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procedures. Uncomplicated Barrett's esophagus is a controversial indication for an antireflux procedure, as available studies do not agree as to whether or not surgery reverses the mucosal changes associated with Barrett's esophagus. Confirmed severe dysplasia is an indication for esophagectomy, not antireflux surgery. Gastroesophageal reflux is associated with a lower esophageal sphincter pressure. Esophageal dysmotility is a contraindication to reflux surgery. Esophagitis should heal with appropriate medical management.

13.The answer is B (Chapter 10, V A , V B , V C). This patient's history, physical examination, and diagnostic studies are consistent with an acute esophageal perforation, and the situation represents a surgical emergency. Whenever possible, primary surgical repair is indicated regardless of the time since perforation. If sepsis and regional inflammation preclude primary repair, resection with cervical esophagostomy and gastrostomy and jejunostomy tube insertion should be performed. Restoration of alimentary continuity with stomach or colon can then be performed in 2–3 months.

14.The answers are 14 -C (Chapter 11, IV A 4–5 ). Benign gastric ulcers should heal in 8–12 weeks with maximal medical therapy. If the ulcer does not heal completely during this time period, repeat endoscopy should be performed with biopsy. If gastric adenocarcinoma is diagnosed in this location, the optimal surgical therapy for this condition would be a distal gastrectomy with D1 (regional) lymph node dissection. More extensive surgery, such as total gastrectomy or splenectomy, would be reserved for more proximal gastric lesions. Neither radiation therapy followed by chemotherapy alone without surgery or limited surgery followed by radiotherapy is a treatment plan with curative intent.

15.The answers are 15 -B (Chapter 11, V C 2 h [1] [c]). Benign gastric ulcers should heal in 8–12 weeks with maximal medical therapy. If the ulcer does not heal completely during this time period, repeat endoscopy should be performed with biopsy. If gastric adenocarcinoma is diagnosed in this location, the optimal surgical therapy for this condition would be a distal gastrectomy with D1 (regional) lymph node dissection. More extensive surgery, such as total gastrectomy or splenectomy, would be reserved for more proximal gastric lesions. Neither radiation therapy followed by chemotherapy alone without surgery or limited surgery followed by radiotherapy is a treatment plan with curative intent.

16.The answer is B (Chapter 11, IV B 5 c). Parietal cell vagotomy, also termed highly selective vagotomy , maintains the nerves of Laterjet that innervate the pylorus. By dividing only the branches that innervate the parietal cells, pyloric function is preserved and outflow of the stomach is maintained. It is a technically demanding operation, in that failure to adequately sever the appropriate nerves will result in recurrences of more than 10%. However, parietal cell vagotomy can be performed for bleeding or perforated ulcers.

17.The answer is B (Chapter 11, I B 5). The vagal nerves are one of the principal stimulants of gastric acid secretion through direct stimulation of the parietal cells and via gastrin release from antral cells. Although the splanchnic and celiac ganglions are important in gastric motility and sensation, they do not stimulate acid secretion. The T4 root and phrenic nerve are not involved in gastric nervous supply.

18.The answer is C (Chapter 12, I B 2). Both parathormone and vitamin D increase intestinal absorption of dietary calcium. Bile salts are essential for absorption of fats and fat -soluble vitamins. Vitamin B 12 is a water -soluble vitamin that

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stomach, and the protein–vitamin B 12 complex is absorbed in the terminal ileum. The range of iron absorption is only 10%–

26% of dietary iron. Triglycerides are not absorbed intact but must first be broken down into free fatty acids and monoglycerides. Once absorbed, they are resynthesized into triglycerides, but they are not released into the portal circulation. Rather, the triglycerides are packaged as chylomicrons and released into the lymphatic circulation.

19.The answer is E (Chapter 12, II B ). The diagnosis of Crohn's disease is supported by the enterovesical fistula, the presence of “fat wrapping” of the bowel, inflammation, and the clinical history. To prevent ongoing contamination of the urinary tract, the fistula must be closed, and resection of the involved segment of bowel would be the standard approach. Regarding the extent of resection, the 50% risk of recurrence is not decreased by more extensive resections, thus the less bowel removed the better. In this case, with three widely separated segments of ileum involved, removal of all involved bowel could result in loss of more than half of the ileum and would not be advisable. Crohn's disease does not directly involve the bladder and thus resection of the bladder wall is unnecessary except when needed to close the opening of the fistula. Meckel's diverticulum occurs proximal to the terminal ileum; it would not affect multiple bowel segments and does not cause “fat wrapping.”

20.The answer is B (Chapter 12, II B ). This patient presents with recurrent Crohn's disease in the form of an obstruction from stricture, which is the most common manifestation that requires surgery. After surgery, the risk of recurrent manifestations of Crohn's disease requiring reoperation is 50%, and the risk remains 50% after each surgical procedure. Strictures, unlike fistulas and perforations, can be treated via bypass of the involved segment of bowel, although resection is preferred except when the risk is too great. The risk of cancer is related to the chronicity of the disease and would almost

never require extensive small bowel resection, which may leave the patient with short bowel syndrome (a difficult disorder to treat in this population). Postoperative anastomotic strictures cause symptoms very early postoperatively, not years later. If this patient had previously had a resection of the terminal ileum, he would develop a deficiency of vitamin B 12 , not folate.

21–23. The answers are 21 -E (Chapter 12, II B 5), 22 -D (Chapter 12, II B 3, 5), 23 -C (Chapter 12, I B 2 f–g ; II B 4–6). When surgery is necessary to treat complications of Crohn's disease, the operations are “conservative,” as defined by the length of the resection. Therefore, when an obstructive lesion is present, only a short length of bowel needs to be resected. In the case described, the distal ileum and cecum should be removed. Radical resections are not necessary, as they do not reduce the risk of recurrence and may ultimately contribute to short bowel syndrome if several resections are required over long periods. In addition, resection of mesentery and lymph nodes (e.g., for a cancer operation) is unnecessary. Bypass procedures without resection are reserved for only the most difficult cases where resection cannot be undertaken safely. A stricturoplasty is appropriate occasionally for short symptomatic strictures in the small bowel only.

The second postoperative week is the usual time for the development of serious complications, such as abdominal wound dehiscence, intestinal anastomotic breakdown, and intraperitoneal abscess. Blind loop syndrome occurs rarely; and although it does cause pain and diarrhea, it does not cause fever and ileus. Pyelonephritis usually causes flank pain and pyuria. Crohn's disease does not recur immediately or cause the signs unless complications have occurred. Pseudomembranous enterocolitis causes tenderness over the transverse colon and occasionally over the descending colon, with diarrhea. Of the choices listed, an intra -abdominal abscess is the most likely diagnosis.

The prognosis of Crohn's disease, which requires surgery, is not good because 50% of patients require additional surgical procedures within 5 years of the first operation. Therefore, the chance of cure is less than 50%. Medical therapy (including anti -inflammatory agents and antibiotic drugs) has not proved effective for preventing recurrence of the disease. Removal of the terminal ileum has no effect on disease recurrence or iron absorption; however, the absorption of vitamin B 12 is

significantly impaired.

24–25. The answers are 24 -C (Chapter 13, VIII A 6; XIV B 3), 25 -C (Chapter 13, XV A 3 a). Flat plate and erect radiographs of the abdomen should be performed first. Further studies may be needed based on the results of this initial survey. As with all bowel obstructions, the initial treatment involves nasogastric suction, intravenous fluids, and resuscitation with careful attention to correcting metabolic and

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electrolyte abnormalities. Once a patient has been adequately resuscitated, the decision to either observe carefully or intervene operatively can be made.

26–27. The answers are 26 -D (Chapter 13, VIII C 1), 27 -A (Chapter 13, VIII D 2). Crampy abdominal pain and diarrhea after a course of antibiotic therapy is highly suggestive of antibiotic -associated or pseudomembranous colitis. Diagnosis can be made either by proctoscopy, which demonstrates pseudomembranes, or by stool titer for Clostridium difficile toxin. Proctoscopy establishes the diagnosis immediately. Barium enema is contraindicated. The antibiotics should be stopped, and the patient should be started on metronidazole. Oral vancomycin is also effective, but it is more expensive. Colectomy is rarely required only in severe cases.

28.The answer is A (Chapter 12, II C). Meckel's diverticulum is the most common diverticulum of the gastrointestinal tract and goes by the rule of 2's: 2 ft from ileocecal valce, 2% incidence, 2 cm long, 2:1 male to female ratio. They can cause bleeding due to heterotropic gastric mucosa as well as intussusception and obstruction. An asymptomatic Meckel's diverticulum should not be resected.

29.The answer is C (Chapter 13, IV D 5 a–b ). CT scan of the abdomen and pelvis is the most helpful test to confirm the suspected diagnosis of diverticulitis. Free air is detected on the chest radiograph in less than 3% of patients with diverticulitis. Contrast enema should generally be avoided in the initial stages of diverticulitis. Colonoscopy to exclude a sigmoid cancer may be of value after the condition of the patient has stabilized.

30.The answer is C (Chapter 13, XII C 1 f (1)). This patient presents with a classic history and physical findings of perirectal abscess. Antibiotic therapy will not cure an abscess. Definitive drainage is required. This therapy will be curative in approximately 50% of the patients, and the remainder will develop a fistula. However, the physician should deal with the abscess itself at the initial presentation. Attempts to definitely address any fistula tract at initial presentation is not recommended due to potential complications such as injury to the sphincter muscles and difficulties with continence.

31–32. The answers are 31 -D (Chapter 14, I C 2 a, d), 32 -D (Chapter 14, I C 2 a, d). Although many liver tumors undergo spontaneous hemorrhage, this condition occurs most frequently with hepatic cell adenomas. Up to 30% of patients present with spontaneous rupture into the peritoneal cavity as their initial finding.

The patient continues to bleed. Emergency liver resection after an acute rupture would be associated with high morbidity and mortality. While hepatic artery ligation may control the bleeding, this can probably be accomplished less invasively by radiologic embolization. Once the bleeding is controlled and the patient recovers, elective resection should be undertaken to avoid future hemorrhage.

33. The answer is E (Chapter 13, V D). Cases of diverticulitis complicated by perforation and abscess formation are best managed by percutaneous drainage in the absence of evidence of diffuse peritonitis. Young patients (typically considered as being less than 50 years of age) with a single severe case such as this should be considered for an interval resection of the diseased section of bowel because of the very high risk of subsequent severe episodes. Older patients are often referred after a second episode. Colonoscopy should not be routinely performed during the acute phase of an episode of diverticulitis but should be performed prior on an interval basis. Operative intervention during the acute phase is reserved for cases that either present with diffuse peritonitis, perforation or continued worsening of the clinical picture in spite of appropriate non - operative therapy. Primary anastomosis is typically avoided in the setting of severe infection and contamination.

34–36. The answers are 34 -C (Chapter 14, II E 3 a), 35 -D (Chapter 14, II B 3), 36 -A (Chapter 14, II H 3 a–b, 4 ). Acute variceal bleeding commonly occurs because of portal hypertension from underlying cirrhosis. Other causes of upper gastrointestinal bleeding that must also be considered in these patients include gastritis and peptic ulcer disease. Upper gastrointestinal endoscopy is the most rapid way of making the diagnosis of the site and identifying the cause of upper gastrointestinal bleeding. Once the diagnosis has been made, sclerotherapy is the preferred method of managing acute variceal bleeding. It is successful in 90% of patients.

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Portacaval shunt, mesocaval shunt, sclerotherapy, transjugular intrahepatic portosystemic shunt, and selective Warren shunt for recurrent bleeding would potentially be successful in preventing long-term hemorrhage. However, portacaval shunt would make a subsequent liver transplant extremely difficult and hazardous.

37. The answer is D (Chapter 14, III F ). Cholangitis is a potentially life -threatening disease. This patient is present with Charcot's triad of pain, fever, and jaundice.

38–39. The answers are 38 -D (Chapter 15, II C), 39 -E (Chapter 15, II C). Uncomplicated acute pancreatitis is best managed conservatively with nasogastric decompression, intravenous hydration, bowel rest, and pain medicine. Imaging with ultrasound, CT scan, magnetic resonance imaging, or magnetic resonance cholangiopancreatography can be useful in establishing a possible etiology (gallstones) or detecting complications. Endoscopic retrograde cholangiopancreatography (ERCP) should not be used routinely during the acute presentation due to the risk of ERCP -associated pancreatitis complicating the acute situation. ERCP should be reserved for specific cases where there is evidence of biliary obstruction. Evaluation of pancreatic duct anatomy can be helpful on an interval basis to help assess causes of chronic or recurrent pancreatitis.

40.The answer is A (Chapter 15, III A ). When patients are unresectable due to distant metastases at the time of surgery, a surgeon must accomplish several things. A biliary bypass (hepaticojejunostomy) palliates the obstructive jaundice, and a cholecystectomy is performed in conjunction with this. A gastric bypass (gastrojejunostomy) prevents the gastric outlet obstruction observed in 19% of unresected periampullary cancer patients. A celiac axis nerve block has been shown to significantly reduce cancer -related pain. A surgeon must also make a tissue diagnosis, in this case by taking a biopsy of one of the liver metastases. An additional pancreatic biopsy is unnecessary and adds additional risks.

41.The answer is E (Chapter 15, III A ). Findings that determine unresectability on preoperative CT scan include encasement of the superior mesenteric artery or proximal celiac axis and occlusion of the superiormesenteric vein or portal vein. Tumor abutting these vessels but not encasing or occluding them is not a contraindication to resection. The gastroduodenal artery is ligated during a pancreaticoduodenectomy, thus its occlusion does not preclude resection. A replaced right hepatic artery is not uncommon and must be preserved. This does not, however, preclude resection.

42–46. The answers are 42 -C, 43 -E, 44 -A, 45 -B, and 46 -D (Chapter 11, I B 3; Chapter 11, II B 1). The blood supply of the viscera is important in gastrointestinal surgery. Three of the four main arteries can be sacrificed, and blood flow to the stomach will still be preserved through collateral circulation. The proximal lesser curvature is supplied by the left gastric artery (arising from the celiac axis). The right gastric artery (arising from the common hepatic artery) supplies the distal lesser curvature. The left and right gastroepiploic arteries supply the proximal and distal greater curvature, respectively. The duodenum and head of the pancreas are supplied by the superior and inferior pancreaticoduodenal arteries that arise from the gastroduodenal and superior mesenteric arteries, respectively. The body and tail of the pancreas are supplied by branches of the splenic artery.

Chapter 16

Thyroid, Adrenal, Parathyroid, and Thymus Glands

John S. Radomski

Herbert E. Cohn

John C. Kairys

I Thyroid Gland

Indications for operations on the thyroid gland have varied since excision was first described by Kocher in the late 1800s. In early years, operations on the thyroid were performed primarily to relieve the pressure symptoms of large iodine -deficiency goiter, to control hyperthyroidism, or to remove thyroid neoplasms. With the advent of iodized salt, iodine -deficiency goiters have been almost eliminated, and hyperthyroidism is now controlled mainly by nonoperative means. However, surgery remains the mainstay of treatment for thyroid neoplasms and, in many instances, is important in their diagnosis.

A Vasculature of the thyroid gland

(Fig. 16 -1)

Arterial supply

The superior thyroid artery , which is the first branch of the external carotid artery, supplies the upper pole of the thyroid.

The inferior thyroid artery , which arises from the thyrocervical trunk of the subclavian artery, supplies the lower pole of the gland.

A thyroidea ima artery occasionally arises from the aortic arch and connects to the thyroid isthmus inferiorly.

Venous drainage of the thyroid is an interconnecting system of veins without valves.

The superior thyroid veins drain along the course of the superior thyroid arteries into the internal jugular vein.

The middle thyroid vein drains directly into the internal jugular vein.

The inferior thyroid veins drain from the lower pole and isthmus either directly into the internal jugular vein or into the innominate vein.

Lymphatic drainage

Lymphatics from the thyroid gland always drain to the ipsilateral cervical lymph nodes in either the anterior or posterior triangle of the neck, along the course of the internal jugular vein to the nodes in the tracheoesophageal groove, or to the paratracheal nodes in the mediastinum.

The nodes in the tracheoesophageal groove are most important in the spread of thyroid malignancies because involvement of these nodes may cause tumor extension into the underlying recurrent nerve, trachea, or esophagus.

B Nerves related to the thyroid gland

Recurrent (inferior) laryngeal nerve

Course. The recurrent laryngeal nerve runs in the tracheoesophageal groove in intimate relationship to the posteromedial aspect of the thyroid gland.

On the right, the nerve recurs around the subclavian artery and runs an oblique course from lateral to medial, crossing the inferior thyroid artery before entering the tracheo -esophageal groove.

On the left, the nerve recurs around the ligamentum arteriosum in the mediastinum and runs a course parallel to the tracheoesophageal groove throughout its course in the neck.

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FIGURE 16-1 Blood supply of the thyroid. (Reprinted with permission from Edis AJ, Grant CS, Egdahl RH. Comprehensive Manuals of Surgical Specialties— Manual of Endocrine Surgery, 2nd ed. New York: Springer-Verlag; 1984:75.

)

Branches. The nerve divides into an external branch, which is sensory to the larynx, and an internal branch, which supplies the intrinsic muscles of the larynx.

Injury to the recurrent laryngeal nerve most commonly occurs where the nerve crosses the inferior thyroid artery or where it penetrates the cricothyroid membrane, but injury can occur anywhere along its course (see I D 2 e [4] [d]). Injury can be avoided by visualizing the nerve throughout its course during operations requiring complete thyroid lobectomy.

Superior laryngeal nerve

Course. The nerve is intimately intertwined with the branches of the superior thyroid artery.