS Our analysis suggests that TE has potential for maximum IPM preservation compared to SPN and may provide optimized functional recovery. Further investigation will be required to evaluate the clinical significance of these findings. PATIENT SUMMARY Tumor enucleation for kidney cancer involves dissection along the tumor capsule and optimally preserves normal kidney tissue, which may lead to better functional recovery. The importance of this approach in various clinical settings will require further investigation.

Cost Analysis of Metallic Stents for Chronic Ureteral Obstruction: A Multicenter Study

Introduction: Metallic and polymer ureteral stents are used to manage chronic ureteral obstruction. In general, metallic stents are more costly than polymer stents but they are changed less frequently. We examined the overall costs of using these stent types at 2 institutions. Methods: We identified all patients in whom a metallic stent was placed at 2 academic institutions between July 2007 and July 2013. We calculated the average time to stent exchange or failure and the overall cost of metallic and polymer stent use. Costs included those associated with materials, operating room services, anesthesia and other expenses. Results: We identified 86 patients in whom a total of 230 metallic stents were placed. Time to stent failure or exchange of a metallic stent was 7.4 months. The per unit cost of a polymer stent and a metallic stent was

Complications of Recognized and Unrecognized Iatrogenic Ureteral Injury at Time of Hysterectomy: A Population Based Analysis

121 and

Adhesive Bowel Obstruction Following Urologic Surgery: Improved Outcomes with Early Intervention

887, respectively. The average annual cost of unilateral and bilateral metallic stents was

MP41-10 RENAL TUMOR ENUCLEATION MAXIMALLY PRESERVES RENAL PARENCHYMAL VOLUME COMPARED TO STANDARD PARTIAL NEPHRECTOMY

7,859.43 and

MP42-02 TUMOR ENUCLEATION: FUNCTIONAL COMPARISON WITH STANDARD PARTIAL NEPHRECTOMY

9,296.37, respectively. For a unilateral polymer stent that was changed every 3 months the yearly cost was

MP13-02 IS POSTOPERATIVE URINARY RETENTION AN INDEPENDENT PREDICTOR OF LONG-TERM FUTURE BLADDER OUTLET PROCEDURE IN MEN?

16,342. For bilateral polymer stents that were changed every 3 months the cost was

MP37-10 ADHESIVE BOWEL OBSTRUCTION FOLLOWING UROLOGIC SURGERY: IMPROVED OUTCOMES WITH EARLY INTERVENTION

16,826 per year. If unilateral and bilateral polymer stents were changed every 6 months, the costs were