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202 Atlas of Gastrointestinal Surgery: Shunts
A large bore needle is passed into the most anterior portion of the prosthesis, and the clamps removed slowly from the superior mesenteric vein
(15). The clamp on the inferior vena cava is left in place. This allows
the prosthesis to fill with blood, with the needle acting as a vent for
the release of air.
Pancreas
15
16
Once the prosthesis has completely
filled with blood, the clamp is removed
from the inferior vena cava, and flow
Duodenum
Inferior
vena
cava
Superior
mesenteric v.
“C” graft
through the prosthesis established. The
course of the prosthesis assumes a “C” config-
uration (16).
Interposition Mesocaval Shunt 203
The anastomosis between the prosthesis and inferior vena
Lateral view
Superior
mesenteric v.
“C” graft
17
cava is actually partially underneath the third portion of the duodenum (17). The prosthesis has to pass inferiorly as well as anteriorly to pass below the third portion of the duodenum. It then
Pancreas
Duodenum
passes on top of the third portion of the duodenum, on top of
Inferior vena cava
the uncinate process of the pancreas, to be anastomosed obliquely to the anterior surface of the superior mesenteric vein. This “C”
configuration allows the prosthesis to be anastomosed to the anterior aspect of the superior mesenteric vein, well above
where the superior mesenteric vein branching occurs. Thus, one is always assured of superior mesenteric vein with a large
diameter. Furthermore, since the anastomosis is oblique, it tends to be very large. In addition, since the anastomosis is to
the anterior aspect of the superior mesenteric vein, it is technically easy to perform. This is in contrast to the old mesocaval “H” shunt, which runs directly anteriorly from the inferior vena cava, below the lower border of the third portion of the
duodenum, and joins the posterior aspect of the superior mesenteric vein. The “H” shunt anastomosis is harder to perform
and is often performed to a segment of the superior mesenteric vein that is already branched.
Mesenteric venous pressure can be measured post-shunt, by inserting a 19-gauge needle, connected to a manometer,
into the prosthesis. Pressures can be measured with the prosthesis toward the vena cava clamped and unclamped.
Distal Splenorenal Shunt
Operative Indications:
The distal splenorenal shunt is a selective shunt, in contrast to the mesocaval and portacaval shunts, which are total shunts.
The distal splenorenal shunt is constructed so that mesenteric blood continues to flow antegrade into the liver, while gastroesophageal varices are decompressed retrograde through the vasa brevia and left gastroepiploic vessels into the spleen, and
out the splenic vein into the systemic venous system. This shunt was introduced in an attempt to eliminate the portasystemic
encephalopathy that some patients develop after a total shunt. With the acceptance of sclerotherapy and variceal banding
as the first line of management for gastroesophageal variceal bleeding secondary to portal hypertension, the need for elective
portasystemic decompression has decreased. The introduction and increased usage of the transjugular intrahepatic portasystemic shunt (TIPS) procedure has also further decreased the need for operative portasystemic decompression procedures.
Even though the TIPS procedure has been used principally for the short-term control of bleeding varices and as a bridge to
liver transplantation, in some instances, patency has been such that it has proven to be a longer term solution.
Nevertheless, there are situations in which an elective portasystemic shunt is indicated. Many surgeons have accepted the
selective distal splenorenal shunt as the procedure of choice in the elective situation. Patients with intractable ascites are not
candidates for the distal splenorenal shunt. Since sinusoidal pressure is not decreased by the distal splenorenal shunt, massive
ascites is not treated effectively by this procedure. Technically, the distal splenorenal shunt is a difficult operative procedure and
should not be attempted in the emergency setting. But patients with liver disease, portal hypertension, and a history of bleeding esophageal varices, but still with good liver reserve and who are considered candidates for an elective shunt, are good candidates for the distal splenorenal shunt. Many patients with severe liver disease and no liver reserve, who in the past were considered candidates for the distal splenorenal shunt, are now considered candidates for liver transplantation.
Distal Splenorenal Shunt 205
Candidates for the distal splenorenal shunt should be worked up angiographically prior to surgery. Celiac axis and supe-
rior mesenteric angiography will demonstrate on the venous phase whether or not there continues to be prograde mesenteric flow to the liver. If there is no prograde flow, the potential theoretical benefits of the distal splenorenal shunt are obviated, and the patient should be considered for a total shunt. If, however, prograde flow to the liver is demonstrated and
the mesenteric venous system is patent, the patient is an appropriate candidate for a selective shunt. The position of the
left renal vein should also be determined angiographically, so that its relationship to the splenic vein is delineated prior to
surgery. These same vascular structures, and their relationships to each other, can also be demonstrated by a thin section,
three-dimensional CT scan or MRI angiography. The direction of flow, however, cannot be determined. If the distal
splenorenal shunt is performed correctly, one can expect a high incidence of shunt patency, excellent control of bleeding
from gastroesophageal varices, and perhaps a reduction of both the incidence and severity of portasystemic encephalopathy when compared to a total shunt.
Operative Technique:
Either a long upper midline incision or a long left subcostal incision with extension across the
right rectus muscle can be used for the operative procedure. After the peritoneal cavity is
opened, the abdomen is explored for evidence of additional pathology. If none is found, a
liver biopsy is obtained if one has not been performed preoperatively. Upon entering the
abdomen, great care should be taken to divide all vascular attachments to the spleen, so that
the splenic capsule is not torn. Obviously, preservation of the spleen is essential in this operative procedure, and care should be taken immediately upon entering the abdomen to be cer-
tain that the spleen is not injured. The lesser sack is entered by dividing the gastrocolic omentum along the greater curvature while preserving the gastroepiploic blood supply to the stomach. The right gastroepiploic
vein is divided at the level of the pylorus, but the artery is preserved. Care should be taken to preserve the left gastroepiploic vein, with its gastric branches draining toward the splenic hilum. While expanding the opening in the lesser sac toward
the spleen, one has to be certain not to divide any of the vasa brevia.
206 Atlas of Gastrointestinal Surgery: Shunts
The retroperitoneum is entered along the
inferior border of the pancreas (1). This
border is usually visible and can be
identified quickly by palpation. The
plane in the retroperitoneum
along the inferior border of the
pancreas is often relatively
bloodless, even in the cirrhotic. Large lymphatic
channels, however, are
often encountered and
should be controlled
by clamping, division, and ligation to
prevent the subsequent accumulation
of ascites.
Stomach
1
Pancreas
R. gastroepiploic v.
divided
2
Transverse
colon
Retroperitoneum
Pancreas
Splenic v.
Once this space along the inferior border of the pancreas is
opened, the pancreas is mobilized out of the retroperitoneum. The
first structure often encountered is the inferior mesenteric vein. This
Divided inferior
mesenteric v.
vessel is an excellent guide to the splenic vein and, if it enters the
splenic vein, should be ligated and divided at that junction (2).
The inferior border of the pancreas is reflected cephalad, and the splenic vein
Distal Splenorenal Shunt 207
Ligated
coronary v.
is identified and cleaned on its posterior surface. The splenic vein usu-
Portal v.
Splenic v.
ally transverses the pancreas posteriorly approximately at its midportion, but may on occasion be closer to its superior border.
Once the splenic vein is identified, it is carefully mobilized cir-
3
cumferentially for a 6 or 7 cm distance from its junction with
the superior mesenteric vein out towards the tail of the pan-
Pancreas
creas (3). This requires meticulous, slow, and fastidious dissection. After its posterior and inferior surfaces are cleaned of all sur-
Superior
mesenteric v.
rounding areolar tissue, its anterior surface is visualized, carefully identifying the small branches passing anteriorly into the posterior aspect of the pancreas. These small branches should be doubly ligated in continuity, prior to division. Some have suggested ligating the
splenic vein side of the branches and using small ligaclips on the pancreas side. In our experience, the small ligaclips often
are displaced on the pancreatic side, and further hemostasis is required. With careful, fastidious dissection, the splenic vein
can be completely mobilized from the posterior aspect of the pancreas. This dissection is particularly difficult in the patient
with chronic pancreatitis, but it is always possible. The junction of the splenic vein with the superior mesenteric vein should
be identified early since a vessel loop passed around the splenic vein at this point facilitates the dissection. The dissection
should also proceed further along the superior aspect of the portal vein in an effort to identify the coronary vein. If found
in this location, the coronary vein is doubly ligated and divided.
Once an adequate length of splenic vein has been mobilized circumferentially, the left renal vein is identified and dissect-
ed. In obese patients, this may be difficult, and localization of the left renal vein is facilitated by elevating the transverse
mesocolon, dividing the ligament of Treitz, and exposing the vein as it crosses the aorta,
as is done in aortic surgery. Use of intraoperative ultrasound may also be of
Ligated
Portal v.
coronary v.
Splenic v.
value. On deepening the dissection in the retroperitoneum towards
the left renal vein, enlarged lymphatic channels are once again
encountered, and they should be clamped and ligated to
decrease subsequent ascites formation. The left renal vein is
Pancreas
Superior
mesenteric v.
Gonadal v.
4
Adrenal v.
Renal v.
identified and cleaned for a length of approximately 6 cm
(4). The gonadal and left adrenal veins are easily identified.
They should both be ligated and divided (4). Care has to
be taken in dissecting and encircling these two veins with a
right-angle clamp, because additional branches often join
these venous structures posteriorly close to their junction with
the renal vein.
208 Atlas of Gastrointestinal Surgery: Shunts
Once an adequate length of left renal vein is mobilized, the splenic vein
is divided close to its junction with the superior mesenteric vein
(5). The splenic vein is clamped just before its junction with
the superior mesenteric vein with two straight Cooley
clamps. The vein is then divided, and the end of the
splenic vein adjacent to the superior mesenteric vein is
oversewn with a continuous 5-0 synthetic nonabsorbable suture. In the past, this vein end was merely ligated, if length permitted. This option left a small
cul-de-sac which, in a large diameter, low-flow, venous
system, resulted in thrombosis that on occasion extended up into the portal vein. Thus, one should oversew the
splenic vein end at its junction with the superior mesenteric vein
as close as possible in order to avoid leaving a cul-de-sac behind.
Before dividing the splenic vein, it is helpful to mark its superior and inferior bor-
5
Splenic v.
Portal v.
Superior
mesenteric v.
ders with fine traction sutures, so that orientation is maintained during the subsequent performance of the splenorenal anastomosis. In determining the length of the splenic vein, one needs to perform a tension-free anastomosis. One should be certain
to release the retraction on the inferior border of the pancreas. If one continues to retract the pancreas cephalad, this can result
in a segment of the splenic vein that proves too long once the anastomosis has been completed, and the pancreas is allowed
to return to it normal position.
A 1.5 to 2 cm long, but narrow, ellipse of renal vein is removed along its superior border (5). This ellipse occasionally
includes the ligated stump of the adrenal vein. Prior to performing the anastomosis, the splenic vein is occluded toward its
splenic end with a DeBakey bulldog clamp, and the straight Cooley
Splenic v.
oversewn
clamp is removed. The renal vein, which has been mobilized
circumferentially, is occluded proximally and distally with
Portal v.
6
straight Cooley clamps. The posterior layer of the
splenorenal anastomosis is performed first, with a con-
tinuous 5-0 synthetic non-absorbable suture (6). The
suture line is placed from within the vessels.
Pancreas
Splenic v.
Renal v.
Superior
mesenteric v.
Although the anterior suture line can also be placed in a continuous fashion,
Distal Splenorenal Shunt 209
we usually place a series of interrupted 5-0 synthetic non-absorbable sutures
7
to avoid purse stringing (7). Before the final suture is secured in the anterior row of the anastomosis, the DeBakey bulldog clamp is removed from
the splenic vein, with the Cooley clamps still in place on the renal vein,
to fill the anastomosis with blood and to evacuate air. The Cooley
Splenic v.
clamps are then removed from the renal vein.
Renal v.
A modification of the distal splenorenal shunt can be performed whereby the body and tail of the
pancreas are completely mobilized off the splenic vein all the way to the splenic hilum. This modification was introduced in an attempt to prevent the development of vascular collaterals between the mesenteric venous system providing
prograde flow to the liver and venous channels leading to the spleen that are decompressed through the distal splenorenal
shunt. The development of such collaterals through
the pancreas can obviate the selectiveness of
Entire length
of splenic v.
8
Spleen
this shunt and result in mesenteric blood
entering the systemic venous system
and bypassing the liver. In performing
this modification, the mobilization
and cleaning of the splenic vein cir-
cumferentially proceeds towards
the splenic hilum until the body
and tail of the pancreas are actu-
ally completely free all the way
to the hilum (8). This prolongs
the procedure, but is felt by
Pancreas
Ligated inferior
mesenteric v.
Renal v.
some to be necessary to
ensure long-term success of
the distal splenorenal shunt.
210 Atlas of Gastrointestinal Surgery: Shunts
When one successfully constructs a selective distal splenorenal shunt, portal hypertension persists in the mesenteric system, and prograde flow continues through the portal vein and into the liver. In contrast, the pressure in the gastroesophageal
varices has been lowered by decompression through the vasa brevia and left gastroepiploic vessels into the spleen, out the
splenic vein, and into the left renal vein. These two
portal beds are further disconnected by ligating the
9
Paraesophageal vv.
Vasa brevia
right gastroepiploic, the coronary, and the right and
Spleen
left gastric veins (9). If the coronary vein has not
been ligated at its junction with the portal vein, it
should be interrupted at the superior border of
the pancreas. The umbilical vein is also ligated at the point where the abdominal
incision crosses the ligamentum teres.
Portal v.
Pancreas
Divided r.
gastroepiploic v.
Inferior
Inferior
vena cava
vena cava
Coronary v.
L. gastroepiploic v.
Splenic v.
Renal v.
Superior
mesenteric v.
Kidney
Portacaval Shunt
Operative Indications:
Today, most patients with liver disease, portal hypertension, and bleeding esophageal varices are managed nonoperatively
with sclerotherapy or variceal banding. Others, with advanced liver disease and no hepatic reserve, are managed by liver
transplantation. In addition, the introduction of TIPS has eliminated the need for emergent surgical intervention in those
patients whose bleeding esophageal varices cannot be controlled by sclerotherapy or banding. Even though long-term
patency of the TIPS procedure remains a problem, many patients are being managed utilizing TIPS for intermediate or even
long-term control of the portal hypertension. There remains, however, a small group of patients with portal hypertension
and bleeding varices that cannot be controlled long-term with sclerotherapy or banding, but who have enough hepatic
reserve and synthetic function that they are not yet candidates for liver transplantation. These patients are candidates for a
mesenteric systemic venous shunt. In addition, the rare form of portal hypertension, Budd-Chiari syndrome, is still considered an indication in some instances for mesenteric systemic venous shunting.
Which shunt to use when mesenteric systemic venous shunting is indicated remains controversial, despite decades of
data collection and debate. The first shunts to be used successfully were the end-to-side and side-to-side portacaval anastomoses. Although used infrequently today, these shunts still have their advocates. The end-to-side portacaval shunt can
be performed with moderate speed and only moderate blood loss. This shunt is contraindicated in patients with intractable
ascites, since sinusoidal pressure is not reduced with this procedure. However in an occasional patient with no ascites, and
who angiographically has been demonstrated as having retrograde flow out the portal vein, this shunt has some theoretical
advantage. The incidence of encephalopathy following an end-to-side portacaval shunt is significant, but its incidence compared to the side-to-side portacaval shunt is probably less. Even though all prograde flow to the liver through the portal
venous system is obviously interrupted following an end-to-side shunt, retrograde flow out the portal vein does not occur.
Many feel that end-to-side portacaval shunting carries with it a lower incidence of encephalopathy than the side-to-side
shunt, and it has a clear theoretical advantage in the patient who preoperatively already has retrograde flow.
The side-to-side portacaval shunt can be used in the presence of intractable ascites. Mesenteric pressure is not only
reduced, but the portal vein is converted into an outflow tract, and sinusoidal pressure is lowered, thus effectively elimi-