Letter Colonoscopy In his article entitled "Colorectal Cancer: The Case for Barium Enema," published in the March 1992 issue of the Mayo Clinic Proceedings (pages 253 to 257), Dr. MacCarty states: "A major limitation of colonoscopy is that the cecum cannot be visualized in 10 to 36% of cases." To support his statement, Dr. MacCarty cites four studies, none more recent than 1984 and two of which are only abstracts. We consider his statement inaccurate and unrepresentative of modem experience. To obtain an accurate percentage of the visualization rate of the cecum for colonoscopy in the 1990s, we retrospectively reviewed our own experience with colonoscopy during the past 12 months. We performed a total of 430 colonoscopies, none of which was excluded from review. All procedures were done by first- and second-year fellows in gastroenterology under the direct supervision of one of us. A 135-cm or 165-cm Olympus EVIS 100 videocolonoscope or a 165-cm Olympus CF X20 pediatric colonoscope fitted with a video adapter was used for all examinations. Fluoroscopy was not used. For purposes of our review, the cecum was considered reached if the endoscopy report included a description of visualized cecal landmarks (for example, appendiceal orifice, ileocecal valve, and terminal ileum) and if electronic images confirmed these landmarks. The cecum was surgically absent in 12 of our cases; thus, 418 cases were available for analysis. In 17 cases (4%), the cecum was not visualized; therefore, the success rate in visualizing the cecum was 96%. In 11 of the 17 instances of incomplete examination, the reason was either an obstructive malignant lesion (6 cases) or failure in an emergent situation because of acute bleeding in the gastrointestinal tract or attempted colonic decompression for pseudo-obstruction (5 cases). If these failures are excluded, the overall failure rate was 1.5%, and the success rate was 98.5%. Our experience is comparable to that of Waye and Bashkoff,' who reported a 95.9% visualization rate of the cecum. When they excluded the cases of obstructing lesions from analysis, their success rate was 98%. Our results and those of Waye and Bashkoff confirm that the technical success rate of modem colonoscopy exceeds 95% when performed by competent gastroenterologists. Because of the improvements in colonoscopy equipment, techniques, and training, the technical success rates derived from experiences more than a few years ago are obsolete. Failure to visualize the cecum during colonoscopy can no longer be Mayo Clin Proc 67:1120,1992

considered a limitation of this procedure. The high success rate of colonoscopy, its unsurpassed diagnostic accuracy, and its therapeutic applications have substantially improved the ability of gastroenterologists to diagnose and manage colonic polyps. James S. Barthel, M.D. Director, Endoscopy Center John B. Marshall, M.D. Interim Director, Division of Gastroenterology University of Missouri-Columbia Columbia, Missouri

REFERENCE

1. Waye JD, Bashkoff E: Total colonoscopy: is it always pos-

sible? Gastrointest Endosc 37:152-154, 1991

Dr. MacCarty replies Drs. Barthel and Marshall are certainly correct in saying that, because of improvements in equipment, technique, and training, expert gastroenterologists and trainees under expert supervision reportedly reach the cecum in a high percentage of colonoscopies. The recent experience of gastroenterologists and fellows at the Mayo Clinic indicates a success rate of 93% (Ahlquist DA: Personal communication), which is consistent with that of Drs. Barthel and Marshall and Waye and Bashkoff.' Not all colonoscopists, however, are experts. Nongastroenterologists, gastroenterologists who were trained before the aforementioned technical improvements, and inexperienced colonoscopists who have recently completed training programs presumably perform a substantial number of colonoscopic procedures. Thus, the success rate in reaching the cecum will probably be considerably less than that achieved by Drs. Barthel and Marshall. Therefore, in my opinion, it is premature to conclude that "failure to visualize the cecum during colonoscopy can no longer be considered a limitation ...." Robert L. MacCarty, M.D.

REFERENCE

1. Waye JD, Bashkoff E: Total colonoscopy: is it always pos-

1120

sible? GastrointestEndosc 37:152-154,1991