A colonoscopy is a medical procedure designed to examine the entire length of the large intestine, also known as the colon. Many individuals have questions about the size of the instrument used, the colonoscope. This article addresses the instrument’s dimensions, design, and how it navigates the body.
Dimensions of the Colonoscope
The colonoscope is a long, flexible tube engineered to navigate the large intestine. Its length typically ranges from 130 to 170 centimeters (4.3 to 5.6 feet), which allows it to reach the far end of the colon.
The diameter of the colonoscope is often a primary concern for patients. Standard adult colonoscopes usually measure between 1.3 to 1.5 centimeters (0.5 to 0.6 inches) in outer diameter, roughly the thickness of an adult’s index finger or a garden hose. Specialized slim or pediatric colonoscopes are also available, with diameters as small as 0.7 to 1.2 centimeters for specific circumstances.
Design and Function of the Scope
The instrument is highly flexible, allowing it to conform to the colon’s natural shape. At its tip, it houses a tiny, high-definition camera and a powerful light source, which transmit real-time images of the colon’s interior to a monitor for the physician to view.
The colonoscope also contains multiple internal channels that serve various functions. One channel is dedicated to providing light, while another delivers water to clean the camera lens if it becomes obscured during the procedure. There is also a suction channel to remove any fluids or debris that might impede visibility. A working channel, typically 3.2 to 3.8 millimeters in diameter, allows the passage of miniature surgical instruments, such as biopsy forceps to collect tissue samples or snares to remove polyps.
Movement Inside the Colon
The colonoscope’s flexibility is important for its navigation through the large intestine. The physician carefully guides the scope by manipulating control knobs on the handle, which precisely angulate the tip of the instrument up, down, left, and right. This precise control allows the physician to steer the scope around the colon’s natural bends and loops.
To enhance visibility and facilitate movement, air or carbon dioxide (CO2) is gently insufflated into the colon through a channel in the scope. This process temporarily inflates the colon, gently opening its walls and providing a clearer view of the lining. Physicians also employ careful push, pull, and torque techniques, along with occasional patient position changes, to advance the scope smoothly and minimize discomfort while ensuring a thorough examination.