Transcervical thymectomy was the approach used for the earliest described thymectomies,20 but was replaced by the transsternal approach by Blalock and his contemporaries midway through the past century.4 We prefer the video-assisted transcervical thymectomy (VTCT) approach for the treatment of nonthymomatous MG since, despite being a less invasive procedure, it gives excellent bilateral exposure of the thymus, including the lower poles, and permits complete thymectomy. Furthermore, unlike transthoracic video-assisted thymectomies, the transcervical route obviates entry into the pleural spaces, obviates the need for chest tubes, provides enhanced exposure in the neck region, and does not require split lung anesthesia via a double-lumen endotracheal tube.
Relative contraindications to a transcervical approach include prior cervicomediastinal surgery and/or radiation, and cervical spine pathology limiting extension of the neck. Surgery is performed in the supine position with an inflatable bag under the shoulders. The bag is inflated to provide good neck extension. Both arms are tucked in at the sides. The neck and full anterior chest is prepped in case a sternotomy is required. A curvilinear incision is made in the skin at the base of the neck, one finger breadth above the sternal notch, and extended on each side to the medial border of sternocleidomastoid muscle (Fig. 158-1). This incision is extended through the skin and platysma muscle. Flaps are then developed superiorly to the level of the inferior aspect of the thyroid cartilage and inferiorly to the sternal notch. The strap muscles are then split vertically in the midline and elevated bilaterally to expose the superior poles of the thymus gland, which lie opposed to the posterior surface of the sternothyroid muscles. It is imperative that this be done using careful sharp dissection with meticulous attention to control of small blood vessels with electrocautery. A bloodless field makes it significantly easier to delineate thymic tissue from fatty tissue in the neck. Each superior pole of the gland is mobilized near the inferior thyroid vein. The upper pole is divided between ties at the point where the thymic tissue terminates. A heavy silk suture, cut long, is placed on each upper pole and used as a “traction” suture to facilitate orientation and traction of the gland (Fig. 158-2). The superior poles are dissected and pulled up, and the capsule of thymus gland is followed inferiorly to the thoracic inlet.
An incision is made in the skin at the base of the neck, one finger breadth above the sternal notch, and extended on each side to the medial border of sternocleidomastoid muscle.
Cooper retractor is in place. Sutures are placed on each upper pole and used as a “traction” sutures.
The retrosternal (retromanubrial) space is cleared to accommodate the placement of the Cooper retractor.9 The Cooper retractor blade is placed beneath the manubrium to elevate it and open the thoracic inlet (Fig. 158-2). The inflatable pillow that was placed at the start of the procedure is deflated at this point to further improve the thoracic inlet exposure. Care is taken to make sure that the patient's head is not elevated off the operating table by the sternal retractor.
We use a 5-mm 30-degree videothoracoscope at the right lateral aspect of the neck incision to provide light for direct operating and a video magnified view of the operating field on a monitor (Fig. 158-3). The dissection of the gland is carried down into the thorax using primarily blunt dissection. The arterial vessels entering the gland laterally from the internal thoracic artery branches are clipped with stainless steel clips. The thymic veins (there are often several), which drain into the innominate vein, are identified posteriorly and divided between stainless steel clips. The assistance of the videothoracoscope provides good visualization of the lower mediastinum, down to diaphragm if necessary. The ventilation rate and tidal volume can both be decreased to facilitate exposure in the mediastinum. The dissection of the gland is carried down alternately on both sides until the inferior poles of the gland are clearly identified and a dissecting “peanut” on a long-curved Swedish-Debakey dissector is used to sweep up each inferior pole. The dissector is placed on the pericardium, distal to the inferior pole of the thymus gland, and in a sweeping motion the gland is extracted from the inferior mediastinum. A 7 Jackson-Pratt (JP) drain (Zimmer, Dover, OH) is inserted through a lateral stab wound in the neck, placed down into the mediastinum, and the Cooper retractor is removed. The strap muscles are approximated and the platysma and the skin are closed. Patients are discharged home on the morning after surgery.
Operative view illustrating the position of the telescope and instruments through the cervical incision.
In rare instances, if complete thymectomy cannot be performed by removing the thymus and its capsule, the operation is usually converted to a partial upper sternotomy. This is carried out by the addition of a vertical skin incision extending down from the sternal notch to the lower end of manubrium. The sternal bone incision is then extended laterally in the third intercostal space (in a “T”) with the oscillating saw to create a partial upper sternotomy, which provides sufficient exposure to easily complete the operation.