Video-Assisted Thymectomy



Video-Assisted Thymectomy


Mitchell J. Magee

Michael J. Mack



Neurologists and surgeons still debate the role of surgery in the management of myasthenia gravis, an autoimmune disorder of neuromuscular transmission affecting 2 out of every 100,000 people. Further adding to the controversy is the lack of randomized controlled trials comparing surgery, medical therapy, and the natural history of the disease and disagreement among surgeons as to what constitutes the best surgical therapy. Most surgeons agree that improved clinical outcomes correlate with completeness of thymectomy. But increased morbidity associated with increasingly invasive approaches, though aimed at improving outcomes by maximizing resection of thymic tissue, may ultimately deprive many patients of the benefits of surgical therapy owing to the unwillingness of patients and referring neurologists to consider surgery. Less invasive surgical approaches to thymectomy seek to minimize procedural morbidity, hasten recovery, and improve cosmesis while achieving equivalent outcomes by performing as complete a thymectomy as with conventional techniques. A number of minimally invasive approaches for thymectomy have been described, including both left and right thoracoscopic, bilateral alone, and thymectomy combined with a cervical incision. We have adopted and refined a right-sided video-assisted thoracic surgery (VATS) thymectomy as our preferred approach because of the superior exposure and facility with which the operative maneuvers can be performed. This chapter outlines the important technical details, rationale, and lessons learned in the development of our current technique of VATS thymectomy. It also touches briefly on the alternative VATS approaches and concludes with a report of our clinical outcomes.


Operative Technique of Vats Thymectomy


Preoperative Preparation and Patient Selection

The same general selection criteria used in determining those patients with myasthenia gravis who are most likely to benefit from thymectomy are suitable in selecting patients for the VATS approach. However, we now have no upper age limit for recommending thymectomy. Because we have been able to achieve a number of remissions in patients >50 years of age with advanced-stage disease and minimal residual thymic tissue, we do not consider advanced age a contraindication. Relative contraindications include a prior ipsilateral thoracotomy or pleurodesis procedure or severe concomitant pulmonary disease limiting tolerance of single-lung ventilation. The perioperative medical management and preparation of myasthenic patients for VATS thymectomy is less complex than for a more invasive procedure. We have not found it necessary to use plasmapheresis or other methods of preparation since exacerbation of the disease does not appear to occur with the less invasive approach.


Operative Setup

General anesthesia is utilized with a double-lumen endotracheal tube used for lung isolation. Neuromuscular blocking agents are avoided and short-acting narcotics are used preferentially for analgesia. We have not found it necessary to employ epidural anesthesia nor analgesia in the intraoperative or postoperative management of our patients. For our preferred right-sided approach, the patient is positioned in a 30-degree partial lateral, with a roll behind the right scapula, the left arm tucked along the patient’s side, and the right arm elevated on an arm board or in a sling above the patient’s head and draped out of the operative field. The right arm should be elevated enough to allow complete access to the right axilla.


Operative Technique

Four closed-port trocars to allow carbon dioxide insufflation are used to provide access to the mediastinum via the right hemithorax. The first of three 5-mm trocars is placed at the apex of an inverted triangle positioned halfway between the xyphoid and the sternal notch, in the posterior axillary line (Figure 184-1). A 5-mm 30-degree videothoracoscope is placed through this trocar and, after confirming collapse of the right lung, two additional 5-mm trocars are placed under direct vision. These trocars are both placed in the midaxillary line, one approximately two interspaces caudal and the other trocar two interspaces cephalad to the camera port (Figure 184-2). These trocars should provide working channels for instruments, positioned a comfortable distance apart, to be used by the operating surgeon to complete the dissection of the thymus and surrounding tissue. The assistant holds the camera, standing on the same side of the table and to the right of the surgeon, and elevates the thymic tissue utilizing a fan retractor placed through a 10- to 12-mm port. This last port is placed later in the procedure and positioned caudal and
anterior to the other ports in either the midaxillary or anterior axillary line; this incision is used for specimen retrieval after completion of the thymectomy. The 30-degree scope is essential in providing adequate visualization of the cervical region cephalad to the innominate vein and left posterolateral extents of the dissection approaching the left phrenic nerve. With minimal trauma produced by the 5-mm trocars, we have not hesitated to add or replace a trocar as needed to facilitate the dissection, but we now seldom find this necessary.






Figure 184-1. Anatomic landmarks for placing initial camera port for right VATS thymectomy.

High-flow carbon dioxide insufflation is routinely used with pressure limits set at 8 mm Hg. This greatly facilitates (a) collapse of the right lung, (b) access to and dissection of the mediastinal tissue planes, and (c) enhanced visualization of the cephalad extent of the cervical dissection. Routine instrumentation in addition to the videothoracoscope and trocars includes 5-mm endoscopic graspers or Debakey forceps, 5-mm hook electrocautery instrument, 5-mm ultrasonic harmonic scalpel, 5-mm endoscopic Kittner dissectors, 5-mm small or medium endoscopic Hemoclip appliers, and a 10-mm endoscopic fan retractor.

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Jun 25, 2016 | Posted by in RESPIRATORY | Comments Off on Video-Assisted Thymectomy

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