Complete Medical “Mediastinoscopy” Under Conscious Sedation Using Combined Endoscopic Ultrasound and Endobronchial Ultrasound

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Background: Endoscopic ultrasound is effective in staging and FNA of lymph nodes in the posterior mediastinum but cannot visualize the anterior mediastinum. A prototype, small caliber linear array echoendoscope capable of real-time endobronchial ultrasound guided-FNA (Olympus Co., EBUS-FNA) has recently been developed to stage the anterior mediastinum. We hypothesized that combined EUS-EBUS-FNA would allow complete mediastinal staging in lung cancer patients and could be done safely under conscious sedation. Methods: Patients presenting with lung tumors and enlarged mediastinal lymph nodes underwent combined EUS-EBUS-FNA and bronchoscopy as indicated, all under a single conscious sedation with midazolam and meperidine. EBUS was performed by 2 pulmonologists. Three experience endosonographers performed EUS and assisted in the US interpretation of EBUS cases. Results: Twelve patients were found to have a total of 24 enlarged lymph nodes. EUS alone identified 8 (all lower mediastinum, celiac and AP window; 2 were malignant by FNA). EBUS alone identified 9 (5 pre-tracheal, 1 AP window, 3 hilar; 1 was malignant by FNA) and both procedures identified 8 (all subcarinal, 3 malignant by FNA by both procedures). EUS alone identified 1 enlarged (3 cm) adrenal gland (FNA: benign adenoma), 1 primary tumor (previous FNA positive by CT) and 1 pleural effusion (FNA negative). Bronchoscopy alone identified and FNA'd (negative) 1 tumor but no other lesions. Mean duration from sedation to completion of both procedures was 86 minutes (range 60-117) with mean sedation dose of midazolam, 8mg (5-10) and meperidine 116mg (15-175). No complications occurred. In 5 patients, the EUS examination was performed with both EBUS echoendoscope and the traditional (Olympus GF UCT130 or UCP130) echoendoscope. Both scopes were equally capable of imaging all posterior mediastinal lymph nodes, adrenal gland, celiac axis and left lobe of the liver. Conclusions: EUS and EBUS are highly complementary procedures which, in combination, appear to stage the entire mediastinum and relevant sub-diaphragmatic organs. The linear scanning EBUS scope is capable of performing both trans-esophageal and transbronchial ultrasound FNA, thus allowing single endoscope, single sedation mediastinal staging; a procedure that may be able to replace surgical staging of lung cancer.