Atlas of General Surgical Techniques (Courtney M. Townsend Jr., B. Mark Evers)

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STEP 2: PREOPERATIVE CONSIDERATIONS

As with all major abdominal surgery, one needs to consider the patient’s American Society of Anesthesiologists (ASA) status and relative risk of operation. Specific to this operation are a number of features. First, because the density of beta cells may be far greater in the tail of the pancreas than in the body and the head, there is a heightened risk of insulin dependence after distal pancreatectomy. Surprising to some, the risk of insulin dependency is greater after distal pancreatectomy than it is after a resection of the head of the pancreas. It is important to advise the patient of this risk preoperatively. If the patient has an associated diagnosis of chronic pancreatitis or borderline diabetes, certainly the risk of developing insulin dependence is higher.

The second issue is the possibility of a splenectomy and the need to address the issue of postsplenectomy sepsis. This entity is now relatively easily managed by obtaining vaccines for the encapsulated organisms that are responsible for postsplenectomy sepsis. These are pneumococcus, meningococcus, and Haemophilus influenzae. There are two choices for administering these vaccines. The first is to administer them a minimum of 2 weeks before the operative procedure. The strategy is that the immune status will be sufficient to mount an antibody response to the antigens before surgery. If the decision to administer vaccines is delayed until it is clear that the patient has had a splenectomy, then the vaccines may need to be administered postoperatively. Because of the proven changes in immune capabilities early after major surgery, the recommendation is to wait a minimum of 4 weeks after surgery to administer the vaccines. These vaccines should be administered at 5-year intervals for life, and the patient should be advised of this issue before surgery. It is well known that a patient with a splenectomy may also develop thrombocytosis after surgery, and this should be monitored carefully.

Finally, particularly in patients with a normal pancreas, there is a chance that postoperative pancreatitis may develop, and enzymes should be followed for evidence of acute inflammation in the early postoperative period. It is possible to assume some of these changes are simply related to the stress of operation. One must exercise a high level of suspicion in this regard.

Perhaps the most nettlesome postoperative issue in these patients is the frequency of pancreatic fistula after resection of the tail of the pancreas. There are those who have suggested routinely using preoperatively placed pancreatic ductal stents to prevent this. This is certainly not practiced widely. In any event, it is important to advise patients that this eventuality is seen in as many as 25% of patients who have undergone resection of the tail of the pancreas. This compares poorly with the 15% risk of pancreatic fistula after pancreaticoduodenectomy.

STEP 3: OPERATIVE STEPS

Preoperative bowel prep and intravenous antibiotics at the time of the incision are both recommended. The characteristic bowel preparation is bowel cleansing combined with oral neomycin and erythromycin for three doses before the surgery. Intravenous antibiotics are generally second-generation cephalosporins or something similar.

1. INCISION

We use the left subcostal incision with a horizontal shaping of the subcostal incision at the midline to facilitate extending to the right subcostal if necessary. We similarly create a horizontal direction to the incision as we pass beneath the costal margin laterally, again to facilitate extending an incision if necessary. In general, with the exception of markedly obese patients, one can perform this operation safely with the relatively minimal incision in the left subcostal region (Figure 47-2).

Subcostal incision

FIGURE 47–2

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2. DISSECTION

Upon entering the abdomen, the general evaluation of the abdomen may be necessary, particularly if malignancy is being treated. Specifically, one should look for evidence of peritoneal seeding or any evidence of hepatic metastasis. It is also usually possible to palpate the lesion whether benign or malignant through the omentum in the left upper quadrant.

The lesser sac is entered by grasping the gastrocolic omentum and reflecting superiorly and anteriorly. This reveals the posterior surface of the omentum as it attaches to the transverse mesocolon. Using electrocautery and beginning well to the left of the spine, it is possible to dissect the attachments between the omentum and the transverse colon. There is characteristically some amount of adhesion between the appendices epiploicae and the transverse mesocolon, and these must be carefully separated until the lesser sect can be entered (Figure 47-3). At times in patients who have had previous significant pancreatitis, this plane may be impossible to traverse. As the omentum is mobilized along the transverse colon, the necessary window into the lesser sac will depend on the size of the patient and the size of the lesion. It is certainly possible to extend the dissection well over to the right of the midline if necessary to establish a wider entry into the lesser sac. Upon entering the lesser sac in this fashion, it is possible to reflect the stomach superiorly and anteriorly, revealing the anterior surface of the body of the pancreas. The omentum dissection can be carried to the left, mobilizing the splenic flexure of the colon in this fashion. It may be helpful to reflect the splenic flexure of the colon inferiorly to delineate the inferior border of the spleen and the inferior border of the tail of the pancreas. After this amount of dissection, it is hoped that one should have fully visualized the lesion and determined exactly what amount of body of the pancreas may need to be removed for adequate excision. If it is not possible to fully identify the lesion at this point, it may be necessary to use an ultrasound probe to facilitate identification. This is commonly needed when exploring for benign neuroendocrine tumors, such as insulinoma or gastrinoma (see Figure 47-3).

At this point, an option is available for defining and dissecting the splenic artery on the superior border of the pancreas. This maneuver may facilitate control of hemorrhage if one anticipates encountering significant hemorrhage during the dissection of the spleen and the tail of the pancreas. This can simply be done with an atraumatic vascular clamp if one is not certain that the spleen will need to be removed and serves as a control for hemorrhage (see Figure 47-3).

Next, attention is directed to the left hemidiaphragm in the left upper quadrant of the abdomen. The peritoneal attachments, lateral to the spleen, are incised using electrocautery, and this permits beginning of the mobilization of the spleen and the tail of the pancreas toward the midline. One may continue medially along the superior border of the spleen. As one turns the dissection in an inferior direction on the medial (hilar) aspect of the spleen, one encounters the short gastric vessels (Figure 47-4).

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At this point, one should have separated the tail of the pancreas from the splenic artery and vein or should have divided the splenic artery and vein, and the only remaining attachments should be the parenchyma of the pancreas. We prefer a fish mouth opening to the body of the pancreas. This involves angling at approximately 45 degrees toward the head of the pancreas, along the anterior border of the body of the pancreas to approximately half the depth of the body of the pancreas. We then go to 90 degrees in the opposite direction, again with a 45-degree angulation, and incise toward the tail of the pancreas. This permits apposing the ends of the divided pancreas in the hopes of preventing a pancreatic fistula (Figure 47-8).

At this point, one must carefully identify the pancreatic duct. This may be accomplished by gently massaging the body of the pancreas and expressing pancreatic juice through the pancreatic duct. In certain patients, particularly patients with a normal pancreas, the pancreatic duct can be quite miniscule. The duct is ligated with a 4-0 Prolene stitch (Figure 47-9).

Stomach

Splenic artery and vein ligated

Pancreatic duct ligated

Electrocautery of pancreas

Transverse colon

Superior mesenteric artery and vein

FIGURE 47–8

Aorta

Pancreatic duct ligated

Superior mesenteric artery and vein

FIGURE 47–9

Splenic artery

Splenic vein

Sutured closure of pancreatic remnant

Inferior mesenteric vein

Pancreaticoduodenal artery

Superior mesenteric artery and vein

FIGURE 47–12

Splenic artery

Splenic vein

Spleen in situ

FIGURE 47–13