Clinical applications of robotic surgery platforms: a comprehensive review.

Robotic surgery has expanded globally across various medical specialties since its inception more than 20 years ago. Accompanying this expansion were significant technological improvements, providing tremendous benefits to patients and allowing the surgeon to perform with more precision and accuracy. This review lists some of the different types of platforms available for use in various clinical applications. We performed a literature review of PubMed and Web of Science databases in May 2023, searching for all available articles describing surgical robotic platforms from January 2000 (the year of the first approved surgical robot, da Vinci® System, by Intuitive Surgical) until May 1st, 2023. All retrieved robotic platforms were then divided according to their clinical application into four distinct groups: soft tissue robotic platforms, orthopedic robotic platforms, neurosurgery and spine platforms, and endoluminal robotic platforms. Robotic surgical technology has undergone a rapid expansion over the last few years. Currently, multiple robotic platforms with specialty-specific applications are entering the market. Many of the fields of surgery are now embracing robotic surgical technology. We review some of the most important systems in clinical practice at this time.

Management of Residual or Recurrent Disease Following Thermal Ablation of Renal Cortical Tumors.

Management of residual or recurrent disease following thermal ablation of renal cortical tumors includes surveillance, repeat ablation, or surgical extirpation. We present a multicenter experience with regard to the management of this clinical scenario. Prospectively maintained databases were reviewed to identify 1265 patients who underwent cryoablation (CA) or radiofrequency ablation (RFA) for enhancing renal masses. Disease persistence or recurrence was classified into one of the three categories: (i) residual disease in ablation zone; (ii) recurrence in the ipsilateral renal unit; and (iii) metastatic/extra-renal disease. Seventy seven patients (6.1%) had radiographic evidence of disease persistence or recurrence at a median interval of 13.7 months (range, 1-65 months) post-ablation. Distribution of disease included 47 patients with residual disease in ablation zone, 29 with ipsilateral renal unit recurrences (all in ablation zone), and one with metastatic disease. Fourteen patients (18%) elected for surveillance, and the remaining underwent salvage ablation (n = 50), partial nephrectomy (n = 5), or radical nephrectomy (n = 8). Salvage ablation was successful in 38/50 (76%) patients, with 12 failures managed by observation (3), tertiary ablation (6), and radical nephrectomy (3). At a median follow-up of 28 months, the actuarial cancer-specific survival and overall survival in this select cohort of patients was 94.8 and 89.6%, respectively.

Comparison of temperature change and resulting ablation size induced by a 902-928 MHz and a 2450 MHz microwave ablation system in in-vivo porcine kidneys.

INTRODUCTION: Microwave ablation (MWA) uses heat to ablate undesired tissue. Development of pre-planning algorithms for MWA of small renal masses requires understanding of microwave-tissue interactions at different operating parameters. The objective of this study was to compare the performance of two MWA systems in in-vivo porcine kidneys. METHODS: Five ablations were performed using a 902-928 MHz system (24 W, 5 min) and a 2450 MHz system (180 W, 2 min). Nonlinear regression analysis of temperature changes measured 5 mm from the antenna axis was completed for the initial 10 s of ablation using the power equation ΔT=atb and after the inflection point using an exponential equation. Thermal damage was calculated using the Arrhenius equation. Long and short axis ablation diameters were measured. RESULTS: The average 'a' varied significantly between systems (902-928 MHz: 0.0299 ± 0.027, 2450 MHz: 0.1598 ± 0.158), indicating proportionality to the heat source, but 'b' did not (902-928 MHz: 1.910 ± 0.372, 2450 MHz: 2.039 ± 0.366), signifying tissue type dependence. Past the inflection point, average steady-state temperature increases were similar between systems but reached more quickly with the 2450 MHz system. Complete damage was reached at 5 mm for both systems. The 2450 MHz system produced significantly larger short axis ablations (902-928 MHz: 2.40 ± 0.54 cm, 2450 MHz: 3.32 ± 0.41cm). CONCLUSION: The 2450 MHz system achieved similar steady state temperature increases compared to the 902-928 MHz system, but more quickly due to higher output power. Further investigations using various treatment parameters and precise thermal sensor placement are warranted to refine equation parameters for the development of an ablation model.

Image guided radiofrequency ablation for small renal masses.

The diagnosis of incidental small renal masses (SRM) has increased during the past two decades secondary to the increased use of various abdominal imaging modalities. In the past decade there has been a shift from radical nephrectomy to nephron sparing surgery techniques where partial nephrectomy has become the standard of care. Thermal ablation (TA) modalities such as freezing or heating delivered percutaneously for the treatment of small renal masses (SRM) is now offered in many Institutions as a treatment option. Clinical guidelines have indicated that TA is appropriate for select patients that are medically high risk or elderly. In our institution and in select centers, TA is discussed and often offered for all patients with SRM as equivalent treatment without respect to age or co-morbidities. As provider experience improves and long-term outcome studies become available, TA is becoming increasingly accepted as a potential new standard of care for solid SRM. This review will highlight the role of image guided radiofrequency ablation (RFA) techniques and their application focusing on the different imaging modalities for RFA application which, most commonly, include percutaneous (Magnetic Resonance Imaging (MRI) and computerized tomographic (CT). Our aim is to summarize those studies along with long term follow up.

Impressive Performance: New Disposable Digital Ureteroscope Allows for Extreme Lower Pole Access and Use of 365 µm Holmium Laser Fiber.

BACKGROUND: Since the development of the first flexible ureteroscope, in 1964, technological advances in image quality, flexibility, and deflection have led to the development of the first single-use digital flexible ureteroscope, LithoVue™ (Boston Scientific, Marlborough, MA). With respect to reusable fiber-optic and now digital ureteroscopes, there is an initial capital cost of several thousand dollars (USD) as well as, controversy regarding durability, the cost of repairs and the burdensome reprocessing steps of ureteroscopy. The single-use LithoVue eliminates the need for costly repairs, the occurrence of unpredictable performance, and procedural delays. Renal stones located in the lower pole of the kidney can be extremely challenging as extreme deflections of greater than 160° are difficult to maintain and are often further compromised when using stone treatment tools, such as laser fibers and baskets. This case describes an initial use of the LithoVue digital disposable ureteroscope in the effective treatment of lower pole calculi using a 365 µm holmium laser fiber. CASE REPORT: A 35-year-old female, with a medical history significant for chronic bacteriuria, and recurrent symptomatic culture proven urinary tract infections, underwent localization studies. Retrograde ureteropyelography demonstrated two calcifications adjoining, measuring a total of 1.4 cm, overlying the left renal shadow. Urine aspirated yielded clinically significant, >100,000, Escherichia coli and Streptococcus anginosus bacteriuria, which was felt to be originating from the left lower calix. This case used the newly FDA-approved LithoVue flexible disposable ureteroscope. The two stones were seen using the ureteroscope passed through an ureteral access sheath in the lower pole calix. A 365 µm holmium laser fiber was inserted into the ureteroscope and advanced toward the stones. There was no loss of deflection as the ureteroscope performed reproducibly. The laser was used for more than 4000 pulses at 15 W, producing mucoid debris and fragments. A 1.9F nitinol basket was, then, used to extract the fragments, and the patient was rendered stone free. Treatment success was confirmed by plain abdominal film obtained 1 week after stent removal. CONCLUSION: The LithoVue system single-use digital flexible ureteroscope provides an economical advantage over both reusable digital and fiber-optic ureteroscopes. The LithoVue system uses the enhanced image resolution of the digital complementary metal oxide semiconductor imager, similar to other reusable digital ureteroscopes, while maintaining the small ureteroscope size of a flexible fiber-optic ureteroscope, allowing for consistent and effective lower pole access. Deflection characteristics are maintained even when thicker laser fibers are passed through the working channel.

Urology residents experience comparable workload profiles when performing live porcine nephrectomies and robotic surgery virtual reality training modules.

In pursuit of improving the quality of residents' education, the Southeastern Section of the American Urological Association (SES AUA) hosts an annual robotic training course for its residents. The workshop involves performing a robotic live porcine nephrectomy as well as virtual reality robotic training modules. The aim of this study was to evaluate workload levels of urology residents when performing a live porcine nephrectomy and the virtual reality robotic surgery training modules employed during this workshop. Twenty-one residents from 14 SES AUA programs participated in 2015. On the first-day residents were taught with didactic lectures by faculty. On the second day, trainees were divided into two groups. Half were asked to perform training modules of the Mimic da Vinci-Trainer (MdVT, Mimic Technologies, Inc., Seattle, WA, USA) for 4 h, while the other half performed nephrectomy procedures on a live porcine model using the da Vinci Si robot (Intuitive Surgical Inc., Sunnyvale, CA, USA). After the first 4 h the groups changed places for another 4-h session. All trainees were asked to complete the NASA-TLX 1-page questionnaire following both the MdVT simulation and live animal model sessions. A significant interface and TLX interaction was observed. The interface by TLX interaction was further analyzed to determine whether the scores of each of the six TLX scales varied across the two interfaces. The means of the TLX scores observed at the two interfaces were similar. The only significant difference was observed for frustration, which was significantly higher at the simulation than the animal model, t (20) = 4.12, p = 0.001. This could be due to trainees' familiarity with live anatomical structures over skill set simulations which remain a real challenge to novice surgeons. Another reason might be that the simulator provides performance metrics for specific performance traits as well as composite scores for entire exercises. Novice trainees experienced substantial mental workload while performing tasks on both the simulator and the live animal model during the robotics course. The NASA-TLX profiles demonstrated that the live animal model and the MdVT were similar in difficulty, as indicated by their comparable workload profiles.

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.

Mathematical and Ex Vivo Thermal Modeling for Renal Tumor Radiofrequency Ablation with Pyeloperfusion.

BACKGROUND AND PURPOSE: Radiofrequency ablation (RFA) is an effective technique for the treatment of patients with small renal tumors, although it is often limited to tumors at least 2 cm from the renal pelvis or ureter. Retrograde pyeloperfusion (PPF) of the pelvis with cold saline during RFA may protect the pelvis and ureter. We designed a mathematical and ex vivo model of RFA to investigate the effects of PPF. METHODS: Our theoretical model uses heat transfer principles simplifying the RFA probe to a heat-emitting cylinder within a material. In the ex vivo model, an RFA probe was placed 18 mm from the pelvis in porcine kidneys and with temperature probes on either side of the RFA probe. Control trials with no PPF were compared with either cold saline (2°C), warm saline (38°C), or antifreeze (-20°C) pumped into the renal calix at a rate of 60 mL/min. Ablated volumes were measured and confirmed histologically. RESULTS: The average steady state temperatures at each probe were highest with no PPF, followed by warm saline, cold saline, then antifreeze. Compared with no PPF, temperatures were significantly (P<0.05) colder with warm saline (-8.4°C), cold saline (-18°C), and significantly colder at the calix (warm -14°C, cold -27°C). While RFA output a constant voltage, significantly lower resistances in warm (171Ω) and cold (124Ω) PPF vs no PPF (363Ω) translated to significantly greater power outputs in warm (40 W) and cold (42 W) vs no PPF (14 W). The ablated volumes were significantly higher in warm saline (2.3 cm(3)) vs cold saline (0.84 cm(3)) and no PPF (1.1 cm(3)). Mathematical modeling produced a predictive temperature curve with R2=0.44. CONCLUSION: PPF lowers temperatures throughout the entire kidney during RFA, most notably near the collecting system and is dependent on the temperature of the liquid used. In addition, PPF may cause less charring of the tissue around the probe resulting in lower resistance and higher power outputs.

Factors associated with diagnostic accuracy when performing a preablation renal biopsy.

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.

Long-term oncologic outcomes following radiofrequency ablation with real-time temperature monitoring for T1a renal cell cancer.

OBJECTIVE: Few studies report long-term follow-up of renal cancer treated by radiofrequency ablation (RFA), thus limiting the comparison of this modality to well-established long-term follow-up series of surgically resected renal masses. Herein, we report long-term oncologic outcomes of renal cancer treated with RFA in a single institution. METHODS AND MATERIALS: We retrospectively reviewed patients treated between November 2001 and October 2012 with laparoscopic-guided or computed tomography-guided RFA. All treatments were performed with real-time thermometry ensuring target ablation temperature (>60°C) was adequately reached. Only patients with biopsy-confirmed T1a-category cancer and a follow-up period>48 months were included in our analysis. Follow-up included office visits, laboratory work, and periodic contrast-enhanced imaging. Survival was calculated using the Kaplan-Meier analysis. Overall complications were reported using the Clavien-Dindo scale. RESULTS: Of 434 RFA cases, 53 treatments in 50 patients met the inclusion criteria. Of these, 29 were treated with computed tomography-guided RFA and 24 with laparoscopic-guided RFA. The mean follow-up interval was 65.6 months (48.5-120.2), and the mean renal mass size was 2.3 cm (0.3-4.0). There were 4 (7.5%) local recurrences and 1 case of distant metastases with no local recurrence. The 5-year overall survival was 98%, cancer-specific survival was 100%, and recurrence-free survival was 92.5%. The complication rate was 26.4%, which included 71% of Clavien-Dindo grade I and 29% of grade II. Mean estimated glomerular filtration rate preoperatively and at the most recent follow-up visit was 77 and 66 ml/min, respectively. CONCLUSIONS: When performed on selected patients, while monitoring real-time temperatures to ensure adequate treatment end points, RFA offers favorable long-term oncologic outcomes approaching those reported for partial nephrectomy.

Assessment of virtual reality robotic simulation performance by urology resident trainees.

OBJECTIVES: To examine resident performance on the Mimic dV-Trainer (MdVT; Mimic Technologies, Inc., Seattle, WA) for correlation with resident trainee level (postgraduate year [PGY]), console experience (CE), and simulator exposure in their training program to assess for internal bias with the simulator. DESIGN: Residents from programs of the Southeastern Section of the American Urologic Association participated. Each resident was scored on 4 simulator tasks (peg board, camera targeting, energy dissection [ED], and needle targeting) with 3 different outcomes (final score, economy of motion score, and time to complete exercise) measured for each task. These scores were evaluated for association with PGY, CE, and simulator exposure. SETTING: Robotic skills training laboratory. PARTICIPANTS: A total of 27 residents from 14 programs of the Southeastern Section of the American Urologic Association participated. RESULTS: Time to complete the ED exercise was significantly shorter for residents who had logged live robotic console compared with those who had not (p = 0.003). There were no other associations with live robotic console time that approached significance (all p ≥ 0.21). The only measure that was significantly associated with PGY was time to complete ED exercise (p = 0.009). No associations with previous utilization of a robotic simulator in the resident's home training program were statistically significant. CONCLUSIONS: The ED exercise on the MdVT is most associated with CE and PGY compared with other exercises. Exposure of trainees to the MdVT in training programs does not appear to alter performance scores compared with trainees who do not have the simulator.

Small renal mass biopsy--how, what and when: report from an international consensus panel.

To discuss the use of renal mass biopsy (RMB) for small renal masses (SRMs), formulate technical aspects, outline potential pitfalls and provide recommendations for the practicing clinician. The meeting was conducted as an informal consensus process and no scoring system was used to measure the levels of agreement on the different topics. A moderated general discussion was used as the basis for consensus and arising issues were resolved at this point. A consensus was established and lack of agreement to topics or specific items was noted at this point. Recommended biopsy technique: at least two cores, sampling different tumour regions with ultrasonography being the preferred method of image guidance. Pathological interpretation: 'non-diagnostic samples' should refer to insufficient material, inconclusive and normal renal parenchyma. For non-diagnostic samples, a repeat biopsy is recommended. Fine-needle aspiration may provide additional information but cannot substitute for core biopsy. Indications for RMB: biopsy is recommended in most cases except in patients with imaging or clinical characteristics indicative of pathology (syndromes, imaging characteristics) and cases whereby conservative management is not contemplated. RMB is recommended for active surveillance but not for watchful-waiting candidates. We report the results of an international consensus meeting on the use of RMB for SRMs, defining the technique, pathological interpretation and indications.

Emerging needle ablation technology in urology.

PURPOSE OF REVIEW: Thermal ablation of urologic tumors in the form of freezing (cryoablation) and heating (radiofrequency ablation) have been utilized successfully to treat and ablate soft tissue tumors for over 15 years. Multiple studies have demonstrated efficacy nearing that of extirpative surgery for certain urologic conditions. There are technical limitations to their speed and safety profile because of the physical limits of thermal diffusion. RECENT FINDINGS: Recently, there has been a desire to investigate other forms of energy in an effort to circumvent the limitations of cryoblation and radiofrequency ablation. This review will focus on three relatively new energy applications as they pertain to tissue ablation: microwave, irreversible electroporation, and water vapor. High-intensity-focused ultrasound nor interstitial lasers are discussed, as there have been no recently published updates. SUMMARY: Needle and probe-based ablative treatments will continue to play an important role. As three-dimensional imaging workstations move from the advanced radiologic interventional suite to the operating room, surgeons will likely still play a pivotal role in the +-application of these probe ablative devices. It is essential that the surgeon understands the fundamentals of these devices in order to optimize their application.

Assessment of robotic simulation by trainees in residency programs of the Southeastern Section of the American Urologic Association.

OBJECTIVES: To assess the Southeast Section of the American Urological Association (SESAUA) trainee exposure to and thoughts on robotic simulation. DESIGN: Questionnaire-based study of SESAUA residency trainees to determine their access to robotic simulation, live robotic experience to date, and opinion regarding the adequacy of current robotic training. SETTING: Three trainees from each SESAUA training program were invited to Orlando, Florida for a formal 2-day robotic training course. Day 1 was a 3-component didactic session. Day 2 involved faculty directing the trainees in set tasks on a live porcine model for 4 hours and another 4 hours on the Mimic dV-Trainer (Mimic Technologies, Inc, Seattle, WA) for directed exercises. PARTICIPANTS: Thirty-two trainees from 14 programs in the SESAUA participated in the course and filled out a 1-page, 8-item questionnaire following their simulator exposure. RESULTS: Seventeen (53.1%) trainees, including 5 urology year-3 trainees, reported never having had robotic console time. Of the trainees, 65.6% (21 of 32) had access to the Mimic dV-Trainer or Mimic "backpack" whereas 10 had no exposure to robotic simulation; 84.4% (27 of 32) felt that the simulator replicated real-life robotic console surgery and 90.6% (29 of 32) felt the simulator was helpful or would be helpful for training in their program. Trainees felt the "tubes 2" drill, which mimics a vesicourethral anastomosis, was the most difficult drill to perform. CONCLUSIONS: A majority of trainees in the SESAUA have had limited to no robotic console time. A high number of resident trainees in the SESAUA have exposure to virtual reality robotic simulation. Trainees believe that the simulator replicates real-life robotic console movements and almost all believe they would be benefit from having access to robotic simulation.

Radio-frequency ablation helps preserve nephrons in salvage of failed microwave ablation for a renal cancer in a solitary kidney.

Recurrent tumors after renal ablative therapy present a challenge for clinicians. New ablative modalities, including microwave ablation (MWA), have very limited experience in methods of retreating ablation failures. Additionally, in MWA, no long-term outcomes have been reported. In patients having local tumor recurrence, options for surveillance or surgical salvage must be assessed. We present a case to help assess radio-frequency ablation (RFA) for salvage of failed MWA. We report a 63-year-old male with a 4.33-cm renal mass in a solitary kidney undergoing laparoscopic MWA with simultaneous peripheral fiber-optic thermometry (Lumasense, Santa Clara, CA, USA) as primary treatment. Follow-up contrast-enhanced computed tomography (CT) scan was performed at 1 and 4.3 months post-op with failure occurring at 4.3 months as evidenced by persistent enhancement. Subsequently, a laparoscopic RFA (LRFA) with simultaneous peripheral fiber-optic thermometry was performed as salvage therapy. Clinical and radiological follow-up with a contrast-enhanced CT scan at 1 and 11 months post-RFA showed no evidence of disease or enhancement. Creatinine values pre-MWA, post-MWA, and post-RFA were 1.01, 1.14, and 1.17 mg/ml, respectively. This represents a 15% decrease in estimated glomerular filtration rate (eGFR) (79 to 67 ml/min) post-MWA and no change in eGFR post-RFA. Local kidney tumor recurrence often requires additional therapy and a careful decisionmaking process. It is desirable not only to preserve kidney function in patients with a solitary kidney or chronic renal insufficiency, but also to achieve cancer control. We show the feasibility of RFA for salvage treatment of local recurrence of a T1b tumor in a solitary kidney post-MWA.

Ablative therapies for small renal tumours.

Improvements in imaging technology have resulted in an increase in detection of small renal masses (SRMs). Minimally invasive ablation modalities, including cryoablation, radiofrequencey ablation, microwave ablation and irreversible electroporation, are currently being used to treat SRMs in select groups of patients. Cryoablation and radiofrequency ablation have been extensively studied. Presently, cryoablation is gaining popularity because the resulting ice ball can be visualized easily using ultrasonography. Tumour size and location are strong predictors of outcome of radiofrequency ablation. One of the main benefits of microwave ablation is that microwaves can propagate through all types of tissue, including desiccated and charred tissue, as well as water vapour, which might be formed during the ablation. Irreversible electroporation has been shown in animal studies to affect only the cell membrane of undesirable target tissues and to spare adjacent structures; however, clinical studies that depict the efficacy and safety of this treatment modality in humans are still sparse. As more experience is gained in the future, ablation modalities might be utilized in all patients with tumours <4 cm in diameter, rather than just as an alternative treatment for high-risk surgical patients.

Renal volumetric analysis: a new paradigm in renal mass treatment assessment.

UNLABELLED: Abstract Background and Purpose: Multiple renal volumetric assessment studies have correlated parenchymal volume with the glomerular filtration rate. The objective of this study was to compare renal volumes before and after treatment of renal masses with either partial nephrectomy or radiofrequency ablation (RFA). PATIENTS AND METHODS: We reviewed our prospectively collected database of patients with renal masses who were treated between November 2001 and January 2011 with robot-assisted laparoscopic partial nephrectomy (RALPN), laparoscopic RFA (LRFA), or CT-guided percutaneous RFA (CTRFA). Digital Imaging and Communications in Medicine CT imaging data were analyzed in an open-source viewer. Volumetric calculations were used to measure the normal, enhancing bilateral renal parenchyma and tumor volumes. Normal parenchymal volume loss was compared among treatments. RESULTS: There were 96 patients (68 men) with an average age of 68.0 (36-84) years who met our inclusion criteria. The average tumor diameter, tumor volume, and nephrometry score (NS) was 3.5 cm, 32.0 cm(3), and 7.1 in RALPN (n=26), 2.6 cm, 9.8 cm(3), and 7.1 in CTRFA (n=47), and 2.9 cm, 14.3 cm(3), and 7.2 in LRFA (n=23) groups. The percent change in the operated kidney volume was similar in RALPN (-12%±15), CTRFA (-13%±16), and LRFA (-17%±18) groups. NS was the only variable in a multivariate linear regression model that correlated with the amount of volume lost in the ipsilateral kidney. CONCLUSIONS: Our retrospective volumetric analysis of renal parenchyma before and after partial nephrectomy or RFA of renal masses revealed that all treatments produce similar volume of collateral damage.

Preoperative patient counseling for diagnostic renal biopsy and complications with renal radiofrequency ablation.

PURPOSE: To identify preoperative factors associated with surgical complications and successful diagnostic renal biopsy in both laparoscopic and percutaneous radiofrequency ablation (RFA) of renal masses in order to help aid in preoperative patient counseling for renal RFA. METHODS: We reviewed our Institutional Review Board approved database from November 2001 to January 2011, containing 335 tumors treated with either laparoscopic (LRFA) or percutaneous RFA (CTRFA). Preoperative patient demographics, tumor characteristics, and intraoperative surgical data were collected along with biopsy results and clinicopathologic outcomes. RESULTS: RFA was performed on 335 renal tumors (124 LRFA, 211 CTRFA). Non-diagnostic biopsy occurred in 18 (5.5%) tumors. Of the 317 procedures performed, 121 complications occurred in 103 (30.7%) procedures. Multivariate analysis only showed CTRFA (vs LRFA) to increase the likelihood of non-diagnostic biopsy (OR 5.1, 95% CI 1.2-22, p = 0.032). Increased tumor size (p = 0.007) and synchronous ablations (p = 0.019) increased the risk for major complications, while decreased surgeon experience (p = 0.003) and tumors close to the collecting system (p = 0.005) increased the risk of any complication. CONCLUSIONS: Preoperative recommendations can be made to patients in the future. We suggest counseling patients that when undergoing RFA, percutaneous approach increases the risk of non-diagnostic biopsy, increased tumor size increases the risk of major complications, having more than 1 tumor ablated increases the risk of a major complication, and tumors close to the collecting system may increase the risk of complications.

Low biopsy volume in ureteroscopy does not affect tumor biopsy grading in upper tract urothelial carcinoma.

OBJECTIVES: Urothelial carcinomas (UC) from the upper urinary tract represent 7%-10% of all kidney malignancies. With current ureteroscopic (URS) techniques, small tissue samples are usually the only available histopathologic material for evaluation, representing a diagnostic challenge. Precision in diagnosis is essential for treatment decision making. There has been much debate as to whether tumor grade and stage found on biopsy agree with final pathology. The purpose of this study is to evaluate whether URS biopsy volume affects tumor grading and staging agreement between biopsy and nephroureterectomy (NU) specimens. MATERIALS AND METHODS: We reviewed 137 URS biopsies in 81 patients with suspected upper urinary tract UC performed from April 2002 to April 2011. Of those, 54 patients had both the URS biopsy and NU performed at our institution and were available for review. Biopsy dimensions were recorded to calculate estimated ellipsoid volume, and 2 urological pathologists independently evaluated histologic grade (ISUP/WHO 2004), (based on pleomorphism and mitosis) and depth of invasion. Statistical analysis was performed to evaluate URS biopsy and NU specimen grade and stage concordance. In addition, univariable and multivariable analyses was performed to assess the effect of biopsy volume on agreement. RESULTS: Of the 54 patients studied, low grade and high grade UC biopsy were found in 8 (15%) and 46 (85%), URS biopsies, respectively. Regarding biopsy stage, 51 (94%), 1 (2%), and 2 (4%) were stage Ta, T1, T2, respectively. Grade concordance was 92.6%, (95% CI: 82.4%-98.0%). Stage concordance was 43% (95% CI: 28.7%-55.9%). Multivariable analysis showed biopsy volume did not affect tumor assessment of grade (P = 0.81) or stage (P = 0.44). CONCLUSIONS: Histologic grade assigned on the URS biopsy sample accurately predicts histologic grade in the resected specimen (92.6%), even when the biopsy volume is small. Grading in URS biopsies provides sufficient information for clinical decision making that is independent of sample volume.