What Is Sigmoidoscopy and How Does It Differ from Colonoscopy?
When it comes to diagnosing colon-related issues, sigmoidoscopy and colonoscopy are two common procedures that may be recommended by your doctor. Although both are used to examine parts of the colon, they serve different purposes and examine different areas. Here, we’ll break down each procedure and discuss their differences to help you better understand which may be right for you.
What Is Sigmoidoscopy?
A sigmoidoscopy is a medical procedure that focuses on examining the lower part of the colon, known as the sigmoid colon. It’s performed using a flexible tube called a sigmoidoscope, which has a camera and light at the end. This allows the doctor to visualize the lining of the rectum and sigmoid colon.
Common Uses for Sigmoidoscopy:
- Screening for colorectal cancer in the lower colon.
- Diagnosing conditions like diverticulitis or ulcerative colitis.
- Investigating symptoms such as rectal bleeding or chronic diarrhea.
What Is Colonoscopy?
A colonoscopy is a more comprehensive procedure that allows doctors to examine the entire length of the colon. It’s done using a colonoscope, which is similar to the sigmoidoscope but longer, enabling a full examination of the colon, from the rectum all the way to the cecum.
Common Uses for Colonoscopy:
- Routine cancer screening: Recommended for adults aged 45+ for comprehensive cancer screening.
- Diagnosing issues like inflammatory bowel disease (IBD), polyps, or tumors throughout the entire colon.
- Following up after abnormal findings during a sigmoidoscopy.
Key Differences Between Sigmoidoscopy and Colonoscopy
Here’s a quick breakdown of the major differences between the two procedures:
| Feature | Sigmoidoscopy | Colonoscopy |
| Area Examined | Lower third of the colon (sigmoid colon and rectum) | Entire colon (from rectum to cecum) |
| Procedure Duration | 10 to 20 minutes | 30 to 60 minutes |
| Purpose | Screening and diagnosing issues in the lower colon | Comprehensive screening for the entire colon |
| Preparation | Typically requires an enema or mild bowel prep | Full bowel preparation (cleansing the entire colon) |
| Sedation | Usually no sedation required | Sedation is commonly used |
| Cancer Detection | Limited to the lower part of the colon | Full colon cancer screening |
| Polyp Removal | Can remove polyps, but only in the lower colon | Can remove polyps from the entire colon |
| Follow-up Needed | Further tests may be required if issues are found | No additional tests usually required after procedure |
Which Procedure Is Right for You?
The decision between sigmoidoscopy and colonoscopy depends on your symptoms, risk factors, and what your doctor is trying to examine. Sigmoidoscopies are less invasive and can be quicker for those who only need to examine the lower part of the colon. However, if there are concerns about the entire colon, or if you’re at higher risk for colorectal cancer, a colonoscopy is likely the best option.
Conclusion
Both sigmoidoscopies and colonoscopies play a critical role in diagnosing and treating colon-related issues. Whether you're due for a routine screening or experiencing symptoms like unexplained abdominal pain or changes in bowel habits, it’s important to consult with a gastroenterologist to determine the best course of action.
If you’re experiencing any digestive issues or need a routine screening, Digestive & Liver Disease Consultants (DLDC) can help. Contact our expert gastroenterologists today to schedule an appointment and ensure your digestive health is in good hands.
