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Purpose: Current radio frequency ablation series do not distinguish renal cell carcinoma subtypes when reporting oncologic efficacy. Papillary neoplasms may be more amenable to radio frequency ablation than clear cell carcinoma because they are less vascular, which may limit heat energy loss. We report the long-term outcomes of patients treated with radio frequency ablation for small renal masses by renal cell carcinoma subtype., Materials and Methods: The records of patients undergoing radio frequency ablation for small renal masses (cT1a) at 2 institutions from March 2007 to July 2012 were retrospectively reviewed. Patients were included in analysis if they had biopsy confirmed clear cell or papillary renal cell carcinoma histology. Patients had at least 1 contrast enhanced cross-sectional image following radio frequency ablation. Demographic data between tumor subtypes were compared using the paired t-test. Oncologic outcomes were determined by Kaplan-Meier survival analysis and survivor curves were compared with the log rank test., Results: A total of 229 patients met study inclusion criteria. There were 181 clear cell tumors and 48 papillary tumors. Median followup was 33.2 months. There was no difference between tumor groups based on patient age, tumor size or grade, or months of followup. Five-year disease-free survival was 89.7% for clear cell tumors and 100% for papillary tumors (p = 0.041). There was no significant difference in overall survival (88.4% vs 89.6%, p = 0.764)., Conclusions: Radio frequency ablation outcomes seem to be determined in part by renal cell carcinoma subtype with clear cell renal tumors having less favorable outcomes. We hypothesize that this is due to differences in tumor vascularity. Our experience suggests that future tumor ablation studies should consider reporting outcomes based on tumor cell types., (Copyright © 2015 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.)

Background and Purpose: Long-term treatment of patients undergoing definitive management of a small renal mass depends largely on the final pathology determination. Preablation renal biopsy (PABx) is often the only source of determining pathology in patients undergoing thermal ablation of a small renal mass. We sought to evaluate patient and tumor characteristics that may play a role in determining the accuracy of a PABx obtained during radiofrequency ablation (RFA)., Methods: This retrospective study included a review of our prospectively collected database of all laparoscopic and CT-guided RFA (LRFA; CTRFA) performed in our center from November 2001 to July 2013. Three 18-gauge core biopsies were obtained per tumor. Pathology samples were stratified into diagnostic (group 1) and nondiagnostic (ND) (group 2). We used univariate and multivariate analysis to identify potential biopsy result-modifying factors including patient characteristics (age, body mass index [BMI]), biopsy approach (CTRFA vs LRFA), tumor size, orientation, depth, and polarity., Results: A total of 463 treatments in 411 patients were evaluated. Of these, 66% were CTRFA while 34% were LRFA. Mean patient age was 67.4 years (31-88), mean BMI was 28.3 kg/m(2) (16.6-47.2), and mean tumor size was 2.6 cm (0.3-5.5). There was a total of 73 (15.8%) ND biopsies. On multivariate analysis, CTRFA and medial tumors managed with either CTRFA or LRFA were found to be associated with an increased likelihood of a ND biopsy., Conclusion: PABx obtained in patients undergoing CTRFA and from medial tumors managed with either CTRFA or LRFA were more likely to be ND. Future RFA patients should be counseled appropriately. Additional biopsy cores may be needed in these subgroups. Further prospective studies are warranted to confirm these findings.

Background: The distinction between renal cell carcinoma conventional (clear cell) type with eosinophilic morphology (ccRCC), chromophobe renal cell carcinoma eosinophilic variant (chRCC), and renal oncocytoma (RO) is a common diagnostic dilemma. We aimed to identify an immunohistochemical panel to discriminate ccRCC from its morphologic mimics., Materials and Methods: Fifty-three renal neoplasms (19 ccRCC, 18 chRCC, and 16 RO) were selected. Immunohistochemical stains for CD10, cytokeratin 7 (CK7), c-Kit, E-cadherin, N-cadherin, kidney-specific cadherin (Ksp-cadherin), and Recepteur d'origine nantais (RON) were performed., Results: Ten (53%) of 19 ccRCC were positive for CD10, 11 (58%) for E-cadherin, 8 (42%) for N-cadherin, 5 (26%) for Ksp-cadherin, 9 (47%) for RON, 6 (32%) for CK7, and 5 (26%) for c-Kit. In chRCC/RO group, 5 of 34 (15%) were positive for CD10, 32 (94%) for E-cadherin, 2 (6%) for N-cadherin, 1 (3%) for Ksp-cadherin, 22 (65%) for RON, 14 (41%) for CK7, and 25 (25/32, 76%) for c-kit. Univariately, negative c-Kit [odds ratio (OR)=8.75, P=0.001, area under the receiver operating characteristic curve (AUC)=0.747], negative E-cadherin (OR=11.64, P=0.005, AUC=0.681), positive N-cadherin (OR=11.64, P=0.005, AUC=0.681), positive Ksp-cadherin (OR=11.79, P=0.031, AUC=0.617), and positive CD10 (OR=6.44, P=0.005, AUC=0.690) detects ccRCC versus chRCC/RO. Multivariate analysis showed significant association between CD10 positivity and ccRCC (OR=16.90, P=0.007) and between RON negativity and ccRCC (OR=7.17, P=0.047) when CK7 is negative., Conclusions: The best single predictors for ccRCC are negative c-Kit, negative E-cadherin, positive N-cadherin, positive Ksp-cadherin, and positive CD10. However, considering the studied markers, a combination of positive CD10 and negative CK7 and RON is considered the best immunohistochemical panel in distinguishing ccRCC from chRCC/RO.

This manuscript reviews the history of laparoscopic nephrectomy and addresses the future trends of this minimally invasive operation.

Purpose: We investigate the use of 4-phase computerized tomography with intravenous contrast to help distinguish oncocytoma from renal cell carcinoma (RCC) in tumors <4 cm., Methods: We retrospectively identified patients who underwent surgical management for renal tumors <4 cm from 2005 to 2008. Patients who had pre-operative CT evaluation as per our institution's renal mass protocol and had confirmed pathological diagnosis of either oncocytoma or RCC were included in the study. Enhancement readings were obtained for the tumor and the renal cortex using the same slice simultaneously., Results: Our cohort involved 69 patients (46 men, 23 women; mean age 66) who presented with 79 renal masses. Histopathologically 40 were clear cell, 22 papillary, 5 chromophobe RCC and 12 oncocytoma. On the arterial, venous and delayed phase images, oncocytoma showed the highest mean enhancement change, i.e.,546, 396 and 239% followed by clear cell RCC 261, 261 and 174%, chromophobe RCC 147, 127 and 66% and papillary RCC 137, 184 and 118%, respectively. The enhancement pattern differed significantly on comparing oncocytoma with RCC (P < 0.007). The mean percentage contrast excreted at the end of the delayed phase was 33.3, 13.8, 32 and 53% for clear cell, papillary, chromophobe and oncocytoma, respectively., Conclusion: The enhancement and washout values in Hounsfield units obtained by multiphasic CT scan aid in distinguishing oncocytoma from the commonly seen subtypes of RCC in renal masses <4 cm. This preliminary study demonstrates that arterial phase enhancement greater than 500% and washout values of greater than 50% are exclusively seen in renal oncocytomas.

Renal cell carcinoma (RCC) with rhabdoid morphology (RCC-RM) is a recently described variant of RCC, which has an aggressive biologic behavior and poor prognosis, akin to sarcomatoid RCC. The current World Health Organization classification of RCC does not include the rhabdoid phenotype as a distinct histologic entity. The aim of this study is to investigate whether RCC-RM represents a dedifferentiation of a classifiable-type World Health Organization RCC or a carcinosarcoma with muscle differentiation. We reviewed 168 cases of RCC obtained between 2003 and 2008. From these cases, 10 (6%) were found to have areas of classic rhabdoid morphology. Immunohistochemistry for cytokeratin, epithelial membrane antigen, desmin, CD10, and CD117 was performed in each case using the labeled streptavidin-biotin method. Rhabdoid differentiation was identified in association with conventional-type RCC (9) and with unclassifiable-type RCC with spindle cell morphology (1). In all cases, both the rhabdoid and nonrhabdoid tumoral areas were positive for cytokeratin and epithelial membrane antigen and negative for desmin. Cytokeratin positivity in the rhabdoid areas was focal. In cases associated with conventional-type RCC, CD10 was positive in both the rhabdoid and nonrhabdoid foci. CD117 was negative in these tumors. The unclassifiable-type RCC with spindle cell morphology was negative for both CD10 and CD117. The similar immunophenotype between the rhabdoid and nonrhabdoid tumoral foci supports the origin of the rhabdoid cells from the classifiable-type RCC. Areas of rhabdoid morphology do not represent muscle metaplastic differentiation. Renal cell carcinoma with rhabdoid morphology may represent a dedifferentiation of a classifiable-type RCC, similar to that of sarcomatoid differentiation. The recognition of RCC-RM is important as it allows for the inclusion of these high-grade malignancies into a category associated with poor prognosis despite lacking the spindle cell component classically identified as sarcomatoid change., (Copyright © 2011 Elsevier Inc. All rights reserved.)

The advancement of imaging modalities in the past two decades has led to the increased incidence of small renal masses. This same technology is making nephron-sparing treatment of small renal masses much more feasible and precise. The goal of this manuscript is to review the currently available imaging modalities utilized in focal treatment and follow-up of small renal masses.

Objective: To review trends in open partial nephrectomy (OPN) at our center, concentrating on patient selection, technique and perioperative complications., Methods: A comprehensive database was developed by chart review of consecutive patients undergoing OPN for renal masses at our center. Patient selection, technical modifications, perioperative morbidity, and histopathology were compared in patients undergoing OPN between 1992-1999, 2000-2003, and 2004-2008. Complications were divided into procedure-specific (PSCs) and nonspecific medical complications (NMCs). They were graded using the Common Terminology Criteria for Adverse Events (CTCAE), version 3.0., Results: One hundred and sixty-three OPNs were performed. Temporal trends identified include: an increase in the mean patient BMI (p = 0.04), an increase in the percentage of patients with central tumors (p < 0.001), decrease in cold ischemia time (p = 0.045), increasing use of a sequential renal vein clamp (p = 0.03), increasing utilization of tissue sealants (p < 0.001), reduced EBL (p = 0.05), reduced length of stay (p = 0.005), and a decline in PSCs from 16 to 7% (p = 0.002). The incidence of histologically benign tumors declined from 34 to 10% (p = 0.001). Thirty-three (20.2%) patients experienced perioperative complications: 70% were CTCAE grade 1 or 2 adverse events. BMI was the only factor that was found to be associated with the risk of complications on multivariate analysis [odds ratio 1.067, CI 95% (1.002-1.136); p = 0.031]., Conclusions: Increasingly, OPN is being utilized for a cohort of challenging patients who are overweight and have centrally located tumors. Despite this, the risk of PSCs is low. Patients who are overweight are at increased risk for perioperative NMCs.

Introduction: Thermal ablative therapy with cryotherapy and radiofrequency ablation is currently being utilized for treatment of small renal masses. Recently, microwave ablation (MWA) has been investigated for soft tissue destruction, with limited clinical experience for renal masses. This study was designed to evaluate the effectiveness of a new microwave system in the porcine kidney., Materials and Methods: MWAs were performed in vivo on six pigs using the Evident Microwave Ablation System (Valleylab, Boulder, CO) with a 3.7 cm active tip percutaneous antenna. Ablations were performed in both upper and lower poles at 45 W for 3, 5, and 10 minutes. Three pigs died; three pigs survived for 7 days. After necropsy the kidneys were harvested, ablation zones were measured, and histological analysis was performed., Results: The ablated zones at each time interval were inconsistent. The gross appearance of the lesions in both groups was similar. The antenna tract was charred, the collecting system was damaged, and there was asymmetry of the zones of ablation. Histological analysis revealed coagulative necrosis in the area of the ablation with sloughed and denuded urothelium., Conclusion: MWA of the kidney utilizing this model yields inconsistent geometrical lesions when applied near the renal collecting system. Additionally, microwave energy may be preferentially absorbed by the increased water content in the collecting system resulting in damage to it. Further study is needed to assess the attenuation of the microwave field in the kidney at different locations due to the kidneys heterogeneity.

Current clinical requirements mandate the existence of a renal diuretic protocol, which is fast and easy, applicable in all ages and for all indications, convenient for both the patient and the technologist, and provides diagnostic as well as prognostic information. Seventeen years ago a 25-minute protocol, after oral hydration, with no bladder catheterization, and simultaneous injection of mercapto-acetyl-triglycine (MAG(3)) and furosemide (MAG(3)-F(0)), was initiated. It initially was used for the evaluation of drainage and emerged as a protocol to also evaluate the renal parenchyma. Results of this protocol have been published individually, per clinical application. MAG(3)-F(0) was instrumental in the evaluation and prognosis of congenital disorders. For obstruction, in the newborn, an increasing renogram mandates intervention, whereas a downsloping one predicts spontaneous resolution. In children or adults, preoperatively or postoperatively, when the cortex was visualized and drained normally, there was no obstruction, even if urine was retained within a dilated collecting system or an extrarenal pelvis. For diseases of the renal parenchyma, the protocol enabled the diagnosis of acute pyelonephritis (APN) revealing the "regional parenchymal dysfunction," diagnostic of APN. Diffuse parenchymal diseases were characterized by increased residual cortical activity (RCA), and their progression was manifested as a deterioration of RCA. End-stage renal disease was characterized by lack of accumulation and retention. Trauma and leaks were identified with specific patterns. In renovascular hypertension (RVH), an increase in RCA after angiotension-converting enzyme inhibitors is diagnostic of RVH and prognostic of the beneficial effect of angioplasty on hypertension. In renal colic, stratification was possible into (1) complete or severe obstruction requiring immediate intervention, (2) mild obstruction allowing waiting, (3) spontaneous decompression (stunned kidney), and (4) no recent obstruction. In transplants, it enabled differentiation of acute tubular necrosis, acute or chronic rejection and nephrotoxicity, and identified infarcts, RVH, leaks and obstruction. Finally, this method allows for a quick semiquantification of renal function. The clinical usefulness of the MAG(3)-F(0) protocol in most congenital or acquired renal problems is proven through long-term clinical experience and has resulted in a substantial utilization of the test at our Center.

Purpose: The optimal management of lower pole renal calculi is controversial. We compared shock wave lithotripsy (SWL) and ureteroscopy (URS) for the treatment of patients with small lower pole stones in a prospective, randomized, multicenter trial., Materials and Methods: A total of 78 patients with 1 cm or less isolated lower pole stones were randomized to SWL or URS. The primary outcome measure was stone-free rate on noncontrast computerized tomography at 3 months. Secondary outcome parameters were length of stay, complication rates, need for secondary procedures and patient derived quality of life measures., Results: A total of 67 patients randomized to SWL (32) or URS (35) completed treatment. The 2 groups were comparable with respect to age, sex, body mass index, side treated and stone surface area. Operative time was significantly shorter for SWL than URS (66 vs 90 minutes). At 3 months of followup 26 and 32 patients who underwent SWL and URS had radiographic followup that demonstrated a stone-free rate of 35% and 50%, respectively (p not significant). Intraoperative complications occurred in 1 SWL case (unable to target stone) and in 7 URS cases (failed access in 5 and perforation in 2), while postoperative complications occurred in 7 SWL and 7 URS cases. Patient derived quality of life measures favored SWL., Conclusions: This study failed to demonstrate a statistically significant difference in stone-free rates between SWL and URS for the treatment of small lower pole renal calculi. However, SWL was associated with greater patient acceptance and shorter convalescence.

Background: Radiofrequency (RF) ablation is used to obtain local control of unresectable tumors in liver, kidney, prostate, and other organs. Accurate data on expected size and geometry of coagulation zones are essential for physicians to prevent collateral damage and local tumor recurrence. The aim of this study was to develop a standardized terminology to describe the size and geometry of these zones for experimental and clinical RF., Methods: In a first step, the essential geometric parameters to accurately describe the coagulation zones and the spatial relationship between the coagulation zones and the electrodes were defined. In a second step, standard terms were assigned to each parameter., Results: The proposed terms for single-electrode RF ablation include axial diameter, front margin, coagulation center, maximal and minimal radius, maximal and minimal transverse diameter, ellipticity index, and regularity index. In addition a subjective description of the general shape and regularity is recommended., Conclusions: Adoption of the proposed standardized description method may help to fill in the many gaps in our current knowledge of the size and geometry of RF coagulation zones.

Background and Purpose: A number of clinical variables are believed to be risk factors for complications of laparoscopic renal surgery. We reviewed our experience with laparoscopic surgery specifically for renal cancers to better clarify which clinical variables were significant risk factors., Methods: Our laparoscopic experience with 210 cases of renal cancer from April 1999 through August 2004 was reviewed. Preoperative clinical characteristics were recorded. Complete information was available for 134 patients: 54 radical nephrectomies, 41 nephroureterectomies, 19 radiofrequency ablations, and 20 partial nephrectomies. Outcomes monitored included blood loss, length of hospital stay, conversion, blood transfusion, and intraoperative, minor postoperative, and major postoperative complications. Multivariate analysis was performed to determine whether any variable was a significant risk factor for adverse outcomes during or after laparoscopic surgery., Results: The numbers of patients requiring operative conversion or blood transfusions were 6 (4.5%) and 20 (14.9%), respectively. Intraoperative, minor postoperative, and major postoperative complication occurred in 9 (6.7%), 22 (16.4%), and 11 (8.2%) patients, respectively. The year surgery was performed was inversely proportional to the incidence of minor postoperative complications, implying a protective association with the experience of the surgeon. On multivariate analysis, only body mass index (BMI) was found to be a significant risk factor for major postoperative complications with an odds ratio of 1.14 (P = 0.03)., Conclusions: Laparoscopic surgery is safe, but with every unit increase in the BMI, the risk of a major complication increases by 14%.

Objective: Research on technology for soft tissue radio frequency (RF) ablation is ever advancing. A recent proposal to standardize terminology of RF electrodes only deals with the most frequently used commercial electrodes. The aim of this study was to develop a logical, versatile, and unequivocal terminology to describe present and future RF electrodes and multiple electrode systems., Materials and Methods: We have carried out a PubMed search for the period from January 1st 1990 to July 1st 2004 in seven languages and contacted the six major companies that produce commercial RF electrodes for use in the liver. In a first step, names have been defined for the five existing basic designs of single-shaft electrode. These names had to be unequivocal, descriptive of the electrode's main working principle and as short as possible. In a second step, these basic names have been used as building blocks to describe the single-shaft electrodes in combination designs. In a third step, using the same principles, a logical terminology has been developed for multiple electrode systems, defined as the combined use of more than one single-shaft RF electrode., Results: Five basic electrode designs were identified and defined: plain, cooled, expandable, wet, and bipolar electrodes. Combination designs included cooled-wet, expandable-wet, bipolar-wet, bipolar-cooled, bipolar-expandable, and bipolar-cooled-wet electrodes. Multiple electrode systems could be characterized by describing several features: the number of electrodes that were used (dual, triple, etc.), the electric mode (monopolar or bipolar), the activation mode (consecutive, simultaneous or switching), the site of the inserted electrodes (monofocal or multifocal), and the type of single-shaft electrodes that were used., Conclusion: In this terminology, the naming ofthe basic electrode designs has been based on objective criteria. The short and unequivocal names of the basic designs can easily be combined to describe current and future combination electrodes. This terminology provides an exact and complete description of the versatile novel multiple electrode systems.

Purpose: The optimal management of lower pole renal calculi is controversial. We compared shock wave lithotripsy (SWL) and ureteroscopy (URS) for the treatment of patients with small lower pole stones in a prospective, randomized, multicenter trial., Materials and Methods: A total of 78 patients with 1 cm or less isolated lower pole stones were randomized to SWL or URS. The primary outcome measure was stone-free rate on noncontrast computerized tomography at 3 months. Secondary outcome parameters were length of stay, complication rates, need for secondary procedures and patient derived quality of life measures., Results: A total of 67 patients randomized to SWL (32) or URS (35) completed treatment. The 2 groups were comparable with respect to age, sex, body mass index, side treated and stone surface area. Operative time was significantly shorter for SWL than URS (66 vs 90 minutes). At 3 months of followup 26 and 32 patients who underwent SWL and URS had radiographic followup that demonstrated a stone-free rate of 35% and 50%, respectively (p not significant). Intraoperative complications occurred in 1 SWL case (unable to target stone) and in 7 URS cases (failed access in 5 and perforation in 2), while postoperative complications occurred in 7 SWL and 7 URS cases. Patient derived quality of life measures favored SWL., Conclusions: This study failed to demonstrate a statistically significant difference in stone-free rates between SWL and URS for the treatment of small lower pole renal calculi. However, SWL was associated with greater patient acceptance and shorter convalescence.

Research on technology for soft tissue radiofrequency (RF) ablation is ever advancing. A recent proposal to standardise terminology of RF electrodes only deals with the most frequently used commercial electrodes. The aim of this study was to develop a logical, versatile and unequivocal terminology to describe present and future RF electrodes and multiple electrode systems. We have carried out a PubMed search for the period from January 1 1990 to July 1 2004 in seven languages and contacted the six major companies that produce commercial RF electrodes for use in clinic. In a first step, names have been defined for the five existing basic designs of single-shaft electrode. These names had to be unequivocal, descriptive of the electrode's main working principle and as short as possible. In a second step, these basic names have been used as building blocks to describe the single-shaft electrodes in combination designs. In a third step, using the same principles, a logical terminology has been developed for multiple electrode systems, defined as the combined use of more than one single-shaft RF electrode. Five basic electrode designs were identified and defined: plain, cooled, expandable, wet and bipolar electrodes. Combination designs included cooled-wet, expandable-wet, bipolar-wet, bipolar-cooled, bipolar-expandable and bipolar-cooled-wet electrodes. Multiple electrode systems could be characterised by describing several features: the number of electrodes that were used (dual, triple, ...), the electric mode (monopolar or bipolar), the activation mode (consecutive, simultaneous or switching), the site of the inserted electrodes (monofocal or multifocal), and the type of single shaft electrodes that were used. In this terminology, the naming of the basic electrode designs has been based on objective criteria. The short and unequivocal names of the basic designs can easily be combined to describe current and future combination electrodes. This terminology provides an exact and complete description of the versatile novel multiple electrode systems.

Purpose: The efficacy of shock wave lithotripsy and percutaneous stone removal for the treatment of symptomatic lower pole renal calculi was determined., Materials and Methods: A prospective randomized, multicenter clinical trial was performed comparing shock wave lithotripsy and percutaneous stone removal for symptomatic lower pole only renal calculi 30 mm. or less., Results: Of 128 patients enrolled in the study 60 with a mean stone size of 14.43 mm. were randomized to percutaneous stone removal (58 treated, 2 awaiting treatment) and 68 with a mean stone size of 14.03 mm. were randomized to shock wave lithotripsy (64 treated, 4 awaiting treatment). Followup at 3 months was available for 88% of treated patients. The 3-month postoperative stone-free rates overall were 95% for percutaneous removal versus 37% lithotripsy (p <0.001). Shock wave lithotripsy results varied inversely with stone burden while percutaneous stone-free rates were independent of stone burden. Stone clearance from the lower pole following shock wave lithotripsy was particularly problematic for calculi greater than 10 mm. in diameter with only 7 of 33 (21%) patients becoming stone-free. Re-treatment was necessary in 10 (16%) lithotripsy and 5 (9%) percutaneous cases. There were 9 treatment failures in the lithotripsy group and none in the percutaneous group. Ancillary treatment was necessary in 13% of lithotripsy and 2% percutaneous cases. Morbidity was low overall and did not differ significantly between the groups (percutaneous stone removal 22%, shock wave lithotripsy 11%, p =0.087). In the shock wave lithotripsy group there was no difference in lower pole anatomical measurements between kidneys in which complete stone clearance did or did not occur., Conclusions: Stone clearance from the lower pole following shock wave lithotripsy is poor, especially for stones greater than 10 mm. in diameter. Calculi greater than 10 mm. in diameter are better managed initially with percutaneous removal due to its high degree of efficacy and acceptably low morbidity.

Unlabelled: Patients with renal colic are evaluated with clinical, laboratory, and imaging methods for stratification for emergency decompression, medical treatment, or discharge and follow up. The current standard practice is heavily based on unenhanced helical CT for detecting uroliths. However, the presence of a urolith does not necessarily mean that the kidney is obstructed and requires emergency decompression. In this study, technetium-mercaptoacetyltriglycine (MAG3) diuretic scintirenography was used to detect obstruction in patients with renal colic. The contribution of this test to patient management after positive findings from helical CT was also studied., Methods: Diagnostic criteria were established on the basis of previous experience with 60 patients who had renal colic and had undergone radiography of the kidneys, ureters, and urinary bladder (KUB) and diuretic Tc-MAG3 scintirenography and were followed up to correlate scintigraphic findings with clinical outcome. Subsequently, 80 patients with renal colic underwent scintigraphy within 12 h of presentation in the emergency room, after abdominal helical CT showed findings positive for calculus and suggestive of obstruction. After therapeutic oral or intravenous hydration and analgesics, diuretic dynamic renal scintigraphy (flow, function, delayed imaging) was performed after intravenous injections of 10 mCi (370 MBq) 99mTc-MAG3 and 40 mg furosemide (at zero time, or F0). Results were available soon after completion of the study and were considered in patient management. Four characteristic patterns of scintirenography, essential in patient stratification and treatment, had been standardized and were used for interpretation of the studies: the unobstructed kidney; the partially obstructed kidney, proximally or distally obstructed, with mild to severe obstruction and impairment of function; the totally obstructed kidney, with arrested renal function; and the unobstructed but dysfunctioning kidney after decompression, or stunned kidney., Results: Among the 80 patients with positive helical CT findings, 56.5% were found to have obstruction by scintigraphy (32.5% partially, 24% completely); the remaining 43.5% did not have obstruction (21% without an indication of recent obstruction and 22.5% with stunned kidneys after spontaneous decompression). Occasionally, findings of preexistent urine extravasation or infection were present. Patients who, by scintigraphy, never had obstruction or had experienced spontaneous decompression did not require admission or emergency intervention; those with complete or severe obstruction required admission and decompression for relief of pain or restoration of function, whereas those with mild obstruction were treated variably with forced fluids, analgesics, or, less frequently, elective surgery. Outcome information from clinical examination, imaging, and interventional findings indicated that this stratification was successful. The test caused no side effects., Conclusion: For renal colic, clinical selection, KUB radiography, and even positive helical CT findings were all found to have a low positive predictive value for obstruction (in this study, 35%, 32%, and 56% respectively). Anatomic studies, including helical CT, should be followed by diuretic MAG3-F0 scintirenography to diagnose and quantify or exclude obstruction, detect spontaneous decompression, and appropriately stratify patients for emergency intervention, observation and medical therapy, or further work-up and discharge with referral to the clinic.

Background and Purpose: The percentage of small renal tumors being diagnosed has increased at least five-fold in the last 20 years. The question of how best to treat these lesions remains unanswered. We studied the effectiveness of "wet" radiofrequency (RF) ablation of renal tissue., Materials and Methods: New Zealand white rabbits (N = 48) underwent a 1- or 2-minute ablation of renal parenchyma with a modified insulated spinal needle capable of infusing saline, measuring temperature and impedance, and delivering RF energy. Animals were followed and examined up to 54 days after surgery., Results: All animals survived for the planned period. Intravenous urograms showed no fistula or urinoma formation and confirmed continued function of the remaining parenchyma. The 1-minute treatments consistently ablated 20% to 25% (average 7 cm) of the tissue, whereas the 2-minute treatments ablated 34% to 36% (average 10 cm). Acutely, there was coagulative necrosis and infiltration of inflammatory cells. Chronically, there were well-demarcated lesions with complete effacement of the tubular epithelium and destruction of the glomeruli., Conclusion: Wet radiofrequency ablation with a liquid electrode can reproducibly create large lesions safely and quickly. The technique may soon become an alternative, minimally invasive therapy for small renal tumors.

Recurrent or intractable ureteral strictures pose a significant problem for the practicing urologist. Metallic stents have been used sparingly for this problem with varying success. We investigated the use of a stent-graft consisting of a metal stent lined with a porous biocompatible polymer to determine if the liner would prevent urothelial ingrowth. One ureter of each of 11 dogs was treated with either a metallic woven stent or stent-graft inserted retrograde via a midline cystotomy. Six bare wire stents (controls) and five lined with a new, porous, biocompatible, polycarbonate elastomer liner (Corethane) were placed. The animals were followed radiographically with intravenous urography (IVP) at 6 weeks and just prior to sacrifice (12 to 22 weeks). Gross, histological, and electron microscopic analyses were performed. The results demonstrate that all of the bare metal stented animals developed moderate to severe hydroureteronephrosis with significant urothelial hyperplasia and ingrowth through the spaces between the metal wires. The animals implanted with lined stents showed one instance of mild hydroureteronephrosis (observed radiographically but not grossly at time of sacrifice) and virtually no papillary in-growths of urothelium through the stent interstices. This obstructive phenomenon was prevented by the porous polymer lining. There was no evidence of biodegradation of the liner on scanning electron microscopy. Based upon these findings, the marriage of a biocompatible polymer which provokes minimal tissue reaction, and metallic stents which provide tremendous strength, seems to offer significant advantages when placed into the urinary tract to maintain ureteral luminal patency.

We hoped to determine the number of pulses and energy needed to create acute ureteral perforations with four different lithotripters in a reproducible ex vivo model. A simple model was constructed to control variables in the testing such as wall thickness, intraluminal pressure, distance between the probe tip and ureter, and power delivered to tissue. Segments of domestic pig ureter were prepared and fixed in position in a normal saline (NS) bath at room temperature. We then attempted perforation with the holmium:YAG (HoL) laser, coumarin pulsed-dye laser (CdL), electrohydraulic lithotripter (EHL), and pneumatic impactor (PI) by placing the instrument probes at right angles to the ureteral wall. The ureter was filled with a methylene blue-stained solution of NS at 90 cm H2O pressure via a urodynamics catheter, and perforation was recorded on initial extravasation of dye. The endpoints measured were time to perforation and total energy required. At 0.5 mm of separation between the wall and probe, the HoL perforated the ureter in an average of 2 seconds and 0.01 kJ delivered at 5 W (10 Hz and 0.5 J/pulse). The EHL perforated at an average of 24.44 +/- 8.77 seconds and a total energy of 0.01 +/- 0 kJ. The CdL was able to perforate but at much longer intervals (257.51 +/- 99.08 seconds) and higher energy levels (12.88 +/- 4.95 kJ) on average than either the EHL or HoL. Lastly, the PI was unable to perforate the ureter in more than 6 continuous minutes of application. In addition, we found that at 2-mm separation between the HoL probe tip and the ureteral wall, acute perforation was not possible even at very high power settings. We conclude that although each endoscopic lithotripter has advantages as well as disadvantages, in this ex vivo model, it was clear that the HoL and EHL can easily perforate the ureter and must be used with vigilance. It was found that at 2 mm of separation between the probe and target, the HoL, was unable to perforate acutely. The CdL and PI were associated with a much higher safety index, and the PI was unable to produce ureteral perforation.

A novel technique for prostate ablation using radiofrequency (RF) energy coupled to tissue with interstitial perfusion of saline solutions from a screw-tip catheter has been developed. The electrolyte spreads the current density away from the metal electrode and increases the effective electrode surface area, allowing more RF power input. This prevents tissue desiccation and impedance rise, resulting in controlled production of large lesions. In this study, we attempted to produce similar results using a straight needle and the saline electrode with a transurethral approach and compared the results with those of the same technique without electrolyte perfusion (conventional RF method). For this study, we designed an insulated 22-gauge needle with thermocouples embedded along its length and a 1-cm exposed tip with a retractable intraluminal thermocouple. This needle was inserted into the urethra of 10 dogs through a small perineal incision. Under transrectal ultrasound guidance, the exposed tip of the needle was placed in the center of each lobe. The intraluminal thermocouple was moved from the exposed tip up to the prostate capsule to monitor temperature. The highest power that could be applied in conventional RF methods without immediate desiccation was determined from preliminary experiments as 10 W. Subsequently, 10 W of RF power (475 kHZ) was delivered in one lobe until either the capsule temperature reached 48 degrees C or high impedance (> 400 omega) occurred. In the other lobe, 50 W of RF energy (475 kHz) and electrolyte perfusion (14.6% NaCl, 1 mL/min) were delivered until the capsule temperature reached 48 degrees C or high impedance occurred. Prostate lobe sizes ranged from 3.93 cm3 to 44.47 cm3 (mean 15.07 cm3). At 10 W without saline perfusion, high impedance from tissue desiccation occurred at 45 +/- 27 seconds, with lesions ranging from 0.06 cm3 to 0.93 cm3 (mean 0.34 cm3). At 50 W with saline perfusion, there was no tissue desiccation or impedance rise. The RF application time averaged 181 +/- 115 seconds until the capsule reached 48 degrees C, resulting in lesions ranging from 2.53 cm3 to 22.88 cm3 (mean 8.54 cm3). This study demonstrates that transurethral ablation of the prostate with a saline electrode allows controlled production of larger lesions than conventional RF methods. This may permit a single RF application in each lobe to produce lesions effective for the treatment of benign prostatic hyperplasia even in large glands.

We compared general anesthesia and intravenous sedation-analgesia for SWL on a Dornier HM3 lithotripter with respect to treatment and anesthesia time, X-ray exposure, shockwaves administered, and efficacy. The case records of 49 patients receiving general anesthesia and 118 patients who underwent intravenous sedation-analgesia were examined. Follow-up plain abdominal radiographs were evaluated for residual stones. Treatments accomplished under intravenous sedation-analgesia required less anesthesia time and less SWL time. The amount of fluoroscopy time was increased. The success rate in treating patients with these two types of anesthesia was not significantly different. Intravenous sedation-analgesia is safe and effective for shockwave lithotripsy in the HM3 lithotripter. This technique facilitates more rapid outpatient treatment and has excellent patient tolerance.

Objectives: Significant obesity is considered to be a relative contraindication to laparoscopic surgery. This study reviews the complications encountered in massively obese patients undergoing urologic laparoscopic surgery., Methods: Body mass index (BMI) was used as an objective index to indicate massive obesity. Eleven institutions compiled retrospective data on 125 patients having a BMI greater than 30. Procedures performed included 76 pelvic lymph node dissections, 14 nephrectomies, 7 bladder neck suspensions, and 28 miscellaneous procedures., Results: For the group as a whole, the mean BMI was 35.1 (range 30.1 to 57.2). Mean operative time was 202 minutes (range 60 to 480). Conversion to open surgery occurred in 15 of the 125 patients (12%). Complication rates (minor and major) were 22% (27 occurrences in 125 patients) intraoperatively and 26% (33 occurrences in 125 patients) postoperatively. The major complications included 2 trocar injuries to abdominal wall vessels, 1 bladder injury, 3 peripheral nerve injuries, 1 dysrhythmia, 1 deep vein thrombosis, 1 wound seroma, 1 nephrocutaneous fistula, 1 incisional hernia, and 1 death., Conclusions: In this review, complication rates for urologic laparoscopic surgery on massively obese patients were higher than in the general population undergoing laparoscopic surgery (0.3% to 21%).

Conventional radiofrequency (RF) ablative techniques have shown promise for the treatment of symptomatic benign prostatic hyperplasia (BPH); however, present RF technology is limited by the small lesion size, necessitating several probe placements and heating cycles to achieve sizable lesions. This limitation is attributable primarily to a rapid increase in electrical impedance secondary to tissue desiccation and charring at the electrode tip. We devised a hollow screw-tip needle electrode that permits fixation to tissue, recording of temperature and impedance, infusion of fluid, and delivery of RF energy. Infusion of electrolyte solution (i.e., saline) into tissue prevents impedance rise by conducting RF energy away from the metal electrode and permits the creation of large lesions. By varying the conductivity of the perfusate (concentration and temperature), lesions of large diameter can be created in a controlled manner. To determine the long-term tissue effects, we applied this new modified RF technique to the prostates of five mongrel dogs in a chronic (0.5 to 8-week) study. The screw-tip electrode was serially embedded into each lobe of the perineally exposed glands with 1-minute infusion of 0.9% saline (2 mL/min) followed by application of RF energy (500 KHz, 50 W, 2-18 minutes) along with continuous saline infusion. Thermocouples were embedded 5 mm below and at the gland capsule, and RF application was discontinued when the temperature reached 50 degrees C at the periphery. Postoperatively, the animals were examined daily for clinical status and weekly for glandular changes using transrectal ultrasonography. At predetermined intervals, the animals were sacrificed and the prostates excised, measured, sectioned, and examined for histologic changes. Ablative tissue temperatures of 50 to 100 degrees C were produced while impedance remained stable. Four animals required a single catheterization for relief of urinary retention between days 2 and 3; otherwise, all animals demonstrated a quick and uneventful recovery with no edema detectable on day 7 ultrasound examination. The outside dimensions of the gland remained relatively constant throughout the study (+ or - 0.39 cm L + W + H). Histologic examination revealed coagulation necrosis (ablation) in both lobes of all prostates (69.94% + or - 16.62% of the gland) with tissueless cavities forming from the ablation area (28.71% + or - 8.24% of the gland) contained within the capsule surrounded by healthy tissue at the periphery. Intraprostatic lesions were obtained without any gross damage to surrounding tissue, including the bladder and rectal wall. Utilizing a liquid conductor in prostate tissue allows a single electrode-placement heating cycle for controlled ablation for the potential treatment of BPH. This new technique produces more extensive and uniform lesions than conventional RF procedures, and lesion size is limited only by the duration of RF energy application.

Although they are rarely associated with complaints, benign renal cysts may be the cause of pain, hypertension, or other problems. Simple aspiration is rarely definitive treatment. We have had good results with three laparoscopic approaches to cyst unroofing: transperitoneal, with reflection of the colon medially or dissection through the mesocolon and direct retroperitoneoscopy. We recommend initial percutaneous aspiration with cytology study both to rule out malignancy and to identify those cysts clearly in need of unroofing.

We report a case of an elective laparoscopic transperitoneal removal of a large renal cyst by dividing the colonic mesentery without mobilizing the colon to gain access to the kidney. This appears to be a safe and potentially less costly approach compared to the standard flank approach of these simple renal cysts.

Treatment of distal ureteral stones with the Dornier HM3 lithotriptor depends on the localization and positioning of the calculus from a transgluteal approach. We found the Stryker frame gantry modification preferable to the standard gantry for treatment of stones in the distal ureter. We report the use of this gantry adaptation in 22 cases of distal ureteral stones. The calculi were localized in 100% of the cases and were fragmented successfully with 1 treatment in 89%. In no case was the procedure aborted secondary to nonvisualization of the calculus. Failure to disintegrate the stone requiring retreatment occurred in 11% of the cases, and was attributed to stone characteristics and not due to difficulty with visualization or placement of the calculus within the F2 focus. The average fluoroscopic time was 45 seconds. The Stryker frame modification to the standard Dornier HM3 lithotriptor allows for improved visualization and easier localization of distal ureteral calculi compared to the standard gantry.

Operative common bile duct exploration, performed in conjunction with cholecystectomy, has been considered the treatment of choice for choledocholithiasis in the presence of an intact gallbladder. With the advent of laparoscopic cholecystectomy, the management of common bile duct stones has been affected. More emphasis is being placed on endoscopic sphincterotomy and options other than operative common duct exploration. Because of this increasing demand, we have developed a new technique for laparoscopic common bile duct exploration performed in the same operative setting as laparoscopic cholecystectomy. A series of five patients who successfully underwent common bile duct exploration, flexible choledochoscopy with stone extraction, and T-tube drainage, all using laparoscopic technique, is reported. Mean postoperative length of hospital stay was 4.6 days. Outpatient T-tube cholangiography was performed in all cases and revealed normal ductal anatomy with no retained stones. Follow-up ranged from 6 weeks to 4 months, and all patients were asymptomatic and had normal liver function tests.