Hybrid Management for Anterior Nutcracker Syndrome: Left Renal Vein Stenting with Laparoscopic Stent Exofixation

Left renal vein stenting (LRVS) was reported for the first time by Neste in 1996 for the treatment of anterior nutcracker syndrome (NCS). Nowadays, this technique is the first choice treatment for symptomatic NCS over invasive open surgical procedures. The most serious complication of the LRVS is intracaval or right ventricular stent migration. Here hybrid management is described for the treatment of anterior NCS (Fig. 1) associating an LRVS with laparoscopic stent exofixation during the same procedure. This strategy aims to eliminate the risk of stent migration.

LRVS has now replaced open surgery as the first choice treatment for anterior NCS, thanks to its good long term results^, and less invasive approach. However, the most serious complication of this procedure is stent migration into the IVC or right ventricle. According to the three largest series of endovascular treatment for NCS (30, 61, and 75 patients), stent migration occurred in 4.9%–6.7% of cases between the immediate post-operative period and several months after the intervention.^,, The stent can sometimes be retrieved easily with a snare catheter. In other cases, its extraction requires cardiac surgery. Two cases of tricuspid valve replacement have been reported.^,

Because of the narrow aortomesenteric angle and the aortic pulse, the left renal vein stent deployed at aortomesenteric level acts like a bar of soap. The hypothesis is that every aortic pulse would weaken the stent anchoring in the venous wall, until migration. This inconvenience necessitated development of a new hybrid technique in order to avoid the stent migration.

Laparoscopic stent exofixation limits the risk of migration and is a low morbidity procedure. This strategy consists of anchoring the stent to the left renal vein with a unique and simple transfixing polypropylene stitch put through one of its meshes. The TPD approach has been described. Two other laparoscopic approaches exist: transperitoneal retrocolic (TPRC) and retroperitoneoscopic (RP).^, Through these three approaches, the entire LRV is exposed without mobilising the left kidney. The transperitoneal left retrorenal approach (TPRR) should be avoided because the kidney rotation to the right, associated with a LRV mobilisation, potentially induces stent migration. The best approach depends on the medical history, anatomical variants, and morphology of the patient. In most cases, those who present an anterior NCS have little intra-abdominal and retroperitoneal fat, including mesentery and perirenal fat. For these patients without a history of abdominal surgery, the TPD approach seems to be the safest and fastest approach. Right lateral decubitus is sufficient to move the small bowel to the right in order to obtain a large and stable operative space. The TPD approach does not mobilise the LRV and limits the dissection. The two other approaches (TPRC and RP) are also possible but increase the risk of mesocolic breach. For obese patients, the TPD approach can be challenging because of the volume of intra-abdominal fat and the difficulty keeping the small intestine to the right. In this case, the TPRC approach allows a good and stable exposure of the operative space. For patients with a history of abdominal surgery, the RP approach allows sufficient visualisation of the LRV to place a stitch for the stent exofixation. Its main disadvantages are a reduced operative space and a conflict between laparoscopic instruments if the distance between left rib cage and iliac crest is short.

The left pelvic varicose veins can be managed by pre-operative embolisation or an intra-operative clip ligation of the left gonadal vein during the laparoscopic procedure. Furthermore, the stent exofixation allows use of a short stent in order to preserve the left gonadal vein ostium if a subsequent embolisation is scheduled.

The risk of migration could also be reduced by using intravascular ultrasound (IVUS) to accurately measure the LRV diameter at the aortomesenteric portion. An important stent oversizing is still needed and is associated with the risk of intimal hyperplasia and subsequent intrastent re-stenosis. Laparoscopic stent exofixation decreases this oversizing and limits these complications and the risk of stent migration.

Hybrid treatment associating LRVS and laparoscopic stent exofixation during the same procedure is a quick, simple, and low morbidity technique. Its purpose is to avoid the risk of stent migration into the IVC or right ventricle. Further follow up data are needed to evaluate this technique in reducing the risk of this severe complication.