Subglottic Stenosis in Children 

Updated: May 20, 2019
Author: John E McClay, MD; Chief Editor: Arlen D Meyers, MD, MBA 

Overview

Practice Essentials

Subglottic stenosis (SGS) is a narrowing of the subglottic airway, which is housed in the cricoid cartilage. The criterion standard for airway evaluation is direct laryngoscopy and direct bronchoscopy, while surgical therapies for subglottic stenosis (SGS) include serial endoscopic dilation, open reconstruction, the anterior cricoid split (ACS), single-stage laryngotracheoplasty with cartilage expansion, anterior and posterior cricoid splitting with costal cartilage grafts placed anteriorly and posteriorly, and partial cricotracheal resection. The image below shows an intraoperative endoscopic view of a normal subglottis.

Intraoperative endoscopic view of a normal subglot Intraoperative endoscopic view of a normal subglottis

The subglottic airway is the narrowest area of the airway, since it is a complete, nonexpandable, and nonpliable ring, unlike the trachea, which has a posterior membranous section, and the larynx, which has a posterior muscular section. The term subglottic stenosis (SGS) implies a narrowing that is created or acquired, although the term is applied to both congenital lesions of the cricoid ring and acquired subglottic stenosis (SGS). See the images below.

Grade III subglottic stenosis in an 18-year-old pa Grade III subglottic stenosis in an 18-year-old patient following a motor vehicle accident. The true vocal cords are seen in the foreground. Subglottic stenosis is seen in the center of the picture.
Endoscopic view of the true vocal cords in the for Endoscopic view of the true vocal cords in the foreground and the elliptical congenital subglottic stenosis (SGS) in the center of the picture.
Subglottic view of very mild congenital subglottic Subglottic view of very mild congenital subglottic stenosis. Laterally, the area looks only slightly narrow. When endotracheal tubes were used to determine its size, it was found to be 30% narrowed.
Subglottic view of congenital elliptical subglotti Subglottic view of congenital elliptical subglottic stenosis.
Granular subglottic stenosis in a 3-month-old infa Granular subglottic stenosis in a 3-month-old infant that was born premature, weighing 800 g. The area is still granular following cricoid split. This patient required tracheotomy and eventual reconstruction at age 3 years. True vocal cords are shown in the foreground (slightly blurry).
Intraoperative laryngeal view of the true vocal co Intraoperative laryngeal view of the true vocal cords of a 9-year-old boy. Under the vocal cords, a subglottic stenosis can be seen.
This spiraling subglottic stenosis is not complete This spiraling subglottic stenosis is not complete circumferentially. Laser therapy was the treatment choice and was successful after 2 laser treatments.
Continued lasering of the subglottic stenosis. The Continued lasering of the subglottic stenosis. The reflected red light is the aiming beam for the CO2 laser.
Postoperative view. Some mild residual posterior s Postoperative view. Some mild residual posterior subglottic stenosis remains, but the child is asymptomatic and the airway is open overall.
Preoperative view of a 4-month-old infant with acq Preoperative view of a 4-month-old infant with acquired grade III subglottic stenosis from intubation. Vocal cords are in the foreground.
A close-up view. A close-up view.
Postoperative view. The patient had been intubated Postoperative view. The patient had been intubated for 1 week and extubated for 1 week.
A subglottic view following dilation with an endot A subglottic view following dilation with an endotracheal tube to lyse the thin web of scar and a short course (5-day) treatment with oral steroids.
Postoperative view of a 4-month-old infant with su Postoperative view of a 4-month-old infant with subglottic stenosis following cricoid split. Notice very mild recurrence of scaring at the site of previous scar. Overall, the airway is open and patent. The anterior superior area can be seen, with a small area of fibrosis where the cricoid split previously healed.
Preoperative subglottic view of a 2-year-old patie Preoperative subglottic view of a 2-year-old patient with congenital and acquired vertical subglottic stenosis.

Workup

Diagnostic procedures include the following:

  • Flexible fiberoptic nasopharyngoscopy and laryngoscopy
  • Flexible endoscopy
  • Rigid laryngoscopy and bronchoscopy

Certain radiographic examinations can help in obtaining a diagnosis and determining the severity of the disease, and fluoroscopy is often performed in children with symptoms of airway obstruction.

Management

Surgical therapies include the following:

  • Serial endoscopic dilation with or without steroid injections - For mild or granular subglottic stenosis (SGS)
  • Open reconstruction of subglottic stenosis - Often may be unnecessary for subglottic stenosis (SGS) classified as grades I and II on the Myers and Cotton scale (ie, as much as 70% obstruction of the subglottic airway)
  • Anterior cricoid split - Children who are likely to benefit from this procedure include the following: (1) patient weight of more than 1500 g, (2) failure to extubate in identified subglottic stenosis (SGS), (3) oxygen requirement of less than 30%, (4) no active respiratory infection, and (5) good pulmonary and cardiac function
  • Single-stage laryngotracheoplasty with cartilage expansion
  • Anterior and posterior grafting - Anterior and posterior cricoid splitting with costal cartilage grafts placed anteriorly and posteriorly; has been successful in expanding the lumen and allowing decannulation in cases of severe subglottic stenosis (grade III-IV)
  • Partial cricotracheal resection - The best candidates for this procedure are patients with severe subglottic stenosis (grade III-IV) without associated glottic pathologic conditions and with a margin of at least 4 mm in the healthy airway below the vocal folds and above the stenosis

History of the Procedure

Early in the 20th century, acquired subglottic stenosis (SGS) was usually related to trauma or infection from syphilis, tuberculosis, typhoid fever, or diphtheria. Also, children often had tracheotomies placed that caused laryngeal stenosis. In this era, attempted laryngeal dilation failed as a treatment for subglottic stenosis (SGS).

Acquired subglottic stenosis (SGS) occurred increasingly in the late 1960s through the 1970s, after McDonald and Stocks (in 1965) introduced long-term intubation as a treatment method for neonates in need of prolonged ventilation for airway support. The increased incidence of subglottic stenosis (SGS) focused new attention on the pediatric larynx, and airway reconstruction and expansion techniques were developed.[1, 2, 3]

Surgery without cartilage expansion

In 1971, Rethi and Rhan described a procedure for vertical division of the posterior lamina of the cricoid cartilage with Aboulker stent placement. A metal tracheotomy tube was attached to the Aboulker stent with wires, and the anterior cartilaginous incision was closed. In 1974, Evanston and Todd described success with a castellated incision of the anterior cricoid cartilage and upper trachea, which was sewn open, and a stent made of a rolled silicone sheet was placed in it for 6 weeks. In 1980, Cotton and Seid described a procedure, in which tracheotomy is avoided, called the anterior cricoid split (ACS). The procedure was designed for use in neonates (usually, those born prematurely) with anterior glottic stenosis or SGS who had airway distress after extubation. The cricoid ring was divided anteriorly and a laryngofissure was created in an attempt to expand the airway without a tracheotomy. Holinger et al also described success with this procedure in 1987.

Surgery with cartilage-grafting reconstruction

In 1974, Fearon and Cotton described the successful use of cartilage grafts to enlarge the subglottic lumen in African green monkeys and in children with severe laryngotracheal stenosis.[4] All augmentation materials were evaluated, including thyroid cartilage, septal cartilage, auricular cartilage, costal cartilage, hyoid bone, and sternocleidomastoid myocutaneous flaps. After significant work, it appeared that costal cartilage grafts had the highest success rate.

In the 1980s, Cotton reported his experience with laryngeal expansion with cartilage grafting. His success rates depended on degree of stenosis: More severe forms of stenosis required multiple surgical procedures. Cotton used the Aboulker stent.

In 1991, Seid et al described a form of single-stage laryngotracheal reconstruction in which cartilage was placed anteriorly to expand the subglottis and upper trachea to avoid a tracheotomy.[5]

In 1992, Cotton et al described a 4-quadrant cricoid split, along with anterior and posterior grafting.[6] In 1993, Zalzal reported 90% decannulation with any degree of subglottic stenosis (SGS) with his first surgical procedure.[7] Zalzal customized the reconstruction on an individual basis, and most patients received Aboulker stents for stabilization.

Cricotracheal resection

In 1993, Monnier described partial cricotracheal resection with primary anastomoses for severe SGS, since grade III and grade IV SGS (ie, severe SGS) often requires multiple (3-4) surgical augmentations for decannulation. In 1997, Cotton described his experience with the procedure, reporting a decannulation rate higher than 90% for primary and rescue cricotracheal resection.

Problem

Subglottic stenosis (SGS) is narrowing of the subglottic lumen. Subglottic stenosis (SGS) can be acquired or congenital. Acquired subglottic stenosis (SGS) is caused by either infection or trauma, as seen in the images below. Congenital subglottic stenosis (SGS) has several abnormal shapes.

Grade III subglottic stenosis in an 18-year-old pa Grade III subglottic stenosis in an 18-year-old patient following a motor vehicle accident. The true vocal cords are seen in the foreground. Subglottic stenosis is seen in the center of the picture.
Granular subglottic stenosis in a 3-month-old infa Granular subglottic stenosis in a 3-month-old infant that was born premature, weighing 800 g. The area is still granular following cricoid split. This patient required tracheotomy and eventual reconstruction at age 3 years. True vocal cords are shown in the foreground (slightly blurry).
Intraoperative laryngeal view of the true vocal co Intraoperative laryngeal view of the true vocal cords of a 9-year-old boy. Under the vocal cords, a subglottic stenosis can be seen.
This spiraling subglottic stenosis is not complete This spiraling subglottic stenosis is not complete circumferentially. Laser therapy was the treatment choice and was successful after 2 laser treatments.
Continued lasering of the subglottic stenosis. The Continued lasering of the subglottic stenosis. The reflected red light is the aiming beam for the CO2 laser.
Postoperative view. Some mild residual posterior s Postoperative view. Some mild residual posterior subglottic stenosis remains, but the child is asymptomatic and the airway is open overall.
Preoperative view of a 4-month-old infant with acq Preoperative view of a 4-month-old infant with acquired grade III subglottic stenosis from intubation. Vocal cords are in the foreground.
A close-up view. A close-up view.
Postoperative view. The patient had been intubated Postoperative view. The patient had been intubated for 1 week and extubated for 1 week.
A subglottic view following dilation with an endot A subglottic view following dilation with an endotracheal tube to lyse the thin web of scar and a short course (5-day) treatment with oral steroids.
Postoperative view of a 4-month-old infant with su Postoperative view of a 4-month-old infant with subglottic stenosis following cricoid split. Notice very mild recurrence of scaring at the site of previous scar. Overall, the airway is open and patent. The anterior superior area can be seen, with a small area of fibrosis where the cricoid split previously healed.
Preoperative subglottic view of a 2-year-old patie Preoperative subglottic view of a 2-year-old patient with congenital and acquired vertical subglottic stenosis.

Holinger evaluated 29 pathological specimens obtained in children with congenital cricoid anomalies. Half of these children had an elliptical cricoid cartilage, as shown below, which Tucker first described in 1979.

Subglottic view of congenital elliptical subglotti Subglottic view of congenital elliptical subglottic stenosis.

Elliptical cricoid cartilage was the most commonly observed congenital abnormality. Other observed abnormalities included a flattened anterior shape, a thickened anterior cricoid, and a submucosal posterior laryngeal cleft.

Epidemiology

Frequency

The frequency of congenital subglottic stenosis (SGS) is unknown.

The incidence of acquired subglottic stenosis (SGS) has greatly decreased over the past 40 years. In the late 1960s, when endotracheal intubation and long-term ventilation for premature infants began, the incidence of acquired subglottic stenosis (SGS) was as high as 24% in patients requiring such care. In the 1970s and 1980s, estimates of the incidence of subglottic stenosis (SGS) were 1-8%.

In 1998, Choi reported that the incidence of subglottic stenosis (SGS) had remained constant at the Children's National Medical Center in Washington, DC; it was approximately 1-2% in children who had been treated in the neonatal ICU.[8] Walner recently reported that, among 504 neonates who were admitted to the level III ICU at the University of Chicago in 1997, 281 were intubated for an average of 11 days, and in no patient did subglottic stenosis (SGS) develop over a 3-year period. In 1996, a report from France also described no incidence of subglottic stenosis (SGS) in the neonatal population who underwent intubation with very small endotracheal tubes (ie, 2.5-mm internal diameter) in attempts to prevent trauma to the airway.

Morbidity

Using the Kids’ Inpatient Database (KID), Arianpour et al found that in addition to gastroesophageal reflux (GER), comorbidities more likely to be diagnosed in inpatients aged 20 years or younger with acquired subglottic stenosis (SGS) include trisomy 21, asthma, and additional upper airway anomalies. However, the chance of prematurity and dehydration was indicated to be lower in pediatric acquired SGS.[9]

Etiology

The cause of congenital subglottic stenosis (SGS) is in utero malformation of the cricoid cartilage.

The etiology of acquired subglottic stenosis (SGS) is related to trauma of the subglottic mucosa. Injury can be caused by infection or mechanical trauma, usually from endotracheal intubation but also from blunt, penetrating, or other trauma. Historically, acquired subglottic stenosis (SGS) has been related to infections such as tuberculosis and diphtheria.[10] Over the past 40 years, the condition has typically been related to mechanical trauma.

Factors implicated in the development of subglottic stenosis (SGS) include the size of the endotracheal tube relative to the child's larynx, the duration of intubation, the motion of the tube, and repeated intubations. Additional factors that affect wound healing include systemic illness, malnutrition, anemia, and hypoxia. Local bacterial infection may play an important role in the development of subglottic stenosis (SGS). Gastroesophageal reflux (GER) may play an adjuvant role in the development of subglottic stenosis (SGS) because it causes the subglottis to be continually bathed in acid, which irritates and inflames the area and prevents it from healing correctly. A systemic or gastrointestinal allergy may cause the airway to be more reactive, creating a greater chance of developing stenosis.

A study by Schweiger et al indicated that in children who have been intubated, undersedation increases the risk that subglottic stenosis will develop. The study, of children aged 30 days to 5 years who underwent endotracheal intubation, found that the percentage of COMFORT behavior (COMFORT-B) scale scores between 23 and 30 (indicating undersedation) was greater in children with subglottic stenosis than in children without the condition (15.8% vs 3.65%, respectively).[11]

Pathophysiology

Acquired subglottic stenosis (SGS) is often caused by endotracheal intubation. Mechanical trauma from an endotracheal tube, as it passes through or remains for long periods in the narrowed neonatal and subglottic airway, can lead to mucosal edema and hyperemia. These conditions then can progress to pressure necrosis of the mucosa. These changes have been observed within a few hours of intubation and may progress to expose the perichondrium of the cricoid cartilage. Infection of the perichondrium can result in a subglottic scar. This series of events can be hastened if an oversized endotracheal tube is used. Always check for an air leak after placing an endotracheal tube because of the risk of necrosis of the mucosa, even in short surgical procedures. This practice is common among anesthesiologists. Usually, the pressure of the air leak should be less than 20 cm of water, so that no additional pressure necrosis occurs in the mucosa of the subglottis.

A study by Morrison et al indicated that in idiopathic subglottic stenosis (SGS), scar fibroblast production is driven by interleukin 17A (IL-17A). In addition, according to the investigators, IL-17A promotes extracellular matrix development by synergizing with transforming growth factor β1. Moreover, by prompting chemokine and cytokine production via direct scar fibroblast stimulation, IL-17A encourages the recruitment and differentiation of myeloid cells.[12]

Presentation

History

Children with subglottic stenosis (SGS) have an airway obstruction that may manifest in several ways. In neonates, subglottic stenosis (SGS) may manifest as stridor and obstructive breathing after extubation that requires reintubation. At birth, intubation in most full-term neonates should be performed with a 3.5-mm pediatric endotracheal tube. If a smaller-than-appropriate endotracheal tube must be used, narrowing of the airway may be present, which could suggest subglottic stenosis (SGS).

The stridor in subglottic stenosis (SGS) is usually biphasic. Biphasic stridor can be associated with glottic, subglottic, and upper tracheal lesions. Inspiratory stridor usually is associated with supraglottic lesions; expiratory stridor usually is associated with tracheal, bronchial, or pulmonary lesions.

The level of airway obstruction varies depending on the type or degree of subglottic stenosis (SGS). In mild subglottic stenosis (SGS), only exercise-induced stridor or obstruction may be present. In severe subglottic stenosis (SGS), complete airway obstruction may be present and may require immediate surgical intervention.

Depending on the severity, subglottic stenosis (SGS) can cause patients to have decreased subglottic pressure and a hoarse or a weak voice. Hoarseness or vocal weakness also can be associated with glottic stenosis and vocal cord paresis or paralysis.

Always ask about a history of recurrent croup. A child with an otherwise adequate but marginal airway can become symptomatic with the development of mucosal edema associated with a routine viral upper respiratory infection (URI). Children with these conditions may have subglottic narrowing and an evaluation of the airway is appropriate.

Always assess the history of GER disease (GERD). If present, always evaluate GERD prior to surgical intervention. A child who eventually has a diagnosis of subglottic stenosis (SGS) often has a history of either laryngotracheal trauma or intubation and ventilation. Frequently, these patients were born prematurely, have bronchopulmonary dysplasia, and may require oxygen administration. The degree of pulmonary disease and the amount of oxygen the child requires may affect the ability to perform decannulation. Prior to surgical intervention, the child should not require a substantial oxygen supplementation.

Physical examination

The physical examination varies depending on the degree of subglottic stenosis (SGS) present. Auscultate the child's lung fields and neck to assess any symptoms of airway obstruction and to evaluate pulmonary function. Completely evaluate the head and neck, and identify associated facial abnormalities such as cleft palate, choanal atresia, retrognathia, and facial deformities. Evaluate the child's initial overall appearance, and ask the following questions:

  • Is the child comfortable?

  • Does the child have difficulty breathing?

  • Does the child have difficulty breathing when emotionally upset?

  • Does the child have any suprasternal, substernal, or intercostal retractions?

  • Does the child have any nasal flaring?

  • Is the voice normal? Is it weak? Is the voice breathy?

  • Does the child have stridor? If so, what is the nature of the stridor (ie, inspiratory, expiratory, or biphasic)?

  • What is the child's neurologic status?

  • Does the child have a tracheotomy? Can the patient occlude the tracheotomy and still breathe without laboring?

Indications

Staging

Surgical reconstruction is performed on the basis of the symptoms, regardless of SGS grade. Children with grade I and mild grade II subglottic stenosis (SGS) often do not require surgical intervention.

Myers and Cotton devised a classification scheme for grading circumferential subglottic stenosis from I-IV, which is established endoscopically and by using noncuffed pediatric endotracheal tubes of various sizes and sizing the airway. The scale describes stenosis as a percent of area that is obstructed.

The system contains 4 grades, as follows:

  • Grade I - Obstruction of 0-50% of the lumen obstruction

  • Grade II - Obstruction of 51-70% of the lumen

  • Grade III - Obstruction of 71-99% of the lumen

  • Grade IV - Obstruction of 100% of the lumen (ie, no detectable lumen)

The percentage of stenosis is evaluated by using endotracheal tubes of different sizes. The largest endotracheal tube that can be placed with an air leak less than 20 cm of water pressure is recorded and evaluated against a scale that has previously been constructed by Myers and Cotton, as depicted below.

Granulation tissue (superior center portion of the Granulation tissue (superior center portion of the picture) that occurred at the graft site of a laryngotracheal reconstruction performed with an anterior graft.

This grading system applies mainly to circumferential stenosis and does not apply to other types of subglottic stenosis (SGS) or combined stenoses, although it can be used to obtain a rough estimate. Typically, children with grade I, as shown in the image below, or mild grade II stenosis do not require surgical intervention. Children with these conditions may have intermittent airway symptoms, especially when infection or inflammation causes mucosal edema.

Subglottic view of very mild congenital subglottic Subglottic view of very mild congenital subglottic stenosis. Laterally, the area looks only slightly narrow. When endotracheal tubes were used to determine its size, it was found to be 30% narrowed.

Indications

Surgical intervention may be avoided if periods of airway obstruction are rare and can be treated on an inpatient or outpatient basis with anti-inflammatory and vasoconstrictive agents, such as oral, intravenous, or inhaled steroids and inhaled epinephrine (racemic treatment). If children with these conditions continue to have intermittent or persistent stridor and airway obstructive symptoms when they are well, or if they frequently become ill, surgical intervention may be necessary.

Development of upper respiratory symptoms during routine infections can indicate whether a child with subglottic stenosis (SGS) requires surgical reconstruction. Viral infections of the upper respiratory tract can create swelling in any area of the respiratory epithelium from the tip of the nose to the lungs. If a child with subglottic stenosis (SGS) has a cold and/or bronchitis but no significant symptoms of stridor or upper airway obstruction, the airway may be large enough to tolerate stress, and reconstruction may not be needed. A history of recurrent croup suggests subglottic stenosis (SGS).

Occasionally, older children have exercised-induced airway obstruction. At evaluation, these children may have grade I or grade II subglottic stenosis (SGS). Expansion of the airway with cartilage augmentation may allow them to lead a healthy and active lifestyle.

Children with grade III or grade IV subglottic stenosis (SGS) need one or more of the forms of surgical treatment discussed in Surgical therapy.

Although croup, bacterial infection, GERD, and bronchopulmonary dysplasia may occur or be involved in the development of subglottic stenosis (SGS), a history of prolonged endotracheal tube intubation is the most common factor seen in patients with subglottic stenosis (SGS) that requires surgical correction.

Relevant Anatomy

The subglottis is defined as the area of the larynx housed by the cricoid cartilage that extends from 5 mm beneath the true vocal cords to the inferior aspect of the cricoid ring, depicted in the image below. Because of the proximity and close relationship of the subglottis to the glottic larynx, glottic stenosis often can be present with subglottic stenosis (SGS). When SGS is corrected surgically, good voice quality can be preserved by not violating the true vocal cords if they are uninvolved in the disease process.

Intraoperative endoscopic view of a normal subglot Intraoperative endoscopic view of a normal subglottis

When creating the entry incision into the airway in an isolated subglottic stenosis (SGS), divide the cricoid cartilage, upper 2 tracheal rings, and the inferior third to half of the laryngeal cartilage in the midline; avoid dividing the anterior commissure. However, if the disease dictates or if exposure for repair cannot be obtained without dividing the anterior commissure, carefully perform the procedure. Endoscopic guidance can help in preventing injury to the glottic larynx.

If a laryngofissure is required for glottic stenosis or to gain access to the posterior aspect of the stenosis for suturing of the posterior graft, care must be taken to identify the anterior commissure and correctly put it back into place. Once the laryngofissure is created in the midline, immediately suture the anterior aspect of the true vocal chords near the anterior commissure to the laryngeal cartilage with a 6-0 monofilament suture such as polydioxanone (PDS) or Monocryl. This procedure helps prevent anterior commissure from becoming blunted and helps mark approximately where it should be once the laryngofissure is closed.

When dividing the posterior cricoid lumen, note that the esophagus is immediately adjacent and posterior to it. Take care to avoid injuring the esophagus when completely dividing the posterior cricoid lamina during cartilage augmentation.

The recurrent laryngeal nerves enter the larynx in the posterior lateral portion of the cricoid ring. When surgery is performed in the midline, the recurrent laryngeal nerves should be far enough away from an anterior division to prevent injury. Any surgical procedure in which the lateral cricoid is divided could jeopardize the laryngeal nerve and result in paresis or paralysis of the true vocal cords. In the cricotracheal resection procedure, no attempt is made to identify the recurrent laryngeal nerves because of dense scarring. This lack of identification has resulted in some reported cases of paresis of the true vocal cord.

Contraindications

No specific absolute contraindications to the laryngotracheal reconstruction procedure exist. However, if general anesthesia is absolutely contraindicated, surgical correction of subglottic stenosis (SGS) cannot be performed.

A relative contraindication to reconstruction of a narrow subglottis is present in children who have a tracheotomy and subglottic stenosis (SGS) but need a tracheotomy for other purposes (eg, access for suctioning secretions caused by chronic aspiration) or in those who have airway collapse or obstruction in the nasal cavity, nasopharynx, oral cavity, oropharynx, supraglottic larynx, or trachea that cannot be repaired. However, if severe or complete laryngeal obstruction exists and if the child might be able to vocalize if the airway were surgically corrected, reconstruction may be beneficial, despite the need to maintain the tracheotomy tube. Severe GER is another relative contraindication. Once GER is treated successfully (medically or surgically) or resolves on its own, reconstruction can be considered. An additional relative contraindication to airway reconstruction is pulmonary or neurological function that is inadequate to withstand tracheotomy decannulation.

Regardless of the cause of subglottic stenosis (SGS), it is usually best to delay reconstructive efforts in children who have reactive or granular airways, shown below, until the reactive nature of the patient's condition subsides.

Granular subglottic stenosis in a 3-month-old infa Granular subglottic stenosis in a 3-month-old infant that was born premature, weighing 800 g. The area is still granular following cricoid split. This patient required tracheotomy and eventual reconstruction at age 3 years. True vocal cords are shown in the foreground (slightly blurry).
 

Workup

Laboratory Studies

See the list below:

  • Specific laboratory studies are not required.

Imaging Studies

See the list below:

  • The criterion standard for evaluation of the airway is direct laryngoscopy and direct bronchoscopy.

  • Certain radiographic examinations can help in obtaining a diagnosis and determining the severity of the disease. Usually, the initial radiographic study used to evaluate a child with airway obstruction is anteroposterior and lateral plain neck radiography. Frequently, in a child with subglottic stenosis (SGS), the subglottis appears narrowed and peaked; this is often described as a steeple sign. In a patient with a thin web subglottic stenosis (SGS), a lateral plain film radiograph may show a faint line.

  • Fluoroscopy is often performed in children with symptoms of airway obstruction.

    • Fluoroscopy can be used to diagnose lesions of the larynx and trachea.

    • When a barium-enhanced esophagram is added to the procedure, vascular malformations, along with GERD, may be ruled out.

  • Computed tomography (CT) and magnetic resonance imaging (MRI) scans are not often used in the primary evaluation of subglottic stenosis (SGS).

Other Tests

Investigate any indication of GERD. Walner showed that children with subglottic stenosis (SGS) have a 3-fold increase in GERD compared with the general pediatric population.

Currently, the best test in evaluating for GER is dual-channel pH probe testing. One probe is placed above the lower esophageal sphincter, and another is placed at the area of the cricopharyngeus near the larynx.

Walner and Cotton recommend treating GER for 1 month before and 12 months after airway reconstructive surgery, even if only mild disease is present.

If moderate or severe GERD is diagnosed, start medical therapy and confirm disease resolution with another pH probe test prior to surgery. Do not perform laryngeal reconstruction until GER has resolved.

If reconstruction is being considered, pediatric laryngologists frequently perform tests to rule out GER, even in the absence of symptoms, because the disease may affect the outcome.

One concern suggests that an "allergic" esophagitis may exist and affect the outcome of surgery. To evaluate for this entity, an esophagogastroduodenoscopy (EGD) is performed with biopsies of the proximal and distal esophagus, stomach, and duodenum. If more than 15 eosinophils are found in the mucosa per high power field, the patient may have "allergic" esophagitis. Evaluation and treatment for GERD must have taken place prior to this evaluation, since reflux may elicit eosinophils as well. If "allergic" esophagitis is discovered, then treatment with weeks to months of oral steroids or orally applied inhaled steroids is performed to help diminish the affects of the disease and possibly allow for a better success rate of laryngeal reconstruction.

Diagnostic Procedures

In a child with mild or moderate airway obstruction, perform flexible fiberoptic nasopharyngoscopy and laryngoscopy in the clinic or the emergency department (ED). If extreme airway obstruction exists or if an active supraglottic infectious process is suspected in a young child, flexible endoscopy may be deferred in favor of formal rigid bronchoscopy in the operating room (OR). However, flexible fiberoptic nasopharyngoscopy may be performed in a controlled setting in the OR, because determination of the nature of the supraglottis and glottis in awake unsedated patients is crucial. The procedures are described as follows.

Flexible fiberoptic nasopharyngoscopy and laryngoscopy

During flexible fiberoptic nasopharyngoscopy and laryngoscopy, topical anesthesia and decongestion can be accomplished in older infants and children with topical Afrin and lidocaine. A 3-mm endoscope can be used, even in an infant. Pass the endoscope into both nasal cavities to access pyriform aperture stenosis, midnasal stenosis, choanal atresia or stenosis, lesions of the nose and nasopharynx, and the adenoid pad.

Pass the endoscope into the superior oropharynx and hypopharynx. The hypopharynx and larynx can be assessed. Identify the structure and position of the supraglottis. Evaluate the epiglottis and arytenoids for malacia or stenosis. Evaluate the position and movement of the true vocal cords. Evaluate edema or erythema of the true vocal cords, epiglottis, and arytenoids.

Flexible endoscopy

This can be performed with the patient in the supine or sitting position. The supine position often results in the obstruction of certain supraglottic processes. If the goal is to obtain the best visualization of the true vocal cords and supraglottis, place a child (even an infant) in the sitting position with his or her neck extended.

If the child is older, the voice can be evaluated, and videostroboscopy can be performed to assess the vocal cord waveform and vocal cord mobility.

Occasionally, the subglottis can be visualized with flexible endoscopy; however, rigid laryngoscopy and bronchoscopy are the safest procedures and offer the best visualization for the subglottis and tracheobronchial tree.

Rigid laryngoscopy and bronchoscopy

Rigid laryngoscopy and bronchoscopy is the best single test for evaluating airway obstruction in children. The otolaryngologist must have knowledge of the pediatric airway, and the OR must have adequate bronchoscopes and telescopes of various sizes. Prepare all equipment for bronchoscopy, including laryngoscopes, light sources, video documentation equipment, telescopes, and bronchoscopes prior to the child's arrival in the OR. Throughout the procedure, maintain good communication between anesthesiologists, surgical nursing staff, and physicians, so that any potential airway obstruction can be quickly assessed and addressed.

Do not further injure the pediatric airway—this point is of paramount importance. Use the smallest bronchoscope or telescope alone for evaluation of the subglottis in a child who does not require ventilation throughout the procedure. This practice allows good visualization without iatrogenic injury to the area. If ventilation is required throughout the evaluation, use a bronchoscope-telescope combination.

If a child has a tracheotomy or is not in extreme distress, the child can breathe spontaneously and inhale oxygen and anesthetics through an endotracheal tube in the pharynx while the airways are visualized with a laryngoscope and large telescope. Frequently, the true vocal cords are anesthetized with lidocaine prior to evaluation to help prevent laryngospasm.

Determine the size of the child's airway by using endotracheal tubes. Myers and Cotton have established a scale for subglottic stenosis (SGS) severity that is based on the child's age and the size of the endotracheal tube that can be placed in the airway with an air leak pressure of less than 20 cm of water.

Evaluate the subglottis and glottis for fixation, scarring, granulation, edema, paralysis or paresis, and other abnormalities. Evaluate the distance and caliber of the stenosis. Apply the Myer and Cotton staging system only to circumferential subglottic stenosis (SGS).[13] Glottic stenosis and SGS often coexist and must be considered when reconstruction is planned.

Evaluate the maturity of the stenosis. If a firm white scar is present, the stenosis is mature. If the stenosis has a granular or erythematous appearance, GERD, viral infection, allergic esophagitis, or another inflammatory process may be present.

Examine the area below the subglottis into the trachea and bronchi for secondary lesions. The suprastomal area is important because pathological stenosis or malacia can influence the choice of surgical procedure. In severe subglottic stenosis (SGS), viewing the suprastomal area requires the passage of a tiny telescope through a narrow subglottis or a telescope or bronchoscope through a tracheotomy site, if available.

 

Treatment

Medical Therapy

No known medical therapy for mature subglottic stenosis (SGS) exists. If a granular or immature subglottic stenosis (SGS) is noted, as shown in the image below, treatment of the inflammatory process with oral or inhaled steroids sometimes can decrease the severity of disease. Findings from animal studies have shown that treatment with antibiotics and steroids can help improve an immature or granular subglottic stenosis (SGS); however, the optimal treatment duration is unknown. Evaluate each case on an individual basis. Once subglottic stenosis (SGS) is mature, medical therapy is almost always unsuccessful. However, suspected GER must receive aggressive medical treatment for optimal surgical results.

Granular subglottic stenosis in a 3-month-old infa Granular subglottic stenosis in a 3-month-old infant that was born premature, weighing 800 g. The area is still granular following cricoid split. This patient required tracheotomy and eventual reconstruction at age 3 years. True vocal cords are shown in the foreground (slightly blurry).

Surgical Therapy

Endoscopic procedures

For mild or granular subglottic stenosis (SGS), investigators have reported success with serial endoscopic dilation with or without steroid injections. Healy popularized the use of the carbon dioxide laser as an option for soft circumferential subglottic stenosis (SGS).[14] This procedure involves making incisions in 4 quadrants, followed by dilation. This technique is best used in conjunction with steroids when an immature or granular subglottic stenosis (SGS) is present. Normally, use of a laser causes recurrence of the scar in a mature stenosis; however, in unusual types of mature subglottic stenosis (eg, spiraling subglottic stenosis), improvement may be accomplished with a few serial carbon dioxide laser excisions, shown below.

Intraoperative laryngeal view of the true vocal co Intraoperative laryngeal view of the true vocal cords of a 9-year-old boy. Under the vocal cords, a subglottic stenosis can be seen.
This spiraling subglottic stenosis is not complete This spiraling subglottic stenosis is not complete circumferentially. Laser therapy was the treatment choice and was successful after 2 laser treatments.
Continued lasering of the subglottic stenosis. The Continued lasering of the subglottic stenosis. The reflected red light is the aiming beam for the CO2 laser.
Postoperative view. Some mild residual posterior s Postoperative view. Some mild residual posterior subglottic stenosis remains, but the child is asymptomatic and the airway is open overall.

In addition, topical application of mitomycin has been used in an attempt to inhibit scars from reforming after an endoscopic lysis of either mature or granular subglottic stenosis (SGS). Mitomycin is an antineoplastic agent that inhibits fibroblast proliferation and activity. Varying reports have shown both benefit and no benefit when used topically for subglottic stenosis (SGS). When evaluating the studies, evidence suggests that mitomycin is beneficial in both acute granular stenosis and mature stenosis, although it may work better in acute trauma to the subglottis that results in a fresh or granula scar. A controlled study on the use of mitomycin as an adjunct to laryngotracheal reconstruction, as well as several animal studies, have show no benefit to its use in mature stenosis. Hueman and Simpson, in December 2005, reported that 4.7% of patients developed local complications of fibrinous debris at the operative site, with no mention of any system complications.[15]

A prospective study by Avelino et al indicated that in children who undergo balloon laryngoplasty for acquired subglottic stenosis, success is predicted by the presence of acute stenosis and of a less severe grade of stenosis, as well as by younger age and the absence of tracheotomy. In the study, which included 17 patients with acute subglottic stenosis and 31 with chronic stenosis, the success rate for balloon laryngoplasty was 100% for the acute patients and 39% for children with the chronic condition.[16]

A retrospective study by Maresh et al found that endoscopic balloon dilation is less likely to be successful in severe (grade 3 or 4) pediatric subglottic stenosis compared with laryngotracheoplasty, with initial treatment with balloon dilation failing in 13 out of 13 patients (100%) with severe stenosis and in 4 out of 14 patients (29%) with grade 1 or 2 stenosis.[17]

Open reconstruction of subglottic stenosis

Base the approach to open reconstruction of subglottic stenosis (SGS) on the location and degree of scarring. Reconstruction often may be unnecessary for subglottic stenosis (SGS) classified as grades I and II on the Myers and Cotton scale (ie, as much as 70% obstruction of the subglottic airway). When surgery is necessary on the basis of the severity of symptoms, perform an open reconstruction in mature circumferential subglottic stenosis (SGS). The surgical technique depends on adjacent areas of scarring and on the location and appearance of subglottic stenosis (SGS). For severe subglottic stenosis (SGS), classified as grades III and IV (ie, >70% luminal obstruction), laryngeal expansion is almost always necessary.

The goals of open reconstruction are decannulation or resolution of symptoms, with preservation of the voice by expanding the subglottic airway and stabilizing the expanded frame.

Various procedures for treating subglottic stenosis (SGS) include the following: (1) anterior cricoid split (ACS); (2) single staged procedure: anterior cartilaginous grafting with costal, thyroid, or auricular cartilage[18] ; (3) multistaged procedure applying (a) anterior and posterior cartilage grafting, usually with costal cartilage, (b) anterior cartilaginous grafting with a posterior cricoid split and stent placement, (c) posterior grafting with costal cartilage, and (d) anterior and posterior costal cartilage with lateral cricoid splits; and (4) cricotracheal resection.

Anterior cricoid split

In 1980, Cotton and Seid described the use of anterior cricoid split (ACS) to avoid tracheotomy in neonates with SGS, good pulmonary and cardiac function, and airway obstructive symptoms after extubation. Anterior cricoid split (ACS) allows decompression of the edematous submucosal glands of the subglottis and thus, expansion of the airway.[1]

Criteria have been developed to identify the children who are likely to benefit from anterior cricoid split (ACS). These include the following: (1) patient weight of more than 1500 g, (2) failure to extubate in identified subglottic stenosis (SGS), (3) oxygen requirement of less than 30%, (4) no active respiratory infection, and (5) good pulmonary and cardiac function.

Transport the already intubated child from the ICU, and make horizontal incisions over the cricoid cartilage. Divide the strap muscles in the midline, and identify the thyroid cartilage, costal cartilage, and upper tracheal rings, shown below.

An intraoperative view of a split cricoid in a pat An intraoperative view of a split cricoid in a patient with elliptical congenital subglottic stenosis. The open airway can be seen in the center of the picture. The wound extends to the inferior one third of the thyroid cartilage.

Place Prolene stay sutures (4-0) around each side of the anterior component of the cricoid ring. Use a double-sided beaver blade to make an incision in the cricoid ring as far as the tracheal rings and the inferior third to half of the laryngeal cartilage. Then, reintubate the child with an endotracheal tube appropriately sized for his or her age. Do not expand the airway more than necessary, since pressure on the mucosa and persistent subglottic stenosis (SGS) can result.

Loosely close the skin over the wound, and place a rubber band drain. Mark the Prolene sutures in the cricoid as left and right. Generally, leave the nasal tube in place for 7-10 days. If self-extubation occurs, reintubate from above. Should the endotracheal tube protrude through the airway into the neck during reintubation, the stay sutures can be lifted and crossed to block the cricoid split incision and to direct the endotracheal tube down the trachea. If this procedure is unsuccessful, the stay sutures can be pulled up to the neck and opened so that a tracheal or endotracheal tube can be placed in the airway until the child can be returned to the OR for intubation through the mouth.

Administer antibiotics and antireflux medication during the intubation period. Begin the administration of steroids 24 hours before extubation and continue for 48 hours afterwards. Usually, the tube can be removed after 7-10 days. If an air leak around the endotracheal tube is present with a pressure of less than 20 cm of water, extubation should be successful. If airway obstruction that is not amenable to medical therapy (including racemic treatments and steroids) occurs after extubation, return the patient to the OR for evaluation, or immediately reintubate in the ICU if necessary. Complications of anterior cricoid split (ACS) are unusual and include pneumothorax, pneumomediastinum, subcutaneous emphysema, wound infection, and persistent subglottic stenosis (SGS).

The images below were obtained in a 4-month-old infant born 3 months prematurely who required intubation and ventilation for 3 months.

Preoperative view of a 4-month-old infant with acq Preoperative view of a 4-month-old infant with acquired grade III subglottic stenosis from intubation. Vocal cords are in the foreground.
A close-up view. A close-up view.

She had a grade III SGS and underwent anterior cricoid split (ACS) with intubation and ventilation for 1 week in the ICU. The image below shows the subglottis 1 week after extubation.

Postoperative view. The patient had been intubated Postoperative view. The patient had been intubated for 1 week and extubated for 1 week.

The size of the larynx was determined with an endotracheal tube, and subsequent dilation of the soft mild restenosis is depicted in the image above and the image below.

A subglottic view following dilation with an endot A subglottic view following dilation with an endotracheal tube to lyse the thin web of scar and a short course (5-day) treatment with oral steroids.

The child received oral steroids for 5 days and underwent follow-up bronchoscopy, shown below, 2 weeks later.

Postoperative view of a 4-month-old infant with su Postoperative view of a 4-month-old infant with subglottic stenosis following cricoid split. Notice very mild recurrence of scaring at the site of previous scar. Overall, the airway is open and patent. The anterior superior area can be seen, with a small area of fibrosis where the cricoid split previously healed.

Single-stage laryngotracheoplasty with cartilage expansion

In 1991, Seid et al reported the use of single-stage laryngotracheoplasty (LTP).[5] Their approach to the airway resembles anterior cricoid split (ACS); however, instead of leaving the area anterior to the fibrosis, a piece of costal cartilage was placed. The procedure was performed in 13 patients with subglottic stenosis (SGS) grades I-IV. However, the procedure failed in a patient who had complete glottic and subglottic stenosis (grade IV). The researchers indicated that grade IV subglottic stenosis (SGS) was a contraindication to single-stage LTP. Two patients had grade III subglottic stenosis (SGS) and a successful result.

Seid et al stressed the postoperative course in these patients. Instead of leaving the endotracheal tube in place for 7-10 days, they checked the air leak surrounding the endotracheal tube on a daily basis and removed it when the pressure of the leak was less than 20 cm of water.[19]

The authors were also concerned about the transient weakness of the extremities caused by neuromuscular blockade and hydrocortisone. They used vecuronium and benzodiazepines for sedation. Aggressive pulmonary toilet was stressed, since wandering atelectasis can be present in a patient who is ventilator dependent for as many as 10 days. The authors stressed the repeated use of a full range of passive extremity motions to decrease the likelihood of transient muscle weakness during the period of induced paralysis for long-term intubation.

Seid et al believed that selection of patients was critical and that any child with difficulties in addition to subglottic stenosis (SGS); eg, tracheal problems, true vocal cord paralysis) was not a good candidate for single-stage LTP. The procedure could fail after extubation for reasons other than the newly repaired subglottic stenosis (SGS).

In 1995, Rothschild et al reviewed the effectiveness and complications of single-stage LTP.[20] In 104 patients from the Children's Hospital of Cincinnati, repair was successful in 86-92%, depending on the year of correction. The authors further reported that they did not use paralysis in their patients during the 5- to 10-day period of endotracheal tube placement; they used sedation with chlorohydrate and benzodiazepines instead. In fact, if the patient could tolerate nasotracheal intubation without much difficulty, they were allowed to engage in their usual activities, including eating, playing, and walking. (A modified cap placed on the endotracheal tube prevents crust formation in the tube and airway during these activities.)

Rothschild et al believed that younger children require heavier sedation and increased ventilation secondary to decreased respiratory effort. Neuromuscular paralysis usually was avoided. Among their 104 patients, the researchers found neuromuscular weakness in only one. They did not comment about the presence or absence of pulmonary atelectasis.

The average duration of endotracheal tube placement in their patients was 9 days. They did not explain why endotracheal tubes were in place longer than 10 days (as long as 26 d) in 37 children. Twenty-three children, however, had a posterior costal cartilage graft, which normally requires the use of stents for at least 2 weeks to stabilize the cartilaginous framework.

Seid and Cotton agreed that ICU staff who are knowledgeable and attentive are important to the success and safety of the procedure.

In 1991, Lusk and Muntz also described a single-stage LTP in which auricular cartilage is used for reconstruction when an anterior subglottic stenosis (SGS) is repaired. Patients had endotracheal tubes in place for 7-10 days, similar to the duration of intubation in patients in whom an ACS was performed. Lusk and Muntz sutured the cricoid to the strap muscles to help maintain airway patency; their success rate was similar to that of other procedures (ie, approximately 80-90%). This author's experience with the use of auricular cartilage has been less successful. If significant anterior subglottic stenosis (SGS) exists, use of cartilage that is rigid enough to maintain the splay of the cricoid cartilage usually is necessary to ensure continued expansion after extubation.

Zalzal added to the efficiency of the anterior cartilage single-stage procedure by describing the technique of carving the harvested rib into the shape of a boat with flanges on each end, as shown below.

Rib graft for reconstruction of subglottic stenosi Rib graft for reconstruction of subglottic stenosis. The diamond-shaped internal intraluminal component with perichondrium still present is seen on the top section of the rib and the shape of the rib is seen on the backside of the carved out diamond shape.
Anterior rib graft with a diamond shape. Note it m Anterior rib graft with a diamond shape. Note it measures approximately 1.7 mm in length. Intraluminal site is facing up. Flanges of rib are carved to remain on the outside of the trachea to prevent prolapse into the trachea.

In this technique, cartilage extends outside the lumen of the trachea, over the cricoid and tracheal rings, to help prevent the lumen from prolapsing into the airway.

Cartilage graft in place over the wound. Note exte Cartilage graft in place over the wound. Note external component of the graft still looks like a portion of the rib. The internal component has been carved in a diamond shape. This is an intraoperative photo. The cartilage graft was used in this patient for reconstruction.

With this technique (once any air leak is sealed during the surgery), extubation can be performed without fear of the cartilage requiring further stabilization or prolapsing into the airway.

After the procedure has been performed and the child has been admitted to the ICU, air leaks from the neck are checked on a daily basis. Usually, the air leak seals within 48-72 hours; extubation can be accomplished with confidence that the graft is stabilized. In this way, children can avoid the complications of long-term intubation mentioned above.

Reports of use of the superior section of the thyroid cartilage, as well as the septal cartilage, as grafting material exist. These materials, along with the auricular cartilage, usually do not provide much support. Instead, they act mainly as a patch over the divided area of the cricoid region. In these situations, the stent provides most of the force necessary to keep the lumen open while the surrounding area heals. Some of the other types of cartilage can be used in conjunction with ACS to improve that success rate of the procedure, which traditionally has been 70-80%.

Richardson and Inglis performed a prospective study to compare the cricoid split procedure with and without costal cartilage grafting for the treatment of acquired subglottic stenosis (SGS) in infants younger than 6 months in whom extubation in the ICU failed. The researchers found that results were improved in 90% of patients in whom cartilage was placed between the cricoid rings to expand the airway, compared with 56% in whom cartilage was not placed. This study was prospective and included only 20 patients, but its findings indicate that placing the lumen expander at the time of surgery greatly improves the likelihood that extubation succeeds and adequate airway is maintained.

Zalzal and Choi pointed out, however, that when the results of laryngotracheal reconstruction was evaluated in 48 patients aged 4 years or younger, success was decreased in children younger than 25 months compared with that of children aged 2-4 years.[21] (Note that the patients < 2 years had subglottic stenosis that was less severe than that of the older patients.) Zalzal and Choi still recommended laryngotracheal reconstruction in younger patients because the procedure may aid the child's speech and language development and help prevent tracheotomy complications.

Anterior and posterior grafting

For severe subglottic stenosis (grade III-IV), anterior and posterior cricoid splitting with costal cartilage grafts placed anteriorly and posteriorly has been effective in expanding the lumen and allowing decannulation. Most authors, including Zalzal and Cotton, agree that when a posterior graft is used, cartilage of sufficient strength must be placed posteriorly to keep the airway expanded.[22] Both Zalzal and Cotton have reported success rates higher than 90% with decannulation, frequently achieved with a single procedure. Occasionally, revision surgery is needed.

Often, the posterior graft is formed into an ellipse or elongated hexagon and placed so that the perichondrial side of the graft is flush with the mucosa of the posterior subglottic and tracheal wall. Occasionally, flanges can be fashioned on the posterior that can be placed posteriorly and outside the lumen in a manner similar to that of the boat graft (described by Zalzal), which is placed anteriorly. For a posterior graft, sutures to the posterior cartilage split are all placed individually prior to sliding the graft in position, as shown below, at which time the sutures can be tied. Sied described using fibrin glue in an animal study to keep a posterior graft in place, avoiding the arduous task of suturing it in.

Graft with all sutures in position. All the suture Graft with all sutures in position. All the sutures are placed prior to lowering the graft into position. Then, the sutures are tied.

Place the anterior graft in a similar fashion. Construction of the flanges on the anterior graft is not as critical as it is with a single-stage procedure, since children require stents for a minimum of 2 weeks. Usually, stents are used for 4-6 weeks when anterior and posterior grafts are placed and the tracheotomy is maintained. Once the stent is removed, follow-up bronchoscopies are performed to confirm the stenosis has not recurred before the patient is decannulated. Maintenance of a patent airway can be is evaluated with further bronchoscopies.

Usually, an Aboulker stent or Montgomery T tube (natively as depicted below, or cut to fit and used like an Aboulker stent, which are no longer commercially available) is used. See the images below.

Representative sample of varying sizes of Aboulker Representative sample of varying sizes of Aboulker stents (range of 3-15 mm). These stents are hollow and coated in Teflon.
Endoscopic view of Aboulker stent protruding throu Endoscopic view of Aboulker stent protruding through and above the true vocal cords. The arytenoids and epiglottic folds are seen.
A 7-mm Montgomery tracheotomy tube with caps A 7-mm Montgomery tracheotomy tube with caps

Other types of stents also have been used. Often, if the collapse or scar extends into the area of the tracheotomy site, longer-term stent placement is required with an Aboulker stent that is attached to a metal Holinger tracheotomy tube with wire, depicted below, or a Montgomery T tube.

Diagram of a long Aboulker stent wired to a metal Diagram of a long Aboulker stent wired to a metal Jackson tracheotomy tube.
A Jackson tracheotomy tube wired to a long Aboulke A Jackson tracheotomy tube wired to a long Aboulker stent.

Complications of short-term stent placement (4-6 wk), such as granulation tissue and scarring from the distal end of the short stent, can be prevented with longer-term techniques for stent use.

The surgical approach for anterior and posterior grafting is similar to the approach for ACS and anterior cartilage grafting. Specific care for the posterior cricoid split with or without grafting requires visualization of the esophagus after the posterior cricoid cartilage has been incised. During division, take care to spread the cartilage to identify the esophageal mucosa so that no inadvertent injury occurs. Additionally, make the incision in the midline to prevent injury to the recurrent laryngeal nerve and to ensure that an appropriate site is created for placement of the graft.

Partial cricotracheal resection

In Switzerland, Monnier first reported the use of partial cricotracheal resection in 31 pediatric patients with grade III and IV stenosis in whom decannulation with anterior-posterior grafting failed. The decannulation rate after cricotracheal resection was 97%. Cotton and others began to evaluate the use of cricotracheal resection because of failures with grade III and grade IV stenoses. Investigators in the "Cincinnati Experience" recently reported that decannulation occurred in 90% of children with refractory grade III and IV stenoses.

The best candidates for partial cricotracheal resection are patients with severe subglottic stenosis (grade III-IV) without associated glottic pathologic conditions and with a margin of at least 4 mm in the healthy airway below the vocal folds and above the stenosis. This space allows resection away from the glottic larynx, with anastomosis of healthy mucosa. Expect significant glottic edema to last 4-6 weeks; use a tracheotomy or T tube during the postoperative period to protect the airway until the edema resolves.

Perform the procedure with the patient under general anesthesia; the approach to the larynx and trachea is similar to that of other laryngotracheal reconstructive procedures. Vertically enter the airway with the beaver blade in the midline at the level of the cricoid. Make the incision superior to the inferior margin of the thyroid cartilage and inferior to the second tracheal ring. The superior extent of the stenosis can be defined at endoscopy while simultaneously and directly viewing the open wound, so that a precise view of the scarred subglottic segment can be achieved. Make a horizontal cut just above the superior extent of the stenosis, from the anterior aspect to the posterior aspect, stopping at the level of the cricothyroid joint. By staying anterior to the cricothyroid joint at this level, injury to the recurrent laryngeal nerve can be prevented.

Make lateral cuts inferior to the cricothyroid joints, and continue inferiorly through the lateral aspects of the cricoid cartilage to expose the posterior cricoid plate. Approach the inferior area of the stenosis, and place stay sutures in the distal normal tracheal segment. Incise the trachea just below the inferior aspect of the stenosis through the anterior lateral portions of the trachea down to the membranous tracheal wall, then dissected this from the esophageal wall at the superior aspect. Connect the superior incision and remove the segment. Next, suture the uninvolved part of the trachea to the anterior thyroid ala and the exposed posterior cricoid plate.

During the dissection from the inferior aspect to the superior aspect, take care to dissect in a perichondrial plane over the cricoid to prevent injury to the recurrent laryngeal nerve. If identification of the esophagus is difficult during this portion of the procedure, a palpable dilator can be placed in the esophagus to delineate the esophageal wall. Before anastomosis, remove the scar tissue from the inner aspect of the posterior cricoid plate by using a small curet or drill. Perform a hyoid release procedure to decrease tension at the suture line. In addition, dissect the trachea until 4-5 rings are mobilized to aid in decreasing tension on the suture line. In addition, place 2-3 additional tension-releasing sutures on the thyroid ala and the upper tracheal rings to help release tension from the suture line. Place Proline stitches (0-0) from the chin to the chest of the child to keep the head flexed for a week.

In an older child with minimal glottic involvement, a single-stage procedure can be performed with nasotracheal intubation of 7-10 days' duration. In younger children with more severe glottic involvement, a Montgomery T tube can be placed for 4-6 weeks. Take meticulous care to prevent plugging of the T tube and resultant airway obstruction. Stern and Cotton recently reported good results with decreased morbidity with T tubes in children.

Preoperative Details

The most important part of laryngotracheal reconstruction is the preoperative assessment. Assessment involves direct bronchoscopy with an evaluation of the severity and level of stenosis. If the stenosis is defined properly, the correct procedure can be used for the best surgical outcome.

Additionally, evaluate the child's pulmonary status and presence or absence of GERD. The pulmonary status, including the amount of oxygen required by the patient, may determine whether laryngotracheal reconstruction should be attempted.

Evaluate the neurologic status as well. Children who have severe neurologic delays may need a tracheotomy for other reasons than subglottic stenosis (SGS), such as access for suctioning of thick secretions or to bypass obstruction from a malacic pharynx or supraglottic larynx.

Intraoperative Details

Specific technical tips exist for each procedure; these have been elucidated earlier in this section (see Surgical therapy). Often, laryngoscopy performed before and during the procedure helps in preventing iatrogenic injury to the larynx and ensures the correct placement and extent of laryngeal incisions.

Postoperative Details

Postoperative care is critical in children. As stated earlier, any child requiring an ICU stay may have difficulties while receiving intubation and ventilation. Meticulous care from health care providers in the ICU may decrease the number of complications.

Follow-up

Children who undergo various laryngotracheal reconstruction procedures may have different follow-up care and courses, depending on the procedure performed. If a single-stage laryngotracheal reconstruction or ACS has been performed, bronchoscopy at extubation is not necessarily required; such decisions are left to the surgeon. However, 1-3 weeks after the procedure, bronchoscopy can be used to assess for any complications. Some authors examine the children after laryngotracheal reconstruction only if they have difficulty.

The author often performs laryngoscopy and bronchoscopy 1-2 weeks after extubation to evaluate the airway, since granulation tissue often forms in this period, as shown in the image below, and can lead to airway obstruction and scarring.

Granulation tissue (superior center portion of the Granulation tissue (superior center portion of the picture) that occurred at the graft site of a laryngotracheal reconstruction performed with an anterior graft.

A carbon dioxide laser can be used to remove and control the granulation tissue well, depicted in the images below. Certainly, any time the child has airway obstructive symptoms, bronchoscopy should be considered.

Intraoperative suspended view with a subglottoscop Intraoperative suspended view with a subglottoscope of the subglottis, showing the granulation tissue just prior to removal with cup forceps and laser.
Postexcision view of granulation tissue through th Postexcision view of granulation tissue through the subglottoscope.

In a child undergoing 2-stage laryngotracheal reconstruction with grafting and stent placement, the tracheotomy remains in place. The length of follow-up is determined by the duration of stent placement and the quality and quantity of symptoms after stent removal. For short-term stent placement (4-6 wk), follow up is 2 weeks after stent removal.

If this appears satisfactory, bronchoscopy should be performed at 4 weeks. In the interval, capping of the tracheotomy can be performed intermittently to evaluate for obstruction. If the bronchoscopy at 6 weeks is satisfactory, attempted decannulation can be considered. Prior to decannulation, the tracheotomy tube is usually downsized and plugged intermittently. If the child tolerates plugging, a sleep study can be performed, or the child can be decannulated and watched in the ICU or in a regular hospital room while monitored over night, depending on the individual case. Various methods to evaluate adequate airway prior to decannulation are available.

Walner and Cotton recommend repeat endoscopy at 1, 3, 6, 12, and 24 months after reconstructive surgery. This pattern allows long-term evaluation and detection of a recurring stenosis before it reaches a critical stage. Walner and Cotton also recommend capping and downsizing the tracheotomy in the hospital before decannulation.

For excellent patient education resources, see eMedicineHealth's patient education article Bronchoscopy.

Complications

Complications include the following:

Failure to correctly repair the stenosis occurs more often in severe stenosis than in moderate or mild stenosis. Zalzal and Choi examined 27 patients in whom laryngotracheal reconstruction failed and found that failure was related to the following:[21]

  • Inappropriate choice of graft

  • Inappropriate choice of stent

  • Inappropriate length of stent

  • Inappropriate duration of stent placement

  • Inadequate assessment and endoscopy

  • Poor postoperative follow-up

  • Anterior suprastomal collapse

  • Slipped Aboulker stent

  • Interactive progression of GERD

  • Keloid formation

  • Failure to repair all abnormalities noted at preoperative evaluation

Injury to recurrent laryngeal nerve has been reported in a single case of cricoid tracheal resection. Avoidance techniques are outlined in Surgical therapy.

The voice quality of patients with glottic stenosis and subglottic stenosis (SGS) is decreased and never restored to the preoperative state. However, once the subglottic stenosis (SGS) is repaired, subglottic pressure can be increased to increases volume and improve speech quality. See the images below.

Preoperative view of glottic stenosis and small gl Preoperative view of glottic stenosis and small glottic chink in a 2-year-old child.
Preoperative subglottic view of a 2-year-old patie Preoperative subglottic view of a 2-year-old patient with congenital and acquired vertical subglottic stenosis.
Postoperative view of the glottic larynx in a chil Postoperative view of the glottic larynx in a child who underwent anterior and posterior grafting for subglottic stenosis. Note the glottis is more open and in neutral position. The scarring of the right true vocal cord appears improved.
Postoperative close up view of the true vocal cord Postoperative close up view of the true vocal cords.
Postoperative subglottic view of patient who under Postoperative subglottic view of patient who underwent anterior and posterior grafting with successful decannulation showing open subglottis with some very mild damage to the anterior wall and the suprastomal area where the tracheostomy tube had been placed

If an anterior laryngeal fissure is required to repair the subglottic stenosis (SGS), voice quality can worsen, even if the anterior cartilage is displaced only mildly. Therefore, if possible, avoid dividing the anterior commissure.

Complications from laryngotracheal reconstructive surgery itself include pneumothorax, pneumomediastinum, neck wound infection, chest wound infection, and emphysema.

Complications during the postoperative ICU course can include those of laryngotracheal surgery itself in addition to atelectasis of lung segments, pneumonia, and neuromuscular weakness with the use of paralytic agents and steroids.

Outcome and Prognosis

The outcome of laryngotracheal reconstruction depends on its grade and the procedure performed. Most authors report success rates of 80-90% when the patient has undergone successful preoperative evaluation and when the appropriate surgery has been performed, as shown in the images below.

Postoperative subglottic view of patient who under Postoperative subglottic view of patient who underwent anterior and posterior grafting with successful decannulation showing open subglottis with some very mild damage to the anterior wall and the suprastomal area where the tracheostomy tube had been placed
Subglottic view of an anterior graft, placed for a Subglottic view of an anterior graft, placed for anterior subglottic stenosis. The white areas to the left and right are the true vocal cords. The graft is seen at the superior and mid area.

The presence of acute or chronic respiratory illness, GER, or a reactive larynx may decrease the success rate. Choi and Zalzal showed that age can affect success rates; scars are more likely to recur in children younger than 2 years than in others.[23]

Zalzal noted that, in any child with voice abnormalities before surgery, those abnormalities persisted after surgery. Subglottic pressure is required to produce a strong voice. If the narrowed subglottic airway is expanded, subglottic airflow and pressure increase, and the voice usually is stronger. See the images below.

Preoperative view of glottic stenosis and small gl Preoperative view of glottic stenosis and small glottic chink in a 2-year-old child.
Preoperative subglottic view of a 2-year-old patie Preoperative subglottic view of a 2-year-old patient with congenital and acquired vertical subglottic stenosis.
Postoperative view of the glottic larynx in a chil Postoperative view of the glottic larynx in a child who underwent anterior and posterior grafting for subglottic stenosis. Note the glottis is more open and in neutral position. The scarring of the right true vocal cord appears improved.
Postoperative close up view of the true vocal cord Postoperative close up view of the true vocal cords.
Postoperative subglottic view of patient who under Postoperative subglottic view of patient who underwent anterior and posterior grafting with successful decannulation showing open subglottis with some very mild damage to the anterior wall and the suprastomal area where the tracheostomy tube had been placed

Voice therapy may help relieve nonsevere glottic stenosis over time.

The voice of a patient with subglottic stenosis (SGS), especially those who require reconstruction, may never return to it preoperative state because the following are possible: (1) glottic stenosis, (2) imperfect closure of a laryngofissure through the anterior commissure, and (3) potential vocal cord weakness or tension caused by other laryngeal pathologic conditions. Since reconstructive techniques have improved over the last 20 years, the focus of attention in patients with subglottic stenosis (SGS) who require reconstruction has switched from decannulation to decannulation with improved voice outcome.

Future and Controversies

Controversies remain concerning the surgical techniques for mild-to-moderate subglottic stenosis (SGS). Options include endoscopic laser removal and dilation for mild subglottic stenosis (SGS) versus an open procedure. Most authors believe that, in children, scar excision with laser and dilation usually is unsuccessful in mature and severe subglottic stenosis (SGS). Many authors have reported the use of topical mitomycin applied to the area of laser excision of subglottic scar to improve the patency rate, as mentioned in the Surgical section. Mitomycin is proposed to help decrease scar formation by decreasing the cell division through its action on the microtubules in anaphase of mitosis. Despite the feeling that this antiproliferative agent is helpful, no consensus exists on its use.

The type of cartilage used for augmentation and reconstruction can be controversial as well. Some authorities believe that thinner cartilage (eg, auricular cartilage, thyroid ala) is satisfactory reconstructive material in certain situations. Most authorities recognize that costal cartilage provides the most support and that, in severe stenosis, weaker cartilage may be inadequate. The choice of cartilage often depends on the degree and location of the stenosis and on the postoperative care. Most airway reconstructive surgeons believe that posterior subglottic stenosis (SGS) requires lumen augmentation with firm cartilage. The selection of the anterior cartilage is not as critical, especially when stents are used after the procedure. In this setting, various authors have reported good success with superior strips of thyroid cartilage and auricular cartilage.

As with most diseases requiring surgical treatment, evaluations based on genetic predisposition and medical therapies to prevent the disease process that requires surgery are being evaluated. Novel ideas of expanding the airway, including the use of expandable and bioabsorbable airway stents, are being investigated. The role of growth factors and techniques to prevent wound healing are being evaluated as well. Unquestionably, any technique, device, or therapy that decreases the need for surgical intervention or donor cartilage decreases morbidity.