Stephen Faddegon

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.

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.

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.

First Place: 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.

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.

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.

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.

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.

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

This report suggests that laparoscopic single-site pyeloplasty of uteropelvic junction obstruction associated with horseshoe kidney is feasible, safe, and effective in select patients.