Case Report Stone Formation from Nonabsorbable Clip Migration into the Collecting System after Robot-Assisted Partial Nephrectomy Ziho Lee, 1 Christopher E. Reilly, 1 Blake W. Moore, 1 Jack H. Mydlo, 1 David I. Lee, 2 and Daniel D. Eun 1 1 Department of Urology, Temple University School of Medicine, 255 S 17th Street, Suite #2101, Philadelphia, PA 19103, USA 2 Division of Urology, University of Pennsylvania School of Medicine, Philadelphia, PA, USA Correspondence should be addressed to Daniel D. Eun; daniel.eun@tuhs.temple.edu Received 19 December 2013; Accepted 20 January 2014; Published 23 February 2014 Academic Editors: A. Goel, S. K. Hong, C. Liao, and F. Ramezanzadeh Copyright © 2014 Ziho Lee et al. his is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. We describe a case in which a Weck Hem-o-lok clip (Telelex, Research Triangle Park, USA) migrated into the collecting system and acted as a nidus for stone formation in a patient ater robot-assisted partial nephrectomy. he patient presented 2 years postoperatively with let-sided renal colic. Abdominal computed tomography scan showed a 10 millimeter renal calculus in the let middle pole. Ater using laser lithotripsy to fragment the overlying renal stone, a Weck Hem-o-lok clip was found to be embedded in the collecting system. A laser iber through a lexible ureteroscope was used to successfully dislodge the clip from the renal parenchyma, and a stone basket was used to extract the clip. 1. Introduction Renorrhaphy is a time-sensitive and technically challenging aspect of robot-assisted partial nephrectomy (RPN). As such, the sutures used for kidney closure are commonly secured in place with a surgical clip [1], rather than conventional knot tying. A rare postoperative complication associated with this technique is migration of the surgical clip into the urinary tract, which may cause signiicant morbidity for patients [2– 4]. Herein, we describe a case in which a Weck Hem-o-lok clip (Telelex, Research Triangle Park, USA) migrated into the collecting system and acted as a nidus for stone formation ater RPN. 2. Case Report A 52-year-old man with a history of nephrolithiasis and prostate cancer ater robot-assisted radical prostatectomy presented with a small let renal mass. Abdominal computed tomography (CT) scan with and without contrast showed an enhancing 3 centimeter (cm) let middle pole renal mass that was noted to have increased in size since a prior CT scan. Subsequently, the patient underwent an uneventful let RPN. he renorrhaphy was completed in a single layer using a running 3-0 Vicryl (Ethicon, Somerville, USA) suture which was secured in place with Weck Hem-o-lok clips using sliding clip technique. Hemostasis was achieved without the use of any hemostatic agents or bolsters. he patient’s postoperative course was complicated by a perinephric hematoma that was diagnosed by CT scan. Renal angiography was negative for active bleeding, and the patient was managed with blood transfusions and close observation in the intensive care unit. Pathology indicated a 2.4 cm clear cell renal cell carcinoma, Fuhrman grade II, and negative surgical margins. Two years ater RPN, the patient presented with let- sided colicky lank pain. Noncontrast helical abdominal CT scan showed a 6 millimeter (mm) let ureteral stone and a 10 mm let middle pole stone, associated with mild let hydroureteronephrosis. Ater the patient was acutely managed with let ureteral stent placement, he later under- went extracorporeal shock wave lithotripsy, which did not completely resolve his stone burden (Figure 1). he patient then underwent let lexible ureteroscopy that revealed the 10 mm renal calculus, which was adherent to the middle pole (Figure 2). Upon successful fragmentation of the stone Hindawi Publishing Corporation Case Reports in Urology Volume 2014, Article ID 397427, 3 pages http://dx.doi.org/10.1155/2014/397427