What are the operative steps of a bilateral thyroidectomy, highlighting relevant anatomy?

From the Guidelines

A bilateral thyroidectomy involves the complete removal of both thyroid lobes while preserving critical surrounding structures, and the procedure should be performed with meticulous attention to the recurrent laryngeal nerve (RLN) and parathyroid glands to minimize the risk of morbidity and mortality. The procedure begins with patient positioning in a supine position with neck extension, followed by a transverse collar incision about 2 cm above the sternal notch 1. After creating subplatysmal flaps, the strap muscles are divided in the midline and retracted laterally. The middle thyroid vein is identified and ligated first. The superior thyroid vessels are then carefully dissected and ligated close to the gland to avoid injury to the external branch of the superior laryngeal nerve, which supplies the cricothyroid muscle. The inferior thyroid artery is identified and ligated, taking care to preserve the RLN which typically courses near this vessel 1.

The RLN must be identified on both sides as it ascends in the tracheoesophageal groove before entering the larynx; injury can cause vocal cord paralysis. The parathyroid glands (typically four) must be identified and preserved with their blood supply to prevent postoperative hypocalcemia. After the thyroid is mobilized, the gland is removed from its attachment to the trachea, and hemostasis is secured. The strap muscles are reapproximated, and the skin is closed.

Some key points to consider during the procedure include:

• The use of routine recurrent nerve visualization and dissection to reduce nerve palsy during thyroid and parathyroid surgery 1
• The importance of preserving the parathyroid glands and their blood supply to prevent postoperative hypocalcemia
• The need for careful dissection and ligation of the inferior thyroid artery to avoid injury to the RLN
• The use of intraoperative neural monitoring (IONM) in selected high-risk patients to reduce the risk of bilateral palsy 1

Postoperatively, patients require monitoring for respiratory distress (from hematoma), hypocalcemia (from parathyroid injury), and voice changes (from RLN injury) 1. Thyroid hormone replacement therapy with levothyroxine (typically starting at 1.6 mcg/kg/day) will be necessary following complete thyroidectomy.

It is also important to note that unintentional RLN injury is a predictable but not preventable event, and bilateral palsy still represents a dramatic clinical condition around the globe, for both surgeons and patients 1. Therefore, a gently and meticulous surgical technique with visual identification of the nerve should be always adopted, and a precise and sufficiently comprehensive filling of the surgical report, testifying RLN identification and its integrity at the end of the procedure, is of paramount importance 1.

From the Research

Operative Steps of Bilateral Thyroidectomy

The operative steps of a bilateral thyroidectomy involve several key stages, including:

• Incision and exposure of the thyroid gland
• Identification and preservation of the recurrent laryngeal nerves and external branches of the superior laryngeal nerves
• Dissection of the superior pole of the thyroid gland, utilizing the avascular plane between the superior pole and the cricothyroid muscle
• Medial retraction of the gland and dissection of the lateral aspect of the thyroid lobe
• Protection of the recurrent laryngeal nerves and preservation of the blood supply to the parathyroid glands through "capsular dissection"
• Ligation of the tertiary branches of the inferior thyroid artery on the gland surface

Relevant Anatomy

The relevant anatomy for a bilateral thyroidectomy includes:

• The recurrent laryngeal nerves, which are closely associated with the superior parathyroid glands 2
• The external branches of the superior laryngeal nerves, which are located in the avascular plane between the superior pole of the thyroid gland and the cricothyroid muscle 3
• The parathyroid glands, which are typically located on the posterior surface of the thyroid gland and require preservation of their blood supply 3, 2
• The inferior thyroid artery, which provides blood supply to the thyroid gland and parathyroid glands 3

Surgical Techniques

Surgical techniques for bilateral thyroidectomy emphasize the importance of:

• Meticulous dissection and identification of critical anatomy 3, 4
• Preservation of the recurrent laryngeal nerves and parathyroid glands 3, 2
• Use of capsular dissection to protect the recurrent laryngeal nerves and preserve the blood supply to the parathyroid glands 3
• Ligation of the tertiary branches of the inferior thyroid artery on the gland surface 3
• Consideration of the relationship between the recurrent laryngeal nerve and the superior parathyroid gland, which can vary depending on the height of the thyroid lobe and the presence of cancer 2