2023-11-28 14:00:19
The secrets of the digestive endoscope
“We have different devices with their relevant tools depending on the area to be studied and treated: nasograstroscope, esophagoscope, gastroscope, enteroscope, colonoscope, sigmoidoscope or proctoscope,” relates Dr. José Carlos Marín Gabriel, digestive system specialist at Hospital 12. October of Madrid.
“Our objective is to detect any hidden pathology in the different tissues of the digestive tract, whether or not it has previously offered external symptoms, and to proceed with on-site treatment if necessary,” says the also scientific director of the Clinical Institute of the Digestive System (ICAdig).
He Dr. José Carlos Marín Gabriel He is also an associate professor at the Faculty of Medicine of the Complutense University of Madrid (UCM), an expert in advanced digestive endoscopy and high-risk consultation for digestive tumors, and is part of the Endoscopy Committee of the World Gastroenterology Organization.
Doctor Marín Gabriel, what is the digestive endoscope and what is it for?
A digestive endoscope is a minimally invasive diagnostic and treatment technological instrument that is introduced into the human body to visually examine the interior of the digestive tract through what doctors call the natural orifices: mouth, anus and nose.
The endoscopic technique allows us to detect hidden ailments and diseases (ulcers, polyps or cancers in different stages) in the digestive system (esophagus, stomach, small intestines -duodenum, jejunum and ileum- and large intestines -cecum, colon and rectum-).
What is a standard endoscope physically like?
The endoscopic device actually consists of two complementary systems: the head or operating control knob, which is extended by the flexible insertion tube, at the distal end of which the mini-chamber, the illuminator and the working channels are located; as well as the external image processor, with its lighting source and monitor.
And where are the images from the endoscopic microcamera seen?
The high-definition mini camera is connected by a cable to the image processor. This processor converts the video signal from the tip of the insertion tube or shaft into an image that is then clearly displayed on the external display monitor in real time.
With the processor, parameters such as brightness, contrast or color are adjusted to optimize the image seen by the endoscopist.
Some endoscopes even have diagnostic improvement systems that allow the lesions of the digestive tract to be visualized with greater clarity and definition, such as digital chromoendoscopy (highlighting the characteristics of the internal tissues), which is often activated with a simple button from the operating control. .
As in so many things in our daily lives, technology has greatly helped digestive system specialists: different studies have shown that by moving from standard definition images to high resolution images our ability to detect polyps in the colon, for example , improved exponentially.
Returning to the endoscope, what function does the operating handle serve?
He operational mango in endoscopy it is the part of the device that the digestive system specialist holds, handles and controls: it directs the movement of the distal tip of the insertion tuben.
Basically, it consists of two wheelsa large wheel, which allows us to make movements from top to bottom, and another smaller one, located next to the previous one, to make movements from right to left.
The wheels are accompanied by tensioners that run internally along the shaft to the tip of the endoscope, like a bicycle chain; gear that allows the smooth execution of the movement ordered by the wheels operated by the endoscopist.
Furthermore, each of these wheels has a small lever that acts as a brake; It is used when the insertion tube demonstrates some instability in the area of visual field in which you are working.
Dr. Marín Gabriel, it looks like a video game controller… What else can they do?
The walls of the digestive tube are folded, logically. For example, the stomach and colon do not have air inside that could allow the walls to be separated for observation and analysis.
For this purpose, the endoscope has two valves in the operating head at the disposal of the specialist doctor:
The insufflation valve It allows air or CO2 gas to be introduced into the digestive tract in order to separate the functionally joined walls and properly see the lining of this tissue, the mucosal layer, which is what endoscopists are interested in.
Air insufflation is more common due, in many cases, to the sanitary deficiencies of a special system to insufflate CO2, a gas that is less bothersome for patients, since abdominal swelling is less after the intervention.
When we activate this valve, it also allows us to clean with a little water the tip of the endoscope (mini camera and luminaires), which may be fogged or with adhered elements that make it dirty.
The suction valve It allows just the opposite, since it serves to remove the air or gas that we have introduced, achieving the well-being of the patient.
Furthermore, by renewing the indoor air, some flat lesions can be better seen, such as serrated polyps in the colon, which are more difficult to capture with the naked eye of a monitor.
At the same time, aspiration removes the contents of the digestive tract that prevent detailed observation, such as remains of saliva from the stomach or feces in the colon.
It is also possible to introduce operational tools through what we call the endoscope working channel. At the same time, this channel facilitates the aspiration of unnecessary contents of the digestive tract.
Doctor, we see two buttons (1 and 2) in the detailed photograph of the endoscopic handle. What are they used for?
We have buttons assignable that allow us to take photographs and videos to include in the reports resulting from the endoscopic test.
Including images is essential both to ensure the quality of the diagnosis and treatment put into practice, and to contrast our medical opinions among the different related specialists.
Some advanced endoscope models incorporate a button to modify the coloration of the images that the endoscopist is seeing on the monitor, which is called cromoendoscopia.
Some more advanced endoscopes even have buttons that allow you to magnify the scan image much more; By pressing the button you get a kind of zoom or magnifying glass effect which helps to observe and analyze the details of the injuries.
Also, there are endoscopes that have a type of wheel on their handle that provides greater rigidity to the endoscope shaft or insertion tube.
This system of variable stiffness It allows us to progress more easily through the different sections of the digestive tube, helping the endoscope advance to the end point desired by the endoscopist.
And the endoscopic tube that is inserted into the body reaches every corner?
Yes, and its length depends on the organs we intend to visualize. The shaft of the insertion tube is longer for a colonoscope and shorter for a gastroscopy.
In any case, the tubes are marked on the outside with white stripes that allow us to know which area of the digestive system we are working on: these marks are displayed every five centimeters from the distal tip in a gastroscope and every ten centimeters in the case of a colonoscope.
The tip of the insertion tube uses light guides that allow us to visualize inside the wall of the organ to be studied. It is essential to provide light because inside the human body, as happens in the digestive system, there is no natural or other type of lighting.
Doctor Marín, And how is the endoscope controlled during the examination?
The endoscopist usually holds the control handle with the left hand and handles the flexible insertion tube with the right; She gently directs it towards the interior of the organ to be examined.
By pure logic, handling the endoscope requires some manual dexterity, as with any other technique in medicine. It takes practice and experience to control the movements and not hurt the patient.
At the beginning, when you are learning, it has always been a complicated technique for all of us; But over time, the brain, hands and eyes come together so that exploration, diagnosis and treatment are perfectly combined with all parts of the endoscope.
Doctor, we already know that technology adapts to patients, but are all endoscopes the same?
There are small variations, such as nasogastroscopio, which has a very thin diameter (5.9 or 6 mm) to pass through the nose; or the enteroscope You should be able to use one or two balloons in the small intestine.
Another example would be the colangioscopio, perhaps the thinnest endoscope we have, and which allows us to see inside the bile duct. That was unfeasible until a few years ago.
But there are undoubtedly two endoscopes that are clearly special, used for a long time.
He duodenoscopio It is used to perform the ERCP test (endoscopic retrograde cholangiopancreatography). With this test, what we can do is diagnose and, above all, treat diseases of the bile duct and pancreas.
The most peculiar thing about this endoscope is that the mini-camera is arranged on one side of the tip of the insertion tube. The rest of the endoscopes have frontal vision.
And this is because it allows us to better see the area where the bile duct empties into the digestive tube (duodenum), in the area we call the Vater papilla.
With the duodenoscope, a stinterotomy can be performed to improve the opening of the bile outflow channel; remove stones from the bile duct (fluid crystallizations) or dilate its stricture (narrowing); even place prostheses when this canal is obstructed.
The other peculiarity that this type of endoscope has is that it has an elevator claw that is located at the end where the working channel ends. It allows you to better direct certain specific instruments for this ERCP test.
Radial endoscopy of pancreatic cancer, with visualization of blood vessels linked to the tumor. The puncture of the pancreatic tumor, using a fine needle that is introduced through the working channel, aims to obtain cells for the most accurate diagnosis possible. Great care will have to be taken not to puncture the blood vessels affected by the neoplasia. All images are provided to EFEsalud by Dr. Marín Gabriel.
We are talking about another special device with the ecoendoscopiotube that has an ultrasound probe at its distal tip.
The echoendoscope allows us to analyze, using ultrasound techniques, the different layers of the digestive tract itself and, in addition, what happens in the lymph nodes and in the walls of other adjacent organs, such as the pancreas.
There are two basic configurations of the echoendoscope depending on the ultrasound probe.
Radial or probe perpendicular to the axis of the endoscope, which allows obtaining 360º images.
Lineal or longitudinal probe to the axis of the endoscope, which allows observing only the area where the endoscopic tip will rest.
Linear probes incorporate a channel that allows the introduction of a needle for taking samples, as well as other materials to place prostheses or drain cavities.
In the next Digestive System videoblog We will conduct an interview about the most common tools used in digestive endoscopy.
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