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A varicocele is almost always the result of compression of a left renal vein

Unfortunately, it is little known that a varicocele is primarily caused by compression of the left renal vein.

This compression leads to an increase in pressure in the left renal vein and subsequently in the left spermatic vein. The increasing pressure causes dilation of the pampiniform venous plexus in the scrotum, which surrounds the testicle.

In the vast majority of cases, the left testicle is affected alone or first. The reason for this is that left renal vein compression is the most common of all abdominal compression syndromes. The pressure is transmitted directly to the left testicle. The right spermatic vein is connected to the pelvic venous plexus that surrounds the prostate, but drains directly into the inferior vena cava. Thus, after congestion of the left half of the pelvis and the left testicle, the pressure can also be transferred to the right testicle, resulting in a right varicocele.

It is therefore necessary to rule out vascular compression in patients with varicoceles. Otherwise, recurrence after ligation of the spermatic vein is very likely. The correct treatment would then be to restore the left renal outflow. Obstruction of the collateral pathway via the left spermatic vein deprives the left renal vein of its outflow pathway. The obligatory consequence is an increase in pressure and thus pain in the vascular area of the left renal vein and the formation of new collaterals, often again via the left testicle.

The following case is an instructive example:

Severe left renal vein compression in a patient with left-sided varicocoele

Development of multiple enlarged and winding left spermatic veins as an attempt of the body to circumvent the compression site of the left renal vein by bypassing the blood via the left testicle towards the vena cava inferior

The video above shows a black and white ultrasound examination (B-mode ultrasound) demonstrating the large and wormlike varicose veins of the pampiniform plexus above the upper pole of the left testicle-atypical varicocele

The varicocele is however much better examined by colour Doppler ultrasound as shown in the video above. colour Doppler allows a flow quantification with the PixelFlux technique. Such measurements are the basis for an exact evaluation of the severity of the disease and moreover can precisely describe the effect of any treatment.

Exact quantification of the blood flow in the pampiniform plexus and the testicle left and right by the PixelFlux measurement

With the PixelFlux measurement, it can be precisely calculated that the flow volume in the left pampiniform plexus is 7 times higher than in the right, while the blood flow in the left testicle is 3 times higher than in the right.

Not only allows PixelFlux to quantify the varicocele itself but also the underlying left renal vein compression which is demonstrated in the following diagram:

PixelFlux measurement of the left and right renal perfusion

The renal perfusion measurement with the PixelFlux technique shows that the high pressure in the left renal vein cannot be compensated by the circumvention of blood across the left testicle since even though the left kidney receives only 68% of the blood flow volume of the right kidney. Thus, not only the left testicle but also the left kidney is suffering.

Normal right testicle of the same patient in the video above.

Accordingly, the blood flow within the pampiniform plexus of the right testicle is significantly lower.