Cameron D. Wright
INDICATIONS/CONTRAINDICATIONS
Nonoperative observation is appropriate for the child with minimal or no symptoms and an airway that is judged to be adequate to support the child. Prolonged follow-up is necessary as many children develop symptoms with exercise. Most stenotic tracheas grow in proportion to the child’s growth. Occasional patients with congenital tracheal stenosis may not present until later when either exercise or endotracheal intubation uncovers the stenotic trachea. Repair in older children is easier than in neonates so deferral of operation is often wise if the tracheal obstruction is not severe. Infants are often first diagnosed in the midst of a viral syndrome and their respiratory symptoms improve dramatically after resolution of their acute illness. Children like this can usually be observed. Alternatively infants who present with “dying spells” require repair.
PREOPERATIVE PLANNING
A plain chest radiograph is always the starting point of evaluation. Careful examination of the tracheal air column can often give an estimate of tracheal pathology. A barium swallow is useful in infants with malacia and esophageal atresia after repair to exclude recurrent tracheoesophageal fistula. It is also useful to diagnose vascular rings although computed tomography (CT) is now more commonly used and is more definitive. Cross-sectional imaging (CT or magnetic resonance) is very important in evaluating congenital tracheal stenosis (to detect associated anomalies such as a pulmonary artery sling) and extrinsic compression (to detect vascular or cardiac causes of extrinsic compression). CT is more useful in small children as the image time is very short requiring only very short sedation periods. Axial, coronal, and sagittal views, along with 3D reconstruction of the airway allow accurate diagnosis of almost all tracheal lesions. Associated cardiac anomalies should be sought in congenital tracheal stenosis with echocardiography, especially cardiac anomalies that may require concomitant repair (left pulmonary artery sling, ASD, VSD). A pediatric otolaryngologist should examine the larynx in cases of congenital tracheal stenosis to search for other congenital obstructive lesions of the upper airway. If severe pathology is found usually the laryngeal problems are corrected before the tracheal pathology.
Figure 39.1 Bronchoscopic view from just below the vocal cords of a child with congenital O-ring long-segment tracheal stenosis. Notice the circular tracheal rings.
Bronchoscopic evaluation of the airway is the most critical component in evaluation (Fig. 39.1). The extent of the lesion must be evaluated and measured, the quality and extent of normal trachea must be ascertained, and the character of the tracheal mucosa assessed. Malacia is best evaluated during spontaneous breathing, requiring close cooperation with the anesthesiologist.
Infants and small children are evaluated with a very small (infant size) ventilating rigid bronchoscope (Karl Storz, Culver City, CA) with ultrathin 0-degree telescopes. Older children are evaluated with small-sized (4, 5, and 6) ventilating rigid bronchoscopes with the aid of a magnifying 0-degree telescope. Ultrathin flexible bronchoscopes with an outside diameter of only 3 mm are useful for examining infants’ airways and larger standard pediatric flexible bronchoscopes are used for older children. The operating surgeon is the optimal person to assess the airway preoperatively to decide if operation is indicated and to plan the repair. Intraoperative bronchoscopy (by pulling back the endotracheal tube over a flexible bronchoscope) is frequently helpful to decide where to make a tracheal incision and also to examine the completed repair.
SURGERY
Positioning
Patients are operated on in the supine position. Neonates and infants who undergo repair are best done on either cardiopulmonary bypass or ECMO. ECMO has the advantage of allowing transitioning back to the NICU or PICU fully supported without the need for high airway pressures. A small bump under the shoulders is used to extend the head and neck. The head is supported by a gel doughnut. Antibiotics are administered.
Technique
Long-segment congenital stenosis requires a mediansternotomy approach. The anterior surface of the trachea is cleared off from the larynx to the carina dividing the upper pericardium to allow good exposure. Both main bronchi are loosened anteriorly in an areolar plane to allow them to slide up later. Care is taken to avoid too much lateral dissection to avoid interruption of the blood supply of the trachea, which is segmental and enters the trachea along the lateral aspect. The anterior pretracheal plane is areolar and contains no significant blood supply, thus allowing full dissection along this plane. There is also very little blood supply entering posterior to the trachea, so that is another area where more liberal dissection can be done without fear of diminishing blood supply and causing ischemia of the trachea. There is always a balance to be carefully measured when dividing lateral attachments to allow full mobilization and access for anastomotic suturing. In general, less is better. The midpoint of the stenosis is marked and the trachea is then divided transversely at that level (Figs. 39.2–39.5). The endotracheal tube is pulled back to the larynx. In infants usually either ECMO or cardiopulmonary bypass is used for ventilator support. In older children intermittent apneic ventilation can be done with a sterile endotracheal tube on the field. We prefer to open the distal trachea anteriorly down beyond the stenotic segment. This may require going onto one of the two main bronchi if the stenosis involves a bronchus (which is unusual but has been reported). Others have done the opposite and opened the distal trachea posteriorly. The proximal trachea is then opened posteriorly in the midline above the stenosis. The acute angle edges of the divided trachea are rounded off. Stay sutures are placed in the proximal and distal trachea. Circumferential fine absorbable sutures are placed between the proximal and distal trachea. I use 6-0 sutures for neonates, 5-0 for infants, and 4-0 for older children. The two ends of the trachea are brought together and then the stay sutures are tied followed by the anastomotic sutures. The endotracheal tube is advanced into the airway and a leak test is done. The chest is then closed in the routine fashion. Neonates and infants are not extubated and allowed to recover for several days in the ICU before a trial extubation. Older children can be extubated in the OR. Bronchoscopy is performed at the conclusion of the procedure to judge the result and help guide the decision as to when to attempt extubation.
Figure 39.2 Initial approach to slide tracheoplasty. The trachea is divided at the midpoint of the tracheal stenosis. The distal tracheal is opened in the midline anteriorly (solid line). The proximal posterior element of the trachea is dissected off the esophagus while sparing the lateral elements, which contain the blood supply to the trachea. The proximal trachea is opened in the midline posteriorly (blue line).
Figure 39.3 Stay sutures are placed at the two ends of the divided trachea to facilitate their “sliding” together after all sutures are placed. The acute angle edges of the two ends of the trachea are beveled off.
Figure 39.4 All anastomotic sutures are placed about the circumference of the tracheal opening. Once they are in place the two tracheal ends are slid together, the stay suture is tied, followed by tying of all the anastomotic sutures.
POSTOPERATIVE MANAGEMENT
The child is cared for in an intensive care unit for close respiratory observation and ventilator support if needed. As mentioned neonates and infants are left intubated with a small uncuffed endotracheal tube and allowed to recover from the operation typically for several days. If the child is otherwise well and does not need significant ventilator support then a trial extubation is done. These infants are typically rather tenuous and require prolonged intensive care to get them through this procedure. Nutritional support is mandatory. If a child fails extubation the repair must be interrogated with bronchoscopy to ensure there is a reasonable airway. Malacia should be ruled out. Excessive secretions and respiratory infections often lead to longer ventilation times. A control bronchoscopy is usually done prior to discharge and as needed depending on previous bronchoscopy findings (Fig. 39.6).
Figure 39.5 The trachea is now shortened and the cross-sectional area is significantly increased.
Figure 39.6 Bronchoscopic view of the child in Figure 39.1 1 month after slide tracheoplasty demonstrating an enlarged airway.
COMPLICATIONS
Respiratory failure requiring ventilation and airway stenosis/malacia are the most common and important complications following slide tracheoplasty. If residual airway stenosis is identified after operation usually an attempt at dilation is the first step. More distal bronchial stenoses can be uncovered after tracheal repair. In infants these can sometimes be dilated and an uncovered coronary stent inserted to open the airway. Malacia is initially treated by observation and positive pressure airway support. One should ensure there is no undue pressure on the airway externally from mediastinal or vascular structures that may need to be moved off the airway. If malacia remains a problem stenting is the last resort.
RESULTS
Manning et al. recently reported a large series (80 patients) of slide tracheoplasty to treat long-segment congenital tracheal stenosis (median age 9 months, range 7 days to 21 years). The mortality was 5% (4 patients). Cardiac abnormalities were seen in 48 patients and 24 had a simultaneous repair with the trachea (30%). Fifty (63%) were extubated within 48 hours of operation. The median hospital stay was 19 days. Airway reintervention was required in 23 patients (29%) during a median follow-up of 12 months. Multivariate analysis demonstrated that preoperative ventilatory support (p < 0.01), longer cardiopulmonary bypass times (p = 0.002), previous airway operation (p = 0.01), and need for airway reintervention (p < 0.001) as predictors of longer hospital stay.
CONCLUSIONS
Slide tracheoplasty is now widely viewed as the best procedure to repair congenital long-segment circular O-ring tracheal stenosis. The immediate results are very good and long-term follow-up has documented that the repaired trachea grows as the child grows. Congenital heart lesions, especially left pulmonary artery sling syndrome should be repaired at the same time.
Recommended References and Readings
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Hagl S, Sebening C, Springer W, et al. Modified sliding tracheoplasty using the bridging bronchus for repair of long-segment tracheal stenosis. Ann Thorac Surg. 2008;85:1118–1120.
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Manning PB, Rutter MJ, Lisec A, et al. One slide fits all: The versatility of slide tracheoplasty with cardiopulmonary bypass support for airway reconstruction in children. J Thorac Cardiovasc Surg.2011;141:155–161.
Oshima Y, Yamaguchi M, Yoshimura N, et al. Management of pulmonary artery sling associated with tracheal stenosis. Ann Thorac Surg. 2008;86:1334–1338.
Speggiorin S, Torre M, Roebuck DJ, et al. Surgical outcome of slide tracheoplasty in patients with long congenital tracheal stenosis and single lung. Eur J Cardiothorac Surg. 2011;39:170–174.