159: Thoracoscopic Approach to Thymectomy with Advice on Patients with Myasthenia Gravis

Introduction

Thoracoscopy is the application of video imaging technology to standard thoracic surgical procedures. The thoracoscopic approach permits indirect visualization of the thoracic cavity without the necessity of performing a full thoracotomy. Before the current era, the standard surgical approach to thymectomy was through a midline sternotomy or a cervical collar incision. In the last two decades, however, thoracoscopic thymectomy has been used increasingly in selected patients as a means of reducing pain and recovery time while maintaining the quality of gland removal, as well as comparable remission and asymptomatic disease rates compared to other minimally invasive and open techniques.¹ Thoracoscopic thymectomy is a good alternative to standard surgical treatment with full sternotomy because it offers excellent visualization (superior to the collar incision) and avoids the morbidity of a sternal division. We enthusiastically advocate a thoracoscopic approach to myasthenia gravis (MG), thymic cysts, thymic masses, and other anterior mediastinal tumors, including small (<2 cm) thymomas.^2,3 Bulky thymomas may be better visualized through a standard sternotomy. In this chapter, we describe our technique for thoracoscopic thymectomy with particular advice on ensuring a complete resection.

For the purposes of this description, we will refer to the superior portions of the H-shaped thymus gland as the right or left cervical horns, and the inferior portions will be referred as the right or left lobes.

General Principles

Thoracoscopic thymectomy is well tolerated by patients of any age or gender owing to the minimally invasive nature of this approach. The usual position for a thoracoscopic procedure is the lateral decubitus position. We have lately added slight cervical flexion to permit caudal migration of the cervical horns and easier dissection, which obviates the need for a cervical incision. This position permits adequate instrumentation of the chest and rapid conversion to open thoracotomy in the event of bleeding or extended re-section. The patient must be intubated with a double-lumen endotracheal tube for split-lung anesthesia to permit selective deflation of the right or left lung. A left-sided double-lumen endotracheal tube is preferred because it is safer and easier to intubate the left mainstem bronchus owing to its length. Most thoracoscopic procedures can be performed with three ports: one for the camera and two for instrument access. It is important to place the ports as far apart from each other as possible to provide opposing angles of access to the intrathoracic target. A camera with a 30-degree angled telescope is also recommended for better intrathoracic visualization. Ports that have been placed too close together prevent adequate countertension on the tissues and cause crowding of instruments. A baseball diamond analogy has been used to describe port placement.⁴ The camera is at home plate, and the instruments are at first and third base. The target lies between the pitcher's mound and second base. A fourth port can be added later in the procedure to improve exposure and retraction ...