This chapter is focused on the key aspects of ileocolonoscopy to enable the reader to achieve a high level of skill with the goal of 100% ileocecal intubation and a proper recognition of common and rare pathology of the terminal ileum and the colon.

Bowel preparation for colonoscopy

Poor bowel preparation is a major factor that may prevent or complicate successful ileocolonoscopy. Emphasizing the importance of bowel preparation, in 2006 the American Society for Gastrointestinal Endoscopy and American College of Gastroenterology Taskforce on Quality in Endoscopy suggested that every colonoscopy report should include an assessment of the quality of bowel preparation. Preparing infants and small children for colonoscopy can be challenging. The major obstacles are the volume and distasteful nature of laxatives and a restrictive diet.

The impact of inadequate or poor preparation for ileocolonoscopy in children is magnified by the necessity for deep sedation or general anesthesia and specifics of bowel preparation, especially in small children. Furthermore, multiple attempts to aspirate large amounts of semisolid stool often lead to clogging of the instrumental channel. Repeat efforts to restore adequate suction precipitate excessive insufflation and stretching of the large intestine and adjacent mesentery and, in conjunction with poor visibility, contribute to a big loop formation, making the procedure more challenging. Therefore, despite a “natural” temptation to complete ileocolonoscopy, it is wise to terminate the procedure if the colon is not adequately prepped. This is especially relevant for patients with suspected or diagnosed chronic inflammatory bowel disease and children with anemia and/or rectal bleeding.

An adequate bowel preparation targets two important goals: maximum visibility and thorough examination of the entire colon and the terminal ileum, and prevention of complications.

Although administration of cleansing regimens is not always easy, modern protocols can be remarkably effective in cleaning the colon and ileum. Currently, three types of products are commonly used: polyethylene glycol (PEG) with electrolytes, PEG 3350 and sodium picosulfate/magnesium citrate (PICO). Large‐volume PEG with electrolytes is generally less tolerable, especially in younger children. A combination of propulsion agents such as Senokot® and PICO (Pico‐Salax® or Prepopik®, Ferring Pharmaceutical) has found favour because of increased tolerance and compliance. More recent low‐volume PEG without electrolytes regimens are becoming increasingly popular in pediatric units and are well tolerated, with no observable electrolytic disturbance.

In general, large‐volume PEG with electrolytes is less tolerable. especially for younger children as well as placement of a nasogastric (NG) tube which should be avoided if possible.

The key to successful bowel preparation for ileocolonoscopy is patient/parental compliance/cooperation and adherence to the chosen regimen tailored to the child’s age. Several studies including prospective data collection from 14 pediatric US centers (almost 22 000 colonoscopies) published in 2016 reinforced the importance of differential approaches to bowel preparation based on the child’s age. According to the Practice Committee of the American Society for Gastrointestinal Endoscopy (ASGE) and Israel Society for Paediatric Gastroenterology and Nutrition, a clear liquid diet for 24 hours and a normal saline solution enema (5 mL/kg) may suffice for infants younger than 2 years of age.

Our approach to bowel preparation for infants below 2 years of age is slightly different. Although it is debatable, we do not prep the colon in infants less than 4 months old. It is quite easy to irrigate and aspirate the small amount of liquid and semiliquid stool during the procedure.

In infants between 4 and 12 months of age, we achieve satisfactory results of colonic cleansing by using a liquid diet and milk of magnesia (1 mL/kg per dose twice a day) for two consecutive days prior to the procedure. For children 1–2 years of age, we recommend a combination of Senokot 0.5–1 mg/kg and sodium picosulfate ¼ sachet on two occasions the day before colonoscopy.

Based on the published data and our extensive personal experience, preferred methods of bowel preparation for children 2 years and older are PEG 3350 or PICO with Senokot in combination with a clear liquid diet (CLD) the day before colonoscopy. Liberal drinking is essential for successful cleansing and prevention of dehydration.

PEG 3350 solution is prepared as a mixture of 238 g of polyethylene glycol if purchased over the counter or 255 g if obtained by prescription. For older children, the suggested volume of PEG 3350 solution is 1.9 L. For younger children, it is recommended to take the PEG 3350 mixture until two consecutive clear stools are passed.

A recommended dose of PEG 3350 for one‐ and two‐day regimens is 4 g/kg and 2 g/kg respectively for children with bodyweight below 50 kg or 238 g for patients whose weight is above 50 kg. The solution is prepared as a mixture of PEG 3350 with flavored sport drinks.

The quality of bowel preparation with PICO with Senokot is equal to PEG regimens but it is more tolerable for children. The age‐specific doses are ¼ sachet (2.5 g) for children 1–6 years of age, ½ sachet for children 6–12 years of age, and one sachet for older children from 12 to 18 years of age, given twice with a 6–12 hour interval the day before colonoscopy. Each dose is diluted in 150 mL of cold water and taken twice at 4 pm and 6 hours later the day before colonoscopy. Intake of additional clear fluid after each dose (up to 1 L) should be encouraged.

If a large‐volume lavage method (PEG with electrolytes) is chosen, the patient can eat and drink up until the afternoon of the day before the procedure. The patient is then asked to fast overnight. Flavored solutions are available. The cleansing agent (5–10 mL/kg up to 250 mL per dose) is given by mouth every 10 minutes until the rectal effluent is clear. There are some adolescents and teenagers who will accomplish this preparation readily but hospitalization for 24–48 hours. A nasogastric tube placement may be necessary for uncooperative patients. This is one reason why low‐volume protocols are the preferred method in children and adolescents.

In recent years, serious side effects of oral sodium phosphate colonic lavage in adults have been reported. Among these were cases of fatal hyperphosphatemia with hypocalcemia, hypokalemia, dehydration and acute nephrocalcinosis with renal failure. Currently, we would not recommend sodium phosphate for colonic cleansing in children and teenagers.

Enemas are not routinely used for children, especially those with suspected inflammatory bowel disease, as they cause erythema, edema and petechiae of rectal and distal sigmoid mucosa, complicating the interpretation of endoscopic findings, but in certain circumstances they can help if the effluent is not clear two hours before the procedure.

The benefit of intravenous antispasmodic agents administered directly before the ileocolonoscopy has been demonstrated, for example hyoscine 20 mg administered intravenously. The use of such an agent given just prior to colonoscopy is determined by personal preference. Their use may facilitate luminal visualization but it may also increase the compliance of the colon, theoretically allowing a greater chance of loop formation. They are certainly of benefit in spastic colonic situations. It should be remembered that they work only for a short period of time, 5–10 minutes, and they may be readministered in certain situations, such as when one needs to relax a haustral fold if a polyp is just beyond and obscured by it, or to relax a spastic ileocecal valve. Glucagon is a longer‐acting intestinal paralytic which can last for an hour or more; approximate dosing regimens are IV 0.5 mg under 20 kg body weight, IV 1 mg over 20 kg body weight. This is particularly useful in longer procedures such as enteroscopy (see Chapter 14). Clinically significant hyperglycemia is not seen.

Indications for ileocolonoscopy

Indications are covered in Chapter 10.

Contraindications for ileocolonoscopy

There are few absolute contraindications to attempting ileocolonoscopy in children (Table 12.1). In cases of fulminant colitis, careful examination of the rectum and distal sigmoid colon may be attempted by experts. Generally, ileocolonoscopy is delayed for at least 8 weeks following ileal pouch or other surgeries associated with colon exploration. Connective tissue disorders such as Ehlers–Danlos should be approached with care and understanding of the increased risk of perforation. Clearly, known intestinal perforation or peritonitis are absolute contraindications as well as absolute neutrophil count below 500.

Equipment

Three types of colonoscopies are available for routine diagnostic investigation in children: standard “adult” instruments with outer diameters 12.8–13.2 mm (Table 12.2), slim “pediatric” scopes with outer diameter 11.5–11.6 mm (Table 12.3), and ultra‐slim scopes with outer diameter of 9.5–9.8 mm (Table 12.4). We would refer the reader to the manufacturers, however, as these specifications change and advance regularly.

The extra stiffness of the adult version diminishes the likelihood of forming sigmoid loops, but extra care must then be taken, especially in younger children under general anesthesia, not to advance against undue resistance, to avoid the unlikely complication of colonic perforation. The large diameter of the adult colonoscope can also limit maneuverability within the smaller colonic lumen of a young child.

Slim pediatric and ultra‐slim colonoscopes are more flexible and have a higher propensity to form loops. However, these instruments have an adjustable stiffness mechanism operated by a dial on the control section right below the biopsy channel, which allows the insertion tube to be made stiffer when passing through the sigmoid and transverse colon, decreasing the chance of sigmoid loops. Colonoscopes with adjustable stiffness should be standard in all pediatric centers conducting colonoscopy. In respect of training, the new generation of adult colonoscopes are equipped with electromagnetic coils incorporated within the shaft, which give the endoscopist a 3D view of the shape and position of the colonoscope within the patient’s colon. This technology is now integrated into the standard hands‐on colonoscopy courses offered in training centers and accelerates the learning curve especially in comprehension of loop formation and resolution (Scope Guide®, Olympus). A “through‐the‐scope” (via biopsy channel) version that is removable and reusable is also available.

There is a limited amount of published data to support the choice of colonoscope use in children. Recently, data from Japan suggest the use of a standard or pediatric colonoscope in patients weighing 12–15 kg or above, infant or standard adult gastroscopes in patients weighing 5–12 kg, and ultra‐thin gastroscopes in patients weighing <5 kg.

Based on our large personal experience, the lower limit for the standard adult colonoscope is 3–4 years of age and/or 12–15 kg. A slim colonoscope can be used with care in children with bodyweight above 8 kg. Upper adult endoscope (under 10 mm) or ultra‐thin colonoscope and ultra‐thin gastroscope (5.8 mm) are suitable for infants from 5 to 8 kg and under 5 kg respectfully.

More recently, image‐enhanced/magnifying colonoscopes have been developed, and their value in combination with dye spray or chromoendoscopy in various gastrointestinal diseases has been described (see Chapter 17). For instance, the decrease in the number of cryptal openings in ulcerative colitis can be observed and correlated to disease activity. Confocal colonoscopy is even more impressive in this regard (see Chapter 18) but this does not yet substitute for histologic assessment.

Informed consent and preprocedure preparation

Specific indications, risks and benefits of ileocolonoscopy must be the subject of a detailed discussion with the family. This should leave parents comfortable and confident about the need for and safety of the procedure before it is scheduled.

Ideally, both the child and parents should be offered a preparatory visit to the endoscopy unit to answer questions and defuse any potential concerns and anxieties regarding the procedure and admission. Younger children undoubtedly benefit from preadmission visits and the involvement of a play therapist to enable some understanding of what is to take place and why. Diagrams may help in explanations to older children. Preparatory online videos and child‐friendly cartoons from webpages such as www.paediatricgastroenterologist.co.uk and www.moviegi.com are very useful for informing the patient and parent regarding what to expect and should be made available. Units can benefit from devising a sample videos specific to their own facility.

It is now considered best practice to obtain informed consent at the planning clinic visit rather than on the day of the procedure – further confirmatory consent can be signed for on the day also.

On the day of the procedure, the child, and parents are invited to the preprocedure area. Here, the patient changes clothes and is prepared for intravenous line placement. To minimize the discomfort of a venipuncture, EMLA® cream is applied to one or two potential intravenous sites 60 minutes before the procedure. Infusion of age‐appropriate solution is started once the venous excess is established and secured. The patient is then transferred to the procedure area for the preparation of sedation or general anesthesia.

Specifics of sedation for colonoscopy

See Chapter 4.

Embryology of the colon relative to ileocolonoscopy

Abnormal rotation and fixation of the embryonic colon is probably the major reason for a “difficult” colon and incomplete colonoscopy.

A anticlockwise rotation around the superior mesenteric artery is the main mechanism of “packaging” the growing intestine in preparation for its return to the abdomen. Additional anticlockwise rotation is again crucial for proper relocation of the intestine into the peritoneal cavity.

As a result of a normal rotation, the colon acquires two zones of full fixation: the descending and ascending colon, as well as two areas of partial fixation: the cecum and rectum. In addition, the mobility of the splenic and hepatic flexure is somewhat limited by a phrenocolic and extension of the hepatorenal ligaments, respectively. Only the sigmoid and transverse colons possess their own mesentery and are fully mobile.

It is not surprising that they became a target of various endoscopic maneuvers preventing or minimizing stretching of these vulnerable segments of the intestine. It is easy to imagine that abnormal rotation or fixation of the embryonic colon can multiply difficulties in navigating through the unusually mobile bowel.

Some of the anomalies can be suspected during a procedure, for example, fixation of the cecum in the right hypochondrium. The intrinsic propensity of the embryonic colon for anticlockwise rotation from the left iliac fossa to the right gives an important clue to the concept of a torque steering technique of a colonoscopy.

Endoscopic anatomy of the colon and terminal ileum

The only dependable and observer‐reproducible anatomical landmarks in ileocolonoscopy are the anus, the appendiceal orifice, ileocecal valve, and terminal ileum. Everything between is guesswork! Many estimates of cecal intubation are incorrect due to confusion of the splenic or hepatic flexure with the cecum. Therefore, it is important to become accustomed to the nuances of endoscopic anatomy of the colon in order to achieve correct orientation during colonoscopy, accurate localization of lesions, and reassurance that the cecum has been reached.

The anal canal is less than 2 cm in a newborn, reaching an adult length of 3 cm by 4 years of age. It is normally closed due to tonic contraction of the anal sphincter but may be dilated in cases of chronic constipation or poor neurological control such as with spina bifida; beware that inference regarding possible sexual abuse is very difficult in a child under deep sedation or general anesthesia (Figure 12.1). It is important to remember that the axis of the anal canal is pointed anteriorly. Proper insertion of the colonoscope will minimize discomfort, eliminating excessive stretching of the anus and preventing embedding of the tip into the rectal mucosa.

The squamocolumnar junction or pectinate (dentate) line demarcates the proximal edge of the anal canal (Figure 12.2). A few longitudinal folds (columns of Morgani) run within the anal canal and terminate at the anal papillae (Figure 12.3). Occasionally, the anal papillae may be quite prominent, seen as cone‐like grayish structures. The rectum becomes enlarged and fusiform between the upper edge of the columns of Morgani and the rectosigmoid junction. This part of the rectum is called the ampulla. It is marked by three semilunar folds referred to as the valves of Houston (Figure 12.4). There are two such folds on the left and one on the right lateral wall. The ampulla narrows at the level of the rectosigmoid junction, which is distanced from the anal verge by 9 cm in neonates and 15 cm in children 10 years and older. The rectal mucosa is smooth and transparent, which allows good visualization of submucosal veins (Figure 12.5).

Multiple small lymphoid follicles in the rectal mucosa are normally present in infants and toddlers, but when excessive or surrounded by erythema they may indicate an allergic proctocolitis. The sigmoid colon is the most “unpredictable” part of the colon due to its long, “V”‐shape mesocolon. Stretching during colonoscopy could double the length of the sigmoid colon. Therefore, an absolute length of the sigmoid colon is not important unless it is tremendously elongated.

The mobility and displacement of the sigmoid colon may be limited due to previous surgery, adhesions or shortening of the mesentery.

A relatively small sigmoid colon in infants and toddlers has some disadvantages for the endoscopist: first, it decreases the threshold for pain due to activation of stretch receptors. Second, it limits application the of alpha loop maneuver and use of standard pediatric colonoscopes, making the procedure more technically challenging.

The normal sigmoid colon appears tubular because of the prominence of a circular muscle layer. The mucosa is less transparent than in the rectum. There are multiple circular folds throughout the sigmoid colon (Figure 12.6).

The taenia coli are not usually visible along the sigmoid colon except in the area adjacent to the sigmoid descending junction. The appearance of taenia coli in this area indicates significant stretching of the sigmoid colon.

During colonoscopy, the sigmoid colon is always stretched to some degree and becomes more spiral and twisted clockwise between the rectum and descending colon. The concave sacrum and a forward‐projecting sacral promontory determine the initial anterior deviation of the sigmoid loop. At this stage of the procedure, a colonoscope can be palpated easily unless the sigmoid colon is extremely stretched.

The transitional zone between the sigmoid and descending colon is located posterior at the level of the pelvic brim and out of reach for transabdominal palpation. The angle between the sigmoid and descending colon is sharper when the descending colon extends down below the pelvic brim due to an unusually low fixation and/or when the sigmoid colon was stretched out extensively (Figure 12.7).

Normally, the descending colon is slightly wider and more oval than the sigmoid colon (Figure 12.8). It runs straight up toward the left hypochondrium to join the splenic flexure. The mucosa of the descending colon is slightly grayish. The stems of the vessels run along folds, i.e., perpendicular to the lumen. The small branches cross the folds in parallel to the lumen (Figure 12.9). The folds of the descending colon are spread more apart relative to the folds of the sigmoid colon. The taenia coli are usually not visible. The splenic flexure is marked by the bluish color of the transilluminated spleen (Figure 12.10).

This area should occupy the right part of the lumen if the colonoscope was positioned properly inside the sigmoid and descending colon. The same color spot can be seen occasionally when the tip of the colonoscope is trapped within a very large sigmoid loop. Thus, this color mark does not definitively prove that the splenic flexure has been reached. The splenic flexure is firmly attached to the diaphragm by the phrenocolic ligament at the level of 10th and 11th ribs. That could explain occasional hiccups and transient hypoxia during exploration of the transverse colon due to excessive pressure and irritation of the phrenic nerve, especially in infants and young children.

The junction with the transverse colon is located along the upper aspect of the medial wall of the splenic flexure. It is angled by the mobile transverse colon, which hangs down from the elevated splenic flexure. The area is more sharply angled and even folded when the patient is in the left lateral position (Figure 12.11).

Relatively thin circular and thick longitudinal layers of the muscularis propria are responsible for the triangular shape of the transverse colon (Figure 12.12). The slope of the transverse colon is pointed toward the hepatic flexure, which is more voluminous than the adjacent colonic segments and has a blue‐gray color acquired from the neighboring liver (Figure 12.13). The folds become circular at both ends of the hepatic flexure. The junction with the ascending colon is located higher than the adjacent transverse colon. It points toward the right lobe of the liver and is sharply angled posteriorly (Figure 12.14). The area between the hepatic flexure and the ascending colon is always hidden in the right upper corner of the screen behind the mucosal fold. Steering of the shaft anticlockwise, pulling it back, and elevation of the tip help to stretch the folded lumen. Subsequent clockwise rotation and deviation of the tip to the right and decompression of the colon facilitate exploration of the ascending colon.

The ascending colon is a short (5 cm in some young children), retroperitoneal and fixed segment of the right colon. It runs between the cecum anteriorly and the lower pole of the right kidney posteriorly. The lumen of the ascending colon is usually wide open. It extends into the cecum, a “blind” pouch outlined by the ileocecal valve at the top and the appendix orifice (the landmark of the cecum) at the bottom.

• the ileocecal valve
  
• the appendiceal orifice
  
• the triradiate fold.

The appendiceal orifice is usually oval or rounded and located at the intersection of the taenia coli at the cecal pole. The orifice can be thought of as a “bow” with an imaginary arrow pointing to the ileocecal valve (IV): “bow and arrow sign” (Figure 12.15). The IV is usually “hiding” on the upstream or “cecal” slope of the ileocecal fold but can be discovered by a focal bulging or widening of the medial aspect of the fold (Figure 12.16).

Torque steering technique – the key to successful ileocolonoscopy

A unique colonoscopy technique has been developed to overcome the high flexibility, elasticity, and multiple angulations of the large intestine (the sigmoid colon in particular).

It consists of two types of maneuver: loop prevention‐torque steering and loop reduction.

The main principles of the torque steering technique are (i) substitution of lateral angulation control for torqueing the shaft clockwise or anticlockwise with the preceding up‐and‐down deflection of the bending section and two‐corkscrew maneuvering around a sharply angled segment of the colon instead of application of linear force to push the endoscope forward (note that this technique works only when the shaft is straight).

A key element of the loop reduction technique is a combination of simultaneous clockwise or anticlockwise rotation and puling the shaft back, as explained below.

One important” trick” in learning ileocolonoscopy is to grasp the concept of the lumen as a clock face and the tip of the scope as a short hour hand. A simple angulation of the tip up or down is sufficient to reach the 12 or 6 o’clock sites. However, vertical angulation alone will not work if the target is anywhere on the left side of the dial (between 12 and 6 through 9 o’clock) or the right side (between 12 and 6 through 3 o’clock). In this case, lateral deflection can be achieved by the shaft torque to the left/anticlockwise or to the right/clockwise direction with the tip deflected up or down respectively (Figure 12.17). This approach, which is the core of the torque steering technique, provides the best spatial orientation and control of the colonoscope by the left thumb and middle finger and “winding”‐rotating the shaft up to 360° by the thumb, index, and middle fingers of the right hand.

Torque steering is the most important skill to acquire in the early days of a colonoscopist’s career, especially in the rectosigmoid colon. Such skill acquisition and employment will markedly diminish the possibility of sigmoid loop formation.

Golden rules of ileocolonoscopy

1. Do not advance unless you know where the lumen is. Pushing blindly is useless and dangerous.
   
2. The direction of the luminal axis should be ascertained before pushing in.
   
3. Think before advancing the scop: each bend requires a conscious steering decision.
   
4. When searching for the lumen, the view must be clean; delicate insufflation and slow withdrawal with clockwise and anticlockwise rotation can help to identify the dark crescent which is nearest to the lumen.
   
5. Check scope for neutral position when in doubt of orientation.
   
6. Insufflate as little as possible: excessive air, especially in the sigmoid colon, makes it elongated and tortuous. The rule of insufflation is “as much as necessary, as little as possible.”
   
7. Suction out excess air frequently to make the colon shorter and easier to navigate.
   
8. Suction fluid infrequently, only when it is necessary to clear the view.
   
9. Steer carefully and cautiously: initiate each angulation and torque slowly to be able to terminate the maneuver almost immediately if the tip is moving in the wrong direction.
   
10. Pull back frequently for shortening of the sigmoid colon and loop prevention.
    
11. Corkscrew around acute bends instead of pushing up against them.
    
12. Avoid forceful angulations of the bending portion while advancing the scope.
    
13. Avoid blind “slide‐by” over the mucosa insertion for more than a few seconds. This maneuver is permissible as a last resort and if the scope slides easily over the surface with a clear view of the “slide‐by” mucosal vascular pattern.
    
14. Change patient position when needed.
    
15. If you are stuck for more than 2–3 minutes, then change something – patient position, abdominal pressure, antispasmodic administration; do not just keep pushing and hoping!