Symposium on New Methods of Treatment of Gastrointestinal Disease
Gastrointestinal Fiberoptic Endoscopy Diagnostic and Therapeutic Aspects
Thomas R. Liebermann, M.D., and Maurice Barnes, M.D.
Fiberoptic endoscopy has revolutionized the clinical practice of gastroenterology since its introduction by Hirschowitz et ale in 1958. 15 The esophagus, stomach, duodenum, and colon, as well as the pancreatic and biliary tree, may now be examined. The flexibility of these instruments allows a direct and relatively comfortable inspection of most of these structures. Most instruments are equipped with biopsy and brush cytologic capabilities. A variety of devices can be introduced through the biopsy channel including forceps for removal of foreign objects, electrocauteries, and snare devices. The use of these implements in therapy is increasing. The success of colonoscopic polypectomy has led to the development of other therapeutic modalities. However, increasing invasiveness has led to an expected increase in accidents resulting from the procedures. The importance of an expert performing these procedures cannot be overemphasized. Also, the correct interpretation of findings and safety are closely linked to the expertise of the individual doing the examination.
INDICATIONS FOR ESOPHAGOGASTRODUODENOSCOPY Esophagogastroduodenoscopy has evolved as an important diagnostic and potential therapeutic tool for many gastrointestinal diseases. Present technology enables the endoscopist to examine the esophagus, stomach, and first and second portion of the duodenum. There is still no consensus regarding indications for the procedure; however, certain guidelines may be given. From the Division of Gastroenterology, Scott and White Clinic, Temple, Texas
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Esophageal Symptoms Esophageal symptoms often require esophagogastroduodenoscopy for follow-up of radiographic findings, initial diagnosis, or institution of therapy. Dysphagia (difficulty in swallowing) or odynophagia (painful swallowing) are common symptoms for a variety of clinical disorders and require esophagogastroduodenoscopy for full evaluation. Esophageal strictures identified by barium swallow studies require esophagogastroduodenoscopy for further definition regarding benign or malignant origin. Endoscopically direct biopsies can diagnose in excess of 80 per cent of malignant strictures. The addition of brush cytology raises endoscopic identification of malignant strictures to more than 95 per cent." 25, 28 A substantial number of strictures that may be missed on barium swallow examination will be identified by endoscopy. Because it produces little or no change in mucosal silhouette, esophagitis cannot be diagnosed by barium swallow examination. Bleeding erosive esophagitis is clearly visible at endoscopy. Less severe esophagitis will be visible as only superficial erythema with friability or nodularity. Symptomatic patients with mild or healing esophagitis may have normal endoscopic findings and require either suction biopsy to demonstrate basal hyperplasia or other diagnostic tests for esophagitis." Odynophagia produced by herpes or monilia in immunosuppressed or host-compromised patients may be visualized by esophagogastroduodenoscopy, .with the use of a biopsy specimen and cytologic brushings for culture and cell Identification.": 25 Demonstration of Barrett's esophagus and its metaplasia to gastric mucosa replacing esophageal squamous mucosa may be demonstrated by esophagogastroduodenoscopy and confirmed by biopsy. Because of its premalignant potential, Barrett's mucosa should be followed at yearly intervals by esophagogastroduodenoscopy. Esophagogastroduodenoscopy is also useful for identification of malignant transformation in long-standing esophageal lye strictures or achalasia. All patients with newly diagnosed achalasia as a cause of dysphagia should have esophagogastroduodenoscopy to exclude the infiltrating gastric carcinoma which mimics achalasia. Esophagogastroduodenoscopy should also be performed periodically in established achalasia or when symptoms of achalasia change in order to exclude esophageal carcinoma. Dyspepsia or Ulcer Pain Dyspepsia or ulcer pain should initially be evaluated by x-ray examination. Classic duodenal ulcer or duodenal ulcer deformity with a compatible clinical history does not require endoscopy. However, in duodenal deformity with atypical pain, endoscopy should be performed to exclude concurrent gastric problems." Malignant appearing or indeterminate gastric ulcers should be confirmed by endoscopy prior to gastric surgery. Multiple biopsies at the ulcer margin and brush cytologic studies are reliable in preoperative diagnoses. Unnecessary surgery may be prevented and concurrent lesions identified. Endoscopic evaluation of radiographically benign gastric ulcers is controversial. In
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the Veterans Administration study, 3.3 per cent of radiographically benign ulcers were malignant. However, only 0.6 per cent of patients who passed the trial of healing had gastric carcinoma." Endoscopic evaluation of gastric ulcer is based upon gross appearance, multiple biopsies at the ulcer margin, and direct cytologic brushings." Many endoscopists will examine all gastric ulcers initially, and, if they are benign, follow at three to six week intervals with repeat biopsies until healing occurs. If healing is prolonged beyond 12 weeks then surgery is performed, except for giant gastric ulcers which may require more prolonged therapy. 28, 30
Abdominal Pain Abdominal pain or anemia that appears to be of upper gastrointestinal origin may not be diagnosed by upper gastrointestinal x-ray examination.s" Mucosal lesions of superficial, erosive, or atrophic gastritis often are identified only by esophagogastroduodenoscopy. Gastric ulcer, gastric polyps, or malignant tumors may be identified at gastroscopy. When the results of the upper gastrointestinal examination are negative, however, the decision to perform esophagogastroduodenoscopy depends upon the clinical nature and severity of the pain, and concurrent factors such as anemia, previous history of disease, and drug and alcohol use.
Upper Gastrointestinal Bleeding Chronic upper gastrointestinal bleeding may be evaluated by endoscopy for confirmation of radiographically demonstrated disease or detection of lesions not found radiographically. In acute gastrointestinal bleeding, esophagogastroduodenoscopy is more accurate than the conventional radiographic examination 17 when bleeding is caused by esophageal varices, gastric ulcer, or duodenal ulcer disease. Lesions such as erosive gastritis or Mallory-Weiss lacerations may be identified only by endoscopy. Radiography reveals only anatomical deformity and not necessarily the source of bleeding. Barium examination often interferes with subsequent endoscopy or arteriography if needed. 181 Which patients with acute gastrointestinal bleeding require esophagogastroduodenoscopy? How soon should it be done? Does it change the outcome? There are no firm answers to these commonly asked questions. Prior to emergency surgery, endoscopy can be useful in defining the site(s) of bleeding. Preoperative endoscopic identification permits a surgeon to perform selective rather than blind gastric resections. The surgical approach to severe erosive gastritis certainly varies from that of esophageal varices or duodenal ulcer. Such preoperative identification makes surgical treatment easier for the surgeon but may not be reflected in measurements of surgical mortality. Preferably, endoscopic evaluation is performed after blood volume replacement and initial stabilization. Gastric lavage allows for both estimation of the gross rate of bleeding and removal of blood clots prior to endoscopy. Endoscopic evaluation performed within 24 to 48 hours of admission re-
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veals a positive diagnosis 90 to 95 per cent of the time. 18 Delay in endoscopy beyond 48 hours decreases endoscopic identification to below 50 per cent." Does emergency endoscopy change either the morbidity or mortality resulting from acute gastrointestinal bleeding? Four controlled studies indicate that presently it probably does not. 10, 29 However, the identification of selective subsets of bleeding patients who receive specific benefit, and the development of therapeutic as well as diagnostic endoscopy may alter these results.
Postgastrectomy Symptoms Proper treatment of postgastrectomy syndromes require a proper diagnosis. Radiographic definition is the first important step in postoperative evaluation. Surgical distortion may make postoperative radiographic evaluation difficult or impossible in many instances. In addition, stomatitis, gastritis, and marginal ulceration are often seen only endoscopically. Patients with postgastrectomy complaints, particularly those suggesting mechanical or functional defects, should undergo 'endoscopic evaluation. 16
Therapeutic Endoscopy Specific therapeutic approaches for a variety of clinical indications are presently employed or under current investigation. Removal of foreign bodies from the esophagus or stomach is now common practice. Gastroscopic polypectomy prevents the need for surgical resection in many patients. Endoscopic direction of guidewires for Eder Puestow dilators in both malignant and benign strictures of the esophagus has become a useful approach. Celestine or other esophageal prosthesis may be inserted after dilatation over a pediatric endoscope under direct visualization or fluoroscopic guidance." Control of upper gastrointestinal bleeding is under active experimental and controlled clinical investigation." The role and indications still need to be defined. Work continues on refinement of the Argon and Neodinium-YAG laser, the heater probe, and electrocautery, but none of the current methods may now be recommended for routine clinical use.
INDICATIONS FOR ENDOSCOPIC RETROGRADE CHOLANGIOPANCREATOGRAPHY (ERCP) Since the successful cannulation of the ampulla of Vater was first described by McCune et al. in 1958,20 the procedure has gained wide acceptance to opacify the pancreatic and/or biliary tree. Skilled operators can cannulate 90 to 95 per cent of pancreatic ducts and 80 to 85 per cent of common bile ducts.": 28, 29 Cannulation of the common bile duct is facilitated in individuals with obstruction from common duct stones (92 per cent)." In over 8000 ERCP's surveyed, complications occurred in 3 per cent and death in 0.2 per cent of patients. Complications included pan-
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creatitis and cholangitis with sepsis. Death occurred in 15 instances from sepsis of pancreatic or biliary tract origin. 2 DIFFERENTIAL DIAGNOSIS OF JAUNDICE. When the cause of icterus is unclear ERCP or percutaneous transhepatic cholangiography (PTC) can be used to visualize the biliary tree. An algorithmic approach proposes that in patients with dilated ducts as determined by sonogram or computerized coaxial tomography PTC is the first choice, since with dilated ducts PTC is almost 100 per cent successful. When the ducts are not dilated, ERCP is done. If failure occurs the other procedure is done. In certain circumstances PTC is contraindicated and ERCP can be used (such as in presence of ascites, coagulopathy, etc.)." PATIENTS WITH SUSPECTED BILIARY TRACT DISEASE. ERCP is useful when patients are suspected of having stones or a stricture in the common bile duct especially after biliary tract surgery. ERCP also allows the unique opportunity of directly identifying a malignant tumor of the ampulla of Vater; choledochoduodenal anastomosis may be studied to determine whether it is patent or stenotic. PATIENTS WITH SUSPECTED PANCREATIC CARCINOMA. Pancreatography may strongly suggest the diagnosis of pancreatic carcinoma. 7 The most common radiographic features are the "cut-off" sign and a tapered stricture of the duct ("rat-tail" configuration). Ductal encasement or total obstruction occurs solely in carcinoma. To date ERCP has not contributed to early detection of cancer of the pancreas." A group of 70 patients suspected of having pancreatic carcinoma (typical abdominal pain, weight loss, or jaundice) prospectively underwent seven diagnostic tests. Thirty of these patients ultimately were proved to have cancer of the pancreas by surgery (28) or liver biopsy (2). Pancreatitis was found in seven, and nonpancreatic neoplasm in nine; in the remaining 24, either a benign disease was found or the examination was negative. For detection of pancreatic disease the most useful screening tests were those of pancreatic function, ultrasonography, and coaxial tomography. ERCP and arteriography were more sensitive and specific than the other modalities of diagnosis. Both of these were more sensitive than cytologic study in pancreatic cancer. These investigators had a single false negative ERCP in their group of 30 patients with cancer." Our personal experience would suggest that false negatives occur more frequently. In a different series, in 8 of 14 patients with pancreatic carcinoma positive cytologic findings were obtained from the pancreatic duct; they were equivocal in two patients and negative in one. These results were obtained by use of the washout saline technique." Percutaneous biopsy of pancreatic masses identified through sonography is gaining greater acceptance and may allow a definitive diagnosis in an otherwise infirm Individual.v' ERCP may also be used for this purpose. The aspiration needle can be guided to the area of the radiographically identified abnormality. This technique is remarkably safe. 14 PREOPERATIVE EVALUATION OF PANCREATITIS. When surgery in patients with chronic relapsing pancreatitis is being contemplated,
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ERCP may be useful in planning the operative procedure. ERCP can identify single or multiple strictures as well as pseudocysts. ERCP also allows postoperative assessment of a drainage procedure. 27 A pseudocyst of the pancreas ordinarily does not require ERCP, as there is a risk of creating a pancreatic abscess. Ultrasound is the diagnostic method of choice for pseudocysts.:" It has been reported that individuals with pancreatic ascites or pleural effusion of pancreatic origin uniformly exhibit extravasation of the injected contrast material into the peritoneal or pleural cavity suggesting rupture of the pancreatic ductal system. Surgical repair is frequently needed." THE RETAINED COMMON DUCT STONE. Ten to 15 per cent of patients operated on for gallstones have coincidental stones in the biliary tree;" Surgical treatment of these patients carries a mortality rate of 1.8 to 8.2 per cent, with older individuals being at even greater risk." With an average surgical mortality rate of about 5.2 per cent being widely quoted;" a nonoperative approach to these individuals would be ideal.
ENDOSCOPIC PAPILLOTOMY (EPT) Since 1975, German and Japanese authors have developed endoscopic papillotomy as an alternative method for those patients who have had their T-tubes removed from the common bile duct." Unfortunately, even in the most expert of hands this procedure is associated with substantial morbidity and mortality. This technique is acquiring slow acceptance in this country. Following endoscopic papillotomy, ERCP is routinely performed seven days later. If the stone(s) is still present, the incision may be enlarged or an attempt made to remove it with a Dormia basket or a balloon catheter. 5 In a recent paper, the results of 1100 EPT's were reviewed." In 63 per cent of the patients the stones passed spontaneously following EPT. In an additional 26 per cent of patients, the stones could be extracted by instrumental means. The European series has increased to more than 8000 patients." Proportional results have not changed. Stones larger than 3.0 em in diameter are no longer extracted. COMPLICATIONS. Ninety-four (8.5 per cent) of 1107 patients had complications such as pancreatitis, perforation, bleeding, cholangitis, and sepsis, which occurred when the stones became impacted in the distal common biliary duct resulting in ascending infection. The risk of this complication increases with the size of the stone." The mortality rate associated with EPT varies between 1 and 2 per cent."
INDICATIONS FOR COLONOSCOPY The fiberoptic colonoscope can be used to inspect the entire colon. Colonoscopy may detect lesions overlooked by radiography or routine sigmoidoscopy.
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Abnormal Radiographs STRICTURE OF THE COLON. Strictures of the colon warrant endoscopic evaluation. At times the strictures are artifactual and would therefore not require treatment. If a stricture is present, a determination can often be made regarding its benign or malignant nature." Inflammatory masses with stricturing may not allow adequate evaluation, especially when located within the sigmoid colon. The asymptomatic patient with a benign colonic stricture can be followed safely. An obvious malignant stricture does not require endoscopic evaluation. POLYPS. Most small colonic polyps are hyperplastic, are usually greater than 0.5 em in diameter, have a characteristic appearance, and do not carry a malignant potential. The other common epithelial polyps do. 29 We therefore recommend that polyps larger than 0.5 em be removed. It is not infrequent to identify other polyps not suspected at the time of radiography. Wolff and Shinya have reported the increased yield of colonoscopy compared with barium enema in detecting polyps." In a group of 500 patients with colorectal disease, an additional 118 polyps were identified, 21 of which were larger than 1 em in diameter. False positive findings were also reported; in 60 of 500 cases, no identifiable disease was evident upon colonoscopic examination. 3 9 Laufer et al. 19 reported that of 119 polyps diagnosed radiologically in 76 patients, only 56 were found on the initial endoscopic examination. Of the 16 polyps not found initially, five were found at repeat endoscopy, one polyp was identified at repeat radiology, six polyps could not be identified with repeat barium enema, and four patients were not followed. The missed lesions were located in areas of sharp angulation and therefore potential "blind" spots." Colonoscopic polypectomy is now a well accepted procedure. Most pedunculated polyps and some sessile polyps can be removed safely. Bleeding and perforation are the most common complications." CANCER OF THE COLON. The classic apple core lesion of a colonic carcinoma in most instances is so characteristic that further diagnostic definition is not required. The possibility of synchronous polyps or carcinoma requires endoscopic evaluation, however." Ten per cent of lesions thought to represent carcinomas on x-ray examination cannot be identified by colonoscopy of the area in question." INFLAMMATORY BOWEL DISEASE. Strictures seen on the radiographs of patients with inflammatory bowel disease require endoscopic evaluation and biopsy." The prognostic implications of the "precancerous" lesions of ulcerative colitis remain controversial. The vast majority of patients with inflammatory bowel disease involving the colon do not require colonoscopic examination. CHRONIC FECAL BLOOD Loss. Patients with positive stools for occult blood, whose samples have been collected for several days on a meat-free diet, and in whom the radiographic and proctoscopic workup is negative, require careful colonoscopic examination. Hunt et ale reported that in a group of 652 patients who had evidence of rectal bleeding and a negative work-up, 295 (45 per cent) had the causative
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lesion identified: 66 (10 per cent) had carcinomas, 136 polyps were removed, and 61 (9 per cent) had previously unidentified inflammatory bowel disease. A second group of patients had diverticulae seen on the radiographs; of these 10 per cent (15 patients) had carcinoma. In a group of 59 patients who were anemic, colonoscopy revealed carcinomas in 14 per cent (8 patients), with most being in the right colon. It is becoming increasingly clear that patients with colonic bleeding 'and a negative screening work-up should undergo pancolonoscopy.31.33 Angiodysplasias are common causes of recurrent bleeding; these lesions may be identified by the endoscopist as dilated submucosal vessels, usually in the right colon, that are seen to be oozing."? ACUTE RECTAL BLEEDING. Massive rectal bleeding may be caused by an upper or a lower gastrointestinal lesion. Massive colonic bleeding is best evaluated at present with angiography; the site of bleeding can be properly identified and frequently treated with vasopressin. The colonoscopist is hard-pressed under these circumstances to make accurate observations. After the bleeding has subsided and if the diagnosis remains unclear, barium enema or colonoscopy may be performed. FAMILIAL POLYPOSIS SYNDROMES. Colonoscopy detects some carriers of the dominant familial polyposis gene prior to barium enema and sigmoidoscopy. The above also applies to those affected with Gardner's syndrome." FLEXIBLE FIBEROPTIC SIGMOIDOSCOPY. Approximately 65 to 70 per cent of colonic carcinomas are located in the rectum, rectosigmoid junction, and sigmoid colon. Bohleman and Katon compared the yield of flexible sigmoidoscopy with that of rigid endoscopy in 139 patients." Significant lesions were discovered in 39 per cent of patients with the flexible instrument and in only 13 per cent with the rigid one. Usually (84 per cent of patients) the instrument had reached the descending colon." It is clear, however, that flexible sigmoidoscopy is not a substitute for barium enema or total colonoscopy and therefore the role of the flexible sigmoidoscope is controversial.
REFERENCES 1. Bilbao, M. K., Dotter, C. T., Ler, T. G., et al.: Complications of endoscopic retrograde cholangiopancreatography (ERCP). Gastroenterology, 70:314-320, 1976. 2. Blackstone, M. 0., Cockerham, L., Kirsner, J. B., et al.: Intraductal aspiration for Cyto diagnosis in pancreatic malignancy. Gastrointest. Endosc., 23 :145-47, 1977. 3. Bohlman, T. W., Kotow, R. M., et al.: Fiberoptic pansigmoidoscopy. An evaluation and comparison with rigid sigmoidoscopy. Gastroenterology, 72:644--649, 1977. 4. Cameron, J. L.: Chronic pancreatic ascites and pancreatic pleural effusion. Gastroenterology, 74 :134-140, 1978. 5. Classen, M., and Ossenberg, F. W.: Progress Report: Non-surgical removal of common bile duct stones. Gut, 18 :760-769, 1977. 6. Colcher, H: Current concepts in gastrointestinal endoscopy. New Engl. J. Med., 293 :22:1129-1131, 1975. 7. Cotton, P. B.: ERCP progress report. Gut, 1977 (provisional number 9A). 8. Dean, A. C. B., and Newell, J. P.: Colonoscopy in the differential diagnosis of carcinoma from diverticulitis of the sigmoid colon. Brit. J. Surg., 60 :633-35, 1973. 9. DiMagno, E., Malagelada, J. R., Taylor, W. F., et al.: A prospective comparison of current diagnostic tests for pancreatic cancer. New Engl. J. Med., 297 :737-742, 1977.
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10. Eastwood, G. L.: Does early endoscopy benefit the patient with active upper gastrointestinal bleeding? Gastroenterology, 72 :737-39, 1977. 11. Ekelund, G. R., and Pihl, B.: Multiple carcinomas of the colon and rectum. Cancer, 33 :1630, 1974. 12. Farid, T., Des, F. M., and Berkowitz, J. M.: Value of colonoscopy in the investigation of inflammatory bowel disease. Gastrointest. Endosc., 66:681, 1974. 13. Geenen, J. E.: Personal Communication. 14. Goldstein, H. M., and Zorroza, J. M.: Percutaneous transperitoneal aspiration biopsy of pancreatic masses. Am. J. Dig. Dis., 23 :840-843, 1978. 15. Hirschowitz, B. I., Curtiss, L. E., and Peters, C. W.: Demonstration of a new gastroscope, the fiberscope. Gastroenterology, 35 :50-53, 1958. 16. Hirschowitz, B. I., and Luketic, G. C.: Endoscopy in the post gastrectomy patient. Gastrointest. Endosc., 18:1 :27-30, 1971. 17. Keller, R. T., and Logan, G. M., Jr.: Comparison of emergent endoscopy and upper gastrointestinal series in acute upper gastrointestinal haemorrhage. Gut, 17: 180-184,1976. 18. Kotow, R. M., and Katon, R. M.: The pansigmoidoscope. One year experience in a gastrointestinal diagnostic unit. J. Clin. Gastroenterol., 1 :41-45, 1979. 19. Laufer, I., Smith, N. C. W., and Mullins, J. E.: The radiological demonstration of colorectal polyps. Gastroenterology, 70: 167-170, 1976. 20. McCune, W. S., Shorts, P. E., and Moscowitz, H.: Endoscopic cannulation of the ampulla of vater, a preliminary report. Am. J. Surg., 167:752,1958. 21. Pavlides, G. P., Milligan, F. D., Clark, D. N., et al.: Hereditary polyposes coli. The diagnostic value of colonoscopy, barium enema and fecal occult blood. Cancer, 40: 2632-2639, 1977. 22. Protell, R.: Laser photocoagulation for gastrointestinal bleeding. Clin. Gastroenterol., 7:765-774, 1978. 23. Rubin, C. E., Silverstein, F. E., and McDonald, G. B.: Indications for fiberoptic endoscopy. Viewpoints Dig. Dis., 10:2, 1978. 24. Safrany, L.: Duodenoscopic sphincterotomy and gallstone removal. Gastroenterology, 72:338, 1977. 25. Schiller, K. F. R. (ed.): Endoscopy. Clin. Gastroenterol., 7:552-798, 1978. 26. Schuman, B. M.: The gastroscope Yield from the negative upper gastrointestinal series. Gastrointest. Endosc., 19:79-80, 1972. 27. Schuman, B. M., Wong, K. H., Salimi, R., et al.: Endoscopic retrograde cholangiopancreatography at Henry Ford Hospital 1972-1977. HFH Med. J., 26:4,6,1978. 28. Silverstein, F. E., and Rubin, C. E.: The new look into the gastrointestinal tract. Disease of the Month, 23:5-12,1976. 29. Silverstein, F. E., Rubin, C. E., and McDonald, G. B.: Indications for fiberoptic endoscopy. Viewpoints Dig. Dis., 10:5, 1978. 30. Sleisenger, M., and Fordham, J.: Gastrointestinal Disease. Pathophysiology-DiagnosisTreatment.Edition 2. Philadelphia, W. B. Saunders Co., 1978. 31. Teague, R. H., Thornton, J. R., Manning, A. P., et al.: Colonoscopy for investigation of unexplained rectal bleeding. Lancet, 1 :1350-51, 1978. 32. Tedesco, F. J.: Role of gastroscope in gastric ulcer patients - Planning a prospective study. Gastroenterology, 73 :170-73, 1977. 33. Tedesco, F. J., Waye, J. D., et al.: Colonoscopic evaluation of rectal bleeding. Ann. Intern. Med., 89:907-910, 1979. 34. Vermes, J. A., Jacobson, J. R., and Silvis, J. E.: Endoscopic cholangiography for biliary system diagnosis. An. Intern. Med., 80:61-64, 1974. 35. Way, L.: Common duct stone. SURG. CLIN. NORTH AM., 53:1139-1147. 36. Weinstein, W. M.: Gastroscopy for gastric ulcer. Gastroenterology, 73: 1160-62, 1977. 37. Wolff, W. I. Grossman, M. B., et al.: Angiodysphasia of the colon. Diagnosis and treatment. Gastroenterology, 72:329-333,1977. 38. Wolff, W. I., and Shinya, H.: Earlier diagnosis of cancer of the colon through colonic endoscopy (colonoscopy). Cancer, 34 :912-931, 1974. 39. Wolff, W. I., Shinya, H. et al.: Comparison of colonoscopy and the contrast enema in 500 patients with colorectal disease. Am. J. Surg., 129:181-186, 1975. 40. Wolff, W. I., et al.: Polypectomy via fiberoptic colonoscope. Removal of neoplasms beyond the reach of the sigmoidscope. New Engl. J. Med., 329-337, 1973. Division of Gastroenterology Scott and White Clinic Temple, Texas 76501
Gastrointestinal Fiberoptic Endoscopy Diagnostic and Therapeutic Aspects
Thomas R. Liebermann, M.D., and Maurice Barnes, M.D.
Fiberoptic endoscopy has revolutionized the clinical practice of gastroenterology since its introduction by Hirschowitz et ale in 1958. 15 The esophagus, stomach, duodenum, and colon, as well as the pancreatic and biliary tree, may now be examined. The flexibility of these instruments allows a direct and relatively comfortable inspection of most of these structures. Most instruments are equipped with biopsy and brush cytologic capabilities. A variety of devices can be introduced through the biopsy channel including forceps for removal of foreign objects, electrocauteries, and snare devices. The use of these implements in therapy is increasing. The success of colonoscopic polypectomy has led to the development of other therapeutic modalities. However, increasing invasiveness has led to an expected increase in accidents resulting from the procedures. The importance of an expert performing these procedures cannot be overemphasized. Also, the correct interpretation of findings and safety are closely linked to the expertise of the individual doing the examination.
INDICATIONS FOR ESOPHAGOGASTRODUODENOSCOPY Esophagogastroduodenoscopy has evolved as an important diagnostic and potential therapeutic tool for many gastrointestinal diseases. Present technology enables the endoscopist to examine the esophagus, stomach, and first and second portion of the duodenum. There is still no consensus regarding indications for the procedure; however, certain guidelines may be given. From the Division of Gastroenterology, Scott and White Clinic, Temple, Texas
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Esophageal Symptoms Esophageal symptoms often require esophagogastroduodenoscopy for follow-up of radiographic findings, initial diagnosis, or institution of therapy. Dysphagia (difficulty in swallowing) or odynophagia (painful swallowing) are common symptoms for a variety of clinical disorders and require esophagogastroduodenoscopy for full evaluation. Esophageal strictures identified by barium swallow studies require esophagogastroduodenoscopy for further definition regarding benign or malignant origin. Endoscopically direct biopsies can diagnose in excess of 80 per cent of malignant strictures. The addition of brush cytology raises endoscopic identification of malignant strictures to more than 95 per cent." 25, 28 A substantial number of strictures that may be missed on barium swallow examination will be identified by endoscopy. Because it produces little or no change in mucosal silhouette, esophagitis cannot be diagnosed by barium swallow examination. Bleeding erosive esophagitis is clearly visible at endoscopy. Less severe esophagitis will be visible as only superficial erythema with friability or nodularity. Symptomatic patients with mild or healing esophagitis may have normal endoscopic findings and require either suction biopsy to demonstrate basal hyperplasia or other diagnostic tests for esophagitis." Odynophagia produced by herpes or monilia in immunosuppressed or host-compromised patients may be visualized by esophagogastroduodenoscopy, .with the use of a biopsy specimen and cytologic brushings for culture and cell Identification.": 25 Demonstration of Barrett's esophagus and its metaplasia to gastric mucosa replacing esophageal squamous mucosa may be demonstrated by esophagogastroduodenoscopy and confirmed by biopsy. Because of its premalignant potential, Barrett's mucosa should be followed at yearly intervals by esophagogastroduodenoscopy. Esophagogastroduodenoscopy is also useful for identification of malignant transformation in long-standing esophageal lye strictures or achalasia. All patients with newly diagnosed achalasia as a cause of dysphagia should have esophagogastroduodenoscopy to exclude the infiltrating gastric carcinoma which mimics achalasia. Esophagogastroduodenoscopy should also be performed periodically in established achalasia or when symptoms of achalasia change in order to exclude esophageal carcinoma. Dyspepsia or Ulcer Pain Dyspepsia or ulcer pain should initially be evaluated by x-ray examination. Classic duodenal ulcer or duodenal ulcer deformity with a compatible clinical history does not require endoscopy. However, in duodenal deformity with atypical pain, endoscopy should be performed to exclude concurrent gastric problems." Malignant appearing or indeterminate gastric ulcers should be confirmed by endoscopy prior to gastric surgery. Multiple biopsies at the ulcer margin and brush cytologic studies are reliable in preoperative diagnoses. Unnecessary surgery may be prevented and concurrent lesions identified. Endoscopic evaluation of radiographically benign gastric ulcers is controversial. In
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the Veterans Administration study, 3.3 per cent of radiographically benign ulcers were malignant. However, only 0.6 per cent of patients who passed the trial of healing had gastric carcinoma." Endoscopic evaluation of gastric ulcer is based upon gross appearance, multiple biopsies at the ulcer margin, and direct cytologic brushings." Many endoscopists will examine all gastric ulcers initially, and, if they are benign, follow at three to six week intervals with repeat biopsies until healing occurs. If healing is prolonged beyond 12 weeks then surgery is performed, except for giant gastric ulcers which may require more prolonged therapy. 28, 30
Abdominal Pain Abdominal pain or anemia that appears to be of upper gastrointestinal origin may not be diagnosed by upper gastrointestinal x-ray examination.s" Mucosal lesions of superficial, erosive, or atrophic gastritis often are identified only by esophagogastroduodenoscopy. Gastric ulcer, gastric polyps, or malignant tumors may be identified at gastroscopy. When the results of the upper gastrointestinal examination are negative, however, the decision to perform esophagogastroduodenoscopy depends upon the clinical nature and severity of the pain, and concurrent factors such as anemia, previous history of disease, and drug and alcohol use.
Upper Gastrointestinal Bleeding Chronic upper gastrointestinal bleeding may be evaluated by endoscopy for confirmation of radiographically demonstrated disease or detection of lesions not found radiographically. In acute gastrointestinal bleeding, esophagogastroduodenoscopy is more accurate than the conventional radiographic examination 17 when bleeding is caused by esophageal varices, gastric ulcer, or duodenal ulcer disease. Lesions such as erosive gastritis or Mallory-Weiss lacerations may be identified only by endoscopy. Radiography reveals only anatomical deformity and not necessarily the source of bleeding. Barium examination often interferes with subsequent endoscopy or arteriography if needed. 181 Which patients with acute gastrointestinal bleeding require esophagogastroduodenoscopy? How soon should it be done? Does it change the outcome? There are no firm answers to these commonly asked questions. Prior to emergency surgery, endoscopy can be useful in defining the site(s) of bleeding. Preoperative endoscopic identification permits a surgeon to perform selective rather than blind gastric resections. The surgical approach to severe erosive gastritis certainly varies from that of esophageal varices or duodenal ulcer. Such preoperative identification makes surgical treatment easier for the surgeon but may not be reflected in measurements of surgical mortality. Preferably, endoscopic evaluation is performed after blood volume replacement and initial stabilization. Gastric lavage allows for both estimation of the gross rate of bleeding and removal of blood clots prior to endoscopy. Endoscopic evaluation performed within 24 to 48 hours of admission re-
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veals a positive diagnosis 90 to 95 per cent of the time. 18 Delay in endoscopy beyond 48 hours decreases endoscopic identification to below 50 per cent." Does emergency endoscopy change either the morbidity or mortality resulting from acute gastrointestinal bleeding? Four controlled studies indicate that presently it probably does not. 10, 29 However, the identification of selective subsets of bleeding patients who receive specific benefit, and the development of therapeutic as well as diagnostic endoscopy may alter these results.
Postgastrectomy Symptoms Proper treatment of postgastrectomy syndromes require a proper diagnosis. Radiographic definition is the first important step in postoperative evaluation. Surgical distortion may make postoperative radiographic evaluation difficult or impossible in many instances. In addition, stomatitis, gastritis, and marginal ulceration are often seen only endoscopically. Patients with postgastrectomy complaints, particularly those suggesting mechanical or functional defects, should undergo 'endoscopic evaluation. 16
Therapeutic Endoscopy Specific therapeutic approaches for a variety of clinical indications are presently employed or under current investigation. Removal of foreign bodies from the esophagus or stomach is now common practice. Gastroscopic polypectomy prevents the need for surgical resection in many patients. Endoscopic direction of guidewires for Eder Puestow dilators in both malignant and benign strictures of the esophagus has become a useful approach. Celestine or other esophageal prosthesis may be inserted after dilatation over a pediatric endoscope under direct visualization or fluoroscopic guidance." Control of upper gastrointestinal bleeding is under active experimental and controlled clinical investigation." The role and indications still need to be defined. Work continues on refinement of the Argon and Neodinium-YAG laser, the heater probe, and electrocautery, but none of the current methods may now be recommended for routine clinical use.
INDICATIONS FOR ENDOSCOPIC RETROGRADE CHOLANGIOPANCREATOGRAPHY (ERCP) Since the successful cannulation of the ampulla of Vater was first described by McCune et al. in 1958,20 the procedure has gained wide acceptance to opacify the pancreatic and/or biliary tree. Skilled operators can cannulate 90 to 95 per cent of pancreatic ducts and 80 to 85 per cent of common bile ducts.": 28, 29 Cannulation of the common bile duct is facilitated in individuals with obstruction from common duct stones (92 per cent)." In over 8000 ERCP's surveyed, complications occurred in 3 per cent and death in 0.2 per cent of patients. Complications included pan-
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creatitis and cholangitis with sepsis. Death occurred in 15 instances from sepsis of pancreatic or biliary tract origin. 2 DIFFERENTIAL DIAGNOSIS OF JAUNDICE. When the cause of icterus is unclear ERCP or percutaneous transhepatic cholangiography (PTC) can be used to visualize the biliary tree. An algorithmic approach proposes that in patients with dilated ducts as determined by sonogram or computerized coaxial tomography PTC is the first choice, since with dilated ducts PTC is almost 100 per cent successful. When the ducts are not dilated, ERCP is done. If failure occurs the other procedure is done. In certain circumstances PTC is contraindicated and ERCP can be used (such as in presence of ascites, coagulopathy, etc.)." PATIENTS WITH SUSPECTED BILIARY TRACT DISEASE. ERCP is useful when patients are suspected of having stones or a stricture in the common bile duct especially after biliary tract surgery. ERCP also allows the unique opportunity of directly identifying a malignant tumor of the ampulla of Vater; choledochoduodenal anastomosis may be studied to determine whether it is patent or stenotic. PATIENTS WITH SUSPECTED PANCREATIC CARCINOMA. Pancreatography may strongly suggest the diagnosis of pancreatic carcinoma. 7 The most common radiographic features are the "cut-off" sign and a tapered stricture of the duct ("rat-tail" configuration). Ductal encasement or total obstruction occurs solely in carcinoma. To date ERCP has not contributed to early detection of cancer of the pancreas." A group of 70 patients suspected of having pancreatic carcinoma (typical abdominal pain, weight loss, or jaundice) prospectively underwent seven diagnostic tests. Thirty of these patients ultimately were proved to have cancer of the pancreas by surgery (28) or liver biopsy (2). Pancreatitis was found in seven, and nonpancreatic neoplasm in nine; in the remaining 24, either a benign disease was found or the examination was negative. For detection of pancreatic disease the most useful screening tests were those of pancreatic function, ultrasonography, and coaxial tomography. ERCP and arteriography were more sensitive and specific than the other modalities of diagnosis. Both of these were more sensitive than cytologic study in pancreatic cancer. These investigators had a single false negative ERCP in their group of 30 patients with cancer." Our personal experience would suggest that false negatives occur more frequently. In a different series, in 8 of 14 patients with pancreatic carcinoma positive cytologic findings were obtained from the pancreatic duct; they were equivocal in two patients and negative in one. These results were obtained by use of the washout saline technique." Percutaneous biopsy of pancreatic masses identified through sonography is gaining greater acceptance and may allow a definitive diagnosis in an otherwise infirm Individual.v' ERCP may also be used for this purpose. The aspiration needle can be guided to the area of the radiographically identified abnormality. This technique is remarkably safe. 14 PREOPERATIVE EVALUATION OF PANCREATITIS. When surgery in patients with chronic relapsing pancreatitis is being contemplated,
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ERCP may be useful in planning the operative procedure. ERCP can identify single or multiple strictures as well as pseudocysts. ERCP also allows postoperative assessment of a drainage procedure. 27 A pseudocyst of the pancreas ordinarily does not require ERCP, as there is a risk of creating a pancreatic abscess. Ultrasound is the diagnostic method of choice for pseudocysts.:" It has been reported that individuals with pancreatic ascites or pleural effusion of pancreatic origin uniformly exhibit extravasation of the injected contrast material into the peritoneal or pleural cavity suggesting rupture of the pancreatic ductal system. Surgical repair is frequently needed." THE RETAINED COMMON DUCT STONE. Ten to 15 per cent of patients operated on for gallstones have coincidental stones in the biliary tree;" Surgical treatment of these patients carries a mortality rate of 1.8 to 8.2 per cent, with older individuals being at even greater risk." With an average surgical mortality rate of about 5.2 per cent being widely quoted;" a nonoperative approach to these individuals would be ideal.
ENDOSCOPIC PAPILLOTOMY (EPT) Since 1975, German and Japanese authors have developed endoscopic papillotomy as an alternative method for those patients who have had their T-tubes removed from the common bile duct." Unfortunately, even in the most expert of hands this procedure is associated with substantial morbidity and mortality. This technique is acquiring slow acceptance in this country. Following endoscopic papillotomy, ERCP is routinely performed seven days later. If the stone(s) is still present, the incision may be enlarged or an attempt made to remove it with a Dormia basket or a balloon catheter. 5 In a recent paper, the results of 1100 EPT's were reviewed." In 63 per cent of the patients the stones passed spontaneously following EPT. In an additional 26 per cent of patients, the stones could be extracted by instrumental means. The European series has increased to more than 8000 patients." Proportional results have not changed. Stones larger than 3.0 em in diameter are no longer extracted. COMPLICATIONS. Ninety-four (8.5 per cent) of 1107 patients had complications such as pancreatitis, perforation, bleeding, cholangitis, and sepsis, which occurred when the stones became impacted in the distal common biliary duct resulting in ascending infection. The risk of this complication increases with the size of the stone." The mortality rate associated with EPT varies between 1 and 2 per cent."
INDICATIONS FOR COLONOSCOPY The fiberoptic colonoscope can be used to inspect the entire colon. Colonoscopy may detect lesions overlooked by radiography or routine sigmoidoscopy.
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Abnormal Radiographs STRICTURE OF THE COLON. Strictures of the colon warrant endoscopic evaluation. At times the strictures are artifactual and would therefore not require treatment. If a stricture is present, a determination can often be made regarding its benign or malignant nature." Inflammatory masses with stricturing may not allow adequate evaluation, especially when located within the sigmoid colon. The asymptomatic patient with a benign colonic stricture can be followed safely. An obvious malignant stricture does not require endoscopic evaluation. POLYPS. Most small colonic polyps are hyperplastic, are usually greater than 0.5 em in diameter, have a characteristic appearance, and do not carry a malignant potential. The other common epithelial polyps do. 29 We therefore recommend that polyps larger than 0.5 em be removed. It is not infrequent to identify other polyps not suspected at the time of radiography. Wolff and Shinya have reported the increased yield of colonoscopy compared with barium enema in detecting polyps." In a group of 500 patients with colorectal disease, an additional 118 polyps were identified, 21 of which were larger than 1 em in diameter. False positive findings were also reported; in 60 of 500 cases, no identifiable disease was evident upon colonoscopic examination. 3 9 Laufer et al. 19 reported that of 119 polyps diagnosed radiologically in 76 patients, only 56 were found on the initial endoscopic examination. Of the 16 polyps not found initially, five were found at repeat endoscopy, one polyp was identified at repeat radiology, six polyps could not be identified with repeat barium enema, and four patients were not followed. The missed lesions were located in areas of sharp angulation and therefore potential "blind" spots." Colonoscopic polypectomy is now a well accepted procedure. Most pedunculated polyps and some sessile polyps can be removed safely. Bleeding and perforation are the most common complications." CANCER OF THE COLON. The classic apple core lesion of a colonic carcinoma in most instances is so characteristic that further diagnostic definition is not required. The possibility of synchronous polyps or carcinoma requires endoscopic evaluation, however." Ten per cent of lesions thought to represent carcinomas on x-ray examination cannot be identified by colonoscopy of the area in question." INFLAMMATORY BOWEL DISEASE. Strictures seen on the radiographs of patients with inflammatory bowel disease require endoscopic evaluation and biopsy." The prognostic implications of the "precancerous" lesions of ulcerative colitis remain controversial. The vast majority of patients with inflammatory bowel disease involving the colon do not require colonoscopic examination. CHRONIC FECAL BLOOD Loss. Patients with positive stools for occult blood, whose samples have been collected for several days on a meat-free diet, and in whom the radiographic and proctoscopic workup is negative, require careful colonoscopic examination. Hunt et ale reported that in a group of 652 patients who had evidence of rectal bleeding and a negative work-up, 295 (45 per cent) had the causative
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lesion identified: 66 (10 per cent) had carcinomas, 136 polyps were removed, and 61 (9 per cent) had previously unidentified inflammatory bowel disease. A second group of patients had diverticulae seen on the radiographs; of these 10 per cent (15 patients) had carcinoma. In a group of 59 patients who were anemic, colonoscopy revealed carcinomas in 14 per cent (8 patients), with most being in the right colon. It is becoming increasingly clear that patients with colonic bleeding 'and a negative screening work-up should undergo pancolonoscopy.31.33 Angiodysplasias are common causes of recurrent bleeding; these lesions may be identified by the endoscopist as dilated submucosal vessels, usually in the right colon, that are seen to be oozing."? ACUTE RECTAL BLEEDING. Massive rectal bleeding may be caused by an upper or a lower gastrointestinal lesion. Massive colonic bleeding is best evaluated at present with angiography; the site of bleeding can be properly identified and frequently treated with vasopressin. The colonoscopist is hard-pressed under these circumstances to make accurate observations. After the bleeding has subsided and if the diagnosis remains unclear, barium enema or colonoscopy may be performed. FAMILIAL POLYPOSIS SYNDROMES. Colonoscopy detects some carriers of the dominant familial polyposis gene prior to barium enema and sigmoidoscopy. The above also applies to those affected with Gardner's syndrome." FLEXIBLE FIBEROPTIC SIGMOIDOSCOPY. Approximately 65 to 70 per cent of colonic carcinomas are located in the rectum, rectosigmoid junction, and sigmoid colon. Bohleman and Katon compared the yield of flexible sigmoidoscopy with that of rigid endoscopy in 139 patients." Significant lesions were discovered in 39 per cent of patients with the flexible instrument and in only 13 per cent with the rigid one. Usually (84 per cent of patients) the instrument had reached the descending colon." It is clear, however, that flexible sigmoidoscopy is not a substitute for barium enema or total colonoscopy and therefore the role of the flexible sigmoidoscope is controversial.
REFERENCES 1. Bilbao, M. K., Dotter, C. T., Ler, T. G., et al.: Complications of endoscopic retrograde cholangiopancreatography (ERCP). Gastroenterology, 70:314-320, 1976. 2. Blackstone, M. 0., Cockerham, L., Kirsner, J. B., et al.: Intraductal aspiration for Cyto diagnosis in pancreatic malignancy. Gastrointest. Endosc., 23 :145-47, 1977. 3. Bohlman, T. W., Kotow, R. M., et al.: Fiberoptic pansigmoidoscopy. An evaluation and comparison with rigid sigmoidoscopy. Gastroenterology, 72:644--649, 1977. 4. Cameron, J. L.: Chronic pancreatic ascites and pancreatic pleural effusion. Gastroenterology, 74 :134-140, 1978. 5. Classen, M., and Ossenberg, F. W.: Progress Report: Non-surgical removal of common bile duct stones. Gut, 18 :760-769, 1977. 6. Colcher, H: Current concepts in gastrointestinal endoscopy. New Engl. J. Med., 293 :22:1129-1131, 1975. 7. Cotton, P. B.: ERCP progress report. Gut, 1977 (provisional number 9A). 8. Dean, A. C. B., and Newell, J. P.: Colonoscopy in the differential diagnosis of carcinoma from diverticulitis of the sigmoid colon. Brit. J. Surg., 60 :633-35, 1973. 9. DiMagno, E., Malagelada, J. R., Taylor, W. F., et al.: A prospective comparison of current diagnostic tests for pancreatic cancer. New Engl. J. Med., 297 :737-742, 1977.
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10. Eastwood, G. L.: Does early endoscopy benefit the patient with active upper gastrointestinal bleeding? Gastroenterology, 72 :737-39, 1977. 11. Ekelund, G. R., and Pihl, B.: Multiple carcinomas of the colon and rectum. Cancer, 33 :1630, 1974. 12. Farid, T., Des, F. M., and Berkowitz, J. M.: Value of colonoscopy in the investigation of inflammatory bowel disease. Gastrointest. Endosc., 66:681, 1974. 13. Geenen, J. E.: Personal Communication. 14. Goldstein, H. M., and Zorroza, J. M.: Percutaneous transperitoneal aspiration biopsy of pancreatic masses. Am. J. Dig. Dis., 23 :840-843, 1978. 15. Hirschowitz, B. I., Curtiss, L. E., and Peters, C. W.: Demonstration of a new gastroscope, the fiberscope. Gastroenterology, 35 :50-53, 1958. 16. Hirschowitz, B. I., and Luketic, G. C.: Endoscopy in the post gastrectomy patient. Gastrointest. Endosc., 18:1 :27-30, 1971. 17. Keller, R. T., and Logan, G. M., Jr.: Comparison of emergent endoscopy and upper gastrointestinal series in acute upper gastrointestinal haemorrhage. Gut, 17: 180-184,1976. 18. Kotow, R. M., and Katon, R. M.: The pansigmoidoscope. One year experience in a gastrointestinal diagnostic unit. J. Clin. Gastroenterol., 1 :41-45, 1979. 19. Laufer, I., Smith, N. C. W., and Mullins, J. E.: The radiological demonstration of colorectal polyps. Gastroenterology, 70: 167-170, 1976. 20. McCune, W. S., Shorts, P. E., and Moscowitz, H.: Endoscopic cannulation of the ampulla of vater, a preliminary report. Am. J. Surg., 167:752,1958. 21. Pavlides, G. P., Milligan, F. D., Clark, D. N., et al.: Hereditary polyposes coli. The diagnostic value of colonoscopy, barium enema and fecal occult blood. Cancer, 40: 2632-2639, 1977. 22. Protell, R.: Laser photocoagulation for gastrointestinal bleeding. Clin. Gastroenterol., 7:765-774, 1978. 23. Rubin, C. E., Silverstein, F. E., and McDonald, G. B.: Indications for fiberoptic endoscopy. Viewpoints Dig. Dis., 10:2, 1978. 24. Safrany, L.: Duodenoscopic sphincterotomy and gallstone removal. Gastroenterology, 72:338, 1977. 25. Schiller, K. F. R. (ed.): Endoscopy. Clin. Gastroenterol., 7:552-798, 1978. 26. Schuman, B. M.: The gastroscope Yield from the negative upper gastrointestinal series. Gastrointest. Endosc., 19:79-80, 1972. 27. Schuman, B. M., Wong, K. H., Salimi, R., et al.: Endoscopic retrograde cholangiopancreatography at Henry Ford Hospital 1972-1977. HFH Med. J., 26:4,6,1978. 28. Silverstein, F. E., and Rubin, C. E.: The new look into the gastrointestinal tract. Disease of the Month, 23:5-12,1976. 29. Silverstein, F. E., Rubin, C. E., and McDonald, G. B.: Indications for fiberoptic endoscopy. Viewpoints Dig. Dis., 10:5, 1978. 30. Sleisenger, M., and Fordham, J.: Gastrointestinal Disease. Pathophysiology-DiagnosisTreatment.Edition 2. Philadelphia, W. B. Saunders Co., 1978. 31. Teague, R. H., Thornton, J. R., Manning, A. P., et al.: Colonoscopy for investigation of unexplained rectal bleeding. Lancet, 1 :1350-51, 1978. 32. Tedesco, F. J.: Role of gastroscope in gastric ulcer patients - Planning a prospective study. Gastroenterology, 73 :170-73, 1977. 33. Tedesco, F. J., Waye, J. D., et al.: Colonoscopic evaluation of rectal bleeding. Ann. Intern. Med., 89:907-910, 1979. 34. Vermes, J. A., Jacobson, J. R., and Silvis, J. E.: Endoscopic cholangiography for biliary system diagnosis. An. Intern. Med., 80:61-64, 1974. 35. Way, L.: Common duct stone. SURG. CLIN. NORTH AM., 53:1139-1147. 36. Weinstein, W. M.: Gastroscopy for gastric ulcer. Gastroenterology, 73: 1160-62, 1977. 37. Wolff, W. I. Grossman, M. B., et al.: Angiodysphasia of the colon. Diagnosis and treatment. Gastroenterology, 72:329-333,1977. 38. Wolff, W. I., and Shinya, H.: Earlier diagnosis of cancer of the colon through colonic endoscopy (colonoscopy). Cancer, 34 :912-931, 1974. 39. Wolff, W. I., Shinya, H. et al.: Comparison of colonoscopy and the contrast enema in 500 patients with colorectal disease. Am. J. Surg., 129:181-186, 1975. 40. Wolff, W. I., et al.: Polypectomy via fiberoptic colonoscope. Removal of neoplasms beyond the reach of the sigmoidscope. New Engl. J. Med., 329-337, 1973. Division of Gastroenterology Scott and White Clinic Temple, Texas 76501
