Immediate and delayed migration of Onyx embolisation into the renal collecting system

We present a case of Onyx embolisation of a renal pseudoaneurysm following partial nephrectomy with collecting system involvement with subsequent migration of Onyx into the renal collecting system resulting in renal obstruction. This occurred both immediately after embolisation and again 8 years after embolisation. Both cases required ureteroscopic surgical intervention. In the first instance, the pieces were removed using basket extraction. In the second, laser lithotripsy was used in addition to basket extraction. While there are a few cases of embolisation coils eroding into the renal collecting system, this is the second reported case of Onyx migration and the first where ureteroscopy with laser lithotripsy was used. The patient is doing well and undergoing surveillance ultrasounds to ensure there is no further Onyx migration. This may be a consideration for patients with pseudoaneurysm embolisation especially in the setting of prior collecting system damage.