How can I locate, dissect, expose, and mobilize the left renal vein for creation of a proximal splenorenal shunt?

Surgical Technique for Left Renal Vein Exposure and Mobilization for Proximal Splenorenal Shunt

The left renal vein should be exposed through a transperitoneal approach with midline or left subcostal incision, mobilizing the left colon medially and dissecting the renal vein from its origin at the inferior vena cava to its entry into the renal hilum, ensuring adequate length (typically 4-6 cm) for tension-free anastomosis to the splenic vein. 1, 2

Patient Positioning and Initial Access

• Position the patient supine on the operating table with the left side slightly elevated (15-30 degrees) to improve access to the left upper quadrant 3
• Use a midline laparotomy incision extending from xiphoid to umbilicus, or alternatively a left subcostal incision for more direct access 4
• Avoid excessive lateral positioning or "rolling" of the table, as this increases risk of splenic capsular injury during left-sided dissection 5

Exposure of the Left Renal Vein

Step 1: Mobilize the left colon

• Incise the white line of Toldt along the lateral peritoneal reflection of the descending colon 3
• Reflect the left colon and mesocolon medially to expose the retroperitoneum 3
• This maneuver provides access to the anterior surface of Gerota's fascia and the underlying renal vessels 3

Step 2: Identify anatomic landmarks

• Locate the inferior mesenteric vein as it crosses anterior to the left renal vein—this serves as a key landmark 4
• The left renal vein runs horizontally from the renal hilum to the inferior vena cava, typically at the level of L1-L2 vertebrae 3
• Identify the aorta medially and the inferior vena cava as reference points 6

Step 3: Dissect the left renal vein

• Begin dissection at the renal hilum where the vein is most superficial and easily identified 4
• Use careful blunt and sharp dissection to expose the anterior surface of the left renal vein from the renal hilum laterally to its junction with the inferior vena cava medially 6
• Ligate and divide small tributaries including the left gonadal vein (inferiorly), left adrenal vein (superiorly), and lumbar veins (posteriorly) to achieve complete mobilization 6
• Critical: Preserve the main renal vein trunk and avoid injury to these collateral pathways until you have confirmed adequate alternative venous drainage 6

Assessment of Renal Vein Suitability

Before proceeding with anastomosis, measure the left renal vein stump pressure if division is contemplated—pressures below 60 cm H₂O indicate adequate collateral drainage and safe division 6

• Assess the length of the mobilized left renal vein—a minimum of 4-5 cm of mobilized vein is needed for tension-free anastomosis 4, 7
• Evaluate the caliber match between the splenic vein and left renal vein—significant size mismatch may require technical modifications 4
• If the left renal vein is anomalous, has inadequate length, or shows poor outflow on preoperative venography, consider alternative shunt techniques such as splenocaval shunt or interposition grafts 4, 7

Common Pitfalls and Technical Considerations

Anatomic variations occur in up to 15% of patients and must be identified preoperatively:

• Retroaortic or circumaortic left renal vein variants may complicate dissection 4
• Multiple renal veins may be present and require individual assessment 4
• Preoperative CT angiography with venous phase imaging is essential to map venous anatomy before surgery 3, 4

Hemostasis is critical:

• The portal venous system operates at high pressure, making meticulous control of all venous tributaries essential 1
• Use fine vascular sutures (5-0 or 6-0 polypropylene) for vessel repair if injury occurs 1
• Have vascular clamps readily available for proximal and distal control 1

Intraoperative monitoring:

• Measure portal pressure before and after shunt creation—target reduction of at least 20% or to below 12 mm Hg 1
• Confirm adequate renal perfusion by palpating the kidney for turgor and observing urine output 6

Postoperative Surveillance

• Perform Doppler ultrasound at one week to confirm shunt patency, particularly in patients with prothrombotic conditions 1
• Repeat Doppler ultrasound at 6-12 month intervals for long-term monitoring 1
• Monitor renal function with serum creatinine and urinalysis in the immediate postoperative period, as transient left renal dysfunction may occur 6