Advertisement

Endobronchial Ultrasound

  • Traves D. Crabtree
    Correspondence
    Address reprint requests to Traves D. Crabtree, MD, Assistant Professor of Surgery, Cardiothoracic Surgery, Washington University School of Medicine, Barnes-Jewish Hospital, 660 South Euclid Avenue, Campus Box 8234, Saint Louis, MO 63110
    Affiliations
    Washington University School of Medicine, Barnes-Jewish Hospital, Saint Louis, Missouri
    Search for articles by this author
      The gold standard for mediastinal lymph node staging is mediastinoscopy. Standard mediastinoscopy or video mediastinoscopy provides access to levels 2R, 2L, 7, 4R, 4L, and 10 lymph nodes. Standard mediastinoscopy helps confirm the presence of malignant disease in clinically suspicious lymph nodes and is reliable for diagnosing occult microscopic disease for the adequate staging of lung cancer. Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) has provided an alternative to mediastinoscopy for the biopsy of mediastinal lymph nodes in select clinical situations as well as provided access to more peripheral nodes and nodules that mediastinoscopy cannot access.
      Mediastinoscopy is considered a very safe procedure with a reported operative mortality of 0.05 to 0.2% in a large series of patients with a complication rate of 0.56 to 1.07%.
      • Hammoud Z.T.
      • Anderson R.C.
      • Meyers B.F.
      • et al.
      The current role of mediastinoscopy in the evaluation of thoracic disease.
      • Lemaire A.
      • Nikolic I.
      • Petersen T.
      • et al.
      Nine-year single center experience with cervical mediastinoscopy: Complications and false negative rate.
      Reported complications include hemorrhage, vocal cord injury, tracheal injury, and pneumothorax. A large series of EBUS-TBNA have reported no mortality and almost no morbidity associated with the procedure.
      • Sarkiss M.
      • Kennedy M.
      • Riedel B.
      • et al.
      Anesthesia technique for endobronchial ultrasound-guided fine needle aspiration of mediastinal lymph node.
      • Vincent B.D.
      • El-Bayoumi E.
      • Hoffman B.
      • et al.
      Real-time endobronchial ultrasound-guided transbronchial lymph node aspiration.
      • Yasufuku K.
      • Chiyo M.
      • Koh E.
      • et al.
      Endobronchial ultrasound guided transbronchial needle aspiration for staging of lung cancer.
      Furthermore, preliminary studies have reported sensitivity of EBUS-TBNA in identifying nodal metastases in the setting of lung cancer ranging from 90 to 98%, depending on the population studied.
      • Vincent B.D.
      • El-Bayoumi E.
      • Hoffman B.
      • et al.
      Real-time endobronchial ultrasound-guided transbronchial lymph node aspiration.
      • Yasufuku K.
      • Chiyo M.
      • Koh E.
      • et al.
      Endobronchial ultrasound guided transbronchial needle aspiration for staging of lung cancer.
      • Wallace M.B.
      • Pascual J.M.
      • Raimondo M.
      • et al.
      Minimally invasive endoscopic staging of suspected lung cancer.
      • Lee H.S.
      • Lee G.K.
      • Lee H.
      • et al.
      Real-time endobronchial ultrasound-guided transbronchial needle aspiration in mediastinal staging of non-small cell lung cancer: How many aspirations per target lymph node station?.

      Anesthesia

      Several options are available for anesthesia during EBUS. Conscious sedation with short-acting agents such as fentanyl and midazolam may be utilized in an ambulatory setting to perform EBUS. Given the larger size of the EBUS videobronchoscope, it is generally passed transorally rather than via the standard transnasal approach. Predominant intravenous anesthesia with propofol and fentanyl can also be utilized in concert with a laryngeal mask airway device for adequate control of the airway. The tip of the scope can comfortably fit through a no. 4 laryngeal mask. The procedure can also safely be performed under general anesthesia using a no. 8.5 or larger endotracheal tube. The videobronchoscope can fit through a no. 8 endotracheal tube as well but a larger tube allows for better ventilation. The laryngeal mask airway does provide the advantage of allowing for visualization of the entire paratracheal area. If using an endotracheal tube, the tube may need to be withdrawn to a point near the vocal cords to allow for ultrasound visualization of the high paratracheal lymph nodes. We typically prefer general anesthesia given the time required to perform multiple biopsies at multiple different nodal stations. Bronchoscopy is performed with a conventional flexible bronchoscope before EBUS to adequately assess the airway for intrabronchial tumor, mucosal abnormalities, and endotracheal tube positioning in the proximal trachea.
      During the procedure, a cytopathology technician is present in the operating room to help prepare the slides. An on-site cytopathologist greatly facilitates the process by allowing for immediate assessment of the adequacy of and diagnostic evaluation of the specimen. This is of critical importance if EBUS-TBNA is to be utilized to make intraoperative decisions as is currently done with mediastinoscopy. The presence of lymph tissue is often considered an adequate specimen.

      Operative Technique

      Figure thumbnail gr1
      Figure 1The linear array ultrasonic bronchoscope (Olympus XBF-UC 160F) with the biopsy sheath deployed. The outer diameter of the EBUS scope is 6.7 mm and 6.9 mm at the tip. The optical system in this scope provides an 80-degree field of view at a 35-degree forward oblique angle. The EBUS scope provides monocolor Doppler flow mapping for identification of blood vessels. (Color version of figure is available online at http://www.optechtcs.com.)
      Figure thumbnail gr2
      Figure 2Mediastinal and hilar lymph nodes. (A) Highlighted nodes are typically accessible by standard cervical video mediastinoscopy. (B) Highlighted nodes are typically accessible by EBUS-TBNA. a. = artery; Ao = aorta; PA = pulmonary artery; pulm lig = pulmonary ligament; v. = vein.
      Figure thumbnail gr3
      Figure 3EBUS-TBNA of subcarinal (station 7) lymph nodes. (A) The EBUS scope can be positioned in either the proximal right mainstem bronchus (as depicted) or the proximal left mainstem bronchus. (B) The scope is positioned in the right mainstem bronchus with the balloon inflated. Pulling the scope back allows for visualization of the contralateral mainstem bronchus at the level of the carina. This provides a visual landmark when examining the subcarinal space. Ultrasound and Doppler identification of the right and left pulmonary artery also allows for orientation regarding the anterior portion of the respective mainstem bronchus. EBUS = endobronchial ultrasound.
      Figure thumbnail gr4
      Figure 4(A) Scope positioning for biopsy of a right paratracheal (station 4R) lymph node. (B) Lymph nodes are typically rounded with well-demarcated borders as depicted above. The needle is barbed to allow for ultrasound visualization. (C) Standard ultrasound images can typically identify even small bronchial arteries adjacent to lymph nodes. Color Doppler can also be performed to confirm blood flow through these vessels. a. = artery; EBUS = endobronchial ultrasound.
      Figure thumbnail gr5
      Figure 5(A) Scope positioning for biopsy of a left paratracheal (station 4L) lymph node. (B) Biopsy of a 5- to 6-mm station 4L lymph node positioned between the aortic arch and the left main pulmonary artery. The needle is deployed within the node. Marks adjacent to the image indicate centimeters for calibration of nodal size in planning the depth of needle insertion. EBUS = endobronchial ultrasound; PA = pulmonary artery.
      Figure thumbnail gr6
      Figure 6N1 nodal stations can also be accessed by EBUS. Positioning of the scope in the bronchus intermedius allows for visualization of 11R lymph nodes most commonly identified at the junction of the right upper lobe and the bronchus intermedius. Visualization of the carina between the right upper lobe orifice and bronchus intermedius allows for proper orientation of the videobronchoscope for ultrasound identification of these lymph nodes. The EBUS videobronchoscope can also be utilized to biopsy tumors adjacent to a segmental bronchus. It is often not necessary to inflate the balloon of the scope while performing ultrasound in the segmental bronchi. EBUS = endobronchial ultrasound.
      Figure thumbnail gr7
      Figure 7Transbronchial needle aspiration device attached to the working port of the EBUS videobronchoscope. The syringe attached is utilized to inflate the ultrasound balloon sheath with saline. A locking device at the base of the apparatus secures the device to the working port of the scope. (Color version of figure is available online at http://www.optechtcs.com.)
      Figure thumbnail gr8
      Figure 8(A) Once the node has been identified by ultrasound, the disposable needle aspiration device is secured to the working port of the scope with the fastening device. It is important to hold the scope steady, maintaining nodal visualization while the device is secured in place. This can be done by the bronchoscopist or by an assistant while the bronchoscopist steadies the scope. Once secured, the protective sheath must be deployed by loosening the screw and advancing the shaft of the sheath. The 22-gauge needle remains within the sheath at this time. When deployed, the sheath must be well out of the working channel of the bronchoscope (B) and be clearly visible in the field of view of the bronchoscope (C) to avoid needle injury to the inner channel of the scope. EBUS = endobronchial ultrasound.
      Figure thumbnail gr9
      Figure 9Once the sheath is in position, the depth of needle insertion can be set based on ultrasound assessment by adjusting the gray needle guard. (A) Demonstrates the needle guard set for a depth of 2 cm. This can be set to a depth of up to 4 cm, although this is rarely necessary. The small gray clip must be removed if one desires a depth >2 cm. Once positioned, the screw of the needle guard is secured and the needle is ready to be engaged.
      Once the needle guard is secured, the needle is advanced with the stylet in place (B), deploying the needle out of the sheath (C). This requires a sharp jab rather than a slow movement to allow for penetration through the bronchial wall. The videobronchoscope should be held steady to maintain visualization of the node during needle insertion.
      The stylet prevents contamination of the needle with bronchial epithelial cells and cartilage during passage of the needle into the lymph node. Elderly patients with calcified tracheal cartilage make passage of the needle difficult at times. Making slight adjustments to the position of the bronchoscope while maintaining visualization of the lymph node to avoid penetration of the tracheal ring may be necessary. This is more pertinent when performing biopsies of the paratracheal and pretracheal lymph nodes.
      Figure thumbnail gr10
      Figure 10Once the needle has been deployed into the lymph node, the stylet is removed from the device and exchanged for a vacuum lock syringe. With the needle visible in the node, the vacuum is applied to the needle via the stopcock. If blood is aspirated, the needle is withdrawn and the position of the scope is adjusted. The needle is then agitated 6 to 10 times in the node with direct ultrasound visualization. Before retracting the needle from the lymph node, the vacuum is turned off. The needle is then retracted back into the sheath and the entire device is removed from the scope to develop the slides for analysis. Multiple aspirations per node increases the diagnostic yield and accuracy of EBUS-TBNA.

      Comments

      In a prospective study of EBUS-TBNA for mediastinal staging of lung cancer, the diagnostic accuracy rate was 96.3% in correctly predicting lymph node stage in 105 patients.
      • Yasufuku K.
      • Chiyo M.
      • Koh E.
      • et al.
      Endobronchial ultrasound guided transbronchial needle aspiration for staging of lung cancer.
      In this study, EBUS-TBNA prevented the need for mediastinoscopy in 29 patients, thoracotomy in 8 patients, and video-assisted thoracoscopic surgery in 4 patients. A direct comparison of EBUS-TBNA, computed tomography (CT), and positron emission tomography (PET) was performed in 102 patients undergoing planned resection for lung cancer. The sensitivity of CT, PET, and EBUS-TBNA for the correct diagnosis of mediastinal and hilar lymph node staging was 76.9, 80.0, and 92.3%, respectively. The diagnostic accuracy was 60.8, 72.5, and 98%, respectively.
      • Yasufuku K.
      • Nakajima T.
      • Motoori K.
      • et al.
      Comparison of endobronchial ultrasound, positron emission tomography, and CT for lymph node staging of lung cancer.
      The combined use of EBUS-TBNA and endoscopic ultrasound may improve the yield compared with EBUS-TBNA alone by providing additional access to level 8 and 9 station lymph nodes.
      • Wallace M.B.
      • Pascual J.M.
      • Raimondo M.
      • et al.
      Minimally invasive endoscopic staging of suspected lung cancer.
      Currently, data are limited comparing mediastinoscopy and EBUS-TBNA for mediastinal lymph node staging of lung cancer.
      • Ernst A.
      • Anantham D.
      • Eberhardt R.
      • et al.
      Diagnosis of mediastinal adenopathy-real-time endobronchial ultrasound guided needle aspiration versus mediastinoscopy.
      In general, the higher sensitivities and accuracy reported in series of patients undergoing EBUS-TBNA may be attributed to a greater number of patients with suspicious lymph nodes by CT or PET rather than identifying occult lymph node metastases in patients with a negative PET and CT. To date, there have been no reported major complications related to EBUS-TBNA.
      Over the past 18 months, we have performed 200 EBUS-TBNA procedures at our center in patients with mediastinal adenopathy. In a cross-section of patients with mediastinal adenopathy undergoing EBUS-TBNA, 64.8% had a confirmed diagnosis of malignancy, 7.6% had a diagnosis of granulomatous disease, 19% had benign lymphoid tissue, whereas 6.7% of the biopsies were nondiagnostic. We have had no complications as a result of the EBUS procedure or the anesthesia.
      It is likely that EBUS-TBNA may prevent the need for mediastinoscopy in some patients with positive results by EBUS. The greatest concern, however, is the clinical significance of a negative TBNA by EBUS when staging lung cancer. The presence of micrometastatic disease in normal-sized lymph nodes may be more likely to be missed by FNA biopsy compared with mediastinoscopy. This issue should be considered when choosing to utilize EBUS instead of mediastinoscopy for routine staging.
      EBUS can also be utilized for diagnosing other causes of mediastinal adenopathy. The presence of granulomas in needle biopsy specimens can assist in the diagnosis of granulomatous disease. Separate biopsies should be performed simultaneously for culture. Utilization of EBUS for the diagnosis of suspected lymphoma requires multiple needle biopsies of the affected nodes to provide enough cellular tissue for flow cytometric analysis. This reemphasizes the importance of having an on-site cytopathologist to assist with assessing the adequacy of the specimen.
      Other clinical situations favor the utilization of EBUS-TBNA. When used in conjunction with mediastinoscopy, EBUS-TBNA can be useful in the staging and restaging of patients undergoing induction therapy for lung cancer. EBUS-TBNA may be utilized as the initial procedure followed by mediastinoscopy after induction therapy or vice versa. We have also used EBUS-TBNA in the setting of superior vena cava syndrome where mediastinoscopy can be hazardous or in patients who have undergone extensive neck dissections for head and neck tumors, limiting neck mobility and accessibility necessary for mediastinoscopy. In addition to the aforementioned benefits of linear EBUS-TBNA, radial EBUS-TBNA has also been shown to improve the diagnostic yield of biopsy of parenchymal nodules compared with standard bronchoscopy with fluoroscopy.
      • Chao T.Y.
      • Chien M.T.
      • Lie C.H.
      • et al.
      Endobronchial ultrasound-guided transbronchial needle aspiration increases the diagnostic yield of peripheral pulmonary lesions: A randomized trial.
      Radial endobronchial ultrasound is an ultrasound probe surrounded by a saline-filled balloon that fits through the working channel of a regular size bronchoscope. This allows for ultrasound localization of tumors that cannot be visualized intrabronchially with standard video bronchoscopy. The ultrasound allows for localization of these tumors to a specific bronchus for subsequent biopsy. The biopsy is not performed in real-time with ultrasound as the radial probe only allows for localization. It must then be removed for standard biopsy techniques, unlike the linear EBUS scope.
      Regarding coding and billing for EBUS-TBNA, the current procedural terminology (CPT) code for bronchoscopy with TBNA is 31629. The national average physician fee for this code is $191.96 in a physician facility and $643.67 in a nonphysician facility. The physician fee for TBNA for each additional nodal station (CPT 31633) is $63.61 in a physician facility and $86.46 in a nonphysician facility. Additionally, the physician fee for EBUS (CPT 31620) is $67.79 in a physician facility and $273.08 in a nonphysician facility. As an example, a standard bronchoscopy with EBUS biopsy of three nodal stations would be billed as bronchoscopy with biopsy ($195.69 for first nodal station), EBUS ($68.19), and for each additional separate nodal station biopsy ($65.23 × 2) for a total of $394.34. Standard bronchoscopy combined with EBUS-TBNA of one nodal station generally requires approximately 10 to 20 minutes to perform with an additional 5 to 10 minutes/nodal station.

      Conclusions

      EBUS-TBNA is an emerging technology that is a useful adjunct in the evaluation of patients with or without lung cancer with mediastinal adenopathy. The reported accuracy to date in select patients is favorable, although the role of EBUS in routine staging of lung cancer remains undetermined. Mediastinoscopy remains the gold standard for staging of lung cancer when performed with very low morbidity in experienced hands. It is essential that thoracic surgeons play a role in the application of EBUS for the biopsy of mediastinal lymph nodes to maintain the same standard for lymph node biopsy that mediastinoscopy has afforded.

      References

        • Hammoud Z.T.
        • Anderson R.C.
        • Meyers B.F.
        • et al.
        The current role of mediastinoscopy in the evaluation of thoracic disease.
        J Thorac Cardiovasc Surg. 1999; 118: 894-899
        • Lemaire A.
        • Nikolic I.
        • Petersen T.
        • et al.
        Nine-year single center experience with cervical mediastinoscopy: Complications and false negative rate.
        Ann Thorac Surg. 2006; 82: 1185-1189
        • Sarkiss M.
        • Kennedy M.
        • Riedel B.
        • et al.
        Anesthesia technique for endobronchial ultrasound-guided fine needle aspiration of mediastinal lymph node.
        J Cardiothorac Vasc Anesth. 2007; 21: 892-896
        • Vincent B.D.
        • El-Bayoumi E.
        • Hoffman B.
        • et al.
        Real-time endobronchial ultrasound-guided transbronchial lymph node aspiration.
        Ann Thorac Surg. 2008; 85: 224-230
        • Yasufuku K.
        • Chiyo M.
        • Koh E.
        • et al.
        Endobronchial ultrasound guided transbronchial needle aspiration for staging of lung cancer.
        Lung Cancer. 2005; 50: 347-354
        • Wallace M.B.
        • Pascual J.M.
        • Raimondo M.
        • et al.
        Minimally invasive endoscopic staging of suspected lung cancer.
        JAMA. 2008; 299: 540-546
        • Lee H.S.
        • Lee G.K.
        • Lee H.
        • et al.
        Real-time endobronchial ultrasound-guided transbronchial needle aspiration in mediastinal staging of non-small cell lung cancer: How many aspirations per target lymph node station?.
        Chest. 2008; 134: 368-374
        • Yasufuku K.
        • Nakajima T.
        • Motoori K.
        • et al.
        Comparison of endobronchial ultrasound, positron emission tomography, and CT for lymph node staging of lung cancer.
        Chest. 2006; 130: 710-718
        • Ernst A.
        • Anantham D.
        • Eberhardt R.
        • et al.
        Diagnosis of mediastinal adenopathy-real-time endobronchial ultrasound guided needle aspiration versus mediastinoscopy.
        J Thorac Oncol. 2008; 3: 577-582
        • Chao T.Y.
        • Chien M.T.
        • Lie C.H.
        • et al.
        Endobronchial ultrasound-guided transbronchial needle aspiration increases the diagnostic yield of peripheral pulmonary lesions: A randomized trial.
        Chest. 2008; (Sep 23 (Epub ahead of print))
      1. (Accessed August 1, 2008)