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Surgery of the Pancreas

Cancer of the pancreas is the most common indication for surgery of the pancreas. It is the fourth leading cause of cancer death in men and fifth in women. Surgery provides the best chance for survival but under the very best circumstances there is only a 20% chance of a five year survival. It is demanding surgery with many potential complications. Cigarette smoking is considered a significant risk factor for pancreatic cancer.

Anatomy

  • The pancreas lies across the upper abdomen. It extends from the inside of the C loop of the duodenum (Surgery of the Duodenum) to the hilum of the spleen (Splenectomy). It lies behind the stomach and the peritoneum (the thin lining of the abdominal cavity). The head of the pancreas lies in the C- shaped duodenal curve while the tail of the pancreas lies toward the spleen. The body of the pancreas lies between the head and the tail. (Figure 1)
Figure 1 - Anatomy of the pancreas and surrounding structures. © C. McKee
  • The blood supply comes from branches of the celiac, superior mesenteric and splenic artery
  • Blood drains by veins to the large portal vein that drains into the liver
  • The lymph nodes that come from the pancreas are plentiful and follow the major arteries and veins
  • The pancreas has both exocrine (having ducts) and endocrine (without ducts) histology (tissue as seen under the microscope)
    1. The exocrine portion is analogous to a cluster of grapes with the grapes representing the secreting unit that produces the pancreatic digestive enzymes. The grape stems would be the pancreatic ducts coming together to form a single large duct (duct of Wirsung) that empties into the duodenum at a small raised area, the ampulla of Vater
    2. The endocrine portion, called the islets of Langerhans, are scattered throughout the pancreas. The various cells that make up the islets of Langerhans produce numerous hormones

Physiology

  • The exocrine portion of the pancreas secretes many enzymes that are delivered into the duodenum through the pancreatic duct to help digest food. Stimulation of the vagus nerve causes the pancreas to secrete these enzymes. Some of these digestive enzymes are:
    1. Amylase - breaks down starch
    2. Lipase - breaks down fat
    3. Trypsin, chymotrypsin and kallikrein - break down various proteins
  • Multiple endocrine hormones are produced by different cells within the islets of Langerhans
    1. Insulin produced by the beta cells of the islands is necessary for controlling the level of sugar (glucose) - elevated glucose levels cause increased secretion of insulin and low levels of glucose cause a decrease
    2. Glucagon from the alpha cells is secreted in response to low blood glucose and causes the breakdown of glycogen (a starch) into glucose
    3. Somatostatin from the delta cells inhibits pancreatic endocrine (hormone) secretion and exocrine secretion
    4. Pancreatic polypeptide from non-beta cells decreases the exocrine function of the pancreas

Pathology

  • Anatomical abnormalities of the pancreas:
    1. Annular pancreas - pancreatic tissue during development encircles the duodenum causing obstruction (Figure 2A)
    2. Accessory pancreas - pancreatic tissue that is found in other organs such as the stomach, small bowel and gall bladder (Figure 2B)
Figure 2a - Annular pancreas surrounding the duodenum. © C. McKeeFigure 2b - Example of accessory pancreatic tissue. © C. McKee
  • Inflammation of the pancreas is divided into acute and chronic pancreatitis
    1. Acute pancreatitis presents fairly rapidly with varying degrees of inflammation:
    • Mild - mild swelling of the pancreas that is a short lived process and results in a full recovery
    • Moderate - there is more inflammation that requires hospitalization, careful replacement of body fluid that may be lost and there is usually no permanent damage
    • Severe - the inflammation progresses to tissue death, shock, infection, failure of many organs and high mortality
    1. Chronic pancreatitis is usually due to repeated episodes of acute pancreatitis. The inflammation ultimately causes strictures (narrowings) in the ducts resulting in various degrees of obstruction
  • The majority of pancreatitis (90%) is caused by biliary (bile) tract disease, such as obstructing or migrating stones in bile ducts, or alcohol. Other causes are idiopathic (of unknown origin), elevated lipids (fat) or calcium, trauma, ischemia (inadequate blood supply), viral, drugs and following surgery of the biliary or pancreatic ducts. Severe pancreatitis may result in the breakdown of the pancreatic ducts with formation of:
    1. Pseudocyst (false cyst) - ductal rupture allows pancreatic secretions to collect outside the pancreas within a fibrous capsule
    2. Fistula - following pancreatic duct rupture secretions may drain to the outside of the body (external fistula), erode into another intestinal structure (internal fistula) or drain into the peritoneal cavity (pancreatic ascities)
  • Malignant (cancerous) exocrine tumors of the exocrine duct system arise from ductal epithelium:
    1. Duct cell adenocarcinoma - 90% of exocrine malignancies are found most often in the head of the pancreas (Figure 3)
    2. Cystadenocarcinoma - a less aggressive tumor that is associated with cyst formation
    3. Acinar cell carcinoma - arises from secretory cells of the exocrine system
    4. Periampullary adenocarcinoma - arise in the ampulla of Vater area. It may be duodenal, ampullary or common bile duct in origin and is difficult to differentiate from the pancreas. Eighty five percent of pancreatic tumors with jaundice presentations will be due to this tumor
    5. Solid and Papillary Neoplasms - low grade large malignant tumors usually in young women with a questionable cell of origin
    6. Lymphoma of pancreas - this is a rare tumor and not a surgical disease
Figure 3 - Tumor of the head of the pancreas overlying the junction of the pancreatic and bile ducts. © C. McKee
  • Cystadenomas are benign tumors of the exocrine pancreas and may be serous or mucinous. Serous tumors have a watery secretion. Mucinous tumors have a mucus like secretion and a potential to become cancerous
  • Endocrine tumors of the pancreas are rare. Nineteen different active cell types have been described and secrete (produce and release) up to 40 different hormones. Only five different functional clinical syndromes (conditions) have been described:
    1. Insulinoma - tumor or the beta cells that produce excess insulin. They are small and 90% are benign and single. Multiple tumors are evenly distributed in pancreas
    2. Gastrinoma - a non beta cell tumor that secretes gastrin that stimulates the production of stomach juices. It is small and half are malignant
    3. Glucagonoma - alpha cell tumor that secretes glucagons. It is usually large and 70% are malignant
    4. VIPoma - a non beta cell tumor that secretes vasoactive intestinal polypeptide. About 50% are malignant
    5. Somatastatinoma - a tumor of delta cells that secrete somatostatin. The tumor is large and the majority are malignant
    6. PPomas secrete pancreatic polypeptide (PP) and are not associated with a specific syndrome
  • Nonfunctioning (no secretion) tumors occur with the same frequency as functioning (secreting) tumors). Nonfunctioning islet cell tumors occur as frequently as functioning tumors. They are larger, cause local symptoms and 80% are malignant
  • The diagnosis of malignancy with endocrine tumors requires the presence of metastasis (tumor going to another organ). The metastatic sites are usually liver, regional lymph nodes, peritoneum and bone

History and Exam

  • Symptoms suggestive of acute pancreatitis are abrupt onset of epigastric (just below the ribs) pain, nausea and anorexia (no desire to eat). It is frequently associated with gallstones or recent alcohol binge
  • Adenocarcinoma of the pancreas presents with weight loss, epigastric pain, anorexia and frequently with onset of diabetes mellitus within the past two years. Unfortunately, the symptoms occur when the disease is relatively advanced. Pancreatic cancer often presents with painless jaundice
  • Nonfunctioning endocrine tumors present much like adenocarcinoma of the pancreas
  • Functioning endocrine tumors present with symptoms referable to the excess hormone:
    1. Insulinoma - excess insulin and presents with psychosis, palpitations, tremors and weight gain
    2. Gastrinoma - excess gastrin with severe ulcer disease with epigastric pain
    3. Glucogonoma - excess glucogon with glucose intolerance, weight loss and rash
    4. VIPoma - excess vasoactive intestinal polypeptide with severe watery diarrhea
    5. Somatostatinoma - excess somatostatin with diarrhea, weight loss, diabetes, gall stones and fatty stools
  • Jaundice is present in 70-80% of cancer of the head of pancreas. A mass may be felt in the epigastric area or a distended gall bladder may be felt in the right upper quadrant (Courvoisier's sign). When the mass can be felt on examination it indicates advanced disease

Tests

Tests are carried out to make the diagnosis and determine the extent of the disease. The following tests are helpful:

  • Ultrasound - A sound generator and detector produce a picture using sound waves. It evaluates the head of pancreas better than body and tail. Also evaluates the liver and biliary tract. It is non invasive and inexpensive
  • Computed Axial Tomography (CAT scan) - CAT with intravenous (by vein) and oral (by mouth) contrast is the best method for diagnosis and staging if the tumor is greater than 1 centimeter in size. This test has 70-95% accuracy in determining whether the tumor can be removed by surgery (Figure 4)
Figure 4 - Tumor of the tail of the pancreas as seen on CT scan of the abdomen. A needle is seen being passed into the tumor for biopsy. Courtesy S. Sadiq, MD
  • Magnetic Resonance Imaging - MRI - has only limited usefulness and is expensive
  • Endoscopic Retrograde Cholangiopancreatography - ERCP - A lighted tube connected to a TV camera is inserted and provides evaluation of the esophagus, stomach and duodenum. With injection of dye this test can outline the biliary and pancreatic ducts · Endoscopic Ultrasonography - EUS - The sound generator/detector is inserted into the duodenum. It shows promise in evaluating the head of pancreas
  • Angiography - This is a dye study of the blood vessels. It is used infrequently. It is helpful in identifying functional endocrine tumors · Fine Needle Aspiration - FNA - There is aspiration (removal by suction) of cells from pancreatic mass under ultrasound or CAT guidance. It is helpful when the aspirate is positive for malignancy. A negative aspirate doesn't exclude malignancy. It is difficult in small tumors (Figure 4)
  • Blood chemistries - abnormal liver function studies are common. Functioning endocrine tumors will have elevated hormone levels that are specific to the tumor type
  • Laparoscopy - A lighted tube with lenses at one end and a TV camera at the other is inserted into the abdomen. Pancreatic cancer has high incidence of spread to liver and peritoneum (the thin lining of the abdomen) making it impossible to remove. It is helpful in preventing unnecessary open surgery for diagnosis and determination of therapy

Indications and Contraindiations

  • Any congenital anomaly that causes symptoms requires surgery
  • Surgery for acute pancreatitis is for the complications:
    1. A biliary stone that causes obstruction and jaundice should be removed either through an endoscopic that is passed down through the stomach and duodenum into the bile duct or by surgery to remove the stone
    2. Surgery may be required for necrosis (death of tissue) with infection, abscess, pseudocyst, or hemorrhage
    3. Symptomatic chronic pancreatitis may occasionally warrant surgery
  • Any suspected benign or malignant tumor is considered for surgery. Tumors that cannot be removed (75 - 85% of cases) frequently require a bypass because of bile duct obstruction or impending stomach outlet obstruction
  • Contraindications are based upon the individual's physiologic reserve. Pancreatic cancers occur most often in older people and big operations are required to remove the cancers

Surgical Procedures

  • Symptomatic obstructing annular pancreas is treated with a bypass operation. The stomach is anastomosed (surgically connected) to a loop of jejunum thus bypassing the obstructing pancreatic tissue, which is not removed (Figure 5)
Figure 5 - An obstruction of the duodenum can be bypassed by a stomach to jejunum anastomosis © C. McKee
  • Surgery may be necessary for the complications of acute pancreatitis. Necrotic pancreatic and tissue around the pancreas may become infected and require debridement (removal of dead tissue) and drainage
  • Pseudocysts, when mature with a good capsule, may be drained into the intestinal tract by anastomosing the wall of the mature cyst to the stomach or small bowel (Figure 6)
Figure 6 - The contents of a pancreatic cyst may be drained into the bowel by a cyst to jejunum roux en Y (Y-shaped) anastomosis. © C. McKee
  • Chronic pancreatitis may cause strictures of the ducts and present with marked ductal dilatation. A dilated main pancreatic duct causing unrelenting pain may be treated by an anastomosis to small bowel limb. Severe chronic pancreatitis is occasionally treated with a 95% resection of the pancreas with preservation of the common bile duct and 5% of the head of the pancreas
  • Cancer of the ducts of the head of the pancreas is treated with a pancreaticoduodenectomy (Whipple procedure). This procedure involves removal of the head and neck (the part near the curve of the duodenum) of the pancreas plus the gall bladder, lower common bile duct, lower stomach, entire duodenum and nearby lymph nodes (Figure 7)
Figure 7 - This procedure involves removal of the head and neck of the pancreas plus the gall bladder, lower common bile duct, lower stomach, entire duodenum and nearby lymph nodes. The bowel is reconstructed as shown and as noted in the text. © C. McKee
  • Reconstruction requires anastomosis of the pancreas to the jejunum, common hepatic duct to the jejunum, and stomach to the jejunum
  • A modification of the standard Whipple allows preservation of the stomach and a small cuff of duodenum
  • A tube is frequently placed in the stomach to remove fluid and air and a feeding tube placed in the jejunum
  • Cancer of the body and tail of the pancreas requires removal of the body and tail plus the spleen (Figure 8)
Figure 8 - Removal of the body and tail of the pancreas for tumor showing the additional removal of the adjacent spleen. © C. McKee
  • Benign (non-cancerous) endocrine tumors can often be treated by simple removal of the tumor
  • Malignant endocrine tumors are treated similar to ductal carcinomas
  • Tumors that cannot be removed often require internal drainage procedures to relieve bile duct obstruction or stomach outlet obstruction
  • Biliary drainage can be accomplished by anastomosing the common bile duct or common hepatic duct to a roux en y jejunal limb after removing the gall bladder (Figure 9)
Figure 9 - Roux en Y anastomosis of common bile duct to the jejunum to bypass an obstruction of the end of the bile duct. © C. McKee
  • Occasionally, biliary drainage will be performed by anastomosing the gall bladder to a loop of jejunum
  • Obstruction of the duodenum may be prevented by anastomosing the stomach to the jejunum (gastrojejunostomy) (Figure 7)
  • Jaundice due to obstruction of the common bile duct may be drained by open surgery or by non-open procedures. These non-open procedures have a higher failure and infection rate
    1. Endoscopic stenting of the common bile involves the passing of a lighted tube attached to a monitor through the mouth into the stomach and duodenum and then into the common bile duct. A stent (an expandable metal cage) is then guided through the obstruction expanded to relieve the jaundice
    2. Percutaneous transhepatic drainage of the common bile duct is possible by placing a catheter into a liver duct and passing a guide wire through the bile ducts into the duodenum. A stent is then threaded over the guide wire and left in the common bile duct and duodenum to provide drainage
    3. Radiation (X-ray therapy) is used to obtain the best possible results in ductal cancer. Sensitizing chemotherapy (drug therapy) can be used to enhance the radiation therapy. Endocrine tumors are less responsive to radiation therapy and chemotherapy is used extensively in treating these tumors

Complications

  • The operative mortality for pancreaticoduodenectomy in most large series ranges between 0 - 15%. Postoperative morbidity (difficulties) approaches 50%
  • The complications most often encountered are:
    1. Hemorrhage
    2. Infection
    3. Abscess inside the abdomen
    4. Fistulas - anastomotic leaks - from the pancreas, bile duct and stomach
    5. Delayed emptying of the stomach
    6. Pancreatitis
    7. Diabetes mellitus and inadequate pancreatic exocrine function
    8. Other organ failure - heart, lung, kidney, liver

Care After Surgery

  • Vital signs (blood pressure, temperature, heart rate, and respiratory rate) are performed every 1-4 hours for the first 24 hours and tapered gradually
  • Urine output is checked every 2-4 hours the first day, less frequently the second day and the bladder catheter is usually removed the 3-4 day
  • The nasogastric (nose to stomach) tube is irrigated every 4-6 hours and usually removed by the 3rd or 4th day
  • Intravenous (IV) fluids are usually necessary for 3-4 days or until the patient is drinking adequately
  • Pain control medications are given intravenously for 2-3 days and intramuscular (in the muscle) or by mouth later
  • Antibiotics are given for several days
  • Anticoagulants (blood thinners) are usually given subcutaneously (under the skin) every 8-12 hours until the patient is actively walking
  • Deep breathing is encouraged frequently and emphasized
  • Ambulation is started the first day and as frequently as possible
  • A few laboratory studies such as a complete blood count, urinalysis, electrolytes, calcium and blood sugars are obtained
  • A chest X-ray may be necessary if lung complications are suspected · Nutrition may be given IV · Tube feedings to enhance nutrition may be necessary in certain situations

After Discharge

  • The patient usually sees the surgeon in the office 5-10 days after discharge
  • There is no heavy lifting or straining for 6-8 weeks
  • The patient may return to work 2-3 months after surgery
  • Malignant conditions always require assessment for radiation or chemotherapy
  • The patient should continue with the prescribed medications
  • The surgeon is usually seen before returning to work and at recommended follow up