Freeing up the splenic vein from its pancreatic bed is usually quite difficult because of the many delicate veins draining into it from the pancreas. Less bleeding may occur if the vessels are ligated on both the pancreatic and the splenic vein side before they are divided. Before division of the splenic vein, its relationship to the superior mesenteric vein should be confirmed, and the inferior mesenteric vein should be ligated (Figure 5). The mobilization of the splenic vein may be enhanced by dividing it near where it joins the superior mesenteric vein (Figure 6). However, before the splenic vein is divided, the renal vein should be completely prepared for the anastomosis, since occlusion of the splenic vein increases the pressure in the retroperitoneal collateral veins in this area. Freeing up the renal vein requires delicate dissection in order to avoid injury to venous collaterals with resultant blood loss. The left adrenal vein and the gonadal vein are usually divided and securely ligated to ensure safe and adequate mobilization of the renal vein. It is not necessary to clamp the renal artery, since there are adequate venous collaterals to decompress the kidney despite complete occlusion of the renal vein.
Following division of the splenic vein, the mesenteric end is carefully closed with a continuous 00000 arterial suture (Figure 7). The coronary vein is sometimes readily visualized at this point and may be divided and ligated just above its junction with the portal vein.
One of the major problems in this procedure is the proper placement of the anastomosis between the splenic and left renal veins. The mobility of the splenic vein may need to be increased if it does not easily reach the renal vein at the proposed site of anastomosis. A wide anastomosis is essential, without twisting or angulation of the splenic vein. Following application of an occluding vascular clamp, an oblique window is excised from the wall of the renal vein, unless its size is especially small. The end of the splenic vein is tailored obliquely to fit the opening in the renal vein. It may be wise to split the end of the splenic vein for a centimeter or more to avoid tension on the anastomosis.
The splenic vein may be anchored to the renal vein at either angle, and the posterior anastomosis is completed with a continuous 00000 arterial suture (Figure 8). Interrupted 00000 arterial sutures are used in the anterior closure to minimize the splitlike character of the orifice and allow increased distensibility of the anastomosis (Figure 9). The noncrushing vascular clamp on the splenic vein is released just before the final anterior suture is tied to remove air and flush out any blood clots. A suture is taken around the coronary vein above the lesser curvature if it has not been ligated from below. This suture may include the left gastric artery, but it should be far enough away from the stomach to avoid accidental inclusion of the vagus nerves.
Venous pressures are taken in the splenic, renal, and superior mesenteric veins. Early elevations in pressure are common but do not indicate occlusion of the anastomosis provided that the splenic vein feels soft to compression and palpation reveals a thrill within the renal vein. The field of operation is rechecked carefully for evidence of uncontrolled oozing or active bleeding. The completed venous drainage outlet is illustrated in Figure 10.
Because of the possibility of ascites, a watertight closure of the peritoneum and general wound closure without drainage are indicated. Retention sutures are frequently employed. These should not penetrate the peritoneal cavity because of the danger of leakage from ascites.
Nasogastric suction should be continued after operation. Some gastric bleeding can be anticipated during the early postoperative period. Fluids during operation as well as in the early postoperative period should be restricted, with regulation based on hourly urinary output determinations and central venous pressure measurements. Diuretic therapy may be indicated to ensure a good urinary output. Ascites is a more likely development following this procedure than following other types of portosystemic decompression.