Therapy-resistant nephrolithiasis following renal artery coil embolization

Thulium laser extraction of angioembolization coils in patient presenting with nephrolithiasis: A case report

Renal Artery Embolization (RAE) is a first-line treatment for arteriovenous fistula complications, which may occur following percutaneous nephrolithotomy (PCNL). A rare complication of RAE is metal coil migration, which may present with nephrolithiasis symptoms, including hematuria and flank pain. Imaging like Computed Tomography (CT) Angiography can help assess the risk of hemorrhage due to coil location relative to vasculature. Subsequently, ureteroscopy can be done with thulium laser excision of the coils and lithotripsy of adherent stone. This case is one of the first to demonstrate that endourological thulium laser excision is a safe and effective management for migrated angioembolization coils.

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.

Assessment of the embolization effect of temperature-sensitive p(N-isopropylacrylamide-co-butyl methylacrylate) nanogels in the rabbit renal artery by CT perfusion and confirmed by macroscopic examination

Transcatheter embolization is an important treatment method in clinical therapy, and vascular embolization material plays a key role in embolization. The temperature-sensitive p(N-isopropylacrylamide-co-butyl methylacrylate) (PIB) nanogel is a novel embolic agent. To evaluate the feasibility of the nanogel as a blood vessel embolization agent, we aimed to assess the effect of embolization with PIB nanogels in the rabbit renal artery by non-invasive computed tomography (CT) perfusion, macroscopic and histological examination. Ten healthy adult Japanese rabbits were used to implement RAE of PIB nanogels in their right kidneys. CT perfusion scans were performed pre- and post-treatment at various time-points (1, 4, 8, and 12 weeks). Two rabbits were euthanized and histologically examined at each time-point, and the remaining rabbits were euthanized at 12 weeks after embolization. The RAE efficacy of the nanogels was further confirmed by macroscopic and histological examination. The renal volume and renal blood flow (BF) of the right kidney were significantly decreased post-treatment compared with those pre-treatment (volume: pre, 9278 ± 1736 mm³; post 1 week, 5155 ± 979 mm³, P < 0.0001; post 4 weeks, 3952 ± 846 mm³, P < 0.0001; post 8 weeks, 3226 ± 556 mm³, P < 0.0001; post 12 weeks, 2064 ± 507 mm³, P < 0.0001. BF: pre, 530.81 ± 51.50 ml/min/100 ml; post 1 week, 0 ml/min/100 ml, P < 0.0001; post 4 weeks, 0 ml/min/100 ml, P < 0.0001; post 8 weeks, 0 ml/min/100 ml, P < 0.0001; post 12 weeks, 0 ml/min/100 ml, P < 0.0001). No revascularization or collateral circulation was observed on histological examination during this period, and PIB nanogels were dispersed in all levels of the renal arteries. Twelve weeks after embolization, CT perfusion showed no BF in the right renal artery and renal tissue, a finding that was consistent with histological examination showing complete embolization of the right renal artery with a lack of formation of collateral vessels. The effect of embolization on PIB was adequate, with good dispersion and permanency, and could be evaluated by non-invasive and quantitative CT perfusion.

Endourologic Treatment of Late Migration of Embolization Causing Nephrolithiasis in Two Patients

Background: Selective renal artery angioembolization is the first treatment option in case of significant bleeding after percutaneous nephrolithotomy. Migration of embolization material into the collecting system is extremely rare. The treatment of this condition is not standardized, but manual extraction, ultrasound fragmentation, and holmium laser lithotripsy have been described. Case presentation: We report the laser extraction of these coils in two patients at our center with two different approaches: retrograde intrarenal surgery (RIRS) and endoscopic combined intrarenal surgery (ECIRS). They were young male patients aged 25 and 29 years at the time of surgery, and they were 2-5 years postembolization when they presented to our center for symptoms such as hematuria and passage of small stone fragments. The first patient was managed solely with RIRS, whereas the second patient required ECIRS because of significant bleeding after coil removal, which necessitated hemostasis using a resectoscope. Conclusion: For patients who present with recurrent stones or other symptoms such as pain, hematuria, or flank pain, the diagnosis of migrated embolization coils should be considered. Management can be via the retrograde or percutaneous approach, but in the setting of significant amount of migrated coils or significant bleeding after their removal, percutaneous access may allow more definitive hemostasis.

Simultaneous Ureteral and Renal Foreign Bodies

Clinical presentation of patients with foreign bodies is highly variable. We received a 55-year-old female patient with fever and right flank pain. She was treated previously for kidney stones by percutaneous nephrolithtomy with partial resolution, requiring renal embolization during this procedure because of bleeding. CT evidenced metallic density images localized in kidney and ureter, associated with kidney stones located in lower calix. Semirigid ureteroscopy and retrograde intrarenal surgery were performed, revealing the presence of foreign bodies in both localizations and lower calix stones. Complete removal of foreign bodies and stones was performed. Foreign bodies were found to be embolization coils applied in the previous procedure.

Massive migration of embolization coils inside the renal pelvis. A rare complication that can be approached through percutaneous surgery

Percutaneous nephrolithotripsy (PCNL) has become a common procedure performed in patients with large renal calculi. Hemorrhage is the most frequent complication of this procedure. Transcatheter renal artery embolization is an effective and minimally invasive treatment option for acute renal bleeding but it is not without risks. In the case we describe, a big stone originated on embolization coils which migrated inside the renal pelvis after a previous PCNL and transcatheter artery embolization. We show that a new percutaneous approach is feasible and allows for the fragmentation of the stone and full clearance of fragments and coils.

Renal artery embolization-indications, technical approaches and outcomes

Owing to improvements in catheters and embolic agents, renal artery embolization (RAE) is increasingly used to treat nephrological and urological disease. RAE has become a useful adjunct to medical resuscitation in severe penetrating, iatrogenic or blunt renal traumatisms with active bleeding, and might avoid surgical intervention, particularly among patients that are haemodynamically stable. The role of RAE in pre-operative or palliative management of advanced malignant renal tumours remains debated; however, RAE is recommended as a first-line therapy for bleeding angiomyolipomas and can be used as a preventative treatment for angiomyolipomas at risk of bleeding. RAE represents an alternative to nephrectomy in various medical conditions, including severe uncontrolled hypertension among patients with end-stage renal disease, renal graft intolerance syndrome or autosomal dominant polycystic kidney disease. RAE is increasingly used to treat renal artery aneurysms or symptomatic renal arteriovenous malformations, with a low complication rate as compared with surgical alternatives. This Review highlights the potential use of RAE as an adjunct in the management of renal disease. We first compare and contrast the technical approaches of RAE associated with the various available embolization agents and then discuss the complications associated with RAE and alternative procedures.