The "Mini-Perc" Technique of Percutaneous Nephrolithotomy with a 14-Fr Peel-away Sheath: 3-year Results in 72 Patients

OBJECTIVE: To assess the efficacy and safety of a "mini-perc" technique of percutaneous nephrolithotomy using a 14-Fr peel-away sheath for the removal of pyelocaliceal stones, and to determine appropriate inclusion criteria. MATERIALS AND METHODS: From July 1999 to June 2002, the medical records and radiographic images of 72 patients who underwent the "mini-perc" technique of percutaneous nephrolithotomy with a 14-Fr peel-away sheath, were reviewed to determine clinical history, stone characteristics, immediate stone free rate, final stone free rate after additional procedures, complications, and hospital stay. We also analyzed the effect of the longest stone diameter, the cumulative longest diameter of stones, the cumulative stone burden, and the stone density on the immediate stone free rate using a Fisher exact test. RESULTS: The only major complication, arterial bleeding, occurred in a patient with Child A liver cirrhosis and was successfully treated by embolization with coils and a gelatin sponge. The immediate stone free rate was 80.6 %, which was significantly influenced by stone diameter but not stone density. The mean hospital stay after the procedure was 3.97 days. CONCLUSION: The "mini-perc" technique of percutaneous nephrolithotomy, which uses the 14-Fr peel-away sheath, is a safe and effective modality for treating renal calculi.

Percutaneous Catheter Drainage of Complicated Traumatic Perirenal Hematoma: Case Report

A perirenal hematoma very commonly occurs after trauma. Treatment differs according to the degree of renal injury, though many cases are managed conservatively and complications are rare. We report two cases in which successful treatment of a perirenal hematoma involved percutaneous catheter drainage; in one there was bowel obstruction, and in the other the hematoma was infected.

Ultrasound-Guided Radiofrequency Thermal Ablation of Normal Kidney in a Rabbit Model: Correlation with CT and Histopathology

PURPOSE: To assess the feasibility and safety of using a cooled-tip electrode to perform percutaneous radiofrequency ablation of kidney tissue in rabbits, and to evaluate the ability of CT to reveal the appearance and extent of tissue necrosis during follow-up after ablation. MATERIALS AND METHODS: Using ultrasound guidance, a 17-G, cooled-tip electrode was inserted into the right lower portion of the kidney in 26 New Zealand White rabbits. Radiofrequency was applied for 2 mins, and biphasic helical CT scanning was used to assess tissue destruction and the presence or absence of complications immediately after the procedure and at 24 hrs, 2 and 3 days, and 1, 2, 3, 4, 5, 6 and 7 weeks. The study had three phases: acute [immediately killed : N=10]; subacute [killed at 24 hrs (n=3), 2 days (n=3), 3 days (n=1) : N=7]; chronic [killed at 1 week (n=4), 2 weeks (n=2), 4 weeks (n=1), 7 weeks (n=1) : N=8]. After the animals were killed, their kidneys were histopathologically examined and the radiologic and pathologic findings of lesion size and configuration were correlated. RESULTS: In each instance, ultrasound-guided radiofrequency ablations of the lower pole of the kidney were technically successful. Contrast-enhanced biphasic helical CT revealed regions of hypoattenuation devoid of parenchymal enhancement, and these correlated closely with true pathologic lesion size (r=0.884; p>0.05). In subacute and chronic models, CT scanning revealed gradual spontaneous resorption of the ablated lesion and the presence of perilesional calcification. Histopathologically, in the acute phase the ablated lesions showed coagulative necrosis and infiltration of inflammatory cells, and in the chronic phase there was clear cut necrosis of glomeruli, tubules and renal interstitium, with diminishing inflammatory response and peripheral fibrotic tissue formation. CONCLUSION: Ultrasound-guided renal radiofrequency ablation is technically feasible and safe. In addition, the avascular lesion measured at contrast-enhanced helical CT closely correlated with the size of ablated tissue. Contrast-enhanced CT may therefore be used for serially monitoring the effect of radiofrequency ablation. In the future, RF ablation may offer an alternative treatment option for renal cancer.

Percutaneous Retrieval of Upper Urinary Tract Foreign Bodies and Calculi

PURPOSE: To determine, when extracorporeal shockwave lithotripsy is contraindicated, the usefulness and safety of percutaneous management in the removal from the upper urinary tract of foreign bodies and calculi, or small remnants of these, retained affer percutaneous nephrolithotomy. MATERIALS AND METHODS: Between January 1996 and May 2001, we attempted to retrieve foreign bodies or calculi from the upper urinary tract of 20 patients, using various percutaneous techniques. There were eleven foreign bodies, namely fragmented nephrostomy catheters (n=2), migrated ureteric stents inaccessible to retrograde ureteroscopic management (n=8), and one metallic radiopaque marker which was separated from the pusher of the internal ureteral stent. Nine urinary tract calculi were present. These ranged in radiographically measured size from 4 to 8 mm in their largest diameter, and were found in the renal pelvis or calyx (n=5) and ureter (n=4). After percutaneous nephrostomy, all procedures involved the use of a 7-F to 14-F sheath, inserted under fluoroscopic guidance. Devices used for the retrieval of these objects include a stone basket retriever, loop snare, grasping forceps, and balloon catheter. RESULTS: In all cases except one, it was possible to retrieve calculi or other items from the upper urinary tract. No surgical procedure was required and no significant complications were encountered in any of the cases during or after the procedures. CONCLUSION: The percutaneous technique can be useful and safe in the management of foreign bodies or calculi present in the upper urinary tract.

Renal Artery Embolization Using a New Liquid Embolic Material Obtained by Partial Hydrolysis of Polyvinyl Acetate (Embol):Initial Experience in Six Patients

OBJECTIVE: To evaluate the therapeutic efficacy of a new liquid embolic materi-al,Embol, in embolization of the renal artery. MATERIALS AND METHODS: Embol is a new embolic material obtained by partial hydrolysis of polyvinyl acetate mixed in absolute ethanol and Iopromide 370 and manufactured by Schering Korea, Kyonggido, Korea. Six patients who underwent embolization of the renal artery using Embol were evaluated. Four were male and two were female and their ages ranged from 11 to 70 (mean, 53) years. Clinical and radiologic diagnoses referred for renal artery embolization were renal cell carcinoma (n = 3), renal angiomyolipoma (n = 2) and pseudoaneurysm of the renal artery (n = 1). After selective renal angiography, Embol was injected through various catheters, either with or without a balloon occlusion catheter. Changes in symptoms and blood chemistry which may have been related to renal artery embolization with Embol were analyzed. RESULTS: The six patients showed immediate total occlusion of their renal vas-cular lesions. One of the three in whom renal cell carcinoma was embolized with Embol underwent radical nephrectomy, and the specimen thus obtained revealed 40% tumor necrosis. In the two patients with angiomyolipomas, the tumors decreased in size and abdominal pain subsided. Bleeding from pseudoaneurysm of the renal artery was successfully controlled. Four patients showed symptoms of post-embolization syndrome, and one of these also showed increased levels of blood urea nitrogen and creatinine. One patient experienced transient hyperten-sion. CONCLUSION: Embol is easy to use, its radiopacity is adequate and it is a safe and effective embolic material which provides immediate and total occlusion of renal vascular lesions.

Preoperative Tract Dilatation for Percutaneous Nephrolithotomy

PURPOSE: The purpose of this study was to understand the principle of percutaneous nephrolithotomy(PNL), toincrease its success rate, and to base the radiologic approach on preoperative interventional tract dilatation. MATERIALS AND METHODS: Twenty-six patients(male, 19, female, 7) with staghorn or pelviocalyceal calculi who hadundergone PNL were included in this study. After percutaneous nephrostomy(PCN) was performed in each patient, thetract was dilated to 30F with Amplatz dilators using coaxial techniques or a 30F, 10cm high-pressure tractdilatation balloon. One day before the calculi were fragmented and removed by PNL, a 30F Amplatz sheath wasinserted under local anesthesia. The time required for tract dilatation, complications, and surgery was analyzed. RESULTS: Percutaneous tract dilatation were successful in all patients, and forceps, a nephrolithotome and anephroscope were successfully introduced into the pelvocalyceal system. The average procedure time was 19.5minutes ; a double J stent was replaced in the pelvocalyceal system of 13 of 26 patients (50%) ; because ofimproper catheter direction or/and bleeding, the Amplatz sheath was replaced in three. After PNL, complicationsinvolving renal hematoma occurred in one patient. This did not affect the patient's prognosis, however. CONCLUSION:Owing to its short procedure time and low complication rate, interventional preoperative tract dilatation forPNL is thought to be an effective technique for patients with staghorn or pelvocalceal calculi.

Renal Damage induced by Doxorubicin-Lipiodol Emulsion infused into Rabbit Renal Artery: Comparison with CT andHistologic Findings

PURPOSE: The purpose of this study was to evaluate the utility of renal CT scanning and to histologicallycorrelate renal damage induced by renal arterial infusion of 0.2 ml/kg of doxorubicin-lipiodol emulsion. MATERIALS AND METHODS: Renal CT scans of 20 rabbit kidneys were obtained 15 days after transcatheter arterialchemoembolization and were classified into four grades, as follows : Grade 0 - no fleck, Grade 1 - one to threenodular flecks ; Grade 2 - four or more nodular flecks, or one semilunar fleck ; and Grade 3 - two or moresemilunar flecks. The percentage of histological section occupied by lesion was determined using squared paper,and compared with the grades determined on the basis of CT. RESULTS: The histologic findings were interstitialinflammatory cell infiltration, intratubular lipiodol droplets, dystrophic calcification, and cellular necrosis.The mean sizes of grade 0, 1, 2 and 3 histological lesions were 2.2%(n=5), 4.5%(n=4), 21.9%(n=7), and 24%(n=4),respectively. Grades 0 and 1 accounted for nine cases(3.2%), while grades 2 and 3 accounted for 11(22.6%) ; thisdifference was statistically significant(p<0.01). CONCLUSION: CT findings showing nodular or semilunar flecks 15days after infusion into the renal artery of doxorubicin-lipiodol emulsion correlate with the size of the damagedkidney, as seen on histological specimens.

Acetic Acid Sclerotheraphy of Renal Cysts

PURPOSE: Sclerotherapy for renal cysts was performed, using 50% acetic acid as new sclerosing agent. Wereport the methods and results of this procedure. MATERIALS AND METHODS: Fifteen patients underwent sclerotherapyfor renal cyst, using 50% acetic acid. Because four patients were lost to follow-up, only 11 of the 15 wereincluded in this study. The renal cysts, including one infected case, were diagnosed by ultrasonograpy (n=10) ormagnetic resonance imaging (n=1). The patient group consisted of four men and seven women (mean age, 59 years;range, 23-77). At first, the cyst was completely aspirated, and 25 volume% of aspirated volume was replaced with50% sterile acetic acid through the drainage catheter. During the following 20 minutes, the patient changedposition, and the acetic acid was then removed from the cyst. Finally, the drainage catheter was removed, aftercleaning the cyst with saline. After treatment of infection by antibiotics and catheter drainage for 7 days,sclerotherapy in the infected case followed the same procedure. In order to observe changes in the size of renalcysts and recurrence, all patients were followed up by ultrasound between 2 and 8 months. We defined response totherapy as follows: complete regression as under 5 volume%, partial regression as 5-50 volume% and no response asmore than 50 volume% of initial cyst volume. RESULTS: No clinically significant complication occured during theprocedures or follow-up periods. All cysts regressed completely during follow-up of 8 months. Complete regressionoccurred as follows : two cysts at 2 months, seven cysts at 4 months, two cysts at 6 months. Two cysts showedresidues at the last follow-up, at 4 and 6 months, respectiivery. The volume of residual cysts decreased to under5 volume% of initial volume, however. Completely regressed cysts did not recurr during follow-up. CONCLUSION: Acetic acid sclerotherapy for renal cysts showed good results, regardless of the dilntion of sclersoing agent withresidual cyst fluid, and no significant complications. the procedure, therefore, appears to provide effectivetherapy for renal cysts.

A Comparative Study on Transcatheter Renal Arterial Embolization (TRAE) in Rabbits with Absolute Ethanol and Gelfoam Particles

PURPOSE: To evaluate the therapeutic effectiveness of absolute ethanol and gelfoam particles and the degree of vascular recanalization after gelfoam embolization. MATERIALS AND METHODS: Transcatheter renal arterial embolization(TRAE) was performal in 16 rabbits ; Eight were embolized with absolute ethanol, and eight with gelfoam particles. Of this total, three died less than one week after embolization. Pre- and post embolization angiographies at five minutes, one week, two weeks(gelfoam group only) and 5-6 weeks after embolization were performed. Six rabbits were sacrificed at one week, and seven at 5-6 weeks after embolization. Pathologic examination was performed. RESULTS: The ethanol group(n=6) showed complete occlusion of the main renal artery on follow-up angiography at one week and 5-6 weeks after embolization. The pathologic finding was complete total necrosis of embolized kidneys. The gelfoam group(n=7) showed partial recanalization of renal arteries in follow upangiography at one week, two weeks and 5-6 weeks after embolization. The pathologic finding was partial lysis ofgelfoam particles within intrarenal arteries. CONCLUSION: Absolute ethanol can be used as a permanent embolicagent and gelfoam as a temporary such agent in various clinical applications. Gelfoam, however, did not show complete recanalization on angiography and pathology at six weeks after embolization.