Water Immersion Colonoscopy Technique

Water Immersion Colonoscopy Technique

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Report on development of colonoscopist in short term


Colon endoscopes are painful for patients and are hard to master for practitioners. However, the "water immersion method" of placing a small amount of water without inserting any air at the time of insertion has a characteristic that there is little pain for the patient and it is easy for the surgeon to learn.

The less painful for the patient is that the slippage of the scope improves by putting in water, the scope is lighter due to the water in the intestinal tract, the scope gets lighter, the force to push the scope is as low as 500 gw or less, so the intestinal tract Do not stretch, because the intestinal tract does not stretch easily, that it can be shortened easily, because the amount of water to be added is as low as 200 ml so that there is no feeling of anger.

It is easier for operators to learn because in the water immersion method it is possible to insert in one pattern. Because it does not press with the water immersion method, because it does not make a loop, shortens the twist of the intestines and linearizes early, so the same insertion method as a relatively easy practice colon model can be used by humans. I have already taught more than 50 doctors, and the acquisition method of one pattern method has been established.


Purpose and method:

This time, a young doctor who has neither endoscopic experience nor upper and lower hands will report on the colonoscope with water immersion method and one-pattern method in a short time.

It was in the year of Heisei 28 that Dr. Tsutsumi Daimume wanted to learn the colonoscope of the water immersion method. Because there was no teaching environment at once, for the time being, I became self-study on the colon model. After three months of exercise practice with everyday colon model practice 100 times a day, the fastest 13 seconds to reach the insertion. This time is the fastest as I know, 7 seconds earlier than me. There is an empirical rule 1) that the average insertion time in humans is ten times as long as the colon model insertion time, according to which the average insertion time in his person was calculated as 2 minutes 10 seconds.

YouTube video, Dr. Tsutsumi colon model 13 seconds


In August 2017 we started training at a person at Shonan Atsugi Hospital. I have taught directly this one month only. From September I went to Osumi Kanaya Hospital and again I practiced endoscopy almost every day on weekdays. Table 1 shows changes in colonoscopic insertion time of Dr. Tsutsumi from September 2017 to April 2018, and Fig. 1 is a graph of this change.


Table 1. Changes of colonoscopic insertion time of Dr. Tsutsumi from September 2017 to April 2018 Table

Success / Total
Insertion rate%
Average time (min)
Standard dev (min)

















Figure 1. Changes in the colonoscope insertion time of Dr. Tsutsumi from September 2017 to April 2018
(Blue line: mean time (min), red line: standard deviation (min))


"In August, we received direct guidance from Mr. Gotou at Shonan Atsugi Hospital in Shonan Atsugi Hospital.At this time the colon received about 30 cases of radio training.As Mr. Goto guides me wirelessly, almost everyone can insert it In September, I transferred to Osumi Kanaya Hospital and started taking medical treatment carefully while interviewing veteran doctors on behalf of those who could not insert it.In October, there were few cases that exceeded 100 cases and can not be inserted, but it is still simple People will get in at once, but it takes time.In November, nearly 200 cases have been reached which are almost impossible to insert.It became possible to insert without pain than before, thanks to the patient. " (Tsutsumi) and improved monthly.

During the six months from September 2017 to April 2018, a total of 433 colonoscopy examinations were conducted. In September 2017, the average insertion time was 18 minutes and the standard deviation was 12 minutes, but in April 2018 the average insertion time was 8 minutes and the standard deviation was 5 minutes, more than twice as fast. "Now there are few people who have pain and I am confident about the insertion, I want to devise measures to reduce the number of cases that take more than 10 minutes in the future." (Tsutsumi) level. Since I have an average insertion time of 5 minutes and a standard deviation of 3 minutes, it seems that I will improve still more in the future, but it can be said that it is a very fast learning, considering that it usually takes several years for the master of colonoscopy.



In practicing the one-pattern method, first learn a unique scope handling technique that lets you know the position of the scope tip from the left hand position with scope 2). Next, learn the procedure of the one - pattern method by simulation method with right index finger as scope. 3)4) After that, practice until the insertion time of less than 1 minute with colon model 1-B of Kokusaiu and acquire a one-pattern method. This is the first month.

From the 2nd month I will be training with people. Since the colon model is a model of the air supply method, the intestinal tract collapses at the beginning with the water immersion method, and the direction of the lumen is difficult to grasp. For that reason, about a few dozen first cases, wireless teaching by a supervising doctor using a wireless microphone and wireless earphone is done. In the water immersion method, the lumen collapses because the amount of water to be added is small. If you do not get used to it, you can not find the direction of the lumen, so you may get a wrong recognition that the person is different from the colon model, to avoid it. When get used to finding the direction with reference to anonymous ditches etc., the insertion speed gets faster, and when I experienced about 100 people at the end of the 3 month training, I changed the impression that people are the same as the colon model. Ultimately, the human insertion time settles to about 10 times the colon model insertion time.

A one - pattern method has more than 50 experiences and teaching methods have been established and it seemed that everyone could learn in a short time. Although the water immersion method is less painful, it is easier to learn because it is inserted in one pattern. This time, it was confirmed by the guidance of Tsutsumi.



Finally, at Himeji Daiichi Hospital it is possible to visit the water immersion method and one-pattern method. Also please email any questions etc.



1) Goto Toshio: painless colon endoscope insertion manual by water immersion method, Chugai Medical College, Tokyo, Shinjuku-ku, Tokyo, 2016, p. 71 Colon model 10 times rule

2) Same as above, p.42 Law of double advancing angle

3) Same as above, p.65 Table 16-1 One-pattern method Description by part

4) Same as above, p.69 Table 17-2 Summary of one-pattern methods with finger endoscopy