From the case:
Avascular plane of Brodel (diagram)
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The path of the needle indicates the so-called "avascular plane of Brodel".
Case Discussion
The renal artery divides into anterior and posterior branches. The relative paucity of blood vessels in the posterior aspect of the renal parenchyma creates the so-called "avascular plane of Brodel". This plane is located just posterior to the lateral convex border of the kidney. It permits a relatively safe access route to the pelvicalyceal system for nephrostomy insertion.