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Case Report

assage of Embolization Coil Throughrinary Collecting System One Yearfter Embolization

manda Reed, Rajeev Suri, and Robert Marcovich

ascular injury is an uncommon, but serious, complication of percutaneous nephrolithotomy. Hyperselective angio-mbolization is an effective means of managing this complication with few reported adverse sequelae. We report a casen which an embolization coil placed after renal hemorrhage subsequently eroded into the collecting system more thanyear postoperatively and was passed through the patient’s urinary tract. UROLOGY 70: 1222.e17–1222.e18, 2007. © 2007

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evere renal hemorrhage is one of the most seriouscomplications of percutaneous nephrolithotomy(PCNL),1 reportedly occurring in 3% to 14% of

ases.2 It can require selective percutaneous transarterialmbolization in 1% to control bleeding.2,3 The compli-ations of renal percutaneous transarterial embolizationre uncommon.4 We report a case of delayed erosion ofn embolization coil from the renal parenchyma into therinary collecting system and later passage of the coil infashion similar to passage of a ureteral stone.

ASE REPORT50-year-old woman had undergone uncomplicated left

CNL for a 2.5-cm renal pelvic calculus in July 2005. Sixays after nephrostomy tube removal, the patient expe-ienced self-limited gross hematuria. Several days later,ross hematuria with clot retention and a significantecrease in her hemoglobin level occurred, necessitatingngiography (Fig. 1). This revealed an arteriovenous fis-ulous communication from two lower pole branches ofhe renal artery, with an approximately 1-cm pseudoan-urysm arising from one of the arteriovenous fistulas.hree 6-mm coils were positioned in the pseudoaneu-

ysm, proximal and distal to the neck of the aneurysm.n arteriovenous fistula, from the adjacent lower pole

ranch, was embolized with two 5-mm coils. A subse-uent angiogram demonstrated no residual arteriovenousstula. The patient tolerated the procedure without acuteomplications and was subsequently discharged. Eightonths later, the patient underwent plain abdominal

adiography as a part of routine follow-up that showed noew calculi.

rom the Departments of Urology and Radiology, University of Texas Health Scienceenter, San Antonio, TexasAddress for correspondence: Amanda Beth Reed, M.D., Department of Urology,niversity of Texas Health Science Center, Mail Code 7845, 7703 Floyd Curl Drive,

ban Antonio, TX 78229-3900. E-mail: reeda2@uthscsa.eduSubmitted: April 30, 2007, accepted (with revisions): September 12, 2007

2007 Elsevier Inc.ll Rights Reserved

More than 1 year after PCNL and renal embolization,he patient presented to the emergency department witheft renal colic and intermittent hematuria, nausea, andomiting. Plain abdominal radiography (Figs. 2 and 3)nd noncontrast abdominopelvic computed tomographyere performed, both showing a metallic coil at the leftreterovesical junction. The patient was treated expect-ntly with subsequent passage of the coil, as verified byepeat plain abdominal radiography.

OMMENThe potential consequences of coil erosion or migration

nto the collecting system include significant renal hem-rrhage, as well as all the sequelae associated with foreign

igure 1. Placement of embolization coils during acuteemorrhage.

odies in the urinary tract. These include encrustation,

0090-4295/07/$32.00 1222.e17doi:10.1016/j.urology.2007.09.007

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nfection, obstruction, hematuria, and fistula formation.n our patient’s case, the only symptoms were renal colicnd mild gross hematuria, which likely resulted fromrritation of the urothelium by the foreign body. These

igure 2. Plain radiograph 1 year after selective renal em-olization demonstrating coils visible overlying left renalhadow and in left proximal ureter adjacent to lumbarertebrae.

igure 3. Subsequent distal migration of coil down to leftreterovesical junction.

ymptoms resolved with spontaneous passage of the coil.

222.e18

he mechanism of arteriovenous fistula formation afterCNL is most often linked to the forceful dilation of thealix, with consequent division of the caliceal wall, ex-osing the underlying vessels. After coil embolization,ealing of the caliceal wall over the coils can result in

ocal areas of weakness through which the coil can mi-rate into the urinary collecting system.

Three potential mechanisms of coil erosion can beypothesized in this case according to the estimated timet which the coil eroded into the collecting system. First,he arteriocaliceal communication might have beenarger than the embolization coil at embolization, and theoil extruded through the communication soon afterlacement. The coils used to embolize vascular lesionsre expected to be larger than the vascular defect so thato migration occurs through the defect. However, noefinitive method is available to measure the vascularefect. Second, the arteriocaliceal communication couldave widened over time because of inflammation fromrine, infection, or the constant irritation from the in-welling coil itself, leading to eventual erosion into theollecting system. Finally, a microscopic arteriocalicealommunication could have been present that suddenlyidened or ruptured owing to the weakened pseudo-wallf a pseudoaneurysm exposed to high arterial pressures.ith the latter mechanism, significant gross hematuria

ould be anticipated.

ONCLUSIONSo our knowledge, no previous cases of embolization coiligration into the renal collecting system with subse-

uent ureteral passage have been reported in urologic oradiologic studies. The present patient was treated sup-ortively and experienced no delayed adverse sequelae.

eferences. Gallucci M, Fortunato RP, Schettini M, et al: Management of

hemorrhage after percutaneous renal surgery. J Endourol 12: 509–512, 1998.

. Ramchandani P, Cardella JF, Clement JG, et al: Quality improve-ment guidelines for percutaneous nephrostomy. J Vasc Interv Radiol12: 1247–1251, 2001.

. Kessaris DN, Bellman GC, Pardalidis NP, et al: Management ofhemorrhage after percutaneous renal surgery. J Urol 153: 604–608,1995.

. Vignali C, Lonzi S, Bargellini I, et al: Vascular injuries after percu-taneous renal procedures: treatment by transcatheter embolization.

Eur Radiol 14: 723–729, 2003.

UROLOGY 70 (6), 2007