Chapter 157: Cervical Mediastinoscopy and Anterior Mediastinotomy

INTRODUCTION

Mediastinoscopy is a surgical technique that permits minimally invasive access to the mediastinum.¹ Frequently, mediastinoscopy is used to biopsy and facilitate the histologic diagnosis of enlarged mediastinal lymph nodes (carcinoma, sarcoidosis, and tuberculosis) and masses (lymphoma, germ cell tumor, and thymoma). Mediastinoscopy plays an important role in staging of bronchogenic carcinoma. Staging directs treatment, guides implementation of protocols, and permits comparison of treatment between patients.

Cervicomediastinal exploration, first described by Harken,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 small suprasternal incision. Lerut⁵ introduced the idea of video mediastinoscopy 1989, wherein videoscopic technology is merged with a standard mediastinoscope. Video mediastinoscopy allows conduct and visualization of the procedure under magnification with the image projected onto a large screen thus facilitating teaching and allowing all operating personnel to observe the conduct of the operation. The comments in the rest of this chapter pertain to both standard mediastinoscopy and video mediastinoscopy.

Cervical mediastinoscopy permits access to paratracheal and subcarinal lymph nodes, but it has limited access to the aortopulmonary (AP) window. One approach to the AP 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 left carotid artery.⁶ A more common approach to the AP window is through an anterior mediastinotomy—so-called anterior mediastinoscopy.⁷ Extended and anterior mediastinoscopy, as well as a video-assisted thoracoscopic approach, are techniques available to sample mediastinal lymph nodes in the AP 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.

SURGICAL PRINCIPLES

Frequent indications for mediastinoscopy include (1) staging patients with bronchogenic carcinoma⁸ and (2) obtaining tissue diagnoses in patients with unexplained adenopathy.⁹ Patients diagnosed with bronchogenic carcinoma are staged using a combination of modalities. CT of the chest determines the size and location of the primary tumor, the location and size of mediastinal nodes, and any associated lung parenchymal abnormalities (atelectasis, collapse, pneumonia, emphysema, or fibrosis). In addition, positron-emission tomography (PET) or PET-CT are essential in staging bronchogenic carcinoma. Mediastinal nodes larger than 1 cm in their short axis or PET-avid lymph nodes 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 is often required. 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 ...