[66]. In the following decade, EUS-FNA has aided in the diagnosis and staging of mediastinal disease [67]. EUS is performed using an endoscope with an ultrasound transducer at the tip. There are two types of echoendoscopes, radial and curvilinear. The radial echoendoscope provides a 360-degree view while the curvilinear echoendoscope provides a 180-degree view. Through the esophageal wall, EUS can visualize stations 2L, 4L, 5, 7, 8, and 9. EUS can visualize and sample the left adrenal gland and liver lesions which aids in both diagnosis and complete staging [68]. The reported sensitivity, speci city, and accuracy were 81%, 100%, and 97%, respectively [69].

A meta-analysis was done in 2021 looking at EUS-FNA’s accuracy at diagnosing benign and malignant mediastinal and abdominal lymphadenopathy. The meta-analysis included twenty-six studies with 2753 patients with 2833 lymph nodes. EUS-FNA had a pooled sensitivity of 87% and a pooled speci city of 100% [70].

Combined EUS-FNA and EBUS-TBNA

EUS-FNA and EBUS-TBNA have a complimentary diagnostic yield and can allow for complete access to all nodal stations with EUS providing access to the posterior and inferior mediastinum (Stations 2L, 4L, 5, 7, 8, 9) and EBUS-TBNA providing access to the anterior/ superior mediastinum in conjunction with hilar lymph nodes (Stations 2R, 2L, 3P, 4R, 4L, 7, 10R, 10L, 11R, 11L). EUS can also provide sampling of the left adrenal gland and liver lesions. In a systematic review of seven studies including 811 patients, the pooled median sensitivity and speci city were 91% and 100%, respectively [12].

Case 2 Concluded

Patient underwent EBUS-TBNA with sampling of the hypermetabolic 10R lymph node that showed adenocarcinoma documenting Stage IIB. She

was referred to cardiothoracic surgery for consideration of surgical resection followed by adjuvant chemotherapy.

Case 3

A 63-year-old female with a past medical history of smoking in her 20s presented to clinic with an incidentally discovered RLL nodule. PET-CT showed uptake within the nodule and scattered hypermetabolic mediastinal and hilar lymph nodes (Fig. 28.8). She underwent a staged EBUS-­ TBNA and Robotic Navigational Bronchoscopy for diagnosis and staging. Biopsies were negative and she was referred to Cardiothoracic Surgery.

Tissue con rmation can be done endoscopically or surgically. When both modalities are available, current recommendations are to start with endoscopic techniques. If biopsy results are negative, the patient should undergo surgical staging of the mediastinum to con rm the diagnosis [71]. Available techniques include standard cervical mediastinoscopy (SCM), extended cervical mediastinoscopy (ECM), video-assisted thoracoscopic surgery (VATS) and anterior mediastinotomy (Chamberlain Procedure).

Standard Cervical Mediastinoscopy

The rst reported mediastinoscopy was done in 1959 by Carlens and was considered the gold standard for mediastinal nodal assessment for more than half a century. Cervical mediastinoscopy is the preferred technique for sampling stations 3, 2R, 2L, 4R, 4L, 7, 10R, 10L [71]. Nodal stations that cannot be reached using this modality include posterior 7, 8, 9, 5, and stations 11–14. During the procedure, a midline transverse incision is made immediately above the sternal notch. A mediastinoscope is inserted and follows the whole length of the trachea and bronchi allowing the exploration of the superior and middle mediastinum. The advantage of mediastinoscopy over minimally invasive needling techniques is direct visualization of the lymph node and the ability to

take large biopsies. This allows for more adequate samples for immunohistochemical staining, molecular analysis, and culture. The use of video techniques, videomediastinoscopy, has improved visualization, allows for the concurrent use of multiple surgical instruments, and allows for true mediastinal lymphadenectomy [72]. In a review of 9, 257 patients, the overall median sensitivity of standard cervical mediastinoscopy as compared to videomediastinoscopy and mediastinal lymphadenectomy was reported to be 78%, 89%, and 94%, respectively. The negative predictive value was 91%. The false negative cases were predominantly nodal stations that were not accessible by traditional mediastinoscopy and possibly affected by operator diligence in node dissection and sampling [12].

Extended Cervical Mediastinoscopy

Extended cervical mediastinoscopy was rst described by Specht in 1965 and allows for access to the sub aortic and para-aortic lymph nodes. It also allows for access to the same nodal stations as a standard cervical mediastinoscopy, stations 1, 2, 3, 4, 7, 10 ( [73], Fig. 28.7).

Historically, mediastinal staging would be accomplished by performing a standard cervical mediastinoscopy and a Chamberlain procedure, but ECM allows for access to the aortopulmonary window through the same incision made for the standard cervical mediastinoscopy without the surgical risk associated with a Chamberlain procedure.

Anterior Mediastinoscopy

Historically, the aortopulmonary window (station 5) and prevascular (station 6) have been difficult to gain access to and cannot be reached by minimally invasive techniques or standard cervical mediastinoscopy (Fig. 28.7). Lymphatic drainage to these lymph nodes usually involves the left upper lobe. McNeill and Chamberlain described the technique for gaining access to these lymph nodes in 1966. The procedure is performed by creating a left parasternal incision at the level of the second or third intercostal space and dissecting­ down to the lymph nodes for biopsy. It also allows for access to the left upper lobe tumors for simultaneous resection when there is no evidence of