Pulmonary Medicine

Interventional Bronchoscopy: Transbronchial Needle Aspiration (TBNA)

General description of procedure, equipment, technique

Transbronchial Needle Aspiration (TBNA)

Initially defined in 1995 and subsequently described in European Respiratory Society (ERS) and American Thoracic Society (ATS) guidelines, interventional pulmonology is "the art and science of medicine as related to the performance of diagnostic and invasive therapeutic procedures that require additional training and expertise beyond that required in a standard pulmonary medicine training program." Clinical entities encompassed within the discipline include complex airway management, benign and malignant central airway obstruction, pleural diseases, and pulmonary vascular procedures.

Diagnostic and therapeutic procedures pertaining to these areas include rigid bronchoscopy, transbronchial needle aspiration, autofluorescence bronchoscopy, endobronchial ultrasound, transthoracic needle aspiration and biopsy, laser bronchoscopy, endobronchial electrosurgery, argon-plasma coagulation, cryotherapy, airway stent insertion, balloon bronchoplasty and dilatation techniques, endobronchial radiation (brachytherapy), photodynamic therapy, percutaneous dilatational tracheotomy, transtracheal oxygen catheter insertion, medical thoracoscopy, and image-guided thoracic interventions. This presentation focuses on transbronchial needle aspiration.

Needle aspiration of mediastinal lymph nodes was originally described in 1949. Contrast-enhanced computed tomography is performed prior to the procedure, and knowledge of the anatomic relationship of the tracheobronchial tree to lymph nodes and blood vessels is essential. In order to obtain an adequate specimen, the needle that is passed through the fiberoptic bronchoscope must reach the core of the lymph node while avoiding nearby vascular structures. TBNA of lymph nodes in the subcarinal and right paratracheal regions detects metastasis with a higher sensitivity than does TBNA of the left paratracheal lymph nodes.

An understanding the mediastinal anatomy is essential for safe performance of TBNA. To the right of the distal third of the trachea are the superior vena cava and azygos vein, and directly anterior to the trachea, above the level of the primary carina, lie the innominate artery and aortic arch. These major vessels cross the origin of the left main stem bronchus and lie anterior and to the left of the distal third of the trachea, making an easily recognizable pulsatile imprint.

The main pulmonary artery divides into the right and left branches within the concavity of the aortic arch. The left pulmonary artery runs antero-superiorly, in close approximation (within 3 to 5 mm) to the left mainstem bronchus; the right pulmonary artery lies anterior to the right mainstem bronchus and the origin of the upper lobe bronchus. The esophagus lies in close approximation (within 2 to 3 mm) of the posterior wall of the trachea and the left mainstem bronchus. Obviously, enlarged lymph nodes provide for better diagnostic yield.

A wide variety of biopsy needles are available. Retractable needles should be the only ones used, as needle-related damage to the bronchoscope's working channel is common and costly. The most commonly used needle is 22 gauge. While a larger,19-gauge needle is used for providing samples for histology, the system that encompasses the larger needle is cumbersome and has a poor record of performance.

Indications and patient selection

Needle aspiration has been utilized in diagnosis of endobronchial lesions, peripheral lung nodules, and mediastinal abnormalities (e.g., lymphadenopathy). The most common application of TBNA is in the diagnosis and staging of lung cancer.

Contraindications

There are no absolute contraindications to TBNA.

Details of how the procedure is performed

During insertion of the needle-containing catheter, the flexible bronchoscope is kept as straight as possible, with its distal tip in the neutral position, in order to prevent damage to the working channel, and the needle tip is retracted within the device's metal hub during its passage through the working channel. Then the catheter is retracted, and the tip of the needle is kept in view distal to the tip of the bronchoscope.

The bronchoscope is advanced as a single unit to the target area, and the tip of the needle is anchored in the intercartilaginous space prior to the needle's penetration of the airway wall. The needle is then inserted, with its metal hub against the tracheobronchial wall. Once the needle inserted, suction is applied at the proximal side port of the bronchoscope using a 60-ml syringe. The catheter is then agitated to and fro to obtain cytologic specimens during continuously applied suction. After suction is released, the needle is withdrawn from the target site.

The specimen for cytology is prepared using air from a 60-ml empty syringe to spray the specimen onto the slide, smearing it using another slide, and immediately placing it in a 95 percent alcohol solution. If a rapid, on-site evaluation (ROSE) service is available, real-time feedback from the cytologist helps to reduce the number of punctures required. Having a cytopathologist on-site to check for sample adequacy has been demonstrated to increase diagnostic yield. A trained assistant is also essential for procedure success and proper tissue handling.

Interpretation of results

A meta-analysis of forty-two studies of the accuracy of CT in detecting mediastinal nodes infiltrated with malignancy reported sensitivity and specificity of 79 percent and 78 percent, respectively. Another large meta-analysis of 113 studies found that the sensitivity and specificity of TBNA for the diagnosis of non-small cell lung cancer were 39 percent and 99 percent, respectively.

TBNA establishes the diagnosis and provides staging information in a single procedure. A positive N2 or N3 lymph node for non-small-cell lung cancer directs a nonsurgical approach to management. Positron emission tomography (PET) may be helpful in defining which lymph nodes should be sampled.

The utility of TBNA in the evaluation of lymphoma has been limited since the diagnosis usually requires larger samples of nodal tissue than TBNA can provide. However, the diagnosis of lymphoma may be established using a combination of cytology and flow cytometry. Several reports have confirmed an increase in the diagnostic yield when both transbronchial lung biopsies and TBNA are performed in patients with suspected sarcoidosis.

Performance characteristics of the procedure (applies only to diagnostic procedures)

Detailed data on performance characteristics are not available.

Outcomes (applies only to therapeutic procedures)

Not applicable.

Alternative and/or additional procedures to consider

Not applicable.

Complications and their management

Complications following TBNA are uncommon if appropriate precautions are taken and proper technique is employed. The most common complication is damage to the working channel of the bronchoscope. Infrequent complications include pneumothorax, pneumomediastinum, and hemomediastinum.

No firm recommendations have been provided regarding antibiotic prophylaxis. Oozing of a minimal amount of blood from the puncture site may be encountered.

What’s the evidence?

Baram, D, Garcia, RB, Richman, PS. "Impact of rapid on-site cytologic evaluation during transbronchial needle aspiration". Chest. vol. 128. 2005. pp. 869.

A report describing the utility of on-site cytologic review of specimens and highlighting the increase in yield and decrease in number of needle passes required.

Bilaceroglu, S, Perim, K, Gunel, O. "Combining transbronchial aspiration with endobronchial and transbronchial biopsy in sarcoidosis". Monaldi Arch Chest Dis. vol. 54. 1999. pp. 217.43.

A description of the utility of TBNA in the diagnosis of sarcoidosis and a comparison of the technique with endobronchial and transbronchial biopsies.

Holty, JE, Kuschner, WG, Gould, MK. "Accuracy of transbronchial needle aspiration for mediastinal staging of non-small cell lung cancer: a meta-analysis". Thorax. vol. 60. 2005. pp. 949.

A large meta-analysis on the diagnostic utility of TBNA.

Schieppati, E. "La puncion mediastinal a traves del espolon traqueal". Rev As Med Argent. vol. 663. 1949. pp. 497.

The original description of TBNA.

Shure, D, Fedullo, PF. "Transbronchial needle aspiration in the diagnosis of submucosal and peribronchial bronchogenic carcinoma". Chest. vol. 88. 1985. pp. 49.

An early report on the use of TBNA and diagnostic results.

Wang, KP, Marsh, BR, Summer, WR. "Transbronchial needle aspiration for diagnosis of lung cancer". Chest. vol. 80. 1981. pp. 48.

A classic paper on the early use of TBNA, including a description of the technique and its results.
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