A Novel Device to Prevent Stone Fragment Migration During Percutaneous Lithotripsy: Results from an In Vitro Kidney Model.

PURPOSE: We developed a polyethylene sack (the PercSac) that fits over the shaft of a rigid nephroscope and is deployed into the collecting system to capture a stone and contain fragments during percutaneous nephrolithotomy (PCNL). We previously reported our results using the PercSac in a percutaneous cystolithopaxy model. In this study, we compare the efficiency of stone fragmentation with and without the PercSac in an anatomically correct in vitro PCNL model. MATERIALS AND METHODS: The PCNL model consisted of a human collecting system model created on a 3D printer. Ten BegoStones made in spherical molds of 2.0 cm diameter, matched for weight, were fragmented in the model using a 24F rigid nephroscope and an ultrasonic lithotripter, including five with and five without the PercSac. The total times for stone fragmentation and complete stone clearance, gross assessment of the stone-free status, and need for flexible nephroscopy to achieve a stone-free state were recorded. RESULTS: The median time for stone fragmentation was significantly shorter in the PercSac group compared with the control group (217 seconds [IQR = 169-255] vs 340 seconds [IQR = 310-356], [p = 0.028]). Likewise, the total time for complete stone clearance from the kidney was significantly shorter for the PercSac group (293 seconds [IQR = 244-347] vs 376 seconds [IQR = 375-480], [p = 0.047]). In one trial with the PercSac, residual dust remained in the kidney, while in all five trials without the PercSac small residual fragments remained. All trials without the PercSac required flexible nephroscopy with basket extraction to become stone free, while none of the trials with the PercSac required flexible nephroscopy for stone clearance. CONCLUSIONS: Ultrasonic lithotripsy using the novel PercSac stone entrapment device is more efficient and efficacious than traditional ultrasonic lithotripsy in an in vitro PCNL model. The advantage may be even more pronounced during clinical PCNL where residual fragments migrate into difficult-to-access calices. Further in vivo testing is underway.

Oncologic Efficacy of Radio Frequency Ablation for Small Renal Masses: Clear Cell vs Papillary Subtype.

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.

A novel device to prevent stone fragment migration during percutaneous lithotripsy.

PURPOSE: We developed a novel device to capture stones in vivo in an enclosed bag (PercSac) to prevent dispersion of stone fragments during percutaneous nephrolithotomy (PCNL) or cystolitholapaxy. We report on our initial feasibility trials of the PercSac device. MATERIALS AND METHODS: PercSac consists of a specially designed polyethylene bag that is fitted over the shaft of a rigid nephroscope. The bag is used to first entrap the target stone, then tighten around it to allow fragmentation within the bag. Matched pairs of 10 canine bladder stones (2.5 cm maximum diameter) were fragmented in a human bladder model using the CyberWand (Olympus America, Inc.), and the procedure was assessed for markers of efficiency and effectiveness. RESULTS: Median time to entrap the stone within the PercSac was 67 seconds (range 51-185 sec). Median time for stone fragmentation was significantly shorter with the PercSac than without (182.0 sec [range 108-221] vs 296.5 sec [range 226-398], P=0.004). Overall, however, there was no significant difference in the total time to entrap and fragment the stones between the two groups. A stone-free state was not achieved for any trial without the PercSac, while 9 of 10 trials with the PercSac resulted in a stone-free state. CONCLUSIONS: Use of the PercSac in conjunction with stone fragmentation has the potential to reduce the occurrence of residual fragments after PCNL or cystolitholapaxy. Further in vitro testing in a kidney model is planned.

Evaluation of anatomic and morphologic nomogram to predict malignant and high-grade disease in a cohort of patients with small renal masses.

OBJECTIVE: To evaluate a nomogram using the RENAL Nephrometry Score (RENAL-NS) that was developed to characterize masses as benign vs. malignant and high vs. low grade in our patients with small renal masses treated with partial nephrectomy (PN). The nomogram was previously developed and validated in patients with widely variable tumor sizes. MATERIALS AND METHODS: Retrospective review of PN performed between 1/2003 and 7/2011. Imaging was reviewed by a urologic surgeon for RENAL-NS. Final pathology was used to classify tumors as benign or malignant and low (I/II) or high (III/IV) Fuhrman grade. Patient age, gender, and RENAL score were entered into the nomogram described by Kutikov et al. to determine probabilities of cancer and high-grade disease. Area under the curve was determined to assess agreement between observed and expected outcomes for prediction of benign vs. malignant disease and for prediction of high- vs. low-grade or benign disease. RESULTS: A total of 250 patients with 252 masses underwent PN during the study period; 179/250 (71.6%) had preoperative imaging available. RENAL-NS was assigned to 181 masses. Twenty-two percent of tumors were benign. Eighteen percent of tumors were high grade. Area under the curve was 0.648 for predicting benign vs. malignant disease and 0.955 for predicting low-grade or benign vs. high-grade disease. CONCLUSIONS: The RENAL-NS score nomogram by Kutikov does not discriminate well between benign and malignant disease for small renal masses. The nomogram may potentially be useful in identifying high-grade tumors. Further validation is required where the nomogram probability and final pathologic specimen are available.

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. .

Renal function after laparoendoscopic single site pyeloplasty.

PURPOSE: Outcomes after laparoendoscopic single site pyeloplasty are limited to small cohort studies with short-term followup. We evaluated the clinical and renal function outcomes of what to our knowledge is the largest laparoendoscopic single site pyeloplasty cohort to date with a mean followup of 12 months. MATERIALS AND METHODS: Consecutive patients diagnosed with symptomatic ureteropelvic junction obstruction who underwent robotic or conventional laparoendoscopic single site pyeloplasty were entered into the study. Patient demographics, and preoperative and postoperative renal function outcomes were recorded. Diuretic renogram was performed after stent removal, at 6 months and yearly thereafter. RESULTS: The cohort included 31 conventional and 22 robotic laparoendoscopic single site pyeloplasties. Four laparoendoscopic single site surgeries (7.8%) were converted to another procedure due to failure to progress. Mean ± SD followup was 12.1 ± 10.7 months and 22 patients had at least 12 months of followup. No intraoperative complications occurred. Complications developed postoperatively in 11 patients (21%), of which 9 were Clavien grade 3 or greater. Preoperative symptoms resolved in 49 of 51 cases (96%). Severe obstruction (half-time greater than 20 minutes) was seen in 32 of 44 patients (73%) at presentation and obstruction resolved (half-time 20 minutes or less) in 41 (93%). Mean preoperative and postoperative half-time was 24.6 ± 13.4 and 8.3 ± 4.1 minutes, respectively, for an improvement of 16.3 ± 12.3 minutes (p <0.01). CONCLUSIONS: Laparoendoscopic single site pyeloplasty is safe and efficacious. The laparoscopic and robotic techniques provide excellent outcomes in terms of symptomatic relief and radiographic resolution of obstruction.

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.

Renal oxygenation during partial nephrectomy: a comparison between artery-only occlusion versus artery and vein occlusion.

BACKGROUND AND PURPOSE: During partial nephrectomy (PN), artery-only (AO) occlusion may mitigate ischemia/reperfusion injury because of retrograde venous flow. Using digital light processing-hyperspectral imaging (DLP(®)-HSI), we compared renal oxygenation during AO vs artery and vein (AV) occlusion in patients undergoing PN. PATIENTS AND METHODS: Thirty-seven patients who were undergoing complex open PN (median R.E.N.A.L. nephrometry of 8) at our institution underwent renal oxygenation assessment using DLP-HSI. Percent renal parenchymal oxyhemoglobin (%HbO2) during AO vs AV occlusion was recorded and its correlation with postoperative estimated glomerular filtration rate (eGFR) was investigated using Pearson correlation. AO and AV occlusion was performed in 12 and 25 patients, respectively. RESULTS: Comparing AO vs AV, mean ischemia time was 41 vs 35 minutes (P=0.02). The %HbO2 at baseline was 73.6% vs 71% (P=0.23). After hilar occlusion, %HbO2 quickly reached an "ischemic plateau" in both groups, with mean ischemic %HbO2 measures of 59.7% vs 62.2% (P=0.19). In the AV group, a lower mean ischemic %HbO2 was associated with lower eGFR at the most recent follow-up (r=0.46, P=0.02) and remained significant on multivariable analysis (odds ratio 2.31; 95% confidence interval 0.29-4.32; P=0.03). CONCLUSIONS: In this pilot clinical study, renal oxygenation profiles during PN as assessed by DLP-HSI were similar for AO vs AV occlusion. Significant retrograde venous oxygen delivery using an AO occlusion technique could not be demonstrated. There was also no renal functional advantage for AO occlusion in this population of difficult PN where prolonged ischemia times may have mitigated any advantage. Further study in cases with shorter ischemia times is warranted.

Laparoendoscopic single site (LESS) in vivo suturing using a magnetic anchoring and guidance system (MAGS) camera in a porcine model: impact on ergonomics and workload.

OBJECTIVE: To compare the ergonomics and workload of the surgeon during single-site suturing while using the magnetic anchoring and guidance system (MAGS) camera vs a conventional laparoscope. METHODS: Seven urologic surgeons were enrolled and divided into an expert group (n=2) and a novice group (n=5) according to their laparoendoscopic single-site (LESS) experience. Each surgeon performed 2 conventional LESS and 2 MAGS camera-assisted LESS vesicostomy closures in a porcine model. A Likert scale (scoring 1-5) questionnaire assessing workload, ergonomics, technical difficulty, visualization, and needle handling, as well as a validated National Aeronautics and Space Administration Task Load Index (NASA-TLX) questionnaire were used to evaluate the tasks and workloads. RESULTS: MAGS LESS suturing was universally favored by expert and novice surgeons compared with conventional LESS in workload (3.4 vs 4.2), ergonomics (3.4 vs 4.4), technical challenge (3.3 vs 4.3), visualization (2.4 vs 3.3), and needle handling (3.1 vs 3.9 respectively; P<.05 for all categories). Surgeon NASA-TLX assessments found MAGS LESS suturing significantly decreased the workload in physical demand (P=.004), temporal demand (P=.017), and effort (P=.006). External instrument clashing was significantly reduced in MAGS LESS suturing (P<.001). The total operative time of MAGS LESS suturing was comparable to that of conventional LESS (P=.89). CONCLUSION: MAGS camera technology significantly decreased surgeon workload and improved ergonomics. Nevertheless, LESS suturing and knot tying remains a challenging task that requires training, regardless of which camera is used.

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.

Does renal mass ablation provide adequate long-term oncologic control?

Renal ablation (RA) is no longer used exclusively in patients with limited life expectancy. There are few studies reporting a minimum follow-up of 5 years. Biases and discrepancies within the literature are abundant. The outcomes of any series must be interpreted in the context of median follow-up time, reported tumor characteristics, ablation technique and training background of the practitioner, and the definition of tumor recurrence. The long-term oncologic efficacy of radiofrequency ablation (RFA) and cryoablation appear similar, although the percutaneous RFA technique may necessitate reablation in more cases. RA is associated with slightly higher rates of local recurrence compared to surgical excision.

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.

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.