Congenital Tracheal Stenosis Patients Undergoing Modified Slide Tracheoplasty: Single-Centre Technique and Long-Term Morbidity and Mortality

Background Congenital malformations of the trachea are rare but often life-threatening. Limited data have been published on the outcomes of tracheal reconstruction for congenital tracheal stenosis. We sought to describe the outcomes of patients undergoing tracheal reconstruction over 10 years at our centre. Methods All paediatric patients who underwent long-segment tracheal or bronchial reconstruction from January 1, 2012, to August 31, 2022, were included. The primary outcome was mortality, and secondary outcomes included reoperation and postoperative morbidity. Patients were followed up to 10 years. Results Thirty-three patients with ages ranging from 1 day to 12 years (mean 8.5 months) at the time of tracheoplasty or bronchoplasty were included, with 5 patients undergoing off-pump tracheal reconstruction. The most common preoperative comorbidities included patent ductus arteriosus (30.3%), atrial septal defect (27.3%), and prematurity (24.2%). There were no deaths postoperatively within the follow-up period. All patients experienced successful reconstruction with no patients requiring reoperation of the trachea. A total of 14 patients (42.4%) required postoperative balloon dilation, 3 (9.1%) required bronchial repair after tracheal repair, and 2 (6.1%) required bronchoscopic tracheal debridement. Conclusions This single-centre retrospective study provides a large cohort of congenital tracheal reconstruction patients with a survival rate of 100%, experiencing no mortality during follow-up. The majority of patients had preoperative comorbidities and concomitant congenital cardiac defects. Although tracheal reconstruction continues to be complex with significant postoperative morbidity and mortality, the results of our single-centre study demonstrate the continual advancement of this field and the evolving improvement of postoperative outcomes for these patients.


R ESUM E
Contexte : Les malformations cong enitales de la trach ee sont rares, mais elles menacent souvent le pronostic vital.Peu de donn ees ont et e publi ees sur les r esultats cliniques de la reconstruction trach eale dans les cas de st enose trach eale cong enitale.Notre objectif etait de d ecrire les r esultats obtenus par les patients ayant subi une reconstruction trach eale dans notre etablissement sur une p eriode de 10 ans.M ethodologie : Les donn ees de tous les enfants ayant subi une reconstruction d'un long segment trach eal ou bronchique entre le 1 er janvier 2012 et le 31 août 2022 ont et e incluses dans l' etude.Le critère principal d' evaluation etait la mortalit e et les critères Congenital malformations of the trachea are rare but often life-threatening deformities that affect approximately 1 in 64,500 live births. 1,2In adults, the most common causes of tracheal stenosis are postintubation airway stenosis, tracheoesophageal fistula, trauma, and malignancy. 2,3Congenital tracheal stenosis (CTS), primary tracheomalacia (intrinsic weakness in the cartilaginous wall of the trachea), and secondary tracheomalacia (external compression by anomalous thoracic anatomy) are the most common causes in paediatric populations.CTS is often caused by an absence of the posterior membranous portion of the trachea being replaced by complete tracheal rings. 1,2,4,5CTS can affect any section or length of the trachea (Fig. 1), with long-segment tracheal stenosis generally defined as stenosis affecting >50% of the trachea. 1,6In paediatric populations, presentation most often includes symptoms of stridor and respiratory distress. 7evere congenital malformations of the trachea often require surgical repair.Because of the nature of the surgical procedures, the use of cardiopulmonary bypass (CPB) or extracorporeal membrane oxygenation is often needed. 6,8,9he simplest tracheal reconstruction technique is an end-toend anastomosis involving transecting the trachea, resecting the stenotic segment, and anastomosing the 2 ends.This technique is limited by its ability to address longer lesions.10e12 Another option is a pericardial patch tracheoplasty.This involves creating a vertical incision in the stenotic segment of the trachea that is closed with a pericardial patch enlarging the tracheal segment. 1,6,8,10,13Although definitive surgical repair is the standard of care for these patients, interventional techniques such as tracheal stenting provide a palliative option when surgical intervention is contraindicated. 14The slide tracheoplasty, first described by Tsang et al., 15 involves tracheal transection performed in the midpoint of the stenosis.The trachea is dissected both superiorly and inferiorly.The 2 sections of the trachea are incised in mirror images of each, and the 2 mirror images are then brought together and anastomosed. 1,6,15The final option is a replacement of the trachea with a graft. 3,10,13,16,17lthough surgical intervention has demonstrated significant benefits to these patients, surgical reconstruction is high risk.8e12,18e29 Common complications after tracheal reconstruction include infection, intra-and postoperative bleeding, vocal cord paresis, tracheal obstruction, and growth of tracheal granulation tissue. 4,24Factors that contribute to the difficulty of this repair include complex anatomy, increased incidence of other congenital malformations, and infrequent case presentation.1e 4,12,16,19,21,22,24,25 Tracheal reconstruction is a relatively rare procedure with low volumes even at large referral centres, and thus, previous studies have been limited in their sample sizes.In recent years, larger cohorts of patients who underwent tracheoplasty have been reported, although morbidity and mortality continue to be significant.26e29 Herein, we discuss the surgical approach used at our centre and the outcomes of 33 patients who have undergone tracheal reconstruction with a modified slide tracheoplasty or bronchoplasty.This cohort of tracheal and bronchial reconstruction patients is notable for being among the first to report 100% survival at long-term follow-up in a cohort of this size, with a subset of patients receiving tracheal reconstruction without the use of CPB.

Study cohort
Data were collected for all consecutive paediatric patients who had undergone tracheal reconstruction surgery from January 1, 2012, and February 28, 2022, at the Mazankowski Alberta Heart Institute and Stollery Children's Hospital, a quaternary referral centre in Edmonton, Alberta.The slide tracheoplasty or bronchoplasty was the procedure of choice for all patients with long-segment tracheal or bronchial stenosis.The indications for surgery include the presence of significant tracheal stenosis, the presence of complete tracheal rings on endoscopy or computed tomography scan, and the presence of symptoms.Patients were reviewed by a multidisciplinary team including congenital cardiac surgery, otolaryngology, paediatric intensive care, and anaesthesia, among others before surgery.Exclusion criteria included patients >18 years of age.Thirty-three patients were included in this study with the Results: Thirty-three patients with ages ranging from 1 day to 12 years (mean 8.5 months) at the time of tracheoplasty or bronchoplasty were included, with 5 patients undergoing off-pump tracheal reconstruction.The most common preoperative comorbidities included patent ductus arteriosus (30.3%), atrial septal defect (27.3%), and prematurity (24.2%).There were no deaths postoperatively within the follow-up period.All patients experienced successful reconstruction with no patients requiring reoperation of the trachea.A total of 14 patients (42.4%) required postoperative balloon dilation, 3 (9.1%)required bronchial repair after tracheal repair, and 2 (6.1%) required bronchoscopic tracheal debridement.Conclusions: This single-centre retrospective study provides a large cohort of congenital tracheal reconstruction patients with a survival rate of 100%, experiencing no mortality during follow-up.The majority of patients had preoperative comorbidities and concomitant congenital cardiac defects.Although tracheal reconstruction continues to be complex with significant postoperative morbidity and mortality, the results of our single-centre study demonstrate the continual advancement of this field and the evolving improvement of postoperative outcomes for these patients.secondaires d' evaluation incluaient la r eintervention chirurgicale et la morbidit e postop eratoire.Les patients ont et e suivis pendant 10 ans.R esultats : Trente-trois patients âg es de 1 jour à 12 ans (moyenne de 8,5 mois) au moment de la trach eoplastie ou de la bronchoplastie ont et e inclus dans l' etude, dont 5 ayant subi une reconstruction trach eale sans circulation extracorporelle (off-pump).Avant l'intervention, les affections concomitantes les plus fr equentes etaient la persistance du canal art eriel (30,3 %), la communication interatriale (27,3 %)  majority presenting with congenital long-segment or bronchial tracheal stenosis and one notable case for foreign body aspiration for which the same surgical technique was used (Table 1).Presenting signs and symptoms varied from dyspnea, increased work of breathing, repeated respiratory tract infections, and acute respiratory distress, among others, after which tracheal pathology was confirmed on imaging.Postoperative outcomes and follow-up information were collected from postoperative assessments performed at the Stollery Children's Hospital.

Surgical detail
The standard preoperative imaging was a computerized tomography scan for surgical planning, along with chest radiograph and echocardiography to identify patient anatomy and other concomitant conditions.Surgical technique varied slightly from case to case based on whether or not CPB was required, the patient's comorbidities, and required concomitant surgeries.In general, after median sternotomy and institution of CPB (where applicable), slide tracheoplasty was performed by initially mobilizing the trachea proximally and distally towards the carina preserving important lateral blood supply.The trachea was then mobilized using bipolar cautery or diathermy very close to the trachea to protect the recurrent laryngeal nerve on each side.Bronchoscopy was used to identify the most stenosed portion of the trachea.At the most narrow point, the trachea was divided transversely.A longitudinal incision was then made on the anterior aspect of the lower end of the trachea towards the carina.On the upper segment of the trachea, another longitudinal incision was then made on the posterior aspect through the membranous portion for a similar length as the incision made in the lower trachea.Tracheoplasty was performed using between 5-0 and 7-0 polydioxanone sutures, depending on the patient size, running posteriorly and interrupted sutures at the anterior aspect towards the carina (Figs. 2 and 3).
When performing this anastomosis off pump, the endotracheal tube is pulled back proximally to the incision, and a sterile endotracheal tube is introduced into the field and advanced distally towards the carina and to allow ventilation while the posterior aspect of the anastomosis is performed.Once the posterior anastomosis is complete, the sterile endotracheal tube is removed from the field, and the previous endotracheal tube is advanced across the posterior aspect of the incision allowing for the completion of the anterior anastomosis.This technique allows for continual ventilation of the patient during the tracheal anastomosis without the need for CPB.
Intraoperative bronchoscopy was performed after anastomosis to inspect the trachea.In addition, a Valsalva maneuver is performed to check for anastomotic air leaks.In the case of slide bronchoplasty, the same technique described above is performed on the bronchus with longitudinal incisions made anteriorly and posteriorly, the 2 sides approximated and sutured in the same fashion as described for the tracheoplasty.A piece of autologous pericardium is mobilized with one side still attached and the other placed on top of the anastomosis between the trachea and aorta.Postoperatively at our centre, there is a preference for early extubation on postoperative day 1 or 2, and this was achieved for the majority of patients in this cohort.Postoperative follow-up includes imaging and bronchoscopy performed before discharge and as needed as an outpatient, in addition to follow-up with their primary care physician every 6 months.

Outcomes
The primary outcome was mortality during the follow-up period with patients followed up to 10 years postoperatively.Secondary outcomes include recurrent or residual tracheal stenosis defined by clinically significant stenosis of the trachea after tracheoplasty requiring surgical reintervention, required reoperation and the postoperative complications of vocal cord paresis diagnosed on bronchoscopy, new prolonged tracheostomy >1 month required after surgery, laryngeal paresis, diaphragmatic paresis, acute respiratory distress syndrome, cardiac arrest, cerebrovascular accident, infection, mediastinitis, pericardial effusion, pleural effusion, and pneumothorax.

Operative characteristics
Of the 33 patients who underwent tracheal or bronchial reconstruction surgery, 31 received a slide tracheoplasty and 11 underwent bronchial reconstruction.A total of 28 (84.4%)procedures were performed on CPB, whereas 5 (15.2%) were performed without CPB.The most common concomitant procedures for the included patients included pulmonary artery repair or reimplantation (n ¼ 9) in order to reduce the risk of required reintervention of the pulmonary artery, atrial septal defect closure (9), ligation of the patent ductus arteriosus (8), aortopexy (3), right ventricular to pulmonary artery conduit (2), and ventricular septal defect repair (2) (Table 2).In 3 cases with a left pulmonary artery (LPA) sling, the LPA was not reimplanted.In these cases, the LPA was mobilized significantly and moved anteriorly to the trachea, and at the end of the operation, the LPA was found to have a suitable course without kinking or obstruction, and so they were left without intervention.

Primary and secondary outcomes
The primary outcome of this study was mortality.No patients died during the initial procedure, hospital stay, or during the follow-up period.Patients were followed for a maximum of 10 years with a median follow-up of 4.1 years.Other comorbidities include (n ¼ 1 patient each) aglossia, aortic aneurysm, asplenia, bicuspid aortic valve, choanal atresia, coarctation of the aorta, duodenal atresia, GERD, Goldenhar syndrome, hypoplastic left atrium, intracranial haemorrhage, laryngeal paralysis, micrognathia, neonatal entereocolitis, polyhydramnios, preoperative tracheostomy, previous cardiac surgery, pulmonary arterial hypertension, renal agenesis single umbilical artery, spinal stenosis, tetralogy of Fallot, upper abdominal wall haemangioma, VACTERLsequence, and valvular pathology.

Discussion
Several interesting findings were identified in the analysis of this cohort.First, in contrast to the previous literature that has demonstrated high rates of morbidity and mortality in this patient population, there were no deaths during the follow-up period among the patients at our centre undergoing tracheal reconstruction.This was true despite the majority of the patients included having comorbidities and concomitant congenital defects such as congenital heart defects, esophageal atresia, Goldenhar syndrome, and VACTERL sequence, among others.Second, all patients experienced a successful reconstruction, and no patients required reoperation of the trachea during the follow-up period.Although our maximum duration of follow-up was 10 years, the mean follow-up time was 4.1 years with some patients having shorter durations of follow-up.The surgical techniques used were also notable with the inclusion of 5 cases of slide tracheoplasty performed without the use of CPB along with the addition of a mobilized pericardial patch used to prevent erosion and fistula formation between the trachea and aorta.Finally, the most common postoperative complications included vocal cord, laryngeal, and diaphragmatic paresis.Although these complications and  others have been described in high rates within other cohorts, our cohort was at relatively low risk of developing such complications.
Tracheal reconstruction surgeries are highly complex surgical procedures and require specialized pre-and postoperative care, especially in the context of CTS.Various reconstruction approaches exist and are used based on pathology.Airway management is especially difficult in these patients, and there are often associated congenital cardiac, pulmonary, or abdominal malformations that require concurrent correction and contribute to the increased complexity of these cases. 1,2In addition, tracheal reconstruction surgeries are infrequent resulting in low volumes at individual centres and difficulty for surgeons in attaining significant experience with these cases.7e11,18e29 Although there have been previous publications describing the outcomes of tracheal reconstruction patients with sizeable cohorts including descriptions of cohorts from the Great Ormond Street Hospital, Cincinnati Children's Hospital Medical Center, and those of Zhang et al. 26 among others, our retrospective analysis of 33 patients over 10 years is among the first to demonstrate no mortality on long-term follow-up of a large cohort, including a subset of patients undergoing tracheal reconstruction without the use of CPB.26e29,32 Our centre is a referral centre for all of western Canada resulting in a relatively high concentration of tracheal and bronchial reconstruction procedures performed at our centre with patients from a widespread geographic area.
The slide tracheoplasty has been the procedure of choice for long-segment tracheal stenosis at our centre for the past 10  years.The modified surgical approach used in this cohort includes avoiding the use of CPB and a partially interrupted anastomosis.Several criteria are required for safe off-pump tracheal reconstruction.The patient must not have a concomitant condition requiring repair with the assistance of CPB, there must be a sufficient length of the trachea at the distal aspect of the incision before the carina to allow for the placement of an endotracheal tube and inflation of the cuff for adequate ventilation, and there must be sufficient visualization with the endotracheal tube in place to perform the anastomosis.These criteria are required to facilitate safe off-pump tracheal reconstruction.This technique is also used in patients with extremely low weight who are not able to undergo CPB.In addition, our surgical technique uses an autologous pericardial patch that is harvested leaving one end attached to preserve blood flow.This patch is then placed at the distal anastomosis between the trachea and aorta where the interrupted sutures are placed, which prevents the interrupted suture knots from eroding into the aorta, prevents tracheoaortic fistula formation, accelerates healing, and helps encourage blood supply to the distal trachea.The results of this study demonstrate the success of the slide tracheoplasty procedure and the advances made in the realm of tracheal reconstruction surgery.Several factors have contributed to the exceptional postoperative outcomes experienced at our centre including a modified surgical approach, relatively high volumes allowing for increased experience, and a strong multidisciplinary team including congenital cardiac surgery, otolaryngology, paediatric intensive care, anaesthesia, neonatology, nursing, respiratory therapy, and rehabilitation staff among others.The multidisciplinary team is imperative in safe surgical planning, intraoperative success, and management of postoperative complications.Close follow-up with a multidisciplinary team allows for early identification of complications and optimal management when required.A significant proportion of patients experienced postoperative morbidity including vocal cord or laryngeal paralysis, diaphragmatic paresis, tracheal air leak, tracheocutaneous fistula, and recurrent or residual tracheal stenosis.Similar outcomes have been reported in other studies. 1,11,18,20For example, in a study by Mainwaring et al., 18 of 27 patients who underwent tracheal surgery, 11% experienced postoperative sepsis, 7% experienced prolonged pleural effusions, and 4% experienced heart block or a tracheocutaenous fistula.Sidell et al. 20 reported the outcomes of 52 patients who underwent primary or revision tracheal surgery.Patients most commonly experienced prolonged ventilation (23.1%-38.5%),infection (0%-7.7%),restenosis (3.8%-7.7%),and symptomatic deformities (3.8%-15.4%).Three patients in this study required a prolonged tracheostomy postoperatively, with 2 of these having a tracheostomy preoperatively.In all cases, tracheostomy was required for difficulty ventilating the patients with standard intubation.Among these patients, tracheostomy was recommended for up to 1 year after which the patient would be reassessed for extubation.One patient remains tracheostomy dependent due to several congenital conditions and craniofacial abnormalities resulting in difficulty with respiration.Although morbidity was reported in our study, the most common morbidities were diaphragmatic, laryngeal, or vocal cord paresis with other morbidities occurring infrequently in less than 5% of patients.Strategies have been described for the improvement of postoperative morbidity in this patient population.For example, intraoperative nerve mapping has been used with other surgical procedures in order to avoid intraoperative nerve injuries.One study compared the outcomes of adult patients undergoing tracheal surgery between groups where intraoperative nerve monitoring had been used vs those where it had not.There was no significant difference in rates of nerve injury between the groups. 33In recent years, the field of 3-dimensional printing for modelling and preoperative preparation in tracheal reconstruction surgery has emerged.Three-dimensional modelling allows for a more detailed understanding of the patient's anatomy, allowing the surgeon to anticipate challenging aspects of the surgery, helping to plan cases, and avoid pitfalls.The models also allow for preoperative trials of various techniques allowing surgeons to select the approach that will work best for the individual patient. 34Continued efforts to improve planning in complex cases and avoid common pitfalls such as those described above will contribute to continually improving outcomes for this patient population.
The advanced complexity of patients with CTS and the surgical intervention required for correction will continue to pose challenges in the management of this condition.The localization of these procedures to few centres allows for increased volumes and experience; in addition, a strong team specialized in tracheal reconstruction will provide improved conditions to achieve optimal outcomes.Furthermore, the publication of postoperative outcomes and surgical techniques will continually evolve the knowledge surrounding tracheal reconstruction surgery allowing for collective growth in the surgical approach and interventions for CTS and improvement in the outcomes of these patients.Moving forward, the publication of combined cohorts from multiple centres or the creation of a multicentre registry will allow for the analysis of larger populations of paediatric patients undergoing tracheal reconstruction and may allow for in-depth analyses of factors predictive of outcomes.

Limitations
The retrospective nature of this study is the primary limitation.In addition, this centre has a wide catchment area spanning multiple provinces.This results in some outcomes potentially not being captured by this database.Measures of quality of life such as dyspnea score, phonation, and functional capacity were not captured in this dataset, although they are important for future studies to consider.Finally, although one of the larger cohorts of tracheoplasty patients, the sample size is still small and diverse limiting our ability to identify predictors of outcomes.

Conclusions
In recent years, larger cohorts of tracheal reconstruction patients have been described in the literature, although morbidity and mortality continue to be significant.The results from our single-centre retrospective study provide one of the largest cohorts in the literature to experience no mortality at long-term follow-up and include a subset of patients who received tracheal reconstruction without the use of CPB.Similar to the previous literature, the majority of our cohort had preoperative comorbidities or concomitant congenital defects.Although postoperative complications included vocal cord and laryngeal paralysis, the incidence was relatively low in our cohort compared with previously studied cohorts.Essential to the success of a tracheal reconstruction programme is a strong multidisciplinary team.This team is imperative for preoperative surgical planning, intraoperative success, and postoperative management.Although technically successful, complications during the postoperative course are not uncommon due to the complex nature of these patients.The ability to manage postoperative complications is essential in the care of patients with tracheal stenosis.Although tracheal reconstruction continues to be complex with significant postoperative morbidity and mortality, the results of our single-centre study demonstrate the continual advancement of this field of surgery and the improving postoperative outcomes of these patients.Future studies using larger cohorts of patients are required for a better understanding of predictive factors for postoperative outcomes and quality-of-life metrics in this patient population.

Figure 1 .
Figure 1.Preoperative computerized tomography scan of a 3-week-old patient showing focal tracheal stenosis narrowing to 1 mm immediately superior to the carina (A) and 3-dimensional reconstruction of the trachea (B), computerized tomography scan of a 28-month-old patient with longsegment tracheal narrowing from the level of the aortic arch to the carina, in keeping with complete tracheal rings (C) and 3-dimensional reconstruction of the trachea (D).

Figure 2 .
Figure 2. Image illustrating stenotic segment of the trachea repaired with a slide tracheoplasty (A) and placement of the pericardial flap over the superior vena cava and tracheal suture line (B).SVC, superior vena cava.

Figure 3 .
Figure 3. Bar graphs representing the number of patients based on age at the time of surgery and duration of follow-up.

Figure 4 .
Figure 4. Central image: summary of a single-centre retrospective study of 33 patients who underwent reconstruction for congenital tracheal stenosis.

Table 1 .
Baseline characteristics of patients undergoing tracheal or bronchial reconstruction (N ¼33)

Table 2 .
Operative characteristics of patients undergoing tracheal and bronchial reconstruction (N ¼ 33)