Renal Vascular Anatomical Variants: Why 3D Models Are Essential

Anatomy is never truly standard

In anatomy textbooks, the kidney has one artery and one vein. In clinical reality, vascular variants are the rule, not the exception. It is estimated that more than 30% of patients present some form of renal vascular variant.

For a surgeon planning a nephrectomy, identifying these variants before surgery can make the difference between a smooth operation and an intraoperative complication.

Most common variants

Accessory renal arteries

The presence of multiple renal arteries is the most frequent variant. They may arise from the aorta at different levels and supply specific kidney portions - especially the upper and lower poles. Clamping that does not account for an accessory artery can cause ischemia in a renal segment.

Renal vein duplication

The renal vein may appear duplicated, with two distinct branches draining into the caval system. This variant is especially relevant in left kidney surgery, where the renal vein crosses the midline.

Circumaortic renal vein

An important variant in which the renal vein forms a ring around the aorta, with an anterior and a posterior branch. This configuration carries significant risk of venous injury during renal hilum dissection.

Early-branching segmental arteries

In some patients, segmental arteries branch very early from the main renal artery, sometimes before entering the hilum. This radically changes selective clamping strategy.

The limit of two-dimensional CT

Contrast-enhanced CT images can visualize these variants, but interpretation requires careful analysis of axial, coronal, and sagittal sections. The surgeon must mentally reconstruct vessel tridimensionality - a process that depends on individual experience and introduces variability.

The problem is especially evident when:

Vascular structures overlap on a single imaging plane
Arterial tortuosity makes vessel course tracking difficult
Spatial relationships between tumor mass and segmental vessels are not obvious

The 3D model advantage

With an interactive 3D model, the surgeon can:

Freely rotate the model to appreciate the full course of each vessel
Isolate structures by toggling individual anatomical layers (arteries, veins, urinary tract, tumor)
Adjust opacity to visualize relationships between deep and superficial structures
Measure distances between the tumor mass and main vessels

These capabilities turn a subjective mental reconstruction into an objective, shareable exploration.

Real clinical cases

In our case series, vascular variants had a direct impact on surgical planning:

A case of vena cava duplication with a renal cyst near the hilum required particularly careful planning to avoid vascular complications
A case of renal vein duplication in which the renal artery coursed between the two venous branches, with a tumor adjacent to a segmental branch
A case of circumaortic renal vein with significant renal artery tortuosity and early-branching segmental arteries in the lower pole

In each of these cases, the 3D model allowed confident variant identification and planning of the safest surgical approach.

Conclusions

Vascular anatomical variants are not rare exceptions: they are a daily reality of renal surgery. 3D models do not create them - they make them visible, measurable, and communicable. For surgeons, this means greater safety. For patients, a more precise and less risky procedure.