How To: New Treatment Strategy for Subglottic Stenosis Using the Trachealator

by Leonie G. M. Wijermars, MD, PhD, Carlijn E. L. Hoekstra, MD, PhD, Thao T. T. Nguyen, MD, Markus F. Stevens, MD, PhD, and Frederik G. Dikkers, MD, PhD •

INTRODUCTION

Subglottic stenosis is a severe and, when progressive, life-threatening condition. Throughout the past decennia, numerous surgical approaches for subglottic stenosis have been used, but the optimal procedure is yet to be determined. The surgical approaches are generally categorized as either endoscopic or open surgical repair. The most common endoscopic strategies are dilatation (through rigid or flexible dilatators or balloon dilatation), incision (cold steel or CO2 laser) followed by dilatation, or excision (cold steel or CO2 laser). All these procedures may be combined with additional stenting or (local) medical therapy (JAMA Otolaryngol Head Neck Surg. 2020;146:20-29).

Historically, for subglottic stenosis, we performed dilatation tracheoscopy using the Groningen Dilatation Tracheoscope (Ann Otol Rhinol Laryngol. 2009;118:329-335). During this dilatation tracheoscopy, ventilation of the airway distal to the stenosis is maintained through the tracheoscope. This allows for continuous dilatation of up to 10 consecutive minutes. This longer duration of dilatation is thought to be an advantage compared to the shorter duration of dilatation achieved by balloon dilatation. In conventional balloon dilatation, the airway is blocked, only allowing for intermitted dilatation for approximately 30 to 60 seconds each time and avoiding patient hypoxemia (JAMA Otolaryngol Head Neck Surg. 2017;143:500-505). A recent study in rabbits showed significantly more effect after long compared to short dilatation (Otolaryngol Head Neck Surg. 2020;163:1003-1010).

The main disadvantage of the Groningen Dilatation Tracheoscope is an increased risk of damage to the airway epithelium due to the sheer stress exerted. During balloon dilatation, the airway epithelium only endures the acting radial forces in the balloon, which has a lower risk of causing epithelial damage.

Continuous ventilation is advantageous because it allows prolonged dilation. However, a preference for balloon dilatation is argued due to the lower risk of impairing the airway epithelium.

METHOD

Between October 2020 and June 2021, seven patients with idiopathic subglottic stenosis were operated on in our institution using this new endoscopic strategy. According to the Central Committee on Research involving Human Subjects, this new treatment strategy does not require approval from an ethics committee in the Netherlands; however, all patients gave their informed consent for the procedure.

Patients were brought under general anesthesia by total intravenous anesthesia and monitored muscle relaxation. After pre-oxygenation through mask ventilation, a modified Bouchayer laryngoscope was introduced. Once the clear vision of the glottis and subglottic stenosis was achieved, the supraglottic superimposed high-frequency jet ventilation (SSHFJV) was connected. The SSHFJV uses two jet streams with different frequencies simultaneously to provide adequate oxygenation and decarboxylation. With the fast stream, the SSHFJV fires on a high frequency (usually 600/minute but up to 1,500/minute) to provide oxygenation. On the slow stream, a superimposed low frequency shifts the pressure level at the tip of the laryngoscope (some 10–20 cm H2O) up and down, typically at a frequency of 12–20/min, allowing for CO2 elimination. Oxygenation and CO2 are continuously measured transcutaneously.