Courtesy of J. Michael Henderson, M.D., F.A.C.S., The Cleveland Clinic
Foundation, Cleveland, Ohio
Rationale
Distal Splenorenal shunt provides selective variceal decompression to control bleeding gastroesophageal varices, while maintaining portal
hypertension and prograde portal flow to the liver (Figure 1).
Thrombosis of distal splenorenal shunts occur in less than 10% of patients, but usually occurs early (in the first
week) and require reoperation. Intraoperative measurement of shunt flow can probably reduce the risk of this complication.
Surgical Approach
On completion of the distal splenorenal shunt anastomosis, 2-3 cm of the splenic vein is free below the pancreas before it is anastomosed to
the left renal vein. A Transonic flowprobe (8 - 12 mm) can be placed on this segment of the splenic vein for volumetric flow measurement (Fig. 2). A probe is chosen to fit
comfortably around the vein without compressing it: it should lie in line with the vessel, and no tissue should be interposed. Contact is assured by immersing the field in
saline. Flow measurements stabilize within one minute, and fluctuate less than ± 10%.
Box indicates site of flowprobe application.
Discussion
What
should the flow be in a distal splenorenal shunt? This is a high flow shunt, with volumetric flows determined largely by spleen size. There appears to be approximately 1 ml/min flow per cubic centimeter spleen volumes - i.e. a 750 cc spleen will give a shunt volumetric flow of approximately 750 ml/min. On initially removing the clamps, flow tends to be higher than the flow after 5-10 minutes when the initial hyperemia has resolved. If flow is significantly less than this approximation, a technical error should be looked for. Is the splenic vein kinked? Is there a problem with the anastomosis? Now is the time to identify and correct a technical problem: transit-time ultrasound flowprobes offer a method for identifying low flow in this shunt.
