Management of Tracheal Stenosis

Introduction

Pediatric tracheal stenosis is the clinical presentation of a diverse and complex spectrum of disease processes. Etiologies range from iatrogenic injury, trauma, infection, congenital malformations, neoplasms, gastroesophageal reflux disease (GERD), autoimmune processes, and granulomatous diseases. Classification is necessary in order to better define the stenosis and the spectrum of causes and to determine appropriate management. Stenosis can be classified as acquired versus congenital, intraluminal versus cartilaginous framework versus extrinsic compression, and short versus long segment.

The pathogenesis of acquired stenosis includes injury to the tracheal lining or its cartilaginous framework, resulting in scarring or loss of support. The laryngotracheal cartilaginous framework depends on the perichondrium for its blood supply. Ischemic cartilage can lose its mechanical integrity and collapse, thereby leading to a functional stenosis. Furthermore, exposed cartilage deprived of its blood supply can necrose rapidly and act as a foreign body; the ensuing inflammatory reaction causes further tissue destruction and scarring. This injury can result in a variety of stenoses ranging in severity from thin tracheal webs to severe long-segment stenosis.

Congenital tracheal stenosis (CTS) results from tracheomalacia, external vascular compression or rings, tracheal hypoplasia, funnel stenosis, segmental stenosis, complete tracheal rings, and tracheal agenesis. Cantrell and Guild first described intrinsic congenital tracheal stenoses and classified them into three morphologic types: (1) generalized hypoplasia, (2) funnel stenosis, and (3) segmental stenosis ( Fig. 199.1 ).

Fig. 199.1, Cantrell and Guild congenital tracheal stenosis classification: A, generalized hypoplasia, B, funnel stenosis, C, segmental stenosis.

An in-depth discussion of the pathogenesis of tracheal stenosis is beyond the scope of this chapter. With regard to CTS, the definitive pathogenesis is unknown. Additionally, several theories of embryologic tracheal development are still being debated.

Surgical techniques available for management of tracheal stenosis are endoscopic dilation, endoscopic stent placement, costochondral cartilage tracheoplasty, pericardial patch tracheoplasty, tracheal autograft tracheoplasty, tracheal resection with reanastomosis, and slide tracheoplasty. There have also been a few reports of tracheal transplantation for extreme cases. Many forms of acquired stenosis are amenable to endoscopic management. Although small-segment acquired tracheal stenosis may be amenable to balloon dilation, this technique is not recommended for the treatment of complete tracheal rings. Slide tracheoplasty and tracheal resection with reanastomosis have evolved as the current recommended primary open techniques for pediatric tracheal stenosis and owing to their wide acceptance and application; these techniques are discussed in this chapter.

Key Operative Learning Points

1.
It is essential in management decision making to classify the stenosis with the etiology, degree of narrowing, length of stenosis, and whether it is intraluminal or involves deformed cartilage.
2.
Slide tracheoplasty is the surgical treatment of choice for long-segment stenosis and complete tracheal rings; it can be used for a variety of lengths of stenosis.
3.
For mild stenosis of the trachea, observation can be a safe and reasonable option.
4.
Some 50% to 70% of congenital tracheal stenoses have associated cardiovascular malformations; preoperative cardiac evaluation is recommended.
5.
Previous open airway surgery or chest surgery has produced a scarred or shortened trachea, which can make resection with anastomosis difficult or impossible to perform.

Preoperative Period

History

1.
History of present illness
- a.
  What symptoms are present? The degree of dysfunction and therefore the clinical manifestations of tracheal stenosis vary widely. Patients with tracheal stenosis may complain of shortness of breath, dyspnea on exertion, expiratory or biphasic stridor, hoarseness, dysphagia, aspiration, difficulty clearing secretions, recurrent pneumonia, or any combination of these symptoms and signs. Children often have a history of recurrent croup or cardiopulmonary problems. Symptom severity likely correlates with degree of stenosis.
- b.
  Are symptoms present at rest? Symptoms result from a narrowed airway lumen, which limits the physiologic demands of mucociliary clearance, tidal volumes, and gas exchange. It is generally estimated that the presence of symptoms with activity indicates a 50% stenosis of the tracheal lumen; symptoms at rest occur with a 75% stenosis.
- c.
  What was the age of symptom onset? Neonatal: Typically severe stenosis and critically ill. Cantrell and Guild type 1 occurs more commonly and is often accompanied by significant cardiovascular malformations. There is a 70% to 100% mortality when patients with CTS present in a critically ill state. ² Infancy: Stenosis symptoms present at several months of age, when there is an increase in physical activity and tidal volumes. Childhood/adolescence: Often incidental findings, present with mild symptoms and typically mild stenosis. Exercise-associated symptoms are common.
- d.
  What is the severity of symptoms and quality of life effects?
  - 1)
    Are there frequent emergency department visits? Admissions? Treatments?
  - 2)
    What exacerbates the symptoms? Activity? Infection? Position?
2.
Past medical history
- a.
  Birth history of prematurity or admissions to the neonatal intensive care unit (Neonatal Intensive Care Unit)
- b.
  Recurrent croup
- c.
  Apparent life-threatening events (ALTEs)
- d.
  Other congenital malformations: Stenoses are associated with pulmonary, cardiovascular, and gastrointestinal malformations.
- e.
  Intubations: Multiple factors play a role in the etiology of tracheal stenosis after endotracheal intubation. Time of intubation, size of the tube relative to the airway, pressure and friction by the tube or cuff, repeated intubation, foreign-body reaction to the tube, release of toxic substances used for sterilization, use of a stylet, route of intubation (nasal or orotracheal), nursing care techniques (suctioning, fixation), and anatomic differences between the genders are among many important factors that can be correlated with the development of postintubation stenosis. Because the microcirculation of the tracheal mucosa is impaired at a pressure of 30mm Hg, a low-volume, high-pressure cuff is more likely to cause an ischemic injury than a high-volume, low-pressure cuff. Nonetheless, an overinflated, high-volume cuff can impede the microcirculation and produce the same injury as a low-volume cuff.
- f.
  Infections or autoimmune disorders: Tuberculosis, histoplasmosis, blastomycosis, diphtheria, leprosy, and syphilis are endemic in several parts of the world. Stenosis due to inflammation, chondritis, or necrosis can occur. Diseases such as relapsing polychondritis and Granulomatosis polyangiitis (GPA) can destroy the cartilaginous framework and thereby lead to collapse of the airway. Stenosis occurs in 10% to 20% of patients with Granulomatosis polyangiitis, and the mainstay of treatment remains medical. These causes are important to identify preoperatively because tracheal repair in an active state of disease can exacerbate the disease or predispose to restenosis.
3.
Past surgical history
- a.
  Bronchoscopies
- b.
  Endoscopic airway procedures
- c.
  Open airway reconstruction
- d.
  Tracheostomies
- e.
  Tracheoesophageal fistula (TEF) repair
- f.
  Cardiothoracic surgery
4.
Medications
- a.
  H2 blockers/proton pump inhibitors (PPIs)
- b.
  Steroids
- c.
  Inhaled/nebulized bronchodilators

Physical Examination

1.
General
- a.
  Weight/height/growth curve
2.
Respiratory
- a.
  Tachypnea
- b.
  Expiratory or biphasic stridor
- c.
  Biphasic wheezing
- d.
  Tripod positioning
- e.
  Nasal flaring
- f.
  Intercostal, sternal, or suprasternal retractions
- g.
  Cyanosis
3.
Face and oral cavity: Examination can reveal additional sites of airway obstruction and possibilities of a difficult airway, such as craniofacial abnormalities, trismus, retrognathia, micrognathia, or tonsillar/lingual hypertrophy.
4.
Neck: Scars, length, restriction of mobility, tracheostomy. These findings can indicate prior surgical interventions as well as the feasibility of future procedures.
5.
Fiberoptic laryngoscopy: Evaluate for vocal fold mobility, upper airway sites of obstruction, and glottic lesions.
6.
Laryngoscopy/bronchoscopy: Visualization is crucial in determining laryngomalacia, tracheomalacia, length of stenosis, grade of stenosis, dynamic or static stenosis, thin webs, fresh versus mature stenosis, or complete tracheal rings. It is of utmost importance to avoid trauma to the mucosa of the stenosis during examination, especially with complete tracheal rings. Any worsening edema or scarring may create an unstable airway that can be extraordinarily difficult to manage. Consider passing a scope through the stenotic segment only if it can be passed with minimal contact and no trauma to the surrounding mucosa. Otherwise distal evaluation of the airway during bronchoscopy should be avoided. Fig. 199.2 demonstrates the endoscopic view of complete tracheal rings and complex tracheal stenosis. demonstrates a bronchoscopic examination of complete tracheal rings.

Imaging

Chest radiograph: Plain films can help to evaluate the extent of the lesion, external compression, or pneumonia. In small children, soft tissue radiographs may be sufficient to localize and grade the stenosis with the addition of direct visualization.

Computed tomography (CT)/CT angiography (CTA)/magnetic resonance imaging (MRI): If the patient’s status allows for imaging, CT and MRI can provide excellent evaluations of tracheal lesions as well as possible cardiovascular anomalies. Some 50% to 70% of CT examinations show associated cardiovascular malformations. CT better ascertains the integrity of the cartilaginous framework. Spiral CT with three-dimensional reconstruction enables evaluation of the extent, shape, and site of the stenosis ( Fig. 199.3 ). Although for narrow stenosis it may lack adequate spatial resolution, three-dimensional reconstruction allows for the possibility of “virtual” endoscopy. MRI allows direct imaging in the sagittal and coronal planes, which may be useful in planning treatment. Limitations of MRI are both the long scanning time and artifacts created by cardiac and respiratory movement; however, it can offer better detail of cardiovascular anomalies.

Fig. 199.3, High-resolution CT with 3D airway reconstruction demonstrating tracheal stenosis.

Pulmonary function testing with flow-volume loops: Useful in cases of mild to moderate stenosis with symptoms presenting later in life ( Fig. 199.4 )

Fig. 199.4, Flow-volume loop in a patient with mild tracheal stenosis demonstrating flattening of inspiratory and expiratory phases.

Echocardiography: Obtained to evaluate for a high incidence of cardiovascular anomalies

Esophagogastroduodenoscopy (EGD): If symptoms of reflux, food intolerance, and significant airway edema are present, then a gastrointestinal (GI) evaluation for uncontrolled reflux or eosinophilic esophagitis and its management is warranted. Chronic inflammation from pepsin and acid can contribute to mucosal injuries and exacerbate existing stenosis. Patients with stenosis should be carefully monitored and aggressively treated for gastroesophageal reflux and eosinophilic esophagitis.

Laboratory data: Complete blood count, coagulation studies, and blood chemistry are needed if significant blood loss is expected or if cardiovascular anomalies are being simultaneously repaired with cardiopulmonary bypass (CPB) or extracorporeal membrane oxygenation (ECMO).

Indications

1.
Critical stenosis with or without underlying cardiovascular anomalies
2.
Symptomatic stenosis with significant impairment in quality of life
3.
Neonatal stenosis with anticipated symptoms and future respiratory impairment

Contraindications

1.
Unstable, critically ill patients with multiple comorbidities who are unable to tolerate surgery
2.
Incidental stenosis without symptoms or expected future risk

Preoperative Preparation

1.
Establish an airway management algorithm for the procedure and coordinate the plan with the anesthesiology team.
2.
Determine if CPB or ECMO will be needed for surgical access or for any combined cardiovascular procedures.
3.
Consider screening for methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas , and gram-negative bacterial colonization.

Operative Period

You're Reading a Preview

Become a Clinical Tree membership for Full access and enjoy Unlimited articles

Become membership

If you are a member. Log in here