[High ureteral insertion as the cause of extreme hydronephrosis in a 5-year-old child with horseshoe kidney]

The incidence of horseshoe kidney is 1 per 400-800 live births. From 44-52% of the patients with horseshoe kidney have other coexisting abnormalities of the urinary tract, such as hydronephrosis, vesicoureteral reflux and a duplex collecting system. Our patient, a 5-year old boy, was admitted to a pediatric nephrology department because of abdominal pain and vomiting. He had ultrasonography of the abdomen performed for the first time at the age of 9-months and horseshoe kidney was shown. In a control ultrasonography, a mild dilatation of the pyelocalyceal system in the left kidney was described. On the day of admission, an abdominal ultrasound confirmed horseshoe kidney with large left hydronephrosis. Power Doppler ultrasonography showed two renal arteries to the left kidney and no arterial compression on the ureter. Dynamic scintigraphy (99mTc-EC) revealed left-sided hydronephrosis with high isotope intake up to 55% ERPF, a prolonged time of tissue perfusion and signs of subpelvic junction obstruction. Magnetic resonance urography presented an enlarged left kidney, with a diameter of up to 105 mm, a narrow renal cortex, a dilated renal pelvis up to 39 mm in diameter, dilated calyces up to 26-32 mm, and the high insertion of the ureter from the pelvis. The right kidney was normal. To facilitate drainage from the dilated collecting system of the left kidney, a double-J catheter was inserted. Pyeloplasty is planned as the next step of treatment. Conclusion: In a child with horseshoe kidney and a mild dilatation of the collecting system detected in infancy, long-term follow up is necessary, because of the increased risk of significant hydronephrosis in the future.

Reviewing the complexities of horseshoe kidney: insights into embryogenesis and surgical considerations

Horseshoe kidney (HSK) is a common renal malformation with unique and complex characteristics. A systematic literature search was conducted using PubMed and ScienceDirect databases. Several theories have been proposed regarding HSK formation, such as the close apposition of the kidneys during ascent through an arterial fork, lateral flexion of the trunk, and caudal embryonic rotation. Emerging evidence from animal models implicates notochord signaling and the sonic hedgehog pathway in HSK formation. The isthmus, a defining feature of HSK, is hypothesized to arise from ectopic mesenchymal tissue. The surgical anatomy of HSK is complex, given the variability in location, orientation, and blood supply. Both arterial and venous anatomy exhibit significant variability, raising questions about whether anomalous blood supply is a cause or a consequence of abnormal renal position. The isthmus usually contains functional renal parenchyma and fusion between the kidneys, primarily at the lower pole. While it is often stated that the inferior mesenteric artery is "held back" at the L3 level, this anatomical configuration is present in only 40% of cases. The review highlights the need for further research and provides a comprehensive overview of HSK knowledge.

Preemptive treatment of type II endoleak for abdominal aortic aneurysm with renal fusion (horseshoe kidney)

OBJECTIVE

To assess viability and safety of preemptive treatment of type II endoleak for abdominal aortic aneurysm (AAA) repairs.

METHODS

A 69-year-old man with renal fusion (horseshoe kidney) was referred for treatment of a 5.5 cm AAA. His anatomy was suitable for endovascular repair. The risk for type II endoleak was increased because of multiple infrarenal arterial orifices originating within the aneurysm sac. These included an accessory renal artery that supplied the renal isthmus, a patent inferior mesenteric artery, and a pair of large lumbar arteries originating from a single orifice (8 mm) at L3 spinal level. The lumbar orifice was selectively cannulated and occluded with thrombogenic coils 1 week prior to his endovascular aneurysm repair.

RESULTS

Aneurysm repair was uneventful with no signs of early or delayed endoleak and long-term follow-up of 5 years.

CONCLUSIONS

Preemptive coil embolization of perianeurysmal arteries may be considered as a safe and effective strategy for management of potential type II endoleak.