Transoral Video-Assisted Thyroidectomy and Its Clinical Implementation

Dear Editor:

We have read with interest the article by S.H. Woo entitled “Endoscope-assisted transoral thyroidectomy using a frenotomy incision,” ¹ which reported the case of a 35-year-old woman with a 0.5-×0.5-cm papillary thyroid microcarcinoma. This patient underwent a transoral right thyroidectomy by using a frenotomy incision of the mouth, accompanied by use of an endoscope system. The postoperative course was uneventful, and the patient was discharged on postoperative Day 7. Twelve months after the surgery, there were no long-term complications in thyroid and vocal cord function, articulation, or tongue movement. The patient was quite satisfied with the surgical outcome.

Despite the positive outcome of this case report, we would like to call attention to the risks of the transoral thyroid and parathyroid surgery as reported in two clinical pilot studies. In the first proof-of-concept study the approach consisted of a three-point access sublingually and bilaterally in the vestibule of the mouth.^2,3 This technique was performed on 8 patients suffering from nodular changes of the thyroid gland. The authors encountered various difficulties and concerns resulting in complications, such as paresthesia of the mental nerve in 6 cases (75%), conversion to open surgery due to specimen size in 3 cases (37.5%), palsy of the recurrent laryngeal nerve in 2 cases (25%) and one which was permanent (12.5%), and local streptococci infection at the vestibular incision site necessitating incision and irrigation in 1 case (12.5%). ³

Another group recently published results of their pilot study on transoral parathyroidectomy. ⁴ Between January 2010 and May 2012, 75 patients with primary hyperparathyroidism and a preoperative localized parathyroid adenoma were considered as eligible for transoral partial parathyroidectomy (TOPP). Only 5 (7%) female patients consented to undergo TOPP. The access was accomplished via a 20-mm incision in the lateral floor of mouth (in the first patient) or in the frenulum of the tongue. In 3 patients, a parathyroid adenoma could be removed via the transoral access; in 2 patients (40%), the procedure had to be converted to the conventional technique. Median time until resection of a parathyroid adenoma was 122 minutes (range, 45–175 minutes). One patient (20%) had transient recurrent laryngeal nerve palsy, whereas 1 patient (20%) suffered from a transient palsy of the right hypoglossal nerve and a slight but persisting dysgeusia. Three patients (60%) developed a hematoma of the mouth floor and swallowing problems. Furthermore, in 4 patients (80%), the visual analog scale pain score was high (>7) within the first 2 postoperative days. The authors concluded that although TOPP is feasible, it is poorly accepted by patients, and its complication rate is high. ⁴

Despite these drawbacks, we are still convinced that transoral thyroid and parathyroid surgery is a promising approach because it is the only method that is at the same time minimally invasive and cosmetically optimal. Naturally predetermined cervical layers are being separated instead of being cut and divided. Furthermore, the mouth mucosa can be sutured directly and repairs itself without leaving any visible scars. However, at this stage, we feel that further preclinical studies consisting of refinements of the access itself and development of suitable and adapted instruments are mandatory before commencing further human trials. We encourage innovative working groups like that of Woo to further continue investigating this new promising approach. By doing this, we should always bear in mind that we are dealing with highly standardized and low-morbidity thyroid and parathyroid surgery.