This ASG video tip is sponsored by Braintree, maker of the newly approved Souflave and Soutab. The aim of good colonoscopic insertion is getting to the C-cum efficiently using good technique with the least amount of scope insertion, which is basically having the straightest possible scope, least amount of colonic distension with gas, which is CO2 nowadays that we use routinely, and also avoiding complications, which is basically by not pushing against fixed resistance and also avoiding loops and reducing loops when they form. And one of the most important things as we do more and more difficult colonoscopies is the willingness to quit. I mean, there is no harm in quitting when in spite of your best efforts, you are unable to reach the C-cum. So let's review some of the anatomical considerations for the colon. The colon has a couple of mobile areas, which is the sigmoid and the transverse colon. Certain areas of the colon can be stretched and elongated, which is the sigmoid, the transverse, and the flexures. You can encounter sharp turns and twists in the colon, which is mainly in the rectosigmoid region, the sigmoid, as well as the flexures. And how the colon behaves during colonoscopy is also impacted by a lot of other factors, like the body habitus, the intra-abdominal fat, scarring from prior surgeries, history of diabeticculosis and diabetic litis, presence of ventral or inguinal hernias, presence of history of radiation therapy, and presence of ascites. So if you look at the difficult or the defined colon, there are basically two main problems that we encounter. One is sharp fixed turn or a sharp angulation, or a redundant colon, which results in a lot of looping. So there are certain things that we should always consider and do during colonoscopy, which is to take a good history, which would include history of previous abdominal surgeries, history of radiation therapy, history of previous episodes of diabetic litis, what has been the previous experience of the patient with colonoscopy. We should also examine the abdomen, at least put your hand on the abdomen when you do the consent to examine for laxity of the abdominal wall musculature, look for any evidence of ventral hernia, surgical scars, or inguinal hernia. If available, always try to review the previous colonoscopy report, because that might give you some information as to what is to be expected. And one of the most important things which I always emphasize to our fellows is describe the difficulty you encounter in your report, as well as the measures you took to successfully reach the CEQA, whether it was pressure, turning the patient over, using a different score, what have you. And this is very important for future reference, because if you have difficulty negotiating the colon, the same difficulty will probably happen in a future colonoscopy. So let's talk about both these issues separately. So what about the sharp fixed angulation? This is more commonly seen in women with history of low abdominal or pelvic surgery, elderly patients with stenosing diverticular disease. As I said, always try to review the previous colonoscopy report if it is available to see if the endoscopist had any difficulty or mentioned that there was a sharp turn or not. If you know based on previous information that there is a sharp or fixed angulation in the sigmoid, then you may start the procedure from the get-go with a pediatric colonoscope. And if that is not successful, then even move on to a gastroscope. I usually start with an adult colonoscope because the adult colonoscope is more stiff and loops less. But the only situation where I go with a PCF from the get-go would be prior knowledge of a fixed sharp angulation in the sigmoid. You should always hold, and this is for any procedure, you should always hold the scope with your fingers rather than with your hand. And this is because the fingers are more sensitive and they appreciate the tactile perception against the resistance much better than when you're holding it with the fist or clenching on the shaft of the scope. One of the most important things that you can do for sharp fixed angulation is not to insufflate gas, but on the contrary insufflate fluid. And this is just a schematic showing that when you insufflate gas, it distends the sigmoid colon, lengthens it, makes the angle here more acute compared to when you fill the sigmoid with water, which makes it heavy, makes it straighter, makes this turn less acute. And the other, and all these will help you to negotiate to the turn. And the other important thing which we sometimes forget is continuous gas insufflation with a sharp turn or a sharp fixed angulation will result or can result in barotrauma because you're filling the colon with gas, you're struggling, it's a long procedure, all the CO2 travels upstream to the cecum. And if you have a competent IC valve, it gets, it comes to a dead end. And this is the area where you can see barotrauma, which will be in the form of linear mucosal tears and lacerations. So that is something to keep in mind. I always teach the fellows when they're doing procedures with me that torquing the scope at angulation is more important, turning the dials and torquing is more important than just pushing because as you can see in this diagram, when you push at an angle, you basically make the angle more acute and more difficult to negotiate. So torque the scope rather than pushing, turn the dial up down dial with your left thumb, keep the scope short and straight. And if after your maximum torque and moving up down dial, you're unable to negotiate the turn, then it's the time to use the left hand grip so that you can feed the right hand and and use the right hand to move the dials, the short dial or the small dial for right left deviation. So you take your right hand off the scope, you hold the scope shaft with your little finger of the left hand, and then you use your right hand to move the small dial to get further turn to negotiate a sharp angulation. Now, if all that is not making you negotiate the turn is not successful, then you can apply pressure and the direction of the position of the pressure should be in the right lower quadrant directed middly and downwards. And if that is also not helping, then it's about it's time to change the scope, either go to a PCF first or pediatric colonoscope. And if that does not help, then you can even go in with an upper endoscope. And here you can see that the bending section of the PCF and the gastroscope compared to the colonoscope is much shorter, and the entire curve or this area that you have of the bending section is much smaller for the pediatric colonoscope and the gastroscope compared to the adult colonoscope. If that is also not helping, then it's time to change the position of the patient to supine and apply right low quadrant pressure. And if that also does not help, then change the position to right lateral position. I usually do the change of the scope or I change the scope before I change the position of the patient just because with more and more procedures being done under a MAC or under propofol is just cumbersome to change the position of the patients. You need a lot of help. But if it comes to that point, then you will have to do that. I just wanted to show you that never underestimate the value of changing the scope to a smaller diameter scope, because this is what happens if you have the adult scope as the reference, the diameter of the pediatric colonoscope is about 10% less. But if you look at the circumference, the reduction in the circumference is 20% because the circumference is 2 pi r. So if you and similarly for the gastroscope, the gastroscope diameter is 25% less than the colonoscope diameter, and the surface area is almost close to 45% lower than the colonoscope diameter. And the other thing to remember is that when you have a sharp fixed angulation in the sigmoid and you negotiate it with a gastroscope, usually after that, it's a straight shot to the cecum. So even with the limited length of the gastroscope, majority of the times you'll read the cecum because that fixed angulation is tethering and fixing the colon and avoiding any loops. And that will be enough for you to get to the cecum even with the limited length of the gastroscope. These are just the degrees of deflection of these scopes. And this is important to remember also, because sometimes we have older scopes, the cables are loose, and the deflection of the scope is not what it should be. And that can be a limitation or a limiting factor when you are trying to negotiate a sharp fixed turn. So something to keep in mind is to pull the scope out and check the deflection. And for that, you should know the ballpark degrees of deflection up, down, right, left of different kinds of scopes. So another thing that has been shown to be beneficial is starting the procedure in the right lateral position instead of the left lateral position. One study showed that in women and in patients with history of abdominal surgery, you've got to the cecum faster when the starting position was right lateral. But overall, meta-analysis have not shown a significant difference in the cecal intubation rates and time between these two positions. But something to keep in mind in difficult cases where you have been unsuccessful in reaching the cecum or negotiating the sharp turn in the left lateral position after using all the other remedial methods that we discussed before.

colonoscopic insertion

CO2 gas

complications

anatomical factors

scope deflection