Application of EBUS-TBNAMore details
Endobronchial ultrasound transbronchial needle aspiration (EBUS-TBNA) is a reliable and commonly established technique, which can be perceived as the current gold standard that enables visualisation and sampling of mediastinal, central or hilar lesions and lymph nodes within the tracheo-bronchial tree. Cells of the tumour or lymph nodes are taken during the procedure. These can then be prepared as smears for diagnosis of malignancy and as cell blocks for histotyping. In selected cases EBUS-TBNA can also allow diagnosis of adenopathy.
Sedatives and topical pharyngeal anaesthesia are used for endobronchial ultrasonography. Where complete relaxation is desired, general anaesthesia may be recommended. Under general anaesthesia, a rigid tube, endotracheal tube or laryngeal mask is used to secure the airways and to facilitate bronchoscope insertion.
With the ultrasonic bronchoscope inserted into the trachea, the accessible lymph node station can be explored and lesions outlined. If available, Doppler examination of the target lesion, as well as the path of the needle, should be performed to avoid vessel puncture and reduce the risk of blood limiting the specimen’s quality for cytopathological analysis. The ultrasound image should be described exactly in terms of the location and orientation of the transducer and the characteristics of the lesion. The description should include location, size, shape, demarcation, echogenicity and relation to other lesions, organs and vessel structures. To outline the lesion and for full control during fine needle aspiration, the transducer must be in firm contact with the bronchial wall. The optional balloon allows better acoustic coupling of the transducer with the bronchial wall and in addition may reduce cough stimulus during the procedure due to its soft contact to the bronchial wall.
Lymph nodes staging (N-staging)
Patients with suspected lung cancer require reliable staging. EBUS-TBNA has proven to be of great value, especially in lymph node staging (N-staging). After examination of the relevant areas, the lesion to be sampled must be decided upon. As a rule the lymph node most distant to the tumour should be targeted first (=N3 node). After sampling of N-3 lymph nodes, the N-2 lymph nodes are examined. Then finally N-1 lymph nodes are sampled. By adhering to this rule, the risk of spreading malignant cells (to the central area or the side contralateral to the primary tumour) is avoided.
Olympus is unique in offering a 21G EBUS-TBNA needle in addition to the 22G needle. Both needles are equipped with a dimpled echogenic design that improves visibility on ultrasound images to enable a precise puncture. To ensure a safe procedure a fast locking mechanism prevents excessive protrusion of the needle and an additional safety mechanism stops the needle at 20mm if required.