No medical therapy for mature subglottic stenosis (SGS) is known. If a granular or immature SGS is noted, treatment of the inflammatory process with oral or inhaled steroids sometimes can decrease the severity of disease.
Perform surgical repair of SGS if the child has SGS and is symptomatic. Typically, children with grade I (see 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.
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 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 SGS has a cold, bronchitis, or both but does not have 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 SGS.
Occasionally, older children have exercised-induced airway obstruction. At evaluation, these children may have grade I or grade II SGS. Expansion of the airway with cartilage augmentation may allow them to lead a healthy and active lifestyle.
Children with grade III (see the images below) or grade IV SGS need surgical management.
Findings from animal studies showed that treatment with antibiotics and steroids can help improve an immature or granular SGS (see the image below); however, the optimal treatment duration is unknown. Evaluate each case on an individual basis. Once SGS is mature, medical therapy is almost always unsuccessful. However, suspected gastroesophageal reflux (GER) must receive aggressive medical treatment preoperatively and postoperatively for optimal surgical results.
No special diet is necessary in the treatment of pediatric SGS. The need for restriction of activity is evaluated on an individual basis.
For mild or granular SGS, investigators have reported success with serial endoscopic dilation, with or without steroid injections.  Endoscopic balloon dilation has only limited applicability to severe SGS. 
Healy popularized the use of the carbon dioxide laser as an option for soft circumferential SGS. This procedure involves incisions made in four quadrants, followed by dilation. The technique is best used in conjunction with steroids when an immature or granular SGS is present. Normally, use of a laser causes recurrence of the scar in a mature stenosis; however, in unusual types of mature SGS (eg, spiraling SGS), improvement may be accomplished with a few serial carbon dioxide laser excisions (see the images below).
Although controversial (no good placebo-controlled studies have been performed to back up results), mitomycin-c has been reportedly used after carbon dioxide lasering of a mature SGS with presumed improved results over lasering alone, with or without the use of oral steroids. The author has used topical mitomycin-c after lysing an immature stenotic web, with results seemingly superior to those achieved with lysing and oral steroids alone.
The approach to open reconstruction of SGS should be based on the location and degree of scarring. Reconstruction often may be unnecessary for SGS classified as grades I and II on the Myers-Cotton scale (ie, ≤70% obstruction of the subglottic airway). When surgery is necessary on the basis of symptom severity, perform an open reconstruction in mature circumferential SGS. The surgical technique depends on adjacent areas of scarring and on the location and appearance of SGS. For severe 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.
For SGS classified as grade II (50-70% stenosis), surgical reconstruction depends on many factors, including symptoms, environment, and associated medical conditions.
Various procedures for treating SGS include the following:
Anterior cricoid split (ACS)
Single-stage procedure involving anterior cartilaginous grafting with costal, thyroid, or auricular cartilage
Multistage 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
Anterior cricoid split
In 1980, Cotton and Seid described the use of ACS to avoid tracheotomy in neonates with SGS, good pulmonary and cardiac function, and airway obstructive symptoms after extubation.  ACS allows decompression of the edematous submucosal glands of the subglottis and thus expansion of the airway. 
Criteria developed to identify children who are likely to benefit from ACS include the following:
Patient weight of more than 1500 g
Failure to extubate in identified SGS
Oxygen requirement of less than 30%
No active respiratory infection
Good pulmonary and cardiac function
Transport the already intubated child from the intensive care unit (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 (see the image below). Place polypropylene 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; doing so can lead to pressure on the mucosa and persistent SGS.
Loosely close the skin over the wound, and place a rubber band drain. Mark the 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 operating room (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 H2O, 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 ACS are unusual and include pneumothorax, pneumomediastinum, subcutaneous emphysema, wound infection, and persistent SGS.
The images below were obtained in a 4-month-old infant born 3 months premature who required intubation and ventilation for 3 months.
She had a grade III SGS and underwent ACS with intubation and ventilation for 1 week in the ICU. The image below shows the subglottis 1 week after extubation.
The size of the larynx was determined with an endotracheal tube, and subsequent dilation of the soft mild restenosis is depicted in the images below.
The child received oral steroids for 5 days and underwent follow-up bronchoscopy 2 weeks later (see the image below).
Single-stage laryngotracheoplasty with cartilage expansion
In 1991, Seid et al reported the use of single-stage LTP.  Their approach to the airway resembles ACS; however, instead of leaving the area anterior to the fibrosis, they placed a piece of costal cartilage. The procedure was performed in 13 patients with 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 SGS was a contraindication to single-stage LTP. Two patients had grade III 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 H2O.
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 because wandering atelectasis can be present in a patient who is ventilator-dependent for as long 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 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 SGS.
In 1995, Rothschild et al reviewed the effectiveness and complications of single-stage LTP in 104 patients from the Children's Hospital of Cincinnati.  Repair was successful in 86-92%, depending on the year of correction. The authors did not use paralysis during the 5-day to 10-day period of endotracheal tube placement; they used sedation with chlorohydrate and benzodiazepines instead. In fact, if patients could tolerate nasotracheal intubation without much difficulty, they were allowed to engage in their usual activities (eg, 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 days) in 37 children. Twenty-three children, however, had a posterior costal cartilage graft, which normally necessitates 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 et al also described a single-stage LTP in which auricular cartilage is used for reconstruction when an anterior 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. The authors 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 SGS is present, use of cartilage that is rigid enough to maintain the splay of the cricoid cartilage is usually 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 (see the images below). 
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 (see the image below). 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.
The use of a superior section of the thyroid cartilage, as well as the septal cartilage, as grafting material has been reported. 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 the success rate of that procedure, which has traditionally 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 SGS in infants younger than 6 months in whom extubation in the ICU failed.  They reproted improved results 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.
However, Zalzal and Choi pointed out that when the results of laryngotracheal reconstruction were evaluated in 48 patients aged 4 years or younger, the success was lower in children younger than 25 months than in those aged 2-4 years.  (Note that the patients younger than 2 years had SGS that was less severe than that of the older patients.) Zalzal and Choi still recommended laryngotracheal reconstruction in younger patients, on the grounds the procedure may aid the child's speech and language development and help prevent tracheotomy complications.
Anterior and posterior grafting
For severe SGS (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.  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 graft 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 (see image below), at which time the sutures can be tied. Seid described using fibrin glue in an animal study to keep a posterior graft in place, avoiding the arduous task of suturing it in.
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, in that 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 (see the first, second, and third images below) or Montgomery T tube (natively, as in the fourth image below, or cut to fit and used like an Aboulker stent, which are no longer commercially available) is used. 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 (see the images below) or a Montgomery T tube. Complications of short-term (4-6 weeks) stent placement, 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" (ie, Cotton's 20 years of 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 SGS (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 the open wound is simultaneously viewed directly, 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 dissect 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. Dissect the trachea until four or five rings are mobilized to aid in decreasing tension on the suture line. In addition, place two or three additional tension-releasing sutures on the thyroid ala and the upper tracheal rings to help release tension from the suture line. Place polypropylene 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 et al reported good results with decreased morbidity with T tubes in children. [33, 34]
Failure to repair the stenosis correctly 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  :
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 gastroesophageal reflux disease (GERD)
Failure to repair all abnormalities noted at preoperative evaluation
Injury to the recurrent laryngeal nerve has been reported in a single case of cricoid tracheal resection. Avoidance techniques are outlined in Surgical care.
The voice quality of patients with glottic stenosis and SGS is decreased and is never restored to its preoperative state. However, once the SGS is repaired, subglottic pressure can be increased to increase volume and improve speech quality (see the images below). If an anterior laryngeal fissure is required to repair the 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, as well as atelectasis of lung segments, pneumonia, and neuromuscular weakness with the use of paralytic agents and steroids.
When a child is intubated for any reason, check for an air leak. When possible, the pressure should be less than 20 cm H2O in order to prevent pressure necrosis and SGS. Use appropriately sized endotracheal tubes when intubating a child for any reason. Treat intubated patients with antireflux medications.
Consult a pediatric gastroenterologist if GER is suspected or present.
Consult a pediatric pulmonologist if chronic lung disease or an oxygen requirement is present.
Occasionally, inhaled steroids are used to help prevent restenosis following reconstruction. Also, GER may have to be treated if it is suspected or proved, and treatment for "allergic" gastritis may be warranted.
Children who undergo various laryngotracheal reconstruction procedures may have different follow-up care and courses, depending on the procedure performed.
If a single-stage LTP 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 because granulation tissue often forms in this period (see the image below) and can lead to airway obstruction and scarring.
A carbon dioxide laser can be used to remove and control the granulation tissue well (see the images below). Certainly, whenever the child has airway obstructive symptoms, bronchoscopy should be considered.
In a child undergoing two-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 weeks), 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. Before decannulation, the tracheotomy tube usually is 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 being monitored overnight, 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.
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