TSRA Content:
Author: Kenneth Holt, MD
This is a revision and update from the previous edition of the TSRA Primer in Cardiothoracic Surgery written by Ryan Mack, MD
Introduction
Flexible upper endoscopy or esophagogastroduodenoscopy (EGD) has come a long way from its inception in the 1950s and now serves as an essential diagnostic and therapeutic tool in the management of esophageal/foregut disease. Thoracic surgeons must be facile with the techniques used to perform upper endoscopy and adjunctive interventions, as well as be familiar with the terminology used to properly describe pertinent findings.
Indication
As critical as the technical skill required to perform any procedure is the knowledge of when to perform said procedure. While the list of indications is vast for upper endoscopy, we will only discuss a few of the most pertinent to thoracic surgeons. The most obvious is the evaluation and biopsy of esophageal/proximal stomach masses. Other common reasons thoracic surgeons perform upper endoscopy include dysphagia and odynophagia. While there are many causes of dysphagia and odynophagia, the main branching point in therapy from a surgical perspective is whether these symptoms are secondary to malignancy or a benign process.
Preparation
Patients are typically directed to be nil per os (NPO) at midnight before the exam, though no clear liquids 4-6 hours before is often long enough. Patients with motility disorders (i.e. achalasia) may need to abstain from solid foods for a longer period to avoid retained food debris that would compromise the exam. If there is a concern for incomplete emptying of the stomach, sometimes metoclopramide or erythromycin are given as a prokinetic agent beforehand. Prophylactic antibiotics are not typically required. If extensive biopsies or endomucosal resection is anticipated, consideration should be given to discontinuing anticoagulation/antiplatelet therapy. Previous endoscopy and pathology reports should be reviewed beforehand. Past medical history should also be reviewed and may give a clue as to whether the patient is suitable for conscious sedation rather than general anesthesia.
When a patient presents with dysphagia, it is advisable to obtain a preoperative barium esophagram and/or upper gastrointestinal series to identify any potential pathology that would increase the risk of perforation, such as a tight stricture, obstructing tumor, or diverticulum.
An EGD can be a quick procedure that yields high diagnostic and therapeutic value when done properly. Having a systematic approach as well as being prepared avoids unnecessary delays. Before the patient enters the room, the endoscope should be investigated. The insufflation, suction, irrigation, and wheel mechanisms should all be inspected. A malfunctioning scope should be replaced. To become a skilled endoscopist, it is essential to learn how to set up the endoscope in its entirety, this will be particularly useful when troubleshooting problems as they arise. Monitors should be placed in the appropriate position and made sure to be transmitting images from the endoscope. The scope should be white-balanced. Once the endoscope is set, equipment needed for adjunctive procedures should be in the room readily available for use. This includes irrigation, lubricant, and specimen collection supplies. It may be necessary to have a pediatric endoscope available if a tight stricture or large tumor is anticipated. If dilation or stenting is planned, fluoroscopy should be on call to the room and lead should be available. Be sure to familiarize yourself with the dilators at hand; not all institutions have the same style of dilators. Biopsy forceps should be available for all upper endoscopies. Additional equipment and personnel may be needed for more advanced endoscopic techniques, such as EMR, ESD, RFA, PDT, etc., and appropriate arrangements should be made.
Procedure
Patient positioning is dependent on the type of anesthesia to be performed. The patient should be positioned supine if the procedure is to be performed under general anesthesia. If conscious sedation is to be used, the slight left lateral decubitus position is advised. It is helpful to pad the head and tuck the chin toward the chest if the patient is to be sedated. Any desaturation, hemodynamic instability, or intolerance on the part of the patient should prompt repositioning and intubation. Bite blocks can be inserted just before sedation begins or after depending on anesthesia/endoscopist preference. A topical anesthetic may be used to minimize gagging in awake patients.
The endoscopist stands at the head of the bed, facilitated by turning the operative table 90 degrees. The scope is held in the palm of the left hand and the thumb is used to turn the large (anterior/posterior flexion) and small wheels (controlling right/left flexion). The index finger controls the upper suction button, and the middle finger controls the lower insufflation/irrigation button. It is important to avoid excessive insufflation prior to esophageal/foregut procedures to prevent small bowel distension, as this can limit visibility during laparoscopy.
Several techniques are feasible for inserting the scope, leaving it to the endoscopist’s preference. The endoscope can be inserted blindly or under direct vision. It is helpful to lubricate the distal end of the scope to facilitate the smooth passage of the scope on insertion. Avoid lubricating where the right hand is manipulating the scope. The blind technique should be avoided in patients with proximal esophageal pathology (i.e. Zenker's, anastomotic leaks/strictures), as this technique will increase the risk of perforation. Keep in mind the three most common sites of perforation are the three sphincters you will traverse: the upper esophageal sphincter (UES), lower esophageal sphincter (LES), and the pylorus; therefore, special care should be taken when passing through these orifices.
With the blind technique, some prefer to rest the scope on the left shoulder while the left hand lifts the mandible, and the right hand inserts the scope. Others prefer to hold the scope in the left hand and insert it with the right hand, while anesthesia provides a gentle chin lift. The latter technique is particularly useful when in the supine position. If under general anesthesia, it may help to have the anesthesiologist lift gently on the endotracheal tube (ETT) to prevent the trachea from compressing the esophageal lumen. The right hand introduces the scope into the mouth along the right gutter and the scope is advanced similarly to the placement of an orogastric tube; often clockwise rotation of the scope helps ease the scope past the UES. This should be done gently, and any resistance should prompt abandoning of the blind technique. Inserting the scope under direct vision is safest and preferred by most surgeons. A slight anterior bend is given to the scope for insertion (thumb down) into the mouth, advancing over the tongue and into the hypopharynx. The vocal cords or ETT should be seen anteriorly and once the epiglottis is passed, the scope is straightened (thumb up).
The right hand initially grasps the scope about 20-25 cm from the tip, palm down, between the index and thumb. Some endoscopists prefer to hold the scope with a dry rag or gauze. The right hand is used to advance, withdraw, and rotate the scope. Additional degrees of rotation can be obtained by swinging the left hand holding the endoscope across the chest toward the right shoulder or in an arc 180 degrees in the opposite direction. For upper endoscopy, the small wheel controlling the left and right movements of the tip of the scope is often utilized less and the scope is manually rotated with the right hand. When accompanied by the use of the large wheel, this is often all that is required to perform an EGD in its entirety.
Awake patients may be asked to swallow to facilitate passage beyond the epiglottis and UES. Some find it easiest to intubate the proximal esophagus by advancing the scope into the left arytenoid recess by giving the scope a slight anterior bend (thumb down) and rotating to the left (counterclockwise) with the right hand. The scope is advanced slightly and then rotated back to the right (clockwise). Small puffs of insufflation should reveal the lumen and the scope is straightened (thumb up) and advanced into the proximal esophagus with gentle pressure to pass the UES. All movements should be small and controlled. If difficulty is encountered on the left, try the contralateral side. The esophagus is examined first in a proximal to distal fashion. The scope is then advanced into the stomach and through the pylorus. The duodenum and stomach are examined distal to proximal by slowly withdrawing the scope. The exam is completed by retroflexion of the scope to examine the cardia and LES function. Biopsies or therapeutic measures can be carried out during the stepwise exam or following the complete examination.
Findings
To be an effective endoscopist, one must be able to identify and effectively communicate the location of normal landmarks and abnormal pathology. When describing these findings, the incisors are used as the reference point. Important landmarks that can be easily confused or omitted in a report by the novice endoscopist include the squamocolumnar junction (SCJ), the gastroesophageal junction (GEJ), and the crural pinch. The location and relationship of these landmarks will help to clarify the pathology that is present and serves as a reference point when discussing other findings.
In a normal patient, the SCJ (aka Z-line) will be located at around 35-40 cm from the incisors and will have a regular, even appearance of transition from the pale, pink esophageal mucosa to the red, darker mucosa of the stomach. The GEJ is located at the most proximal point of the gastric folds. It is important to avoid excessive insufflation and flattening of the folds making it difficult to distinguish the GEJ. The crural pinch is located where the diaphragm narrows around the distal esophagus (or stomach in the case of a hiatal hernia) at the hiatus. In a normal patient, these landmarks will all be roughly located at the same point. If the GEJ is noted to be more proximal than the crural pinch, a hiatal hernia is present, and the size of the hernia is noted as the distance from the GEJ to the crural pinch. An irregular Z-line or salmon-colored mucosa that extends more proximally than the GEJ is indicative of Barrett's esophagus. The location of any anastomoses should be reported and any breakdown or stricturing should be described in terms of circumference and length.
The list of abnormalities that can be encountered during upper endoscopy is beyond the scope of this chapter. However, provided is a summary of common findings and descriptors that may serve as a useful reference (Gallery 1). All abnormalities should be biopsied unless excessive bleeding is anticipated. It is also helpful to be familiar with commonly used classifications used by endoscopists, developed to standardize the description of commonly encountered pathology. Details of some common grading systems are also listed in Gallery 1. Gallery 1 serves as a starting point for common findings and grading systems but is by no means a comprehensive list.
Biopsy
Biopsies are a key part of any upper endoscopy; this is particularly true of endoscopies performed by thoracic surgeons. Thus, a brief word about biopsy is warranted, as it is a key part of upper endoscopy. Once the scope is positioned in the middle of the lumen with ample space for safe passage, the endoscopic forceps are passed through the working port in a controlled fashion with the right hand until the jaws of the forceps are seen just beyond the tip of the scope. This method allows the forceps to be passed safely into the lumen. When biopsying the esophagus, it is safest to bring the forceps out of the scope with the tip in the insufflated stomach and then to withdraw the scope and forceps together to the point of interest. The scope is then positioned to bring the forceps into apposition with the abnormality. The assistant is directed to open the jaws and the forceps are advanced into the lesion. The jaws are closed and with a quick snap, the forceps are withdrawn and removed from the scope. Confirm the sample is adequate and repeat as needed. Lesions should be biopsied multiple times to minimize sampling error.Barrett's esophagus is typically biopsied according to the Seattle protocol with 4-quadrant biopsies taken at 1-2 cm intervals. Specimens are sent in separate containers based on the level biopsied. Bleeding is usually minimal but may require topical or injected epinephrine for control.
Postoperative Care
A chest x-ray should be obtained in the recovery room if there is any suspicion of perforation. This should be followed up with a water-soluble contrast swallow study if the CXR is concerning (i.e. presence of a pneumothorax or widened mediastinum). After routine EGDs, patients are typically discharged the same day. Pain medication is rarely required. If any interventions were carried out (i.e. dilation, extensive biopsies, ablative therapies), patients are often directed to take clear liquids the evening of the exam to allow edema to resolve and then may resume their preoperative diet the following day. Follow-up is variable depending on the indication for the procedure and whether any interventions were performed.