Introduction
Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is a minimally invasive alternative to mediastinoscopy(An examination method for the mediastinum the area located behind the sternum in the center of the chest, between the two lungs.) that provides additional access to the lymph nodes, a better safety profile, and eliminates the costs and risks of theater time and general anesthesia with comparable sensitivity, although mediastinoscopy has a higher negative predictive value.
EBUS-TBNA also obtains larger samples than conventional TBNA, has better efficacy, and is safer during surgeries, as it permits sampling in real time under direct vision. Sonographic appearance and histological characteristics of lymph nodes may also have prognostic value. Consequently, EBUS-TBNA depicts cancer staging, diagnosis of lung cancer in the absence of an endobronchial lesion, and diagnosis of benign and malignant lesions. EBUS-TBNA is more expensive than conventional TBNA, but it can reduce the number of mediastinoscopies, which are more expensive. Future applications of endobronchial ultrasound may include airway disease and pulmonary vascular disease.
What Is Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration (EBUS-TBNA) Technique?
The utilization of endobronchial ultrasound-guided transbronchial fine needle aspiration (EBUS-TBNA) represents a unique and less invasive approach that incorporates real-time guidance for the purpose of sampling the masses surrounding the bronchi. A thorough knowledge of the technique, its indications, limitations, and potential diagnostic errors is necessary for cytopathologists, as these factors are crucial for the effective implementation of this technique.
What Are the Stages of the Technique?
The nodal staging of patients with non-small cell lung cancer (NSCLC) is the most significant application of this approach.
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The single most significant factor affecting resectability and prognosis in NSCLC, primary pulmonary cancers, is the nodal stage. Patients for definitive surgical treatment require cytological or histological evaluation of the mediastinum despite ongoing advancements in non-invasive nodal staging by computed tomography (CT), positron emission tomography (PET), and combination PET CT.
While transoesophageal EUS-FNA and EBUS-TBNA are two endoscopic minimally invasive sample methods that are increasingly used for this indication, mediastinoscopy remains the gold standard for the preoperative staging of NSCLC.
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Preoperative staging that is accurate reduces the number of unnecessary procedures done with the intention of curing the patient and permits the use of chemotherapy or chemo-radiation treatments followed by restaging and maybe surgery following downstaging.
What Are the Other Applications of EBUS?
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Identification of Infections - When tuberculous mediastinal lymphadenitis is the only problem, EBUS has a high diagnostic output. Histoplasmosis is rare outside of places where it is common or actions that put people at risk. Infectious agents can be found in laboratory samples with acute inflammation or granulomas by using special microorganism stains and microbiologic cultures.
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Peribronchial Visualization by EBUS- Patients with early Non-small cell lung cancer (NSCLC) who are unable to undergo surgery can use EBUS bronchoscopy to set limits for radiation. EBUS-placed fiducial marks in central and peripheral locations work well. EBS can help guide the placement of an airway tube and find and remove bronchogenic cysts in the mediastinum. EBUS-TBNA allows for excellent biopsies of the lung's tissue. As imaging and collection methods get better, this non-invasive way will be used in more situations.
What Are the Indications for Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration?
The primary indication for endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is typical:
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The process of evaluating the mediastinum for potential non-small cell lung cancer (NSCLC) is crucial in deciding both the prognosis and the appropriate course of treatment.
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In the case of diagnosing non-small cell lung cancer (NSCLC) and small cell lung cancer, it is common to encounter a lack of endoluminal tumor during bronchoscopy. This circumstance eliminates the necessity for a CT-guided lung biopsy or mediastinoscopy, particularly if the patient is not a suitable candidate for surgical intervention.
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To ascertain the cause of unexplained mediastinal lymphadenopathy that can be detected near the major airway, including benign illnesses like sarcoidosis or tuberculosis, a diagnostic approach is necessary.
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The utilization of tissue banking samples as a research tool for subsequent investigations.
What Are the Contraindications of the Procedure?
The EBUS-TBNA method is generally well tolerated; however, sampling from the mediastinal nodes should not be conducted on patients who are taking Warfarin or Clopidogrel medications or who are known to have coagulation or platelet function abnormalities due to the increased risk of bleeding in the mediastinum.
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After a myocardial infarction, EBUS-TBNA should be delayed for at least six weeks, and it should not be performed if there is continuing myocardial ischemia (a pathological condition characterized by the obstruction of blood flow to the myocardium, the heart muscle, due to the presence of plaques from atherosclerosis that partially or completely block a coronary artery. In the event of plaque breakdown, there is a potential for the occurrence of myocardial infarction, which is also known as a heart attack), arrhythmias (a medical disorder in which the heart's rhythm beats in a manner that is aberrant or irregular), or significant hypoxemia (a blood oxygen level that is abnormally low in comparison to normal levels) when the patient is at rest.
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There is a high probability of lymphoma; EBUS-TBNA is typically not a viable clinical choice.
What Is the Progression of the EBUS-TBNA?
The technique of endobronchial ultrasound (EBUS) exhibits potential for many applications in different disease processes.
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It is anticipated that the indications for EBUS will expand in the future as a result of a deeper understanding of the capabilities of this technology.
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The utilization of radial probe endobronchial ultrasound (EBUS) enables the acquisition of valuable data pertaining to the airway wall while also facilitating real-time imaging of the central pulmonary vasculature.
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The potential utility of endobronchial ultrasound (EBUS) in the identification of central pulmonary emboli has been assessed in cases where all pulmonary emboli had already been detected with earlier CT pulmonary angiography.
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They quantified the thickness of the airway wall and established a correlation between this measurement and the severity of asthma.
What Are the Applications of This Method?
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At present, mediastinoscopy is the method for evaluating the mediastinal stage when considering radical treatment.
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However, it provides evidence to support the use of endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) in staging subcentimeter nodes that are negative on computed tomography (CT) and positron emission tomography (PET).
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As evidence emerges, it is likely that EBUS-TBNA will become the preferred study for mediastinal staging. Therefore, it has the potential to serve as the principal method for staging in scenarios where subsequent staging is anticipated or as a viable alternative staging approach.
What Are the Limitations?
Regarding the limits that currently exist in the negative predictive ability of EBUS-TBNA, the utilization of mediastinoscopy is still required in situations in which EBUS-TBNA produces negative results for nodes. This is especially true in situations in which the initial probability of lung cancer is high.
Conclusion
EBUS-TBNA is an emerging technological advancement within the area of bronchoscopy. The main clinical indications for endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) include the staging of non-small cell lung cancer (NSCLC) and the diagnostic evaluation of mediastinal lymphadenopathy. EBUS-TBNA also has a diagnostic role in cases where benign diseases, such as sarcoidosis and tuberculosis, are suspected. The utilization of this approach as an initial sampling staging option in cases of suspected non-small cell lung cancer (NSCLC) with single hilar nodes, distinct N2 or N3 disease, or bulky mediastinal disease is considered less invasive.
