Файл: NMS Surgery_booksmedicos.org.pdf

associated with a high mortality rate. P.287

Peritoneal lavage can be useful in excluding other severe intra -abdominal processes and can be therapeutic in severe pancreatitis. However, peritoneal lavage appears to improve early mortality rates but not ultimate survival rates in acute severe pancreatitis.

Catheters can be placed percutaneously, and antibiotics can be included in the lavage solution.

Peritoneal lavage can be undertaken as part of a laparotomy performed for diagnosis and lesser sac exploration.

Complications include a deterioration of pulmonary function, which can be compromised by abdominal distention from the dialysis solutions. A high glucose load in the dialysis solution can induce severe hyperglycemia.

D

Relapsing pancreatitis frequently occurs in nonalcoholic patients and results from biliary tract disease—either calculi in the ducts or inflammation and spasm of the sphincter of Oddi.

Diagnosis of relapsing pancreatitis can be made by demonstrating the presence of biliary stones or biliary sphincter dysfunction.

US (see II C 3 d) is useful for diagnosing biliary calculi.

Microscopic examination of the bile is also useful.

Bile is aspirated through a suction tube placed in the duodenum.

The bile is examined for white blood cells (WBC), cholesterol crystals, and microspheroliths.

These signs of occult biliary disease are an indication for cholecystectomy.

Provocative testing (i.e., the Nardi test ) can show whether narcotic -induced stimulation or spasm will reproduce the abdominal pain and amylase increase.

Morphine and neostigmine are given intramuscularly, and baseline levels are obtained for glutamine -oxaloacetic transaminase and glutamic-pyruvic transaminase, γ-glutamyl transferase, amylase, and lipase.

Determinations are repeated hourly for 4 hours, and a final determination is made at 8 hours.

The test is positive if biliary pain is reproduced within 15–20 minutes after the injection and if the enzyme levels increase at least four times the baseline levels.

In the presence of sphincteric disease, the following situations occur:

Amylase levels increase whether or not the gallbladder is present.

Liver -related enzymes do not increase if the gallbladder is present and can distend to relieve pressure on the hepatic ductal system.

The Nardi test can, therefore, be used to infer sphincteric disease in any pancreatic or biliary ductal system without a gallbladder.

Although the test is controversial, it has been accurate in the diagnosis of perisphincteric disease. The test is not in common use.

At the time of surgery, the test results can be confirmed by measuring the pressure and flow in the common bile duct.

US observation of duct dilatation after secretin administration has shown promise in the diagnosis of sphincteric disease.

Treatment of relapsing pancreatitis is based on the cause.

In a patient with biliary calculi, the following procedures can be performed:

Cholecystectomy

Common bile duct exploration

Biliary manometry

Sphincteroplasty plus pancreaticobiliary septum resection

The treatment of perisphincteric disease is removal of the gallbladder and a wide sphincteroplasty that includes the pancreaticobiliary septum. The results have been very good in patients who have had a positive Nardi test.

Many patients have had a cholecystectomy, yet continue to have recurrent pancreatitis, biliary tract disease symptoms, or both.

These patients often have a positive provocative test and can be treated successfully by sphincteroplasty. P.288

Patients who have had negative provocative test require further workup, including ERCP [see III A 3 b]. Alcohol abuse should be ruled out.

Patients with severe intrinsic pancreatic disease respond poorly to sphincteroplasty.

E

Chronic pancreatitis is often progressive.

Pathologic findings include fibrosis and calcification throughout the gland.

Early pancreatic changes may consist of plugging of the small pancreatic ducts with proteinaceous material containing eosinophils.

With progression of the disease, the calcification becomes prominent, and multiple areas of ductal dilatation can result.

The ductal dilatation in its end stages produces a “chain-of -lakes” appearance.

Common bile duct obstruction or duodenal obstruction can occur in advanced cases of chronic pancreatitis as a result of inflammation in surrounding areas.

The cause is almost always alcohol related. However, certain congenital anomalies can produce chronic ductal obstruction and chronic pancreatitis.

Clinical presentation

A history of unrelenting pain is usual in advanced cases of chronic pancreatitis. The pain is usually the major indication for surgical intervention.

Pancreatic damage may be severe enough to cause pancreatic endocrine insufficiency, with impaired glucose tolerance or true diabetes.

Exocrine pancreatic insufficiency results in malabsorption, with consequent weight loss and steatorrhea.

Plain films may show the calcifications in the ductal system or may aid in delineating neighboring areas that are

caught in the inflammatory process.

Severe disease in the head of the pancreas can mimic carcinoma and cause bile duct obstruction.

Chronic pancreatitis can cause splenic vein thrombosis that may be a cause for upper GI bleeding.

Medical treatment

Analgesia

Endocrine replacement as needed

Exocrine replacement with pancreatic enzymes, such as pancrelipase (Viokase or Pancrease) or pancreozymin. Highdose pancreatic enzymes (i.e., 5 g four times daily) can suppress pancreatic secretion by the feedback phenomenon.

General measures, such as avoidance of alcoholic beverages and correction of malnutrition

Surgical treatment of chronic pancreatitis depends on the condition of the pancreatic ducts, as determined by ERCP. If ERCP is not possible and the patient must undergo an operation, pancreatograms can be obtained.

Puestow operation (Fig. 15 -2). A dilated chain-of -lakes duct is treated by wide unroofing of the duct and dilated ductules, with drainage of the entire open pancreas into a defunctionalized jejunal loop. A side -to -side procedure may be used, or the surgeon may choose an invagination in which the pancreas is placed into the jejunal loop.

Distal pancreatectomy is used to treat a distal ductal obstruction.

Duval operation (Fig. 15 -2). A proximal ductal obstruction can be treated by amputating the tail of the pancreas and draining the pancreas retrogradely into a defunctionalized jejunal loop. This is a simple operation and is not as effective or long lasting as lateral pancreaticojejunostomy.

For a patient with severe pain and a fibrotic, nondilated duct, possible surgical procedures include:

Child operation (Fig. 15 -2), which is a 95% pancreatectomy

Splanchnicectomy , either abdominal or thoracic

This procedure merely divides the splanchnic nerves and serves only to relieve the pain of pancreatitis, with no direct effect on the underlying disorder.

A splanchnicectomy also eradicates the pain from appendicitis and other intra -abdominal problems, which may lead to the delayed diagnosis of an abdominal emergency.

P.289

FIGURE 15-2 Surgical treatments for chronic pancreatitis: the Puestow, Duval, and Child operations.

Duodenum-sparing pancreatic head resection. This approach has become a popular option for patients who have had failed sphincteroplasties.

F

Pseudocyst is a late complication of pancreatitis.

Pathologic findings

The pseudocyst begins as a lesser sac collection and forms as a result of fibrosis, thickening, and organization of the organs bordering the collection.

The pseudocyst is not lined by epithelium and consists only of the inflammatory response of the neighboring organs.

The organs forming the walls are the stomach, duodenum, colon, and transverse mesocolon. The major organ involved is generally the stomach, which forms the anterior surface of the pseudocyst.

Maturation of the pseudocyst takes 3–5 weeks. It is not truly formed until the walls are sufficiently organized to become firm anatomic structures.

The natural history of the pseudocyst depends on its size. Small pseudocysts may resolve; large pseudocysts with mature organized walls generally do not resolve.

Clinical presentation

During the maturation phase, the patient recovers from a bout of pancreatitis but develops a persistent increase of amylase, a low -grade fever, a minimally increased WBC count, and chronic pain.

Continuous minor bleeding into the pseudocyst tends to cause a gradual decrease in hemoglobin and hematocrit. More significant bleeds are associated with acute abdominal pain or hemorrhagic shock. Bleeding into a pseudocyst is an indication for surgical intervention.

Pseudocysts are usually diagnosed by US or CT scan.

Treatment

The goal is to allow the maturation phase to continue until the walls of the pseudocyst have matured. P.290

The patient is generally treated with total parenteral nutrition (TPN) or an elemental diet for 3–4 weeks, until maturation has occurred. Prematurely starting the patient on a full diet is likely to cause an exacerbation of the pancreatitis.

Maturation-phase treatment sometimes must be cut short because of sepsis or hemorrhage within the pseudocyst.

Small pseudocysts may resolve with medical treatment.

Surgical treatment of mature pseudocysts

Internal drainage , if possible

The best approach is through the anterior wall of the stomach to locate the firm connection that usually exists between the posterior stomach and the pseudocyst.

The first step is to aspirate the cyst through the wall of the stomach. After aspirating the cyst, an opening is made between the stomach and the pseudocyst, and the wall of the opening is sutured for hemostasis.

The pseudocyst then drains into the stomach and generally resolves.

If the pseudocyst is not fixed to an organ that lends itself to internal drainage, a defunctionalized (Roux - en -Y) loop of jejunum may be sutured to the pseudocyst wall to establish internal drainage.

External drainage is used if the pseudocyst is not found to be mature and if suturing of the pseudocyst wall is not safe. The external drainage results in a pancreatic fistula, which usually heals with continued TPN.

Excision of a pseudocyst is rare; however, this removal may be indicated if the pseudocyst is small and is located distally in the tail of the pancreas.

III Pancreatic Malignancies

A Pancreatic adenocarcinoma

The incidence of pancreatic adenocarcinoma is rapidly increasing, especially in men.

It is now the fourth most common cause of cancer death in the United States.

It accounts for approximately 30,000 fatalities annually, according to the American Cancer Society estimate for 2003. The annual death rates for pancreatic cancer is equal to the annual incidence of the disease.

Increased risk is associated with multiple environmental factors, including tobacco use and some dietary and occupational exposures. Hereditary factors include familial cancer and polyposis syndromes. Diabetes and chronic pancreatitis are possible increased risk factors.

The tumor occurs most often in people who are between 50 and 70 years of age and has increased incidence among blacks, males, and those of Jewish descent.

Clinical presentation

Early symptoms are usually vague (e.g., epigastric pain, weight loss, backache, and depression).

Thrombophlebitis may be the initial presentation. It is migratory and ultimately develops in as many as 10% of

patients.

The symptoms at the time of presentation are related to the location of the tumor within the pancreas.

The head of the pancreas is the most common site. Tumors here produce weight loss and obstructive jaundice in 75% of patients.

The jaundice is painless, although back pain or vague abdominal discomfort may be present in up to 25% of patients at this stage.

Because of the retroperitoneal location of the pancreas, tumors must be very large or metastatic to become evident on physical examination. However, an upper abdominal mass may be palpable.

It represents the tumor mass in as many as 20% of patients and indicates incurability.

If the mass represents an enlarged, nontender gallbladder (Courvoisier's gallbladder) , the cause is most commonly an obstructing pancreatic neoplasm, but the gallbladder is palpable in fewer than 50% of patients.

P.291

Carcinomas of the body or tail of the pancreas are less common and generally present at a more advanced stage because only about 10% produce obstructive jaundice.

Diagnosis. Routine screening of asymptomatic populations is currently not feasible. Progress in serologic testing for tumor markers provides hope for the future. Definitive diagnosis requires at least a minimally invasive procedure.

Percutaneous fine -needle aspiration , which is a highly reliable technique to diagnose a malignancy, uses US or CT scanning to direct a small -bore needle to a mass. A cytologic specimen is obtained. This technique should not be used when lesions are potentially resectable.

ERCP uses a flexible duodenoscope to cannulate the pancreatic duct. Contrast medium is injected, and radiographs are taken.

Small pancreatic cancers can be found using this technique, and specimens can be collected from the pancreatic duct for cytologic examination.

Successful cannulation requires a highly skilled endoscopist. A stent is usually placed to relieve the biliary obstruction.

Endoscopic US can be combined with other endoscopic procedures. This provides very high resolution of small lesions and can allow transduodenal needle biopsies without the risk of peritoneal seeding.

Percutaneous transhepatic cholangiography is useful in the evaluation of patients who have obstructive jaundice.

With the patient under local anesthesia, a long small -bore needle is inserted through the liver into a dilated hepatic duct, and contrast medium is injected to identify the site of obstruction.

Jaundice is relieved preoperatively by passing a catheter through the site of obstruction, because very high bilirubin levels can be associated with an increased risk of postoperative complications.

Potential complications of the procedure include bleeding from the needle track in the liver and sepsis.

Treatment

Pancreaticoduodenectomy (Whipple procedure) is the standard surgical treatment for adenocarcinoma of the head of the pancreas when the lesion is curable by resection. Many patients can be deemed unresectable, as evidenced by metastatic disease identified by abdominal imaging and confirmed by percutaneous biopsy.

Resectability is determined at surgery from several criteria: