Learning Examination Technique

Learning colonoscopy technique requires motivation, manual dexterity, concentration, and patience on the part of the trainee. Already practiced in the technique of endoscopically examining the upper digestive tract, the beginner will learn about similarities and differences related to using a gastroscope vs. using a colonoscope.

■ Instrument Features

All endoscopes can be divided into three sections: the insertion tube, which is advanced in the patient, the instrument control head, where the physician can maneuver the endoscope tip and has access to the water/air supply and the instrument channel and, finally, the universal cord and plug, which connect the instrument to the supply unit (Fig. 2.1).

Insertion tube. The insertion tube of the video colonoscope consists of a ca. 130-cm-long tube containing optical fibers, digital wires, air and water nozzles, the instrument channel, and Bow-den cables for better mobility.

Located at the tip of the endoscope are the lens and video chip, which produces the image (Fig. 2.2).

The last 15 cm of the insertion tube are especially flexible and can bend in all four directions, allowing better maneuvering in the gastrointestinal tract. The degree of flexion of the colono-scope is 180° up/down and 160° to the right/left. Compared with the colonoscope, the gastroscope can be moved to a greater degree upward, but to a lesser degree in all other directions (Figs. 2.3, 2.4, Tab. 2.1).

Lens with lens cover

Fig. 2.1 Main parts of the colonoscope.

A Universal cord and plug, B Instrument control head, C Insertion tube (courtesy of Mr. Wirth, photo archive, Augsburg Clinic).

Lens with lens cover

Fig. 2.1 Main parts of the colonoscope.

A Universal cord and plug, B Instrument control head, C Insertion tube (courtesy of Mr. Wirth, photo archive, Augsburg Clinic).

/Air/water spray nozzle

Auxiliary water channel

Light guide

Opening to instrument channel

Fig. 2.2 Tip of colonoscope (courtesy of Mr. Wirth, photo archive, Augsburg Clinic).

/Air/water spray nozzle

Auxiliary water channel

Light guide

Opening to instrument channel

Fig. 2.4 Comparing the outer diameters of the distal end of a colonoscope (left) and a gastroscope (right) (courtesy of Mr. Wirth, photo archive, Augsburg Clinic).

Fig. 2.4 Comparing the outer diameters of the distal end of a colonoscope (left) and a gastroscope (right) (courtesy of Mr. Wirth, photo archive, Augsburg Clinic).

Endoscope Distal End Movement

Table 2.1 Comparing standard video endoscopes (example: Olympus)

Table 2.1 Comparing standard video endoscopes (example: Olympus)

Standard video endoscopes

Colonoscope

Gastroscope

Maximum angling

Up 180°

Up 210°

Down 180°

Down 90°

Right/left 160°

Right/left 100°

Outer diameter, distal end

12.8 mm

10.2 mm

Length of insertion tube

133 cm

103 cm

Angle

140°

130°

Fig. 2.5 Control head of a video colonoscope:

1 Function buttons, e.g., video recorder remote control

2 Freeze button

3 Suction button

4 Air/water button

5 Instrument channel

6 Locking device

7 Angling wheel (right/left)

8 Angling wheel (up/down)

(Courtesy of Mr. Wirth, photo archive, Augsburg Clinic.)

The sigmoidoscope measures only 60 cm in total length. Because of its high degree of maneuverability, it is sometimes used in patients where the indications for examination are limited to the sigmoid colon and rectum.

Different colonoscope models can vary in length, outer diameter, and width of the instrument channel.

Instrument control head. The functions necessary for maneuvering the tip the endoscope, for suction, cleansing, and air insufflation are all located on the control head. (Fig. 2.5).

The opening to the instrument channel is somewhat below the air/water cylinder, but before the air/water channel merges with the suction channel. The diameter of the inside of the instrument channel is between 2.8 mm and 3.7 mm, allowing the insertion of endoscopic accessories such as biopsy forceps or polypectomy snares (Fig. 2.6).

Video endoscopes also have remote control buttons that, according to model, may have various functions. These buttons can generally be used for freeze frames, video recording, printing, and adjusting illumination intensity (peak and average). Newer generations are equipped with so-called big chips that allow the projection of a high-resolution screen-size image onto a video monitor. The image can be digitally enhanced using modern image processing technology (e.g., Olympus CV-160) for structure enhancement, variable by several levels during and even after the examination (see Chapter 3).

Universal cord. The universal cord connects the endoscope to the light source, air supply, water supply, suction pump, and video processor. The video processor transmits the image to the monitor screen on the video tower (Figs. 2.7-2.10).

■ Operating the Endoscope

Before every examination, the suction, cleansing, and air insufflation functions on the endoscope must be checked and the "white balance" set on the video processor. The physician's left hand holds the control head of the endoscope while the right hand moves the insertion tube or controls fine adjustment of the outer angling wheel on the control head (Fig. 2.11).

Suction and cleansing. The index finger of the left hand can be used to depress the suction button while the middle finger can either press the air/water button lightly for insufflation or more firmly to activate the washing system (Fig. 2.12).

Colonoscopy And Injection Tube

Fig. 2.7 Universal plug on an endoscope

(courtesy of Mr. Wirth, photo archive, Augsburg Clinic).

Forceps Channel Video Colonoscope
Fig. 2.6 Colonoscopy accessories (from left to right): biopsy forceps, clip applicator, injection needle, and polypectomy snare (courtesy of Mr. Wirth, photo archive, Augsburg Clinic).

Fig. 2.7 Universal plug on an endoscope

(courtesy of Mr. Wirth, photo archive, Augsburg Clinic).

Fig. 2.8 Plugging the universal cord into the processing unit (courtesy of Mr. Wirth, photo archive, Augsburg Clinic).

Fig. 2.11 Operating the instrument.

a The examiner's right hand guides the tube or b Fine adjustment of the endoscope tip by moving the angling wheel. (Courtesy of Mr. Wirth, photo archive, Augsburg Clinic.)

Colonoscopy Clip

Fig. 2.11 Operating the instrument.

a The examiner's right hand guides the tube or b Fine adjustment of the endoscope tip by moving the angling wheel. (Courtesy of Mr. Wirth, photo archive, Augsburg Clinic.)

Endoscopy Circuit Diagrams

Flexion. Two wheels control the angling of the endoscope in different directions. Using the thumb of the left hand, the large wheel can be turned to move the tip of the endoscope up or down while the smaller wheel directs the tip of the endoscope right and left (Figs. 2.13,2.14, Tab. 2.2). Each wheel has a locking device so that it can be fixed in one position, allowing, for example, the right hand to remain free to use the instrument channel (Fig. 2.15).

Advancing the endoscope. In an experienced and well-coordinated team, the assistant can advance the insertion tube in the colon while the physician uses both hands on the control head to steer the tip of the endoscope (Fig. 2.16). However, some examiners prefer to advance the shaft themselves in order to better feel the position of the instrument. In this case, the right hand is used only for fine adjustments using the angling wheels on the head of the endoscope (Fig. 2.17).

Gastrointestinal Endoscopy Wheels

Fig. 2.13 Moving the large angling wheel.

a Downward. b Upward.

(Courtesy of Mr. Wirth, photo archive, Augsburg Clinic.)

Fig. 2.13 Moving the large angling wheel.

a Downward. b Upward.

(Courtesy of Mr. Wirth, photo archive, Augsburg Clinic.)

Technique Sigmoid Colon Compression

Fig. 2.14 Moving the endoscope tip corresponding to the maneuvering of the large angling wheel. a Upward (cf. Fig. 2.13 a). b Downward (cf. Fig. 2.13 b) (courtesy of Mr. Wirth, photo archive, Augsburg Clinic).

Fig. 2.15 Inserting biopsy forceps into the instrument channel (courtesy of Mr. Wirth, photo archive, Augsburg Clinic).

Fig. 2.14 Moving the endoscope tip corresponding to the maneuvering of the large angling wheel. a Upward (cf. Fig. 2.13 a). b Downward (cf. Fig. 2.13 b) (courtesy of Mr. Wirth, photo archive, Augsburg Clinic).

Fig. 2.15 Inserting biopsy forceps into the instrument channel (courtesy of Mr. Wirth, photo archive, Augsburg Clinic).

Table 2.2 Maneuvering the endoscope tip using the angling wheels

Rotation of the angling wheel

Movement of the endo-

scope tip

Large wheel: toward examiner

Raises the tip

Large wheel: away from examiner

Lowers the tip

Small wheel: toward examiner

Turns the tip to the left

Small wheel: away from examiner

Turns the tip to the right

■ Simulators

Maneuvering the endoscope and manual technique. The novice must first take time to study the functions of the endoscope. It is important to practice instrument handling before performing the first examination on a patient. The development of three-dimensional computer simulation can enable the trainee to practice maneuvering the endoscope and to develop the necessary manual dexterity (Figs. 2.18, 2.19).

According to one study evaluating usage of the Simbionix system, two hours of practice per day for three weeks are necessary in order for a novice to approach the level of handling expertise of an experienced endoscopist (6). Depending on the computer program, the virtual endoscopy simulator can simulate normal and pathological findings in the colon, helping to improve later detection of pathologies on actual patients.

Therapeutic interventions. Even though therapeutic interventions can now be computer simulated, experts agree that computer-simulation training of the novice endoscopist can offer only limited improvement in technique and skill; an actual examination situation is much more complex due to differences in mucosal properties and physiological factors. Thus, costly animal models are used in some courses aimed at maintaining en-doscopic competency, with small groups practicing specific techniques (e.g., hemostasis) under more realistic conditions. The EASIE concept developed in Erlangen, Germany, is an animal-part simulator that integrates organs from a slaughterhouse into the model and, using perfusion, simulates in-vivo en-doscopic interventions (7) (Fig. 2.20).

Fig. 2.16 The assistant advances the endoscope (courtesy of Mr. Wirth, photo archive, Augsburg Clinic).

Fig. 2.17 The physician advances the endoscope (courtesy of Mr. Wirth, photo archive, Augsburg Clinic).

Simulatore Endoscopia Simbionix

Fig. 2.18 Simbionix computer simulator

(courtesy of Simbionix).

Fig. 2.19 Virtual training (courtesy of Simbionix). a Manual skill training. b Virtual colonoscopy using a simulator.

Fig. 2.18 Simbionix computer simulator

(courtesy of Simbionix).

Fig. 2.19 Virtual training (courtesy of Simbionix). a Manual skill training. b Virtual colonoscopy using a simulator.

■ Training on a Patient

Observation. Despite modern computer-assisted learning techniques, observing while an experienced endoscopist performs colonoscopy is a key part of training for the beginner. It is important that the explanation by the endoscopist is suited to the trainee's level of training and that the handling of the instrument in technically difficult situations is described. An expert description of pathological findings enables the student endos-copist to better identify pathologies already seen in textbooks.

Withdrawing and advancing the instrument. The first practical exercise to be performed on the patient is withdrawing the instrument from the cecum to the rectum, taking care that all segments are sufficiently visualized. The next objective is to learn how to advance the instrument to the cecum. For this step, the trainer advances the shaft while the student operates the control head. Only after advancement to the cecum can safely and successfully be performed should training begin for intubating the Bauhin valve (Tab. 2.3).

Simple and complex interventions. Simple interventions such as performing a forceps biopsy, removing small polyps, and performing hemostasis by injection should be mastered before per-

Table 2.3 Steps in colonoscopy training on a patient

Steps Objective of basic colonoscopy training

1 Observe examination procedure

2 Withdraw the instrument from the cecum to the rectum

3 Advance the instrument to the cecum under the guidance of an experienced endoscopist

4 Advance the instrument to the cecum under supervision, but without direct assistance

5 Intubation of the Bauhin valve

6 Interventions: forceps biopsy, removal of small polyps, simple hemostasis forming colonoscopy without supervision, in order to spare the patient an unnecessary further examination.

More complicated maneuvers, such as the removal of larger or sessile polyps, the use of clip applications, dye spraying techniques, performing mucosectomies, balloon dilations, or bou-gienage, are only performed after acquiring sufficient experience in basic technique, e.g., during gastroenterological training. Training centers such as CCEPDT (Competence Centers in Education, Procedure Development, and Training), for example, offer quality-controlled courses taught by skilled endos-copists experienced in teaching (7).

Constipation Prescription

Constipation Prescription

Did you ever think feeling angry and irritable could be a symptom of constipation? A horrible fullness and pressing sharp pains against the bladders can’t help but affect your mood. Sometimes you just want everyone to leave you alone and sleep to escape the pain. It is virtually impossible to be constipated and keep a sunny disposition. Follow the steps in this guide to alleviate constipation and lead a happier healthy life.

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