Renal Function After CT-Guided Cryoablation of Small Renal Tumours in Patients with Solitary Kidney: An Analysis of European Multinational Prospective EuRECA Registry.

PURPOSE: Treatment of renal cell carcinoma (RCC) in patients with solitary kidneys remains challenging. The purpose of this multicentre cohort study was to explore how renal function is affected by percutaneous image-guided cryoablation in patients with solitary kidneys. MATERIAL AND METHODS: Data from the European Registry for Renal Cryoablation database were extracted on patients with RCC in solitary kidneys treated with image-guided, percutaneous cryoablation. Patients were excluded if they had multiple tumours, had received previous treatment of the tumour, or were treated with more than one cryoablation procedure. Pre- and post-treatment eGFR (within 3 months of the procedure) were compared. RESULTS: Of 222 patients with solitary kidneys entered into the database, a total of 70 patients met inclusion criteria. The mean baseline eGFR was 55.8 ± 16.8 mL/min/1.73 m2, and the mean 3-month post-operative eGFR was 49.6 ± 16.5 mL/min/1.73 m2. Mean eGFR reduction was - 6.2 mL/min/1.73 m2 corresponding to 11.1% (p = 0.01). No patients changed chronic kidney disease group to severe or end-stage chronic kidney disease (stage IV or V). No patients required post-procedure dialysis. CONCLUSION: Image-guided renal cryoablation appears to be safe and effective for renal function preservation in patients with RCC in a solitary kidney. Following cryoablation, all patients had preservation of renal function without the need for dialysis or progression in chronic kidney disease stage despite the statistically significant reduction in eGFR. LEVEL OF EVIDENCE 3: Observational study.

Radiofrequency ablation (RFA) of renal cell carcinoma (RCC): experience in 200 tumours.

OBJECTIVES: To evaluate our clinical experience with percutaneous image-guided radiofrequency ablation (RFA) of 200 renal tumours in a large tertiary referral university institution. PATIENTS AND METHODS: Image-guided RFA (ultrasonography or computed tomography [CT]) of 200 renal tumours in 165 patients from June 2004 to 2012 was prospectively evaluated. Institutional Review Board approval was granted. The treatment response and technical success were defined by absence of contrast enhancement within the tumour on contrast enhanced CT or magnetic resonance imaging. Both major and minor complications, glomerular filtration rate (GFR) before and after RFA, the management and outcomes of the complications, as well as oncological outcome were prospectively documented. Multivariate analysis was used to determine variables associated with major complications and also the percentage GFR change after RFA. The overall (OS), 5-year cancer-specific (CSS), local recurrence-free (LRFS) and metastasis-free survival (MFS) rates are presented using the Kaplan-Meier curves. RESULTS: In all, 200 tumours were RF ablated with a mean (range) tumour size of 2.9 (1-5.6) cm and the mean (range) patient age was 67.7 (21-88.6) years with a mean follow-up period of 46.1 months. The primary technical and overall technical success rate was 95.5% and 98.5%, respectively. Two independent predictors of successful RFA in a single sitting were tumour size (<3 cm) and exophytic location in multivariate logistic regression analysis. Major complications included ureteric injury (six patients), calyceal-cutaneous fistula (one), acute tubular necrosis (one) and abscess (two). Two independent predictors of ureteric injury were central location and lower pole position. Within this cohort of patients, only four patients developed significant renal function deterioration i.e. >25% decreased in GFR. In all, 161 (98%) patients of the 165 patients have preservation of renal function. Any change in renal function after RFA was not influenced by tumour factors or solitary kidney status. In our clinical series, this yielded a 5-year OS, CSS, LRFS and MFS rates of 75.8%, 97.9%, 93.5% and 87.7% respectively. CONCLUSIONS: Image-guided RFA is a safe, nephron sparing and effective treatment for small renal cell carcinoma (RCC) tumours with a low rate of recurrence and has good 5-year CSS and MFS rates.

MINI PCNL in a pediatric population.

PURPOSE: We report our initial experience of MINI percutaneous nephrolithotomy (PCNL) in a pediatric population using a miniature nephroscope through a 16F metal access sheath. METHODS: All pediatric patients who underwent PCNL from August 2007 to September 2010 using a 14F miniature nephroscope through a 16F metal access sheath for renal stone extraction were evaluated. Patients' demographic details, procedural information, and posttreatment outcomes were prospectively documented. RESULTS: A total of 23 MINI PCNLs were performed on 23 kidneys of 12 patients whose ages ranged from 1.6 to 14.6 years. The median stone burden was 3.44 cm(2), and there were 11 "Staghorn" stones. The procedure was primary via a single puncture in 19 kidneys and secondary using a preexisting nephrostomy tract in 4 kidneys. Access was successful in all primary and two secondary cases, for a total of success rate of 91.3 %. Stones were fragmented using a Holmium laser and/or lithoclast, and fragments were irrigated or sequentially removed by various stone grasping devices. The mean procedural X-ray screening time and total stone extraction period were 4.5 and 109.4 min, respectively. The primary stone free rate was 83.6 %, which increased to 90.5 % after treating the residual fragments. Postoperative hydrothorax developed in one patient, which required a chest drain. Symptoms of chest infection and positive urine culture were detected in one and two patients, respectively. CONCLUSIONS: Our initial experience supports previous reports that MINI PCNL is safe and effective for the management of renal stones in children.

Unenhanced CT for the evaluation of acute ureteric colic: the essential pictorial guide.

Acute ureteric colic is a common emergency, often dealt with by the emergency physician or general practitioner and referred on to the urologist. Unenhanced CT of the kidneys, ureters and bladder (CTKUB) is the 'gold standard' imaging investigation for establishing a diagnosis and guiding management. An appreciation of the CTKUB signs, which support or refute a diagnosis of ureteric colic, is highly valuable to the clinician when making a urological referral, and to the urologist, who must make appropriate management plans. All salient diagnostic and supportive features of ureteric colic are carefully illustrated, as are important radiological mimics, with the objectives of educating and informing the non-radiologist. Ready access to the picture archive and communication system (PACS) allows all specialists involved to interpret the radiological report with the benefit of images. A stone within the ureter may not always be readily apparent. Soft tissue rim sign around a calcific focus is an important indicator of a ureteric stone, whereas a comet tail sign suggests a phlebolith (a calcified venous thrombosis), a radiological mimic of a ureteric stone. Numerous secondary signs of ureteric obstruction may be present including hydronephrosis and perinephric stranding, and can help to confirm the diagnosis. The relative diagnostic weighting of signs is discussed, and a checklist is provided to assist with interpretation. Unexpected alternative radiological diagnoses are also illustrated, which may have significant management consequences necessitating specialist referral.

Forgotten indwelling stent in a transplanted kidney: a case report.

INTRODUCTION: Forgotten or retained ureteric stents are a well-recognised phenomenon with the potential to cause a range of complications, the most dangerous of which is obstructive nephropathy. These risks are potentially devastating when the patient has a single functioning transplanted kidney. Here we describe the case of a renal transplantation patient with a forgotten ureteric stent of 10 years, who presented with irritative bladder symptoms and was successfully managed using a multimodal urological approach with specialist advice on antibiotic prophylaxis. To the best of our knowledge this is the longest documented time period for a forgotten ureteric stent in a transplantation patient and is unusual in that obstructive nephropathy did not occur. * CASE PRESENTATION: A 32-year-old man with a history of end stage renal failure of unknown aetiology received a cadaveric renal transplant in 1995. An indwelling JJ stent was placed at the time of transplant to protect the vesicoureteric anastomosis. The patient made an unremarkable recovery and initially attended regular follow up in the renal transplant clinic. He was subsequently lost to transplant clinic follow up. In 2005 at the age of 42 he was referred to a nephrologist with irritative bladder symptoms. Renal tract imaging with ultrasound and a plain film demonstrated a retained encrusted ureteric stent. * CONCLUSION: The removal of a retained encrusted ureteric stent always provides a urological challenge. This case demonstrates that multimodal treatment involving a combination of endourological and percutaneous techniques can be employed with success even when the patient has a heavily encrusted stent for a single functioning transplanted kidney. Involvement of a microbiologist to advise on prophylactic antibiotics is deemed especially useful, as the immunosuppressed transplant patient is at particular risk of sepsis secondary to bacteraemia as a result of the endoscopic manipulation of the colonised encrusted stent. This case also provides further evidence to highlight the potential benefits of a stent registry.

Acute tubular necrosis following radiofrequency ablation of a renal cell carcinoma.

We described a case of acute tubular necrosis in a patient with a renal cell carcinoma in a solitary kidney following renal RFA.

A retrospective evaluation of Randall's plaque theory of nephrolithiasis with CT attenuation values.

PURPOSE: We examined the computed tomography attenuation values (HU) of renal papillae in stone formers (SF) to determine whether nephrolithiasis is associated with radiographic changes in renal papillae to investigate the Randall's plaque theory. MATERIALS AND METHODS: Two observers independently and retrospectively recorded the HU of the renal medullae and cortex in 90 patients with a unilateral single calculus within kidney or ureter, and in 104 cases in control group (CG) matched for age and renal functions. RESULTS: The patient ages were similar in the stone former and control groups. However, the male-female ratio was significantly greater in the SF group (68:22) than in the CG (42:62, P<0.0001). Left-right ratio in SF group was 50:40. The inter-rater agreement was kappa=0.53 (95% CI: 0.42, 0.64). Mean HU of all papillae of affected side in stone-formers (ASSF) was significantly greater than that in CG (39.6 versus 29.6, P<0.0001). When comparing affected and non-affected sides within the SF group, there was no significant difference (39.6 versus 38.4, P=0.16). The receiver operating characteristic (ROC) analysis showed area under curve=0.94 with optimal cut-off at 34 HU. At this point the specificity, sensitivity, PPV and NPV were 90%, 90%, 33% and 99%, respectively. CONCLUSION: HU of the renal papilla is significantly increased in SF in the affected and the non-affected kidneys when compared to the CG. This finding may form one of the risk indicators to determine the future follow up and clinical management for the potential SF.

Protecting the ureter during radiofrequency ablation of renal cell cancer: a pilot study of retrograde pyeloperfusion with cooled dextrose 5% in water.

PURPOSE: To describe early experience with cooled dextrose 5% in water (D5W) solution retrograde pyeloperfusion during radiofrequency (RF) ablation of renal cell carcinoma (RCC) within 1.5 cm of the ureter with respect to feasibility, safety, and incidence of residual/recurrent tumor in proximity to the cooled collecting system. MATERIALS AND METHODS: Between November 2004 and April 2007, 17 patients underwent 19 RF ablation sessions of RCCs within 1.5 cm of the ureter during cooled D5W pyeloperfusion (nine men, eight women; mean tumor size, 3.5 cm; mean age, 73 y; mean distance to ureter, 7 mm). RF ablation was performed with pulsed impedance control current. The records and imaging studies of patients treated with this technique were reviewed for demographics, indication, technique, complications, and tumor recurrence. RESULTS: All 19 RF ablation and ureteral catheter placement procedures were technically successful. No patient developed a ureteral stricture or hydronephrosis during a mean of 14 months of follow-up (range, 4-32 months). Three patients had residual tumor on the first follow-up imaging study, but all three tumors were completely ablated after a second RF ablation session. No complications or deaths occurred. No recurrent tumor was seen anywhere in the treated tumors, and there was complete ablation of the tumor margin in proximity to the collecting system. CONCLUSIONS: RF ablation of RCC within 1.5 cm of the ureter is feasible with cooled D5W retrograde pyeloperfusion and is not associated with reduced efficacy, ureteral injury, or early recurrence.

Infectious complications after percutaneous radiofrequency ablation of renal cell carcinoma in patients with ileal conduit.

Percutaneous renal radiofrequency (RF) ablation is a safe and minimally invasive treatment for renal cell carcinoma. The most common minor complications are pain, self-limiting hematuria, and postablation syndrome. Major complications are rare and include significant hemorrhage and thermal injury to the ureter. Reports of infectious complications after ablation are uncommon, but increased risks in patients with ileal conduits have been reported. The present report describes two patients with ileal conduits who underwent percutaneous renal RF ablation and developed infectious complications (a renal abscess and a calyceal-cutaneous fistula) despite prophylactic antibiotic treatment.

Initial experience with the resonance metallic stent for antegrade ureteric stenting.

BACKGROUND AND PURPOSE: We describe our initial experience with a new metallic ureteric stent which has been designed to provide long-term urinary drainage in patients with malignant ureteric strictures. The aim is to achieve longer primary patency rates than conventional polyurethane ureteric stents, where encrustation and compression by malignant masses limit primary patency. The Resonance metallic double-pigtail ureteric stent (Cook, Ireland) is constructed from coiled wire spirals of a corrosion-resistant alloy designed to minimize tissue in-growth and resist encrustation, and the manufacturer recommends interval stent change at 12 months. METHODS: Seventeen Resonance stents were inserted via an antegrade approach into 15 patients between December 2004 and March 2006. The causes of ureteric obstruction were malignancies of the bladder (n = 4), colon (n = 3), gynecologic (n = 5), and others (n = 3). RESULTS: One patient had the stent changed after 12 months, and 3 patients had their stents changed at 6 months. These stents were draining adequately with minimal encrustation. Four patients are still alive with functioning stents in situ for 2-10 months. Seven patients died with functioning stents in place (follow-up periods of 1 week to 8 months). Three stents failed from the outset due to bulky pelvic malignancy resulting in high intravesical pressure, as occurs with conventional plastic stents. CONCLUSION: Our initial experience with the Resonance metallic ureteric stent indicates that it may provide adequate long-term urinary drainage (up to 12 months) in patients with malignant ureteric obstruction but without significantly bulky pelvic disease. This obviates the need for regular stent changes and would offer significant benefit for these patients with limited life expectancy.

The detour extra-anatomic stent--a permanent solution for benign and malignant ureteric obstruction?

OBJECTIVES: We describe our experience of the Detour extra-anatomic stent (EAS) (Mentor-Porgés, UK) for permanent bypass of complete upper urinary tract obstruction. The self-retaining expanded polytetrafluoroethylene-silicone tube, placed in the kidney using a percutaneous route, is tunnelled under the skin and sutured into the bladder to establish extra-anatomical urinary drainage. METHODS: From April 2002 to November 2005, a total of nine Detour stents were inserted into eight patients; one patient needed bilateral stent insertions. The causes for ureteric obstruction were persistent malignant disease in three and complicated benign disease in five patients. RESULTS: To date, four of five patients with benign disease are alive; one died unexpectedly of metastatic malignancy. The only stent-related complications were infection and haematuria. The two patients with malignancy have subsequently died, but there were no urinary drainage problems for their second and third years of life, respectively. CONCLUSIONS: The preliminary data presented here suggest that the Detour EAS offers a permanent and minimally invasive method to establish internalisation of urinary drainage to bypass complete ureteric obstructions for which conventional stenting has failed, open surgery has been tried and failed or was not considered feasible, and long-term nephrostomy drainage was not favoured.

Radiofrequency ablation of a central renal tumor: protection of the collecting system with a retrograde cold dextrose pyeloperfusion technique.

Renal radiofrequency (RF) ablation therapy is a safe and effective therapy for small renal cell carcinoma. Although the risk of complications is low, the potential for ureteral or calyceal injury does increase in the case of a centrally located lesion. A retrograde cold dextrose pyeloperfusion technique was designed to protect the collecting system in a patient who underwent percutaneous RF ablation of a central tumor of the left kidney.

Image-guided percutaneous radiofrequency ablation and incidence of post-radiofrequency ablation syndrome: prospective survey.

PURPOSE: To evaluate prospectively the incidence of post-radiofrequency (RF) ablation syndrome and determine its impact on the quality of life in the 10 days after percutaneous RF ablation. MATERIALS AND METHODS: This study was approved by the institutional review board and was HIPAA compliant. Informed consent was obtained for this survey in all patients by the interventional nurse coordinators. Thirty-six patients (20 men, 16 women; mean age, 69.3 years; range, 40-88 years) underwent RF ablation for 26 liver tumors and 17 renal tumors. Twenty control patients (11 men, nine women; mean age, 60.8 years; range, 35-76 years) underwent biopsy of focal liver lesions or renal lesions. With a standardized questionnaire, a telephone survey was conducted on days 1, 3, 5, and 10 after RF ablation or biopsy. The symptoms and interference with lifestyle were documented prospectively with a numeric intensity scale by using grades 0-10. Statistical analysis with Fisher exact test and analysis of variance was performed. RESULTS: After RF ablation, 15 (42%) patients developed low-grade fever (P < .001), 29 (81%) had flulike symptoms (P < .001), and four were asymptomatic. Symptoms peaked on day 3 and mainly resolved by day 10. Twelve (33%) patients had complete post-RF ablation syndrome: fever and flulike symptoms (P = .005). Flulike symptoms were more prolonged when they were accompanied with fever, peaked on day 5, and resolved more quickly for patients with renal lesions than they did for patients with liver lesions. Four patients had persistent fever caused by pneumonia (n = 2), pleural effusion and atelectasis (n = 1), or liver abscess (n = 1). No control patients developed both fever and flulike symptoms. Post-RF ablation patients with symptoms experienced significantly greater pain and interference with general and work activities, which peaked on day 1, than did control patients (P = .01 [pain], P < .001 [general and work activities]). CONCLUSION: Complete post-RF ablation syndrome occurs in approximately one-third of patients but is self-limiting within 10 days after the procedure. Persistent or late-onset fever may indicate concurrent infection elsewhere or possible abscess formation. SUPPLEMENTAL MATERIAL: radiology.rsnajnls.org/cgi/content/full/237/3/1097/DC1