27
Endoscopy
INTRODUCTION
Flexible upper gastrointestinal endoscopy is the principal method for the evaluation and treatment of a wide range of conditions of the esophagus, stomach, and duodenum. With advances in equipment and technology over the last 50 years, complete visualization of the upper gastrointestinal tract mucosa can be achieved, with targeted tissue sampling and therapeutic intervention (dilatation, polypectomy, endoscopic ablation/resection, stent insertion) being performed as necessary. Flexible endoscopy has largely replaced rigid endoscopy and contrast radiology as the first-line investigation of choice. While the basic controls have changed little over the years, digital technology with high resolution imaging and magnification means that the modern endoscope differs markedly from the early flexible fiberscopes of the 1960s. Still images and videos can be captured easily and training is enhanced by all parties viewing the procedure on the same screen.
Surgeons have been influential in the developments of endoscopic assessment of the upper gastrointestinal tract, but in certain countries around the world they have now relinquished this role to their medical gastrointestinal colleagues. However, esophagogastric and thoracic surgeons have an increasing incentive to ensure that endoscopic techniques, both diagnostic and therapeutic, are integral to their surgical practice. Advanced endoscopic treatment for achalasia, gastro-esophageal reflux disease, and obesity are emerging and are beginning to compete with the more traditional surgical methods of treatment. There is also an increasing role of combining endoscopic visualization intraoperatively during certain operations to improve the outcome of surgical therapy. Surgeons need to reengage with this domain to the benefit of their patients.
This chapter summarizes the indications, techniques, and uses of upper gastrointestinal endoscopy. Modern assessment of the esophagus is not carried out as an isolated procedure and is performed in conjunction with assessment of the stomach and duodenum. However, in this chapter, we focus on the esophagus and the gastro-esophageal junction (GEJ) and uses of flexible endoscopy directly relevant to esophageal surgeons.
RIGID ESOPHAGOSCOPY
The need for rigid esophagoscopy is rare. Achieving profi ciency with this technique is difficult nowadays. Figure 27.1 shows rigid esophagoscopy equipment—esophagoscopes (A), biopsy forceps (B), and suctioning devices (C). Its main disadvantages are that general anesthesia is required, it is technically difficult in patients with restricted cervical mobility, and there is a small rate of perforation. By comparison, the risk of perforation with diagnostic flexible esophagoscopy is negligible. When lesions are at or close to the upper esophageal sphincter, visualization and biopsy can be easier with a rigid endoscope, where a combination of general anesthesia to eliminate swallowing and a greater instrument diameter can be helpful. While some surgeons maintain that the removal of large impacted foreign bodies can be easier with a large bore rigid tube and appropriately sized grasping forceps, the wide range of instrumentation designed for use with flexible endoscopes and a semirigid overtube has largely superseded the rigid procedure.
27.1 Rigid esophagoscopy equipment.
Under general anesthesia, the patient is placed supine on an operating table where the head end of the table can be adjusted. The esophagoscope should be checked and connected to the light cable. An adequate length suction device and biopsy forceps should be available on a tray beside the surgeon. The upper teeth are protected by a gum guard. The surgeon holds the rigid esophagoscope in the right hand while the left stabilizes the patient’s mandible and protects the teeth. During insertion of the scope, the head is initially held forward in the “sniffing” position while the scope is placed to the left side of the oropharynx (see Figure 27.2 ). The epiglottis is visualized and pushed out of view by the beak of the endoscope. Once the cricopharyngeus is passed, the head is extended to eliminate the angle of the mouth and pharynx, and the endoscope gently enters the esophagus (see Figure 27.3 a through c). The esophagus can then be examined under direct vision.
27.2
27.3a—c
FLEXIBLE UPPER GASTROINTESTINAL ENDOSCOPY
Indications
Table 27.1 indicates the common reasons for flexible endoscopic assessment of the esophagus. It is clearly indicated in patients complaining of dysphagia, odynophagia, and persistent heartburn, or those with an abnormal contrast study or computed tomography (CT) scan, or who have other symptoms suspicious of esophagogastric cancer. However, its role has vastly expanded to include uses in the therapeutic, intraoperative, postoperative, and surveillance settings.
Table 27.1 The indications for flexible examination of the esophagus
Upper gastrointestinal endoscopes
A wide variety of endoscopes of different types, lengths, and diameters are available (see Figure 27.4 , which shows a thin gastroscope [A], standard gastroscope [B], side-viewing duodenoscope [C], linear endoscopic ultrasound [EUS] scope [D], radial EUS scope [E], and therapeutic double channel gastroscope [F]). The endoscopist should ensure that the type used matches the intended procedure.
27.4 Range of different endoscopes available.
Modern standard endoscopes are designed to be placed transorally and have an approximate diameter of 10 mm with a 2.8 mm or greater working channel. The basic features (channels for insufflation, suction, and biopsy) and controls (up/down, right/left tip deflection) have changed little over the years. With the exception of echoendoscopes and duodenoscopes, all are forward viewing, with the image captured on a chip at the tip of the endoscope, rather than transmission via fiber-optic cables. The most advanced scopes come with high definition, zoom, or narrow band imaging settings. The working channel allows insertion of an array of accessories, including biopsy forceps, snares, injection needles, guide wires, and balloon dilators. Unlike colonoscopes, which have some degree of torque along the shaft so that the instrument can be rotated by twisting, the shorter endoscopes used in the upper gastrointestinal tract are most easily rotated by the operator’s body position and hands rather than attempting to twist the endoscope.
Ultrathin endoscopes (less than 6 mm diameter) can be passed in the unsedated patient transnasally. There is some evidence they may be better tolerated in some patients. These narrow diameter scopes are particularly useful to negotiate tight esophageal strictures, avoiding the need for dilatation and allowing precise evaluation of the length and nature of the stricture. The working channel, however, is only about 2 mm in diameter and biopsies are therefore small. Nasendoscopy has limited therapeutic value because of the small channel, but it can be used to negotiate strictures so that a guide wire can be placed safely, prior to a therapeutic maneuver. Endoscopes with two working channels (dual channel endoscopes) are useful for therapeutic work including endoscopic resections and for the control of upper gastrointestinal bleeding.
Flexible endoscopy technique
Most endoscopies are performed as outpatient procedures either with conscious sedation (usually achieved with a shortacting benzodiazepine) or local anesthetic throat spray. Pulse, blood pressure, and oxygen saturation should be monitored throughout the procedure. Patients are prepared for endoscopy by being nil by mouth for 6 hours, although this may need to be extended in patients with chronic obstructive symptoms, such as suspected achalasia or delayed gastric emptying. Examination should include the entire gastrointestinal tract as far as the second part of the duodenum, even when symptoms seem confined to the esophagus.
The most common position for the examination is the left lateral decubitus, with the neck flexed. Under general anesthesia, the patient can be supine and intubation aided by the anesthetist providing a chin lift. A dental guard is used to protect the endoscope, which is passed under direct vision over the tongue to the back of the oropharynx where the epiglottis and larynx are visualized. Slight neck flexion and an instruction to swallow, while maintaining the endoscope in the midline, will allow the endoscope to pass the cricopharyngeus and into the cervical esophagus. Gentle pressure only should be used and particular care taken in elderly patients who potentially have cervical osteophytes or symptoms suspicious of a pharyngeal pouch.
The endoscope is advanced under direct vision with gentle air insufflation to provide an optimal view. Minor indentations into the esophageal wall can occur at the level of the aortic arch and left atrium, but the critical landmark is identification of the GEJ that is usually about 40 cm from the incisor teeth (see Figure 27.5 ). Under normal circumstances, this is also the squamocolumnar junction and is easily identified as a Z-shaped line of demarcation between the pale pink squamous esophageal mucosa and the redder columnar lining of the stomach. This junction can be difficult to identify in the presence of a hiatus hernia or when the lower esophagus is covered by a columnar epithelium (Barrett’s esophagus). The most useful visual clue is careful inspection of the mucosal vascular pattern, which, in the lower esophagus, has a characteristic palisaded appearance. The termination of gastric folds is less reliable. Detailed endoscopic examination is best performed as the instrument is withdrawn, and it is therefore preferable to reach the duodenum with insufflation and minimal use of suction unless a large fluid residue is a problem. This avoids mucosal suction artifact, reduces the risk of the endoscope looping in a very dilated stomach, minimizes patient discomfort, and facilitates maneuverability.
27.5 Landmarks of the esophagus at endoscopy.
The duodenal bulb (which has no circular folds) is inspected. The scope is angled right and upward and rotated 90 degrees clockwise to enter the second part of the duodenum. While views of the distal duodenum can be obtained, it is only necessary if there is a clinical reason to do so. The papilla of Vater is not easily viewed using an end-viewing gastroscope. The scope is withdrawn through the pylorus. The stomach is inflated so that the rugal folds are flattened out and full mucosal views can be obtained. The antrum and body are examined withdrawing the scope in a spiral fashion on careful withdrawal. Identification of the incisura angularis is a useful landmark. Retroflexion of the scope allows visualization of the fundus and cardia. Lesions are mapped, biopsied as necessary, and conventionally both anatomic location and a measurement from the incisor teeth, as indicated by markings on the shaft of the endoscope, are described. Care should be taken with the measurements to ensure that the endoscope is straight and most of the stomach is deflated before complete withdrawal from the stomach (residual air should be removed to ensure the patient is comfortable after the procedure). The esophagus is then also assessed during withdrawal.
BIOPSY TECHNIQUE AND RECOMMENDED NUMBER OF SAMPLES
The “turn and suction” technique of endoscopic biopsies allows better acquisition of larger mucosal samples to aid in histological diagnosis. The biopsy forceps are advanced into the lumen, opened, and then withdrawn backward to be close to the tip of the endoscope. The endoscope tip is then turned gently into the wall of the esophagus and the suction button is depressed to suck the mucosa into the biopsy forceps, which are then closed. After the endoscope is straightened and air introduced to the lumen, the biopsy can be taken by pulling the forceps and avulsing the mucosal sample. This technique is especially useful for Barrett’s surveillance biopsies. The recommended number of biopsy samples obtained for different esophageal conditions are shown in Table 27.2 . It is particularly important in malignancy to ensure adequate numbers of biopsies are taken so that an accurate histological diagnosis is made on the first endoscopy. Increasingly, immunohistochemical tests may be required both for diagnostic purposes (gastrointestinal stromal tumors [GIST]) and to guide therapy (human epidermal growth factor receptor 2 [HER-2]).
Table 27.2 Recommended biopsy schedule for esophageal pathology
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