Abdominal Surgery

·         Pancreatic and salivary amylase break the interior 1-4 glucose linkages.

·         Foregut carcinoid tumors, of which stomach and bronchial tumors are the most common, can cause atypical carcinoid syndrome. It is thought that these tumors are deficient in the enzyme dopa-decarboxylase and have impaired conversion of 5-hydroxytryptophan (5-HTP) into 5-hydroxytryptamine (5-HT), leading to secretion of 5-HTP into the vascular compartment. Some of the 5-HTP is converted into 5-HT and 5-hydroxyindoleacetic acid (5-HIAA) in extrarenal sites, and some is decarboxylated in the kidney and excreted into the urine as 5-HT; but some of the 5-HTP is excreted directly into the urine. Thus, in patients with foregut tumors, the urine contains relatively little 5-HIAA (but more than normal) but large amounts of 5-HTP and 5-HT, in contrast to patients with midgut carcinoid tumors in which large amounts of 5-HIAA are secreted into the urine but relatively little 5-HTP. Carcinoid tumors of the hindgut contain no argentaffin or argyrophil cells, they have no secretory products, and therefore they are not associated with the carcinoid syndrome. The long-acting somatostatin analog provides the best symptomatic therapy, because somatostatin inhibits both release and action of humoral mediators of the carcinoid syndrome.

·         The migrating motor complex (MMC) is a cyclic pattern of spike bursts and muscular contractions that migrate from the duodenum to the terminal ileum. The MMC is divided into four phases:

1.       Phase I-the period of quiescence with no activity;

2.       Phase II-accelerating irregular spike activity;

3.       Phase III-the activity front with a series of high-amplitude, rapid spikes corresponding to strong, rhythmic gut contractions; and

4.       Phase IV-subsiding activity. In humans the cycle lasts about 90 to 120 minutes.

·         The endocrine functions of the small intestine are diverse with an ever increasing number of hormones, peptides, neurotransmitters, and paracrine substances identified.

Cholecystokinin (CCK) is produced by cells located primarily in the mucosa of the duodenum and jejunum and released in response to luminal fats and proteins. After CCK release from the duodenum and jejunum, the gallbladder contracts and the sphincter of Oddi relaxes, emptying bile into the duodenum. Secretin is found in the S cells of the duodenum and jejunum.

Secretin, a true hormone, is released in response to acid in the duodenum when luminal pH falls below 4.5. Intraduodenal secretion of pancreatic bicarbonate neutralizes duodenal pH and results in diminished release of secretin. CCK acts in a synergistic fashion with secretin to stimulate pancreatic exocrine function.

Motilin is a 22-amino acid peptide localized in the enterochromaffin cells of the mucosa of the upper small intestine. Motilin likely has a physiologic role in the regulation of the migrating motor complex (MMC). Motilin is released during the fasting state, and increased levels correspond with the onset of the MMC.

Neurotensin is a 13-amino acid neurotransmitter found in the central nervous system and in the gut. Specific endocrine cells that contain neurotensin are found in the ileal mucosa with smaller quantities found in the jejunum, stomach, duodenum, and colonic mucosa. Neurotensin is released by a mixed meal and fats, with carbohydrates and protein releasing much smaller increments. It has been proposed that neurotensin has a physiologic role in fat-initiated changes in gastric acid secretion, gastric emptying, pancreatic secretion, and intestinal motility.

·         The reabsorption process of bile is both passive and active.

Passive absorption occurs along the entire length of the small bowel and depends on the lipid solubility of the bile salt. Glycine bile conjugates are more soluble than taurine conjugates. As much as 50% of bile is passively reabsorbed.

Active absorption of bile occurs only in the terminal ileum. A small amount of bile escapes into the colon, where it is deconjugated by bacteria, promoting lipid solubility and further passive absorption. High colonic concentration of bile salts promote diarrhea by inhibiting sodium and water absorption. This commonly occurs in patients with ileal resection and can be treated with the bile-binding resin, cholestyramine.

·         The jejunum is the site of maximum absorption of all ingested materials expect for vitamin B12. Although its mucosa contains numerous specific transport processes, the presence of large intercellular pores produces a permeable membrane and allows for rapid passive transfer or solutes and water. The ileum is less permeable and makes greater use of active-transport mechanisms.

·         When a loop of bowel is obstructed, intestinal gas and fluid accumulate. Approximately 80% of the gas seen on plane abdominal radiographs is attributable to swallowed air. In the setting of acute pain and anxiety, patients with intestinal obstruction may swallow excessive amounts of air.

·         n-Butyrate, one of the short-chain fatty acids produced by bacterial fermentation, is the preferred fuel of the colonic epithelium. The colonic epithelium utilizes n-butyrate as a fuel for the absorption of sodium and water.

·         The colonic microflora is relatively stable with a predominance of anaerobic bacteria. Typical species are Bacteroides, Bifidobacterium, and Enterobacterium.

·         It has become increasingly important to distinguish between ulcerative colitis and Crohn's colitis, since the operative therapy for the two disease processes is quite different. Patients with ulcerative colitis are candidates for colectomy with ileoanal anastomosis, whereas Crohn's disease is a clear contraindication to this operation. Clinical findings suggestive of Crohn's disease include anal fistula or other perianal disease, though it must be kept in mind that approximately 10% of patients with ulcerative colitis may also develop perianal problems secondary to their chronic diarrhea. Endoscopic or radiographic evidence of rectal sparing is powerful evidence against a diagnosis of ulcerative colitis. Transmural inflammation and granulomas on surgical pathologic specimens are pathognomonic of Crohn's disease.

·         Hidradenitis suppurativa is an inflammatory process of the sweat glands characterized by abscess and sinus formation. The disease may involve other areas where apocrine glands are present, such as the axilla, mammary, inguinal, and genital regions. The affected areas have a blotchy, purplish appearance with numerous sinuses draining watery pus. The condition must be differentiated from cryptoglandular fistulas, which communicate with the dentate line, and Crohn's disease, which may track to the anorectum proximal to the dentate line. Treatment consists of unroofing sinuses for limited disease and wide local excision for more advanced disease.

·         Colonic inertia, or slow transit constipation, is primarily a disease of young women. Despite attempts at initiating bowel movements with fiber supplementation, large doses of laxatives and enemas, normal bowel movement patterns are not established.

The etiology of this condition is totally unknown, but a likely etiology is some aberration in the neurochemical control of the colon, possibly within the enteric nerves. Abnormalities within the neural elements of the myenteric plexus suggest that disturbances in neuromodulation of colonic motility may play a role in some patients.

The treatment of colonic inertia has proved difficult and many patients have required subtotal colectomy to correct the severe constipation.

Diagnosis of this condition is usually achieved by assessing colonic transit with various radio-opaque markers. After ingestion of such markers, sequential abdominal films are taken to assess movement of markers in each segment of the colon. Total transit time in normal subjects averages about 35 hours. Total transit time in excess of 72 hours is clearly abnormal.

·         C. difficile COLITIS:

The fecal leukocyte test is a simple, rapid screening measure that is sometimes useful in supporting the diagnosis of C difficile colitis. The finding in stained smears of 3 to 5 leukocytes in at least 5 high-dry fields suggests colitis and is strongly against the diagnosis of benign or simple antibiotic-diarrhea, but it is not specific for C difficile. A positive test indicates mucosal inflammation and excludes the benign form of antibiotic diarrhea; however, no more than a third of patients with C difficile colitis have positive fecal leukocyte tests.

The isolation of C difficile from stools of a patient with diarrhea does not by itself prove the patient has colitis caused by C difficile, because about 25% of isolates of C difficile obtained from humans are nontoxigenic and nonpathogenic. In addition, at least 3% of healthy adults are asymptomatic carriers off toxigenic isolates of C difficile.

Cell culture evidence for cytotoxicity by cytotoxin B is presently the most reliable laboratory aid in diagnosis of pseudomembranous colitis. This test is the "gold standard" used to evaluate all newer tests, but it is expensive, usually takes at least 24 hours, and is not readily available in most hospitals. At least 95 percent of adults with antibiotic-associated diarrhea and toxin B positive stools have colitis.

·         Whipple procedures are used for mobile tumors in the head without signs of lymph node metastases at the celiac axis or root of mesentery. Distal pancreatectomy is used for lesions of the body and tail unaccompanied by signs of spread. Total pancreatectomy is generally reserved for a few select situations in which cancer involves most of the gland but nowhere else; this is a rare event. Median survival with each procedure is about 20 months, and 5-year survival is about 15%. This procedure has about 3% operative mortality and 25% morbidity in centers with extensive experience; in other settings, the operative risk and complication rate can be much higher.

·         Serum lipase has somewhat greater sensitivity and specificity for Acute Pancreatitis; however, an isolated elevation of lipase with a normal amylase is unlikely to be caused by pancreatitis. Serum amylase levels tend to peak sooner than lipase levels, which may remain elevated for 4-5 days. Up to 30% of patients with pancreatitis have normal amylase levels, most notably alcoholics with chronic "burned-out" pancreatitis. The absolute levels do not correlate with severity of disease, although an amylase level > 500 most likely derives from the pancreas.

·         CHRONIC PANCREATITIS

1.       75% of cases are due to alcohol abuse.

2.       Symptoms include smoldering abdominal pain and evidence of pancreatic insufficiency (diabetes, steatorrhea).

3.       30% of patients may not mount hyperamylasemia due to "burned-out" pancreas.

4.       Common complications include pseudocyst, abscess, fistula, obstructive jaundice, malnutrition.

5. The Peustow procedure (a lateral Rouxen-Y pancreaticojejunostomy) lays the Roux limb of bowel directly upon the "chain of lakes" duct to provide longitudinal head-to-tail drainage. Distal pancreatectomy may be used for isolated distal disease or retrograde drainage into a pancreaticojejunostomy. A modified Whipple operation (i.e., pancreaticoduodenectomy) can also remove a nonfunctioning but painful pancreas.

·         Schistosomiasis and Katayama fever

Infection by a freshwater blood fluke that causes an initial dermatitis ("swimmer's itch") and rash followed after 1-2 months by fever, myalgias, abdominal pain, and bloody diarrhea (Katayama fever). As these parasites mate and lay eggs in the venous system, the resulting inflammation causes chronic obstructing fibrosis of the organs and vessels, which is manifested by portal hypertension. Katayama fever lasts a few weeks and is second only to malaria as a cause of chronic tropical illness. Treat with praziquantel.

·         The modified Child-Turcott-Pugh system defines three classes of liver disease based on mortality.

A.      Albumin (g/dL)

B.      Bilirubin (mg/dL)

C.      International normalized ratio

D.      Ascites

E.       Encephalopathy

1. Class A (5-6 points): 85% 2-year survival
2. Class B (7-9 points): 60% 2-year survival
3. Class C (≥ 10 points): 35% 2-year survival

MELD: The Mayo end-stage liver disease score is a completely objective measure of disease calculated with international normalized ratio (INR), bilirubin, and creatinine. In 2002, MELD was adopted by the United Network for Organ Sharing (UNOS) for determining liver transplantation priority.

MELD = 10 x [0.957 x ln (creatinine mg/dL) + 0.378 x In (bilirubin mg/dL) + 1.120 x ln (INR) + 0.643 (0 if cholestatic/alcoholic)]

·         Only about 5% of variceal bleeds in cirrhotic patients are caused by gastric varices. Portal hypertension with gastric varices and no esophageal varices is usually associated with splenic vein thrombosis. Gastric varices bleed much less frequently-but more severely-than their esophageal counterparts.

·         The Sugiura procedure consists of devascularization of the esophagus to the inferior pulmonary vein and the proximal two thirds of the stomach, splenectomy, and distal esophageal transection. The devascularization component should be done as close to the esophagus and stomach as possible. The coronary vein and paraesophageal collaterals are preserved to maintain an effective portal-systemic collateral pathway and thereby discourage reformation of varices.

·         Even a minor obstructing lesion in the extrahepatic duct system can produce cirrhosis over time, and the development of portal hypertension, ascites, and esophageal varices. Therefore, all biliary strictures should be treated unless this is not possible or there is no chance for success. The presence or absence of jaundice is of no significance.

·         In the past, choledochal cyst was treated by Roux-en-Y cystojejunostomy, but long-term results were poor. Excision of the cyst is essential to prevent recurrent pancreatitis. In addition, the development of carcinoma in about 25% of patients mandates cyst excision. Accordingly, excision of the cyst with biliary reconstruction by Roux-en-Y hepaticojejunostomy and diversion of the flow of pancreatic juice through the ampulla of Vater is currently the standard treatment.

·         Orally administered glucose stimulates a greater insulin response than an equivalent amount of intravenous glucose through the release of enteric hormones that potentiate insulin secretion. This effect is known as the ENTEROINSULAR AXIS. Gastric inhibitory polypeptide (GIP) appears to be an important regulator of this effect, although other gut peptides, such as glucagon-like peptide I (GLP-1), may contribute to this effect as well.

·         A common mistake made in the evaluation of a patient with suspected INSULINOMA is to commence the evaluation with an oral glucose tolerance test. Instead, insulinoma is most reliably diagnosed using the technique of a monitored fast.

During a monitored fast, blood for glucose and insulin determinations is sampled every four to six hours, and at the time of symptom occurrence. Hypoglycemic symptoms typically occur when glucose levels are less than 50 mg/dl, with concurrent serum insulin levels often being greater than 25 µU/ml.

 Additional support for the diagnosis of insulinoma comes from the calculation of the insulin to glucose ratio (I:G ratio) at different time points during the monitored fast. Normal individuals will have I:G ratios less than 0.3, while patients with insulinoma typically demonstrate I:G ratios greater than 0.4 after a prolonged fast.

Other measurable beta cell products synthesized in excess in patients with insulinoma include C peptide and proinsulin. Elevated levels of C peptide and proinsulin are typically found in the peripheral blood in patients with insulinoma.

The possibility of surreptitious insulin or oral hypoglycemic agent administration should be considered in all patients with suspected insulinoma. C peptide and proinsulin levels will not be elevated in patients self-administering insulin. Additionally, patients self-administering either bovine or porcine insulin may demonstrate anti-insulin antibodies in circulating blood.

·         Surgeries for GERD:

1. In the Nissen fundoplication, which is used in > 95% of patients, the fundus of the stomach is mobilized, wrapped around the distal esophagus posteriorly, and secured to itself anteriorly (i.e., 360-degree wrap). The procedure alters the angle of the gastroesophageal junction and maintains the distal esophagus within the abdomen to prevent reflux. The operation is performed transabdominally by either laparotomy or laparoscopy.
2. The Belsey Mark IV operation accomplishes the same anatomic changes but is done via a thoracotomy.
3. The Hill gastropexy restores the esophagus to the abdominal cavity by securing the gastric cardia to the preaortic fascia.
4. The Toupet (partial) fundoplication is used in patients who have associated motility disorders. Because the wrap is not circumferential, the incidence of postoperative dysphagia is significantly reduced with this partial wrap compared with a full 360-degree wrap (Nissen fundoplication). However, long-term durability may not be as good as with a Nissen fundoplication. This operation can be done transabdominally by either laparotomy or laparoscopy.

·         All gross disease is removed, and microscopically, the margins of resection are negative for tumor. Achieving an R0 resection is the surgeon's goal and is the most robust predictor of a favorable outcome after surgery for esophageal cancer. An R1 resection represents removal of all gross disease, yet resection margins are microscopically positive for tumor. The overall 5-year survival (any stage) for patients with microscopically positive margins decreases by an order of magnitude (e.g., 30% down to 3%).

·         The Billroth I operation is an anastomosis between the duodenum and the gastric remnant (gastroduodenostomy). The Billroth II operation is constructed by sewing a loop of jejunum to the gastric remnant (gastrojejunostomy). Either method is acceptable.

Billroth I has the advantages of eliminating the duodenal stump and requiring only one suture line instead of two (as in Billroth II). Duodenal stump blowout is a critical surgical emergency that requires immediate laparotomy. Afferent loop syndrome (i.e., sludging of stuff in the loop that is not in the enteric stream) is also a complication of Billroth II. Bile reflux gastritis may occur in both procedures. Billroth I is more physiologic; thus, it results in better protein and fat digestion. Billroth I is more susceptible to gastric outlet obstruction with ulcer or tumor recurrence; therefore, a Billroth I hook-up is not recommended for patients with gastric carcinoma.

·         Heinecke-Mikulicz pyloroplasty: A pyloduodenal incision along the longitudinal axis followed by a transverse closure flops the pylorus open and promotes gastric emptying.

Finney pyloroplasty: A side-to-side gastroduodenal anastomosis that transects and defunctionalizes the pylorus and promotes gastric emptying

Jaboulay pyloroplasty: This gastric emptying procedure comprises a side-to-side gastroduodenal anastomosis that does not transect the pylorus. It is ideal if severe pyloric scarring is present.

·         Graham closure: Surgical closure of duodenal ulcer by omental patch.

·         The "four-way abdominal series" (flat and upright abdominal films, plus posterolateral [PA] and lateral chest radiographs) is diagnostic about 75% of the time in Intestinal Obstruction.

·         Products purported to decrease adhesion formation:

1.       Oxidized cellulose (Interceed)

2.       Sodium hyaluronate and carboxymethylcellulose (Seprafilm)

3.       Icodextrin (Adept; investigational)

4.       0.5% Ferric hyaluronate gel (Intergel; investigational)

·         The pancreaticoduodenal arteries form the major collaterals between the celiac artery and the SMA. The gastroduodenal artery gives off the superior pancreaticoduodenal artery that encircles the head of the pancreas and anastomoses with the inferior pancreaticoduodental artery, the first branch of the SMA.

The SMA and IMA have two main connections. The marginal artery of Drummond lies within the mesentery of the colon and is made up of branches of the ileocolic, right, middle, and left colic arteries. The arc of Riolan (meandering mesenteric artery) is more central and connects the middle colic branch of the SMA and the left colic branch of the IMA.

The internal iliac artery gives rise to the middle rectal artery, which can provide flow to the superior rectal and thus the IMA.

·         NOMI accounts for approximately 25% of acute ischemic cases; arterial spasm is the most common cause. This typically occurs in critically ill patients with systemic hypoperfusion. In such low-flow states, splanchnic blood flow is reduced in attempts to preserve perfusion to cardiac and cerebral beds. Pharmacologic agents such as ergot alkaloids, digitalis, and vasoconstrictors are the "usual suspects." Cocaine-induced mesenteric ischemia has also been reported.

Angiography documents vasospasm in the absence of an anatomic occlusion. The right colon is most commonly affected because of its less consistent collateral blood flow. It is associated with (and may be exacerbated by) the concomitant use of digitalis in patients with systemic hypoperfusion. In severe cases associated with multisystem organ failure, the mortality rate approaches 75%. Treatment consists of hemodynamic optimization, weaning of inotropes, and selective arterial infusion of vasodilators (papaverine) through the angiogram catheter. Surgical intervention is reserved for intestinal infarction or perforation.

·         Celiac compression (Dunbar's syndrome) is a rare and controversial disorder most commonly described in women (female-to-male ratio = 4:1) between the ages of 20 and 50 years. Patients appear to suffer from chronic mesenteric ischemia without angiographic evidence of atherosclerotic disease. The mechanical compression is believed to be caused by the left crus of the diaphragm (i.e., marginal arcuate ligament), and diagnosis occasionally is confirmed by demonstrating transient celiac compression during expiration. The associated pain is the result of a complicated and still heavily debated redirection of flow (foregut steal) away from the SMA. Effective treatment has required not only release of the compression but also bypass to improve the likelihood of pain resolution.

·         As they apply to intestinal bypass, the terms antegrade and retrograde refer to the origin of the graft from the aorta as either proximal to the celiac axis or distal to the SMA, respectively. The stated advantages of antegrade bypass are less kinking of the graft and possibly better blood flow characteristics. The disadvantages are that supraceliac exposure is technically more difficult and clamping may result in renal or spinal cord ischemia. Retrograde bypass grafts are more difficult to position to avoid kinking.

Recent series suggest that the results for single- or multiple-vessel reconstruction in either antegrade or retrograde fashion are excellent, with symptom-free survival rates > 90% at 5 years.

·         Ogilvie's syndrome is an acute paralytic (adynamic) ileus or pseudoobstruction (i.e., enormous dilation of the colon without a mechanical distal obstructing lesion). Patients present with a massively dilated abdomen and a small amount of pain.

Nonoperative management, including bowel rest, intravenous fluids, and gentle enemas, is the therapy of choice. Gastrografin enema or colonoscopy is diagnostic and therapeutic. Neostigmine is another treatment modality in patients with colons > 10 cm in diameter.

If distension is painless and the patient shows no signs of toxicity or bowel ischemia, expectant management can be successful in about 50% of cases. If distension worsens so that the cecal diameter increases beyond 10–12 cm or if it persists for more than 48 hours, colonoscopy is recommended. Endoscopic decompression is successful in 60–90% of cases, but colonic distension may recur in up to 40% of cases. Rectal tubes are ineffective in managing distension of the proximal colon, however, such tubes may be useful after colonoscopy.

·         DIFFERENCES BETWEEN CROHN'S DISEASE AND ULCERATIVE COLITIS

1.       Rectal bleeding is uncommon in Crohn's disease but common in chronic ulcerative colitis.

2.       Terminal ileal involvement, skip areas, internal fistulas, and "thumb printing" are common in Crohn's disease but rare or absent in chronic ulcerative colitis.

3.       In ulcerative colitis, the inflammation is usually limited to the mucosa and submucosa, whereas in Crohn's disease it involves the entire bowel wall.

·         The Brooke ileostomy is the "rosebud" or full-thickness ileostomy folded over on itself for approximately 1 cm above the skin. This prevents the erosion of the skin and high-output serositis that is common with an ostomy that is flush with the skin.

·         Patients with lymph node involvement (Dukes' C) should receive chemotherapy postoperatively to treat micrometastases.

·         Retzius' space is between the pubis and the urinary bladder. Bogros' space is between the peritoneum and the fascia and muscle planes on the posterior aspect of the abdominal wall below the umbilicus and down to Cooper's ligament. Laterally, the space goes to the iliac spines. In either the open Stoppa procedure or the laparoscopic preperitoneal repair, the spaces of Retzius and Bogros are developed for mesh placement and surgical exposure.

·         Distinguishing amoebic from pyogenic liver abscess can be a diagnostic challenge. It is of major importance, however, because effective medical therapy with metronidazole can obviate the need for either percutaneous or surgical drainage in most cases of amoebic abscess. The clinical presentation for both conditions with acute onset of fever, abdominal pain, and altered liver function tests are almost identical. Important features such as travel to or origin from a high risk area is particularly important for amebic liver abscess. Routine liver chemistries and radiographic studies can rarely distinguish between amoebic and pyogenic liver abscesses. Specific serologic tests for the presence of antibody to E. histolytica are specific and sensitive for amoebic hepatic abscess being positive in 95% of the cases, and therefore, are key in distinguishing the two infections.

·         Focal nodular hyperplasia (FNH) should not be confused with a hepatic adenoma. Although FNH predominantly affects young women, it is also found in men and children. Unlike adenomas, there is no clear relationship between oral contraceptives and the development of FNH. FNH is most commonly asymptomatic and does not have a propensity to bleed or undergo malignant change. Histologically, FNH contains normal-appearing hepatocytes, bile ducts, and Kupffer cells in distinction to adenomas. Radionucleotide imaging can be useful in diagnosing FNH because FNH is the only lesion that contains Kupffer cells and therefore appears isodense rather than a filling defect. Treatment of asymptomatic patients is conservative when the diagnosis is clear. If there is doubt regarding the diagnosis, then excisional biopsy is indicated for small, easily removable lesions.

·         For decades, the mixed micelle which is composed of the amphiphatic bile salts and phospholipid was considered the primary carrier of bile. More recently, it has been demonstrated that up to 70% of the total amount of cholesterol normally found in gallbladder bile is transported and solubilized in the vesicular form. Bile vesicles are composed primarily of phospholipid of which in the human, lecithin accounts of 90% of the phospholipid content.

·         The prognosis for patients with hilar bile duct cancer (Klatskin tumors) is extremely poor with mortality rates of 80% to 90% in five years.

·         Thrombotic thrombocytopenic purpura (TTP) called Moschcowitz's syndrome, is characterized by thrombocytopenia, microangiopathy, chemolytic anemia, fluctuating neurologic abnormalities, progressive renal failure, and fever. Platelet deposits, with hyaline material composed of aggregated platelets and fibrin, occur. The cause is unknown, and the prognosis is very poor: survival is less than 10%. A combined approach using antiplatelet drugs and corticosteroids can be effective and sometimes has improved results if done with splenectomy.

Splenectomy was initially proposed for TPP but has been shown to have little benefit and instead is associated with a considerable risk of postsplenectomy sepsis. Corticosteroids and intravenous immune globulin are appropriate therapies for immune thrombocytopenic purpura (ITP), but not TPP.

·         NONSPECIFIC IMMUNE FUNCTION OF SPLEEN is largely characterized by removal of particulate matter by the macrophages. The spleen contains 25% of the fixed tissue macrophage population in the body. The spleen is more efficient than the liver at removal of incompletely opsonized bacteria. The liver is most effective at removing bacteria with a high density of surface opsonins.

The spleen also serves as a principal source of nonspecific opsonins. These include tuftsin, properidin, and fibronectin.

Tuftsin stimulates granulocyte and macrophage motility and phagocytosis.

Properdin activates the alternative pathway of the complement system, leading to complement fixation. Both the activated complement complexes and the complement products facilitate the destruction of the target organism.

Fibronectin is a macromolecule that appears to have nonspecific stimulatory activity on the processes of fibrosis and wound healing.

The specific immune functions of the spleen are principally related to its antigen-processing role, and this is in turn dependent on its unique anatomy and the circulation of lymphocytes into the spleen.

The liver, not the spleen, is the major site of synthesis of complement pathway proteins.

·         DES Rx: The recommended treatment for this relatively rare disorder is a long myotomy guided by the manometric evidence. If the LES is functioning properly, most surgeons would now recommend stopping the myotomy short of the normal lower sphincter. It should continue upward at least to the level of the aortic arch—higher if manometric findings of spasm are noted above that level. Eighty to 90% of patients treated in this fashion will experience acceptable relief of symptoms.

·         Origin of Zenker’s diverticulum is at the cricopharyngeus muscle near the level of the bifurcation of the carotid artery.