History

The work of many pioneers has enabled the modern physician to visualize and study the esophagus.¹ Bozzini, in 1806, was the first physician to report the ability to visualize the proximal esophagus.² After studying the performances of sword swallowers, Kussmaul performed the first rigid esophagoscopy in 1868. Advances in equipment continued to be made through the work of physicians such as Von Mikulicz (1881, first electrically lighted esophagoscope), Einhorn (1897, distal illumination in an esophagoscope), and Jackson (advances in endoscopic instruments). Interestingly, Jackson did not use anesthesia, general or local, for esophagoscopy of adults.

While advances in equipment, lighting, and optics were being made in rigid instrumentation, a major advance toward flexible esophagoscopy was made through the work of Hirschowitz and associates,³ who presented the first fiberoptic gastroscope in 1957. Since that time, the examination of the esophagus has been conducted primarily by gastroenterologists with flexible endoscopes and patient sedation. Shaker,⁴ a gastroenterologist, published the first report of unsedated transnasal esophagogastroduodenoscopy (EGD) in 1994. Although initially met with limited interest from gastroenterologists, the appeal of unsedated transnasal esophagoscopy (TNE) grew among the otolaryngology community, particularly after the reports of Herrmann and Recio⁵ and the live demonstration by Aviv and colleagues⁶ in 2001.

Equipment

One of the primary differences between a transnasal esophagoscope and a standard flexible oral esophagoscope is the instrument diameter—3.1 to 5.1 mm versus 10 to 12 mm. Most transnasal endoscopes are able to suction and insufflate air, and contain a working channel. The working channel can be used for passing biopsy forceps or brushes, laser fibers, guidewires for balloon dilators, and the topical application of anesthesia. However, ultrathin transnasal esophagoscopes may lack these capabilities and require an add-on sheath, which may increase the diameter by 1.3 mm. The length of a flexible laryngoscope is 30 to 35 cm, but that of transnasal esophagoscopes is typically at least 60 cm to allow visualization of the entire esophagus, including a retroflexed view of the gastroesophageal junction.

Two main camera systems exist for TNE. The proximal “add-on” camera is familiar to most otolaryngologists who perform endoscopy. Endoscopes utilizing this tool typically lack a working channel and require an add-on sheath. Alternatively, distal videochip technology has emerged, whereby optical impulses are converted to electric signals without the need for optical fibers.⁷ A separate video processor is required for visualization in this system (Fig. 73-1).

Figure 73-1. Video chip transnasal esophagoscope. An add-on camera is not needed with this system.

Tolerance of Unsedated Examination

Historically, examination of the esophagus has been performed with patient sedation. Analyses of the complication patterns during endoscopy reveal that most adverse events are related to sedation. Cardiopulmonary complications account for more than 50% of all reported complications, with the majority being due to aspiration, over-sedation, hypoventilation, vasovagal episodes, and airway obstruction.⁸ A 2007 national survey of endoscopists confirmed that unplanned cardiopulmonary events secondary to conscious sedation constitute the majority of endoscopy complications—67% of complications and 72% of mortalities were cardiopulmonary related.⁹

In addition to the medical risks of sedation, economic factors arise. The increased direct costs of conventional esophagoscopy include a longer procedure time, longer recovery time, and the costs associated with the needed medications, sedation, and recovery teams.¹⁰ Unsedated TNE has been found to be up to two thirds less expensive than conventional esophagoscopy.^11,12 Indirect costs accrued with conventional esophagoscopy include the loss of work time for both the patient and an adult for patient transportation. In contrast, with an unsedated examination, patients are able to resume routine daily activities shortly after completion of the study.

Physiologic studies have verified that unsedated esophagoscopy is a safe procedure. In a prospective study, the changes in systolic and diastolic blood pressures, pulse rate, and rate-pressure product, as well as the drop in arterial oxygen saturation experienced by patients who had conventional transoral EGD, were significantly greater than in those undergoing either transnasal or transoral small endoscopy. Between the two small endoscope groups, these same parameters had a significantly greater change in the transoral group than in the transnasal group at 2 minutes after esophageal intubation.¹³ Additional studies have shown that a significant increase in heart rate and a significant decrease in oxygen saturation occur in those undergoing transoral esophagoscopy but not in those undergoing transnasal esophagoscopy.¹⁴

Although initial patient anxiety is higher before unsedated TNE, numerous studies have demonstrated a very high patient satisfaction rate, usually greater than that for conventional or transoral approaches.^15–18 Crossover studies have shown that in patients who have undergone both sedated and unsedated endoscopy, the unsedated examination was better tolerated.¹⁹ Dumortier and coworkers²⁰ found that 91% of patients who had undergone unsedated TNE who had also previously had a conventional EGD stated that they preferred the TNE examination. TNE was associated with fewer gagging sensations and was rated with higher patient satisfaction than unsedated transoral examinations.^21–23

Accuracy of Examination

Dean and associates²⁴ reported a high degree of correlation between the endoscopic findings (sensitivity 89%, specificity 97%) of TNE examinations and of conventional EGD. Although the biopsy sample size obtained with TNE is generally smaller than that obtained with conventional endoscopy, numerous studies have verified the accuracy of TNE-guided biopsies. In patients with known Barrett’s metaplasia, Saeian and colleagues²⁵ found that the congruence between biopsy samples obtained with conventional endoscopy and those obtained with TNE was 97%. In a crossover study of 121 patients, Jobe and colleagues²⁶ compared the endoscopic findings and the histologic detection of Barrett’s esophagus from biopsy specimens obtained from unsedated TNE and conventional esophagoscopy. A moderate to very good extent of agreement was present for endoscopic findings, such as hiatal hernias and esophagitis, between the two endoscopic modalities. In addition, although the biopsy specimen size was significantly smaller with TNE, there was a moderate extent of agreement in pathologic findings.²⁶

Technique

The most important step in performing TNE is proper nasal anesthesia and decongestion. With the patient in a sitting position, the more patent nasal cavity is sprayed with a mixture of a topical anesthetic and decongestant and then packed with a cotton pledget soaked in the same mixture. A topical anesthetic may be administered to the oropharynx. Too much anesthesia may actually make the TNE procedure more difficult owing to the accumulation of secretions in the hypopharynx that may be aspirated and induce coughing.

The endoscope is lubricated and introduced into the naris. It may be passed either along the floor of the nose—the preferred method—or between the middle and inferior nasal turbinates. As the scope approaches the post-cricoid region, the patient’s head is flexed toward the chest. The patient performs a swallow as the endoscope is gently introduced into the esophagus. Air insufflation and suction are used, as needed, to improve visualization. The scope is advanced only when the lumen is clearly seen.

The endoscope is advanced into the distal esophagus for visualization of the gastroesophageal junction and the squamocolumnar junction (SCJ), also known as the Z-line. The endoscope is advanced more deeply into the stomach and retroflexed to visualize the gastric cardia. The mucosa of the entire esophagus is examined while the instrument is withdrawn. The post-cricoid region is visualized by insufflation of a burst of air as the endoscope is withdrawn from the esophagus (Fig. 73-2).¹⁵

Figure 73-2. Examination technique. The unsedated patient is seated comfortably throughout the entire examination.

Normal Findings

The anatomy of the esophagus viewed through a thin endoscope appears different from that obtained through a rigid esophagoscope or a conventional oral esophagoscope.²⁷ By nature of the smaller size of the scope, TNE does not distort the anatomy of the esophagus, thereby allowing the natural curvatures and external compressions to be easily seen.

Three major curvatures of the esophagus are encountered before the endoscope enters the stomach. At the base of the neck, the esophagus curves to the left with a gentle return to midline at the level of T5. Another left curve is encountered at T7. Finally, an anterior curve occurs in the distal esophagus as it passes through the diaphragm.

Three external compressions are seen during a TNE examination. The first encountered is a pulsatile compression of the left anterolateral wall from the aorta. Approximately 2 cm more distal, the left main bronchus produces an anterior compression. In the distal esophagus, the diaphragm produces a circumferential constriction best visualized by having the patient sniff.

A network of terminal linear vessels can be seen in the distal esophagus that end at the gastric rugae. These vessels do not normally extend below the level of the SCJ. Folds of the gastric rugae form may extend up to 2 cm above the pinch of the diaphragm. Proximal extension of the rugae beyond 2 cm indicates a hiatal hernia. The presence of a hiatal hernia may also be suggested by visualization of a loose diaphragm crus on the retroflexed view.