Minimally invasive percutaneous management of large bladder stones with a laparoscopic entrapment bag.

INTRODUCTION: The treatment of large volume bladder stones is a management conundrum. Transurethral methods are plagued by long operative times, trauma to the bladder mucosa, and the need for a postoperative urethral catheter. Open cystolithotomy has higher morbidity. We present the percutaneous management of bladder stones with the novel use of a laparoscopic entrapment bag. MATERIALS AND METHODS: Twenty-five patients (mean age 65.7), including 22 men and 3 women, 4 with a neurogenic bladder and 21 with a prior diagnosis of benign prostatic hyperplasia, underwent our novel technique. The mean number of stones was 6.8±8.0 (range, 1 to 30) and total stone burden 10.4±10.5 cm (range, 3.0 to 50.0 cm). Using regional or general anesthesia and flexible cystoscopic guidance, percutaneous bladder access was achieved. The tract was balloon dilated to 30F and stones captured in a laparoscopic entrapment bag. The bag's opening was exteriorized and stone fragmentation and comminution were achieved using a nephroscope and pneumatic or ultrasonic lithotripters. The bag was extracted and a 22F suprapubic catheter was inserted into the bladder; the patient was discharged the next day after a voiding trial. The procedure was done without fluoroscopy. No foley catheter was necessary. RESULTS: All patients were rendered stone free. The mean estimated blood loss was 11.1±3.93 mL (range, 10 to 25 mL). The mean operative time was 102.3 minutes. There was minimal trauma to the bladder mucosa and no complications of fluid extravasation, hematuria, or urethral trauma were noted. All patients were discharged within 24 hours of the operation. CONCLUSION: Percutaneous cystolithotomy with the use of an entrapment bag is an efficient, safe technique for treating large volume bladder calculi. We recommend this technique as an alternative to open surgery for patients with too large a stone burden to remove transurethrally.

A comparison of long term renal functional outcomes following partial nephrectomy and radiofrequency ablation.

INTRODUCTION: To compare long term glomerular filtration rate (GFR) outcomes of partial nephrectomy and radiofrequency ablation performed for renal malignancy. MATERIALS AND METHODS: Renal function of 347 patients undergoing radiofrequency ablation (n = 142) or partial nephrectomy (n = 205) for renal malignancy between 1994 and 2011 were compared from a retrospective database at a single tertiary care center. Minimum 1 year of follow up was required, resulting in a mean follow up of 48.2 (SD +/- 28.2) months. Renal function was estimated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation. The primary study outcome was progression of Chronic Kidney Disease (CKD) stage, calculated using the Kaplan-Meier life table method. Multivariate analysis was also conducted to determine the level of association between GFR decline and treatment modality. RESULTS: The 5 year freedom from CKD stage progression for radiofrequency ablation and partial nephrectomy was 85.4% (95% CI 76.8%-91.1%) versus 82.1% (95% CI 73.7%-88.1%) (p = 0.06). A longer follow up interval was associated with greater GFR decline, although hypertension, diabetes, age, and tumor size were not. CONCLUSION: Radiofrequency ablation provides similar long term renal function preservation benefit as partial nephrectomy.

Minimally invasive pyeloplasty in horseshoe kidneys with ureteropelvic junction obstruction: a case series.

BACKGROUND AND PURPOSE: Horseshoe kidney is an uncommon renal anomaly often associated with ureteropelvic junction (UPJ) obstruction. Advanced minimally invasive surgical (MIS) reconstructive techniques including laparoscopic and robotic surgery are now being utilized in this population. However, fewer than 30 cases of MIS UPJ reconstruction in horseshoe kidneys have been reported. We herein report our experience with these techniques in the largest series to date. MATERIALS AND METHODS: We performed a retrospective chart review of nine patients with UPJ obstruction in horseshoe kidneys who underwent MIS repair at our institution between March 2000 and January 2012. Four underwent laparoscopic, two robotic, and one laparoendoscopic single-site (LESS) dismembered pyeloplasty. An additional two pediatric patients underwent robotic Hellstrom repair. Perioperative outcomes and treatment success were evaluated. RESULTS: Median patient age was 18 years (range 2.5-62 years). Median operative time was 136 minutes (range 109-230 min.) and there were no perioperative complications. After a median follow-up of 11 months, clinical (symptomatic) success was 100%, while radiographic success based on MAG-3 renogram was 78%. The two failures were defined by prolonged t1/2 drainage, but neither patient has required salvage therapy as they remain asymptomatic with stable differential renal function. CONCLUSIONS: MIS repair of UPJ obstruction in horseshoe kidneys is feasible and safe. Although excellent short-term clinical success is achieved, radiographic success may be lower than MIS pyeloplasty in heterotopic kidneys, possibly due to inherent differences in anatomy. Larger studies are needed to evaluate MIS pyeloplasty in this population.

Minimally Invasive Pyeloplasty in Horseshoe Kidneys with Ureteropelvic Junction obstruction: A case series

Background and Purpose Horseshoe kidney is an uncommon renal anomaly often associated with ureteropelvic junction (UPJ) obstruction. Advanced minimally invasive surgical (MIS) reconstructive techniques including laparoscopic and robotic surgery are now being utilized in this population. However, fewer than 30 cases of MIS UPJ reconstruction in horseshoe kidneys have been reported. We herein report our experience with these techniques in the largest series to date. Materials and Methods We performed a retrospective chart review of nine patients with UPJ obstruction in horseshoe kidneys who underwent MIS repair at our institution between March 2000 and January 2012. Four underwent laparoscopic, two robotic, and one laparoendoscopic single-site (LESS) dismembered pyeloplasty. An additional two pediatric patients underwent robotic Hellstrom repair. Perioperative outcomes and treatment success were evaluated. Results Median patient age was 18 years (range 2.5-62 years). Median operative time was 136 minutes (range 109-230 min.) and there were no perioperative complications. After a median follow-up of 11 months, clinical (symptomatic) success was 100%, while radiographic success based on MAG-3 renogram was 78%. The two failures were defined by prolonged t1/2 drainage, but neither patient has required salvage therapy as they remain asymptomatic with stable differential renal function. Conclusions MIS repair of UPJ obstruction in horseshoe kidneys is feasible and safe. Although excellent short-term clinical success is achieved, radiographic success may be lower than MIS pyeloplasty in heterotopic kidneys, possibly due to inherent differences in anatomy. Larger studies are needed to evaluate MIS pyeloplasty in this population. .

Irreversible electroporation: evaluation of nonthermal and thermal ablative capabilities in the porcine kidney.

OBJECTIVE: To compare the renal ablative capabilities of nonthermal irreversible electroporation (NT-IRE) with those of thermal irreversible electroporation (T-IRE) in a porcine model. MATERIALS AND METHODS: A total of 24 laparoscopic renal ablations were performed in 12 pigs using a novel generator capable of alternately delivering NT-IRE and T-IRE. Each pig underwent unilateral interpolar ablation straddling the renal pelvis and lower pole ablation, using a single modality. The pigs were killed at 24 hours and 7 and 21 days. Basic serum laboratory tests, cardiac enzyme levels, and retrograde pyelograms were obtained before and immediately after ablation and at death. Ablation adequacy and lesion size were assessed by histologic examination. RESULTS: All procedures were successfully completed without complications. For NT-IRE vs T-IRE, the median lesion size (long axis) at 24 hours, 7 days and 21 days was 3.0 vs 3.3 cm (P = 1.0), 2.5 vs 3.9 cm (P = .04), and 1.2 vs 2.8 cm (P = .03), respectively. Prolonged urinary extravasation and collecting system scarring were observed only for T-IRE. Both NT-IRE and T-IRE ablated the renal tissue adequately. NT-IRE was characterized by acute hemorrhagic necrosis, sparing the large blood vessels and extracellular matrix, and T-IRE by coagulation necrosis with associated moderate inflammation. CONCLUSION: NT-IRE and T-IRE both safe and effectively ablate normal porcine kidneys. NT-IRE created smaller lesions with unique histologic characteristics. Significant collecting system injury occurred with T-IRE. Additional preclinical evaluation aimed at optimizing the ablation protocols is needed.

Renal oxygenation during robot-assisted laparoscopic partial nephrectomy: characterization using laparoscopic digital light processing hyperspectral imaging.

UNLABELLED: Abstract Background and Purpose: Digital light processing-based hyperspectral imaging (DLP(®)-HSI) was adapted for use during laparoscopic surgery by coupling the spectral illumination source with a conventional laparoscopic light guide and incorporating a customized digital charge-coupled device camera for image acquisition. The system was used to characterize renal oxygenation during robot-assisted laparoscopic partial nephrectomy (RALPN) in humans. PATIENTS AND METHODS: After Institutional Review Board approval, laparoscopic DLP-HSI was performed in consecutive patients undergoing RALPN at our institution. Time trends in relative tissue oxygen saturation (%HbO2) were descriptively analyzed. Associations between %HbO2 and patient age, comorbidities, and estimated glomerular filtration rate (eGFR) were investigated using the Kendall tau test. RESULTS: Laparoscopic DLP-HSI was performed in 18 patients between May 2011 and February 2012. Median (interquartile range; IQR) age was 55.9 (49-67.5) years. Of the patients, 10/18 (56%) were men and 12/18 (66.7%) had a history of hypertension, diabetes, and/or tobacco use. Median (IQR) %HbO2 before, during, and after ischemia was 60.8% (57.9-68.2%), 53.6% (46.8-55.1%), and 61.5% (54.9-67.6%), respectively. Baseline %HbO2 was inversely associated with preoperative eGFR (τ=-0.38; P=0.036), and eGFR at most recent follow-up (τ=-0.38; P=0.036). Baseline or ischemic %HbO2 did not correlate with hypertension, diabetes, and/or tobacco history. Younger patients (<56 years) had a lower median baseline %HbO2 (P=0.07) and a higher median preoperative eGFR (P=0.038), than their older counterparts. CONCLUSION: The laparoscopic HSI system successfully characterized dynamic changes in renal oxygenation during RALPN. Intraoperative laparoscopic HSI outcomes have the potential to predict postoperative individual kidney function.

Prediction of perioperative outcomes following minimally invasive partial nephrectomy: role of the R.E.N.A.L nephrometry score.

OBJECTIVES: Objective characterization of renal mass anatomy facilitates treatment selection and prediction of surgical outcomes. We investigated R.E.N.A.L nephrometry score (NS) efficacy in predicting outcomes after minimally invasive nephron-sparing surgery (MINSS). METHODS: A total of 250 patients with 252 renal masses underwent MINSS by a surgeon between January 2003 and July 2011. Preoperative films were available for 181 (72 %) renal masses, which were retrospectively assigned a NS. NS was categorized as low, moderate or high, reflecting tumor complexity. Perioperative outcomes were analyzed by NS category. Outcomes for laparoscopic (LPN) versus robotic (RALPN) partial nephrectomy were compared. Multivariable regression was used to investigate predictors of postoperative complications. RESULTS: Among 181 renal masses, 128 (71 %) were managed by LPN and 53 were (29 %) by RALPN. And 103, 74 and 4 renal lesions were low, medium and high complexity, respectively. For low versus medium versus high NS, respective overall complication rate was 5.8 versus 16.0 versus 50.0 % (p = 0.01); mean warm ischemia time (WIT) was 29 versus 33 versus 39 min (p = 0.02); and transfusion rate was 5/103 (4.8 %) versus 6/74 (8.1 %) versus 1/4 (25 %) (p = 0.20). NS category was significantly associated with overall complication rate (p = 0.04) and Clavien grade III complication rate (p = 0.05). Nearness to the collecting system ("N") was significantly associated with overall complications (p = 0.02) and postoperative hemorrhage (p = 0.02). Postoperative outcomes for LPN versus RALPN were statistically similar across all categories. CONCLUSIONS: R.E.N.A.L NS is predictive of overall complications and WIT during MINSS. Our data also suggest that "N" score may be used as a single predictor of overall complications and postoperative hemorrhage following MINSS.

Comparison between magnetic anchoring and guidance system camera-assisted laparoendoscopic single-site surgery nephrectomy and conventional laparoendoscopic single-site surgery nephrectomy in a porcine model: focus on ergonomics and workload profiles.

PURPOSE: To compare surgeon-assessed ergonomic and workload demands of magnetic anchoring and guidance system (MAGS) laparoendoscopic single-site surgery (LESS) nephrectomy with conventional LESS nephrectomy in a porcine model. METHODS: Participants included two expert and five novice surgeons who each performed bilateral LESS nephrectomy in two nonsurvival animals using either the MAGS camera or conventional laparoscope. Task difficulty and workload demands of the surgeon and camera driver were assessed using the validated National Aeronautics and Space Administration Task Load Index (NASA-TLX) questionnaire. Surgeons were also asked to score 6 parameters on a Likert scale (range 1=low/easy to 5=high/hard): procedure-associated workload, ergonomics, technical challenge, visualization, accidental events, and instrument handling. Each step of the nephrectomy was also timed and instrument clashing was quantified. RESULTS: Scores for each parameter on the Likert scale were significantly lower for MAGS-LESS nephrectomy. Mean number of internal and external clashes were significantly lower for the MAGS camera (p<0.001). Mean task times for each procedure were shorter for experts than for novices, but this was not statistically significant. NASA-TLX workload ratings by the surgeon and camera driver showed that MAGS resulted in a significantly lower workload than the conventional laparoscope during LESS nephrectomy (p<0.05). CONCLUSIONS: The use of the MAGS camera during LESS nephrectomy lowers the task workload for both the surgeon and camera driver when compared to conventional laparoscope use. Subjectively, it appears to also improve surgeons' impressions of ergonomics and technical challenge. Pending approval for clinical use, further evaluation in the clinical setting is warranted.

Management of stones in abnormal situations.

Stones in abnormal situations present a management conundrum to the urologist. Many of these situations are relatively rare and literature is scanty on the appropriate management. We review the current literature on the management of stones in the setting of pregnancy, calyceal diverticulum, urinary diversions, pelvic kidneys, transplant kidneys, autosomal dominant polycystic kidney disease, horseshoe kidneys, and other renal anomalies. The aims of treatment are complete stone-free status. The modality of treatment should be individualized to the size and location of stone and type of abnormal situation confronted.

Novel iron oxide microparticles used to render stone fragments paramagnetic: assessment of toxicity in a murine model.

PURPOSE: We developed novel peptide coated iron oxide supraparamagnetic microparticles that bind to calcium stones, allowing for extraction of these stones with magnetic tools. Urothelial and fibroblast cell lines show minimal to no toxicity when exposed to the particles. Before clinical evaluation, assessment of the in vivo systemic toxicity of the microparticles was required. This was studied in a murine model. MATERIALS AND METHODS: A total of 64 mice were exposed to different concentrations of microparticles (0.5, 1 or 5 mg/dl) intravesically or intravenously via the tail vein. Mice were sacrificed at different intervals (days 1, 3, 28 and 84). Representative samples from the brain, lung, heart, kidney and liver were evaluated histologically at each time point. The tissue distribution pattern of the particles and any degree of inflammation was noted by a clinical pathologist. Liver function tests were also performed at similar intervals. RESULTS: All mice survived until the assigned end point and appeared healthy after exposure to microparticles. In the bladder installation group no particles were seen in any organ regardless of the particle concentration instilled. In the intravenous instillation group there was tissue distribution in the liver and to a lesser extent in the lung. There was mild inflammation in the liver and lung, which was dose dependent. CONCLUSIONS: Novel iron oxide supraparamagnetic microparticles used to render stone fragments paramagnetic in the urinary collecting system did not appear to cross intact urothelial membranes. When introduced systemically, they led to minimal inflammatory changes, predominantly in the liver and lung. Additional long-term studies are required.

Laparoendoscopic single-site (LESS) pyeloplasty for horseshoe ureteropelvic junction obstruction.

BACKGROUND AND OBJECTIVE: Pyeloplasty in horseshoe kidneys can be challenging due to aberrant vasculature, renal malrotation, and ectopic location. Fewer than 20 cases of minimally invasive (MIS) pyeloplasty in horseshoe kidneys have been reported in the literature to date. We herein report the first 2 cases of laparoendoscopic single-site (LESS) pyeloplasty for UPJ obstruction in horseshoe kidneys. METHODS: Two patients with symptomatic ureteropelvic junction obstruction in horseshoe kidneys were treated with an Anderson-Hynes LESS pyeloplasty. This was performed using three 5-mm trocars through a single umbilical incision, plus an accessory 3-mm port at the anterior axillary line to facilitate suturing and subsequent drain placement. RESULTS: Both patients had BMI <23. The operative times were 204 minutes and 171 minutes. Blood loss was negligible, and no intraoperative complications occurred. To date, 9-month renography for patient 1 demonstrates stable renal function and unobstructed drainage. After stent removal, patient 2 was asymptomatic. CONCLUSION: In experienced hands, LESS reconstructive techniques are applicable to complex renal anomalies. LESS pyeloplasty for UPJ obstruction associated with horseshoe kidneys is feasible, safe, and effective in select patients.

Tadalafil for prevention of renal dysfunction secondary to renal ischemia.

INTRODUCTION: Growing evidence suggests that phosphodiesterase-5 inhibitors may mitigate ischemia-related renal damage through multiple mechanisms. We evaluated the role of tadalafil in renal function preservation during experimentally induced ischemia/reperfusion injury (IRI) in a solitary kidney porcine model. MATERIALS AND METHODS: Ten adult female pigs underwent left laparoscopic nephrectomy followed by a 1 week recovery period. They were then randomized to tadalafil versus no treatment prior to cross-clamping the contralateral renal hilum for 90 minutes. The experimental group received 40 mg tadalafil in two equally divided doses, 12 hours before and just prior to surgery. Serum creatinine for each animal was obtained just prior to ischemia induction (D0) and at days 1, 3 and 7 following hilar occlusion. Median creatinine at each time point was compared between groups using the Kruskal-Wallis test. RESULTS: Median serum creatinine at D0 was significantly lower in the tadalafil group (after two doses of tadalafil) (123.8 µmol/L versus 168.0 µmol/L, p = 0.009). As expected, median creatinine for each group rose significantly on D1 (p = 0.04 for each). Median creatinines following hilar occlusion at D1, D3 and D7, however, were not significantly different between groups. CONCLUSIONS: In this porcine model, administration of perioperative tadalafil improves preoperative renal function, but it does not appear to mitigate ischemia/ reperfusion injury from hilar occlusion.

In vitro comparison of prototype magnetic tool with conventional nitinol basket for ureteroscopic retrieval of stone fragments rendered paramagnetic with iron oxide microparticles.

PURPOSE: We developed a prototype magnetic tool for ureteroscopic extraction of magnetized stone particles. We compared its efficiency for retrieving magnetized calcium oxalate monohydrate stone particles with that of a conventional nitinol basket from the pelvi-collecting system of a bench top ureteroscopic simulator. MATERIALS AND METHODS: Iron oxide microparticles were successfully bound to 1 to 1.5, 1.5 to 2 and 2 to 2.5 mm human calcium oxalate monohydrate stones. Several coated fragments of each size were implanted in the collecting system of a bench top ureteroscopic simulator. Five-minute timed stone extraction trials were performed for each fragment size using a back loaded 8Fr magnetic tool mounted on a 0.038-inch guidewire or a conventional basket. The median number of fragments retrieved per timed trial was compared for the magnetic tool vs the basket using the Mann-Whitney U test. RESULTS: For 1 to 1.5 mm fragments the median number retrieved within 5 minutes was significantly higher for the prototype magnetic tool than for the nitinol basket (9.5 vs 3.5, p = 0.03). For 1.5 to 2 mm fragments the magnetic tool was more efficient but the difference in the number of fragments retrieved was not statistically significant (9.5 vs 4.5, p = 0.19). For 2 to 2.5 mm fragments there was no difference between the instruments in the number retrieved (6 per group, p = 1.0). CONCLUSIONS: The prototype magnetic tool improved the efficiency of retrieving stone particles rendered paramagnetic that were less than 2 mm but showed no advantage for larger fragments. This system has the potential to decrease the number of small retained fragments after ureteroscopic lithotripsy.

Determining a performance envelope for capture of kidney stones functionalized with superparamagnetic microparticles.

BACKGROUND AND PURPOSE: Complete stone removal is important in upper tract stone surgery. Unfortunately, even with the latest technologic advances, current methods only achieve 50% to 80% complete clearance of upper tract stones at the time of primary treatment. Our group has explored the novel use of peptide-coated iron oxide superparamagnetic microparticles that bind to calcium stones, allowing for extraction of these stones with magnetic tools. We present analytic and numeric models that characterize stone attraction performance for feasible magnetic tool sizes and stone magnetization levels. MATERIALS AND METHODS: Magnetostatics equations are applied to a simplified, one-dimensional scenario of a spherical target coated with a variable amount of superparamagnetic particles, placed under the influence of a magnetic field aimed at vertical attraction (capture) of the target. Equations are parameterized in terms of (a) target size, ranging from 0.5 mm to 3 mm to represent stone sizes of interest, (b) effective magnetization per surface area delivered by the particle binding chemistry, and (c) distance to the field source. RESULTS: Target capture is predicted to be effective in the low, single-digit millimeter distance range, favoring smaller stones and then up to a practical upper limit of 3 mm diameter. Higher iron loading chemistries have a direct improvement in magnetic force and therefore increase the viability of the technique, albeit along an asymptotic trendline. CONCLUSIONS: We are able to characterize the potential for kidney stone capture via magnetic attraction. Computer-developed models show good correlation with experimental results using actual magnetized stone samples. Future research efforts can use the proposed techniques to estimate the performance impact of advanced magnetic tools and surface chemistries.

Long-term outcomes of renal tumor radio frequency ablation stratified by tumor diameter: size matters.

PURPOSE: Renal tumor size influences the efficacy of radio frequency ablation but identification of confident size cutoffs has been limited by small numbers and short followup. We evaluated tumor size related outcomes after radio frequency ablation for patients with adequate (greater than 3 years) followup. MATERIALS AND METHODS: We identified 159 tumors treated with radio frequency ablation as primary treatment. Disease-free survival was defined as the time from definitive treatment to local recurrence, detection of metastasis or the most recent imaging showing no evidence of disease. Patients were evaluated with contrast enhancing imaging preoperatively, and at 6 weeks, 6 months and at least annually thereafter. RESULTS: Median tumor size was 2.4 cm (range 0.9 to 5.4) with a median followup of 54 months (range 1.5 to 120). Renal cell carcinoma was confirmed in 72% of the 150 tumors that had pre-ablation biopsy (94%). The 3 and 5-year disease-free survival was comparable at 92% and 91% overall, and was dependent on tumor size, being 96% and 95% for tumors smaller than 3.0 cm and 79% and 79%, respectively, for tumors 3 cm or larger (p=0.001). Most failures (14 of 18) were local, either incomplete ablations or local recurrences. This is an intent to treat analysis and, therefore, includes patients ultimately found to have benign tumors, although outcomes were comparable in patients with cancer. CONCLUSIONS: Radio frequency ablation treatment success of the small renal mass is strongly correlated with tumor size. Radio frequency ablation provides excellent and durable outcomes, particularly in tumors smaller than 3 cm. Of tumors 3 cm or larger, approximately 20% will recur such that alternative treatment techniques should be considered. However, most treatment failures are local and are often successfully treated with another ablation session.

Radiofrequency ablation of incidental benign small renal mass: outcomes and follow-up protocol.

OBJECTIVE: To review our 10-year experience with radiofrequency ablation, focusing on the outcomes for the incidental benign renal tumor. Tumor ablation is an alternative minimally invasive approach for the treatment of small renal masses (SRMs), with published series appropriately emphasizing the outcomes for the renal cell carcinoma subset of treated tumors. However, just as with partial nephrectomy, approximately 20% of SRMs are benign. The intermediate- to long-term outcome of the incidentally ablated benign tumor and its appropriate follow-up protocol is unknown. METHODS: All SRMs treated with temperature-based radiofrequency ablation from 2001 to 2011 were reviewed. Of a total of 280 enhancing SRMs biopsied at radiofrequency ablation, 47 were confirmed as benign tumors. Ablation success was defined as the lack of enhancement on the initial postablation axial imaging. Recurrence was defined as tumor growth and enhancement on follow-up axial imaging. RESULTS: Of the 47 benign tumors, 32 were treated percutaneously and 15 laparoscopically. The histologic biopsy finding was angiomyolipoma in 10 and oncocytoma in 37. The median tumor size was 2 cm (range 1-3.6), and the mean follow-up was 45 months. No recurrences developed, and all lesions required only 1 treatment session. The median pre- and postoperative glomerular filtration rate was 77 mL/min/1.73 m(2) (range 39-137) and 68 mL/min/1.73 m(2) (range 36-137). The present study was limited by its retrospective nature and small sample population. CONCLUSION: Radiofrequency ablation of SRMs <3.5 cm found to be benign on concurrent biopsy can be efficaciously treated with a single treatment session. Long-term follow-up imaging might not be required if successful ablation is determined at the initial post-treatment cross-sectional imaging study.

Radiofrequency ablation versus partial nephrectomy in patients with solitary clinical T1a renal cell carcinoma: comparable oncologic outcomes at a minimum of 5 years of follow-up.

BACKGROUND: Long-term comparative outcomes for radiofrequency ablation (RFA) versus partial nephrectomy (PN) for the primary treatment of clinical T1a renal cell carcinoma (RCC) have not previously been reported. OBJECTIVE: Report comparative 5-yr oncologic outcomes for RFA versus PN in patients with clinical T1a RCC. DESIGN, SETTING, AND PARTICIPANTS: Observational single-institution cohort study, involving consecutive patients with a solitary histologically confirmed T1a RCC treated by RFA or PN and followed for a minimum of 5 yr. Those presenting with synchronous multiple, metachronous, bilateral, and/or metastatic disease, a history of hereditary RCC syndromes, a family history of RCC, and with post-treatment follow-up <5 yr were excluded from analysis. MEASUREMENTS: The Kaplan-Meier method was used to determine 5-yr overall survival (OS), cancer-specific survival (CSS), local recurrence-free survival (local RFS), overall disease-free survival (DFS), and metastasis-free survival (MFS) for RFA versus PN. Survival curves were compared using the log-rank test. A p value ≤ 0.05 was considered statistically significant. RESULTS AND LIMITATIONS: A total of 37 patients in each group met the selection criteria. The RFA cohort was significantly older and had more advanced comorbidities, but other patient characteristics were similar. For RFA versus PN, median follow-up was 6.5 yr (interquartile range [IQR]: 5.8-7.1) versus 6.1 yr (IQR: 5.4-7.3) (p = 0.68), respectively. The 5-yr OS was 97.2% versus 100% (p = 0.31), CSS was 97.2% versus 100% (p = 0.31), DFS was 89.2% versus 89.2% (p = 0.78), local RFS was 91.7% versus 94.6% (p = 0.96), and MFS was 97.2% versus 91.8% (p = 0.35), respectively. Study limitations are retrospective data analysis, loss to follow-up, limited statistical power, and limited generalizability of our data. CONCLUSIONS: In appropriately selected patients, RFA is an effective minimally invasive therapy for the treatment of cT1a RCC, yielding comparable long-term oncologic outcomes to nephron-sparing surgery.

Robot-assisted laparoendoscopic single-site pyeloplasty: technique using the da Vinci Si robotic platform.

Conventional laparoscopic dismembered pyeloplasty (LP) is an established alternative to open pyeloplasty given equivalent intermediate-term outcomes and decreased morbidity. Laparoendoscopic single-site (LESS) pyeloplasty has the potential to further decrease the morbidity of LP, while yielding superior cosmesis. It is, however, technically very challenging even with the use of an accessory port, largely because of the difficulty of intracorporeal suturing through a single umbilical incision. Application of the da Vinci robotic surgical platform to LESS pyeloplasty (R-LESS) has the potential to overcome these limitations. We describe our technique for R-LESS pyeloplasty using the da Vinci Si robot. We have found that use of the robotic system in conjunction with certain technique modifications helps to reduce the technical difficulty of LESS pyeloplasty and to shorten the physical learning curve associated with the procedure.

Rendering stone fragments paramagnetic with iron-oxide microparticles to improve the efficiency of endoscopic stone fragment retrieval.

PURPOSE OF REVIEW: Flexible ureteroscopes have allowed us to treat renal stones endoscopically through natural orifices. Unfortunately, there continues to be the problem of remnant stone fragments that continue to pose a health problem to patients with the risk of recurrent symptoms, obstruction and infection. RECENT FINDINGS: This article describes the research around a novel method of stone fragment extraction using microparticles and magnets. We explore the studies related to the efficiency of stone extraction and preliminary safety data. SUMMARY: This novel technique has the potential to improve the efficiency of stone fragment retrieval during retrograde intrarenal stone surgery, potentially improving stone-free rates of the surgery. Further research needs to be carried out before it is ready for human use.

Intra-operative erythropoietin during laparoscopic partial nephrectomy is not renoprotective.

PURPOSE: In pre-clinical studies, acute erythropoietin (EPO) administration has been shown to mitigate the deleterious effects of ischemia/reperfusion injury. We reviewed our clinical experience with intraoperative EPO administration as a potential renoprotective agent during laparoscopic partial nephrectomy (LPN). METHODS: Patients who underwent LPN at our institution between August 2008 and March 2010 received 500 IU/kg EPO 30 min prior to hilar occlusion. Those who underwent LPN between August 2006 and July 2008 without receiving EPO were selected as controls. Demographic, clinical, perioperative, and estimated glomerular filtration rate (eGFR) data were compared for the cohorts preoperatively, and during short-term (<6 months) and long-term (≥6 months) follow-up. RESULTS: Short-term eGFR was evaluable for 39 EPO and 29 controls, while long-term eGFR was evaluable for 26 EPO and 27 controls. Baseline demographic and clinical features of the cohorts were similar. For EPO versus controls, median short and long-term follow-up was 19 days versus 22 days and 10.2 months versus 11.9 months, respectively. Mean preoperative, postoperative, and % change in eGFR were statistically similar for the cohorts during short- and long-term follow-up, without and with adjustment for baseline renal function (unadjusted P-values = 0.28, 0.095, and 0.38, respectively, short term, and 0.61, 0.50, and 0.69, respectively, long term). CONCLUSIONS: In this retrospective study, a single dose of EPO prior to hilar occlusion during LPN had no added protective impact on postoperative eGFR in the short or long term. Prospective evaluation in patients with solitary kidneys may better elucidate its potential renoprotective role in this setting.