Congenital tracheal stenosis is a rare disease that benefits from no established surgical procedure due to insufficient experience and a lack of large-scale research.1 If patients develop symptoms early in infancy, surgical repair can be a considerable challenge because the size of the airway is so small that it can be easily obstructed by post-operative oedema.2 If the length of stenotic segment is short, segmental resection and end-to-end anastomosis can be performed, with high success rates.3–6 However, for cases involving the long segment of the trachea, it has been suggested that resection of more than 30% of the tracheal length may lead to excessive anastomotic tension followed by recurrent stenosis or fatal separation.6,7 Long-segment tracheal stenosis is often associated with other anomalies such as pulmonary vascular sling, intracardiac lesion and right-sided aortic arch, which do not occur with with short-segment stenosis.8–10 For these reasons, the management of long-segment tracheal stenosis in infancy still reports significant morbidity and mortality rates.11,12 Various surgical techniques have been suggested for the surgical treatment of this disorder, including rib-cartilage tracheoplasty, peri-cardial patch tracheoplasty, tracheal autograft, and slide tracheoplasty.2,6,11,13–18 Recently, successful results have been reported in several studies.10,11,14,17,19 Nonetheless, there still remains much debate as to the appropriate surgical procedure due to the rarity of the disease and the lack of long-term follow-up data.2,14,17
The limitation on the trachea length that can be resected safely necessitates the introduction of various patch materials for tracheal augmentation. For the patch materials, costal cartilage13 and autologous pericardium have been reported.15 Jaquiss and associates showed favourable results for rib-cartilage tracheoplasty with a low rate of post-operative problems and no operative mortality.14 Backer and associates described an 83% survival rate using peri-cardial patch tracheoplasty.19 Due to its rigidity, cartilage graft cannot offer an airtight suture line. In contrast, peri-cardial patch has an advantage due to its pliability, which allows for an airtight suture line.14
However, its collapsible feature requires the suspension of the patch to the surrounding mediastinal structures and prolonged airway stenting by prolonged intubation during the early healing periods.11,15 One advantage of cartilage graft is its rigidity. This allows the avoidance of prolonged post-operative airway splinting by the endotracheal tube, which is mandatory in the peri-cardial patch technique.14 The patch tracheoplasty is technically simple and desirable, but one problem with this technique is the formation of granulation tissue. Granulation tissue arising from the mesenchymal surface of the patches requires multiple bronchoscopic debridements. Other complications such as necrosis or collapse of the patch may occur.6,19,20 Although several studies claimed that the prevalence of granulation tissue is less frequent than expected,14,17 in our experience all three patients who received peri-cardial patch tracheoplasty developed troublesome granulation tissue. Among these patients, two died of persistent respiratory acidosis caused by granulation tissue.21
To solve this vexing problem, Tsang and associates proposed slide tracheoplasty (as established by Grillo).2,6,18 In this technique, the stenotic segment is divided transversely at its midpoint, the upper stenotic segment is incised vertically posteriorly, the lower stenotic segment is incised anteriorly and then the two are slid together and sutured. After being repaired, the circumference of the trachea should be doubled, creating a nearly four-fold increase in cross-sectional area.2,6 The greatest advantage of this technique over patch tracheoplasty is the immediate reconstruction of the trachea with native tracheal tissue.2,6 As the trachea is lined with normal ciliated tracheal epithelium, there is little tendency to develop granulation tissue.2,6 Additionally, routine post-operative airway splinting is unnecessary, allowing prompt and early extubation. In Grillo’s series, two of seven slide tracheoplasty patients showed a single suture line granuloma that was easily removed by a single bronchoscopy.2 In our own experience, four slide tracheoplasties showed no evidence of granulation tissue. Several authors who favour patch tracheoplasty argued that the actual advantages of slide tracheoplasty should await wider application to a larger series of young patients.14,17 Although Grillo and colleagues presented successful experiences of slide tracheoplasty, only three infants were included in the total of eight cases.6
However, all of our cases of slide tracheoplasty were performed in infancy and resulted in acceptable outcomes.21 Based on our experience, we believe slide tracheoplasty can be safely applied to long-segment tracheal stenosis, particularly in infancy. For slide tracheoplasty, satisfactory subsequent growth was demonstrated experimentally and clinically.22,23 Grillo and colleagues showed that the repaired tracheal segment continued to grow.6 In our experience, we also observed adequate growth in the diameter of the repaired trachea after slide tracheoplasty (see Figure 1). However, because of the relatively small number of patients who underwent long-term follow-up imaging studies, future follow-up studies are required to prove long-term outcome.
Intra-operative Airway Maintenance
There is little agreement on the use of cardiopulmonary bypass for the maintenance of respiration. Many surgeons have found that cardiopulmonary bypass is very useful to achieve excellent operative exposure of the trachea.14,17,19,24,25 Several authors also recommended that cardiopulmonary bypass should be available as a back-up, particularly for small infants or patients with complex cardiac anomalies.14 In contrast, others have preferred to avoid bypass.2,13,18,26 Grillo and associates suggested that the operation can be simplified by avoiding cardiopulmonary bypass.2,6 Use of a high-frequency jet ventilator was also suggested for intra-operative airway management.27 In our series, seven of eight patients received operation under cardiopulmonary bypass. A patient, in whom we did not use cardiopulmonary bypass, died of anastomosis dehiscence, which may be referred to as a technical failure. For us, cardiopulmonary bypass is a useful tool, facilitating the dissection of the trachea without the disturbance of equipment for distal airway maintenance. We feel that it is not necessary to avoid the use of bypass because it can be performed safely.
Selection of Patients
The role of conservative management of congenital tracheal stenosis is not clear. In our experience, five patients did not undergo tracheal surgery because they had no airway symptoms at the time of diagnosis. The patients in this non-operation group required no ventilatory support and their airway abnormalities were incidentally diagnosed during the anaesthetic induction for the repair of cardiac anomalies.
In patients in the non-operation group, the degree of tracheal stenosis tended to be less severe compared with the operation group. However, the size of the stenosis did not seem to be an accurate indicator for tracheal surgery. Although these patients did not receive any correction of their airways, all of them are surviving well without symptoms. Cheng and associates reviewed six patients who had been managed conservatively without surgery using serial CT scan. They found that the tracheas of five patients had grown at a faster than normal rate and the stenotic tracheal diameters approached those of normal diameters by the age of nine years.28 These data, as well as our own experience, suggest that the management of patients with symptomatic congenital tracheal stenosis should be individualised and a selected group of patients can be safely managed non-operatively. We also suggest that the presence of significant respiratory symptoms is the more important factor in deciding to perform tracheal surgery than the diameter of the stenosis itself.
In summary, surgical repair of long-segment congenital tracheal stenosis exhibited high mortality and morbidity rates. As slide tracheoplasty provided relatively good results over short- and mid-term follow-up periods, it seems to be a preferred method for the treatment of long-segment congenital tracheal stenosis in the majority of surgical centres. Patients who need surgical resection should be carefully selected on an individual basis and a multidisciplinary approach is mandatory to achieve a successful outcome for this severe disease.