What is a Sigmoidoscopy vs. a Colonoscopy?
What Is a Sigmoidoscopy?
A sigmoidoscopy is a medical procedure in which a physician uses a short, flexible tube with a camera (called a sigmoidoscope) to examine the lower portion of the large intestine — specifically the sigmoid colon and rectum. Unlike a colonoscopy, which examines the entire colon, a sigmoidoscopy only evaluates the last two to three feet of the large intestine.
Sigmoidoscopy vs. Colonoscopy: Key Differences
The two procedures are related but serve different purposes and have important differences:
- Scope of examination: A colonoscopy examines the entire colon (approximately five to six feet). A sigmoidoscopy examines only the lower colon and rectum — roughly the last two to three feet. This means a sigmoidoscopy cannot detect cancer or polyps in the right or transverse colon.
- Preparation: A colonoscopy requires a full bowel prep (liquid diet and laxatives the day before). A sigmoidoscopy typically requires only an enema or limited bowel prep.
- Sedation: Colonoscopies are usually performed with sedation. Flexible sigmoidoscopies often are not, making them more uncomfortable but simpler to perform.
- Screening recommendations: The U.S. Preventive Services Task Force previously recommended flexible sigmoidoscopy every five years (sometimes combined with annual FOBT) as an alternative colorectal cancer screening method. However, colonoscopy has largely become the preferred screening tool in the United States due to its completeness.
Limitations of Sigmoidoscopy
Because sigmoidoscopy examines only the lower portion of the colon, it cannot detect abnormalities in the upper colon. Studies have shown that a significant percentage of colorectal cancers and advanced polyps occur in areas of the colon that are not visualized during sigmoidoscopy. For this reason, if a sigmoidoscopy detects polyps or other abnormalities, a follow-up colonoscopy is typically recommended to examine the rest of the colon.
Sigmoidoscopy and Medical Malpractice
Medical malpractice issues related to sigmoidoscopy most often arise when:
- A provider performs only a sigmoidoscopy when a full colonoscopy was clinically indicated, resulting in a missed diagnosis of cancer in the upper colon
- Polyps or lesions found during a sigmoidoscopy are not properly followed up with a complete colonoscopy
- The procedure is performed negligently, resulting in perforation or other complications
- Findings are not properly documented or communicated to the patient
If you or a family member has been diagnosed with colorectal cancer following a prior sigmoidoscopy that reportedly showed no problems, an experienced Pennsylvania medical malpractice attorney can evaluate whether the prior screening was performed to the appropriate standard of care and whether a delayed diagnosis claim may be available.
