Perinephric Hematoma Research Articles

Minimally Invasive Percutaneous Treatment of Small Renal Tumors with Irreversible Electroporation: A Single-Center Experience

PurposeTo evaluate whether irreversible electroporation (IRE) can be used as an ablation technique for small renal tumors (T1a cancers or small benign tumors) and to describe features after ablation on computed tomography (CT) or magnetic resonance (MR) imaging. Materials and MethodsIn this retrospective study, 20 patients (mean age, 65 y ± 12.8 y) underwent CT-guided IRE of T1a renal carcinoma (n = 13) or small benign or indeterminate renal masses < 4 cm in size (n = 7). Mean tumor size was 2.2 cm ± 0.7. The ablation area was verified with contrast-enhanced imaging performed immediately after the procedure to determine technical success. Imaging was performed 6 weeks (20 of 20 patients), 6 months (15 of 20), and 12 months (6 of 20) after ablation. Medical records and CT/MR imaging features of all patients were reviewed for recurrence, symptoms, and complications after treatment. ResultsTechnical success was achieved in all patients (100%); there were no major procedure-related complications. Minor complications occurred in 7 patients, including self-limiting perinephric hematomas, pain difficult to control, and urinary retention. Mean procedure time was 2.0 hours ± 0.7. At 6 weeks, 2 patients required salvage therapy because of incomplete ablation. At 6 months, all 15 patients with imaging studies available had no evidence of recurrence. At 1 year, 1 patient (1 of 6) was noted to have experienced recurrence. CT/MR imaging after IRE ablation demonstrated an area of nonenhancement in the treatment zone that involuted over ~6 months. ConclusionsRenal IRE appears to be a safe treatment for small renal tumors. Tumors treated with IRE demonstrated nonenhancement in the treatment zone with involution on follow-up CT/MR imaging.

Pediatric calyceal diverticulum treatment: An experience with endoscopic and laparoscopic approaches

The symptomatic calyceal diverticulum is a rare event in the pediatric population. In adults, surgical options include ureteroscopy, percutaneous ablation, and laparoscopic decortication but there is a lack of experience in the literature with these techniques. We present our experience with both the ureteroscopic and laparoscopic approach to treating the pediatric calyceal diverticulum. We performed a retrospective case series looking at patients who underwent treatment for calyceal diverticulum at our institution from January 2009 to May 2014. We reviewed patient demographics, indications for intervention, radiographic appearance, type of intervention, and perioperative outcomes. Ureteroscopic approach included dilation of infundibulum and ablation of diverticular cavity. Laparoscopic approach included ablation of the diverticulum with argon diathermy with or without surgical closure of the ostium. There were 13 patients who underwent 15 procedures for symptomatic calyceal diverticulum (Table). Median age was 11 years. Indications for intervention were: pain and increasing size of diverticulum (8/15, 55%), hematuria (3/15, 20%), UTI (3/15, 20%), and calculi (1/15, 5%). 11/15 (73%) procedures were managed endoscopically and 4/15 (27%) were managed with laparoscopic decortication. Ureteral stent was left in all patients for a mean duration of 51 days (15-120 days). Follow up imaging at median of 2.1 years (0.5-4 years) revealed an initial success rate of 85% (11/13 patients). Two patients failed initial intervention (persistent pain/increasing size) necessitating successful secondary minimally invasive procedures. There were 2 (13%) complications: a perinephric hematoma post endoscopic ablation which resolved spontaneously and a deep venous thrombosis in a patient with a coagulation disorder in the laparoscopic group. Limitations of our study include its retrospective design, lack of standardization of the treatment approach amongst the four treating surgeons, and the small number of patients requiring intervention for this relatively rare diagnosis. Our study is the largest to date in the pediatric population and is the first to report outcomes with ureteroscopic management of the calyceal diverticulum. We found that the pediatric calyceal diverticulum can be successfully treated in a minimally invasive manner. The endoscopic approach should be the first line option for patients with small, endophytic diverticula, particularly those located in the upper and mid pole. The laparoscopic approach is more invasive but should be considered for large diverticula that are exophytic with thin overlying parenchyma.

Endoscopic Ultrasonography-Guided Fine Needle Aspiration of Kidney Masses

Scan the quick response (QR) code to the left with your mobile device to watch this article's video abstract and others. Don't have a QR code reader? Get one by searching 'QR Scanner' in your mobile device's app store. clinical management strategy is based on imaging features. A solid, contrast-enhancing renal mass seen on CT or MRI is considered malignant until proven otherwise, and operative resection is undertaken in appropriate candi- dates. A histologic diagnosis remains necessary in selected patients, such as those with radiographically indetermi- nate lesions, in those considering partial nephrectomy, and to confirm malignancy in patients unfi tf or surgery. Tissue diagnosis is critical to discern appropriate treat- ment in this subgroup. Renal biopsies are usually per- formed percutaneously under transabdominal ultrasound (US) or CT guidance. Percutaneous fine needle aspiration (FNA) can discriminate benign from malignant neoplasms in 91% of cases with histologic classification of tumor type possible in 87% of tumors. 2 Nondiagnostic/inade- quate specimens are largely owing to sampling error and occur in about 30% of cases. Data from case reports and series suggest endoscopic ultrasound (EUS)-guided FNA may provide an additional diagnostic technique for tissue acquisition of renal mass lesions.

1:45 PM, Abstract No. 271 - Complication and readmission rates following same day discharge after percutaneous renal tumor ablation

There is variability in the post-percutaneous renal tumor ablation management with overnight admission being routine practice in many institutions. The aim of this study is to assess the clinical outcomes and readmission rates following same day discharge post CT-guided cryoablation and RFA of renal tumors. 173 consecutive renal tumor ablations for which same day discharge was planned, performed between 1/2004 and 1/2014, were retrospectively reviewed. The primary outcome was the rate of readmission within 30 days of same-day discharge. The secondary outcomes included the rate and clinical outcomes of periprocedural complications requiring admission. Perinephric hematoma, the most common complication, was evaluated by manual volume quantification from intraprocedural and follow-up cross sectional imaging and compared between admitted and discharged patients. 165 patients (95.4%) were discharged same-day with short-term readmission in 1 case (0.6%) for acute on chronic kidney injury. 8 patients (4.6%) who were planned to be discharged the same day, were admitted for complications related to ablation (Table 1). The majority of these complications were perinephric hematomas, with a mean volume of 272 mL (SE: 163) in those who were admitted versus 42 mL (SE: 15) in those who were discharged same day (P = 0.04). All instances were detected during the standard 4 hour observation period and all were managed conservatively without requiring surgery or renal artery embolization. No short-term readmissions occurred following discharge of admitted patients. Routine same day discharge following percutaneous renal tumor thermoablation can be performed with a low rate of short-term readmission and low rate of periprocedural complications. The majority of periprocedural complications can be managed conservatively and discharged same day.

Primary Pulmonary Choriocarcinoma

We present a case of a 25-year-old Hispanic woman who presented to emergency department with chief complaint of left lower quadrant abdominal pain. Initial workup revealed positive pregnancy test. Serum human chorionic gonadotropin was 36,478 (normal range, 0 to 8.0) IU/mL. She underwent diagnostic laparoscopy with dilatation and curettage, which did not reveal any evidence of intrauterine or extrauterine pregnancy. Chest and abdomen radiographic findings were significant for a heterogenously enhancing 2.2×1.7×1.6 cm nodule in superior segment of the right lower lobe of the lung and a large perinephric hematoma. We performed radial endobronchial ultrasound-guided transbronchial biopsies of the right lower lobe lesion. Pathologic specimen revealed choriocarcinoma.

Perinephric hematoma following renal biopsy: A case report and literature review

The risks associated with performing a percutaneous renal biopsy have substantially decreased in the past two decades because of technical advances in the method. However, bleeding complications still occur, resulting in increased hospital stay, treatment costs and even mortality. The purpose of this case report is to discuss the life threatening complications like perinephric hematoma following a renal biopsy in a high risk patient with severe renal failure. The clinical, radiological findings, prognosis of a massive perinephric hematoma following a renal biopsy in a high risk patient with severe renal failure are discussed. We report a case of 39-year-old male, non-diabetic, hypertensive since 5 years who presented with unexplained severe renal failure. After dialyzing adequately, he was subjected to right renal biopsy using real time ultrasound guided automated renal biopsy gun. Post-biopsy was uneventful, until 72 h when he developed massive right perinephric hematoma following a heparin-free hemodialysis. He continued to be hypotensive despite hemostatics, blood products, plasma expander transfusion. Unfortunately, he expired before definitive management like renal angiogram and intervention was attempted. To the best of our knowledge, this is one of few reports of the occurrence of life-threatening complication like perinephric hematoma in a patient with severe renal failure on heparin free hemodialysis following a renal biopsy after 72 h.

Adequacy and Complication Rates with 14‐ vs. 16‐gauge Automated Needles in Percutaneous Renal Biopsy of Native Kidneys

In performing percutaneous renal biopsy (PRB) of native kidneys, an increasing use of 16-gauge automated biopsy needles has been observed. We compare the adequacy and safety of PRBs in adults performed with a 14-gauge (n = 82) vs. 16-gauge (n = 55) automated needle using real-time ultrasound (US) from 1/2010 to 12/2013. Baseline clinical and laboratory data along with outcome data (renal US 1-hour postbiopsy, biopsy adequacy, and safety) were collected prospectively. There was no difference in age, gender, blood pressure, serum creatinine, or pre-PRB hemoglobin at baseline for PRBs performed with a 14- vs. 16-gauge needle. The number of glomeruli obtained per biopsy was similar (29 ± 11 vs. 31 ± 14, p = 0.6) and adequate tissue for diagnosis was obtained in 99% and 100% of biopsies. The clinical complication (8.5% vs. 9.1%, p = 1.0), transfusion (7.3% vs. 7.2%, p = 1.0), and embolization (3.7% vs. 1.8%, p = 0.6) rates were not significantly different for 14- vs. 16-gauge needles, but by routine renal US 1-hour post-PRB, a perinephric hematoma was demonstrated more often in biopsies done with the 14-gauge needle (39% vs. 22%, P 0.04). Thus, while the success of PRB of native kidneys is similar for both needle gauges, the potential for complication may be less using a 16-gauge automated needle.

Symptomatic subcapsular and perinephric hematoma following ureteroscopic lithotripsy for renal calculi.

Ureteroscopic lithotripsy (URSL) is believed to be associated with less risk of symptomatic renal hematoma than extracorporeal shockwave lithotripsy (SWL) and percutaneous nephrolithotomy (PCNL). We sought to document the rate of and risk factors for this rare complication following URSL for renal calculi. With Institutional Review Board approval, we reviewed 1087 cases of URSL performed between July 2009 and October 2012 for four surgeons. We identified cases for renal calculi complicated by symptomatic "hematoma" by searching electronic medical records of patients undergoing URSL with a web-based search tool and cross-referencing with a departmental quality improvement database for postoperative complications. Chi-squared tests were used to assess risk factors. Among 877 renal units exposed to URSL for renal calculi, 4 were complicated by symptomatic subcapsular hematomas (SH) and 3 by symptomatic perinephric hematomas (PH), yielding a 0.5% and 0.3% rate for each complication, respectively. Pain was the primary presenting symptom. Almost all cases presented within 24 to 48 hours postop. Two PH patients required postoperative blood transfusion. Four patients (two SH, two PH) were hospitalized for observation. Ureteral sheaths were used in two cases (one PH and one SH). There was no association with age, diabetes, body mass index (BMI), or operative duration (p-values all>0.05). However, hematoma did correlate with female gender, preoperative hypertension, preoperative ureteral stenting, intraoperative ureteral sheath use, and postoperative ureteral stenting (all p-values<0.0001). While symptomatic hematoma is a complication of URSL, the rate of such outcome (0.8%) is far less than that reported by prior series with SWL and PCNL. This may partially be attributable to collection biases, where subclinical cases are not imaged, or anchoring biases, where clinicians attribute symptoms to another possible etiology. This outcome can be morbid, but can often be conservatively managed with observation.

Kidney Biopsy: An Experience from Tertiary Hospital

Kidney Biopsy is an important diagnostic tool in Nephrology. It is useful in Nephrology in terms of diagnosis, prognosis and management. There is little information on renal biopsy data from central Nepal. We describe our center`s experience in kidney biopsy in term of histological patterns, complications and outcomes. We prospectively analyzed the biopsies data of patients over a period of one and half year. All kinds of kidney disease patients were included for kidney biopsy, irrespective of their clinical syndromes and underlying diagnosis. A total of 75 biopsies were analyzed. Majority of them were females; 42 (56%). Most of the biopsies; 63 (84%) were from younger subjects ≤ 45 years and majority of them fell in the age group 11-20 years. Most common clinical renal syndrome to undergo biopsy was Sub Nephrotic range Proteinuria in 40 (53.3%). Among comorbid conditions, 40 (53.3%) had Hypertension. The most common histological pattern seen was Mesangial proliferative Glomerulonephritis seen in 18 (24%). Among complications associated with the procedure, macroscopic hematuria was seen in 5 (6.7%) cases and clinically significant perinephric hematoma causing pain was seen in 4 (5.3%). There was no mortality associated with biopsy procedure. Sub Nephrotic range Proteinuria was the commonest clinical renal Syndrome observed. In terms of renal histology, Mesangial Proliferative Glomerulonephritis (MesPGN) was the commonest histological pattern observed. Kidney biopsy is a safe procedure without any significant adverse events.

MP20-16 INTERIM RESULTS OF A RANDOMIZED TRIAL COMPARING NARROW VERSUS WIDE FOCAL ZONES FOR SHOCK WAVE LITHOTRIPSY OF RENAL CALCULI

You have accessJournal of UrologyStone Disease: Basic Research I1 Apr 2014MP20-16 INTERIM RESULTS OF A RANDOMIZED TRIAL COMPARING NARROW VERSUS WIDE FOCAL ZONES FOR SHOCK WAVE LITHOTRIPSY OF RENAL CALCULI R. J. D'.A. Honey, Tarek Alzahrani, Daniela Ghiculete, and Kenneth T. Pace R. J. D'.A. HoneyR. J. D'.A. Honey More articles by this author , Tarek AlzahraniTarek Alzahrani More articles by this author , Daniela GhiculeteDaniela Ghiculete More articles by this author , and Kenneth T. PaceKenneth T. Pace More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2014.02.738AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES The Modulith SLK-F2 electromagnatic lithotripter (Storz Medical) is the first lithotripter on the market with a unique design that allows for a dual focus system with the option of either a narrow (6x28 mm) or wide (9x50 mm) focal zone. Ex vivo data shows that disintegration capacity and renal vascular injury are independent of the focal diameter of the SW generator at the same peak pressure and disintegration power. The objective of this study is to compare the single-treatment success rates of narrow and wide focal zones for the shock wave lithotripsy (SWL) of renal stones. METHODS 118 patients with a previously untreated radio-opaque solitary stone located within the renal collecting system, measuring 5 to 15 mm in greatest diameter, were randomized to receive narrow or wide focus lithotripsy. Patients were followed with KUB x-rays and renal ultrasound at 2 and 12 weeks post lithotripsy to assess stone free status. Urinary markers indicating the degree of renal cellular damage (microalbumin and Beta-2 macroglobulin) were measured pre- and post-SWL, 24 hours post-SWL and 7 days post-treatment. Primary outcome was single-treatment success rate, defined as stone-free or adequate fragmentation (sand and asymptomatic fragments <=4mm) at 3 months post-treatment. RESULTS 61 (51.7%) patients were randomized to narrow focus lithotripsy versus 57 (48.3%) patients wide focus. The groups were similar in baseline characteristics including (age, gender, BMI, stone size and density and skin to stone distance). The overall success rates were not significantly different at 2 weeks post treatment (Narrow: 72.1% vs Wide: 61.4%; P = 0.216) nor at 3 months (Narrow: 68.3% vs Wide: 58.9%; P = 0.292). The overall complication rates was also comparable in the two groups (Narrow: 24.6% vs Wide: 17.5%; P = 0.349) including similar rates of perinephric hematoma (Narrow: 3.3% vs Wide: 3.5%; P = 0.945). The microalbumin-to-creatinine ratio was significantly different between the two groups (p=0.019), but that difference was gone within 24 hours after the treatment. CONCLUSIONS Interim results indicated that single-treatment success rate and complications are comparable when using the narrow or wide focus of the Modulith SLX-F2. There was a difference in renal injury as measured bymicroalbumin to creatinine ratio (with lower values in the narrow focal zone group), but these differences disappeared within 24h of treatment. We are continuing to recruit patients to a pre-planned sample size of 300. © 2014FiguresReferencesRelatedDetails Volume 191Issue 4SApril 2014Page: e202 Advertisement Copyright & Permissions© 2014MetricsAuthor Information R. J. D'.A. Honey More articles by this author Tarek Alzahrani More articles by this author Daniela Ghiculete More articles by this author Kenneth T. Pace More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Unsuspected serious abdominal trauma after falls among community-dwelling older adults

In elderly community-dwelling patients who experience ground-level falls, fractures or brain injury are the major concern. Serious abdominal injury is seldom contemplated. Identify all such patients presenting after a simple fall and admitted with serious blunt abdominal trauma to a single academic medical centre. Retrospective chart analysis. All patients with both diagnoses aged 65 years or more admitted over 1 year to the department of medicine, geriatrics, surgery or urology were identified. Out of 546 patients screened, three cases of ground-level falls leading to splenic rupture, isolated gallbladder rupture with gallstone ileus and perinephric hematoma were found (0.55%) and are reported. Falls in elderly patients are exceedingly common mandating recognition of even rare complications. Physicians should be more aware of the possibility of occult and serious consequences of blunt abdominal trauma after falls among older adults, albeit rare.

Renal Cell Carcinoma Metastasis from Biopsy Associated Hematoma Disruption during Robotic Partial Nephrectomy.

We describe a case in which a patient with a past medical history of ovarian cancer received a diagnostic renal biopsy for an incidentally discovered renal mass. During left robotic partial nephrectomy (RPN), a perinephric hematoma was encountered. The hematoma was not present on preoperative imaging and was likely a result of the renal biopsy. The renal cell carcinoma (RCC) and the associated hematoma were widely excised with negative surgical margins. On follow-up imaging at five months postoperatively, a recurrent renal mass at the surgical resection bed and several new nodules in the omentum were detected. During completion left robotic total nephrectomy and omental excision, intraoperative frozen sections confirmed metastatic RCC. We believe that a hematoma seeded with RCC formed as a result of the renal biopsy, and subsequent disruption of the hematoma during RPN caused contamination of RCC into the surrounding structures.

E1 Perinephric hematoma as a complication of SWL for kidney stones; incidence, possible causes, signs and symptoms

E1 Perinephric hematoma as a complication of SWL for kidney stones; incidence, possible causes, signs and symptoms

SAFETY AND SAMPLE ADEQUACY OF RENAL TRANSPLANT SURVEILLANCE BIOPSIES

Purpose: To report on the safety and adequacy of surveillance biopsy for detecting subclinical lesions in clinically stable renal grafts.Materials and methods: We established an in-patient surveillance biopsy program with the elective performance of a renal transplant biopsy during the first year after renal transplantation. All biopsies in our centre were performed or supervised by the same operator. Patients were admitted to the hospital the day of biopsy and were discharged after 24h of observation. All patients were biopsied in supine position, using a 16-gauge needle with a spring-loaded gun (Bard®) under real-time ultrasound guidance. Complication rates were retrospectively scored using the patients’ charts and blood counts before and after biopsy. Major complications were defined as those requiring an intervention for resolution, a transfusion of blood products or an invasive procedure (angiography or surgery), and those that led to acute renal obstruction or failure, septicaemia, graft loss or death. In all other cases complications were considered minor. An adequate biopsy was defined as the presence of 7 or more glomeruli and at least one artery in the biopsy specimen.Results: We performed 282 surveillance biopsies in 248 patients between January 2006 and December 2011. None of the complications were major. We observed 6% minor complications (n = 17). 5.6% (n = 16) of the complications were related to bleeding, with macroscopic haematuria as the most common condition (n = 10; 3.5%), followed by pain (n = 6; 2.1%) eighter due to a perinephric hematoma (n = 5) or a subcutaneous hematoma (n = 1). The biopsies contained a median number of 9 glomeruli (range 0-39) with 70% of biopsies containing at least 7 glomeruli and one artery.Conclusion: The procedure for taking surveillance biopsies was proven to be safe. There were no major complications and only rare minor complications. The majority of the samples were adequate for histological examination.

Computed Tomography Angiography in the Diagnosis of ANCA-Associated Small- and Medium-Vessel Vasculitis

Polyarteritis nodosa (PAN) is a systemic necrotizing vasculitis that typically occurs without detectable antineutrophil cytoplasmic antibody. It leads to aneurysm formation by affecting muscular arteries, usually those of medium size but also occasionally those of small size. Kidney involvement is common, leading to reduced glomerular filtration rate, hypertension, rupture of renal arterial aneurysms causing perinephric hematomas, and renal infarctions in those with severe vasculitis. Similar to PAN, microscopic polyangiitis (MPA) leads to aneurysm formation; however, MPA usually is associated with antineutrophil cytoplasmic antibody, and glomerulonephritis is a more common feature of MPA. Although kidney biopsy may show classic vascular changes in both PAN and MPA, this procedure is not without risk of significant bleeding due to aneurysm rupture. We present 2 cases of renal aneurysms that were diagnosed as MPA using computed tomography angiography (CTA), allowing implementation of appropriate immunosuppressive therapy. Follow-up CTA after treatment showed resolution of all previously observed abnormalities. CTA is a useful alternative to kidney biopsy in establishing both the extent of disease in renal aneurysms and allowing for tracking of disease progression and response to therapy.

Midterm safety and efficacy of percutaneous renal cryoablation

Purpose Many series evaluating oncologic efficacy of renal mass cryoablation are limited due to follow-up time of less than 12 months. Given the relatively slow growth kinetics of renal cell carcinoma (RCC), clinical success may be overestimated at this early timepoint. We reviewed outcomes on patients with no less than 12 months follow-up. Materials and Methods We reviewed patients seen at our multi-disciplinary Small Renal Mass Center treated with percutaneous cryoablation from February 2008-July 2011. Patients were followed by Urology and Interventional Radiology with CT and/or MRI q4 months for year 1, q6 months for year 2, and annually thereafter. Tumors were evaluated by size and location (exophytic, mixed, or central). Absence of previously identified contrast enhancement was used to define clinical success. Results Under CT guidance, 49 masses in 47 patients were treated in 49 sessions using 2-5 cryoprobes (Healthtronics, Austin, TX). One patient with 2 tumors had simultaneous ablation while another developed a second tumor 15 months after successful cryoablation. Mean tumor diameter was 2.7 +/- 0.8 cm (range: 1.1 - 4.9 cm). Twenty six masses (53%) were exophytic, 20 (41%) were mixed and 3 (6%) were central. Clinical success was achieved in 48/49 tumors (98%). One patient developed local progression 13 months after ablation, and underwent successful salvage cryoablation with no residual disease at 19 additional months (32 months total). Mean follow-up time was 27 +/- 10 months (median 27 months; range 12-49 months). 30 patients (64%) had greater than 2 years follow-up. 19 (40%) and 11 (24%) had 24-36 months and > 36 months follow-up, respectively. Metastasis and disease-free survival were 100%. One patient died of a second malignancy for an overall survival of 98%. Three minor complications occurred (6%). All were perinephric hematomas that did not require additional management. Conclusion Percutaneous renal cryoablation demonstrates durable oncologic outcomes at a median of 27 months follow-up and represents an effective, minimally-invasive treatment option for small renal masses. The solitary local progression was salvaged with repeat treatment. Complications were rare and managed conservatively.

1:30 PM Abstract No. 206 - Surveillance protocol transplant renal biopsy: assessment of safety in 549 cases at a tertiary care transplantation center

Purpose Renal transplant surveillance biopsy performed at fixed time points after kidney transplantation is aimed at detecting subclinical graft rejection prior to overt manifestation as serum creatinine elevation. While these scheduled biopsies may provide a histologic basis for adjusting immunosuppressive regimens, they subject patients to intrinsic risk associated with invasive tissue sampling. This study was undertaken to assess the safety of a surveillance protocol transplant renal biopsy program at an urban tertiary care transplantation center. Materials and Methods In this single institution retrospective study, 399 patients underwent extraperitoneal renal transplant surveillance biopsy between January 2010 and October 2012. In general, biopsies were performed 1, 3, 6, and 12 months post-transplant, and annually thereafter. 18-gauge samples were obtained using direct sonographic guidance, with 3-4 needle passes made in each case with on-site pathologic assessment of tissue adequacy. Medical record review was used to identify procedure-related complications, which were graded according to the Society of Interventional Radiology classification of complications. Results 549 renal transplant surveillance biopsies were performed during the study period. Procedure-related complications occurred in 7/549 (1.3%) cases, and included 1 minor complication and 6 major complications. The minor complication consisted of transient post-biopsy hematuria. Major complications included 4 peri-nephric hematomas (1 requiring percutaneous drainage, 1 requiring operative evacuation, and 1 resulting in compressive renal failure), 1 case of hematuria requiring prolonged hospitalization, and 1 arteriovenous fistula requiring embolization. There were no patient deaths. Conclusion Surveillance renal transplant biopsy may be performed with a high degree of safety. Future studies should aim to weigh the low but non-zero overall complication rate against the frequency of detected subclinical graft rejection requiring immunosuppressive medication modification.

Abstract No. 347 - Safety of same day discharge after renal tumor thermal ablation

Purpose Overnight hospital admission of patients after percutaneous renal ablation remains standard practice for many institutions. The aim of this study is to evaluate the safety of same day discharge of patients who undergo percutaneous CT-guided radiofrequency ablation (RFA) and cryoablation of renal tumors. Materials and Methods An IRB approved retrospective analysis was conducted of patients with renal tumors treated with percutaneous CT-guided RFA and cryoablation between January 2004 and June 2012. Ablation method, tumor size, complications and rates of hospital admissions were analyzed. Results A total of 153 procedures were performed on 134 patients including 82 cryoablations and 71 radiofrequency ablations. All patients were planned to be discharged the same day as their procedure following a standard 4 hour observation period. Overall, five of 153 encounters (3.3%) resulted in patients being admitted overnight. All five admissions occurred because of a complication detected during the first 4 hours after the procedure. Hospital admission was required in 4/71 (5.6%) RFA encounters and in 1/82 (1.2%) cryoablation encounters (p=0.28). Admission was required because of pneumothorax (n=2, one each group) and bleeding (n=3, all in the RFA group). There were no procedure related readmissions after same day discharge however 2/71 (2.8%) RFA encounters had perinephric hematomas detected after discharge but the patients did not require admission. There was no significant difference in the mean tumor size between the RFA (3.1cm) and cryoablation (3.3cm) groups (p=0.4). Conclusion Planned same day discharge after renal cryoablation and RFA is safe with no significant difference detected between the two procedures. Complications requiring admission are low and were detected in the immediate post-procedure observation period.

Review of the efficacy and safety of cryoablation for the treatment of small renal masses

Purpose: Small renal masses are increasingly being discovered incidentally on imaging for another reason. The standard of care of these masses involves excision by open or laparoscopic techniques. Recently, ablative techniques, such as radiofrequency ablation (RFA) and cryoablation, have taken a more prominent role in the treatment algorithm of these masses. We evaluate the effectiveness and safety of cryoablation to treat renal tumours.Methods: A review of the literature was conducted. There was no language restriction. Studies were obtained from the following sources: the Cochrane Library, PUBMED, EMBASE and LILACS.Results: There was no clinical trial identified in the literature. Thus, we described the results from 23 case series and retrospective studies with a reasonable sample size (number of reported patients in each study ≥30), with a total of 2104 analyzed tumours from 2038 patients. There was wide variability in the outcomes reported, but success rates were generally good. Follow-up was generally short, but some series reported outcomes at 5 years. The most common complications reported were hemorrhage (some of the patients requiring transfusion), perinephric hematoma and urine leaks.Conclusion: Cryoablation presents a feasible treatment for patients with small renal masses. Only short-term data are available and, assuch, meaningful conclusions regarding long-term cancer control cannot be made. More rigorous studies are needed.

Review of the efficacy and safety of cryoablation for the treatment of small renal masses.

Small renal masses are increasingly being discovered incidentally on imaging for another reason. The standard of care of these masses involves excision by open or laparoscopic techniques. Recently, ablative techniques, such as radiofrequency ablation (RFA) and cryoablation, have taken a more prominent role in the treatment algorithm of these masses. We evaluate the effectiveness and safety of cryoablation to treat renal tumours. A review of the literature was conducted. There was no language restriction. Studies were obtained from the following sources: the Cochrane Library, PUBMED, EMBASE and LILACS. There was no clinical trial identified in the literature. Thus, we described the results from 23 case series and retrospective studies with a reasonable sample size (number of reported patients in each study ≥30), with a total of 2104 analyzed tumours from 2038 patients. There was wide variability in the outcomes reported, but success rates were generally good. Follow-up was generally short, but some series reported outcomes at 5 years. The most common complications reported were hemorrhage (some of the patients requiring transfusion), perinephric hematoma and urine leaks. Cryoablation presents a feasible treatment for patients with small renal masses. Only short-term data are available and, as such, meaningful conclusions regarding long-term cancer control cannot be made. More rigorous studies are needed.