Trans-Oral Endoscopic Thyroidectomy Vestibular Approach (TOETVA)

Abstract

Numerous minimally-invasive approaches to thyroidectomy have been developed over the years to minimize the neck surgical scar, many of which are performed using endoscopic or robotic assistance. However, a more diminutive anterior cervical scar still remains a problem for some patients, as well as more extensive dissections for remote access operations. Therefore, natural orifice surgery was adopted at select institutions, in an effort to perform a truly scarless thyroidectomy. Transoral endoscopic thyroidectomy has been the latest approach developed, known as the natural orifice transluminal endoscopic thyroidectomy which is categorized as a natural orifice transluminal endoscopic surgery (NOTES) procedure. There are several ways to perform the natural orifice transluminal endoscopic thyroidectomy. We present the transoral endoscopic thyroidectomy vestibular approach under general anesthesia.

Case Overview

Background

Witzel et al. first reported the successful experimental performance of the endoscopic sublingual transoral thyroidectomy, through a single port using a modified axilloscope in ten porcine models and two human cadavers in 2008.¹ In 2009, Benhidjeb et al. introduced a 3-port access vestibular approach; however, significant postoperative complications were noted, including temporary and permanent recurrent laryngeal nerve (RLN) injury, as well as transient mental nerve injury.² More recently, successful transoral endoscopic thyroidectomy has been performed in many patients, without conversion to the standard open approach.³

Focused History of Patient

The patient is a 45-year-old female who presents with a 2-cm left thyroid nodule. She had some throat complaints in 2014 at which time ultrasound (US) showed small subcentimeter thyroid nodules, and she was reassured. Subsequently, a few months ago she had an MRI of her neck for evaluation for her cervical pain and was noted to have an increase in the size of the left thyroid nodule. Now, a more recent US shows an increase in the thyroid nodule. There are no complaints of hoarseness or difficulty breathing. Occasionally, she has a globus sensation while supine. She has no history of radiation to the neck or face and no previous cervical operations. She is biochemically euthyroid and otherwise healthy, with a weight of 82 kg and a BMI of 29.2 kg/m.² The physical exam revealed a palpable lesion in the left thyroid gland consistent with the sonographic findings, and flexible laryngoscopy demonstrated normal vocal cord movement.

Imaging Studies

Ultrasound shows a 6.0 x 1.9 x 1.6-cm right thyroid lobe and a 5.9 x 1.3 x 1.6-cm left thyroid lobe. In the left side there is a 2.0 x 1.0 x 1.2-cm thyroid nodule (previously 1.3 x 0.8 x 0.8 cm). In the right thyroid lobe there are several colloid cysts, 0.4 cm in maximal dimension. Fine-needle aspiration (FNA) reveals a Hurthle cell neoplasm.

Options for Treatment

Various options including continued surveillance were discussed with the patient, but since the lesion had demonstrated interval growth, and FNA revealed a Hurthle cell neoplasm, she wished to have a left thyroid lobectomy with transoral endoscopic thyroidectomy vestibular approach (TOETVA).

There are innumerable surgical options for the removal of the thyroid or parathyroid glands. The standard of care remains the open surgical approach; however, various minimally invasive techniques have been developed, largely for cosmetic purposes (i.e. the avoidance of a neck scar). In addition to cosmetic benefits, minimally invasive thyroidectomy has been shown to be feasible and effective with similar complication rates to the standard approach.

Discussion

Anuwong initially reported on 60 patients undergoing TOETVA for various thyroid diseases, including thyroid cyst, nodular goiter, follicular neoplasm, Graves’ disease, and papillary microcarcinoma.³ No conversions were reported, and 3 patients (5%) reported transient hypoparathyroidism. Two (3.3%) reported RLN palsy and no permanent hypoparathyroidism, permanent RLN, or mental nerve injury. The postoperative infection rate was 0% with only one (1.67%) found to have a delayed hematoma. In 2016, Drs. Udelsman and Carling performed and reported the initial experience in the United States; two cases of transoral parathyroidectomy and five cases of TOETVA. The operations were successful, from both a technical and cosmetic perspective.⁴ The TOETVA can be performed with or without intraoperative neuromonitoring as reported by Wang et al. and Dionigi et al.^5, 6 No transient or permanent RLN palsy were reported.

Recently, indications for TOETVA have been amended to now include the following criteria⁷:

1. Thyroid diameter < 10 cm
2. Benign tumor
3. Follicular neoplasm
4. Papillary microcarcinoma
5. Graves’ disease
6. Substernal goiter (grade 1)

Exclusion criteria include patients unfit for surgery or unable to tolerate anesthesia, and its role in thyroid cancer is still controversial.⁷ Moreover, transoral endoscopic parathyroidectomy (TOEPVA) for primary hyperparathyroidism and renal hyperparathyroidism has also been reported by Sasanakietkul and Carling et al.^8, 9 Despite overall positive outcomes, there are several disadvantages of transoral thyroidectomy. The open approach provides a better anatomical understanding and surgical view than the view obtained with TOETVA (craniocaudal). Additionally, potential injury to mental nerves with this approach requires extensive surgeon experience to avoid this injury.¹⁰ Furthermore, because the incisions are made through the oral mucosa, there may be greater chance of infection; therefore, antibiotics are recommended preoperatively, whereas this is usually avoided with the open cervical approach. Lastly, some patients may experience temporary postoperative chin swelling with numbness, as well as a limitation of cervical extension, which usually resolve in 3–6 months. Overall, TOETVA has been shown to be a promising procedure with feasibility and safety in select patients.

Surgical Technique and Results

In TOETVA, the following instruments are used: 30°, 10-mm endoscope, dilator, L-hook with monopolar coagulator, Maryland dissector, and laparoscopic vessel-sealing device. Preoperative prophylactic antibiotics and preparation with chlorhexidine are recommended. The patient’s airway is secured by a nasotracheal tube. The patient is positioned supine on the operating table, with the neck extended. A 10-mm incision (for placement of camera trocar) is made at the mid-vestibule. Two 5-mm incisions (working ports) are made superolaterally, away from mental nerves bilaterally. Hydrodissection is performed using a Veress needle by injecting a solution of diluted epinephrine (1 mg of epinephrine: 500 ml of normal saline). A tract is created with the dilator, and then the port is advanced, and an endoscope passed through the 10-mm incision. CO₂ insufflation is limited to a maximum pressure of 6 mmHg to minimize the occurrence of subcutaneous emphysema. Dissection is carried down in a subplatysmal fashion to create the working space. The strap muscles are identified and divided at midline using an L-hook or vessel-sealing device. A hanging suture is created by passing a suture transcervically through the strap muscles and then back through the skin to elevate the strap muscles. After the thyroid gland is exposed, dissection is carefully undertaken over the isthmus, and then the thyroid is divided at the midline with the vessel-sealing device. The superior thyroid artery and vein are identified and transected close to the thyroid gland to avoid superior laryngeal nerve injury, as well as devascularization of the superior parathyroid glands. Next, the middle thyroid vein is identified and transected to retract the thyroid medially. At this point, the RLN can be identified in the tracheoesophageal groove. In a similar fashion, the inferior thyroid artery and vein are identified and transected, with preservation of the inferior parathyroid glands. The specimen is retrieved through the 10-mm incision using an endobag. After hemostasis is achieved, the strap muscles are reapproximated and the incisions are closed using absorbable sutures. A chin support is recommended for 24 hours to avoid contamination of the incisions with the patient’s saliva, as well as to minimize postoperative swelling. Oral intake can be restarted postoperatively.

Pathology and Follow-up

The pathology revealed a 2-cm benign Hurthle cell adenoma in the left thyroid lobe, completely excised. The patient did very well postoperatively and was discharged on postoperative day one. She was then seen 10 days after, and the oral incisions were difficult to even identify. She had normal voice function and examination with flexible laryngoscopy.

Special Equipment

1. 30°, 10-mm endoscope
2. Dilator
3. L-hook with monopolar coagulator
4. Maryland dissector
5. Laparoscopic vessel-sealing device

Disclosures

Nothing to disclose.

Statement of Consent

The patient referred to in this video article has given their informed consent to be filmed and is aware that information and images will be published online.