Safety and effectiveness of microdebrider bronchoscopy for the management of central airway obstruction

Therapeutic bronchoscopy for malignant central airway obstruction: impact on quality of life and risk-benefit analysis

PURPOSE OF REVIEW

Malignant central airway obstruction (CAO) is a common complication in cancer and confers significant symptom burden and reduction in quality of life. Multiple bronchoscopic interventions exist for malignant CAO. In this review, we discuss the role of therapeutic bronchoscopy in the management of malignant CAO, emphasizing its impact on symptom control and quality of life while balancing the risks and benefits of intervention.

RECENT FINDINGS

Significant practice variations exist among practitioners of therapeutic bronchoscopy, and limited data exist to guide real-time clinical decision-making. Recent analyses demonstrate that therapeutic bronchoscopy is effective for symptoms associated with malignant CAO with infrequent complications. These studies also show that many of the improvements in symptoms and quality of life are sustained after intervention and are associated with improved overall survival in patients with malignant CAO. Recent data have also shown that the improvement in symptoms associated with therapeutic bronchoscopy may enable more definitive cancer treatment, further improving patient outcomes.

SUMMARY

Therapeutic bronchoscopy is safe and effective at improving patient-centered outcomes in malignant CAO. Research is ongoing to better understand its optimal role in this setting, refine decision-making regarding advanced bronchoscopic interventions, and further improve patient outcomes.

Nonmalignant Central Airway Obstruction: Options for Challenging Cases

Benign central airway obstruction is commonly referred as nonmalignant central airway obstruction (NMCAO). This is in part related to its lack of benign nature and significant life-quality impairment in patients. It is a pathologic entity with various etiologies and therefore a wide range of therapeutic options are available. Evidence regarding the optimal management that could provide a sustained restoration of airway patency is lacking. The lack of a common pathophysiologic pathway translating into a nonspecific symptom presenting as NMCAO has complicated treatment standardization and subsequently limited solid research to favor of one approach over another one. Our intent is to describe the limited evidence of the most utilized nonsurgical treatment for NMCAO as well as some upcoming promising therapeutic options such as mitomycin C injection, microdebrider, biodegradable stents, radiotherapy, Hybrid Knife, and endoluminal spray cryotherapy. Our goal with this manuscript is to motivate other authors to venture into prospective, multicenter, open-label trials aimed to describe long-term outcomes in patients with NMCAO.

Malignant Central Airway Obstruction: What's New?

Malignant central airway obstruction (MCAO) is a debilitating and life-limiting complication that occurs in an unfortunately large number of individuals with advanced intrathoracic cancer. Although the management of MCAO is multimodal and interdisciplinary, the task of providing patients with prompt palliation falls increasingly on the shoulders of interventional pulmonologists. While a variety of tools and techniques are available for the management of malignant obstructive lesions, advancements and evolution in this therapeutic venue have been somewhat sluggish and limited when compared with other branches of interventional pulmonary medicine (e.g., the early diagnosis of peripheral lung nodules). Indeed, one pragmatic, albeit somewhat uncharitable, reading of this article's title might suggest a wry smile and shug of the shoulders as to imply that relatively little has changed in recent years. That said, the spectrum of interventions for MCAO continues to expand, even if at a less impressive clip. Herein, we present on MCAO and its endoscopic and nonendoscopic management-that which is old, that which is new, and that which is still on the horizon.

Risk-score model to predict prognosis of malignant airway obstruction after interventional bronchoscopy

Background

Interventional bronchoscopy exhibits substantial effects for patients with malignant airway obstruction (MAO), while little information is available regarding the potential prognostic factors for these patients.

Methods

Between October 31, 2016, and July 31, 2019, a total of 150 patients undergoing interventional bronchoscopy and histologically-confirmed MAO were collected, in which 112 eligible participants formed the cohort for survival study. External validation cohort from another independent institution comprised 33 MAO patients with therapeutic bronchoscopy. The least absolute shrinkage and selection operator regression (LASSO) was applied to the model development dataset for selecting features correlated with MAO survival for inclusion in the Cox regression from which we elaborated the risk score system. A nomogram algorithm was also utilized.

Results

In our study, we observed a significant decline of stenosis rate after interventional bronchoscopy from 71.7%±2.1% to 36.6%±2.7% (P<0.001) and interventional bronchoscopy dilated airway effectively. Patients in our study undergoing interventional bronchoscopy had a median survival time of 614.000 days (95% CI: 269.876–958.124). Patients receiving distinct therapeutic methods of interventional bronchoscopy had different prognosis (P=0.022), and patients receiving treatment of electrocoagulation in combination with stenting and electrosurgical snare had worse survival than those receiving other options. Multivariate Cox analysis revealed that nonsmoking status, adenoid cystic carcinoma, and low preoperative stenosis length, as independent predictive factors for better overall survival (OS) of MAO patients. Then, the nomogram based on Cox regression and risk score system based on results from LASSO regression were elaborated respectively. Importantly, this risk score system was proved to have better performance than the nomogram and other single biomarkers such as traditional staging system (area under the curve 0.855 vs. 0.392–0.739). Survival curves showed that patients with the higher risk-score had poorer prognosis than those with lower risk-score (third quantile of OS: 126.000 days, 95% CI: 73.588–178.412 vs. 532.000 days, 95% CI: 0.000–1,110.372; P<0.001).

Conclusions

Nonsmoking status, adenoid cystic carcinoma, and low preoperative stenosis length, were independent predictive factors for better OS of MAO patients. We proposed a nomogram and risk score system for survival prediction of MAO patients undergoing interventional bronchoscopy with good performance.

Interventional Bronchoscopy

For over 150 years, bronchoscopy, especially flexible bronchoscopy, has been a mainstay for airway inspection, the diagnosis of airway lesions, therapeutic aspiration of airway secretions, and transbronchial biopsy to diagnose parenchymal lung disorders. Its utility for the diagnosis of peripheral pulmonary nodules and therapeutic treatments besides aspiration of airway secretions, however, has been limited. Challenges to the wider use of flexible bronchoscopy have included difficulty in navigating to the lung periphery, the avoidance of vasculature structures when performing diagnostic biopsies, and the ability to biopsy a lesion under direct visualization. The last 10-15 years have seen major advances in thoracic imaging, navigational platforms to direct the bronchoscopist to lung lesions, and the ability to visualize lesions during biopsy. Moreover, multiple new techniques have either become recently available or are currently being investigated to treat a broad range of airway and lung parenchymal diseases, such as asthma, emphysema, and chronic bronchitis, or to alleviate recurrent exacerbations. New bronchoscopic therapies are also being investigated to not only diagnose, but possibly treat, malignant peripheral lung nodules. As a result, flexible bronchoscopy is now able to provide a new and expanding armamentarium of diagnostic and therapeutic tools to treat patients with a variety of lung diseases. This State-of-the-Art review succinctly reviews these techniques and provides clinicians an organized approach to their role in the diagnosis and treatment of a range of lung diseases.

Palliative treatment of recurrent tracheal pleomorphic adenoma 10 years after segmental resection using the endobronchial shaver

OBJECTIVES

Thoracic surgeons often encounter patients with obstruction of the central airways requiring bronchoscopy to provide an open airway. The endobronchial shaver (Richard Wolf GmbH,Germany) is one of the new devices available for treatment of central airway obstruction. We report a tracheal tumor managed with this device.

METHODS

We report the successful use of endobronchial shaver via rigid bronchoscopy to resecte a complex stenosis 77-year-old male patient. Patient admitted to our clinic for progressive dyspnea and stridor. The patient's medical history was cervical collar incision with resection and anastomosis 10 years ago. A mass causing a obstruction of 70% of the tracheal lumen was detected with fiberoptic bronchoscopy. So, we decided to use endobronchial shaver for immediate effect.

RESULTS

Trachea was successfully recanalized with Endobronchial shaver (Richard Wolf GmbH, Germany). The patient was successfully extubated, and his dyspnea was resolved. Histopathologic examination of debris was revealed a tracheal pleomorphic adenoma. Postoperative course was uneventful and there was no evidence of recurrent or stenosis in 5 months of follow-up.

CONCLUSION

The Endobronchial shaver is an excellent instrument to manage intrluminal complex stenoses including tumor and granulation tissue with advantages including efficient removal of mass without a need for separate suctioning, coagulation,and limitation in oxygenation.

Anesthetic Management of the Narrowed Airway

Airway narrowing can be idiopathic or can occur as a result of airway tumors, hematomas, infections, and other pathologic conditions. Endoscopic management variously involves balloon dilatation, stent placement, laser vaporization of pathologic tissue, microdebridement, and other interventions, using either a rigid or a flexible bronchoscope. Jet ventilation is frequently used in such settings, especially when the presence of an endotracheal tube would interfere with the procedure. In desperate cases, extracorporeal membrane oxygenation may be used in managing the critical airway.

Postobstructive pneumonia in lung cancer

Postobstructive pneumonia can complicate lung cancer, particularly in more advanced stages of the disease, producing significant clinical decline and a poorer prognosis. It can lead to complications such as empyema, lung abscess and fistula formation. Postobstructive pneumonia can also be the first manifestation of an underlying malignancy. There are multiple challenges in the management of these patients. Recognition and treatment of this entity can be complex and includes the use of imaging, administration of broad-spectrum antibiotics to cover the wide variety of microorganisms involved and the use of different interventional modalities to relieve the obstruction. Existing literature on postobstructive pneumonia is scarce. In this article, we review the pathophysiology, different diagnostic methods and the therapeutic options to treat this condition. The utility and efficacy of the various modalities that are currently available in clinical practice to the interventional pulmonologist are described in some detail.

Bronchoscopic ablation techniques in the management of lung cancer

Central airway involvement is a common manifestation of lung cancer during the disease course. Some patients will require bronchoscopic therapeutic interventions to palliate symptoms, or less commonly to provide more definitive therapy of airway involvement. We describe an overview specifically of bronchoscopic ablative techniques that are available for use in malignant airway obstruction. Techniques that are more commonly used include bronchoscopic application of laser, electrocautery, argon plasma coagulation (APC), cryotherapy and mechanical debulking techniques. Less commonly employed are brachytherapy and photodynamic therapy. These techniques may be applied via flexible or rigid bronchoscopy depending upon the clinical scenario. The choice of technique depends on available tools and expertise, the urgency of the clinical scenario, and whether the lesion is predominately endobronchial, extrinsic compression, or a combination of both. Malignant airway obstruction is a common finding in lung cancer and there are a number of effective bronchoscopic ablative techniques that may be employed safely to palliate patients with a significant symptom burden.

A Concentric Tube Robot System for Rigid Bronchoscopy: A Feasibility Study on Central Airway Obstruction Removal

New robotic systems have recently emerged to assist with peripheral lung access, but a robotic system for rigid bronchoscopy has yet to be developed. We describe a new robotic system that can deliver thin robotic manipulators through the ports of standard rigid bronchoscopes. The manipulators bend and elongate to provide maneuverability of surgical tools at the endoscope tip, without endoscope motion. We describe an initial feasibility study on the use of this system to bronchoscopically treat a central airway obstruction (CAO). CAO is prevalent and can be life-threatening in patients with large tumors, and conventional rigid bronchoscopic treatments place patients at risk of complications including broken teeth, neck trauma and damage to oropharyngeal structures due to significant forces induced by bronchoscope tilting and manipulation. In this study, we used an ex vivo ovine airway model to demonstrate the ability of a physician using the robotic system to efficiently remove tissue and restore the airway. Pre- and post-operative CT scans showed that the robot was able to reduce the degree of airway obstruction stenosis from 75 to 14% on average for five CAO resections performed in an ex vivo animal model. Using cadaver experiments, we demonstrated the potential of the robotic system to substantially reduce the intraoperative forces applied to the patient's head and neck (from 80.6 to 4.1 N). These preliminary results illustrate that CAO removal is feasible with our new rigid bronchoscopy robot system, and that this approach has the potential to reduce forces applied to the patient due to bronchoscope angulation, and thereby reduce the risk of complications encountered during CAO surgery.

Advances in Interventional Pulmonology

Much has changed since the last review of interventional pulmonology (IP) published in this Clinics series. The rate of development of new techniques and their complexities require IP physicians to be constantly maintaining and updating their skill set. International agreed training pathways help ensure that the interventionalists of the present and future have the required knowledge of anatomy, manual dexterity, and clinical judgment to keep up with the continuing advances that are constantly expanding IP's diagnostic and therapeutic boundaries. IP remains one of the most desirable subspecialities in pulmonology, and the technologic advances make the future an exciting one.

Long-term quality-adjusted survival following therapeutic bronchoscopy for malignant central airway obstruction

Background

While therapeutic bronchoscopy has been used to treat malignant central (CAO) airway obstruction for >25 years, there are no studies quantifying the impact of therapeutic bronchoscopy on long-term quality-adjusted survival.

Methods

We conducted a prospective observational study of consecutive patients undergoing therapeutic bronchoscopy for CAO. Patients had follow-up at 1 week and monthly thereafter until death. Outcomes included technical success (ie, relief of anatomic obstruction), dyspnoea, health-related quality of life (HRQOL) and quality-adjusted survival.

Results

Therapeutic bronchoscopy was performed on 102 patients with malignant CAO. Partial or complete technical success was achieved in 90% of patients. At 7 days postbronchoscopy, dyspnoea improved (mean ∆Borg-day-7=−1.8, 95% CI −2.2 to −1.3, p<0.0001) and HRQOL improved (median prebronchoscopy 0.618 utiles, 25%–75% IQR 0.569 to 0.699, mean ∆utility-day-7+0.047 utiles, 95% CI +0.023 to 0.071, p=0.0002). Improvements in dyspnoea and HRQOL were maintained long-term. Compared with the prebronchoscopy baseline, HRQOL per day of life postbronchoscopy improved (mean ∆utility-long-term+0.036 utiles, 95% CI +0.014 to 0.057, p=0.002). Median quality-adjusted survival was 109 quality-adjusted life-days (QALDs) (95% CI 74 to 201 QALDs). Factors associated with longer quality-adjusted survival included better functional status, treatment-naïve tumour, endobronchial disease, less dyspnoea, shorter time from diagnosis to bronchoscopy, absence of cardiac disease, bronchoscopic dilation and receiving chemotherapy.

Conclusions

Therapeutic bronchoscopy improves HRQOL as compared with baseline, resulting in approximately a 5.8% improvement in HRQOL per day of life. The risk-benefit profile in these carefully selected patients was very favourable.

Trial registration number

Results; NCT03326570.

Interventional bronchoscopy in adults

INTRODUCTION

The field of interventional pulmonology (IP) is a rapidly maturing subspecialty of pulmonary medicine, which emphasizes advanced diagnostic and therapeutic bronchoscopy for the evaluation and management of central airway obstruction, mediastinal/hilar adenopathy and lung nodules/masses, as well as minimally invasive diagnostic and therapeutic pleural procedures. Areas covered: This review describes advances in diagnostic and therapeutic bronchoscopic techniques. Expert commentary: In the past decade, there has been a remarkable growth in available technology and equipment, as well as clinical and translational research efforts focused on patient-centered outcomes. Furthermore, the recent establishment of a uniform accreditation standard for all IP fellowship programs in the United States was an important step in the continued evolution of this subspecialty of pulmonary medicine.

Malignant central airway obstruction

This review comprehensively describes recent advances in the management of malignant central airway obstruction (CAO). Malignant CAO can be a dramatic and devastating manifestation of primary lung cancer or metastatic disease. A variety of diagnostic modalities are available to provide valuable information to plan a therapeutic intervention. Clinical heterogeneity in the presentation of malignant CAO provides opportunities to adapt and utilize endoscopic technology and tools in many ways. Mechanical debulking, thermal tools, cryotherapy and airway stents are methods and instruments used to rapidly restore airway patency. Delayed bronchoscopic methods, such as photodynamic therapy (PDT) and brachytherapy can also be utilized in specific non-emergent situations to establish airway patency. Although data regarding the success and complications of therapeutic interventions are retrospective and characterized by clinical and outcome measure variability, the symptoms of malignant CAO can often be successfully palliated. Assessment of risks and benefits of interventions in each individual patient during the decision-making process forms the critical foundation of the management of malignant CAO.

Techniques of endoscopic airway tumor treatment

Interventional bronchoscopy has a predominant role in the management of both early and advanced-stage airway tumors. Given the very poor prognosis of lung cancer, there is a need for new tools to improve early detection and bronchoscopic treatment of endo-bronchial precancerous lesions. In more advanced stages, interventional bronchoscopy plays an important role, as nearly a third of lung cancers lead to proximal airway obstruction. This will cause great discomfort or even life-threatening symptoms related to local extension, such as dyspnea, post-obstructive pneumonia, and hemoptysis. Surgery for very locally advanced disease is only effective for a limited number of patients and the effects of conventional antitumor therapies, like radiation therapy or chemotherapy, are inconstant and are too delayed in a palliative context. In this review, we aim to provide pulmonologists with an exhaustive technical overview of (I) the bronchoscopic management of benign endobronchial lesions; (II) the bronchoscopic management of malignant tumors, including the curative treatment of localized lesions and palliative management of malignant proximal airway stenosis; and (III) descriptions of the emerging endoscopic techniques used to treat peripheral lung tumors.

Integration of interventional bronchoscopy in the management of lung cancer

Tracheal or bronchial proximal stenoses occur as complications in 20-30% of lung cancers, resulting in a dramatic alteration in quality of life and poor prognosis. Bronchoscopic management of these obstructions is based on what are known as "thermal" techniques for intraluminal stenosis and/or placement of tracheal or bronchial prostheses for extrinsic compressions, leading to rapid symptom palliation in the vast majority of patients. This invasive treatment should only be used in cases of symptomatic obstructions and in the presence of viable bronchial tree and downstream parenchyma. This review aims to clarify 1) the available methods for assessing the characteristics of stenoses before treatment, 2) the various techniques available including their preferred indications, outcomes and complications, and 3) the integration of interventional bronchoscopy in the multidisciplinary management of proximal bronchial cancers and its synergistic effects with the other specific treatments (surgery, radiotherapy or chemotherapy).

Operative endoscopy of the airway

Airway endoscopy has long been an important and useful tool in the management of thoracic diseases. As thoracic specialists have gained experience with both flexible and rigid bronchoscopic techniques, the technology has continued to evolve so that bronchoscopy is currently the foundation for diagnosis and treatment of many thoracic ailments. Airway endoscopy plays a significant role in the biopsy of tumors within the airways, mediastinum, and lung parenchyma. Endoscopic methods have been developed to treat benign and malignant airway stenoses and tracheomalacia. And more recently, techniques have been conceived to treat end-stage emphysema and prolonged air leaks in select patients. This review describes the abundant uses of airway endoscopy, as well as technical considerations and limitations of the current technologies.

Complications Following Therapeutic Bronchoscopy for Malignant Central Airway Obstruction: Results of the AQuIRE Registry

BACKGROUND

There are significant variations in how therapeutic bronchoscopy for malignant airway obstruction is performed. Relatively few studies have compared how these approaches affect the incidence of complications.

METHODS

We used the American College of Chest Physicians (CHEST) Quality Improvement Registry, Evaluation, and Education (AQuIRE) program registry to conduct a multicenter study of patients undergoing therapeutic bronchoscopy for malignant central airway obstruction. The primary outcome was the incidence of complications. Secondary outcomes were incidence of bleeding, hypoxemia, respiratory failure, adverse events, escalation in level of care, and 30-day mortality.

RESULTS

Fifteen centers performed 1,115 procedures on 947 patients. There were significant differences among centers in the type of anesthesia (moderate vs deep or general anesthesia, P < .001), use of rigid bronchoscopy (P < .001), type of ventilation (jet vs volume cycled, P < .001), and frequency of stent use (P < .001). The overall complication rate was 3.9%, but significant variation was found among centers (range, 0.9%-11.7%; P = .002). Risk factors for complications were urgent and emergent procedures, American Society of Anesthesiologists (ASA) score > 3, redo therapeutic bronchoscopy, and moderate sedation. The 30-day mortality was 14.8%; mortality varied among centers (range, 7.7%-20.2%, P = .02). Risk factors for 30-day mortality included Zubrod score > 1, ASA score > 3, intrinsic or mixed obstruction, and stent placement.

CONCLUSIONS

Use of moderate sedation and stents varies significantly among centers. These factors are associated with increased complications and 30-day mortality, respectively.

Therapeutic bronchoscopy for malignant central airway obstruction: success rates and impact on dyspnea and quality of life

BACKGROUND

There is significant variation between physicians in terms of how they perform therapeutic bronchoscopy, but there are few data on whether these differences impact effectiveness.

METHODS

This was a multicenter registry study of patients undergoing therapeutic bronchoscopy for malignant central airway obstruction. The primary outcome was technical success, defined as reopening the airway lumen to > 50% of normal. Secondary outcomes were dyspnea as measured by the Borg score and health-related quality of life (HRQOL) as measured by the SF-6D.

RESULTS

Fifteen centers performed 1,115 procedures on 947 patients. Technical success was achieved in 93% of procedures. Center success rates ranged from 90% to 98% (P = .02). Endobronchial obstruction and stent placement were associated with success, whereas American Society of Anesthesiology (ASA) score > 3, renal failure, primary lung cancer, left mainstem disease, and tracheoesophageal fistula were associated with failure. Clinically significant improvements in dyspnea occurred in 90 of 187 patients measured (48%). Greater baseline dyspnea was associated with greater improvements in dyspnea, whereas smoking, having multiple cancers, and lobar obstruction were associated with smaller improvements. Clinically significant improvements in HRQOL occurred in 76 of 183 patients measured (42%). Greater baseline dyspnea was associated with greater improvements in HRQOL, and lobar obstruction was associated with smaller improvements.

CONCLUSIONS

Technical success rates were high overall, with the highest success rates associated with stent placement and endobronchial obstruction. Therapeutic bronchoscopy should not be withheld from patients based solely on an assessment of risk, since patients with the most dyspnea and lowest functional status benefitted the most.

Endotracheal Tube Management and Obstructed Airway

Thoracic surgery encompasses a wide array of surgical techniques, most of which require lung isolation for surgical exposure in the pleural cavity; this, in turn, demands an extensive knowledge of respiratory mechanics and modalities of airway control. Likewise, effective treatment of an acute central airway obstruction calls for a systematic approach using clear communication between teams and a comprehensive knowledge of available therapeutic modalities by the surgeon.

Successful treatment of bronchial obstruction by flexible bronchoscopy and isoniazid: A case report

Interventional bronchology techniques have been employed as an effective first-line treatment in patients with tracheobronchial obstruction. However, recurrent stenosis produced by granulation tissue requires repeated procedures. Previous studies have indicated that isoniazid regulates collagen deposition and decreases collagen content. Thus, isoniazid has been successfully administered to patients with lesions who exhibited a delay in the healing process. A case of a left mainstem obstruction managed by interventional bronchology is described in the present study. Repeated bronchial stenosis was observed even following numerous treatment procedures, however, administration of isoniazid resulted in the inhibition of hypertrophic scar formation and prevention of repeated stenosis. The suppressive effect of isoniazid on granulation formation and further observations are reported. Few studies have been conducted with regard to the function of isoniazid in suppressing scar hyperplasia, therefore, the mechanism requires further investigation.