Renal Radiofrequency Ablation Research Articles

Advancing Treatment Frontiers: Radiofrequency Ablation for Small Renal Mass-Intermediate-Term Results.

Our study aims to discern the immediate and intermediate-term oncological outcomes of the patients with small renal mass and who were surgically unfit or were having a bilateral tumor and underwent radiofrequency ablation (RFA) of the mass. We retrospectively and prospectively analyzed the status of the patients who were diagnosed to have small renal masses and were biopsy-proven renal cell carcinoma (RCC) cases, who underwent RFA at our institute from the year 2013 to 2022. Patients were followed-up for 3 years. Data regarding complications were analyzed for all patients who underwent renal RFA along with the 3-year recurrence-free survival (RFS) rate. A total of 28 patients were eligible for the study based on our inclusion and exclusion criteria. Their renal function was recorded. They underwent RFA and were followed-up for a period of 3 years for RFS. Four patients out of the total had immediate complications, out of which two developed a hematoma. Three-year-follow-ups showed six recurrences, overall having 78.6% RFS. Post-procedural renal function was stable as documented by Estimated glomerular filtration rate. Oncological results of RFA in patients with small renal masses who are surgically unfit are associated with a low risk of immediate and intermediate-term deterioration of renal function.

Radiofrequency ablation for renal tumours: A retrospective study from a tertiary centre

ObjectiveThis study aimed to evaluate the safety and efficacy outcomes of percutaneous radiofrequency ablation (RFA) for localised renal cell carcinoma (RCC) in a tertiary hospital patient who remained unfit for surgical intervention. MethodsWe retrospectively analysed survival outcomes for patients with biopsy proven RCC treated by RFA at Royal Perth Hospital between September 2009 and May 2018. Complication data were gathered for all patients that underwent renal RFA along with 2- and 5-year recurrence-free survival (RFS) rate and compared the outcomes with data from previous studies. ResultsA total of 69 patients (73 procedures) were eligible for the study, and those patients had biopsy-proven RCC with a minimum of 2-year follow-up. The complication rate was 8.2% (6/73) and local recurrence rate 9.6% (7/73). Two-year RFS is 95.7% and 5-year RFS is 78.8% on a median 3.82-year follow-up (interquartile range 1.90–5.75 years). ConclusionRFA performed at our centre was found to be safe and effective with low complication rates and durable RFS in line with expectations from existing research. Our study demonstrated that RFA is an alternative modality of treatment for small renal tumours in patients unfit for surgical approach.

Colo-renal fistula following percutaneous radiofrequency ablation of a renal tumor. A case report and review of treatment options

Background: Colo-renal fistula formation is a very rare complication following percutaneous radiofrequency ablation (RFA) in the management of renal cell carcinoma. In this paper we describe the management of a patient with a left colo-renal fistula occurring after renal tumor RFA. Additionally, we present a thorough literature review of reported cases of colo-renal fistulae after percutaneous RFA to further highlight their treatment challenges. Summary: Two weeks after undergoing percutaneous RFA of an incidental 3cm left renal mass, a 67-year-old male was re-admitted to the hospital with a symptomatic colo-renal fistula. Patient ultimately failed conservative management with broad spectrum antibiotics and ureteral stent placements, and subsequently underwent segmental colonic resection and renorrhaphy, with complete renal preservation. Conclusion: Although complications after RFA of renal tumors are rare, iatrogenic colo-renal fistula formation is a significant complication requiring a multi-disciplinary approach with a trial of non-operative management prior to surgical intervention.

Possible mechanisms of renal denervation long-term cardiac effects

Background.The renin-angiotensin-aldosterone system (RAAS) plays a key role in target organ damage in arterial hypertension (HTN), initiating the development of left ventricular hypertrophy (LVH), as well as the heart and vascular wall fibrosis and remodeling. In addition, one of the mechanisms of the cardiovascular disease progression is the angiotensin II-induced inflammation.Objective.To study the changes in renin, aldosterone and high-sensitive C‑reactive protein (CRP) levels two years after sympathetic renal denervation (RDN), to compare these changes with antihypertensive efficacy of the intervention and LVH regression.Design and methods.We included 77 patients with drug-resistant hypertension in the absence of contraindications to renal denervation. All patients underwent renal radiofrequency ablation. The active renin, aldosterone and a high-sensitive CRP concentrations assessment, 24‑hour blood pressure (BP) measurement and echocardiography were performed before, at 6 months, one and two years after the intervention.Results.There was a gradual decrease in CRP levels (the difference was significant after 6 months), aldosterone (significant two years after surgical treatment), and active renin (the difference was the most pronounced after one year). At all follow-up assessments, plasma renin activity correlated with left ventricular mass. At the same time, there were no significant differences between responders and non-responders.Conclusions.RDN leads to a RAAS activity attenuation, manifested by the decrease in both renin and aldosterone and CRP, probably due to angiotensin II proinflammatory effects reduction. Given these effects are long-term, correlate with LVH degree and unrelated to the BP lowering, a direct cardioprotective effect of renal denervation should be considered.

Volume and Shape Assessment of Renal Radiofrequency Ablation Lesion

To evaluate the microscopic characteristics and quantify the volume of a radiofrequency ablation (RFA) lesion. Ten male pigs were submitted to laparoscopic RFA. An RFA needle was introduced in the lower pole of the left kidney to create a lesion expected to be a sphere of 2.0 cm diameter. The animals were followed up for 21 days. Kidneys were weighed and the volume was assessed using Scherle's method. Cavalieri's principle was used to assess the RFA volume, and sphericity was calculated to assess RFA lesion. One sample t test was used to compare RFA volume with the volume of a sphere of 2.0 cm diameter, and sphericity to hypothetical values of a sphere and an icosahedron. Fragments of RFA region were histologically evaluated. Three animals developed postoperative complications and were excluded from the analyses. There was no difference in the mean weight and volume between right and left kidneys following RFA. The mean total volume of RFA injury was 3.44 cm3. There was no difference in the RFA volume in comparison with hypothetical volumes of a sphere and an icosahedron of 2.0 cm diameter. Sphericity of the RFA injury was not similar with a sphere; however, it was similar to an icosahedron. Histology revealed areas of coagulation necrosis, fibrosis, and inflammatory mononuclear infiltration. Areas with normal tissue were also observed. The volume of injury caused by RFA was as expected and its shape was comparable with an icosahedron. Microscopic evaluation revealed areas of normal-appearing tissue.

Abstract No. 684 Imaging surveillance following radiofrequency ablation of renal cell carcinoma

The purpose of this study is to review our institution's ten-year experience with imaging surveillance following percutaneous radiofrequency ablation for spontaneous stage T1a renal cell carcinoma, and apply risk stratification based upon the post-procedure CT scan, modified renal nephrometry score, and tumor histology. All renal radiofrequency ablation procedures performed at our institution from 1/1/2005 through 7/31/2015 were reviewed, including pathology and follow-up imaging. Inclusion criteria were all cases of T1a biopsy-proven renal cell carcinoma with at least one follow-up imaging study after the post-ablation scan. Exclusion criteria were benign or indeterminate pathology, Von Hippel Lindau syndrome (VHL), no imaging follow-up available, prior thermal ablation on the same lesion, or RFA discontinued due to technical factors. Cases meeting inclusion criteria were evaluated with mRENAL Nephrometry score, tumor histology, and post-therapy CT scan. Time lag to detection was calculated for each instance of recurrence. 52 cases (in 49 patients) of T1a biopsy-proven renal cell carcinoma status post radiofrequency ablation with at least one follow-up imaging study met the criteria for inclusion. 7 cases of RCC recurrence were identified. Cases of disease recurrence had a statistically significantly higher mRENAL score (7.3 versus 6.0, two-tailed T-test p-value .0087). Recurrence was more likely in tumors with clear cell histology (5/18 versus 2/34 for other histology, Fisher exact test statistic value .0409). There were no cases of disease recurrence if the post-therapy CT scan was definitively negative. The mRENAL Nephrometry score, tumor histology, and post-therapy CT scan inform the rate of tumor recurrence following radiofrequency ablation of T1a renal cell carcinoma. These data may be incorporated into the development of surveillance strategies to yield cost savings and decrease patient radiation exposure, while maintaining surveillance effectiveness.Tabled 1Imaging Surveillance Following Radiofrequency Ablation of Renal Cell CarcinomaCharacteristics of RCC RecurrenceCase#Tumor size (cm)mRENAL scoreRCC histologyPost-RFA CTRFA to detection (days)Lag to detection (days)Size at detection (cm)Recurrence strategy13.58Clear cellIndeterminate11382433.5Surveillance23.18Clear cellNot performed76763.2Nephrectomy32.97Clear cellNot performed4584060.9Repeat RFA43.19Clear cellIndeterminate2382381.7Surveillance52.57Clear cellPositive110.3Surveillance62.77RCC NOSNot performed1861861.9Repeat RFA72.14PapillaryNot performed2712711.6Surveillance Open table in a new tab

Glomerular Loss After Renal Radiofrequency Ablation Are Comparable to 30 Minutes of Warm Ischemia.

To compare, with stereological methods, the glomerular loss in kidneys submitted to radiofrequency ablation (RFA) or warm ischemia. Twenty-six male pigs were divided into three groups. Eight animals were allocated in the sham group, which was submitted to laparoscopic dissection of the left renal hilum, without renal ischemia. Eight animals were allocated in the ischemia group, which had the left renal hilum clamped for 30 minutes under laparoscopic access. Ten animals were submitted to RFA of the left kidney lower pole, under laparoscopic visualization. Animals were euthanized 21 days after surgery, when kidneys were collected. Fragments of the upper pole of the left kidney were processed for morphometric analysis. Right kidney was used as self-controls for each animal. Glomerular volumetric density (Vv[glom]); volume-weighted glomerular volume (VWGV); and glomerular density were quantified by stereological methods and compared by Student's t-test and one-way-analysis of variance with Dunnett's post-test. Three animals in the RFA group developed postoperative complications (Urinoma/Hydronephrosis) and were excluded from the analysis. No difference was found among the kidneys submitted to RFA and warm ischemia for all parameters. However, these kidneys showed lower Vv[glom] and glomerular density when compared to its self-controls (right kidneys), and when compared to sham-operated animals (p < 0.05). No difference was observed in regards to VWGV among the groups. RFA in pigs determines a significant reduction of glomerular density in the remaining parenchyma. This alteration was comparable to that observed in kidneys submitted to 30 minutes of warm ischemia.

Safety, efficacy and predictors of local recurrence after percutaneous radiofrequency ablation of biopsy-proven renal cell carcinoma.

To evaluate the safety and efficacy of percutaneous radiofrequency ablation (RFA) for localised renal cell carcinoma (RCC) and examine potential associations between age, gender, tumour size, location, chronic kidney disease, comorbidities, learning curve and local recurrence. We retrospectively analysed survival outcomes for patients with biopsy-proven RCC treated by RFA at Westmead Hospital. Complication data were gathered from all patients that underwent renal RFA. 3 and 5year local recurrence-free (RFS), disease-free (DFS) and overall survival (OS) outcomes were reported. Univariate and multivariate analysis was used to examine each potential predictor. A total of 168 patients were eligible for the study. Forty-eight patients with biopsy-proven RCC had minimum 3-year follow-up. Our complication rate was 1.2% (2/168) and local recurrence rate 10.4% (5/48). Five-year RFS, DFS and OS were 86.8, 82.3 and 92.6% on a median 4.1-year follow-up (IQR 3.4-4.9). None of the patient or tumour-specific characteristics were associated with RFS. Radiofrequency ablation performed at our centre was a safe and effective procedure with low complication rates and durable RFS. Tumour characteristics, comorbidities and learning curve were not associated with local recurrence.

Thermo-sensitive hydrogel for preventing bowel injury in percutaneous renal radiofrequency ablation.

Percutaneous radiofrequency ablation (PRFA) has been used to ablate renal neoplasms with good outcome. However, if bowel lies adjacent to a tumor, ablation increases the risk of thermal bowel injury, and the consequences could be fatal. We describe the technique, effectiveness and safety of using thermo-sensitive hydrogel as insulation to displace the bowel away during PRFA. The study was divided into two main parts: the in vitro and in vivo studies. In in vitro study, to explore the heat insulation of hydrogel, the rabbit kidney was entirely embedded in hydrogel, and then radiofrequency ablation was performed; the temperature on the gel-air and gel-kidney interfaces was measured. In in vivo study, hydrogel of poloxamer 407, 25% concentration (w/v), was instilled into the perinephric space of 10 rabbits under CT guidance to separate the kidney from adjacent bowel before PRFA performed in the targeted parenchyma in the gel group. For the control group, PRFA was performed in similar portions of 10 rabbits without instillation of hydrogel. Some parameters were recorded such as kidney-to-bowel and electrode-to-bowel distance. Immediately after PRFA, distribution of hydrogel was evaluated and the dimension of radiofrequency ablation zone was measured; bowel thermal injury was compared between the gel and control groups by gross anatomy and histopathological examination. To assess safety, two additional follow-up groups with 10 rabbits in each were set; after PRFA, CT scan was performed every 2days; gel absorption, thermal damage and some other complications were evaluated during the period. In in vitro study, temperature was significantly lower at the gel-air than gel-kidney interface (P<.05), and the temperature gradient was positively associated with gel thickness. In in vivo study, hydrogel was instilled successfully in all rabbits in the gel group. The kidney-to-bowel and electrode-to-bowel distances were larger in the gel than control group [(1.1±0.6cm vs 0.1±0.0cm, P<.01), (1.8±0.4cm vs 0.5±0.1cm, P<.01), respectively]. The gel and control groups did not differ in size of the ablation zones (0.80±0.2cm vs 0.75±0.3cm, P>.05). Thermal injury in adjacent bowel was more serious in the control than gel group (P<.01). As for the follow-up, rabbits with gel instillation showed good condition and gel was absorbed gradually within 5days. Those rabbits with no bowel displacement by gel got significantly lower survival rate and high complication rate (P<.01). Hydrogel-dissection by means of thermo-sensitive hydrogel instillation is valuable for protecting the bowel adjacent to ablation area against thermal injury during PRFA.

Simultaneous biopsy and radiofrequency ablation of T1a renal cell carcinoma.

The goal of this study was to retrospectively evaluate the outcome, including feasibility, safety, diagnostic yield, and factors affecting the success of computed tomography fluoroscopy-guided biopsy when performed during the same procedure than radiofrequency ablation (RFA) in renal tumors strongly suspected of being T1a renal cell carcinoma (RCC). Nineteen patients (13 men, 6 women; mean age, 66.7 years) with a total of 19 suspected renal tumors (mean diameter, 1.8cm) underwent computed tomography fluoroscopy-guided biopsy during (n=6) or immediately after (n=13) RFA. All patients were strongly suspected of having RCC on the basis of patient's medical histories and/or the results of imaging investigations. All procedures were divided into diagnostic and non-diagnostic biopsies. Various variables were compared between the 2 groups using univariate analysis. In all tumors, biopsy procedures were technically feasible. No major complications were observed, except for 8 minor post-procedural bleedings. All but one tumor was completely ablated. Local recurrence in the ablation zone as well as tumor seeding in retroperitoneal fat occurred in 1 patient 8.5months after the procedure and were successfully treated with further percutaneous cryoablation. Thirteen tumors were diagnosed as RCC, whereas 6 were ultimately found to contain normal renal tissue (n=5) or connective tissue (n=1). Univariate analysis revealed that none of the variables were significantly different between the diagnostic and non-diagnostic biopsies. The performance of renal tumor biopsy and RFA in the same session is feasible and safe. Although pre-treatment pathological diagnosis would be generally desirable, simultaneous biopsy with RFA can be an option for the patients who are not amenable to pre-treatment biopsy.

1090 Glomerular volumetric density is reduced after renal radio-frequency ablation as well as after warm ischemia

1090 Glomerular volumetric density is reduced after renal radio-frequency ablation as well as after warm ischemia

Predictive factors for complete renal tumor ablation using RFA.

Radiofrequency ablation (RFA) can be used to treat renal masses in patients where surgery is preferably avoided. As tumor size and location can affect ablation results, procedural planning needs to identify these factors to limit treatment to a single session and increase ablation success. To identify factors that may affect the primary efficacy of complete renal tumor ablation with radiofrequency after a single session. Percutaneous RFA (using an impedance based system) was performed using computed tomography (CT) guidance. Fifty-two renal tumors (in 44 patients) were retrospectively studied (median follow-up, 7 months). Data collection included patient demographics, tumor data (modified Renal Nephrometry Score, histopathological diagnosis), RFA treatment data (electrode placement), and follow-up results (tumor relapse). Data were analyzed through generalized estimating equations. Primary efficacy rate was 83%. Predictors for complete ablation were optimal electrode placement (P = 0.002, OR = 16.67) and increasing distance to the collecting system (P = 0.02, OR = 1.18). Tumor size was not a predictor for complete ablation (median size, 24 mm; P = 0.069, OR = 0.47), but all tumors ≤2 cm were completely ablated. All papillary tumors and oncocytomas were completely ablated in a single session; the most common incompletely ablated tumor type was clear cell carcinoma (6 of 9). Optimal electrode placement and a long distance from the collecting system are associated with an increased primary efficacy of renal tumor RFA. These variables need to be considered to increase primary ablation success. Further studies are needed to evaluate the effect of RFA on histopathologically different renal tumors.

Renal radiofrequency ablation with pyeloperfusion.

Table S1 Postprocedural complications. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Cancer-free survival and local tumor control after impendence-based radiofrequency ablation of biopsy-proven renal cell carcinomas with a minimum of 1-year follow-up

ObjectivesThere are numerous reports describing the use of radiofrequency ablation (RFA) to treat renal cell carcinoma. Many series, however, describe heterogeneous populations, lack histologic descriptions, use various RFA systems, and indicate tumor destruction by different ablation end points. This study examined the outcomes of computed tomography–guided, impedance-based RFA of biopsy-proven renal cell carcinoma clinically staged as T1a with a minimum of 1 year of postablation follow-up. Methods and materialsThis retrospective study identified all consecutive patients who had undergone renal RFA since May 2005 at our institution. Patients without biopsy-proven renal cell carcinoma (RCCa) were excluded. Of the patients who met these criteria, evaluation was limited to patients with a minimum of 12 months of follow-up. Data collected from the patients׳ electronic medical and radiologic records included demographic data, tumor-related data, procedural details, and clinical follow-up visits. ResultsA total of 39 patients (46 lesions) met the inclusion criteria. The mean tumor diameter was 2.6cm (range: 1.2–4.0cm). The most common histologies were clear cell (n = 27) and papillary (n = 16) renal cancer. The lesion location was equally divided between upper pole (n = 16), middle pole (n = 16), and lower pole (n = 14). Overall, 83% of the tumors were exophytic. No residual or recurrent enhancing mass was identified in the ablation bed on post-RFA imaging during the mean follow-up period of 35.3 months (range: 12–83). All patients were treated in a single encounter and no lesion required a second ablation; technical success (absence of residual tumor) on the initial post-RFA imaging study was 46 of 46 (100%). Clinical success was achieved in 45 of 46 lesions (98%); residual, viable tumor was found in a pretransplant nephrectomy specimen on postprocedure day 127. The mean cancer-free survival was 36.2 months. Comparison of preablation and postablation renal function found no statistically significant change. ConclusionsThe consistent outcomes in our post-RFA imaging and clinical surveillance allow us to offer image-guided ablation to patients with T1a RCCa as a valid treatment option offering long-term cancer-free survival. Impedance-based RFA in a carefully selected patient population with T1a RCCa is a reliable treatment option, with disease-free survival rates that are comparable to partial nephrectomy.

Radiofrequency Ablation of Renal Cell Carcinoma

Thermal ablation of renal cell carcinoma (RCC) has become increasingly popular and provides many advantages over surgical resection, particularly in patients with poor renal function and in those with multiple comorbidities. Extensive experience supports the use of image-guided radiofrequency ablation (RFA) in treatment of primary RCC with a high cure rate and a low rate of complications. This article reviews the indications for thermal ablation and the risks, benefits, and complications of the procedure. Furthermore, the article describes in detail the essential steps for performing renal RFA and reviews follow-up imaging timing and interpretation.

The Application of R.E.N.A.L. Nephrometry Scoring System in Predicting the Complications After Laparoscopic Renal Radiofrequency Ablation

To investigate the clinical significance of R.E.N.A.L. nephrometry scoring system in evaluating the complications after laparoscopic radiofrequency ablation (LRFA) of renal tumors. We conducted a retrospective review of the records of all patients who underwent LRFA of renal tumors from February 2006 to March 2012 in our institution. Tumors were categorized as low (4-6), moderate (7-9), or high complexity (10-12) according to R.E.N.A.L. nephrometry score (NS), which was determined by analyzing preoperative imaging. Perioperative data were analyzed to determine the presence of complications. LRFA was performed on 170 tumors in 170 selected patients with preoperative imaging available. Mean patient age was 55.9 years (range 26 to 81), and mean tumor size was 2.8 cm (range 0.9 to 4.9). Mean NS was 6.6 (range 4 to 12). Of the total tumors, 105 (61.7%) were categorized as low-, 46 (27.1%) as moderate-, and 19 (11.2%) as high-complexity lesions. Overall, there were 21 (12.4%) complications, including 6 (3.6%) grade IIIa and 15 (8.8%) grade I-II complications. There was a significant difference in complication rates among the low- (105 patients, 0%), moderate- (46 patients, 4.3%), and high-complexity (19 patients, 100%) groups, respectively (p<0.05). NS was independently associated with a higher risk of postoperative complications (odds ratio 2.87, 95% CI 1.17-3.04, p=0.02) on multivariate analysis. The results of patients undergoing LRFA show that the R.E.N.A.L. NS is independently associated with the occurrence of complications. Therefore, the R.E.N.A.L. nephrometry scoring system is useful in predicting the complication risks of patients who undergo LRFA, and may help with surgical decision making.

Renal Denervation – A Flight of Icarus?

Since its introduction in 2008 Renal Denervation (RDN) has garnered enthusiasts among physicians, patients and the medical device industry. In December 2013 a research and consulting firm predicted a growth of the global renal denervation market in the next 6 years from approximately 3,000 procedures in 2012 up to nearly 40,000 by 2019 (representing a value of over $170 million). Even though the optimism was toned down after 5 years of trial applications of RDN (initial expectations mentioned a market on the order of a billion dollars by 2020), the hype surrounding this invasive therapy method for patients with treatment-resistant hypertension was still on the rise. This all changed in January 2014 when Medtronic announced that its pivotal SYMPLICITY HTN-3 trial failed to meet its primary efficacy endpoint. After promising data obtained from SYMPLICITY HTN-2 Medtronic’s this next trial, that included a sham-control group, was supposed to strengthen the position of RDN as an emerging leading therapy in patients with treatment resistant hypertension. Putting aside the discussions about the necessity and usefulness of a control sham treatment (according to some experts the pain caused in a number of patients by denervation reduced the validity of blinding) and differences between using ambulatory BP monitoring, home electronic BP monitoring and repeated office electronic measurement as an endpoint, SYMPLICITY HTN-3’s failure has been widely received as a major blow to the potential future worldwide deployment of RDN in the treatment of hypertension. SYMPLICITY HTN 4, HTN-India und HTN-Japan trials have been consequently called off, while previously, at the end of 2013, the EnligHTN II trial was stopped (apparently due to recruitment difficulties). Many have spelled the demise of RDN at this point even though the actual data from the SYMPLICITY HTN-3 trial still needs to be fully analysed. Some are trying to look at the bright side of recent developments now is the time to take a step back and analyse the underlying principle of this treatment method – interruption of signal transmission in the renal sympathetic nervous system. There are still some contradictory views on the longitudinal distribution of renal sympathetic nerves along renal arteries which may affect the currently advised course of RDN procedure (distal to proximal) [1]. Furthermore the radial distribution of nerves in renal artery walls, which seems to be the most important anatomic factor for intravascular RDN, has only been studied in small groups both in animal models and human cadavers [1-3]. It is widely accepted that most (up to 90%) nerves are situated within 2 mm of the lumen-intima interface [2,3]. To obtain a successful result an ablation depth of 4 mm is targeted but it is well known that some ablation related changes might extend to a depth of up to 6 mm [4], thus introducing a potential risk of irreversible injury to the artery itself. Dissections and vasospasm during ablation have been reported and well documented but there are some new reports of delayed renal artery stenosis related to RDN [5,6]. Templin et al used Optical Coherence Tomography (OCT) to document wall oedema after RDN Procedures but they have also admitted to a limitation of their results as a consequence of limited imaging depth of OCT (0.5 to 2.0 mm) [7]. In vivo monitoring of acute RDN related changes in arterial walls remains challenging. In conclusion transcatheter renal radiofrequency ablation is still not yet ready to be widely introduced into clinical practice and must be further investigated. On the other hand different methods of RDN might come into limelight, such as an intravascular ultrasound based technique, chemical trancatheter denervation with ethanol, MR-based or CT-based perirenal denevation with ethanol or an extracorporal high-intensity focused ultrasound. Despite many concerns, the future of RDN seems to be bright.

Ultrasound-Guided Transhepatic Radiofrequency Ablation of Renal Tumors: A Safe and Effective Approach

This study was designed to determine the feasibility and safety of ultrasound-guided transhepatic radiofrequency ablation (RFA) of masses in the right kidney. Between June 2001 and December 2011, 18 patients who underwent transhepatic renal RFA procedures to treat 19 tumors were retrospectively identified. Complications (Clavien-Dindo classification system) and local tumor control were evaluated for all patients. Median maximal diameter of the treated renal tumors was 1.9 (range 1.1-4.3) cm. No major complication developed during any of the procedures. No hepatic tumor seeding was identified during imaging follow-up. There was a single technical failure (5.3%). Median cross-sectional imaging follow-up was 28 (range 3-121) months. Primary technique failure (local recurrence) occurred in 1 of the 16 tumors with follow-up imaging (5.3%). Percutaneous ultrasound-guided transhepatic RFA of renal neoplasms is technically feasible, effective, and associated with a low rate of complications. The transhepatic approach may allow safe ablation of renal tumors that would otherwise be difficult to treat.

The failing effects of renal sympathetic denervation in patients with drug resistant hypertension and untreated obstructive sleep apnea

Introduction: Arterial hypertension (AHT) is a common cause of stroke, myocardial infarction, chronic heart failure and death. For patients refractory to more than 4 antihypertensive drugs renal sympathetic denervation (RDN) offers a new therapeutic approach. Our main aim was to investigate the effects of RDN in patients with and without obstructive sleep apnea (OSA). Methods: After excluding of secondary causes for AHT 40 patients (age 56±6 years; 60% male; 4,3% COPD GOLD≥2, 40% OSA, AHI mean 17/h) with resistant arterial hypertension were treated by renal radiofrequency ablation. During a 3 months follow up period the development of 24 hour means of outpatients blood pressure (BP) were assessed and correlated with patients baseline apnea-hypopnea-index (AHI) measured by polysomnography and classified by 3 cohorts. Results: After 3 months, the overall reduction in BP was 15 mmHg systolic and 9 mmHg diastolic. 30 patients showed significant reduction in 24h blood pressure evaluation (mean -17/-11mmHg). 10 patients did not respond to RDN (mean RR +7/+4mmHg). While patients without OSA (AHI <5) showed significant BP reduction (-21/-14mmHg), the reduction in those with an AHI ranging between 5 und 20 was weak (-4/-2 mmHg; r= 0,35). In contrast, BP in patients with an AHI above 20 remained unchanged or even increased (mean +4/+2 mmHg). Thus, untreated OSA is a strong predictor of RDN failure (Kruskal Wallis test, p<0,05). No intervention related complications occurred. Conclusion: Renal denervation is an effective therapeutic option for patients with arterial hypertension refractory to an extended drug regimen. Our results show, that the success in BP reduction following RDN depends on patients state free of OSA. Thus, RDN is not a tool for managing resistant AHT in untreated OSA patients.

Focal Therapy in Urology: Kidney Cancer

Focal therapy has gained attention in the treatment of small renal masses (SRM). However, its use is limited due to scarce data on long-term outcomes. The availability of such data is significantly lower as compared to the relevant data on surgery outcomes. At the same time, minimally invasive surgery has seen the development of laparoscopic nephron-sparing surgery and, recently, robot-assisted surgery. Our purpose is to review the possibilities of treatment for SMR with particular attention on focal therapy. Clinical series and comprehensive reviews support safety and mid/long-term efficacy of renal cryoablation or radiofrequency ablation. Comparative studies and meta-analysis outlined oncological inferiority against partial nephrectomy in local tumor control. For smaller and more peripheral lesions, radiofrequency ablation showed best indications than cryoablation. There are significant demographic and tumor differences between patients treated by one or another approach. The correct indication for each treatment seems to be of key importance to achieve the best oncological and functional outcome. Open partial nephrectomy remains the gold standard treatment for PMR, but laparoscopic approaches have been showing similar results.