Mediastinoscopy is a surgical technique that permits minimally invasive access to the mediastinum.1 In most cases, mediastinoscopy is used to biopsy and facilitate the histologic diagnosis of enlarged mediastinal lymph nodes (e.g., carcinoma, sarcoidosis, and tuberculosis) and masses (e.g., lymphoma, germ cell tumor, and thymoma). Mediastinoscopy currently plays a particularly important role in defining the clinical stage of bronchogenic carcinoma. Staging is the first step toward determining the optimal course of management. Staging directs treatment and implementation of protocols and permits comparison of treatment between patients.
Cervical mediastinoscopy, first described by Harken and colleagues,2 involves a neck incision that facilitates access to the superior mediastinum. Carlens3 and Pearson4 popularized a technique using a specially designed mediastinoscope through a suprasternal incision. Cervical mediastinoscopy, however, has limited access to the aorticopulmonary window. One approach to the aorticopulmonary window is “extended” cervical mediastinoscopy, a rarely used approach in which the mediastinoscope is inserted anterior to the aortic arch between the innominate artery and the left carotid artery.5 A more common approach to the aorticopulmonary window is through an anterior mediastinotomy—so-called anterior mediastinoscopy.6 Extended and anterior mediastinoscopy are techniques used to sample mediastinal lymph nodes in the aorticopulmonary window. In addition, anterior mediastinoscopy can be used in a variety of parasternal locations to facilitate the biopsy of anterior mediastinal masses to the right or left of midline. Subxiphoid mediastinoscopy is a technique in which the mediastinoscope is used to biopsy anterior masses in the lower mediastinum.
Frequent indications for mediastinoscopy include (1) staging patients with bronchogenic carcinoma7 and (2) obtaining tissue diagnoses in patients with unexplained adenopathy.8 Patients diagnosed with bronchogenic carcinoma are staged using a combination of modalities. CT scan of the chest determines the size and location of the primary tumor in conjunction with any associated lung parenchymal abnormalities (e.g., atelectasis, collapse, pneumonia, emphysema, or fibrosis). In addition, the location and size of enlarged mediastinal nodes direct further investigation to stage patients. Mediastinal nodes larger than 1 cm in their short axis are considered suspicious for tumor.
The differential diagnosis of patients with persistent and unexplained adenopathy includes sarcoidosis and lymphoma, but because these diseases may be difficult to distinguish clinically, histologic confirmation of the diagnosis usually is recommended. Sarcoidosis is characterized by noncaseating granulomas that can readily be distinguished from both Hodgkin and non-Hodgkin lymphomas.
Although cervical mediastinoscopy can be performed with low morbidity and mortality, the potential for catastrophic complications exists. Because of this risk, surgeons must be properly trained in mediastinoscopy. The procedure usually is performed as a day-surgery procedure, although it should be performed in a hospital setting because of the potential complications.
The procedure of mediastinoscopy involves a comprehensive examination of the mediastinum informed by CT scan findings. Sampling of the lymph nodes is directed by manual palpation and visual inspection (Fig. 132-1). Cervical mediastinoscopy can sample ipsilateral and ...