ALIMENTARY TRACT FIBEROPTIC PANSIGMOIDOSCOPY. An evaluation and comparison with rigid sigmoidoscopy

Transcription

1 GASTROENTEROLOGY 72: , 1977 Copyright 1977 by The American Gastroenterological Association Vol. 72, No.4, Part 1 Printed in U.S.A. ALIMENTARY TRACT FIBEROPTIC PANSIGMOIDOSCOPY An evaluation and comparison with rigid sigmoidoscopy THEODORE W. BOHLMAN, M.D., RONALD M. KATON, M.D., GILBERT R. LIPSHUTZ, M.D., MICHAEL F. MCCOOL, M.D. FREDERICK W. SMITH, M.D., AND CLIFFORD S. MELNYK, M.D. Division of Gastroenterology, Department of Medicine, University of Oregon Health Sciences Center, and the United States Veterans Administration Hospital, Portland, Oregon A flexible 60-cm fiberoptic sigmoidoscope was evaluated in 139 patients'. In 120 patients flexible sigmoidoscopy was compared with routine rigid sigmoidoscopy with respect to patient tolerance, distance of inspection, procedure time, and diagnostic yield. All patients were prepared with a single cleansing enema, and given no analgesia. Despite the fact that the flexible i n s t r was u m inserted ~ n t nearly 3 times as far into the colon (55 cm versus 20 cm), more patients preferred the flexible examination. Significant pathological lesions were discovered by the flexible examination in 39% of patients, whereas rigid sigmoidoscopy discovered lesions in only 13%. Fluoroscopy performed during flexible sigmoidoscopy in 19 additional patients revealed that the instrument tip had reached the descending colon or beyond in 84% of patients. There were no complications. The flexible fiberoptic pansigmoidoscope offers promise as a practical diagnostic tool for a rapid and complete examination in patients with suspected colorectal diseases. Received June 28, Accepted September 28, Address requests for reprints to: Dr. Ronald M. Katon, 3181 Southwest Sam Jackson Park Road, Portland, Oregon The standard 25-cm rigid sigmoidoscope has been used in the evaluation of colorectal disease for decades. 1 In spite of its unquestioned value in the evaluation of patients with colonic problems, serious limitations in its diagnostic usefulness remain. The major deficiency of this instrument is that the average sigmoidoscopist inspects primarily the distal 15 to 18 cm of colon. 2 Diverticular disease, strictures, localized inflammatory bowel disease, polyps, and colon cancer often occur more proximally in the colon, just beyond the reach ofthe rigid instrument. Previous studies indicated that perhaps 70% of colon neoplasms were located in the distal 25 cm of bowel and should be seen by this instrument. 3 Recent data, however, suggest a major change in distribution, with a greater number oflesions above the level of the rectosigmoid.4, 5-10 Thus, the potential of finding colon cancer by rigid sigmoidoscopy alone may be diminishing. Additional problems with rigid sigmoidoscopy include unavoidable discomfort and difficulties in traversing the redundant lower sigmoid segment. These problems may lead the sigmoidoscopist to abandon the procedure before a thorough examination is accomplished. There is a need for an instrument which would allow an expedient and more extensive examination ofthe lower colon with less patient discomfort. Newer flexible fiberoptic instruments have this potential. Salmon and his group were the first to report their experience with such an instrument. 7 They used an Olympus 86-cm flexible sigmoidoscope (Olympus Company of America, New Hyde Park, N. Y.) with twodirectional tip control in the investigation of 51 patients with large bowel disease. Although their studies showed superior diagnostic yield with such an instrument, the vigorous preparation and extensive analgesia required limited the usefulness of that instrument for routine screening examinations. Present day colonoscopes are of proven value in the diagnostic evaluation and treatment of patients with colorectal disease. We used a 100- cm MB colonoscope in a pilot study, comparing this instrument with rigid sigmoidoscopy in 75 patients. We demonstrated a marked increase in diagnostic yield with the flexible instrument. 9 However, the value of these instruments for routine use is limited by the necessity of preexamination sedation and analgesia, intensive bowel preparation, the cumbersome nature of the instrument, the inherent risks of the procedure, and the need for extensive training and experience to perform a complete colonoscopic examination. 6, 8 In the spring of 1975 we urged the Olympus Company of America to develop a flexible fiberoptic pansigmoidoscope. This instrument would ideally allow for a com- 644

2 April 1977 FIRER OPTIC PANSIGMOlDOSCOPY 645 plete rapid examination of the distal colon without the discomfort and inadequacies of the rigid sigmoidoscope or the problems and liabilities offull scale colonoscopy. In January of 1976 such a prototype instrument became available-the Olympus TCF-1S 60-cm fiberoptic sigmoidoscope. We performed a study comparing routine rigid sigmoidoscopy employing the standard 25-cm sigmoidoscope with fiberoptic pansigmoidoscopy using the Olympus prototype instrument. We were interested in comparing patient tolerance, colonic distance examined, and diagnostic yield with these two instruments. The purpose of this report is to describe the new instrument and present the results of this study. The Instrument The Olympus TCF-1S fiberoptic sigmoidoscope (fig. 1) is not just a shortened conventional colonoscope, but has several new features not incorporated in other fiberscopes. It has a working length of 60 cm. The diameter of the distal hood is 19 mm, and the proximal body diameter is 15.4 mm. The four-way controllable tip has a bending section which can be turned up and down and left and right, for a combined maximal angulation of Control knobs and valves for air and water insufflation are similar to those of previous model colonoscopes. The optics have been improved by a major change in the design of the image bundle fibers. These fibers are approximately 60% of the diameter used in previous model colonoscopes and provide a much brighter image. The instrument has one large 5-mm diameter suction biopsy channel. This allows for insertion of larger biopsy forceps (fig. 2). We evaluated a larger 3.5-mm outer diameter cup biopsy forceps which has coagulation biopsy ("hot biopsy") potential. This forceps has the capability of obtaining large tissue samples, 3.5 by 3.0 mm in diameter. The 5-mm channel also improves suction capabilities, making it possible to remove large quantities of liquid stool, mucus, or blood from the bowel lumen. FIG. 1. Operating head ofthe Olympus TCF-IS fiberoptic sigmoidoscope showing: (a) external suction tubing attachment, (b) large capacity suction valve, and (c) water jet valve apparatus. FIG. 2. Distal instrument tip illustrating: (a) large 5-mm suctionbiopsy channel, and (b) large 3.5-mm biopsy forceps. TABLE 1. Comparison of the suction capabilities of the TCF-1S sigmoidoscope and MR2 colonoscope Time Material aspirated TCF-1S ME' (60 em) 000 em) sec 500 ml water, free channel 500 ml water, biopsy forceps in channel 250 ml packed cells ml water (50:50 dilution), free channel 250 ml packed cells ml water (50:50 dilution), biopsy forceps in channel 500 ml packed cells, free channel 500 ml packed cells, biopsy forceps in channel The suction valve is a spring-loaded turret located on the upper proximal part of the control head. External suction tubing connects directly from the suction pump to this suction valve. The suction apparatus thus bypasses the light source pigtail, making it easy to clear a plugged suction tube, and also contributing to the increased suction potential. We compared the suction ability of the Olympus TCF-1S sigmoidoscope with the Olympus MB-2 colonoscope (100 cm), measuring the time required to aspirate 500 ml of water and diluted, and nondiluted packed cells. A standard Gomco suction apparatus was used in this comparison. We evaluated suction capabilities of these instruments with and without a standard diameter biopsy forceps placed in the suction biopsy channel. The results of this comparison are shown in table 1. A separate water jet valve is also present in the control head. A water-filled syringe is attached to this valve, and water is squirted through this channel to clean stool and debris from the instrument tip and colon wall. Light sources used with the instrument are the conventional halogen and xenon models.

3 646 BOHLMAN ET AL. Vol. 72, No. 4, Part 1 Materials and Methods Patients who underwent rigid sigmoidoscopy in the Gastroenterology Diagnostic Unit at the University of Oregon Health Sciences Center or the Portland Veterans Administration Hospital from January 15th to May 15th, 1976 were entered into the study. One hundred and twenty unselected patients were evaluated. The indications for sigmoidoscopy were routine screening examination (37 patients), guaiac-positive stool (35 patients), rectal bleeding (17 patients), cancer screening in patients with extracolonic malignancy (14 patients), diarrhea (6 patients), abdominal pain (5 patients), suspected inflammatory bowel disease (4 patients), and sigmoid stricture (2 patients). The age range was 12 to 92 years, with a mean age of 52. The patients studied were brought to the Gastroenterology Diagnostic Unit having been prepared with a single Fleet or tap water enema. They were told that we were evaluating a new, longer, flexible sigmoidoscope which allowed for a more complete inspection of the lower bowel. The procedures and potential risks involved were explained to the patient and permission was obtained to perform both rigid and flexible sigmoidoscopy. Coagulation profiles were performed before the procedure in anticipation of possible biopsy or polypectomy. The patients were then placed on a Ritter table in the conventional inverted position and perianal inspection was done. Sigmoidoscopy was then performed sequentially with both instruments, alternating the order of the examination so as to avoid bias. In no case was sedation or analgesia used. Rigid sigmoidoscopy was performed by an experienced member of the house staff, gastroenterology fellow, or staff, and a flexible exam was performed by a gastroenterology fellow or staff. Both exams were performed with the aid of an assistant. In all but 2 cases (sigmoid stricture) there was no knowledge of barium enema findings. Both instruments were advanced to maximum distance or to patient tolerance and the following observations were made: (1) time required to advance the instrument to maximum distance; (2) time required for the entire examination; (3) the distance the instrument was advanced (measured in centimeters); (4) patient discomfort, graded as mild, moderate, and severe; (5) specific abnormalities identified and their location; (6) adequacy of preparation; (7) complications. There was no exchange of information regarding either examination until both operators had completed their examination and had recorded their observations. All mucosal abnormalities, polyps, or other lesions identified were biopsied. These were performed during the flexible exam only. In a few select cases polypectomy was performed, also with the flexible instrument. At the termination of both procedures the patients were questioned about the examinations. They were asked if they preferred one procedure over the other and if so, why? Specific comments were requested and recorded. The patients were then observed for a short period of time for possible complications. The results of both examinations were compared and analyzed. Fluoroscopy was performed during the examination on an additional 19 patients who were evaluated only with the flexible instrument. The purpose of this exam was to determine the actual anatomic location of the instrument tip when the instrument had been advanced to its full 60-cm length. Results The following represents a review of the findings. Quality of preparation. In most instances a single tap water enema or Fleet enema was given before the exam. Except in a small number of patients (10%), this was sufficient to cleanse the distal colon adequately to permit complete visualization. The small amount of liquid stool or mucus which remained could easily be removed by the large suction channel of the flexible instrument. The few patients who had firm stool remaining were given a second Fleet enema, to permit complete evacuation. In no patient was the study abandoned because of inadequate preparation. Time required for the examination. The times required to perform the examination with both instruments were recorded and reported to the nearest 1/2 min. Two end points were observed: (1) the time required to advance the instrument to maximum length, and (2) the time necessary to complete the entire exam. The results are shown in table 2. There was no significant difference in the time required to insert either instrument to maximum distance (rigid 3.9 min, flexible 4.7 min). Flexible sigmoidoscopy was more time-consuming, if one compares the time required to complete the entire exam (rigid 5.9 min, flexible 9.4 min). The time period also includes all procedures - biopsy, polyectomy, and photography - which were performed solely with the flexible instrument, thus prolonging the average time required to complete the examination. Distance visualized. The maximum distance each instrument was inserted was observed and reported to the nearest centimeter. The rigid instrument was inserted an average distance of 20.4 cm, whereas the flexible instrument was inserted an average of 55 cm. The examiner was successful in advancing the flexible instrument to its full 60-cm length in 62% of the procedures, whereas the rigid instrument was successfully inserted to 25 cm in 35% of patients. The major reasons for failure to achieve maximal penetration with the flexible instrument were patient pain, obstructing lesions, acute angulation of sigmoid loop, strictures, and inadequate preparation. In no patient was less than 30 cm of colon inspected by the flexible instrument (table 2). In 19 additional patients, fluoroscopy was performed during the flexible examination to determine the exact anatomical location of the instrument tip. The results of this study are shown in table 3. We successfully reached the descending colon in 84% of patients studied. Figure 3 demonstrates the anatomic location of the rigid 'and flexible instruments when inserted to their maximum lengths in the same patient. Patient tolerance. At the termination of both examinations, patients were questioned regarding their com- TABLE 2. Results of the comparison Instrument Parameter evaluated Rigid No Flexible difference Time required to perform exam To maximum distance (min) To perform complete exam (min) Average distance advanced (cm) Patient preference (%)

4 April 1977 FIBER OPTIC PANSIGMOIDOSCOPY 647 fort and acceptance of the two procedures. Results of this questionaire are shown in table 2. Forty-three per cent of patients preferred or had less discomfort with the flexible instrument, whereas 33% preferred the rigid exam. Twenty-four per cent felt that there was no difference. Abnormalities found. The results are shown on table 4. Significant abnormalities were discovered on rigid sigmoidoscopy in 15 patients or 13% of those studied. In contrast, pertinent pathology was discovered with the flexible instrument in 47 patients or 39% of those patients examined. Thirty-two patients (or 27% of those studied) had some abnormality discovered with the flexible instrument which was not seen by rigid sigmoidoscopy. Of these 32 patients 17 had 26 polyps (24 benign, 2 malignant) which the rigid instrument had not detected. Ten of these polyps were 2 to 4 mm in diameter, 11 were 5 mm to 1 cm in diameter, and 5 were larger than 1 cm. They were histologically ide,ntified as 19 adenomatous polyps, 3 hyperplastic polyps, 2 villous adenomas, 1 adenomatous polyp with carcinoma in situ, and 1 adenoacanthoma. Two invasive cancers were not TABLE 3. Anatomical location offlexible instrument (fluoroscopically proven) Location No. of patients % Sigmoid 3 16 Descending colon Splenic flexure Transverse colon Cecum 'n 84 seen with the rigid sigmoidoscope. One of these tumors was above 25 cm. The second was identified by rigid sigmoidoscopy at 15 cm, but was interpreted as localized inflammatory bowel disease. When seen with the flexible instrument it was clearly a 3-cm sessile carcinoma. Figure 4 graphically demonstrates the location and number of neoplastic lesions (benign polyps, malignant polyps, and invasive carcinomas) seen during the examination with each instrument. Of the 36 lesions, 16 (44%) were above the 20-cm level, beyond the reach of the average rigid sigmoidoscopic examination. Two patients had inflammatory bowel disease identified which was above the reach of the rigid sigmoidoscope. In 2 other patients with inflammatory bowel disease, the flexible instrument was advanced above the proximal extent of their disease and identified them as TABLE 4. Abnormalities discovered in 120 patients Abnormality No. of patients (%) Rigid Flexible Inflammatory bowel disease 7 (6) 9 (7.5) Polyps (benign) No. of patients with polyps 6 (5) 22 (18) Total polyps identified 6 30 Malignant polyp 1 (1) 3 (2.5) Carcinoma 1 (1) 3 (2.5) Stricture 0 2 (2) Diverticula 0 8 (7) Total 15 (13) 47 (39) FIG. 3. Comparative X-rays in the same patient showing anatomical location of rigid instrument in distal sigmoid (A), and flexible instrument in descending colon (B) when advanced to full length.

5 648 BOHLMAN ET AL. Vol. 72, No. 4, Part Average rig id exam 120 i, ml j 0IIIIIlI Rigid Sigmoidoscope ffilil Flexible Sigmoidoscope Average flexible exam I (55 em)! Distance from Anal Verge (em) FIG. 4. Bar graph demonstrating the location of the 36 polypoid lesions identified at sigmoidoscopy. All 36 lesions were seen with the flexible instrument, whereas only 8 were identified during the rigid examination. having localized distal ulcerative colitis. Flexible sigmoidoscopy revealed diverticula in 8 patients and benign stricture in 2. Six polyps were removed with the flexible instrument after both examinations had been completed. Discussion This report summarizes a preliminary experience with a new, flexible fiberoptic sigmoidoscope. This instrument was designed for the purpose of improving the diagnostic capabilities of the sigmoidoscopic exam and lessening the discomfort associated with rigid sigmoidoscopy. The results of this study demonstrate definite superiority of the flexible instrument. There are several features ofthe instrument which contribute to its value. The instrument's short length makes the distal tip responsive to small amounts of torque applied to the control head. This allows the operator to change the field of vision easily, expediting instrument insertion. The insertion tube of the instrument is constructed with more rigidity than previous model colonoscopes. The instrument thus acts as its own "stiffener," allowing for easier advancement through the tortuous loops. The wider turning radius of the bending section also facilitates insertion and advancement. The improved optics also provide excellent clarity of detail. An added feature of this instrument is the large diameter suction-biopsy channel. This enables one to utilize bigger forceps and thereby take larger biopsy samples. These forceps have potential value in increasing the diagnostic yield in sampling mass lesions. This channel also provides impressive suction capabilities (table O. Large amounts of retained stool, mucus, and blood can be aspirated without difficulty. The instrument also maintains this suction potential with the biopsy forceps in the channel, which lessens the need for a second suction channel. Patients in this study were examined in the conventional inverted (knee-chest) sigmoidoscopic position, rather than the left lateral approach. We chose this position because of the comparative nature of our study. This position, does, however, maintain the anatomical landmarks in their commonly recognized positions. This may make it easier for new operators to learn this procedure. The results of this study demonstrate that a safe, complete sigmoidoscopic examination can be performed quickly with a flexible sigmoidoscope, without extensive preparation and with no sedation. It is better tolerated than rigid sigmoidoscopy. Despite the fact that the fiberscope was inserted nearly 3 times farther than the rigid instrument, more patients preferred the flexible examination. The time required to complete the entire examination is also within reasonable limits, with an average time of just under 10 min. This instrument can inspect the proximal portion of the left colon, reaching the descending colon in 84% of patients studied. All of these factors contribute to the dramatic incfease in diagnostic yield demonstrated with this instrument (fig. 4 and table 4). The flexible instrument is of further value in the assessment of patients with inflammatory bowel disease. We discovered proximal Crohn's colitis in 2 patients who had a negative rigid sigmoidoscopic examination. We were able to evaluate adequately the extent and severity of inflammatory bowel disease in other patients. In 2 patients, benign sigmoid strictures were identified which were beyond the reach of the rigid instrument. In 8 other patients, diverticula were seen. The flexible instrument is clearly superior to the rigid instrument in the diagnosis of colonic neoplasms. Twenty-four benign polyps, two carcinomatous polyps, and two invasive sessile carcinomas were discovered at flexible sigmoidoscopy which were not seen during the rigid examination. Of these neoplasms, 56% were below the 20-cm level, within reach of but not seen with the rigid instrument. In no patient was an abnormality discovered by the rigid sigmoidoscope which was not seen during the flexible examination. Possible explanations for these observations are that there is a tendency, during the rigid examination, to stretch the bowel wall without actually traversing bowel lumen. False readings of distance of insertion are thus obtained. 2 Also, it is often difficult to distend the bowel lumen during the rigid examination, allowing smaller lesions to remain hidden behind prominent mucosal folds. These observations support our subjective impression that the flexible instrument allows for a more complete inspection of the rectosigmoid. The examiner can advance the instrument quickly to the distal descending colon, and can easily distend the bowel lumen and move the instrument tip to inspect each fold, thereby decreasing the possibility of missing a significant lesion. In addition, because multiple examiners with varying abilities took part in this study, observer variation may have played some role in the apparent superiority in the flexible instrument. Because colon cancer remains the most common form of internal cancer in America today with 100,000 new

6 April 1977 FlBEROPTIC PANSIGMOIDOSCOPY 649 cases diagnosed yearly3 and with 8 to 15% of the adult population harboring colonic polyps, 4 it is imperative that newer diagnostic tools be made available which will allow the physician to diagnose these problems at an earlier, curable stage. Because 70 to 80% of colonic neoplasms, polyps, and tumors are located below the mid-descending colon, it is apparent that flexible pansigmoidoscopy offers tremendous potential as a screening examination. Further large scale studies utilizing this instrument on asymptomatic patients are needed and planned. This study demonstrates that flexible pansigmoidoscopy is superior to the conventional rigid examination in the evaluation of patients with suspected colorectal disease. REFERENCES 1. Browne DC, McHardy G: An evaluation of routine proctosigmoidoscopy. South Med J 41: , Madigan MR, Halls JM: The extent of sigmoidoscopy shown on radiographs with reference to the rectosigmoid junction. Gut 9: , Bolt RJ: Sigmoidoscopy in detection and diagnosis in the asymptomatic individual. Cancer 28:121, McSwain B, Sadler RN, Main BF: Carcinoma of the colon, rectum and anus. Ann Surg 155:782, Axtell LM, Chiazze L Jr: Changing relative frequency of cancer of the colon and rectum in the United States. Cancer 19:750, Wolff WI, Shinya N: Earlier diagnosis of cancer of the colon through colonic endoscopy. Cancer 34:912, Salmon PR, Brasch RA, Ciccina C, et al: Clinical evaluation of fiberoptic sigmoidoscopy employing the Olympus CF -SB colo noscope. Gut 12: , Koyana Y: Fiberscopic examination of colo-rectal diseases. Am J Proctol 25(April):51-59, Bohlman TW, Smith FR: An evaluation offiberoptic sigmoidoscopy (abstr). Clin Res 23(Feb):103A, Berg, JW, Howell MA: The geographic pathology of bowel cancer. Cancer 34(suppl 807), 1974