Slide Tracheoplasty for Long-Segment Tracheal Stenosis

CONGENITAL tracheal stenosis is a rare disorder characterized by the presence of a variable number of complete cartilaginous tracheal rings resulting in a fixed tracheal narrowing. Three morphological subtypes are described: (1) short-segment stenoses involving varying lengths of the trachea, (2) funnel-like long-segment stenoses in which portions of the proximal and the distal trachea may be spared, and (3) generalized long-segment stenoses extending over the entire trachea from cricoid to carina with potential associated mainstem bronchi involvement.¹ Congenital tracheal stenosis may exist as an isolated entity or in conjunction with other anomalies, particularly the pulmonary artery sling complex. Symptomatology is variable, depending on the age of the child, the severity of the stenosis, and the presence or absence of associated anomalies.

Slide tracheoplasty is a reconstructive technique applicable to tracheal stenoses too long for treatment by tracheal resection with end-to-end anastomosis. Slide tracheoplasty reconstruction is a viable alternative to augmentation tracheoplasty techniques that use costal cartilage or pericardium. This surgical approach has been used in 3 children ranging in age from 3 months to 3 years for correction of symptomatic congenital tracheal stenosis. The details of the operative findings and surgical outcomes of these 3 patients are outlined in Table 1 and in Figure 1.

All slide tracheoplasty procedures were performed using inhalation anesthesia, except in the child with the pulmonary artery sling, who required brief intraoperative cardiopulmonary bypass. Inhalation anesthesia is initially administered via a small-bore, preferably cuffed, endotracheal tube placed at the superior aspect of the stenoses.

An anteroinferior cervical collar incision was used in all patients. In 1 patient, this cervical approach alone provided adequate access to the stenotic trachea. One patient required an additional partial upper median sternotomy to a level just below the sternal angle for adequate tracheal exposure. Complete sternotomy and a transpericardial approach to the trachea were necessary only in the child with the associated cardiovascular anomaly.

The upper and lower ends of the stenotic tracheal segment are intraoperatively identified. If precise identification is not possible on surgical exploration alone, another bronchoscopy is performed. Tracheal transillumination via the bronchoscope is used to guide the placement of a 25-gauge needle through the midpoint of the anterior tracheal wall at the presumed proximal end of the stenosis. The endoscopist confirms the needle's location and directs subsequent adjustments. The distal extent of the stenosis is similarly identified using a telescope alone and a brief apneic technique if necessary. Patients requiring intraoperative endoscopic examination are reintubated as described above.

Tracheal dissection is performed circumferentially only around the midpoint of the stenotic segment to prepare for subsequent transection at this level (Figure 2, A). Following transection, the distal trachea is intubated with an appropriate-sized endotracheal tube connected via sterile tubing across the operative field to the ventilator. In cases in which the stenosis extends to the carina, the left mainstem bronchus is selectively intubated; in the event of left mainstem bronchus involvement, the right lung is chosen for selective ventilation. The proximal endotracheal tube is pulled back into the subglottic larynx. The lumen size of the distal endotracheal tube is increased once the distal segment has been incised.

Vertical divisions of the proximal and distal tracheal segments are performed next (Figure 2, A). The proximal segment is incised posteriorly and the distal segment is incised anteriorly; it is essential that the full length of the stenosis be incised. Only limited dissection of the distal tracheal segment is necessary because of the anterior location of the vertical incision. For the upper segment, the posterior incision of the upper segment requires a greater degree of peritracheal dissection, which is minimized as much as possible. The right-angled corners created by the meeting points of the horizontal and vertical tracheal incisions are trimmed to make gently curving corners (Figure 2, B).

A single 3-0 polyglactin suture is placed through the tracheal wall close to the distal tip of the upper segment for proximal traction. Similar distal traction sutures are placed bilaterally either at the tracheobronchial junctions or within the anterior walls of the proximal right and left mainstem bronchi (Figure 2, C).

Tracheal anastomosis is performed with interrupted 5-0 (in infants and young children) or 4-0 (in adolescents) absorbable polyglactin sutures placed approximately 3 mm apart through the full thickness of the trachea so that the future knots will be tied external to the tracheal wall. Suturing is begun proximally and carried in parallel succession distally, the final suture being placed at the distal end of the anterior wall of the upper segment of the trachea. All sutures are carefully held with a hemostat and clipped appropriately to the ipsilateral drapes. After placement of all sutures, the endotracheal tube from above is advanced into either the distal trachea or the appropriate mainstem bronchus to continue ventilation. With cervical flexion and the help of the previously placed traction sutures, the 2 ends of the trachea are approximated. The anastomotic sutures are tied commencing proximally and posteriorly, working down sequentially on both sides until the anastomosis is completed anteriorly and inferiorly (Figure 2, D and E). The endotracheal tube is withdrawn above the reconstructed segment, the cuff is inflated (this is the reason a cuffed tube is initially preferred), and the integrity of the tracheal anastomosis is tested by covering the trachea with saline solution while applying pressure of 30 cm of water to the airway. Once tracheal closure is assured, the sternotomy site (if originally necessary) and cervical incision are closed, the latter following placement of Jackson-Pratt drains. A chin-to-chest suture is used to discourage cervical hyperextension during the initial postoperative course.

Patients are extubated preferentially in the operating room or on arrival in the intensive care unit. The child with the cardiovascular anomaly required 3 days of elective intubation for postoperative ventilatory support. All patients underwent bronchoscopy before discharge. The duration of hospitalization ranged from 8 to 10 days.

Children born with congenital tracheal stenosis may be symptomatic at birth or may not develop symptoms until months or years later when the child's respiratory demands outpace the stenotic airway's ability to maintain adequate ventilation. A male predominance is reported.² Nonspecific noisy breathing, true biphasic stridor with an inspiratory and an expiratory (wheezing) component, recurrent or persistent cough, a tendency toward frequent or prolonged respiratory tract infections, exercise intolerance, and apneic episodes are all potential clinical manifestations, alone or in variable combinations.

Many children who present with such signs and symptoms have no abnormalities on standard roentgenographic chest and/or neck films; tomography and fluoroscopy are diagnostically much more specific in this regard. Detailed radiographic assessment is particularly important in children with tracheal stenoses so severe that complete endoscopic examination is not possible. Tracheal tomography, computed tomography, or magnetic resonance imaging can be used to ascertain length of stenosis and potential mainstem bronchial involvement (Figure 3, A and B). Tracheal cross-sectional area can be accurately calculated from axial computed tomographic images³ (Figure 3, C-E). Magnetic resonance imaging offers the additional advantage of defining associated cardiovascular anomalies (Figure 4, A and B). Endoscopic evaluation is the preferred modality to determine the diameter, length, and morphological pattern or subtype of the tracheal stenosis. The diameter of the stenosis is calibrated by the size of the bronchoscope or telescope that can be passed. All but the most severe stenoses can be completely evaluated this way. Ultrathin flexible bronchoscopes can be passed through rigid bronchoscopes to examine severely stenotic distal airways. Flexible laryngoscopy is also useful preoperatively in determining true vocal fold mobility.

Cardiovascular anomalies are documented in up to 50% of children with congenital tracheal stenosis.⁴ Such anomalies include atrial septal defects, ventricular septal defects, and, most frequently, an aberrant left pulmonary artery resulting in the pulmonary artery sling complex. The preoperative identification of such anomalies is crucial because they contribute to perioperative morbidity, influence the operative approach, and can often be corrected at the time of the reconstructive tracheoplasty.

Children with endoscopically confirmed complete tracheal rings who have minimal symptoms may be cared for conservatively with periodic endoscopic evaluations, delaying surgery until exercise or activity intolerance prompts intervention. Flow-volume pulmonary function tests may be of help in assessing the physiological severity of the tracheal stenosis in patients old enough to undergo such studies.

Symptomatic children with short-segment congenital tracheal stenoses may be candidates for tracheal resection with end-to-end anastomosis.^{5 - 8} Pretracheal mobilization with cervical flexion, enhanced only if necessary by suprahyoid laryngeal release, will usually safely permit resection of up to 40% of the length of the juvenile trachea. Children, however, seem less tolerant of anastomotic tension than adults, with a subsequent higher risk of stenosis at the anastomotic site.^{7 ,9}

Unfortunately, many children with congenital tracheal stenosis have long-segment stenoses not amenable to resection and reanastomosis. Augmentation tracheoplasty has become the preferred surgical treatment in many centers for the management of such long-segment congenital tracheal stenoses. Autologous costal cartilage or pericardium are most commonly used.

The use of a costal cartilage graft in the reconstruction of long-segment congenital tracheal stenosis was initially reported by Kimura et al.¹⁰ Subsequent authors have elaborated on this technique,^{2 ,11 - 13} including application of the principles of single-stage laryngotracheoplasty reconstruction to this particular anomaly.¹⁴ A major problem with augmentation tracheoplasty using costal cartilage is the need for multiple bronchoscopies due to recurrent granulation tissue formation at cartilage graft sites.² The decreased duration of stenting associated with the single-stage approach seems to lessen this problem.¹⁴ The mesenchymal surface of the cartilage becomes epithelialized in time. Advocates of cartilage graft tracheoplasty note that cartilage, compared with pericardium, has greater inherent support, which may be of particular benefit in distal stenoses involving the carina or mainstem bronchi, where stenting is most troublesome. Proponents of cartilage augmentation tracheoplasty also note the ease of costal cartilage harvesting and argue that the pericardium is outside the operative field if cervical dissection of the trachea without sternotomy provides sufficient surgical access to the stenotic trachea.

Idriss et al¹⁵ first described the use of autologous pericardial patch grafting for augmentation tracheoplasty. This experience has been subsequently updated,^{16 - 17} and this technique has been used and reported on by other investigators as well.^{2 ,18 - 19} Pericardial patch augmentation tracheoplasty requires extracorporeal circulation, complete sternotomy, and wide exposure of the trachea via a transpericardial approach. The stenotic trachea is incised vertically and the pericardial patch sutured into place; the patch is suspended to the innominate artery and the artery is suspended to the sternum. Endotracheal intubation and mechanical ventilation are necessary for approximately 1 week postoperatively. The pericardial patch has been shown to be replaced by mature scar tissue in the graft site and to completely reepithelize with pseudostratified ciliated columnar epithelium.²⁰ Pericardial patch contracture can occasionally occur with recurrent stenosis; revision augmentation tracheoplasty using costal cartilage grafts has been used in such cases.¹⁷ The greatest morbidity of pericardial patch augmentation tracheoplasty is a similar tendency toward granulation tissue formation. Such granulomas typically occur at the distal end of the endotracheal tube stent and can be a significant cause of perioperative morbidity in up to 70% of patients who have undergone augmentation tracheoplasty technique.² In a series of 18 patients specifically undergoing pericardial patch augmentation tracheoplasty, bronchoscopy was required for débridement a mean of 3.8 times in infants with stenoses extending to the lower third of the trachea; bronchoscopy frequency increased to 16.0 and 16.8 times when the stenoses extended to the carina and mainstem bronchi, respectively.¹⁷

The mortality in children with congenital tracheal stenosis treated conservatively with tracheotomy and intensive respiratory care is approximately 35%.²¹ A more recent review of 18 patients with congenital tracheal stenosis, 15 of whom were treated surgically, reveals the mortality of this disorder to remain quite high at 47%.² The largest series assessing pericardial patch augmentation tracheoplasty documents a significantly improved mortality of only 17% in a notably high-risk population; 25% of the patients still required tracheotomy after tracheal reconstruction for either clearance of secretions or distal stenting.¹⁷ Tracheal involvement within 1 cm of the carina or involvement of either mainstem bronchus increased the risk of tracheotomy tube dependence and the likelihood of fatal outcome.

The slide tracheoplasty technique as outlined in this article was originally described by Tsang et al²² and subsequently modified by Grillo.²³ The reconstructed stenotic segment is shortened by one half its length. The circumference of the reconstructed trachea is doubled by this procedure, with a resultant 4-fold increase in its cross-sectional airway area. This area increase is actually slightly less due to the bilobate shape of the reconstructed lumen (Figure 5). Although the resultant airway is not of normal diameter, the approximate 4-fold increase in cross-sectional area seems to be sufficient from a clinical standpoint as indicated by the near-complete symptomatic relief achieved in these 3 children.

Initial concerns regarding possible disruption of the trachea's lateral segmental arterial blood supply have not been realized. This is attributed in part to limiting circumferential dissection to the midpoint of the stenotic trachea at the site of planned transection. The distal segment, given its anterior vertical incision, is left fairly intact, and an effort is made to limit peritracheal dissection in the proximal segment to only that necessary to make the posterior vertical incision and slide the trachea.

The greater than 4-year follow-up of 2 of the children in this series demonstrates steady growth of the reconstructed hemitracheal rings proportional to that of the growth of the overall trachea. Such growth is not unexpected given the documented cross-sectional area enlargement of complete cartilaginous rings in children with tracheal stenosis who have not required surgery.²⁴ Tracheal growth after slide tracheoplasty repair has also been experimentally confirmed.²⁵

Advantages of the slide tracheoplasty technique for reconstruction of congenital long-segment tracheal stenosis are severalfold. Reconstruction is performed with the patient's native tracheal tissues, negating the need for autologous augmentation cartilage or pericardium. As such, there is less extensive surgical dissection, decreased likelihood of subsequent mediastinal complications, and avoidance of the need for cardiopulmonary bypass in the absence of coexistent cardiovascular anomalies. More important, prolonged endotracheal intubation for ventilation and stenting purposes is not necessary; only the child with the coexistent pulmonary artery sling in this series was intubated beyond the first postoperative day. The avoidance of both an endotracheal tube stent and a mesenchymal tissue graft results in a near-complete absence of granulation tissue and a markedly reduced need for therapeutic postoperative bronchoscopies.

These observations suggest that slide tracheoplasty may well be considered the procedure of choice for long-segment congenital tracheal stenoses. Additional cases and longer follow-up are needed before its role as an alternative to augmentation tracheoplasty is established in children whose long-segment stenoses are complicated by mainstem bronchi involvement or associated cardiovascular anomalies.

Accepted for publication July 21, 1997.

Presented at the 12th Annual Meeting of the American Society of Pediatric Otolaryngology, Scottsdale, Ariz, May 15, 1997.

Reprints: Michael J. Cunningham, MD, Massachusetts Eye and Ear Infirmary, 243 Charles St, Boston, MA 02114.