By Ashleigh Elkins

Thyroidectomy is a commonly performed surgical procedure which involves the removal of the thyroid gland. Historically, thyroidectomy has been performed as an open procedure with an incision in the anterior neck, which is usually longer than 6 centimetres.

The open procedure provides the surgeon with good visualisation and exposure of the thyroid gland and surrounding structures, such as the recurrent laryngeal nerve and the parathyroid glands.[1] Open thyroidectomy carries a low complication rate and is regarded as a safe procedure.[2] A disadvantage of open thyroidectomy is scar formation post-operatively. The incision is made in the lower, anterior neck. This area is not typically covered by clothing and is visible to others, and patients may be dissatisfied with the scarring.[1] The incision is typically made into one of the creases into the lower neck, and with good post-operative wound care and taping, the wound usually settles sufficiently to blend in with the creases of the skin. Open thyroidectomy also requires more dissection of neck tissues, which can contribute to post-operative pain.

Minimally Invasive Techniques

In order to improve cosmetic outcomes post-surgery, post-operative pain and duration of hospital stay, minimally invasive thyroidectomy techniques have been developed. These procedures typically utilise endoscopy or video assistance and involve smaller incisions than the open procedure.[2,3] Some endoscopic techniques involve making no incisions into the neck. Instead, the thyroid is approached via incisions made into the axilla, chest or breast. This ensures that the post-operative scars are less visible than those made in the neck. However, a disadvantage of these approaches is that they involve a substantial degree of tissue resection in sites distant from the thyroid gland. Although they may achieve superior cosmetic outcomes, they may not be minimally invasive from a tissue resection point of view.[1]

As there are no cavities in the neck, the amount of space available for the surgeon to work within is limited. Hence, endoscopic thyroid surgery requires the creation of a working space within the neck, which can be achieved by carbon dioxide insufflation, where carbon dioxide is blown into the neck to create a working space. This is a technique commonly used in endoscopic abdominal surgery. Potential complications include elevated blood levels of carbon dioxide and subcutaneous emphysema.[3]  Another technique which has been devised to increase the working space within the neck is known as anterior skin lifting, in which the skin is pulled upwards and away from the body.[3]

Incision Lengths

In minimally invasive video assisted thyroidectomy, an incision is made into the neck that is approximately 2 centimetres in length. This incision is made either to one side of the thyroid gland, or slightly above the sternal notch. In comparison, traditional open thyroidectomy is performed through an incision into the base of the neck, which is generally around 6cm to 10cm in length, depending on the size of the neck and the thyroid gland.[1]

However, depending on the underlying pathology and size of the thyroid gland to be removed, open thyroidectomy may be possible through a smaller incision.[4] The length of incisions made into the chest, axilla and breast vary. These are usually small incisions and due to their position, are usually covered by clothing.[3] For patients undergoing a hemithyroidectomy procedure, which removes one lobe of the thyroid gland, the neck incision is usually smaller, at around 4cm to 5cm.

Who is Eligible for Minimally Invasive Thyroid Surgery?

One of the issues with minimally invasive thyroid surgery is that not all patients are eligible for the procedure. Generally speaking, patients are considered to be eligible for minimally invasive thyroid surgery if they have small thyroid nodules (that is, the largest diameter of the nodule is less than 30mm), the volume of the thyroid gland is less than 20mL (this is usually determined by ultrasound), if they have not had any previous neck surgery or radiation treatments to the neck, and if the patient does not have thyroiditis.[5] Patients with malignancies are generally treated with an open thyroidectomy procedure. Patients who are best suited to undergoing minimally invasive thyroid surgery have small nodules which are located within normal sized or slightly enlarged thyroid glands.

Reported Outcomes of Minimally Invasive Thyroid Surgery

Open thyroidectomy is a safe procedure with a low complication rate and results in good patient outcomes. The main issue with the open procedure is that sometimes patients are not satisfied with the appearance of the scar. Minimally invasive thyroid surgery was developed to reduce the size of the neck scar. The results of minimally invasive thyroid surgery have been promising in patients who have been carefully selected and are appropriate candidates for the minimally invasive surgery. Patients who have been selected for the minimally invasive surgery, but are not suitable for the procedure (usually because their thyroid gland is too large), will have their operation converted to an open procedure to ensure the best results are obtained.

Patients undergoing the minimally invasive procedure are generally observed overnight in hospital in case of complications. This is also standard for many patients who undergo the open procedure. Complication rates, including post-operative bleeding, recurrent laryngeal nerve palsy, and hypocalcaemia following minimally invasive thyroid are comparable to the open procedure. Minimally invasive techniques may be associated with a better cosmetic outcome and less pain post-surgery.

Advantages of Minimally Invasive Thyroid Surgery

Minimally invasive thyroid surgery is generally performed in young, fit women who have few skin creases in the neck, who meet the above selection criteria. This is because the minimally invasive technique produces a smaller, less visible scar than the open procedure.

Disadvantages of Minimally Invasive Thyroid Surgery

One of the main limitations of minimally invasive thyroid surgery is that it is only suitable for a small number of patients with specific indications that meet the selection criteria. The procedure is also more technically demanding and has a longer operative time than traditional open thyroidectomy. Another disadvantage is that there is a learning curve associated with the procedure. It is also difficult for surgeons to gain experience with the technique. This is because the procedure is only suitable for a small number of patients, and the open technique is therefore more routinely performed.

If you have questions about thyroid nodules or thyroid surgery contact your local doctor, who will arrange for you to visit a thyroid surgeon.

References

[1] Timon C, Rafferty M. Minimally invasive video-assisted thyroidectomy (MIVAT): technique, advantages and disadvantages. Operative Techniques in Otolaryngology (2008) 19, 8-14.

[2] Rafferty M, Timon C. Minimal incision thyroidectomy. Operative Techniques in Otolaryngology (2008) 19, 2-7.

[3] Shimizu K. Minimally invasive thyroid surgery. Best Practice & Research Clinical Endocrinology and Metabolism (2001); 15(2):123-137.

[4] Rafferty M, Miller I, Timon C. Minimal incision for open thyroidectomy. Otolaryngology Head and Neck Surgery (2006); 135(2): 295-298.

[5] Miccoli P, Berti P, Raffaelli M, Conte M, Materazzi G, Galleri D. Minimally invasive video-assisted thyroidectomy. The American Journal of Surgery (2001); 181:567-570.

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