Normally, the left renal vein lies over the anterior surface of the abdominal aorta, usually at the level of the renal arteries orifices, or sometimes at a bit lower level. However, in less than 1% of the AAA cases, the left renal vein may lie posteriorly to the aorta, being a retroaortic left renal vein. Is it of some importance? Sure, it is. As there is a great danger of damaging either with the aortic clamp or when dissecting close to the aorta or even when sewing the graft on the aorta.
Here are some thoughts about it:
- It is said that the best approach would be through a retroperitoneal approach of the aorta or an approach from its posterior area. This may be correct as the surgeon will have a clear view of the retroaortic renal vein and will be able to deal with it, either protecting it or dividing it.
- However, an anterior approach can be done. Definitely, it is necessary to have carefully evaluated the preoperative CT scan, identify the level where it lies as compared to the aorta, and trying to be away from it.
Today, we had such a case, Mr NL, 66. He suffered by an infrarenal AAA extending to both common iliac arteries. The retroaortic left renal vein was about 1 cm below the lowest (right) renal artery, as seen in the CT scan. I decided to carry on with the usual anterior approach. I decided to put the aortic clamp above the right renal artery so as to be sure that I will not cause any tear on the vein. And this happened, leading to an uneventful case.
Of course, I have to underline that although I was with two junior residents for the anatomic dissections (AT and JT), when I had to open the aorta and make the anastomosis I called for my colleague Mr GS who helped me to carry on a relatively relaxing case.