European Journal of Cardiovascular Medicine

Thyroid hypertrophy, thyroid nodules and thyroid cancers are a major cause of morbidity worldwide [1], and surgical management is often the mainstay of their treatment. Thyroid surgery can be performed using one of about twenty different procedures. In recent years, natural orifice transluminal endoscopic surgery (NOTES) has gotten a lot of attention in the surgical community because it can reduce surgical trauma, tissue damage, and morbidity while also speeding up recovery [2].

More recently, there has been development of a technique known as the transoral endoscopic thyroidectomy vestibular approach (TOETVA). This novel remote-access endoscopic technique for the excision of the thyroid gland has been categorized as a NOTES procedure—given the approach to the thyroid gland via incisions in the oral cavity [3,4]. TOETVA applies the benefits and avoids the drawbacks of the other remote access procedures. There is less tissue dissection and distance to reach the target gland, and there is complete avoidance of a skin incision (with incisions hidden in vestibular mucosa) [4].

However, the transoral endoscopic thyroidectomy has two approaches: sublingual and vestibular. TOETVA is being performed at various international institutions and multiple hospitals. Patients successfully underwent all forms of thyroidectomies including isthmusectomies, lobectomies, subtotal, completion, and total thyroidectomies. Indications for surgery varied from benign symptomatic disease to preoperatively diagnosed malignancy, and also included nodules classified as Bethesda classes 2 through [2]. There were reported cases that required conversion to an open procedure, due to excessive bleeding, underestimated preoperative nodular/goiter size, or substernal extension of the thyroid gland appreciated intra-operatively [5].

Injury to the recurrent laryngeal nerve is a complication that still persists in traditional transcervical thyroidectomies. With advances in the endoscopic vestibular approach technique there has been a low incidence of RLN injury. In all reported cases of injury to the RLN, via TOETVA, a full recovery of vocal cord function was reported within 6 months of surgery. As in traditional transcervical thyroidectomy, hypocalcaemia is more common when a total thyroidectomy is performed. Fortunately, there have been no reports of permanent hypoparathyroidism [6].

Due to its advantages, including complete healing without scar, reduced operation time and range of dissection, and a short learning curve, TOETVA has been reported to be an ideal minimally invasive thyroidectomy technique. However, few large-scale studies have been conducted, especially for thyroid swelling in this part [7, 8]. Therefore, the present study was conducted to elucidate whether the technique of transoral video-assisted endoscopic thyroidectomy is safe and feasible modality which can be used regularly for the treatment of benign thyroid pathologies.

After obtaining Institutional Ethical Committee approval and written informed consent from all the patients, this prospective observational study was carried out in the Department of Surgery at tertiary care hospital during a period from October 2019 to September 2021. A total sample size of 40 patients with benign thyroid disease (proven on imaging and cytology), nodules' maximum diameter <5 cm, the total thyroid volume was ≤45 mL with no lymph node metastasis and patient giving consent for the study were included. Patients with history of neck surgery or radiotherapy, recurrent disease and presence of intraoral infection were excluded from the study.

Surgical Procedure

The patients were placed in supine position for the surgery, with a pillow placed below the shoulder and head ring to maintain neck extension (the chin and xiphisternum were maintained at the same plane). The chief surgeon remained at the head end of the table. The camera surgeon was on the left side of the chief surgeon and the second assistant occupied the right side of the surgeon. A monitor was placed on the table between the legs. All patients received general anaesthesia. Endotracheal intubation was done through nasal route. The oral cavity was cleaned with 0.9% normal saline. The gland was approached through the inferior vestibule of the oral cavity. 10 mm incision was made in the midline after usage of Normal saline for hydro-dissection. A specially designed dilator was used to create space followed by which CO2 insufflation was done and 10 mm camera port was inserted (as practiced in hernia surgery). CO2 insufflation was maintained at 6 mmHg. Two 5 mm working ports were introduced in front of the canine tooth on both sides, under endoscopic visualisation. The subplatysmal plane was entered and dissected to create the working space. A Ligasure was used to cut the vessels. The deep fascia was opened in the midline, and the strap muscles retracted externally on either side using 2–0 Ethilon. Subsequently, we identified the superior and inferior pedicles on either side along with the isthmus. Middle thyroid vein, superior thyroid artery and vein were sealed close to the thyroid gland. Utilising the magnified view through the endoscope, the recurrent laryngeal nerve was identified easily and preserved on either side. All four parathyroid glands were identified and preserved. Depending on open/hemithyroidectomy, isthumus was cut. Complete haemostasis was achieved. The entire lobe was brought out through the oral cavity using a custom-made endobag (ethylene oxide- sterilised polyethylene bag), through the 10 mm port. The specimen sometimes needed morcellation before removal and placed into the endobag, under the guidance of the 5 mm scope. A Jackson Pratt drain was placed using the 3 mm port into the lateral side of neck. Strap muscles were re-approximated, and the deep fascia closed in layers using absorbable sutures. The oral vestibular surgical wound was closed using absorbable sutures. A pressure dressing was applied over the chin and neck for 24 h. All patients resumed an oral diet on the first post-operative day, received three doses of intravenous cefazolin (1 g, every 8 h) and continued oral rinse with chlorhexidine solution.

Statistical Methods

The data collected in the study was analysed using statistical package for the social sciences (SPSS) software for windows version 23. A p value <0.05 was considered statistically significant.

A total of 40 patients with benign thyroid pathologies were studied during a study period from October 2019 to September 2021. Majority of patients were in age group of 31-40 years (30%). The mean age of the patients was 42.45±12.75 years with female predominance (70%) as shown in table 1.

Table 1: Demographic profile of the patients

Most of the patients came for neck nodule (cosmetic) reason (65%) followed by hypothyroidism (20%) and hyperthyroidism (15%). Among 40 patients, no mass effect as chief complaints was present. Majority of patients had duration <6 months (50%) followed by 6 months-1 year (30%) as shown in table 2.

Table 2: Distribution according to chief complaints and duration of symptoms

From the figure 1 it was observed that majority of patients diagnosed as multinodular goitre (30%), followed by single thyroid nodule and cyst (27.5%) and grave’s disease (15%).

TOETVA procedure: - majority of patients undergone hemithyroidectomy (22; 55%) followed by total thyroidectomy (18; 45%).

The mean intra-operative blood loss was more, and the mean operative time was longer in total thyroidectomy patients than in the hemithyroidectomy as shown in table 3. In all patients IONM was used (100%). Out of 40, 2 (5%) patient was converted to open thyroidectomy. One because of bleeding and one because of fibrosis.

Table 3: Distribution according to intra-operative blood loss and operative time

Hypoparathyroidism (20%) was the most common post-operative complication which was temporary and resolve in 3 months. Recurrent laryngeal nerve paresis due to neuropraxia was seen in 2 (5%) patients, (Table 4).

Table 4: Rate of complications associated with the procedure.

The mean post-operative pain gradually decreases from day 1 (3.40±1.2) to day 3 (0.40±0.60) with statistically significant difference, (p<0.0001) (Figure 2). The mean hospital stay among patients was 2.48±1.28 days with range of 1 day to 6 days. The mean follow-up among patients was 2.15±1.02 weeks with ranged from 1 to 4 weeks.

T3, T4, TSH and PTH shows no statistically significant difference pre and post operatively, (P>0.05) as shown in table 5.

Table 5: Distribution according to thyroid profile and PTH

Figure 1: Distribution according to diagnosis

Figure 2: Distribution according to post-operative pain (VAS score)

After the first endoscopic parathyroidectomy had been performed by Gagner in 1996 [9], different endoscopic methods (axillary, breast areola, retro-auricular, anterior chest approach, etc.) were defined for benign thyroid nodules and certain differentiated thyroid cancers [10, 11]. Nowadays TOETVA has become attractive to thyroid surgeons and patients around the world because it addresses the desire for minimally invasive surgery and enhanced aesthetic outcomes. Numerous studies have published encouraging results [6, 7, 12, 13]. The present observational study was conducted regarding the use of TOETVA as a modality for the treatment of thyroid swellings with total sample size of 40 patients with benign thyroid pathologies. The mean age of the patients was 42.45±12.75 years with female predominance (70%) which is comparable with the study done by Dinç B et al [14] and Chai YJ et al [15]. In the present study, the mean intra-operative blood loss in hemithyroidectomy was 7.72±2.57 ml while in total thyroidectomy it was 27.01±4.57 ml. The mean operative time of surgery in hemithyroidectomy was 46.36±12.16 minutes while in total thyroidectomy was 77.22±18.08 minutes. These findings are comparable to other reports of initial TOETVA experience [14-16]. Furthermore, the TOETVA complication rates in this study were in line with acceptable rates following open thyroidectomy [17].

A major concern with the transoral approach has been the risk of a surgical-site infection. The mucosa of the oral cavity is colonized with a diverse bacterial flora, including gram-positive aerobic and anaerobic bacteria. To combat the risk of surgical site infection, appropriate preoperative prophylactic antibiotic coverage is recommended to cover against the polymicrobial flora of the mouth [6].

The mental nerve (MN) is a branch of the posterior trunk of the inferior alveolar nerve originating from the mandibular nerve. One of the major concerns in TOETVA is MN injury, which causes numbness and paresthesia in the chin or lower lip, impairing quality of life [18]. Possible causes of MN injury include (a) incorrect vestibular incision and dissection; (b) imprecise port insertion and removal; (c) over-stretching and longer compression of trocars on the MN; and (d) anatomic variations of MN. To protect the MN, surgeons should have a detailed anatomical knowledge of the MN, including its possible variations, and manipulation should be carefully performed during the operation [19]. Others observed MN injury in 1 to 5% of TOETVA cases [19, 20]. In the current study, MN injury was seen in one patient. To prevent MN injury, vestibular incision and port insertion methods were standardized for accuracy and precision, and tension on the MN was minimized by avoiding over-stretching of the lateral two ports.

According to the literature, the prevalence of temporary and permanent hypoparathyroidism in open surgery is from 0.3% to 49% and from 0% to 13%, respectively [21, 22]. On the other hand, in TOETVA, temporary hypoparathyroidism has been observed in two (3.3%) of the 60 patients in the study by Anuwong [23] and in one (6.6%) of the 15 patients in the study by Dionigi et al [24]. Permanent hypoparathyroidism has been identified in neither one of these two studies. In present study, temporary hypoparathyroidism was detected in 8 (20%) patients which is comparable with the study conducted by Dinç B et al [14] and Chai YJ et al [15]. While permanent hypoparathyroidism was detected in none of the patients. In our opinion, the reason for the high rate of temporary hypoparathyroidism is that this was our first experience.

Although an endoscopic approach provides an excellent magnified view of the RLN, there is concern about the increased risk of RLN injury during TOETVA compared to open thyroidectomy. The mechanisms for RLN injury in TOETVA include (a) surgeon’s unfamiliarity with the cranio-caudal view and endoscopic instruments; (b) limited landmarks for RLN identification and modalities for nerve dissection; and (c) insufficient countertraction [25]. In the current study, RLN paresis due to neuropraxia was seen in 2 (5%) patients which is comparable with the study done by Dinç B et al [14]. However, several studies found the overall incidence of RLN injury of 3.1–5.9% for TOETVA to be comparable to the incidence of 2.1–11.8% for open thyroidectomy [26-28]. The low incidence of RLN injury in TOETVA can be explained by the reduced incidence of traction injury and the use of IONM [27, 29]. During TOETVA, the RLN is usually identified at its insertion site and released first after division of the Berry’s ligament. This reduces the risk of traction injury. In the current study, IONM was used in all cases, this is comparable to the literature [26, 28].

There are some limitations of this study. The sample size included in present study was small.  This is a single center study; it has limited generalizability for representing the surgical safety of TOETVA. The short follow-up period does not allow evaluation of long-term oncological outcomes. Additionally, there were few published articles on TOETVA. Therefore, the average values of previous studies still do not have a standard value and the outcomes of the literature are heterogenic. Long-term follow-up studies of oncological outcomes are needed to assess the safety and benefits of TOETVA.

The present study concludes that, TOETVA is the best aesthetic option for thyroidectomy. It is a scarless approach with excellent cosmetic outcomes, which provides equal accessibility to either lobe without the need for an additional port. However, TOETVA is a safe and feasible technique with acceptable complication rates and good outcomes. More research, particularly using newly developed tools to further improve this technique, are needed, thus making it more available to patients worldwide

1. Scerrino G, Inviati A, Di Giovanni S, Paladino NC, Di Paola V, Re GL, et al. Esophageal motility changes after thyroidectomy; possible associations with postoperative voice and swallowing disorders: preliminary results. Otolaryngol Head Neck Surg. 2013;148:926–932.
2. Camenzuli C, SchembriWismayer P, CallejaAgius J. Transoral Endoscopic Thyroidectomy: A Systematic Review of the Practice So Far. JSLS. 2018;22(3):e2018.00026.
3. Richmon JD, Holsinger FC, Kandil E, Moore MW, Garcia JA, Tufano RP. Transoral robotic-assisted thyroidectomy with central neck dissection: preclinical cadaver feasibility study and proposed surgical technique. J Robot Surg. 2011;5:279–82.
4. Benhidjeb T, Wilhelm T, Harlaar J, Kleinrensink GJ, Schneider TA, Stark M. Natural orifice surgery on thyroid gland: totally transoral video- assisted thyroidectomy (TOVAT): report of first experimental results of a new surgical method. Surg Endosc. 2009;23:1119–20.
5. Fernandez-Ranvier G, Meknat A, Guevara DE, Inabnet WB 3rd. Transoral Endoscopic Thyroidectomy Vestibular Approach. JSLS. 2019;23(4):e2019.00036.
6. Anuwong A, Sasanakietkul T, Jitpratoom P, Ketwong K, Kim HY, Dionigi G, et al. Transoral endoscopic thyroidectomy vestibular approach (TOETVA): indications, techniques and results. Surg Endosc. 2018; 32:456–65.
7. Anuwong A., Kim H.Y., Dionigi G. Transoral endoscopic thyroidectomy using vestibular approach: Updates and evidence. Gland Surg. 2017;6:277–284.
8. Lira RB, Ramos A.T., Nogueira R.M.R., De Carvalho G.B., Russell J.O., Tufano R.P., Kowalski L.P. Transoral thyroidectomy (TOETVA): Complications, surgical time and learning curve. Oral Oncol. 2020; 110:104871.
9. Gagner M. Endoscopic subtotal parathyroidectomy in patients with primary hyperparathyroidism. Br J Surg 1996; 83: 875.
10. Li ZY, Wang P, Wang Y, Xu SM, Cao LP, Que RS. Endoscopic thyroidectomy via breast approach for patients with Graves’ disease. World J Surg 2010; 34: 2228-32.
11. Lee KE, Kim HY, Park WS, Choe JH, Kwon MR, Oh SK, et al. Postauricular and axillary approach endoscopic neck surgery: a new technique. World J Surg 2009; 33: 767-72.
12. Lira RB, Ramos AT, Nogueira RMR, De Carvalho GB, Russell JO, Tufano RP, Kowalski LP. Transoral thyroidectomy (TOETVA): Complications, surgical time and learning curve. Oral Oncol. 2020:110;104871.
13. Chai YJ, Kim HY, Kim HK, Jun SH, Dionigi G, Anuwong A, Richmon JD, Tufano RP. Comparative analysis of 2 robotic thyroidectomy procedures: Transoral versus bilateral axillo-breast approach. Head Neck 2018;40:886–892.
14. Dinç B, İlker Turan M, Rıza Gündüz U, Haluk Belen N. Transoral endoscopic thyroidectomy vestibular approach (TOETVA): Our outcomes from Turkey. Turk J Surg. 2020 Dec 29;36(4):340-346. 
15. Chai YJ, Chae S, Oh MY, Kwon H, Park WS. Transoral Endoscopic Thyroidectomy Vestibular Approach (TOETVA): Surgical Outcomes and Learning Curve. Journal of Clinical Medicine. 2021; 10(4):863.
16. Russell JO, Razavi CR, Shaear M, Liu RH, Chen LW, Pace-Asciak P, Tanavde V, Tai KY, Ali K, Fondong A et al. Transoral Thyroidectomy: Safety and Out-comes of 200 Consecutive North American Cases. World J. Surg. 2020:45;774–781.
17. Lang BH.-H, Wong CKH, Tsang JS, Wong KP, Wan KY. A Systematic Review and Meta-analysis Comparing SurgicallyRelated Complications between Robotic-Assisted Thyroidectomy and Conventional Open Thyroidectomy. Ann. Surg. Oncol. 2013:21;850–861.
18. Pino A, Parafioriti A, Caruso E, De Pasquale M, Del Rio P, Calò PG, Dionigi G, D’Alcontres FS. What You Need to Know about Mental Nerve Surgical Anatomy for Transoral Thyroidectomy. J. Endocr. Surg. 2019;19:144–150.
19. Zhang D, Famá F, Caruso E, Pinto G, Pontin A, Pino A, Mandolfino T, Gagliano E, Siniscalchi EN, De Ponte FS et al. How to Avoid and Manage Mental Nerve Injury in Tran-soral Thyroidectomy. Surg. Technol. Int. 2019;35:101–106.
20. Zhang D, Wu CW, Inversini D, Kim HY, Anuwong A, Bacuzzi A, Dionigi G. Lessons Learned from a Faulty Transoral En-doscopic Thyroidectomy Vestibular Approach. Surg. Laparosc. Endosc. Percutan. Tech. 2018;28:e94–e99.
21. Wiseman JE, Mossanen M, Ituarte PHG, Bath JMT, Yeh MW. An algorithm informed by the parathyroid hormone level reduces hypocalcemic complications of thyroidectomy. World J Surg 2010; 34: 532-7.
22. Makay O, Unalp O, Icoz G, Akyildiz M, Yetkin E. Completion thyroidectomy for thyroid cancer. Acta Chir Belg 2006; 106: 528-31.
23. Anuwong A. Transoral endoscopic thyroidectomy vestibular approach: a series of the first 60 human cases. World J Surg 2016; 40: 491-7.
24. Dionigi G, Bacuzzi A, Lavazza M, Inversini D, Boni L, Rausei S, et al. Transoral endoscopic thyroidectomy: preliminary experience in Italy. Updates Surg 2017; 69: 225-34.
25. Zhang D, Sun H, Tufano R, Caruso E, Dionigi G, Kim HY. Recurrent laryngeal nerve management in transoral endo-scopic thyroidectomy. Oral Oncol. 2020;108:104755.
26. Anuwong A, Ketwong K, Jitpratoom P, Sasanakietkul T, Duh Q.-Y. Safety and Outcomes of the Transoral Endoscopic Thyroidectomy Vestibular Approach. JAMA Surg. 2018;153:21–27.
27. Erol V, Dionigi G, Barczy ´nski M, Zhang D, Makay Ö. Intraoperative neuromonitoring of the RLNs during TOETVA procedures. Gland. Surg. 2020;9:S129–S135.
28. Chen S, Zhao M, Qiu J. Transoral vestibule approach for thyroid disease: A systematic review. Eur. Arch. Oto-Rhino-Laryngol. 2019;276:297–304.
29. Kim HY, Liu X, Wu CW, Chai YJ, Dionigi G. Future Directions of Neural Monitoring in Thyroid Surgery. J. Endocr. Surg. 2017;17:96–103.