The extent of sigmoidoscopy shown on radiographs with special reference to the rectosigmoid junction.

Abstract

The purpose of this investigation is to show what parts of the rectum and pelvic colon are seen on sigmoidoscopy, the reason for the occasional inability to pass the instrument to its full length, and the areas where special care is necessary in looking for lesions. METHODPatients referred for routine barium enema examination from St. Mark's Hospital Out-Patient Department were selected for this study. The very young, the aged and infirm, women of childbearing age, and those with painful local lesions were excluded. Sixty-two patients were examined.The double-constrast enema technique (Young, 1966), was used for the radiological investigation of the colon and at the end of this examination a 25 x 1-3 cm or 30 x 1-9 cm Lloyd-Davies type of sigmoidoscope was inserted. An occasional difficulty was due to pooling of residual liquid barium suspension in the rectum. Elaborate attempts were not made to clear the bowel of barium and if after several attempts the sigmoidoscope could not be passed to its full length it was strapped to the buttocks with adhesive tape. The length of tube inserted was carefully read at the anal margin. If fulllength insertion was achieved the sigmoidoscope was similarly taped to the buttocks. Two films were then made, one with the patient supine, and one with the patient in the left lateral position, using an overcouch tube with a focus-film distance of 48 in. The instrument was then removed.In some cases a Michel clip was attached to the mucosa using a long forceps, and the sigmoidoscope was then withdrawn before the films were taken. This allows for safer movement of the patient. Figure 1 is the double-contrast radiograph of the rectosigmoid region. Figure 2 shows the sigmoidoscope inserted to 25 cm. Figure 3 shows a Michel clip attached to the mucosa after withdrawal of the sigmoidoscope.A plaster of Paris cast of a fist was made, with extended index finger, which measured 8-5 cm from tip to web, with a partial lead covering to increase density. By means of a wooden rod fixed in the base a digital rectal 'Present address: St. Michael's Hospital, Toronto 2, Canada examination was simulated, while postero-anterior and left lateral exposures were made as before.Figures 4 and 5 show the limits of digital examination. The technique and dangers of sigmoidoscopy are covered adequately in most standard works on the rectum and colon. A reminder of the anatomy of the rectum will assist in interpretating the radiographs. ANATOMY RECTUM The rectum ends distally by becoming continuous with the anal canal, which site is readily recognized by palpation of the ano-rectal ring, the ridge of pubo-rectalis muscle felt where the anorectal junction is angulated forward as it passes through the levator diaphragm. This point is about 3 cm from the anal margin. The rectum is about 12 cm long, following the curve of the sacrum. From above downward it also has three lateral bends, to the right, left, and right again, recognizable from the lumen as folds of the rectal wall, the valves of Houston. These are more con...

Sigmoidoscopy/proctoscopy service with open access to general practitioners.

“…In patients with symptoms a yield for carcinoma of 4-6% has been reported.6 Unfortunately, that approach still resulted in detection of only 11% of malignant tumours in Dukes's stage A and a false negative rate for rectal carcinoma of 45 4%.6 Screening for presymptomatic disease by occult blood testing has been shown to increase the proportion of stage A tumours diagnosed to 75%.7 Hence possibly a combination of sigmoidoscopy and occult blood testing will produce the best early detection rate for colorectal carcinoma. The frequency with which the rigid sigmoidoscope could be used to examine beyond the rectosigmoid junction in this series (33%; 478 cases) was similar to that reported by others.8 9 Probably this could be increased to about 70% with the use of a routine enema before examination, but this would place extra demands on the nursing staff and cause needless discomfort to some patients. In view of the limitations of rigid sigmoidoscopy, however, it is not surprising that fibreoptic sigmoidoscopy is becoming increasingly popular.…”

Rigid or Flexible Sigmoidoscopy in Colorectal Clinics? Appraisal Through a Systematic Review and Meta-analysis

“…Because of the limited examination achieved by rigid sigmoidoscopy relative to the distribution of colorectal lesions, this technique only allows for exclusion of more distally located pathologies and does not necessarily give a clue about the proximal lesions. 4,5 Although flexible sigmoidoscopy is expected to overcome the limitations of rigid examination, its role in colorectal clinics has not been acknowledged to date. 6 The flexible technology in gastrointestinal endoscopy has failed to eliminate the use of rigid sigmoidoscopy in colorectal clinics.…”