Long-term outcomes of surgical reconstruction for post-tuberculosis tracheobronchial stenosis: a 7-year follow-up in a tuberculosis-endemic region

Introduction

Tuberculosis (TB) remains a global public health threat, ranking as the 13th leading cause of death worldwide and the 2nd leading cause of death among human immunodeficiency virus (HIV) or acquired immunodeficiency syndrome (AIDS) patients. Approximately one-quarter of the global population carries latent TB, with 5–10% developing active disease. Each year, an estimated 10 million new cases and 1.5 million deaths occur (1).

Tracheobronchial TB, a leading cause of benign airway stenosis and affecting 10–40% of pulmonary TB patients (2-7), presents with diverse and often misleading symptoms owing to its variable location and disease stage (8-13). This challenges the timely diagnosis and risk of progression to airway narrowing, lung collapse, and TB reactivation. Despite the World Health Organization (WHO) guidelines and anti-TB therapy, no standard treatment algorithm exists for tracheobronchial stenosis. Interventions includes ablative techniques (electric or laser), balloon dilation to stenting, and tracheobronchial surgery.

Vietnam ranks among the top 30 countries with the highest TB and multidrug-resistant TB burden. In 2019, with a TB incidence rate of 176/100,000 and a mortality rate of 11.8/100,000 (14), Vietnam still lacks routine tracheobronchial TB screening. This leads to late diagnosis and ineffectiveness of conservative interventions, forcing reliance on tracheobronchial surgery for advanced stenotic cases.

Despite this reliance on surgery, long-term outcome data on its effectiveness in post-TB tracheobronchial stenosis are scarce. Our center, with its extensive experience with this procedure, aimed to address this gap through this study. We evaluated the safety and long-term effectiveness of tracheobronchial surgery in treating severe post-TB tracheobronchial stenosis, providing valuable insights for improving patient outcomes and treatment strategies. We present this article in accordance with the STROBE reporting checklist (available at https://jtd.amegroups.com/article/view/10.21037/jtd-24-230/rc).

Methods

Study design and population

This retrospective study was conducted at the Department of Thoracic Surgery, Pham Ngoc Thach Hospital, a tertiary referral hospital for TB treatment in Southern Vietnam. All patients who underwent tracheobronchial surgery for post-TB tracheobronchial stenosis between January 2015 and December 2018 were included in this study. The patients were followed up until December 2022. The study was conducted in accordance with the Declaration of Helsinki (as revised in 2013). The study was approved by the institutional ethics committee of Pham Ngoc Thach Hospital (No. 1595/PNT-HĐĐĐ, dated November 18, 2020) and individual consent for this retrospective analysis was waived.

We included patients who (I) had confirmed pulmonary or tracheobronchial TB, diagnosed and treated with anti-TB therapy for at least three months, with a negative sputum smear for acid-fast bacilli, (II) had severe post-TB tracheobronchial stenosis demonstrated by chest computed tomography (CT) scan and flexible bronchoscopy, with a stenosis diameter exceeding 50% and a lumen size of the stenotic segment of ≤6 mm, (III) developed post-stenotic pulmonary complications such as pneumonia, consolidation, or atelectasis, and (IV) underwent tracheobronchial surgical reconstruction for the treatment of stenosis. We excluded patients with complex post-TB tracheobronchial stenosis involving multiple sites that required different interventions.

Surgical technique

All patients underwent general anesthesia with specific endotracheal tube placement based on stenosis location: tracheal intubation for tracheal stenosis and endobronchial intubation for bronchial procedures. The surgical approach and patient positioning were adapted according to the anatomy involved.

For carinal and right bronchial stenosis, the patients were placed in a 90-degree right lateral decubitus position. A 12–15 cm right posterior lateral thoracotomy in the fifth intercostal space was performed. For left bronchial stenosis, patients were placed in a 90-degree left lateral decubitus position and a 12–15 cm left posterior lateral thoracotomy at the fifth intercostal space was performed. A Carlens double-lumen endotracheal tube was used for anesthesia.

For tracheal stenosis, patients were placed in the supine position. A 4–6 cm transverse neck incision was performed at 2–3 cm above the sternal notch. Partial median sternotomy was combined for stenosis of the lower third of the trachea. Following resection of the stenotic segment, the initial endotracheal tube was replaced with a new endotracheal tube that was directly placed into the distal trachea through tracheal transection. After posterior membranous anastomosis of the trachea, the second endotracheal tube was removed and the initial tube was advanced to continue anesthesia.

In all cases, complete resection of the fibrotic lesions ensured smooth cut ends for anastomosis (Figure 1). Typically, end-to-end anastomosis of the trachea or the main bronchus was performed. In some cases, lobectomy with lobar bronchus anastomosis to the trachea, carina, or main bronchus was performed (Figure 2). We did not use any tissue to buttress the anastomosis due to no signs of active infection. Slide tracheoplasty or bronchoplasty was not performed in any patient due to the fibrotic lesions. Several tension reduction techniques were applied, including tracheal mobilization, neck flexion, hilar mobilization, and division of the inferior pulmonary ligament. For tracheal resections exceeding 3–4.5 cm, chin-to-chest fixation with 1-0 Vicryl sutures was performed for 10 days. For tracheal resections greater than 4.5 cm, hyoid bone release was added.

Figure 1 Preoperative, intraoperative, and postoperative images of a case with left main bronchial stenosis. (A) Left lung collapse on preoperative chest X-ray; (B) left main bronchial occlusion on preoperative chest CT-scan with 3D reconstruction; (C) left main bronchial stenosis on preoperative bronchoscopy; (D) intraoperative image of left main bronchial occlusion; (E) anastomosis of the left main bronchus after resection of the stenotic segment; (F) anastomosis of the carina; (G) postoperative chest X-ray; (H) postoperative chest CT-scan with 3D reconstruction; (I) postoperative bronchoscopy image. CT, computed tomography.

Figure 2 Types of anastomosis. (A) End-to-end anastomosis of the left main bronchus; (B) anastomosis of the left main bronchus to the carina; (C) anastomosis of the left lower lobe bronchus to the left main bronchus; (D) anastomosis of the left lower lobe bronchus to the carina; (E) anastomosis of the left upper lobe bronchus to the left main bronchus; (F) anastomosis of the left upper lobe bronchus to the carina; (G) end-to-end anastomosis of the right main bronchus; (H) anastomosis of the right main bronchus to the trachea; (I) anastomosis of the right intermediate bronchus to the carina; (J) anastomosis of the right upper lobe bronchus to the right main bronchus; (K) anastomosis of the right intermediate bronchus to the right main bronchus; (L) anastomosis of the right upper lobe bronchus to the trachea; (M) end-to-end anastomosis of the trachea.

Anastomosis was performed using 3-0 PDS sutures. We first performed two interrupted sutures to mark and avoid twisting. Continuous sutures were placed in the posterior half. Interrupted or continuous sutures were used for the anterior half depending on the tension of the anastomosis. Anastomotic leaks were checked before the final closure. A neck wound drain and chest tube were placed.

Preoperative and postoperative management

Before surgery, patients were evaluated for their history of TB and anti-TB treatment, symptoms and signs, Karnofsky performance status, modified Medical Research Council (mMRC) dyspnea scale, and spirometry. Diagnostic imaging included chest radiography, chest CT with 3D reconstruction of the tracheobronchial tree, and bronchoscopy. All patients underwent a pre-surgical evaluation by interventionists, but the lesions were not amenable to treatment with endoscopic techniques. Tracheobronchial stenosis was classified into four grades, which is in line with the Myer-Cotton grading system used for subglottic stenosis: mild (stenosis 0–50%), moderate (stenosis 51–70%), severe (stenosis 71–99%), and occlusion (stenosis 100%).

After surgery, the patients were monitored clinically and underwent chest radiography and bronchoscopy. The neck drain was removed when the drainage volume was ≤10 mL in 24 hours and there was no air leak. The chest tube was removed when the drainage volume was ≤100 mL in 24 hours and there was no air leak. Patients were discharged when they were able to perform daily activities, the drains had been removed, the chest radiography showed lung expansion, and bronchoscopy showed no anastomotic stenosis of >50%.

After discharge, the patients were followed up at 1, 3, 6, and 12 months, and annually thereafter. At each follow-up visit, they underwent a physical examination, Karnofsky performance status assessment, mMRC dyspnea scale assessment, chest radiography, and evaluation of complications. We performed bronchoscopies at scheduled intervals (1 day, 1 month, and 1 year after surgery) to monitor patients’ recovery. Additionally, bronchoscopy was performed more frequently if any abnormalities, such as anastomotic stenosis or dehiscence, were identified during previous examinations. A chest CT scan with 3D reconstruction of the tracheobronchial tree and spirometry were performed 1 year after surgery for monitoring lung function improvement.

Outcomes

Safety was assessed based on intraoperative and postoperative complications within 30 days of the surgery. Effectiveness was assessed by the improvement of the Karnofsky performance status, mMRC dyspnea scale, spirometry parameters, and the occurrence of anastomotic stenosis or recurrent tracheobronchial stenosis requiring interventions such as balloon dilation, stenting, or reoperation. Recurrent anastomotic stenosis or tracheobronchial stenosis was diagnosed using flexible bronchoscopy and chest CT scan with 3D reconstruction of the tracheobronchial tree. Reintervention for recurrent stenosis was indicated when the stenosis was >50% or caused complications such as atelectasis.

Statistical analysis

Continuous variables were summarized as mean (standard deviation) or median (interquartile range), and categorical variables were summarized as frequencies (percentages). The long-term outcome (recurrent stenosis requiring intervention) was analyzed using the Kaplan-Meier method and was shown with a Kaplan-Meier curve. The paired t-test, Wilcoxon signed-rank test, and McNemar’s test were used to compare respiratory function parameters and airflow obstruction before and after surgery. Univariable Cox proportional hazards models were used to explore the factors associated with long-term recurrent stenosis. All tests were two-sided, and a P value of less than 0.05 was considered statistically significant. Statistical analyses were performed using R statistical software version 4.1.2.

Results

Fifty patients with post-TB tracheobronchial stenosis underwent tracheobronchial surgical plasty at our hospital between January 2015 and December 2018. We excluded two patients with complex stenosis (long segmental tracheal stenosis with main bronchial stenosis) who were treated with tracheal stenting combined with main bronchial surgical plasty. Finally, 48 patients were included in the study and followed-up until 2022. Surgery was indicated for these patients because endotracheal interventions were failed (2 patients) or lesions were deemed too complex for interventional bronchoscopy (46 patients).

The mean age was 30.6±9.9 years. Females were predominant (91.7%). Most patients had a history of TB (38 patients, 79.2%), and the remaining 10 patients (20.8%) had active TB. The median time from TB diagnosis to tracheobronchial stenosis diagnosis was 12 months (interquartile range, 7–60 months). Most of the patients (89.6%) had only local symptoms. The general condition of the patients was reduced, with 4 patients (8.3%) having moderate dyspnea and most (91.6%) having a Karnofsky score of 70–80. Among 45 patients with preoperative spirometry, there were 31 cases (68.9%) with restrictive lung disease, all of which were mild or moderate, and 12 patients (26.7%) with obstructive lung disease. Three cases were severe, five cases were moderate, and four cases were mild. All baseline characteristics of patients before surgery are shown in Table 1.

Chest radiography showed airway stenosis in only 2 cases (4.2%), but atelectasis in 34 cases (70.8%), pulmonary consolidation in 13 cases (27.1%), and linear fibrosis in 7 cases (14.6%). CT showed similar cases of atelectasis, pulmonary consolidation, and linear fibrosis; however, CT detected 100% of cases with airway stenosis. CT and bronchoscopy determined the location of stenosis was similar, with 3 cases (6.2%) of tracheal stenosis, 36 cases (75%) of left main bronchial stenosis, and 9 cases (18.8%) of right main bronchial stenosis. However, the location of the lesion on the bronchus differed between the CT, bronchoscopy, and intraoperative findings. The results of the CT were similar to those of surgery, with most cases having lesions involving the entire bronchus. Bronchoscopy revealed mostly proximal bronchial stenosis. This may be because the bronchoscope could not pass through the stenotic site. Most lesions were airway fibrosis (93.8%). The degree of stenosis was quite similar between CT and bronchoscopy, with most cases being severe stenosis or occlusion. Full detailed characteristics of the lesions are shown in Table 2.

All patients underwent resection of the stenotic segment and anastomosis, with 27 patients (56.2%) undergoing lobectomy. Pathological findings showed several features suggestive of TB, including Langhans giant cells (45.8%) and caseous necrosis (14.6%). The most common anastomosis technique was lobar bronchus-to-carina anastomosis (33.3%), followed by lobar bronchus-to-main bronchus anastomosis (20.8%), end-to-end main bronchus anastomosis (16.7%), and main bronchus to carina anastomosis (16.7%). Three patients with tracheal stenosis underwent end-to-end anastomosis of the trachea. Five patients (10.4%) required tracheal mobilization, and 45 patients (93.8%) required hilum mobilization. The median surgical duration was 160 minutes, and the median blood loss was 100 mL. Thirteen patients (27.1%) had complications, the most common of which was prolonged air leakage (6 cases, 12.5%). Other complications, including atelectasis (4.2%), hoarseness (4.2%), and cardiovascular complications (4.2%), were less common. No anastomotic leak or dehiscence was observed. All patients with complications were treated conservatively and recovered within one month. Details of surgical techniques and complications are in Table 3.

Table 4 shows that the patients’ condition improved significantly after surgery and was maintained for over 5 years. From 6 months onwards, no patients had dyspnea. Respiratory function also improved significantly at 1 year after surgery (Table 5). The proportion of patients with restrictive lung disease and obstructive lung disease also decreased significantly, and there were no patients with severe obstructive lung disease after surgery.

During the follow-up period, five patients with recurrent stenosis required treatment within the first year after surgery. Of these, three patients were successfully treated with balloon dilation. After reintervention, the patients only had mild stenosis with no subsequent pulmonary complications. The remaining two patients required pneumonectomy and were stable afterwards. The Kaplan-Meier estimate of freedom from recurrent stenosis requiring treatment from one year onwards was 90% (95% confidence interval: 81–99%). We did not find any statistically significant factors associated with recurrent stenosis that required treatment (Table S1).

Discussion

This study demonstrated the safety and effectiveness of tracheobronchial surgery for post-TB tracheobronchial stenosis. While an operative complication rate of 27.1% was observed, all complications resolved with medical management. The 5-year rate of freedom from restenosis was 90%. The performance status, dyspnea severity, and spirometry parameters showed significant improvements postoperatively.

Our study population’s characteristics align with previously reported findings (15-21): a predominance of young females and a higher prevalence of left bronchial involvement with TB. The higher frequency of tracheobronchial stenosis in young females with post-TB remains unclear. However, one hypothesis suggests that sociocultural expectations discouraging women from expectorating phlegm may contribute to prolonged exposure to TB bacilli in the bronchi. As for the greater prevalence of left bronchial involvement, anatomic compression by the aortic arch and the higher incidence of TB in the left-sided mediastinal and hilar lymph nodes are proposed contributing factors. A unique characteristic of our study population was the predominance of airway chronic fibrotic lesions with very narrow lumen diameter. This type of lesion limits the feasibility of airway interventions, potentially making surgery the only definitive treatment option. Additionally, surgery offers the advantage of addressing concomitant lung injuries through lobectomy, which was performed in 56.2% of our cases.

After resecting the airway lesions, the anastomosis technique is crucial to ensure that the anastomosis is not under tension and has an adequate blood supply. We used 3-0 PDS sutures with continuous suturing in the posterior half of the anastomosis. For the anterior half of the anastomosis, we used either a continuous or an interrupted suture technique. In all cases, the anastomosis was not under tension, and the technique was easy to perform. Similarly, a previous study showed that continuous suturing provided sufficient blood supply to the bronchial anastomosis for healing unless the bronchus was excessively mobilized (22).

Anastomotic stricture is a concerning issue that requires monitoring after tracheobronchial reconstruction, particularly for post-TB lesions. The causes can be poor suturing techniques, uneven diameters of the two ends, or dense suturing. Anastomotic inflammation can be caused by sutures and other stimuli, leading to granulation tissue hyperplasia or scarring. In this study, there were five cases of anastomotic stricture of more than 50% causing atelectasis that required intervention, all of which occurred within the first year. Of these, three cases were successfully dilated, and two cases could not be further reconstructed and required pneumonectomy. According to some reports, bronchoscopy can be considered to remove granulation tissue and treat anastomotic strictures with balloon dilation or stenting. However, all these methods have low efficacy. In contrast, incomplete resection of fibrotic lesions and inadequate use of anti-TB drugs after surgery can also lead to late restenosis (23,24). This study did not find any statistically significant factors associated with recurrent stenosis requiring intervention, which may be due to the small sample size and small number of events.

The main limitations of this study are the relatively small sample size and absence of a control group, attributable to the rarity of the disease, which restricts the generalizability of our findings. However, consistent treatment by an experienced team of physicians and the extended follow-up period lend strength to our conclusions regarding the safety and effectiveness of surgical reconstruction for post-TB tracheobronchial stenosis.

Conclusions

Our study demonstrates that tracheobronchial surgery is a safe and effective treatment for severe post-TB tracheobronchial stenosis. Both anastomosis technique and thorough patient follow-up play crucial roles in the success of surgical interventions. The potential for restenosis highlights the importance of careful vigilance and early management. To validate our findings further, future studies with larger sample sizes are warranted.

Acknowledgments

Funding: None.

Footnote

Reporting Checklist: The authors have completed the STROBE reporting checklist. Available at https://jtd.amegroups.com/article/view/10.21037/jtd-24-230/rc

Data Sharing Statement: Available at https://jtd.amegroups.com/article/view/10.21037/jtd-24-230/dss

Peer Review File: Available at https://jtd.amegroups.com/article/view/10.21037/jtd-24-230/prf

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://jtd.amegroups.com/article/view/10.21037/jtd-24-230/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. The study was conducted in accordance with the Declaration of Helsinki (as revised in 2013). The study was approved by the institutional ethics committee of Pham Ngoc Thach Hospital (No. 1595/PNT-HĐĐĐ, dated November 18, 2020) and individual consent for this retrospective analysis was waived.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

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