Technique of total thyroidectomy for large substernal goiters

The patient is induced with a general anesthetic and orotracheally intubated, which may require fiber optic techniques. We do not use intraoperative laryngeal nerve monitoring; thus, long-acting muscle relaxants may be used to facilitate retraction and exposure. The patient is positioned with both arms tucked by his/her sides in a “beach chair” position with a folded blanket behind the scapula to allow for maximal passive cervical extension. The endotracheal tube is secured away from the operative field.

A 6- to 10-cm transverse Kocher incision is centered 2 fingerbreadths above the sternal notch. The platysma is divided sharply and a superior subplatysmal flap is raised to the thyroid cartilage. A smaller inferior flap is dissected to the sternal notch. The “midline” of the strap muscles is then identified which is often deviated by an asymmetric goiter as illustrated (Figure 1B). These strap muscles are separated in the midline from the sternal notch to the thyroid cartilage protecting the anterior jugular veins. The anterior surface of both thyroid lobes is then exposed by blunt dissection. Often as the sternohyoid muscles are retracted the sternothyroid muscles may be divided without consequence as they are often very thin and attenuated (Figure 1C).

The thyroid isthmus is exposed by ligating the arborizing venous network on the superior and inferior aspect of the isthmus. The avascular plane is developed posterior to the isthmus at the midline of the deviated trachea with a curved clamp. The isthmus is then divided with electrocautery with the clamp beneath the gland protecting trachea. If this is unusually vascular, the isthmus is clamped, transected and ligated.

In contrast to our usual technique of securing the superior thyroid artery later in the dissection, it may be advantageous to address this vessel early in a large goiter. The artery is often elongated and more readily delineated with modest dissection of the strap muscles superiorly. The superior pole of the thyroid is then exposed to isolate (gently dissecting the external branch of the superior laryngeal nerve away from the vessels), clamp, divide and ligate the superior thyroid vessels (Figure 2). To further emphasize, care must be taken to create a window medial to the superior thyroid vasculature immediately adjacent to the thyroid to avoid injury to the superior laryngeal nerve. Gentle lateral retraction of the upper portion of the gland with a Kocher or Lahey clamp will further improve visualization. In extremely large goiters the strap musculature may have to be divided completely but this is uncommon in our experience. With the superior vasculature divided the gland becomes more mobile improving exposure, diminishing the considerable vascularity of the gland, and facilitating subsequent delivery out of its bed.

Once the superior pole has been mobilized (if the anatomy has been favorable to proceed with this step initially), the remaining mass of the gland is delivered into the wound by carefully dissecting the strap muscles off of the goiter, developing the avascular areolar plane anterior to the common carotid artery throughout the entire length of the exposure. The only significant anatomic structure to cross the carotid artery over this segment is the middle thyroid vein which is isolated and divided. The surgeon's finger is insinuated under the strap muscles and immediately against the thyroid, “hooking” around the inferior aspect of the substernal component, separating its loose attachments in the mediastinum, and delivering it into the neck (Figure 3). This may have to be performed in advancing, successive steps with additional superior retraction by placement of Lahey clamps to facilitate careful advancement of a finger around the entirety of the gland. Rarely, a spoon may also be utilized to facilitate this delivery.

With the goiter delivered into the field, out of its bed, and retracted by the assistant, the common carotid artery and lateral aspect of the trachea are exposed. The surgeon must be aware that the recurrent laryngeal nerve (RLN) may be located more anteriorly than expected as the goiter and trachea are rotated (Figure 4). There also may be a portion of thyroid that has insinuated itself between the RLN and the trachea. For these reasons we believe that it is safest to identify the RLN rather low in the neck, allowing for it to be traced cephalad to the thyroid.

Once the RLN is in clear view, all of the remaining vascular and soft-tissue attachments anterior to the nerve and around to the divided thyroid isthmus in the midline may be divided. Although it may be difficult to locate, the inferior parathyroid gland is sought and often cannot be retained in situ. It is biopsied for identity confirmation, then immediately minced and autotransplanted into the sternocleidomastoid muscle. The RLN is then able to be followed cephalad to its laryngeal insertion by dividing the vascular attachments coursing anterior to the nerve. As the dissection over the nerve nears the thyroid capsule the superior parathyroid gland is identified and the tiny branches from the typically large inferior thyroid artery are preserved (Figure 4). Just before insertion into the larynx, the RLN will arc slightly posteriorly. The nerve may be gently pushed more posteriorly at this point to aid in visualizing the remaining thyro-tracheal attachments. Attention is returned to the midline where the tracheal attachments may be divided with a combination of cautery, bipolar cautery, and hemostatic clips as the dissection proceeds laterally toward the identified insertion of the RLN into the larynx. Once this pedicle is dissected down to the last few millimeters, a 2-0 silk ligature is secured around the pedicle which is divided with a scalpel releasing the last attachment of the enlarged thyroid lobe. The contralateral side is removed in an identical fashion and is often more easily exposed because there is now more room for mobilization and exposure.

A single 7-French soft silastic drain is placed coursing through both thyroid beds exiting just lateral to the edge of the skin incision. If the strap muscles were divided, they are reapproximated with figure-of-eight 3-0 Vicryl sutures. The strap muscles are reapproximated in the midline with interrupted 3-0 Vicryl suture. Care is taken to leave an inferior opening to allow for subcutaneous decompression of any central neck hematoma in the event of postoperative hemorrhage. The platysma is reapproximated with interrupted 3-0 Vicryl suture and the skin is closed with a running 4-0 subcuticular Vicryl suture without knots. Steri-strips are applied with a loose bandage.