What is Flexible Sigmoidoscopy?
Flexible sigmoidoscopy is a procedure that allows your doctor to examine the rectum and the lower bowel (sigmoid colon). This is performed using a narrow flexible tube called a colonoscope which has a camera in the tip that captures images of the inner lining of your bowel. These images are transmitted to a TV monitor which your specialist looks at during the examination. The colonoscope is inserted into your anus and slowly advanced into the rectum and the lower colon. It is an accurate and simple method of investigating the cause of rectal bleeding, change in bowel habits and rectal symptoms such as pain and diarrhoea.
What is the preparation for Flexible Sigmoidoscopy?
In order to obtain accurate results, the colon must be completely clean of stool. Instructions on how to cleanse your colon will be given to you by the MacMurray Centre. In general, this requires the use of one or two enemas prior to the procedure and may also call for a laxative and some dietary modifications. Under special circumstances, such as the presence of significant diarrhoea, the preparation may be waived.
The advantage over a full colonoscopy is that the bowel preparation is minimal; the disadvantage is that it will not be possible to view your entire bowel.
Inform your specialist of all prescription and non-prescription medication you are taking, as well as any allergies you may have. Unless otherwise instructed, continue taking any regularly prescribed medication. You may be told to stop taking blood-thinning medications for several days before the test. Stop taking iron supplements a week before the test, unless otherwise instructed by the health care provider, as iron residues produce a dark black stool which makes the view inside the bowel less clear.
How is a Flexible Sigmoidoscopy performed?
A Flexible Sigmoidoscopy is performed in a fully equipped examination room. In most instances you will be lying on your left side with your knees drawn up toward the chest. Your specialist will insert the colonoscope through the anus and gently advance through the rectum into the sigmoid colon. You may experience a sensation of fullness, bloating, pressure or cramping as the scope moves inside. You may also feel the urge to defecate but your bowel is empty and any residual liquid is removed with suction.
As the instrument is withdrawn, a careful examination is made of the lining of the colon. Tissue samples may be taken with tiny biopsy forceps inserted through the scope. Polyps may be removed with electrocautery snares, and photographs may be taken. Specialised procedures, such as argon plasma coagulation and endoscopic polyp and tumour resection, and dilatation of narrow areas may also be done.
Intravenous sedation can be used for the procedure but is not usually required. Most patients consider the test only slightly uncomfortable. The procedure generally takes about 5 to 15 minutes but could be longer particularly if you require any endoscopic treatment during the test.
What happens after a Flexible Sigmoidoscopy?
After your Flexible Sigmoidoscopy you will be wheeled into the recovery room where you will rest. You will be in the department for at least one hour after the procedure if you have received intravenous sedation.
When you wake up your specialist will discuss your examination results with you and a written summary will be given to you for your reference. A copy of your report will be sent to your GP.
A light snack will be served before you leave MacMurray. It is important to rehydrate (drink plenty of fluids) following your procedure. You are able to return to your normal diet following discharge.
If you have received sedation you must have someone to take you home after the test and stay with you, as you will be drowsy and unable to drive. The sedative may also affect your ability to recollect details about your procedure. Sedation should wear off in a few hours. You should stay off work the day of your procedure but can resume normal activities the following day.
If the doctor finds an area in the colon that needs further evaluation, a biopsy (small sample of tissue) can be obtained and sent to the pathology department for examination under a microscope. If a polyp is found, the specialist may remove the polyp at the same time. Polyps are small growths on the inner lining of the bowel. Most polyps are benign (not cancerous), but some polyps are precancerous. Patients with precancerous polyps are usually asked to return for a colonoscopy after a more vigorous colon cleansing.
Colonoscopy is a longer version of flexible sigmoidoscopy where the doctor examines the entire length of the colon. For more information, please read the Colonoscopy article. The advantage of colonoscopy over flexible sigmoidoscopy is the ability to find and remove polyps in the parts of colon that are beyond the reach of the flexible sigmoidoscope.
Removal of all of the precancerous polyps during colonoscopy has been shown to prevent colon cancer.
You may be asked to make a follow up appointment with your specialist to discuss biopsy results. Biopsy results will also be sent to your GP (may take up to five working days).
Sigmoidoscopy findings may include the following:
- Inflammatory bowel disease
- Lower gastrointestinal (GI) bleeding
- Polyps (which can be removed through the colonoscope during the exam)
Safety and Risks
A Flexible sigmoidoscopy is generally a very safe and simple test. Complications are rare but may include:
- Bowel perforation (a hole or tear in the wall of the colon), requiring a repair operation (fewer than 1 out of 1,000 tests).
- Heavy or persistent bleeding from biopsy or polyp-removal sites (1 out of 1,000 tests).
- Adverse reaction to sedative medication, causing breathing problems or low blood pressure (4 out of 10,000 tests).
- Infection requiring antibiotic therapy (very rare).
- Nausea, vomiting, bloating or rectal irritation.