Colonoscopy: A journey through the colon and removal of polyps

Hi, I'm Dr. Darrell Gray. I'm a gastroenterologist and the Director of Community Engagement and

Equity in Digestive Health at The Ohio State Wexner Medical Center. I'm currently at the

University Hospital East Campus in the Endoscopy Suite and am about to perform a screening

colonoscopy. Colonoscopy is one of several measures or tests that can be used for screening

for colorectal cancer. It is the best test for examining the entire colon and both identifying

and removing precancerous lesions. Notably, for this exam, we use what's called a colonoscope.

A colonoscope is a flexible instrument in which we can use knobs to turn both left and

right, up and down in order to examine the entire colon. This device also has a camera

and a light on the tip of it that allows us to more thoroughly examine the colon and also

to take pictures. Now, albeit your colon is approximately 160 cm., or 60 in., or 5 ft.

depending on which measurement you use, we do not need to use 5 ft. of scope in order

to examine the colon because your colon is very compact inside of your abdomen. Now,

before we begin this procedure, we ensure that the patient is very comfortable. In this

case, our patient is under what we call conscious sedation. She's resting comfortably but able

to breathe on her own. And, we'll begin the exam. We're entering through the rectum, and

as we move beyond the rectum into the sigmoid colon, our goal is to gradually reach the

end of the colon, which is the ascending colon, and specifically the cecum. You'll notice

as we move along that the colon is characterized by nice, pink mucosa. And if you look very

closely, you can see veins along the mucosa. Now, the colon is not straight -- in fact,

there are a lot of twists and turns that you'll see as we move along this colon exam. Now,

this patient did a great job at preparing for this exam by taking a bowel prep. You'll

notice that there is very clear liquid inside the colon instead of brown and solid stool.

We are currently in the ascending colon and about to enter the cecum. And you'll notice

you've reached the cecum by looking at the landmarks. What we're look at there is called

the appendiceal orifice. On the other side of this orifice is your appendix. To the left,

you will notice the ileocecal valve. This is a valve that can be traversed to reach

the small intestine, called the terminal ileum that we are currently entering now. We are

now in the small intestine. You will notice a difference in the mucosa of the small intestine.

As you see there, its finger-like projections called villi that line the small intestine.

We can go further in the small intestine, but for the purpose of this exam our focus

is the colon. So we're now back into the cecum. And during this part of the examination, this

part is called the inspection. And so we slowly withdraw, being careful to exam the colonic

mucosa in a clockwise fashion. It doesn't necessarily have to be clockwise, but as long

as we are seeing a 360 degree view of the colonic wall. We use water to wash away any

stool or sediment, and we can use suctioning by which to withdraw that liquid. We inspect

carefully to look for polyps. Polyps are ingrowths of tissue that can occur within the colon,

and they can also be precancerous. If found, they would be removed at the time of the colonoscopy.

So we are moving from the ascending colon, now moving backward into the transverse colon,

again still using that same pattern of a clockwise movement to examine a 360 degree view

of the colon. We are now about to round another corner, moving, transitioning from the transverse

colon into the descending colon. Again, being very careful to remove any liquid and sediment

that we find along the way that could potentially hide any polyps. We've just transitioned from

the descending colon into the sigmoid colon. From the sigmoid colon, we move back to our

starting point, which is the rectum. At this point, the last part of the examination, we

do what's called a retroflexion, in which we turn the camera back on itself to look

at the anal verge and look for anything like polyps that could have been missed on the

way in, or hemorrhoids. In this case, our patient has some small hemorrhoids as you

can see there. But the good news for this patient today is that no polyps were found.

Now, let's look at a different patient. What you'll notice in this patient, as opposed

to the last patient we saw, is that on withdrawal we're encountering polyps. And so we're using

different techniques by which to remove polyps. What you're seeing here is we're using a snare.

A snare's a device that is like a wire or a lasso if you will, in which we can put a

loop around, wire this snare around a polyp and remove it. Either using it cold, or removing

the polyp cold, or using heat or cautery by which to remove the polyp. As a reminder,

polyps are ingrowths of tissue that potentially could lead to cancer. So, when we find them

in the colon, our goal is to remove them and remove them completely. Now you'll notice

two very large polyps here. One at 12 o'clock and the other at about six o'clock. Before

removing this large polyp, we chose to inject epinephrine to ensure that we minimize bleeding

from removal of this large polyp. Then, similar to the smaller polyps, we snared the polyp,

but in this case we chose to actually choke the polyp for awhile until we saw color change

and were confident that, indeed, we choked off the blood supply to this polyp before

removing it. Now, this polyp was too large to be suctioned into the suction portion of

the device. So, we actually had to remove that entire polyp from the colon; suctioning

it into the device and then removing the colonoscope. Here you'll notice a very large colonic mass.

And this is something that cannot be removed endoscopically and so we chose to use what's

called a forceps device by which we can take biopsies. Now we're slowly removing the colonoscope

until we reach again the starting point of the rectum, in which we'll do the retroflexion

and conclude our exam.