167: Robotics: Thymectomy

Introduction

The standard treatment of isolated disorders of or related to the thymus is typically thymectomy. Indications include known or suspected thymoma, thymic carcinoid tumor, myasthenia gravis (MG) with or without concomitant thymoma, and benign thymic lesions, such as cysts or discrete hyperplasia. Regardless of the indication, complete thymectomy is the ultimate goal in order to avoid retention of ectopic thymic tissue. This is felt to be particularly important in the surgical management of MG.¹ The most common surgical approach to thymectomy is the classic transsternal approach (Chapter 160), which has proved effective and safe, both in the setting of thymic neoplasms and MG.²

In the case of MG, however, many patients and neurologists are hesitant to undergo transsternal thymectomy despite evidence demonstrating clinical improvement because of concerns about perioperative morbidity, pain, and cosmesis. As a result, alternative surgical approaches were developed, including the transcervical method, the video-assisted thoracic surgery (VATS) thymectomy, and most recently robotic thymectomy. VATS thymectomy attempted to replicate complete thymectomy performed under direct, intrathoracic vision but eliminating the morbidity associated with dividing and spreading the sternum.³ Meyer et al.⁴ showed in a single-institution cohort study of VATS versus transsternal thymectomy for MG that there were equivalent clinical outcomes and improved perioperative results (need for postoperative ventilation and length of stay). Despite this, minimally invasive VATS thymectomy never became a widely accepted technique, and significant controversy still exists regarding the optimal surgical approach to thymectomy.

The reason for this controversy is unclear, but similar to VATS lobectomy, it is likely due to a combination of factors, including the technical limitations of an unstable two-dimensional camera platform and limited maneuverability of instrumentation. These issues are especially enhanced in the limited confines of the anterior mediastinum. It was precisely for this application that the master–slave robotic surgical system was developed (da Vinci Surgical System; Intuitive Surgical, Sunnyvale, CA). The three-dimensional (3D) visual system and wristed instrumentation was specifically designed for closed chest cardiothoracic surgery in the anterior and middle mediastinum. However, while this original indication has never been widely realized, other indications evolved, including thymectomy. The earliest case reports consist of only patients with nonthymomatous MG,^5,6 but subsequent series have included those with encapsulated thymic lesions as well.^7–10

This chapter reviews the general principles and clinical aspects of robotic thymectomy with an emphasis on patient selection, preoperative preparation, technical aspects, and perioperative outcomes.

General Principles

The guiding principle that must be remembered when one is considering utilizing robotic surgical systems for thymectomy is that the ultimate goal is to perform complete resection without violating the capsule of the thymus or any associated lesion. It is up to the surgeon to decide whether this can be safely and appropriately achieved though a minimally invasive robotic approach. The incision strategy, conduct of the procedure, and postoperative ...