Kishore Sandu and Philippe Monnier
Introduction
The management of laryngotracheal stenosis (LTS) remains a challenging problem for the surgeon, especially in the pediatric age group. The complexity of the various preoperative situations implies that no single treatment modality can solve the problem. One has to take into consideration the type of the stenosis (congenital or acquired), its location in the airway (supraglottic, glottic, subglottic or combined), its degree of obstruction and length in the craniocaudal axis, and, finally, its association with vocal cord fixation or neurogenic paralysis. Furthermore, the presence of tracheal damage (stenosis or localized malacia) related to the tracheostoma or to the tracheostomy cannula can further complicate the surgical management. According to the nature and severity of the condition, a variety of treatments exists. They comprise endoscopic laser sessions with or without dilatation or stenting; laryngotracheal reconstruction (LTR) with anterior, posterior, or combined costal cartilage grafts; partial cricotracheal resection (PCTR) for the most severe grades of stenosis; and extended PCTR for combined glotto-subglottic stenosis.
Needless to say, a thorough preoperative endoscopic assessment is a prerequisite to selection of the best surgical option for a given condition.
In the pediatric age group, the most common reason for subglottic stenosis (SGS) is prolonged intubation. In newborns, however, congenital SGS represents the third most common laryngeal anomaly after laryngomalacia and bilateral vocal fold paralysis. According to Holinger, congenital SGS is classified into cartilaginous and soft tissue stenoses. The cartilaginous type results from a failure of complete recanalization of the laryngeal lumen after the eighth week of gestation. The cricoid may be normal in shape but too small for the infant’s size or it may have different abnormalities such as general thickening of the cricoid ring, a large anterior or posterior lamina, or an elliptical shape. Sometimes, a trapped first tracheal ring is responsible for the small size of the subglottis.
In approximately 50% of cases, a congenital SGS is associated with mediastinal malformations, such as cardiovascular, tracheobronchial, or esophageal anomalies. For the surgeon and anesthesiologist, this implies that any mediastinal malformation warrants bronchoesophagoscopy before treatment to rule out a minor asymptomatic congenital SGS that can evolve into a severe cicatricial SGS after a short-term intubation only.
Injuries leading to acquired SGS in infants and children are more likely to occur after traumatic intubation for resuscitation, after intubation for severe cranial injuries, when laryngoscopy is difficult because of anatomic problems, or when a mild congenital SGS has been overlooked. The evolution of acute lesions of intubation into cicatricial sequelae of the glottis and subglottis were clearly described in children by Benjamin in 1993.
In the pediatric community, the Myer–Cotton grading system is routinely used. This system classifies SGS into four grades: Grade I corresponds to less than 50%, Grade II to 51% to 70%, and Grade III to 71% to 99% airway obstruction, respectively. In Grade IV SGS, no detectable lumen is identifiable.
INDICATIONS/CONTRAINDICATIONS
Indications
Primary Endoscopic Treatment
Cautious carbon dioxide (CO2) laser incisions combined with dilatation may be effective in treating thin, web-like cicatricial stenoses of the subglottis, but extensive laser resection is liable to make an acquired stenosis worse.
The indications described by Simpson et al. in 1982 are still valuable today as a basis for the endoscopic treatment of LTS. The CO2 laser should be set to superpulse or ultrapulse mode, and the laser beam should be directed to the target with a microspot manipulator (250 μ spot size at 400-mm focal distance) to minimize heat diffusion into the surrounding tissue. Radial incisions in the stenosis are made using Shapsay’s technique, and gentle dilatation is done with tapered bougies or with angioplasty balloons. Next, a cotton swab soaked in a solution of 1 to 2 mg per mL Mitomycin C may be applied topically to the subglottis for 2 minutes. Repeated Mitomycin C applications should probably be avoided because of the uncertainty regarding possible late adverse effects.
Finally, if primary endoscopic treatment (CO2 laser/dilatation/stenting) leads to a recurrence of the stenosis to its initial grade, then any further endoscopic treatment is strictly contraindicated. Open surgery should be considered instead.
Laryngotracheal Reconstruction with Cartilage Expansion (LTR)
This surgery is almost exclusively reserved for milder grades of pediatric SGS or for combined glotto-subglottic stenoses.
LTR with an anterior graft alone is used as a single-stage operation for the resolution of Grade II SGS. Mild Grade III stenosis is likely to need an anterior graft with posterior cricoid split supported by an endoluminal stent, and severe Grade III stenosis requires both anterior and posterior grafts with stenting. However, over the last decades, PCTR has been shown to be superior to LTR for the treatment of pediatric Grades III and IV SGSs.
In the case of congenital stenosis, the LTR may be combined with submucosal resection of cartilage to increase the size of a thickened anterior lamina of the cricoid ring.
PGS in children presents particular difficulties. A posterior cartilage graft is needed, but overexpansion of the posterior commissure should be avoided as it will impair voice quality and induce potential aspiration. Stenting is essential until complete healing of the glottis and subglottis has been obtained.
Partial Cricotracheal Resection (PCTR)
In infants and children, PCTR is the procedure of choice for the treatment of severe (>70% luminal obstruction) SGS of congenital or acquired etiology. PCTR is performed as a single-stage operation (with concomitant resection of the tracheostoma during the surgery) when the stenosis is purely subglottic, and the child is otherwise healthy. The only exception to this rule is a very distal location of the tracheostoma (fifth or sixth tracheal ring), with normal and steady tracheal rings available for the anastomosis between the SGS and the upper margin of the tracheostoma. The latter is then closed in a second stage.
In children with multiple congenital anomalies or with impaired neurologic or cardiopulmonary function, a double-stage PCTR (with postoperative maintenance of the tracheostoma) is preferable.
Indications
• Primary endoscopic treatment for thin, web-like Grade I, II, and mild Grade III SGS
• Single-stage LTR for Grade II and some mild Grade III SGS
• Double-stage LTR for any Grade of SGS in infants and children with severe comorbidities
• Single-stage PCTR for Grade III and IV SGS in an otherwise healthy child
• Double-stage PCTR for Grade III or IV SGS in children with compromised neurologic or cardiopulmonary functions and/or multiple congenital anomalies
• Double-stage extended PCTR with stenting for Grades III and IV SGS associated with cicatricial or congenital glottic involvement
Extended PCTR
In the pediatric age group when an SGS is combined with glottic involvement such as posterior glottic stenosis (PGS), cicatricial fusion of the vocal cords, or distortion of the laryngeal framework resulting from failed LTRs, then PCTR is supplemented with a posterior cricoid split and costal cartilage graft that need stenting with an LT-Mold for about 3 weeks until complete healing of the subglottic area is obtained. The tracheostoma is then closed in a second stage. The alternative to this treatment is an LTR with anterior and posterior costal cartilage grafts with stenting, albeit with less chance of success, especially in severe stenosis grades.
Stenting
Laryngeal stents are mainly used to keep the airway expanded after surgical reconstructions involving the glottis (LTR with costal cartilage grafts or extended PCTR). They provide support for cartilage grafts, allow approximation and immobilization of mucosal grafts to the recipient site and maintain the lumen in a reconstructed area that lacks adequate support. Unfortunately, laryngeal stents can also act as foreign bodies in a reconstructed airway and induce mucosal injuries, ulcerations, granulation tissue formation, and subsequent restenosis if their anatomical conformity to the inner laryngeal contours is not perfect, or if their consistency is too hard. Several laryngeal stents are currently available on the market, but none of them truly meets the requirements for safe use without potential damage to the reconstructed airway.
To overcome this problem, the LT-Mold has been designed for the temporary stenting of the airway after surgical treatment of cicatricial stenoses of the larynx. Its design was created after molding cadaver larynges and increasing the interarytenoid distance to obtain the intralaryngeal contours of a fully abducted larynx. The prosthesis exists in 10 different sizes (from 6 to 15 mm in outer diameter), and four different lengths per size to accommodate the position of the tracheostoma with respect to the vocal folds.
Contraindications
Strict contraindications to an airway resection/reconstruction are rare. They are usually related to severe systemic comorbidities that cannot be corrected despite adequate medical or surgical treatment. These comorbidities comprise cardiopulmonary diseases with O2 dependency, severe neurologic impairment or mental disability associated with pharyngolaryngeal discoordination and chronic aspiration during feeding, and finally severe maxillofacial abnormalities or multiple congenital anomalies.
Local factors affecting the airway, such as severe reflux laryngitis, a highly reactive larynx, an immature LTS, airway colonization with resistant bacteria, severe gastroesophageal reflux or eosinophilic esophagitis, and extralaryngeal sites of airway obstruction are all amenable to medical and/or surgical improvement prior to airway resection or reconstruction.
Gastroesophageal reflux should be treated with proton pump inhibitors or a fundoplication when deemed necessary; eosinophilic esophagitis confirmed by biopsy warrants full medical treatment prescribed by the gastroenterologist and the allergologist; airway colonization with MRSA, Pseudomonas aeruginosa or extended spectrum beta-lactamase (ESBL) requires a 5-day preoperative antibiotic prophylaxis based on bacteriologic cultures and sensitivities; a highly reactive larynx not responsive to antireflux treatment deserves a 3-month trial of Azythromycin (10 mg per kg bodyweight thrice weekly) as an immunomodulator to diminish the idiopathic chronic inflammatory reaction of the larynx; finally, an immature LTS only requires a waiting period before surgery is undertaken.
Most secondary dynamic airway stenoses usually benefit from surgical treatment: For instance, adenotonsillectomy for naso- or oropharyngeal obstruction; supraglottoplasty for laryngomalacia; maxillofacial procedures for craniofacial anomalies; and tracheomediastinal procedures for localized malacia related to the tracheostomy site, tracheoesophageal fistulae or vascular compressions of the airway, to mention but a few.
In summary, all efforts should be made to optimize the patient’s local and general conditions prior to any surgical intervention.
PREOPERATIVE PLANNING
A thorough endoscopic evaluation usually provides all of the information needed for careful planning of the surgery.
If precise description and measurement of the stenosis are obtained from the endoscopy, then radiographs add little to the preoperative workup. However, CT-scan with three-dimensional reconstructions is useful in documenting the length of the segment to be resected in case of complete airway obstruction. When a malformation of the mediastinum is suspected, computed tomography or magnetic resonance imaging are the examinations of choice.
Endoscopic Evaluation
Considering the potential dramatic consequences of a failed PCTR or LTR, careful attention should be given to the preoperative endoscopic workup. It should comprise a transnasal flexible laryngoscopy (TNFL) in spontaneous respiration, a direct laryngotracheoscopy in general anesthesia with suspension microlaryngoscopy (if needed), and a bronchoesophagoscopy.
Transnasal Flexible Laryngoscopy (TNFL)
In neonates and cooperative children, this investigation is done in the awake patient without sedation. This is the most effective way of assessing vocal fold mobility. In noncooperative children, TNFL under deep sevoflurane anesthesia with mask ventilation and spontaneous respiration is the preferred method. This examination not only gives information on the mobility of the vocal cords but also on the dynamic patency of the nose, the choanae, the nasopharynx, and the oropharynx. It must be pointed out here that anesthetic drugs can modify the interpretation of dynamic airway functions, hence the role of an experienced pediatric anesthesiologist to titrate the optimal depth of sedation for assessing vocal fold mobility. In the tracheostomized child, the cannula should be removed and the tracheostomy blocked temporarily to allow normal inspiration and exhalation, thereby allowing precise dynamic identification of intra- and extrathoracic malacic tracheal segments. If there is any doubt about the mobility of the vocal cords during transnasal fiberoptic laryngoscopy, then additional investigation in suspension microlaryngoscopy is mandatory.
Direct Laryngotracheoscopy and Suspension Microlaryngoscopy
Location, extent, and degree of stenosis are assessed using a bare magnifying telescope and the intubation laryngoscope while the patient is under general anesthesia and fully relaxed. The exact location of the stenosis with respect to the vocal folds, the tracheostoma, and the carina is given in millimeters. The degree of the stenosis is measured by passing telescopes, endotracheal tubes, or bougies of different given sizes through the stricture. In the pediatric community, the Myer–Cotton airway grading system is routinely used. This system classifies SGS into four grades and helps predict the rate of success after LTR because the less severe grades (I and II) have a far better outcome than do the severe grades (III and IV), which correspond to a subtotal or total obstruction. For PCTR, this grading system is not useful as a predictor of success or failure, because the stenotic segment is fully resected.
Differentiating vocal fold immobility due to a neurogenic cause from an interarytenoid fibrous adhesion is done by carefully inspecting the posterior commissure of the larynx, using a 30-degree, angled telescope and by direct palpation of the arytenoid cartilages during suspension microlaryngoscopy. The systematic use of Lindholm’s self-retaining vocal cord retractor (Storz no. 8654B) helps differentiate bilateral neurogenic vocal fold paralysis from PGS. A fixed arytenoid raises the suspicion of fibrous ankylosis of the joint, but in the most difficult cases, this diagnosis is only safely made during open surgery.
The endoscopy report should also mention the presence of any localized tracheomalacia as well as a possible infection of the airway. A bacteriologic aspirate of the trachea is routinely taken.
Preoperative Planning
Endoscopy
• Perform transnasal fibroscopy during spontaneous respiration to assess vocal fold mobility and potential extralaryngeal sites of obstruction (naso-oropharynx, tracheostoma, intrathoracic trachea)
• Use rigid direct laryngotracheoscopy with a bare 0-degree telescope to assess location, extent, and size of SGS and tracheostoma
• Implement suspended microlaryngoscopy in cases of vocal fold immobility to differentiate neurogenic paralysis from cicatricial fixation of the vocal folds
• Obtain a bacteriologic aspirate of the trachea prior to any surgical treatment
• Do workup studies for gastroesophageal reflux and eosinophilic esophagitis
• Add bronchoesophagoscopy to rule out associated mediastinal anomalies in all congenital SGSs
Patient’s General Condition
• Obtain full medical history on the potential etiology of SGS, including the cause for long-term intubation
• Assess cardiopulmonary condition especially in children with a history of prematurity or congenital anomalies
• Obtain full evaluation of multiple congenital anomalies including a neurologic examination
• Perform swallowing function tests when medical history is positive
• Perform evaluation for gastroesophageal reflux to determine need for further studies or treatment
Bronchoesophagoscopy
In infants and children, this additional examination is mandatory in all cases of congenital SGS to rule out an associated mediastinal malformation (e.g., tracheoesophageal fistula, tracheobronchial anomalies, and extrinsic vascular compression of the airway), gastroesophageal reflux, or eosinophilic esophagitis.
SURGERY
Primary Endoscopic Treatment
These endoscopic techniques belong to the otolaryngologist’s armamentarium, but thoracic and pediatric surgeons should be cognizant of their therapeutic potential for addressing the challenging problem of cicatricial involvement of the glottis, such as PGS, vocal fold synechia, and cricoarytenoid joint fixation that are often associated with SGSs in the pediatric age group.
Strict adherence to proper indications, as previously described in this chapter, is a prerequisite to any endoscopic treatment.
The management of PGS requires expertise in the selection of the appropriate candidate for the right type of treatment. Interarytenoid adhesion with a residual posterior opening is usually not associated with cricoarytenoid (CA) joint fixation. Division of the scar with the CO2 laser is thus the first appropriate choice of treatment with a potentially high success rate. True PGS without CA joint fixation should first be treated endoscopically with the CO2 laser and adjuvant topical application of Mitomycin C. Five to seven days of postoperative intubation with a soft blue-line Portex tube help achieve a satisfactory result. The abductive force of both posterior CA muscles will prevent recurrence of the PGS, at least to some degree. In tracheostomized patients, 2 to 3 weeks of stenting with an LT-Mold ensures reepithelialization of the posterior commissure in the abductive position of the vocal folds, thus recreating an adequate airway for breathing. In cases of true fixation of the CA joints, a laser arytenoidectomy, a posterior cordotomy or a posterior costal cartilage graft should be envisaged. When PGS is combined with a SGS, open surgery is mandatory in most cases (see extended PCTR).
Laryngotracheal Reconstruction with Cartilage Expansion (LTR)
This operation is performed through a small collar incision placed at the superior edge of the tracheostoma. The strap muscles are separated from the midline to expose the anterior portion of the larynx and upper trachea.
For a Grade I or II SGS without glottic involvement, a simple LTR with anterior cartilage graft is usually sufficient. The vertical incision typically extends through the lower third of the thyroid cartilage, the thyrocricoid membrane, the cricoid, and the first two tracheal rings. The costal cartilage harvested from the fifth, sixth, or seventh rib is boat-shaped and placed with the perichondrium intraluminally, serving as a lattice for reepithelialization. Lateral flanges of cartilage to the inset portion of the graft are secured to the thyroid, cricoid, and tracheal rings with 4-0 Vicryl sutures, thus preventing prolapse of the graft into the airway (Fig. 37.1).
For an isolated PGS (without SGS), the anterior median incision is made as mentioned previously to gain access to the cricoid plate. The posterior cricoid split is made strictly in the midline, and the divided cricoid laminae are expanded laterally with a Cryle forceps. The scarred interarytenoid muscle should always be completely sectioned. The costal cartilage is shaped in a rectangular fashion with preservation of the posterolateral flanges. It is then snapped into position with the posterior flanges resting behind the divided cricoid laminae to avoid graft displacement.
The treatment of a Grade III SGS requires both anterior and posterior grafts with stenting. For the placement of the posterior cartilage graft, it is necessary to extend the anterior thyrotracheal incision into a full laryngofissure. The cricoid plate is then divided in the midline and when present, the interarytenoid scarring is accurately resected. A rectangular-shaped costal cartilage graft is then inserted between the two parts of the posterior cricoid plate with the perichondrium facing the lumen. The graft must fit flush between the divided posterior cricoid laminae, and it is sutured into place with 4-0 Vicryl sutures (Fig. 37.2). An LT-Mold of appropriate diameter is placed at that stage and securely fixed with 3-0 Prolene sutures placed horizontally through the tracheal wall. Depending on the individual situation, the vertical incision of the trachea is closed over the stent with or without additional anterior costal cartilage grafting, as described earlier.
Figure 37.1 A: Double-stage laryngotracheal reconstruction with anterior costal cartilage graft: The costal cartilage graft is sewn into position, with the perichondrium facing the lumen. Large cartilage flanges prevent prolapse of the costal cartilage graft into the airway. B: Correct placement of stitches through the boat-shaped anterior costal cartilage graft for laryngotracheal reconstruction: The stitch, inserted through the dorsal portion of the cartilage, must emerge exactly at the edge of the perichondrium on the boat-shaped portion of the costal cartilage graft.
Figure 37.2 Full laryngotracheofissure for subglottic stenosis combined with glottic involvement. A: The incision is first made just above the thyroid notch to provide complete visualization of the glottis during the midline laryngofissure. The posterior cricoid split must be placed precisely in the midline. The cuts should be perpendicular to the plane of the cricoid plate. B: Results after posterior costal cartilage grafting: The interarytenoid and subglottic spaces have been enlarged. C: Diagrammatic representation of suturing the posterior graft into position: The needle must be inserted through the perichondrium and emerge exactly at the angle created by the lateral flanges of the cartilage. Four stitches are sufficient to stabilize the graft.
Single-stage Versus Double-stage LTR
The decision is based on the severity of the initial stenosis, the type of LTR that was performed (anterior graft only vs. anterior and posterior costal cartilage grafts) and the patient’s medical condition. Poor cardiopulmonary function and neurologic impairment are contraindications to a single-stage LTR even for a Grade II or mild Grade III SGS. Depending on the stability of the reconstructed airway, an LT-Mold stent is secured in place and left in the airway for a period of 3 weeks to 6 months.
Partial Cricotracheal Resection for Subglottic Stenosis
The procedure is performed with the neck fully extended. Especially in small children, it is advisable to use magnifying glasses because of the small size of the structures being manipulated. This also aids in meticulous placement of the anastomotic sutures.
1. A collar incision is usually made at the level of the second tracheal ring. In tracheotomized patients, a horizontal crescent-shape excision of the skin is made around the stoma.
2. The subplatysmal skin flap is elevated, and the strap muscles are separated from the midline to provide exposure from the hyoid bone to the suprasternal notch. The isthmus of the thyroid gland is transected in the midline.
3. The trachea is dissected anteriorly and laterally without identification of the recurrent laryngeal nerves (RLNs) by staying in close contact with the underlying cartilaginous rings. The vascular supply coming laterally from the tracheoesophageal grooves should always be carefully preserved, especially in extensive mobilization of the distal trachea.
4. At the level of the cricoid arch, the cricothyroid muscles are sharply dissected off the underlying cartilage until the cricothyroid joint is identified bilaterally.
5. After having placed stay sutures to the distal normal tracheal wall, the inferior resection line is made first at the lower end of the stenosis or at the level of the tracheostoma if the latter is to be resected during the same surgical procedure.
6. Unnecessary extensive separation of the trachea from the esophagus should be avoided to preserve vascularity of the posterior tracheal mucosa. The advancement of the distal tracheal stump upward is achieved by freeing the cartilaginous rings from the mediastinal structures only anteriorly and laterally. Because of its elasticity, the esophagus shortens spontaneously without anterior bulging.
7. The superior incision is started at the inferior margin of the thyroid cartilage in front and is passed laterally just anterior to the cricothyroid joints, which results in the complete resection of the anterior cricoid arch while avoiding injury to the RLNs that run posteriorly to the cricothyroid joints. In the subglottis, the uppermost incision of the posterior mucosa is made just below the CA joints, and the submucosal fibrosis that constitutes the posterior aspect of the SGS is fully resected, thus exposing the cricoid plate completely.
8. In children and infants, the difference in diameter between the subglottic space and the tracheal stump is more pronounced than in adults, hence, the first normal tracheal ring used for the anastomosis must be adapted to the size of the subglottic lumen. Any attempt at reducing the caliber of the trachea should be avoided. Instead, one should enlarge the subglottic lumen as much as possible without compromising voice quality. This approach is best achieved by widening the cricoid plate posteriorly and laterally with a diamond burr and performing an inferior midline thyrotomy up to the level of the anterior commissure of the larynx without transecting it. In this way, the subglottic lumen is enlarged considerably while the anterior commissure is kept intact, thus preserving a good voice. The triangular defect at the anterior wall is filled in with a mucosa-lined cartilaginous wedge that is obtained from the first normal tracheal ring below the resected stricture. The denuded cricoid plate is covered with the membranous trachea after its upward mobilization.
Depending on the patient’s age, 4-0/5-0 Vicryl sutures are used for the thyrotracheal anastomosis. The first stitch is passed through the posterolateral aspect of the first normal tracheal ring and through the cricoid plate laterally. It should emerge in a subperichondrial plane from the outer surface of the cricoid plate to avoid any damage to the RLNs. This stitch is important and should be placed as meticulously as possible to bring the mucosa of the subglottis in close contact with the mucosa of the trachea (Fig. 37.3). Posterior anastomosis between the tracheal and posterior glottic mucosa is done using 5-0 Vicryl or PDS, either in a continuous running stitch or intermittently with the knots tied inside the lumen. The anterior and lateral thyrotracheal anastomosis is completed by placing the sutures between the tracheal rings and the thyroid cartilage anteriorly, with the knots tied on the outside. A tension-releasing suture is also placed between the third or fourth tracheal ring laterally and the inferior border of the cricoid plate (Fig. 37.4).
Anastomotic Tension Release Procedures
Various techniques of tracheal and supralaryngeal release may be used to diminish the tension on the suture line, depending on the length of the tracheal segment to be resected and on the individual anatomy. Usually, the advancement of the distal tracheal stump upward is much easier in children than in adults. If necessary, a laryngeal release suffices; hilar and pericardial mobilizations, sometimes used in adults, should remain as an exception in children.
Figure 37.3 Thyrotracheal anastomosis after partial cricotracheal resection: The posterolateral stitches are actually cricotracheal stitches. They are first passed through the posterolateral subglottic mucosa, and then through the cricoid plate where they must emerge in a subperichondrial plane on the outer surface to avoid injury to the recurrent laryngeal nerves. As these two stitches dictate the quality of mucosal approximation for the posterior anastomosis, they are essential to avoid recurrent stenosis.
At the end of the procedure, the neck is maintained in a flexed position. Sutures placed from the chin to the chest are never used in our institution to limit the extension of the neck during the postoperative period although this measure has been recommended for children by certain authors.
Single-stage Versus Double-stage Partial Cricotracheal Resection
If a patient is fit for single-stage surgery, then two options usually exist, depending on the location of the tracheostoma. Either the stoma is close to the resection site and can be concomitantly excised during the primary procedure, or the stoma is away from the resection site with at least three to four vascularized tracheal rings between the anastomosis and the stoma, in which case the distal stoma is maintained instead of risking a long resection and its potential anastomotic dehiscence.
A single-stage PCTR with perioperative resection of the tracheostoma is chosen if no more than five tracheal rings must be resected with the SGS. The absence of a postoperative tracheostoma is favorable for healing of the anastomosis, but longer tracheal resections carry greater risk of anastomotic dehiscence.
Figure 37.4 Completion of thyrotracheal anastomosis: Note the alternate position of the stitches through the first and second tracheal rings so as to distribute the anastomotic tension onto different levels. An additional tension-releasing suture is placed between the posterolateral aspect of the cricoid plate and the trachea (displayed in turquoise). Staying in a subperichondrial plane at the cricoid level is essential to avoid injury to the recurrent laryngeal nerves. The triangular wedge of pedicled trachea is trimmed to the size of the corresponding subcommissural defect and sutured in place with two or three 5-0 Vicryl sutures.
Extended Partial Cricotracheal Resection (E-PCTR)
PCTR with certain surgical modifications has proven to be efficient for treating a combination of SGS and glottic pathologies (PGS; cicatricial fusion of the vocal cords; anterior glottic web extending into the subglottis; combined supraglottic, glottic, and subglottic scarring; and distortion of the larynx after failed LTR). To perform the E-PCTR, the surgical steps are identical to those for PCTR up to Step 5, as described earlier. The surgery is then modified as follows:
A full anterior laryngofissure is done under direct visual guidance to separate the vocal cords and the anterior laryngeal commissure exactly in the midline. The anterior arch of the cricoid is cut open in the midline to expose the glotto-subglottic stenosis. The vocal cord adhesions are carefully incised in the midline to preserve the remaining vocal ligaments, which are important for postoperative voice quality. The glotto-subglottic stenosis is excised along with the tracheostoma if it is close to the stenosis. As in PCTR, the resection margins rest anteriorly to the cricothyroid joint, thereby protecting the RLNs.
The posterior cricoid plate is then divided in the midline avoiding damage to the retrocricoid pharyngeal mucosa. The interarytenoid fibrocicatrical PGS is excised along with the transverse interarytenoid muscle, while preserving the posterior arytenoid mucosa.
The posterior cricoid is sufficiently expanded with a costal cartilage graft harvested from the seventh or eighth rib. The graft must fit flush with the cricoid plate and the perichondrium must be placed intraluminally. Lateral cartilaginous extensions of the graft under the cricoid plate help stabilize the graft, which is fixed in place with 4-0/5-0 Vicryl sutures (Fig. 37.5).
As in PCTR, the trachea is mobilized cranially adding on a laryngeal drop procedure if needed. By resecting one or two additional rings of the tracheal stump distally, a pedicled flap of membranous trachea is created. A new tracheostomy is placed distally leaving at least three vascularized tracheal rings caudal to the thyrotracheal anastomosis.
The posterolateral anastomotic stitch is taken as in a normal PCTR, and the vascularized tracheal flap is sutured with the posterior commissure mucosa using a 4-0/5-0 Vicryl running suture.
The laryngofissure is closed over a stent, meticulously placing a 5-0 Vicryl suture exactly at the level of the vocal cords to restore a sharp anterior commissure. At our institution, we use the Monnier LT-Mold that conforms closest to the inner laryngeal contours thus restoring a normal laryngotracheal airway (Fig. 37.6). This prosthesis exists in 10 different sizes (6 to 15 mm in diameter and a variety of lengths to accommodate the location of the tracheostoma) for use in children and adults. It can be placed intraoperatively and endoscopically. Newly designed metal guide templates help with selection of the appropriate size of the LT-Mold, which is fixed to the thyroid cartilage and trachea by placing two 3-0 Prolene sutures passing transversally through the airway and stent with the knots tied on the outside.
Figure 37.5 Enlargement of the interarytenoid space and cricoid lamina: A rectangular costal cartilage graft, trimmed to the exact thickness of the cricoid plate, is sutured into position with four 4-0 Vicryl sutures, thus restoring an adequate interarytenoid space.
Figure 37.6 Two posterolateral cricotracheal stitches are used as traction sutures to reduce tension on the posterior suture line. The supraglottic portion of the laryngofissure is closed after securely fixing the LT-Mold at the supraglottic level (red thread) with 3-0 nonresorbable Prolene sutures. At the glottic level, a 5-0 Vicryl thread is used to temporarily fix the LT-Mold exactly at the level of the vocal cords (turquoise thread). Precise reapproximation of the anterior laryngeal commissure is essential to avoid postoperative vocal cord synechia. The rest of the anastomosis is done as described for single PCTR (Fig. 37.4).
Surgery
Primary Endoscopic Treatment
• Respect carefully the indications and contraindications to endoscopic treatments
• Use adequate CO2 laser parameters
• Make radial incisions according to Shapshay’s technique and dilate the SGS with an angioplasty balloon or tapered bougies
• Topically apply Mitomycin C (1 to 2 mg per mL for 2 minutes) with a cotton swab on the laser wound
LTR
• Extend the midline thyrotracheal incision from the lower third of the thyroid cartilage down to the first two tracheal rings for an LTR with anterior costal cartilage graft only
• Avoid incising the thyroid cartilage cranially to the anterior commissure of the vocal cords (mid distance from the thyroid notch to the inferior border of the thyroid cartilage) to preserve a good voice in LTR with posterior costal cartilage graft for isolated PGS
• Carve the costal cartilage in an oval shape on the perichondrial side and preserve flanges of cartilage on the opposite side to avoid prolapse of the graft into the airway for an anterior costal cartilage graft
• Always place the perichondrial side of the cartilage grafts facing the subglottic lumen
• Extend the anterior thyrotracheal incision into a full laryngofissure for combined glotto-subglottic stenosis
• Shape the costal cartilage in a rectangular fashion with the perichondrium facing the lumen and preserve lateral flanges of cartilage to wedge the graft between the two divided cricoid laminae for posterior cricoid enlargement
• Secure the airway reconstruction with an appropriate size LT-Mold fixed with 3-0 Prolene sutures placed horizontally through the trachea and the prosthesis
Partial Cricotracheal Resection
• Do not identify the RLNs but carry out the dissection of the lateral wall of the trachea in close contact with the tracheal rings
• Preserve the vascular supply to the trachea from the tracheoesophageal grooves, except over the resected airway segment
• Stay anterior to the cricothyroid joints when resecting the cricoid arch to avoid injury to the RLNs
• Remove all cicatricial tissue from the cricoid plate and flatten it down with a diamond burr to optimize proper adaptation of the tracheal ring used for the anastomosis
• Use meticulous technique when creating the anastomosis
• Keep an anterior cartilaginous wedge pedicled to the tracheal ring used for the anastomosis, perform an inferior midline thyrotomy to enlarge the subglottic lumen and suture the anterior pedicled wedge of the trachea into the luminal defect at completion of the anastomosis
• Perform a laryngeal release when necessary to avoid tension at the suture line
As in conventional PCTR, the lateral and anterior anastomoses are completed. Fibrin glue around the anastomosis allows an airtight closure. The thyroid isthmus and prelaryngeal muscles are resutured in the midline over the anastomosis and the neck incision closed leaving a Penrose drain. A fully mucosalized glotto-tracheal anastomosis along with a posterior subglottic cartilage expansion is thus obtained.
Extended-PCTR in Cricoarytenoid Ankylosis
Cases with severe stenosis and fixation of the CA joints are extremely difficult to manage and often refractory to treatment. In our series of 22 patients with fixed joints, recently, we have attempted to open the CA joint intentionally during open surgery in five cases and have actively remobilized the joint space. We have been encouraged with satisfactory results in three cases. In fact, every attempt should be made to restore mobility in these fixed CA joints since we stand to lose nothing by surgically opening these complex articular spaces.
POSTOPERATIVE MANAGEMENT
Laryngotracheal Reconstruction (LTR)
Patients with long-standing tracheotomies may be colonized with resistant P. aeruginosa or Staphylococcus aureus, hence the importance of the preoperative bacteriologic aspirate.
Appropriate antibiotics are given until complete healing of the subglottic airway is obtained. If reflux is present, proton pump inhibitors are continued for up to 6 months in the postoperative period.
Patients with single-stage LTRs are kept intubated without paralysis for 7 to 14 days, depending on the type of reconstruction used (anterior graft vs. posterior graft). A control endoscopy is mandatory on the day of extubation to ensure proper incipient healing of the reconstructed airway, and then at 3 months if the patient shows no sign of upper airway obstruction clinically.
In double-stage LTRs, the tracheotomized patients may return to the ward on the second postoperative day since the patient’s parents are already familiar with the nursing of the tracheostomy cannula. The first control endoscopy is done at the time of stent removal and then 3 weeks later. Plugging the cannula early after stent removal gives information on the patency of the reconstructed airway above the tracheostoma. If for some reason this is not possible (e.g., suprastomal collapse), then a control endoscopy should be scheduled after another 10 days to ensure that no incipient SGS is redeveloping. When the subglottis is fully healed and stable, downsizing of the cannula over a period of several days facilitates the eventual closure of the tracheostoma.
Partial Cricotracheal Resection (PCTR)
After surgery, nontracheotomized children stay under close supervision in the intensive care unit until extubation is achieved. Select antibiotics based on preoperative cultures and sensitivities, and antireflux medications are given to all patients until a mucosalized anastomosis is obtained. Proton pump inhibitors are continued postoperatively over a period of up to 6 months. Corticosteroids are started only on the day prior to extubation and continued for the following days, if necessary. Depending on the child’s age, a first control endoscopy is performed at 5, 7, or 10 days, postoperatively. If there is only slight-to-moderate edema of the vocal folds and subglottis, then the child is tentatively extubated. Noninvasive face-mask ventilation with continuous positive airway pressure (CPAP) is often used to diminish the inspiratory stridor resulting from the postoperative vocal folds edema. In the case of significant edema, the child is reintubated with a one-size smaller tube, and a plug of corticosteroid–gentamicin ointment is applied to the endolarynx. The next tentative extubation is planned for 2 days later. Additional endoscopic controls are routinely performed at 3 weeks and 3 months. The final result may then be optimized at 3 months by gentle bougienage with Savary–Gilliard dilators, or angioplasty balloons.
If a double-stage PCTR is performed without stenting, then no clinical information on subglottic airway patency is available since the child breathes through the tracheostoma. A control endoscopy at the third postoperative week is then mandatory to assess the quality of healing at the site of the anastomosis. To salvage a suboptimal result (i.e., incipient restenosis), a laryngeal stent (LT-Mold) should be placed endoscopically.
In extended PCTRs and double-stage PCTRs with stenting, the tracheostoma is left in place until complete healing of the subglottic anastomosis is obtained. Stenting is usually necessary for about 3 weeks. However, depending on the complexity of the reconstruction after LTR or extended PCTR, stenting is sometimes maintained for up to 6 months or longer, especially after reconstruction of distorted larynges resulting from previously failed LTRs.
Postoperative Management
• Give select antibiotics based on cultures and sensitivities and antireflux medication until a fully mucosalized subglottis is obtained after LTR, PCTR, and extended PCTR
• Keep the child intubated without paralysis for 7 to 14 days after single-stage LTR
• Keep the child sedated or paralyzed in the intensive care unit for single-stage PCTR with nasotracheal intubation
• Attempt extubation at day 5 or 7 after single-stage PCTR
• Perform control endoscopies prior to extubation and to any reintubation, but routinely at 3 weeks and 3 months postoperatively
• Do not dilate the anastomotic site before the sixth postoperative week
COMPLICATIONS
Surgical failures of LTS may result from insufficient preoperative assessment with inappropriate selection of the operative procedure, failure of the surgical technique, and factors inherent to the patient’s general condition. Needless to say that prior to any surgery, a comprehensive assessment of the child’s airway and general condition is essential (see preoperative planning).
Failure to do so may in fact worsen the initial condition, as is illustrated by the most challenging cases resulting from previously failed surgeries.
The following list of technical errors has been encountered with an LTR:
Off-midline laryngofissure and posterior cricoid split: The vocal cords may be damaged anteriorly and the CA joint posteriorly.
Inappropriate width of the costal cartilage graft: Under- or overexpansion of the posterior laryngeal commissure may lead to an insufficient airway or to a breathy voice with possible arytenoid prolapse and aspiration, respectively.
Poor carving and suturing technique of the costal cartilage graft: Suboptimal mucosal-perichondrial approximation leads to increased superinfection risks, granulation tissue formation, or graft migration with subsequent laryngeal distortion.
Anterior costal cartilage graft reaching the upper edge of the tracheostoma. This may lead to infection and prolapse of the costal cartilage graft into the airway by pressure of the dorsal aspect of the tracheostomy tube during coughing. It is recommended that a single-stage LTR be performed when possible or separation of the graft inset from the tracheostoma by relocating the stoma more distally in the trachea.
Inappropriately designed stent: Additional damage to the reconstructed airway, such as blunting of the anterior laryngeal commissure after vocal cord separation for synechia, and supra- or infraglottic trauma with subsequent granulation tissue formation and restenosis may ensue when using inappropriate stents for the larynx, such as Montgomery T-tubes or Aboulker stents.
Inadequate coverage of the reconstruction: Failure to resuture the thyroid isthmus or the strap muscles over the anterior costal cartilage graft may delay the vascular supply to the reconstructed airway, thereby contributing to graft necrosis.
Additional perioperative conditions such as prolonged steroid usage or inappropriate antibiotic selection may be responsible for graft failure.
After PCTR, three main complications can be encountered: Anastomotic dehiscence, RLN injury, and restenosis.
Anastomotic dehiscence is usually the result of technical errors such as:
Insufficient tracheal mobilization
Absence of laryngeal release when deemed necessary
Undue tracheal devascularization by excessive posterolateral coagulation of the feeding vessels
Inappropriate anastomotic technique
Superinfection of the anastomosis resulting from failure to obtain a bacteriologic aspirate of the airway prior to surgery
Using poor-quality tracheal rings situated close to the tracheostoma in double-stage procedures
And finally, corrosive injury of the subglottis from uncontrolled gastroesophageal reflux
Anastomotic separation can occur early after surgery (≤10 days), or it can become manifest only later as a slowly progressive restenosis. This is likely due to suboptimal mucosal approximation at the anastomotic site, with granulation tissue formation maturing into cicatricial restenosis. If suspicion of dehiscence is confirmed by laryngotracheoscopy at any time during the postoperative course, then immediate reexploration is warranted. It is often possible to salvage the situation by several means, including refreshing the distal tracheal stump by resecting one or two additional rings, performing a full infrahyoid laryngeal release maneuver, mobilizing the intrathoracic trachea extensively, and recreating the anastomosis. For a thyrotracheal anastomosis, the best option is to shroud the laryngeal stitches around the upper edge of the thyroid cartilage with additional reinforcement of the anastomosis using tibial periosteum. If these maneuvers prove impossible, then a T-tube may be introduced through the anterior dehiscence and the trachea secured around it, as a last resort option. The proximal end of the prosthesis must reach the level of the ventricular bands cranially to avoid further damage to the subglottis and vocal cords, and it must be plugged with a cap to prevent aspiration.
In our series of 130 pediatric PCTRs, anastomotic dehiscence occurred in 6/130 (5.2%) of the cases. The risk was significantly less in shorter resections (cricoid + ≤5 rings in 4/114 ∼3.5%) than in longer resections (cricoid + >6 rings 2/16 ∼12.5%).
RLN injury results from failure to follow the basic principles of laryngotracheal surgery, namely dissection of the trachea short of the tracheal rings, preventative coagulation of all tracheal feeding vessels, avoidance of posterior and lateral cricoid dissection above the lower edge of the cricoid plate, section of the lateral cricoid arches anteriorly to the cricothyroid joints, as well as accurate placement of the posterolateral cricoid stitches in a subperichondrial plane during PCTR. All of these technical details must be studied during training in pediatric airway surgery.
Restenosis usually results from a partial slowly progressive dehiscence of the anastomosis with granulation tissue formation that matures into a cicatricial constriction. Sometimes a simple dilatation will suffice to stabilize the situation, but in the most severe cases, revision surgery may be necessary.
RESULTS
Laryngotracheal Reconstruction (LTR)
Upon analysis of the three largest series involving LTR for Grade II to IV SGSs (Table 37.1), the operation-specific and overall decannulation rates were 68% (range: 65% to 70%) and 89% (range: 87% to 97%), respectively. In the published series, the failure rates after surgery were 33% (range: 30% to 35%). To achieve the overall decannulation rates listed in Table 37.1, one to four additional open procedures (with an average of 1.4 per child) were necessary. When compared to Grade II SGS, operation-specific and overall decannulation rates following LTR tended to be less optimal in patients with Myer–Cotton Grades III and IV SGS.
TABLE 37.1 Operation-specific and Overall Decannulation Rates of LTRs from the Largest World Series
Partial Cricotracheal Resection
In the Lausanne series, the results of pediatric PCTRs were stratified into isolated SGS (no cicatricial involvement of the glottis) without and with comorbidities, and glotto-subglottic stenosis without or with comorbidities. The overall decannulation rates of isolated SGS stands at 94%. This figure drops to 86% when the SGS is associated with PGS, vocal fold synechia, or transglottic cicatricial stenosis. When patients present with additional comorbidities, the success rate further drops significantly to 72% (Table 37.2). It must be mentioned, however, that unsuccessful decannulations (8.5% of the whole series of 130 patients) was due to a surgical failure in only three (2.3%) cases. Other reasons for failure of decannulation (eight cases ∼6.2%) were related to severe gastroesophageal reflux in two patients, campomelic dystrophy in one patient, pharyngolaryngeal discoordination, and epiglottic prolapse in one patient, respectively, while three patients are still undergoing treatment.
In the whole series of 130 pediatric PCTRs, we have to report seven (5.4%) deaths, none of which was related to the surgical procedure. One patient died of drug overdose 19 years after the surgery, one from severe aspiration at home, two from a plugged cannula at home, two from severe cardiac problems, and finally one from spondyloepiphyseal dysplasia.
These results lead us to modify the Myer–Cotton Airway Grading System (Table 37.3). This actually makes sense since Grade IIId and IVd stenoses show a statistically significant lower (p = 0.005) decannulation rate in comparison to other groups without comorbidities or glottic involvement.
TABLE 37.2 Decannulation Rates
TABLE 37.3 Modified Myer–Cotton Airway Grading System
In the Cincinnati series published in 2005 on 93 cases, the results are very similar to those obtained in Lausanne, albeit with a slightly lower operation-specific success rate.
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