Abstract
Background
With the rapid development of critical care medicine, tracheal intubation and tracheotomy are increasingly used. Meanwhile, the number of tracheal stenosis cases, as one of the complications, is gradually rising. Bronchoscopic interventional treatment is quite effective for tracheal stenosis. However, the differences in treatment effects between post-intubation tracheal stenosis (PITS) and post-tracheostomy tracheal stenosis (PTTS) remain unclear. Also, there is a lack of in-depth and systematic exploration on the distinctions between these two types of tracheal stenosis with different causes. Thus, this article will describe and compare PITS and PTTS in detail, explore their differences and differences in treatment effects, aiming to provide a basis and guidance with certain reference value for clinical medical practice.
Methods
In this cross-sectional observational study, the data of PITS and PTTS patients undergoing bronchoscopic interventional therapy in the Department of Respiratory and Critical Care Medicine II, and Oncology Department of Emergency General Hospital and the Department of Respiratory Medicine in Dongzhimen Hospital of Beijing University of Chinese Medicine were retrospectively analyzed.
Results
The PTTS group had a higher prevalence of neurological diseases and burns, with more common dynamic stenosis; the PITS group was more commonly associated with drug poisoning respiratory, digestive, and circulatory system diseases, with scar tissue being more prevalent (P<0.05). Stenosis length was significantly longer in the PTTS than in the PITS. In terms of treatment modalities balloon dilatation and scleroscopic laser were more frequently used in the PITS group than in the PTTS group (P<0.05). After treatment, both groups showed significant reductions in the degree of stenosis and modified Medical Research Council (mMRC) scores, with a significant increase in Karnofsky Performance Status (KPS) scores (P<0.05), and a significant improvement in the degree of endoscopic stenosis (P<0.05). The PTTS group had fewer average hospitalizations and longer intervals between the two hospitalizations (P<0.05).
Conclusions
The clinical characteristics of the two patient groups are different. Bronchoscopic intervention showed significant efficacy on PITS and PTTS, with a more pronounced improvement in KPS scores in PTTS patients.
Keywords: Tracheostomy, tracheal intubation, mechanical ventilation, tracheal stenosis, bronchoscopic intervention
Highlight box.
Key findings
• There are differences in the characteristics of post-intubation tracheal stenosis (PITS) and post-tracheostomy tracheal stenosis (PTTS), the effect of bronchoscopic interventional treatment is remarkable.
What is known and what is new?
• PITS and PTTS is a chronic and recurrent disease.
• There are differences in the clinical features between PITS and PTTS.
What is the implication, and what should change now?
• PITS and PTTS should be regarded as two distinct entities, the differences in the occurrence mechanisms of the two should be explored in depth in the future.
Introduction
Benign tracheal stenosis is caused by various benign lesions leading to tracheal narrowing, including iatrogenic factors such as post-intubation tracheal stenosis (PITS) and post-tracheostomy tracheal stenosis (PTTS), infections, external compression, benign tumors within the tracheal, and gastroesophageal reflux disease. This condition can lead to varying degrees of dyspnea, and in severe cases, death by asphyxiation; with tracheostomy and/or tracheal intubation being the primary causes, accounting for 54.7% (1,2). Studies have shown that there is no significant difference in the occurrence rate of PITS and PTTS, ranging from 10% to 22% (3-5). PITS is mainly due to traumatic intubation, prolonged intubation time, and high cuff pressure in the endotracheal tube (6). PTTS is primarily caused by excessive force during the tracheostomy, local ischemic necrosis, infection at the tracheostomy site, high tracheostomy, and friction between the distal end of the tracheal tube and the tracheal wall (7). Patients with these conditions often present with symptoms of dyspnea, cough, and sputum production, which are often misdiagnosed as asthma or acute exacerbations of chronic obstructive pulmonary disease (COPD), leading to delayed diagnosis (8). In severe cases, this can pose a life-threatening risk; therefore, early diagnosis is critically important, and the bronchoscopic interventional technique plays a key role in the definitive diagnosis and treatment of stenosis.
Currently, the treatment methods for benign tracheal stenosis mainly include surgical resection, drug therapy, and bronchoscopic interventional therapy. Surgical resection is the primary method for surgical treatment; however, it is difficult to implement widely due to the high demands of surgical techniques, significant risks, prolonged stenosis length, or poor cardiopulmonary function in patients (9). Drug therapy is also an option, with current medications for treating benign tracheal stenosis mainly including antibiotics, corticosteroids, and mitomycin, which primarily suppress the inflammatory and proliferative responses during tracheal scar formation. However, drug therapy is generally used as an adjunctive treatment (10). With the development and application of bronchoscopy, various interventional techniques have been widely adopted, gradually replacing surgical treatment (11). Interventional bronchoscopy methods, including balloon dilation, electrocautery, laser, argon plasma coagulation (APC), cryotherapy, T-tube and silicone stent implantation, are less invasive and can rapidly relieve shortness of breath (12). Studies have shown that although there is no significant difference in the incidence of complications between PITS and PTTS, the characteristics of the two patient groups and the features of tracheal stenosis are different. Consequently, the treatment approaches for PITS and PTTS vary, and the treatment effectiveness also differs, indicating that they should be considered as two distinct entities (7,13,14).
However, there are few comparative studies on the differences between PITS and PTTS reported domestically and internationally, and there is a lack of large sample size studies. This research collected data from a total of 422 patients from the Department of Respiratory and Critical Care Medicine II and Oncology Department of Emergency General Hospital and the Department of Respiratory Medicine of Beijing University of Traditional Chinese Medicine Dongzhimen Hospital to explore the differences in general information, clinical data, and the efficacy of bronchoscopic treatment for patients with PITS and PTTS, aiming to provide certain clinical evidence. We present this article in accordance with the STROBE reporting checklist (available at https://jtd.amegroups.com/article/view/10.21037/jtd-2024-2226/rc).
Methods
Study design and participant selection
This is a cross-sectional study. Patients with a history of tracheal intubation or tracheotomy among those diagnosed with benign airway stenosis in the Department of Respiratory and Critical Care Medicine II, and Oncology Department in Emergency General Hospital from 2010 to 2019 and in the Department of Respiratory Medicine in Dongzhimen Hospital of Beijing University of Chinese Medicine from 2020 to 2023 were collected. The study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. The study was approved by the Ethics Committees of Emergency General Hospital (No. K24-24) and Dongzhimen Hospital of Beijing University of Chinese Medicine (No. 2024DZMEC-039-01). Individual consent for this retrospective analysis was waived.
The diagnostic criteria are as follows: referring to the “Expert Consensus on Interventional Diagnosis and Treatment of Benign Central Airway Stenosis via Bronchoscopy” published by the Chinese Medical Association and the Respiratory Disease Branch of the Chinese Medical Association in 2017 (15), iatrogenic tracheal stenosis can be diagnosed based on medical history, bronchoscopy results, and pathological results. (I) Medical history: having a history of tracheotomy/tracheal intubation; (II) symptoms and signs: the main symptom is dyspnea, and the secondary symptoms include cough, expectoration, and hoarseness. Different degrees of wheezing can be heard during pulmonary auscultation; (III) auxiliary examinations. Bronchoscopy: it is the “gold standard” for diagnosing airway stenosis; imaging examinations: High-resolution computed tomography (HRCT) can clearly show the type of tracheal stenosis (intraluminal, extraluminal, or mixed), whether the distal end of the stenosis is unobstructed, the length and diameter of the lesion, and the relationship with the surrounding large blood vessels; pathology: excluding tracheal stenosis caused by malignant tumors.
The inclusion criteria are as follows: (I) patients with iatrogenic tracheal stenosis who meet the diagnostic criteria; (II) aged 18 years or older, regardless of gender. Those who meet both above two criteria can be included.
The exclusion criteria are as follows: (I) patients with tracheal stenosis caused by secondary malignant tumors of the lungs and airways; (II) those with severe organic diseases such as of the liver, kidneys, and heart; (III) airway stenosis caused by non-scarring lesions such as tracheopathia osteoplastica and relapsing polychondritis; (IV) those with mental disorders or a history of drug or substance addiction. Anyone who meets one of the above four items will be excluded.
Data collection
General information, including age, gender, the degree of preoperative endoscopic tracheal stenosis, modified Medical Research Council (mMRC) score (16), Karnofsky Performance Status (KPS) score (17), etc.
Collect data such as primary diseases, stenosis sites, stenosis degree classification, stenosis nature, bronchoscopic treatment methods, complications, the number of hospitalizations within 12 months and the total number of hospitalizations, the average length of hospital stay interval within 12 months and the total length of hospital stay interval (excluding patients who were only hospitalized once from the length of hospital stay interval), etc., to compare the differences between the two groups of patients.
Information about tracheal stenosis: including the primary disease, location of the stenosis, grading of stenosis severity, bronchoscopic treatment methods, complications, the number of hospitalizations within 12 months and the total number of hospitalizations, the average length of hospital stay interval within 12 months and the total length of hospital stay interval (excluding patients who were only hospitalized once from the length of hospital stay interval), etc., to compare the differences between the two groups of patients. Location of stenosis: for ease of localization, the location of the stenosis was divided according to the eight-zone method of the central tracheal (18). Severity of stenosis: classified according to the five-grade classification system (19). The eight-zone method of the tracheal was proposed by Wang Hongwu from China, which can more accurately locate the central tracheal. Divide the main trachea into three parts: upper, middle and lower, corresponding to zones I, II and III; the carina is numbered as zone IV; the right main bronchus is numbered as zone V; the right intermediate bronchus is numbered as zone VI; the proximal half of the left main bronchus is zone VII; the distal half of the left main bronchus is zone VIII, as shown in Figure 1. The degree of high-level tracheal stenosis is usually graded according to the Myer-Cotton classification, but this is not suitable for the entire central tracheal. Professor Wang Hongwu adopts a 5-grade classification method. When the tracheal stenosis is at grade 1, no special treatment is required for bronchoscopy. When the lesion blocks or compresses the trachea, causing the degree of luminal stenosis to be ≥ grade 4, the patient will experience obvious dyspnea and should be treated as an emergency, as shown in Table 1.
Figure 1.
The eight-zone method of the tracheal.
Table 1. Grading of tracheal stenosis.
| Classification | The degree of stenosis of the pipe diameter (%) | |
|---|---|---|
| Wang’s grading | Myer-Cotton grading | |
| Level I | ≤25 | – |
| Level II | 26–50 | ≤50 |
| Level III | 51–75 | 51–70 |
| Level IV | 76–90 | 71–99 |
| Level V | 91–100 | 100 |
Treatment methods
We adopt a combination of multiple endoscopic methods for treatment. Based on the preliminary judgment of the stenosis location and degree by preoperative chest computed tomography (CT), appropriate sizes of rigid and flexible endoscopes are selected. After excluding preoperative contraindications, bronchoscopic diagnosis and treatment are carried out. Surgical procedure: after general anesthesia, a rigid bronchoscope is inserted through the oral cavity or tracheotomy. Then, a flexible bronchoscope is inserted through the rigid bronchoscope. The type, degree, length, and location of the stenosis are determined. After evaluating the condition, appropriate bronchoscopic methods are used (Snare device, cryotherapy, balloon dilation, rigid bronchoscope dilation, rigid bronchoscope excision, laser under rigid bronchoscope, stent, APC, electrocautery, T tube). The improvement of the stenosis and the occurrence of postoperative complications are evaluated. The bronchoscope is withdrawn, and the operation is completed. We usually perform the second flexible bronchoscopy 3 days later to evaluate the surgical results. The choice of treatment methods is shown in Figure 2. Our team generally adopts combined treatment under bronchoscopy, which has a better effect. For cicatricial stenosis, balloon dilation and carbon dioxide cryotherapy are mostly used. For granulomatous hyperplastic lesions, snare and carbon dioxide cryotherapy have a good effect. However, which treatment methods to combine still need to be determined according to the condition of the patient, and it is not invariable.
Figure 2.
Treatment strategy.
Statistical analysis
Univariate analysis
The data of patient age were normally distributed and analyzed by T-test. Data on number of hospitalizations, interval between the two hospitalizations, degree of stenosis before and after bronchoscopic intervention, mMRC scores, and KPS scores were non-normally distributed and analyzed using the Mann-Whitney U test. Chi-square tests were used to analyze gender, primary disease, location of stenosis, narrow length, grading of stenosis severity, and narrow types, complications, treatment methods. Continuous variables are expressed as mean ± standard deviation, while categorical variables are presented as numbers (percentages). All analyses were performed using Statistical Product and Service Solutions (SPSS) 26.0 statistical software, and P<0.05 was considered statistically significant.
Logistic regression analysis
Variables with P<0.05 in univariate analysis and some confounding variables were included in the logistic regression analysis to explore the differences between the PITS and PTTS, including age, gender, etiology, stenosis type, treatment method, complications, number of hospitalizations within 12 months, and average length of hospital admission interval within 12 months. Hosmer & Lemeshow (0.814) and Nagelkerke R2 (0.423) were used to evaluate the goodness of fit of the model. Odds ratios were reported with 95% confidence intervals (CIs). Since this was an exploratory study, the sample size was not calculated, and we included as many patients as possible. All statistical analyses were conducted using SPSS 26.0 statistical software, P<0.05 indicated statistical significance, and graphs were created using GraphPad Prism software.
Results
General information of patients
Figure 3 shows the flowchart of the research process. Eventually, 422 patients were included, with an average age of 45.7 years. Among them, 296 (70.1%) were male. 169 patients underwent intubation (40.0%), with an average age of 46.7 years and 120 being male (71.0%); 253 patients underwent tracheostomy (60.0%), with an average age of 45.7 years and 176 being male (69.6%), as shown in Table 2. There were no statistically significant differences between the two groups in terms of age (P=0.54), gender (P=0.75).
Figure 3.
The flowchart of the research process.
Table 2. General information of patients.
| Category | PITS (n=169) | PTTS (n=253) | P value | χ2 value |
|---|---|---|---|---|
| Age (years) | 46.7±18.0 | 45.7±19.5 | 0.54 | – |
| Gender | ||||
| Male | 120 (71.0) | 176 (69.6) | 0.75 | 0.1 |
| Female | 49 (29.0) | 77 (30.4) |
Continuous variables are expressed as mean ± standard deviation, while categorical variables are expressed as numbers (proportions). PITS, post-intubation tracheal stenosis; PTTS post-tracheostomy tracheal stenosis.
Tracheal stenosis information
In terms of primary diseases, drug poisoning (P=0.04) and circulatory system (P<0.001) and were more common causes for intubation, while neurological system (P<0.001) and burns (P=0.002) were the most common reasons for tracheostomy. There was no statistically significant difference in the location of stenosis between the two groups (P=0.69), with both groups primarily concentrated in a single area; the intubation group had 86.4% in a single area, while the tracheostomy group had 85.0% in a single area. The classification of stenosis severity was predominantly at grade 3 or higher, with the intubation group accounting for 74.0% and the tracheostomy group accounting for 69.6%. In terms of the type of the stenosis, scar tissue was more common in the intubation group (P<0.001), while dynamic stenosis was more common in the tracheostomy group (P<0.001). In terms of narrow length, the tracheotomy group is often longer than the tracheal intubation group (P<0.001). In the selection of treatment methods, balloon dilation (P<0.001), electrocautery (P=0.01), and laser under rigid endoscope (P=0.03) are more commonly selected for tracheal intubation. The tracheotomy group more frequently selected the three methods of stent (P<0.001), snare device (P=0.01), and T-tube (P<0.001). In terms of complications, the tracheotomy group was more prone to bleeding than the tracheal intubation group (P=0.009), as shown in Table 3.
Table 3. Tracheal stenosis information.
| Category | PITS (n=169) | PTTS (n=253) | P value | χ2 value |
|---|---|---|---|---|
| Primary disease | ||||
| Respiratory system | 16 (9.5) | 12 (4.8) | 0.056 | 3.651 |
| Neurological system | 19 (11.2) | 86 (34.0) | <0.001* | 28.055 |
| Circulatory system | 48 (28.4) | 16 (6.3) | <0.001* | 38.387 |
| Drug poisoning | 15 (8.9) | 10 (4.0) | 0.04* | 4.406 |
| Trauma | 43 (25.4) | 80 (31.6) | 0.17 | 1.872 |
| Burn injuries | 2 (1.2) | 21 (8.3) | 0.002* | 9.959 |
| Digestive system | 13 (7.7) | 13 (5.1) | 0.29 | 1.143 |
| Others | 13 (7.7) | 15 (5.9) | 0.48 | 0.509 |
| Location of stenosis | ||||
| Single area | 146 (86.4) | 215 (85.0) | 0.69 | 0.163 |
| ≥2 areas | 23 (13.6) | 38 (15.0) | ||
| Degree of stenosis | ||||
| Grade 1 | 10 (5.9) | 9 (3.6) | 0.25 | 1.312 |
| Grade 2 | 34 (20.1) | 68 (26.9) | 0.11 | 2.526 |
| Grade 3 | 55 (32.5) | 74 (29.2) | 0.47 | 0.518 |
| Grade 4 | 65 (38.5) | 92 (36.4) | 0.66 | 0.191 |
| Grade 5 | 5 (3.0) | 10 (4.0) | 0.59 | 0.292 |
| Nature of stenosis | ||||
| Scar tissue | 69 (40.8) | 62 (25.4) | <0.001* | 12.610 |
| Granulation tissue | 36 (21.3) | 58 (22.9) | 0.70 | 0.154 |
| Scar and granulation tissue | 59 (35.0) | 86 (34.0) | 0.85 | 0.038 |
| Dynamic stenosis | 5 (3.0) | 47 (18.6) | <0.001* | 22.877 |
| Narrow length | ||||
| ≤1 cm | 125 (74.0) | 112 (44.3) | <0.001* | 36.290 |
| >1 cm | 44 (26.0) | 141 (55.7) | ||
| Treatment method (first time) | ||||
| Cryotherapy | 126 (74.6) | 184 (72.8) | 0.68 | 0.174 |
| Balloon dilation | 98 (58.0) | 98 (38.8) | <0.001* | 15.099 |
| Rigid bronchoscope excision | 25 (14.8) | 33 (13.0) | 0.61 | 0.262 |
| Rigid bronchoscope dilation | 27 (16.0) | 29 (11.5) | 0.18 | 1.794 |
| Laser under rigid bronchoscope | 19 (11.2) | 14 (5.6) | 0.03* | 4.581 |
| Stent | 11 (6.5) | 54 (21.3) | <0.001* | 17.112 |
| Electrocautery | 44 (26.0) | 41 (16.0) | 0.01* | 6.087 |
| APC | 19 (11.2) | 42 (16.6) | 0.15 | 2.352 |
| Snare device | 28 (16.6) | 69 (27.3) | 0.01* | 6.559 |
| T tube | 0 | 18 (7.1) | <0.001* | 12.559 |
| Complications | ||||
| Bleeding | 31 (18.3) | 75 (29.6) | 0.009* | 6.880 |
| Sore throat | 1 (0.6) | 5 (2.0) | 0.41 | – |
| Dyspnea | 5 (3.0) | 13 (5.1) | 0.28 | 1.179 |
| Tracheoesophageal fistula | 0 | 5 (2.0) | 0.16 | – |
| Number of hospitalizations within 12 months | 4.6±3.4 | 3.4±2.9 | <0.001* | – |
| Total number of hospitalizations | 5.1±4.2 | 4.0±3.7 | 0.001* | – |
| Average interval between hospitalizations within 12 months, months | 1.4±1.3 | 1.7±1.3 | 0.004* | – |
| Average hospitalization interval, months | 2.2±6.2 | 2.1±5.1 | 0.005* | – |
| Degree of airway stenosis (%) | ||||
| Preoperative | 66.70±20.16 | 65.41±20.46 | 0.48 | – |
| Postoperative | 31.86±12.29 | 32.27±14.06 | 0.41 | – |
| mMRC scores | ||||
| Preoperative | 2.41±0.70 | 2.40±0.71 | 0.90 | – |
| Postoperative | 0.98±0.80 | 1.08±0.90 | 0.34 | – |
| KPS scores | ||||
| Preoperative | 62.29±21.57 | 65.62±18.60 | 0.21 | – |
| Postoperative | 81.30±13.52 | 74.58±20.40 | 0.002* | – |
Continuous variables are expressed as mean ± standard deviation, while categorical variables are expressed as numbers (proportions). *, P<0.05. APC, argon plasma coagulation; KPS, Karnofsky Performance Status; mMRC, modified Medical Research Council; PITS, post-intubation tracheal stenosis; PTTS, post-tracheostomy tracheal stenosis.
The number of hospitalizations within 12 months was 4.6±3.4 times in the tracheal intubation group and 3.4±2.9 times in the tracheotomy group. There was a significant difference between the two groups (P<0.001). Average interval between hospitalizations within 12 months was 1.4±1.3 months in the tracheal intubation group and 1.7±1.3 months in the tracheotomy group, there was a significant difference between the two groups (P=0.004). After treatment, both groups showed a significant reduction in the degree of stenosis and mMRC scores, as well as a significant increase in KPS scores (P<0.001). The tracheostomy group had a higher postoperative KPS score compared to the intubation group (P=0.04), and there was no significant difference in the degree of stenosis (P=0.18) and mMRC scores (P=0.23) in both groups, as shown in Figure 4.
Figure 4.
Efficacy of bronchoscopic treatment. (A) Changes in the degree of stenosis before and after treatment; (B) changes in KPS before and after treatment; (C) changes in mMRC before and after treatment; (D) changes in the number of hospitalizations within 12 months and total hospitalizations; (E) changes in the duration of hospitalization intervals within 12 months and total hospitalization intervals; (F) comparison of the differences in the degree of stenosis, mMRC, and KPS scores before and after treatment between the intubation and tracheostomy groups. ns, no significance; **, P<0.01; *, P<0.05. KPS, Karnofsky Performance Status; mMRC, modified Medical Research Council; PITS, post-intubation tracheal stenosis; PTTS, post-tracheostomy tracheal stenosis.
Logistic regression analysis
We included the factors with P<0.05 in the above univariate analysis and important confounding factors in the logistic regression analysis, including age, gender, etiology, stenosis type, stenosis length, treatment method, and complications (bleeding). The logistic regression analysis shows that the stenosis length in the tracheotomy group is significantly longer than that in the tracheal intubation group (P<0.001). In terms of treatment methods, the tracheal intubation group may use balloon dilation (P=0.048) and laser under a rigid bronchoscope more frequently than the tracheotomy group (P=0.03). Regarding the stenosis type, dynamic stenosis may be more common in the tracheotomy group (P=0.01). In terms of etiology, patients with circulatory (P<0.001), respiratory (P=0.007), digestive (P=0.03), and poisoning problems (P=0.009) may be more inclined to choose tracheal intubation (P<0.05), while patients with nervous system problems and burns may be more inclined to choose tracheotomy (P=0.05), as shown in Figure 5.
Figure 5.
Multivariate logistic regression analysis. CI, confidence interval; KPS, Karnofsky Performance Status; mMRC, modified Medical Research Council; OR, odds ratio.
Discussion
In this study, there were differences in the clinical characteristics between PTTS and PITS, which was like foreign studies (15,20). In terms of primary diseases, univariate analysis shows that, drug poisoning and circulatory system causes were more common in the intubation group compared to the tracheostomy group; patients with neurological diseases accounted for a relatively large proportion among PTTS, and burn and scald patients were more common in the PTTS. The main reasons for these differences were the emergency measures under different conditions and the patients’ own states. For example, emergency intubation was likely to cause friction between the tip of the tube lumen and the tracheal wall, resulting in greater damage to the tracheal mucosa (20,21). Patients with neurological diseases needed tracheotomy to assist ventilation due to poor ability of spontaneous breathing or expectoration (22). Just as Richard et al. studied something similar, tracheostomy is required in 10% of patients with central nervous system (CNS) injury and can be as high as 50% to 70% in patients with a Glasgow Coma Scale <9 (23). Burn and scald patients often had inhalation injuries, causing damage to the trachea and lungs and reducing their resistance to infections, which inevitably led to the use of artificial airways and respiratory support, and burn patients have more severe scar contracture, serious airway stenosis, and obvious airflow limitation. It has been reported in some studies that the incidence of inhalation injury in burn patients after tracheotomy is as high as 5–23.5% (24,25). In the logistic regression analysis, in addition to drug poisoning and circulatory system diseases, respiratory and digestive systems were also more common in the intubation group. For example, previous studies have found that poor respiratory comfort is independently associated with intubation, and the intensity of dyspnea is a marker of the severity of acute respiratory failure (ARF), which was then considered for inclusion in the tracheal intubation decision (25,26). Digestive system diseases are generally caused by the need for general anesthesia surgery for some digestive tract diseases, during which tracheal intubation is used for assisted ventilation.
Univariate analysis of the narrow type shows that the scar type is more common in the tracheal intubation group, and dynamic stenosis is more likely to occur in the tracheotomy group. This is often because the stenosis caused by tracheal intubation is usually due to the high pressure and excessive volume on the endotracheal tube cuff, resulting in ischemic lesions and excessive scar hyperplasia to form fibrosis (27). PTTS usually means the formation of granulation tissue and scar contracture. At the same time, tracheal intubation at the stoma site may cause additional cartilage damage (28). This usually results in a longer length of tracheal stenosis, and similar results were obtained in this study. An important characteristic of scar is its high recurrence rate after simple resection, which is caused by changes in cell kinetics. There may be cell populations around the scar that are capable of regenerating abnormal tissue. Although recent data suggest that bronchoscopic methods play a key role in the treatment of benign tracheal stenosis, and indicate that after accurate classification of stenosis and careful patient selection, this treatment modality may be a definitive strategy in most cases (29). However, the stenosis may recur and repeated dilation may be required (30). This also explains why patients in both groups needed to be hospitalized repeatedly for bronchoscopic treatment. With continuous treatment, the interval between each follow-up visit gradually increased until they were judged to be cured if they did not need to be hospitalized within one year. The difference in the number of hospitalizations and the average interval between hospitalizations within 12 months for the two groups of patients may also be related to this.
The results of this study showed that granulation type was more common in PTTS, while scar type was more common in PITS. This was related to the different wound healing methods of the two groups. The wounds of endotracheal intubation were mostly simple scar contracture, which was related to the pressure necrosis caused by the cuff pressure on the tracheal wall cutting off the local blood flow (25). Tracheotomy was usually caused by the formation of excessive granulation tissue at the tracheostomy site accompanied by scar contracture (14). An important feature of scars was the high recurrence rate after simple excision, which was caused by changes in cell kinetics, and there might be cell populations around the scars that could regenerate abnormal tissues, which also explained why the number of treatments in PITS was higher and the hospitalization interval was shorter in this study (27).
In the choice of treatment methods, univariate analysis showed that balloon dilation, electrocautery, and laser under a rigid bronchoscope are more commonly used in the tracheal intubation group, while stent, snare, and T-tube are more commonly used in the tracheostomy group. Logistic regression analysis showed that balloon dilation and laser under rigid bronchoscope were statistically significant in the two groups. The choice of treatment method is often determined by the type of stenosis. Most cases in the tracheal intubation group develop scar stenosis. Generally, a high-frequency electrocautery knife or laser is first used to incise the scar, followed by balloon dilation to support the trachea, or cryotherapy is used to inhibit the accelerated healing response and reduce fibrosis (3). Research also shows that the combined use of laser and balloon dilation has a cure rate for scar stenosis between 60% and 95% (31). Mulry et al. also found in their research that compared with balloon dilation alone, high-frequency electrocautery combined with balloon dilation can prolong the interval between hospital readmissions of patients and reduce the number of times patients seek medical treatment again (32). In the tracheotomy group, granulation usually forms at the stoma site. Using a snare or cryotherapy to remove the granulation tissue often yields better results. For patients with dynamic collapse, stents or T-tubes are often used to support the trachea. Since PTTS is more likely to cause complex stenosis, it is more suitable for the placement of stents or T-tubes (28,33). In terms of complications, the bleeding probability of PTTS > PITS. This may indicate that the invasive nature of tracheotomy makes its bleeding risk significantly higher than that of tracheal intubation. However, no difference was found in the multivariate analysis.
In the comparison of the efficacy of treatment under bronchoscopy, both PITS and PTTS showed significant efficacy in the treatment under bronchoscopy, with the degree of tracheal stenosis reduced, the score of shortness of breath decreased, and the KPS score increased. This indicated that interventional bronchoscopy treatment was safe and effective for airway stenosis (34,35).
Shortcomings: (I) this study mainly focused on short-term efficacy and lacked an assessment of long-term prognosis. In the future, by tracking patients’ conditions for a long time, more comprehensive data support for long-term efficacy can be provided to optimize the endoscopic treatment plan. (II) The research on the pathophysiological mechanism of tracheal stenosis was insufficient, and recurrent airway stenosis remained a major challenge. Although interventional bronchoscopy treatment could significantly relieve airway obstruction, 40–70% of patients had postoperative airway restenosis (9). In the future, the causes of stenosis can be explored from the perspective of molecular biology, innovative treatment methods based on gene therapy and immunotherapy can be developed, or autologous cell transplantation can be used to promote airway re-epithelialization and inhibit recurrent granulation hyperplasia (36).
Conclusions
The clinical characteristics of patients with PITS and PTTS differ. Bronchoscopic treatment for PITS and PTTS shows significant effects, and the improvement in the tracheostomy group is more pronounced than that in the intubation group, indicating that bronchoscopic intervention can be considered as an alternative treatment option to surgery.
Supplementary
The article’s supplementary files as
Acknowledgments
None.
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 and its subsequent amendments. The study was approved by the Ethics Committees of Emergency General Hospital (No. K24-24) and Dongzhimen Hospital of Beijing University of Chinese Medicine (No. 2024DZMEC-039-01). Individual consent for this retrospective analysis was waived.
Footnotes
Reporting Checklist: The authors have completed the STROBE reporting checklist. Available at https://jtd.amegroups.com/article/view/10.21037/jtd-2024-2226/rc
Funding: This work was supported by the project of the Application of Photodynamic Therapy in Tumor Treatment (No. HX-DZM-202222).
Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://jtd.amegroups.com/article/view/10.21037/jtd-2024-2226/coif). The authors have no conflicts of interest to declare.
Data Sharing Statement
Available at https://jtd.amegroups.com/article/view/10.21037/jtd-2024-2226/dss
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