Transnasal Esophagoscopy

Comparison With Conventional Endoscopy

The main physical difference between a transnasal esophagoscope and a flexible endoscope used in conventional endoscopy (CE) is size. The diameter of a transnasal esophagoscope ranges between 3.1 and 5.3 mm, depending upon the model, whereas flexible endoscopes used in conventional endoscopy are 10 to 12 mm. Despite its smaller caliber, a transnasal esophagoscope still provides a working channel as well as suction, irrigation, and air insufflation. Currently, three transnasal esophagoscopes are available: (1) the EE-1580-K Color Video Esophagoscope from KayPentax (Montvale, NJ) has a tube diameter of 5.1 mm and a working channel diameter of 2 mm; (2) the PEF-V Video Esophagoscope from Gyrus ACMI/Olympus (Southborough, MA) has a tube diameter of 5.3 mm and a 2-mm working channel; and (3) the ultrathin TNE-5000 Flexible Digital Video Esophagoscope from Vision Sciences (Orangeburg, NY) has a diameter of 3.1 mm; it lacks a working channel, but can be used with the disposable EndoSheath technology to add this function. The larger-diameter endoscopes used in CE typically provide a larger working port or multiple working ports and can provide four-way mobility of the distal end rather than only two-way mobility. The larger size precludes transnasal insertion, which typically translates into the need for sedation during the procedure.

An obvious question in determining the feasibility and applicability of TNE is whether its diagnostic accuracy compares favorably with CE, given the smaller diameter of the endoscope used for TNE. Dean and associates reported a high degree of correlation between the endoscopic findings (sensitivity, 89%; specificity, 97%) of TNE and CE. Other studies reported similar findings. Crossover studies that evaluated endoscopic findings and the histologic diagnostic capability of both TNE and CE in Barrett esophagus were done by Shariff and colleagues in 2012 and Jobe and colleagues in 2006 and found excellent correlation between the two modalities. Studies that evaluated histologic diagnosis reported that the size of the biopsy specimen is noticeably smaller with TNE in comparison with CE, but a high degree of congruence was still present. Specifically, Walter and colleagues evaluated 1035 endoscopic biopsy specimens from 300 endoscopic procedures with 109 procedures performed via awake small-caliber endoscopy and found no significant difference in the rate of definitive histologic diagnosis between small-caliber endoscopic biopsies and those obtained with CE. Similarly, in patients with known Barrett metaplasia, Saeian and colleagues found that the correlation between biopsy specimens obtained with CE and TNE was 97%. In addition, a recent study by Friedlander and colleagues compared esophageal biopsy samples using a standard 2.8-mm biopsy forceps of the conventional esophagoscope with either 1.2-mm or 2-mm biopsy forceps specimens that were collected during TNE in pediatric patients to rule out eosinophilic esophagitis. They found that there was no significant difference when comparing the total epithelial surface lamina propria in specimens.

Moreover, when the TNE was compared with esophageal capsule esophagoscopy in screening for Barrett esophagitis, it was found to be higher in sensitivity and lower in cost than esophageal capsule esophagoscopy.

Given equivalent efficacy, the question of patient tolerance arises. Numerous studies document acceptable patient tolerance of the awake procedure, and the vast majority state that patients prefer the awake transnasal procedure to other methods. When compared with unsedated small-caliber endoscopy via a transoral route, patients report less gagging and nausea with TNE. When directly compared with sedated CE, 59% to 91% of patients preferred TNE. In two recent studies, 88% and 93% of patients who underwent TNE would choose to undergo the awake procedure again if another endoscopic examination was necessary and they were given a choice between CE and TNE. The tolerance of TNE in the pediatric age group has also been evaluated in the literature. Friedlander and colleagues reported that they performed unsedated TNE with biopsies in pediatric subjects to rule out eosinophilic esophagitis (with a 2.8-mm endoscope and 1.2-mm flexible forceps, or a 4-mm endoscope with 2-mm flexible forceps) (Olympus America, Center Valley, Pa). All children had previous esophagogastroduodenoscopy (EGD) under general anesthesia with esophageal biopsy by a standard endoscope. They found that 100% of parents and 76.2% of children would undergo the TNE again. TNE was preferred over the standard EGD by 85.7% of parents and 52.4% of children.

Performing TNE in the office without sedation is safer, more convenient for the patient, and more cost-effective. Indirect costs associated with sedated CE include loss of work time and the need for an additional visit and a separate driver, whereas office-based TNE can often be performed at the same time as the initial office appointment. Furthermore, very little postprocedure recovery time is needed, and the patient is usually able to resume normal activity shortly after the procedure. These convenience factors can be directly attributed to avoidance of sedation. In support of this, Gorelick and colleagues evaluated the time and resource utilization associated with sedation by comparing sedated CE and awake TNE and found that TNE was associated with a shorter procedure time, less time spent in the procedure room, reduced recovery room time, and lower procedure-associated costs. Avoidance of sedation is not only more convenient and cost-effective, but it is safer for patients undergoing endoscopic procedures. Intravenous sedation has been reported to be responsible for over 50% of adverse events associated with CE, such as aspiration, hypoventilation, vasovagal episodes, and airway obstruction.

Several studies have evaluated the physiologic impact of transoral and transnasal endoscopy. In general, TNE is associated with less fluctuation of physiologic parameters—such as blood pressure, heart rate, and oxygen saturation—than transoral endoscopy. Furthermore, one study found fluctuations in heart rate and blood pressure to be more profound in hypertensive patients older than 65 years undergoing transoral endoscopy in comparison to TNE.

Finally, in head and neck cancer patients, reports showed that after surgery or radiation therapy up to 21% of these patients develop physical barriers, such as strictures, which prevent successful intubation with a conventional esophagoscope. On the other hand, a recent study by Wang and colleagues evaluated the TNE's efficacy in overcoming these obstacles. They report a completion rate of 96.7% in performing screening with TNE, which could indicate a superiority of TNE over conventional esophagoscope in these patients.

Indications and Clinical Applications

In 2007, the American Broncho-Esophagological Association (ABEA) published a position statement on TNE that listed indications for the procedure. Indications are divided into three categories: esophageal, extraesophageal, and procedure related. Esophageal indications for TNE include dysphagia, esophageal symptoms that persist despite antireflux therapy, screening for Barrett esophageal metaplasia, visualization and biopsy of esophageal radiologic abnormalities, and long-standing (5+ years) gastroesophageal reflux disease. Extraesophageal indications for TNE include chronic cough, panendoscopy and biopsy for head and neck cancer, moderate to severe laryngopharyngeal reflux, and globus pharyngeus.

In patients undergoing TNE, positive findings were present in 50% of patients who met the above criteria in a tertiary care otolaryngology practice. A multi-institutional study was recently published that evaluated the role of TNE in changing the management of patients. This study reported that TNE findings resulted in changes in management in 51% of patients, and that male gender and elevated body mass index were significantly predictive of a positive finding in TNE that resulted in changes in management. These facts emphasize the potential that TNE possesses for the purposes of screening. Specific situations in which TNE is useful in a screening or monitoring capacity, other than what is included in the 2007 ABEA position statement, include routine screening of head and neck cancer patients for coexistent esophageal pathology, routine esophageal screening for patients with a history of caustic ingestion, and monitoring of esophageal varices. TNE has also been advocated in morbidly obese patients for preoperative evaluation prior to bariatric surgery, given the high likelihood of cardiopulmonary complications with sedation in this patient population. An additional use of TNE in head and neck cancer patients is endoscopic monitoring of the viability of free-flap reconstructions of the pharynx and larynx in the immediate postoperative period.

In regard to esophageal screening in head and neck cancer patients, Farwell and colleagues found that routine esophageal screening in this population had a high likelihood of significant findings such as esophagitis (63%) and stricture (23%), and that only 13% of those screened had a normal esophageal examination. Additionally, Su and colleagues recently examined the records of more than 3000 head and neck cancer patients. Patients were divided into two groups, one that had routine esophageal screening with TNE following initial diagnosis and one that did not have routine screening. A second primary esophageal carcinoma was diagnosed in 115 patients, and those discovered with routine screening were diagnosed at an earlier stage.

TNE has also been used extensively to assist in office-based procedures. For example, TNE has been found to provide diagnostic information that is equivalent to traditional panendoscopy for initial evaluation and biopsy of suspected head and neck cancer. Guidewires can be passed through the working channel to allow both esophageal and airway balloon dilation procedures to be performed in the office. TNE has also been used to place percutaneous gastrostomy tubes without sedation. Laser fibers can be passed through the working channel to ablate laryngotracheal lesions such as papillomas in the office setting. Tracheoesophageal puncture (TEP) for voice rehabilitation after laryngectomy can also be performed using TNE in awake patients. Placement of nasogastric feeding tubes with TNE guidance, particularly in patients with esophageal or head and neck malignancy, has been reported. TNE can be used for Botox injection in the lower esophageal sphincter through the working channel using the endoscopic flexible injection needle in patients with achalasia. TNE can also be implemented as a diagnostic tool to rule out esophageal foreign body in cases of inconclusive lateral neck X-ray, using the flexible forceps through the working channel for esophageal foreign body removal if needed. Another technique for esophageal foreign body removal is by air insufflation through TNE and passing the foreign body down to the stomach. However, this technique must be avoided in cases of sharp foreign bodies.