Transoral endoscopic thyroidectomy vestibular approach versus conventional open thyroidectomy for the treatment of benign thyroid tumours: A prospective cohort study

Abstract

Introduction:

Thyroid tumours are a common condition and open surgery is a conventional method for treating benign thyroid tumours when surgery is indicated. In this study, we evaluate the outcomes of benign thyroid tumour treatment using transoral endoscopic thyroidectomy via vestibular approach (TOETVA) and compare the results with those of conventional open thyroidectomy (COT).

Patients and Methods:

We conducted a prospective cohort study between 100 patients who underwent TOETVA and 100 who underwent COT surgery for benign diseases from June 2018 to December 2021 in our hospital. Outcomes between the two groups, including post-operative complications, operative time and length of stay, were compared.

Results:

The surgical time in the TOETVA group was significantly longer than in the COT group. The operative time of lobectomy in the TOETVA and COT groups was 77.5 ± 13.3 and 51.5 ± 4.2 min, respectively, with a P < 0.001. The operative time of total thyroidectomy in the TOETVA and COT groups was 108.1 ± 7.0 and 65.0 ± 4.1 min, respectively, with a P < 0.001. There was no difference in post-operative length of stay between the two groups. In TOETVA group, there were no patients who converted to open surgery. Amongst all 200 patients in the study, there were no cases of post-operative bleeding. The transient hypoparathyroidism rate after surgery in the TOETVA and COT groups was 3% and 2%, respectively, with no statistically significant difference (P = 0.651). Similarly, the transient recurrent laryngeal nerve injury rate showed no difference between the two groups, with rates of 5% and 4% in the TOETVA and COT groups, respectively (P = 0.733). There were no cases of post-operative infection in either group in our study. At 3 months postoperatively, the cosmetic satisfaction were significantly higher in the endoscopic groups than in the conventional group (P < 0.001).

Conclusions:

TOETVA is a safe and effective method, with a low complication rate and optimal aesthetic results compared to traditional surgery to treat benign thyroid tumours.

INTRODUCTION

Thyroid tumours are a common condition with a prevalence rate of up to 50%–67% of the population. However, most of these nodules are benign, and the malignant rate only accounts for 4%–5%.[1,2,3] Common benign thyroid tumours include colloid nodules, thyroid cysts and adenomas. Most benign nodules only require monitoring and do not require intervention. Benign conditions that occasionally require surgical resection include lesions such as multinodular goitres, Graves’ disease and some forms of thyroiditis. With surgical intervention being a viable option for treating benign thyroid conditions, there is a demand for better cosmetic results than what is currently achieved with the standard cervical incision. Most individuals with these conditions are young women, and even with optimal healing, they are left with a permanent scar on their neck. This can cause considerable psychological distress, particularly for those prone to developing hypertrophic or keloid scarring in this noticeable location.[2] Currently, there are many approaches to thyroidectomy to minimise the cosmetic impact of a conventional thyroidectomy, such as the axillo-breast, transaxillary, retroauricular and transoral approaches.[4,5] The transoral endoscopic thyroidectomy vestibular approach (TOETVA) is increasingly used worldwide due to having ideal cosmetic results. We have successfully implemented this technique in our hospital since 2018 and it is now routinely performed.[6] In this study, we evaluate the outcomes of benign thyroid nodule treatment using TOETVA and compare the results with those of traditional open surgery.

PATIENTS AND METHODS

Patients

We conducted a prospective cohort study between 100 patients who underwent TOETVA and 100 who underwent conventional open thyroidectomy (COT) surgery for benign diseases from June 2018 to December 2021 in our hospital. The surgeon selected patients who showed an interest in scarless surgery and had favourable characteristics as potential candidates for TOETVA, including (1) the patient’s motivation to avoid a cervical scar; (2) symptomatic benign nodules <6 cm; (3) cytologically indeterminate nodules; (4) estimate thyroid diameter <10 cm on ultrasound; (5) estimated gland volume <45 mL on ultrasound; (6) symptomatic Hashimoto’s thyroiditis and (7) Grave’s disease. Non-favourable features for TOETVA eligibility included (1) substernal goitres; (2) previous neck and chin surgery and (3) previous neck radiation. Thyroid lobectomy was performed in patients with a single benign nodule or multinodules but localised in one lobe, and total thyroidectomy was for patients with multinodules in two lobes.

All patients were informed about the risks, benefits and alternatives of the TOETVA and COT procedures. The study protocol was reviewed and approved by The Institutional Review Board of Vietnam National Cancer Hospital. Written informed consent was obtained, and all data were collected anonymously.

Surgical procedure for TOETVA surgery

The procedure of the TOETVA approach was described in detail in our previous articles.[6] The patient was placed in the supine position with the neck extended. General anaesthesia with nasotracheal intubation was initially implemented on the patient. First, we injected about 10 mL dilute epinephrine-saline solution (1:200,000) into the lower lip down to the tip of the chin. The inverted U-shaped 1-cm midline incision approximately 2 cm above the frenulum labii inferioris. Then, we inserted the first 10 mm trocar. The carbon dioxide insufflation pressure was set at 5–6 mmHg. The following two 0.5-cm lateral incisions near the mouth’s angle were made to insert the other two 5-mm trocars. The working space was expanded further caudally by a laparoscopic cautery hook and ultrasonic scalpel to reach the sternal notch inferiorly and to the sternocleidomastoid laterally. The strap muscles were divided in the midline in order to expose the thyroid gland. The strap muscle was laterally retracted by a transcutaneous 3-0 silk suture to enhance the working space. The pyramidal lobe is dissected and separated from the trachea and the isthmus. The plane between the gland and cricothyroid muscle is identified for exposing the superior pole vessels. The artery and vein are ligated as close to the thyroid gland as possible to preserve the external branch of the superior laryngeal nerve. The recurrent laryngeal nerve (RLN) and the superior and inferior parathyroid glands are identified and protected. The surgeon performs lobectomy using a harmonic scalpel and preserves the parathyroid glands and the nerve. The thyroid lobe specimen is placed in an endobag and retrieved through the central trocar. The strap muscles are closed. The mucosal incisions were closed with absorbable sutures. No drains were placed.

Statistical analysis

Data were analysed using IBM Corp. Released 2017. IBM SPSS Statistics for Windows, Version 25.0. Armonk, NY: IBM Corp. Continuous variables were presented as mean ± standard deviation and range where appropriate and categorical variables as the number with a percentage. The means were compared using the Mann–Whitney U-test or t-test, and the proportions were compared by Fisher’s exact or Chi-square test when appropriate. All tests were two-tailed, and differences were considered statistically significant at P ≤ 0.05.

RESULTS

In our study of 200 patients, 100 were performed with the TOETVA method and 100 underwent COT. The mean age of the patients was 34.5 ± 7.7, with the TOETVA group being younger than the COT group (32.9 ± 8.1 vs. 36.2 ± 6.9, P = 0.002). Most of the patients were female, with only 18 patients being male. There is no difference in gender between the TOETVA group and the COT group. The mean tumour size in the TOETVA and COT groups is 29.9 ± 6.8 mm and 30.9 ± 6.5 mm, respectively, and the difference is not statistically significant [Table 1].

Table 1.

Patient demographics between transoral endoscopic thyroidectomy vestibular approach and conventional open thyroidectomy group

Variables	TOETVA group (n=100)	COT group (n=100)	Total (n=200)	P
Age (years), mean±SD	32.9±8.1	36.2±6.9	34.5±7.7	0.002
Gender, n (%)
Female	95	94	189	0.756
Male	5	6	11
FNA Bethesda class (%)
Benign	88	84	172	0.415
AUS/FLUS	12	16	28
Tumour size (mm), mean±SD	29.9±6.8	30.9±6.5	30.5±6.6	0.314

TOETVA: Transoral endoscopic thyroidectomy vestibular approach, COT: Conventional open thyroidectomy, FNA: Fine-needle aspiration, AUS/FLUS: Atypia of undetermined significance/follicular lesion of undetermined significance, SD: Standard deviation

In the TOETVA group of 100 patients, 92 underwent thyroid lobectomy and 8 underwent total thyroidectomy. In contrast, in the COT group, 90 patients underwent thyroid lobectomy and 10 underwent total thyroidectomy. There was no difference in surgical extension between the TOETVA and COT groups. The surgical time in the TOETVA group was significantly longer than in the COT group. The operative time of lobectomy in the TOETVA and COT groups was 77.5 ± 13.3 and 51.5 ± 4.2 min, respectively, with a P < 0.001. The operative time of total thyroidectomy in the TOETVA and COT groups was 108.1 ± 7.0 and 65.0 ± 4.1 min, respectively, with a P < 0.001. There was no difference in post-operative length of stay between the two groups [Table 2].

Table 2.

Operative details of the conducted transoral endoscopic thyroidectomy vestibular approach and conventional open thyroidectomy procedures

Variables	TOETVA group (n=100)	COT group (n=100)	Total (n=200)	P
Types of surgery
Lobectomy	92	90	182	0.621
Total thyroidectomy	8	10	18
Operative time (min)
Lobectomy	77.5±13.3	51.5±4.2	64.7±16.4	<0.001
Total thyroidectomy	108.1±7.0	65.0±4.1	84.2±22.7	<0.001
LOS (day)	4.2±0.9	4.1±0.8	4.2±0.8	0.829

TOETVA: Transoral endoscopic thyroidectomy vestibular approach, COT: Conventional open thyroidectomy, LOS: Length of stay

In our study, amongst 100 cases of TOETVA, there were no patients who converted to open surgery. Amongst all 200 patients in the study, there were no cases of post-operative bleeding. The transient hypoparathyroidism rate after surgery in the TOETVA and COT groups was 3% and 2%, respectively, with no statistically significant difference (P = 0.651). Similarly, the transient RLN injury rate showed no difference between the two groups, with rates of 5% and 4% in the TOETVA and COT groups, respectively (P = 0.733). There were no cases of post-operative infection in either group in our study [Table 3]. At 3 months postoperatively, the cosmetic satisfaction were significantly higher in the endoscopic groups than in the conventional group (P < 0.001) [Table 4].

Table 3.

Intraoperative events and post-operative complications

Variables	TOETVA group (n=100), n (%)	COT group (n=100), n (%)	Total (n=200), n (%)	P
Post-operative bleeding	0	0	0
Mental nerve injury
Temporary	12 (12)	0	0
Permanent	0	0	0
Hypoparathyroidism
Temporary	3 (3)	2 (2)	5 (2.5)	0.651
Permanent	0	0	0
RLN injury
Temporary	5 (5)	4 (4)	9 (4.5)	0.733
Permanent	0	0	0
Post-operative infections	0	0	0

TOETVA: Transoral endoscopic thyroidectomy vestibular approach, COT: Conventional open thyroidectomy, RLN: Recurrent laryngeal nerve

Table 4.

Level of satisfaction 3 months after surgery

Variables	TOETVA group (n=100), n (%)	COT group (n=100), n (%)	P
Very satisfied	82 (82.0)	37 (37.0)	<0.001a
Satisfied	10 (10.0)	57 (57.0)
Normal	8 (8.0)	6 (6.0)
Dissatisfied	0	0

^aFisher’s exact test. TOETVA: Transoral endoscopic thyroidectomy vestibular approach, COT: Conventional open thyroidectomy

DISCUSSION

Open surgery is a conventional method for treating benign thyroid tumours when surgery is indicated, but this method leaves a scar on the neck permanently. In 2016, Anuwong reported good outcomes for 60 TOETVA patients, which represented a breakthrough in endoscopic surgery worldwide.[7] Today, TOETVA is increasingly being applied in many thyroid surgery centres worldwide due to its many advantages, such as the ability to access both thyroid lobes, remove central neck lymph nodes and have ideal cosmetic results by leaving no scar on the skin.[8,9,10,11]

In our sample of 200 patients, the mean age of the study group was 34.5 ± 7.7. The mean age of the TOETVA patient group was 32.9 ± 8.1, which was significantly lower than the mean age of the COT group. Overall, patients who choose endoscopic surgery tend to be younger than those who undergo open surgery, as younger patients often desire better cosmetic outcomes. In Anuwong’s study, the mean age was 35.3 ± 12.1.[7] Another study conducted on 412 patients in Brazil reported a mean age of 40 years.[12] Two comparative analyses of the outcomes of TOETVA and COT also showed that the TOETVA patient group was younger than the COT group.[13,14] The majority of our patients were female (94.5%), which is consistent with studies worldwide that indicate that thyroid nodules are more commonly found in women.[15,16]

In our study, 18 patients underwent total thyroidectomy (8 via TOETVA and 10 via COT), while the rest underwent hemithyroidectomy. During the follow-up period from 2018 until now, we have not encountered any patients requiring reoperation due to recurrence in the opposite lobe. Thus, we think that thyroid lobectomy may be an effective therapeutic strategy for unilateral, benign nodules. Compared to COT, TOETVA was reported to have significantly longer operative times. In 100 cases of the TOETVA group, we found that the mean operative time for TOETVA with hemithyroidectomy and total thyroidectomy was 77.5 ± 13.3 min and 108.1 ± 7.0 min, respectively, significantly longer than the COT group. There was no difference in post-operative length of stay between the two groups. These results were consistent with those reported by Anuwong et al. they were faster than the study conducted by Fernández-Ranvier et al., where the operative times for hemithyroidectomy and total thyroidectomy with TOETVA were 157 ± 40.9 min and 217.5 ± 33.3 min, respectively.[7,15] The longer operative time in the TOETVA group compared to the COT group is due to the need for time to create a working space, but the operative time can be improved with experienced surgeons.[17,18]

All patients who underwent TOETVA were successful, with no patients requiring open surgery. The conversion rate to open surgery in studies with large sample sizes ranges from 0% to 5%.[11,19] Conversion to open surgery is usually due to uncontrollable bleeding, huge nodules, or Graves’ disease. Many factors affect the success rate of TOETVA in our study, including the patient selection and the surgeon’s skill. In our study, we selected patients with benign nodules of moderate size. In addition, TOETVA has been implemented since 2018 and successfully performed in over 500 cases, providing a wealth of experience with this technique.

In the TOETVA group, none of the patients required conversion to open surgery. In contrast, the conversion rate to open surgery in studies with large sample sizes ranges from 0% to 5%.[11,19] Conversion to open surgery is usually due to uncontrollable bleeding, huge nodules, or Graves’ disease. Many factors affect the success rate of TOETVA in our study, including patient selection and surgeons’ experience. In our study, we selected patients with benign nodules of moderate size. In addition, TOETVA has been implemented since 2018 and successfully performed in over 500 cases, providing a wealth of experience with this technique.

RLN injury and hypoparathyroidism are common complications after thyroid surgery. In our study, no patient had a permanent RLN injury. The temporary RLN injury rates for the TOETVA and COT groups were 5% and 4%, respectively, with no statistically significant difference (P = 0.651). Fernández-Ranvier et al. also reported similar results in comparing 33 TOETVA patients with 33 COT patients.[15] Furthermore, a meta-analysis showed that the rates of temporary and permanent vocal cord paralysis in 1887 TOETVA patients were 1.9%–8.8% and 0.59%–1.42%, respectively.[19] Regarding hypoparathyroidism, no patient had permanent hypoparathyroidism in our study. We found that only three TOETVA patients and two COT patients had temporary hypoparathyroidism, with no statistically significant difference. Fernández-Ranvier et al. reported a similar 3% rate of temporary hypoparathyroidism in both TOETVA and COT groups.[15] Furthermore, a meta-analysis showed that the temporary and permanent hypoparathyroidism rates in TOETVA were 0.94%–22.2% and 1.33%–2.22%, respectively.[19] Thus, TOETVA is a safe and highly effective surgery.

Some other complications associated with the transoral approach include injury to the mental nerves and infection. In our study, 3 out of 27 patients (11.1%) experienced numbness in the chin and lower lip after surgery but recovered within a month; no patient had an infection. The pooled analysis showed a 5.8% rate of mental nerve injury and a 0.64% (12/1887) infection rate. There was no difference in the infection rate between open surgery and TOETVA.[19]

A visible scar on the anterior neck after conventional thyroid surgery may cause mental distress and affect the quality of life negatively, such as in patients with chronic skin diseases.[20,21] Obviously, as the only remote-access technique that obviates a cutaneous incision, TOETVA eliminates the risk for developing cutaneous scar-related complications including hypertrophic scar and keloid. Thus, transoral thyroidectomy provides significantly enhanced early cosmesis over the transcervical approach.

CONCLUSIONS

TOETVA is a safe and effective method, with a low complication rate and optimal aesthetic results compared to traditional surgery to treat benign thyroid tumours.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.