Discussion

Management of laryngotracheal stenosis is extremely challenging. The desired outcome is to re-establish epithelial continuity and reduce the formation of granulation tissue with ensuing fibrosis. This is accomplished by enabling the wound to heal around a relatively inert object which withstands the contraction process.^{Reference Mandal, Muralidhar, Kumar, Kaul and Ghosh1} Stenting is used when the trachea is malacic or cannot sustain stable patency, or when surgical treatment is not feasible.^{Reference Glikson, Abbass, Carmel, Primov-Fever, Alon and Wolf2}

To our best knowledge, this is the first paper to illustrate the role of a modified nasopharyngeal airway device as a temporary laryngeal stent. The use of a stent was strongly indicated as it addressed our patients’ primary concern for phonatory function. We chose one that suited their financial situation and was readily available. The modified nasopharyngeal airway device was the perfect option to fulfil the patients’ requirement for immediate vocalisation.

Many factors need to be considered during stent selection. Features of the ideal stent include the ability to be inserted and removed easily, fit the specific shape of stenosis, and maintain post-operative airway patency with minimal migration. In addition, it needs to be constructed of inert material to minimise granulation tissue and it needs to be affordable.^{Reference Lee, Kupeli and Mehta3} We believe the nasopharyngeal airway device largely fulfils the above criteria.

The nasopharyngeal airway device is available in various sizes, allowing us to pick one that fits the stenotic segment. The length of the nasopharyngeal airway tube can be trimmed to the desired length. Bourinet et al.^{Reference Bourinet, Raguin, Fortin, Chetrit, Guinde and Laroumagne4} reported that it is crucial to leave at least 1 cm between the upper margin of a stent and the vocal folds, to avoid discomfort and obstructive complications such as laryngeal oedema and granulation tissue formation below the vocal folds. We were meticulous in our measurements so as to ensure that our stent was a precise fit.

The material in contact with the laryngotracheal mucosa is a key aspect that determines tissue changes.^{Reference Saxena, Kaul, Saxena, Agarwal and Chopra5,Reference Saxena, Kaul, Saxena and Chopra6} Several papers have described the use of an endotracheal tube as a temporary stent.^{Reference Yu, Liu, Hsieh and Ko7–Reference Jacobs, Elliott, Haw, Bailey and Herberhold9} However, endotracheal tubes are commonly made of polyvinyl chloride. Polyvinyl chloride, while inert by itself, is combined with plasticisers, stabilisers, antioxidants, lubricants, pigments and other filler material, which may cause irritation to the laryngotracheal mucosa.^{Reference Mandal, Muralidhar, Kumar, Kaul and Ghosh1} Mandal et al.^{Reference Mandal, Muralidhar, Kumar, Kaul and Ghosh1} reported that irreversible changes such as fibrosis were seen after just four weeks. As such, we preferred the nasopharyngeal airway device, which is made of silicon and is similar to the Montgomery T-tube.

Commercially available stents are expensive. Moreover, these stents must be ordered, taking several weeks to arrive. We did not use a finger cot, as we required a hollow stent for vocalisation. For our case series, the modified nasopharyngeal airway device was ideal for avoiding restenosis while addressing our patients’ needs for urgent phonatory function.

Our patients were monitored closely for aspiration symptoms, as we used open stents and placed them just inferior to the vocal folds. Open stents were preferred to closed stents because our patients had a high vocal demand and needed immediate phonatory function. We believe their normal vocal fold sensation and movement played an important role in preventing aspiration.

One complication of stent placement is granulation formation at the ends of the stent.^{Reference Prasanna Kumar, Ravikumar, Senthil, Somu and Nazrin10} Granulation implies the site of future scar development with subsequent stenosis, and their occurrence denotes a propensity towards restenosis.^{Reference Mandal, Muralidhar, Kumar, Kaul and Ghosh1} In order to prevent or minimise granulation, our patients were prescribed systemic antibiotics and inhalational steroids.

Another disadvantage of stenting is stent migration, which can be averted with proper endoscopic stent placement. Anchoring the stent endoscopically typically requires a specialised needle carrier to place the sutures. In reality, many centres do not have this designated needle carrier. It is also a challenge to pass sutures endoscopically from the laryngeal lumen out of the anterior neck skin because of the narrow surgical field of a laryngoscope. Mace et al. described a suture technique whereby the needle is passed through the skin and trachea into the lumen of the stent and angled to exit laterally.^{Reference Mace, Sandhu and Howard11} The needle is then reversed through the same exit and entry points, passing through only subcutaneous tissue.^{Reference Mace, Sandhu and Howard11} This approach was not suitable for our patients owing to the fibrosis caused by their previous laryngeal trauma, and it would be difficult for the needle to pass through the subcutaneous tissue. This method also poses a problem for patients with thick necks, as it may not be possible for the needle to reach the lumen of the stent. We devised a novel technique to address these difficulties.