Fig. 8.1
The aorta and inferior vena cava are exposed behind the intestinal mesentery
2.
The ligament of Treitz is broadly mobilized from the retroperitoneum and aorta, mobilizing the distal duodenum and proximal jejunum. The abdominal aorta is encircled distally for eventual aortic cannulation and flush. The gastrocolic omentum is divided, and the left colon is mobilized (red arrow) (Fig. 8.2). The mesentery of the colon is then dissected, exposing right, middle, and left colic vessels. Exposure of the colic vessels (blue arrow) facilitates rapid removal of the colon immediately prior to heparinization and cannulation. If the right colon is to be a component of the graft, care must be taken to not disturb the right and transverse colon mesentery. This mesentery must be left intact in order to prevent internal herniation through the mesenteric defect in the recipient.
Fig. 8.2
The gastrocolic omentum is divided, and the left colon is mobilized (red arrow). The mesentery of the colon is then dissected, exposing right, middle, and left colic vessels (blue arrow)
3.
A medial visceral rotation mobilizes the tail of the pancreas (yellow arrow) with the spleen (blue arrow), exposing the left side of the aorta and origin of the mesenteric vessels (Fig. 8.3). As with standard pancreas procurement, the pylorus is transected with a linear stapler, leaving sufficient length to invert the staple line with another layer of suture. The stomach is rotated laterally out of the abdominal field after ligation of the left gastric artery, separation of the stomach from the greater omentum, and division of the short gastric vessels to the spleen. The use of the inferior mesenteric vein (IMV) for flush during intestinal procurement is discouraged, as high flow and pressure in the IMV flush may decrease intestinal outflow through the superior mesenteric vein. In multivisceral graft procurement, care must be taken to avoid injury to the left gastric artery, while attachments of the stomach to the colon via the greater omentum are still divided.
Fig. 8.3
A medial visceral rotation mobilizes the tail of the pancreas (yellow arrow) with the spleen (blue arrow), exposing the left side of the aorta and origin of the mesenteric vessels
4.
The liver graft dissection is performed in the standard manner, described elsewhere in this atlas. Once there is satisfactory dissection by all participating procurement teams (heart, lung, liver, pancreas), and prior to administration of systemic anticoagulants, the small intestine luminal contents are manually propulsed in an antegrade fashion from the pylorus to the ileocecal valve. Because the bowel is a hollow viscus, air left in the organ may allow more rapid rewarming during cold preservation. Care must be taken while manually advancing luminal contents to prevent serosal injury of the sometimes fragile intestine. This maneuver decompresses the small intestine of both air and liquids and advances the luminal contents into the colon, allowing the ileocecal valve to prevent reflux. This should be the final maneuver performed prior to heparinization and aortic cannulation.
Once the small intestine is decompressed, the bowel is transected at the distal ileum and sigmoid. The colonic mesenteric vessels (blue arrow), which had been previously dissected, are ligated and transected, and the colon is rapidly removed from the cadaver (Fig. 8.4). Vascular transection of the colon should be performed last to prevent drainage from an ischemic colon into the liver.
Fig. 8.4
The bowel is transected at the distal ileum and sigmoid. The colonic mesenteric vessels (blue arrow), which had been previously dissected, are ligated and transected, and the colon is rapidly removed from the cadaver
5.
The donor cannulation, cross-clamping, flushing, thoracic venting, and topical cooling are performed in the standard manner as for other abdominal multiorgan procurements. A laparotomy pad should protect the intestine from direct exposure to ice slush, which may cause subserosal hematomas. Immediately prior to cross-clamping, the small intestine mesentery must be examined closely to ensure that there is no unintended volvulus. Doing so will ensure adequate flush to both the intestine and liver portal system.
6.
The liver is removed first, with transection of the portal vein at the level of the coronary vein, and transection of the splenic artery. As in standard pancreas procurement, the splenic artery is always tagged with a fine suture for later identification. The pancreas and intestine graft may be removed en bloc, and the pancreas separated from the intestine at the back-table dissection. This technique ensures rapid organ retrieval from the cadaver after flush and allows for identification and ligation of individual proximal jejunal and duodenal mesenteric vessels in a controlled environment. Using this technique, both the pancreas and intestinal grafts can be removed quickly from the cadaver by simply transecting the superior mesenteric artery at its aortic origin with or without a Carrel patch, as preferred by the pancreas surgeon.
7.
Division of the base of the small intestine mesentery just below the inferior pancreaticoduodenal arcade may be performed in situ in a stable donor. Failure to achieve a complete bloodless dissection in this maneuver will quickly result in a hematoma at the base of the mesentery and may compromise the intestinal graft. In this case, the middle colic vessels are divided, and the ligament of Treitz is widely mobilized from over the aorta and the inferior margin of the pancreas. The mesentery may be isolated by placing the entire small bowel over a moist laparotomy pad. The jejunum may be divided with a stapling device approximately 10 cm distal to the ligament, and the superior mesenteric vein is identified laterally in the mesentery. Fine ligation of all lymphatic structures is performed, isolating the superior mesenteric vein and artery. The artery will usually give off a proximal jejunal arcade that requires division. Additionally, care must be taken not to injure the main jejunal vein draining the proximal allograft, as this usually runs posterior to the artery, joining the ileal vein to form the superior mesenteric high in the mesentery. If the colon is to be a component of the graft, the middle colic artery and vein should be carefully preserved. Occasionally the middle colic vein joins the superior mesenteric vein above the insertion of the proximal jejunal vein tributary. In this case, sacrifice of the middle colic vein is warranted and is usually well tolerated.
The isolated intestine donor operation historically precluded the use of the pancreas from the same donor, but with close coordination between liver, pancreas, and intestinal procurement teams, successful procurement of all of these individual organs can be safely achieved (Berney et al. 2002). The notable exception is the case in which the donor has a replaced right hepatic artery arising low on the superior mesenteric artery.
8.1.2 Back-Table Procedure
1.
If the pancreas is not being transplanted, the back-table dissection begins at the level of the portal vein. Stay sutures are placed on the portal vein and the cuff of the superior mesenteric artery (Fig. 8.5)
Fig. 8.5
To begin the back-table dissection, stay sutures are placed on the portal vein and the cuff of the superior mesenteric artery
2.
The portal vein dissection begins at the level of transection. Small pancreatic venous tributaries are identified and ligated. Care should be taken to preserve the splenic vein (Fig. 8.6), as this provides a useful conduit for flush of preservation solution from the allograft at the time of reperfusion.
Fig. 8.6
Small pancreatic venous tributaries are identified and ligated. Care should be taken to preserve the splenic vein. IMV inferior mesenteric vein, SMV superior mesenteric vein
3.
During separation of the intestinal graft from the pancreas, the jejunum is first transected and the small and numerous jejunal mesenteric vessels are ligated. The finished graft should have a well-developed portal vein and superior mesenteric artery (SMA) for implantation (Figs. 8.7 and 8.8).
Fig. 8.7
The finished graft should have a well-developed portal vein and superior mesenteric artery (SMA) for implantation
Fig. 8.8
The finished graft should have a well-developed portal vein and superior mesenteric artery (SMA) for implantation
4.
To facilitate flushing of preservation solution from the graft prior to reinstitution of the graft with the systemic circulation, a small cannula may be placed in the splenic vein stump (blue arrow) for ease in flush measurement. We prefer the use of a Sundt carotid endarterectomy shunt (red arrow), which is used to allow egress of the preservation solution prior to opening the venous clamp (Fig. 8.9). The shunt is then removed, the venous outflow clamp is opened, and the splenic stump is ligated.
Fig. 8.9
A small cannula may be placed in the splenic vein stump (blue arrow) for ease in flush measurement. A Sundt carotid endarterectomy shunt (red arrow) can be used to allow egress of the preservation solution prior to opening the venous clamp
5.
If the pancreas is also to be transplanted as a whole-organ allograft, the mesentery is isolated upon a moist lap pad, and the mesenteric vessels are isolated below the inferior pancreaticoduodenal artery and vein, which provide necessary flow to the pancreas allograft. The middle colic vessels and first jejunal arcade usually must be ligated. Care should be taken not to injure the major jejunal vein, which usually courses behind the SMA to join the ileocolic vein high in the base of the small bowel mesentery. Small vascular clamps are placed on the SMA and superior mesenteric vein (SMV) after the flush, and these vessels are transected. The pancreatic side is individually oversewn with fine, nonabsorbable suture and the bowel graft is again flushed on the back table. The pancreas and liver are then removed in the usual fashion. If an aberrant right hepatic artery or aberrant common hepatic artery is encountered from the SMA, care must be taken to avoid injury to these vessels, and the SMA must be divided distal to the origin of the aberrant vessel. In this situation, good-quality iliac or common femoral artery and vein extension grafts are required for implantation of the small-bowel graft.
8.1.3 Recipient Procedure
Isolated intestinal transplantation is usually described by the technique of vascular reconstruction used for venous drainage, being either “mesenteric/portal” or “systemic.” The surgical approach is determined by the recipient’s underlying intestinal disease, the health of the recipient’s liver, and anatomic considerations that may influence the surgeon (Bueno et al. 2000). The procedure is usually accomplished through a generous midline incision, although in babies weighing less than 10 kg we sometimes prefer a transverse incision if one has previously been made.
We prefer to use mesenteric drainage for patients in whom the native small bowel is in place and will be removed at the time of transplantation. In cases of extreme short bowel, the superior mesenteric vessels carry little flow and are usually quite small. They may not accommodate sufficient blood supply for the transplanted bowel, and we usually prefer systemic vascular reconstruction for these patients.
8.1.3.1 Mesenteric Vascular Reconstruction
1.
For candidates receiving an isolated intestinal allograft for functional disorders (infantile diarrhea or motility disorder), the native small bowel is usually in place. In this instance, blood flow through the mesenteric vessels is preserved, and they are usually of adequate caliber and quality for supply to the graft. Implantation, therefore, can be performed using these vessels prepared in the same manner as for isolated intestinal graft procurement. The jejunum is divided 10–20 cm distal to the ligament of Treitz, which is broadly mobilized. The arcade to the proximal jejunum is preserved. The recipient bowel is suspended by the root of the mesentery after disconnection at the proximal jejunum and colon, enabling fine dissection of the mesenteric root (yellow arrow) and isolation of the SMA and SMV (Fig. 8.10).
Fig. 8.10
The recipient bowel is suspended by the root of the mesentery after disconnection at the proximal jejunum and colon, enabling fine dissection of the mesenteric root (yellow arrow) and isolation of the SMA and superior mesenteric vein (SMV)
2.
If the colon is intact, the middle colic vessels are ligated, the right and transverse colon is mobilized, and the left transverse or descending colon is divided. We always mobilize or remove the splenic flexure of the colon to ensure endoscopic access to the ileum from below after closure of the stoma. The superior mesenteric vein (SMV) (blue arrow) is located lateral to the SMA (yellow arrow) (Fig. 8.11). Dissection of the base of the mesentery is undertaken to skeletonize these vessels. These tissues should all be ligated to avoid lymphatic or chylous ascites after transplantation (Kato et al. 1999).
Fig. 8.11
The SMV (blue arrow) is located lateral to the SMA (yellow arrow). Dissection of the base of the mesentery is undertaken to skeletonize these vessels
3.
Small vascular clamps may be used to control the SMA and SMV, dividing them distally and preserving long cuffs for anastomosis (Fig. 8.12). The proximal native jejunum should be preserved with the proximal jejunal arcade of the SMA for anastomosis to the donor jejunum.
Fig. 8.12
Small vascular clamps may be used to control the SMA and SMV, dividing them distally and preserving long cuffs for anastomosis
4.
In some cases, placement of iliac or femoral arterial and venous conduits onto the graft vessels will be required (Fig. 8.13). We have found that this facilitates transplantation when the pancreas has been procured for transplantation, as the graft mesenteric vessels will be shorter. They are best sewn in place prior to bringing the allograft into the field for implantation. Usually, either a short portion of external iliac or superficial femoral artery and vein are of appropriate caliber for anastomosis to the superior mesenteric vessels. The weight of the small bowel allograft may lead to tension over the duodenal sweep and predispose the graft to settle inferiorly toward the pelvis, so when using mesenteric reconstruction, attention should be paid to leaving generous length on the mesenteric vessels. Again, the main SMV should be used above the confluence of the jejunal and ileal branches, which usually is quite close to the duodenal sweep.
Fig. 8.13
Placement of iliac or femoral arterial and venous conduits onto the graft vessels will be required in some cases. They are best sewn in place prior to bringing the allograft into the field for implantation
In patients with short-bowel syndrome, the SMV sometimes cannot be exposed, as the base of the mesentery contracts after multiple prior resections. The venous anastomosis may be performed to the lateral wall of the portal vein in piggyback fashion, dissecting this vein free from the posterior porta hepatis and placing an extension graft of iliac vein onto this vein in end-to-side fashion (Grant et al. 1990). We have only rarely employed this technique, and we discourage its routine use, as outcomes with systemic drainage are equivalent and are accomplished with greater ease. However, this technique may be useful in cases of inferior vena cava thrombosis, where the alternative is placement of a venous extension graft on the suprarenal inferior vena cava, discussed below.
5.
The bowel is then brought to the field after extension grafts are placed on the recipient vessels, and the base of the mesentery is placed in a transverse plane aligning the donor and recipient vessels. The assistant is best positioned with a cold moist lap pad to flatten the base of the mesentery and prevent bowel loops from entering the field, giving upward traction on the bowel allograft during anastomosis. The vessels are anastomosed end to end (Fig. 8.14).
Fig. 8.14
The donor and recipient vessels are anastomosed end to end
6.
Reperfusion is then accomplished without heparinization. Upon reperfusion, blood and preservation solution is flushed out (blue arrow) prior to removal of the SMV clamp (Fig. 8.15). This is facilitated by the previously placed cannula in the graft splenic vein, or through the SMV anastomosis.
Fig. 8.15
Upon reperfusion, blood and preservation solution is flushed out (blue arrow) prior to removal of the SMV clamp
7.
The SMV clamp is then removed and venous return is reestablished (blue arrow) (Fig. 8.16).
Fig. 8.16
The SMV clamp is then removed and venous return is reestablished (blue arrow)
8.
It is critical to fix the base of the mesentery transversely and without kinking of the vessels, to avoid volvulus or traction on the mesenteric vessels (Fig. 8.17).
Fig. 8.17
It is critical to fix the base of the mesentery transversely and without kinking of the vessels, to avoid volvulus or traction on the mesenteric vessels
8.1.3.2 Systemic Vascular Reconstruction
This technique is more commonly employed for patients with short-bowel syndrome, particularly those with total or near-total loss of jejunum and ileum. In this disease state, the mesenteric vessels are often small in caliber, lacking good inflow. This is not always the case, however; when a smaller donor with commensurately small vessels is being used, mesenteric drainage may still be employed.
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1.
The recipient operation requires exposure of the infrarenal aorta for anastomosis of the arterial graft (Fig. 8.18). The limits of dissection include the left renal vein above and the inferior mesenteric artery below.
Fig. 8.18
The recipient operation requires exposure of the infrarenal aorta for anastomosis of the arterial graft
2.
The inferior vena cava and aorta are clamped in preparation for systemic vascular anastomosis (Fig. 8.19). The dissection may proceed below the inferior mesenteric artery, and this vessel controlled with a fine clip during anastomosis.
Fig. 8.19
The inferior vena cava and aorta are clamped
3.
The arterial graft must be performed in a tension-free manner, as the weight of the bowel filled with secretions can lead to traction from the aorta to the pelvis or lead to decreased flow and thrombosis. The venous anastomosis is end-to-side to the anterior wall of the vena cava, as with a portocaval shunt (Fig. 8.20). This is best accomplished after removal of an ellipse of vena cava to avoid narrowing, as is common in the creation of mesocaval shunts. We prefer aortic inflow and caval drainage for patients who have demonstrated significant liver cholestasis, fibrosis, or ultrashort-bowel syndrome (Fishbein et al. 2000a). It is easy to accomplish, and in cases where intestinal transplantation is indicated because of reversible, progressive liver disease, it avoids drainage of the bowel graft into the possibly high-pressure portal circulation. The bowel graft is again oriented with the transverse mesentery parallel to the plane of the retroperitoneum and is sewn either directly to the aorta and vena cava or (as is our preference) to short extension grafts already placed to these vessels. Prior placement of extension grafts routinely makes implantation easy, preventing loops of allograft small intestine from obscuring the field of anastomosis. The mesentery is then fixed to the retroperitoneum to avoid internal hernia, volvulus, or traction on the vessels, care being taken to avoid the ureters. Systemic drainage has not been shown to yield inferior nutritional results, as some had initially predicted (Berney et al. 2002; Shaffer et al. 1988; Reyes et al. 2002).
