What Is Laryngotracheal Stenosis (LTS)?

What Is Laryngotracheal Stenosis (LTS)?/Laryngotracheal stenosis (LTS) is a narrowing of the upper airway between the larynx and the trachea with potentially devastating consequences, including respiratory failure, cardiopulmonary arrest, and death. The upper airway is comprised of the larynx, glottis, subglottic region, and trachea. The trachea is a cylindrical-shaped tube with an anterior cartilaginous wall formed by c-shaped rings and a posterior membranous wall. The trachea branches off into the right and left mainstem bronchi at the carina, which is at the level of the fourth thoracic vertebra (T4).

Laryngeal stenosis may occur as a result of trauma, related to endotracheal intubation or due to a neoplasm, autoimmune, or infectious process. It could be asymptomatic or lead to symptoms of upper airway obstruction.

Laryngeal narrowing from any cause calls for a multidisciplinary approach to management, including, but not limited to, pulmonologists, intensivists, otolaryngologists, and gastroenterologists as well as speech and language pathologists, and cardiothoracic surgeons. The determination of the etiology of the laryngotracheal stenosis is critical as it can drive the management and provide prognostic information to the patient.

Laryngotracheal stenosis is a disease that is characterised by mucosal inflammations and bounded fibrosis resulting blockage of the upper airway and life treating conditions. Cricoid is the narrowest portion of the larynx. The first tracheal ring is partially anchored to the lower limit of the cricoid cartilage and, sometimes, can be attached to it [rx]. Small changes of the diameter of the laryngotracheal stem and length of the narrowed segment create important variation in airflow that results in immediately progressive dyspnea requiring urgent interventions [rx]. Symptoms occurred when airway change of 30%, and distress of change of 80%. This condition affects patients their ability to; breathe, modification of voice or swallowing problems [rx].

Types of Laryngotracheal Stenosis

• Idiopathic subglottis stenosis – is defined as laryngotracheal stenosis of unknown origin. Diagnose is made as exclusion and lack of history of traumatic intubation, tracheostomy and negative serologic autoimmune markers. It is a rare, fibroinflammatory process which leads to narrowing the airway of the subglottis, first and the second tracheal ring. When the patient is evaluated by the laryngologist, the scar is mature, circumferential, laryngotracheal stenosis. Mostly affected by woman, probably because of the anatomic predisposition of smaller female subglottis, frequent coughing causing mechanical trauma, subtle vascular disease. It a slowly progressive condition, mild symptoms present in mouths [rx], [rx], [rx].
• Autoimmune laryngotracheal stenosis – It’s not an isolated phenomenon; it’s a present of other organ system involvement. It is known as Wegener granulomatosis, relapsing polychondritis, sarcoidosis. Wegener granulomatosis refers to pulmonary disease. Necrotising vasculitis, cANCA positive and renal disease. Autoimmune laryngotracheal stenosis can have two stages. The first stage is inflammatory is distinguished with erythematic, oedema of the epithelium and granulation tissue. The second stage is mature scar marked as rigid white scar with cicatricle line of fibrosis. If the autoimmune disease is already diagnosed, that the appearance of laryngotracheal stenosis is as a result of inflammatory exacerbation in the larynx. The follow-up course and treatment depend on whether the pre-diagnosed autoimmune disease has been diagnosed or not [rx], [rx], [rx].
• Congenital subglottic stenosis – defined as the diameter of the cricoid of less than 3.5 mm. Congenital subglottic stenosis is the third most common congenital anomaly of the larynx, which accounts for 15% of all cases. Etiopathogenesis: as a defect in the formation of cone elastics and cricoid cartilage, creating an elliptical cricoid, flaccid cricoid, or excessively submucosal cough. Congenital subglottic stenosis can be classified into two types: Membranous congenital subglottic stenosis (granulation tissue, fibrous connective tissue, hyperplastic submucosal glands.) This type is the most common and mild form of congenital subglottic stenosis. The cartilaginous congenital subglottic stenosis results from abnormal cricoid cartilage.

This condition is the most common laryngeal anomaly that requires tracheotomy in infants. Male children are affected twice as often as females [rx], [rx], [rx].

Pathophysiology

The most narrow part of the airway is at the subglottic space at the level of the cricoid cartilage, which extends from the inferior part of the vocal cords to the lower part of the cricoid cartilage.[rx] This area is only a few centimeters in length but can be commonly injured during endotracheal intubation, as the endotracheal tube makes contact with the posterior aspect of the subglottic space during intubation. Prolonged intubation can also cause laryngotracheal stenosis when the cuff pressure exceeds the mucosal capillary perfusion pressure (approximately 35 mmHg), which can lead to ischemia, ulceration of the posterior mucosa, and subsequent fibrotic strictures.[rx] In terms of patients with underlying autoimmune diseases, granulomatosis with polyangiitis (formerly known as Wegener granulomatosis) is the most commonly associated with laryngotracheal stenosis, as seen by the necrotizing granulomatous inflammation that is seen in the upper airways with vasculitis perpetuating fibrotic changes and stenosis.[rx]

Causes of Laryngotracheal Stenosis

Several etiologies have links to the development of laryngotracheal stenosis (LTS).[rx]

• Recognized causes of laryngeal stenosis include: iatrogenic (ex. complication of endotracheal intubation), autoimmune, infectious, neoplastic, traumatic, and idiopathic.
• Autoimmune diseases such as systemic lupus erythematosus, rheumatoid arthritis, vasculitis, sarcoidosis, and scleroderma, among others, can cause laryngotracheal stenosis.
• Infectious causes include bacterial tracheitis, viral papillomatosis, and tuberculosis.
• Neoplasm at the level of the larynx or trachea can also cause narrowing of the airway, with squamous cell carcinoma and adenoma being the most common malignancies in this setting.[rx]
• Direct injury to the trachea by trauma, inhalation burns, or radiation are a few causes of traumatic laryngotracheal stenosis.[rx]
• Acute laryngeal injury has been described as a potential component of post-intensive care syndrome.[rx]  Common post-intubation complications include transient dysphonia, dysphagia, and sore throat for patients undergoing surgery.
• However, these complications present more markedly in critically ill patients. Endotracheal tubes (ETT) can lead to laryngeal injury by direct injury of ETT to the posterior glottis mucosa, which may eventually progress to fibrosis.
• At the level of the larynx (glottis)
  • Bilateral vocal fold paralysis
  • Blunt/sharp laryngeal trauma
  • Foreign body inhalation
  • Sarcoidosis
  • Amyloidosis^[13]
  • Bilateral vocal fold mobility impairment
    • Crico-arytenoid joint fixation
      • Rheumatoid arthritis
      • Intubation-related joint fixation
    • Inter-arytenoid scarring
      • Intubation-related
  • Infections (e.g. Diphtheria, epiglottitis)
  • Respiratory papillomatosis^[14][15]
  • Large ball-valving vocal polyps
  • Congenital laryngeal stenosis
    • Laryngeal atresia
    • Congenital laryngeal webs

• At the level of subglottis/trachea
  • Intubation/tracheostomy-related (most common cause)^[16][17]
  • Granulomatosis with polyangiitis^[18]
  • Idiopathic Progressive Subglottic Stenosis
  • Amyloidosis
  • Tracheopathia osteoplastica
  • Tracheomalacia
    • Expiratory Dynamic Airway Collapse (EDAC)
    • Tracheobronchomalacia
      • Relapsing polychondritis^[19][20]
      • Tracheal ring damage due to COPD
      • Tracheal ring weakness
  • Benign tumors (e.g. Carcinoid)
  • Tracheal trauma / rupture^[21]
  • Congenital subglottic/tracheal anomalies
    • Complete tracheal rings
    • Congenital subglottic/tracheal webs
    • Subglottic haemangioma
    • Subglottic / tracheal cysts^[6]
• At the level of carina or main bronchi
  • Granulomatosis with polyangiitis
  • Foreign body inhalation
  • Tuberculosis
  • Following Photodynamic Therapy

Symptoms of Laryngotracheal Stenosis

There are many, but common symptoms include

• Breathing noises that may change with position and improve during sleep
• Breathing problems that get worse with coughing, crying, feeding, or upper respiratory infections (such as cold)
• High-pitched breathing
• Rattling or noisy breaths
• High-pitched breathing
• Rattling or noisy breathing (stridor)
• Frequent infections in the airway, such as bronchitis or pneumonia (because your child can’t cough effectively or otherwise clear their lungs)
• Frequent noisy cough
• Exercise intolerance
• Prolonged respiratory infections
• Choking during feeding
• A halt in breathing, particularly when crying or during strenuous activity
• Blue spells (child appears blue because they aren’t getting enough oxygen)

Diagnosis of Laryngotracheal Stenosis

History and Physical

Evaluating a patient with suspected laryngotracheal stenosis includes a detailed history and physical examination. History should include any previous endotracheal intubations and their duration, history of infection, autoimmune disease, vasculitis, trauma, surgery, as well as current symptoms. The most common symptoms of LTS from any etiology include dyspnea, stridor, hoarseness, and cough. In the acute emergent setting, a physician may not have enough time to obtain such detailed information, in which case the physical examination becomes crucial. One must be able to identify inspiratory stridor, which is most common in the neck associated with cough and dyspnea. If the patient has extrathoracic stenosis, they may present with hoarseness, inspiratory wheezing, stridor, and nonproductive cough. Intrathoracic stenosis is evident with difficulty in expiration and laying in the recumbent position. There may be decreased ability in clearing secretions, as well as wheezing mimicking asthma without response to bronchodilators.[rx] Localization of the stenosis is difficult on clinical grounds alone.

Evaluation

Laryngotracheal stenosis can be evaluated by laryngoscopy or bronchoscopy. The clinician may obtain computed tomography (CT) scan of the neck in severe cases in which the obstruction does not allow for direct laryngoscopy or patients who have a traumatic injury to the trachea and in planning for surgical treatment.[rx] Performing spirometry on these patients helps establish a baseline and monitor their status over time.[rx]

There are three classification systems based on anatomic characteristics that are derived from intraoperative findings. The Cotton-Myer classification is based on percent stenosis

• (I = < 50% obstruction;
• II = 51% to 70% obstruction;
• III = 71% to 99% obstruction;
• IV = Complete obstruction).

The Lano classification is based on subsite involvement

• (I = one subsite involvement;
• II = two subsite involvement;
• III = three subsite involvement, with the subsite meaning the glottis, subglottis, and trachea).

The McCaffrey classification is based on the length of stenosis

• (I = subglottis or trachea < 1 cm;
• II = subglottis > 1cm;
• III = subglottis and trachea >1 cm;  IV = any lesion involving glottis).

The percent stenosis is important in regards to prognosis, individualized treatment planning, and risk stratification of tracheostomy dependence. Patients with grade III and IV stenosis in the Cotton-Myer classification were found to be tracheostomy dependent compared to patients with grade I and II. Per the Lano classification, larger subsite involvement was associated with a higher risk of tracheostomy dependence, as well as higher stages in the McCaffrey classification. In adult LTS, the Lano and McCaffrey classifications are more precise than the Cotton-Myer scale.[rx]

Treatment of Laryngotracheal Stenosis

There are 3 types of treatment categorised: 1) endoscopic dilatation of the tracheal stenosis; 2) endoscopic resection of the stenosis (medical therapy after surgery); and 3) open surgery resection end to end anastomosis.

The management of laryngotracheal stenosis is complex, as it may entail multiple procedures with the possibility of restenosis in certain cases. Treatment goals are to maintain airway patency, reduce the number of procedures required, and decannulation in patients with tracheostomy. Unfortunately, there is no standard guideline for the approach and management of LTS as of yet. Most of the treatment modalities have been described from various studies from the medical literature across different specialties.

Treatment options for LTS include endoscopic dilatation, surgery, stent placement, laser therapy, or immunosuppression to restore airway patency, depending on the underlying etiology as well as degree and complexity of stenosis.[rx]

Bronchoscopic Approach

Bronchoscopy may be used for mechanical dilation, laser therapy, and stenting to treat laryngotracheal stenosis. These treatment modalities may have limited use in subglottic stenosis due to anatomical challenges. Dilation or laser treatments are options for strictures or granulomas; however, they are at risk of recurrence. Stent placement can migrate and cause a larger airway injury. A laser is typically not used for subglottic stenosis due to the risk of damaging the cricoid cartilage, which is where the laryngeal nerves pass and have a role in vocal cord function. Several studies have shown that laser and stenting reach less than 20% success rates.[rx] Bronchoscopic therapy has been used in cases where the patient is not a surgical candidate to palliate symptoms.

Endoscopic Mechanical Dilation

Endoscopically-guided dilation is performed using several devices, including gum-tipped bougies, endotracheal tubes, or balloon catheters. It could be performed in the outpatient setting for a selected group of patients. This route has more favorable outcomes in regards to voice preservation compared with patients who have stenosis less than 2 cm from the vocal folds, or those who have stenosis in several levels. Endoscopic dilation should be the first-line treatment for simple stenosis, whereas more complex stenoses require an interprofessional approach and possible surgical evaluation. The average patient may be able to go for approximately one year without requiring subsequent dilations.[rx]

Tracheal Stenting

Tracheal stenting is a palliative option for patients with advanced and unresectable cancer-causing airway obstruction. As stated above, stenting is a challenging and risky approach that requires a risk-benefit conversation with the patient. Higher performance status before surgery correlates with better patient outcomes.

A Japanese study by Matsuo et al. aimed to clarify indications for stent placement, which include:

• 1) severe central airway obstruction with dyspnea and flow limitation on a flow-volume curve,
• 2) prognosis will be prolonged by stent placement, and
• 3) peripheral airways and lungs are intact.[rx]

Transoral exposure of the tracheal scar

IT is using rigid tracheobronchoscopy is necessary for balloon dilatation or controlled radial expansion device. Airway balloons are passed through the rigid endoscope, expanding balloon is placed in the middle of the stricture. As the balloon expands, the energy is transmitted of the area of least résistance. The balloon is inflated in enlargement with periodical collapsing to observe progress. Periods of appearing for about 4minuts occur between balloon dilatation intervals. Desideration may occur. Patient with fibro-inflammatory stenosis required fewer procedures rather than mature stenosis.

Preoperative Assessment

Several preoperative assessments may help with prognostication and choosing a suitable treatment modality. The patient should be screened for methicillin-resistant staphylococcus aureus (MRSA) colonization at least two to three weeks prior to possible surgery as infection may lead to more postoperative complications. If patients test positive for MRSA, they should be treated prophylactically with a three-day course of double strength trimethoprim-sulfamethoxazole orally and mupirocin intranasally, as well as fourteen days of intravenous vancomycin postoperatively until all drains have been removed. Before pursuing further treatment, patients should also undergo a swallowing evaluation by way of fiberoptic endoscopic evaluation of swallowing (FEES) or modified barium swallow study (MBS) to determine the ideal mode of delivery postoperative nutrition. FEES also assesses mobility of the vocal folds and extent of the stricture.[rx]

Open Surgery

Open surgery is offered in patients with Myer-Cotton grade III or IV, loss of cartilage, or stenosis longer than 1 cm. Open surgery is an option in cases with hard tissue and scar tissue greater than 1cm in length. Surgical cases have had more success rates, whereas endoscopic procedures end up requiring more repeat interventions.

Open surgery may divide into

• 1) laryngotracheal resection with reanastomosis or
• 2) laryngotracheoplasty using native and tissue grafting. [rx]

Laryngotracheal resection with reanastomosis

A systematic review by Lewis et al. found that laryngotracheal resection with anastomosis was associated with a decreased need for additional surgeries and an increased rate of decannulation when compared to endoscopic procedures. They also found that patients with idiopathic stenosis required less additional surgery compared to patients with laryngotracheal stenosis due to trauma or intubation.[rx]

Laryngotracheoplasty

Laryngotracheoplasty encompasses different surgical techniques that involve a single-stage or multistage approach to use different types of luminal grafts or tracheal stenting.[rx] Outcomes are typically favorable, with a high percentage of decannulation rates. They also have low postoperative complications, which include granulation tissue and glottic edema. They may be treated with a short course of dexamethasone for 24 to 48 hours,  as well as diuresis and elevating head of the bed.[rx][rx]

Montgomery T-Tube

The Montgomery T-tube is placed through the trachea’s anterior wall distal to the anastomosis. It provides a stable airway for prolonged periods (at least six months) until the consideration of decannulation, or permanently in inoperable cases.[rx][rx][rx]

Adjunctive Treatments

Several adjunctive treatment options are currently used for the treatment of LTS. A review of the literature suggests the use of adjunctive treatments such as mitomycin C, steroids, and proton pump inhibitors.

Mitomycin C

Mitomycin C is a chemotherapeutic agent that is applied topically for four minutes after making an incision. It works as an alkylating agent that inhibits cell division, protein synthesis, and fibroblast proliferation, ultimately decreasing the formation of scar tissue. It has been reported that this may be a therapeutic option for thinner stenoses; however, restenosis may occur at similar rates at five years with or without reapplication.[18]

Steroids

For patients undergoing dilation, corticosteroids injected locally or systemically in oral form have favorable evidence in current data, with greater success noted in stenoses that are greater than 1 cm thick.[rx][rx]

Stents – are placed in stenosis greater than 70% and no longer than 5 mm for 4-6 weeks to aid healing. Disadvantages are granulation tissue formation of the proximal and distal end of the T-tube and stent.

An open approach is indicated after the failure of the endoscopic approach when the degree of stenosis is severe, or factors are unfavourable for this approach. Choosing the specific technique is based on the length of the resection, the need for cartilage tissue and the need for mucosal coverage, placement of a stent is necessary for some procedures. In advanced stages of the laryngotracheal stenosis, especially in the matriculated stenosis, the treatment of choice is resection and end to end anastomosis.

Pediatric laryngotracheal stenosis – is researched all rib graft if possible, tracheal or cricotracheal resection and an end to end anastomosis. On the other hand, adult laryngotracheal stenosis treatment options are tracheostomy, tracheal resection or cricotracheal resection associated with great morbidity and mortality. Anterior and/or posterior cricoid split with stenting and graft is rarely used in our country.

Tracheal resection – is preserved for a patient with a long segment complete or complete collapse of the cartilaginous tracheal support. Cricotracheal resection is a procedure that requires the removal of subglottic scar tissue, with anastomosis of a healthy trachea with the healthy larynx. The procedure is consisting of elevation of perichondrium from cricoid cartilage anteriorly to avoid recurrent nerve injury, removal of subglottic stenotic tissue, removing soft tissue in posterior cricoids. Laryngofissure may be made to increase the lumen in the laryngeal box, a tracheal submucosal flap in the treatment of posterior subglottic stenosis, full reconstruction with end-end anastomosis.

Over resection of the anterior tracheal rings during tracheostomy, at decannulation can cause scarring and contracture of the stoma site. It looks like a lambda shaped stenotic deformity tie the lateral regions fragment resulting wound contracture. Endoscopic is more recommended in this condition rather than open tracheal resection and anastomosis.

Patients with grade 3 and 27% of respondents are on 30% of them subject to laryngotracheal resection with excellent outcome, the remaining patients due to their accompanying comorbidities are with a tracheostomal aperture or the remaining 70%.

Patients with grade 4 and 19% of respondents use 57% of them subject to laryngotracheal resection with excellent outcome, the remaining patients due to their accompanying comorbidities with a tracheostomal aperture or the remaining 43%.

Mature scar distinguishes –  itself with a positive treatment of 70% about its total number.

Subglottic/tracheal stenosis – that do not involve glottis or grades 3 at McCaffer classification is 12 patients. Of them, 6 patient laryngotracheal resection and anastomosis were performed or 50% leading to decannulation in all of them. Some recommend prolonged postoperative neck flexion with the longue or chin-to-breast sewing in the end-to-end anastomosis.

In the postoperative treatment

• Antibiotics are given for 1-3 weeks, depending on the degree of recovery and general health of the laryngotracheal mucous membrane. According to the surgical intervention administration of antibiotic is needed. Authors advocate the elimination of antibiotics when a stent is used. Intensive anti-reflux therapy is needed Injecting steroid sprays (not nasal sprays) are sometimes useful for reducing the granulation tissue of the surgical wound.

After 6 weeks, control is taken to determine the condition of treatment and the need for further procedure. Whenever is required or not, tracheostomy was implemented.

Some authors want immediate extubation after reparation; some support 1-2 days of postoperative intubation in intensive care units; and some require extubation in the operating room, rather than in intensive care units.

Differential Diagnosis

Some differential diagnoses that must be considered in the evaluation of laryngotracheal stenosis include the following:[rx]

• Angioedema
• Asthma
• Epiglottitis
• Esophageal tumor
• Foreign body aspiration
• Gastroesophageal reflux disease
• Mediastinal mass
• Retrosternal goiter
• Subglottic web
• Tracheomalacia
• Vocal cord dysfunction

Complications

Acute LTS (for example, in post-extubation LTS) may result in respiratory arrest if not correctly identified in a timely manner. In idiopathic LTS, complications include changes in voice, tracheostomy dependence without the ability to decannulate, and the requirement for multiple procedures.

Tracheostomy decannulation is a target goal of open surgery. Approximately 63 to 95% of patients who undergo open surgery are successfully decannulated. However, patients with grade III or IV stenosis (Myer-Cotton scale), diabetes, gastroesophageal reflux disease, diabetes, and/or body mass index (BMI) greater than 30 may have higher tracheostomy dependence rates.

Additionally, open surgery may be complicated by dysphagia due to injury to the recurrent laryngeal nerves or the use of a stent to maintain airway patency.[rx]

A prospective study by Bibas et al. in the Journal of Thoracic Disease found that quality of life in patients with tracheal stenosis from a benign origin (such as endotracheal intubation, not amenable for surgical treatment) is severely impaired.[rx] Health-related quality of life entails the physical and mental welfare of the patient and their family. This study included patients with Montgomery T-tubes, endotracheal silicone stents or tracheostomy, and the ability to fill out a questionnaire. They excluded patients with chronic comorbidities, such as chronic obstructive pulmonary disease, advanced heart failure, and renal failure.