Therapy-Resistant Nephrolithiasis Following Renal Artery Coil Embolization

Cédric Poyet; Florian Grubhofer; Matthias Zimmermann; Tullio Sulser; Thomas Hermanns


BMC Urol. 2013;13(29) 

In This Article

Abstract and Introduction


Background Transcatheter renal artery embolization is an effective and minimally invasive treatment option for acute renal bleeding. Early post-interventional complications include groin hematoma, incomplete embolization, coil misplacement and coil migration. Late complications are rare and mostly related to coil migration.

Case presentation A 22-year-old woman with a history of recurrent stone disease and a lumbal meningomyelocele underwent bilateral open pyelolithotomy for bilateral staghorn calculi. Post-operatively, acute hemorrhage of the left kidney occurred and selective arterial coil embolization of a lower pole interlobular renal artery was performed twice.

Four years after this intervention the patient presented with a new 15.4 mm stone in the lower calyx of the left kidney. After two extracorporeal shock wave lithotripsy treatments disintegration of the stone was not detectable. Therefore, flexible ureterorenoscopy was performed and revealed that the stone was adherent to a partially intraluminal metal coil in the lower renal calyx. The intracalyceal part of the coil and the adherent stone were successfully removed using the holmium laser.

Conclusion Therapy-resistant nephrolithiasis was caused by a migrated metal coil, which was placed four years earlier for the treatment of acute post-operative renal bleeding. Renal coils in close vicinity to the renal pelvis can migrate into the collecting system and trigger renal stone formation. Extracorporeal shock wave lithotripsy seems to be inefficient for these composite stones. Identification of these rare stones is possible during retrograde intrarenal surgery. It also enables immediate stone disintegration and removal of the stone fragments and the intraluminal coil material.


Renal artery embolization (RAE) was initially developed in the 1970s for symptomatic renal haematuria and palliation for unresectable renal tumours.[1] Nowadays, RAE is a widely used, minimally invasive treatment option for various renal or vascular diseases. The most common indications for RAE are palliation of unresectable renal tumors, treatment of renal angiomyolipomas, renal arterio-venous fistulae, renal artery aneurysms, vascular malformations and life threatening or chronic renal hemorrhage. Furthermore, it is used for infarction of renal tumors prior to nephrectomy or radiofrequency ablation.[2] A variety of embolic agents such as metal coils, particulate or sclerosants agents (liquids, foams) are available. The selection of the embolic material depends on several factors such as vessel size, vascular anatomy and hemodynamics. In the case of acute renal hemorrhage, metal coils are most often used.[3]

One possible complication of RAE is migration of these metal coils into the collecting system.[4] Coils that migrated completely into the collecting system have been reported to cause symptomatic ureteric obstruction.[5–7] To the best of our knowledge, stone formation after coil migration has so far only once been described before.[8] We report a case of a partly migrated renal metal coil leading to therapy-resistant nephrolithiasis.