Transoral thyroid and parathyroid surgery in Brazil: where are we?

ABSTRACT Introduction: thyroid surgery through the transoral vestibular approach is a reality in many countries. While several competing remote access techniques have been developed in the last 20 years, many were not reproducible. Transoral Endoscopic Neck Surgery (TNS) has been shown to be reproducible in different centers around the world, and approximately five years after its description it has been adopted relatively quickly for various reasons. To date, there are at least 7 Brazilian studies published, including a series of more than 400 cases. The aim of this work is to study the progression of Transoral Neck Surgery in Brazil and describe the profile of surgeons involved in this new approach. Methods: this is a retrospective study with descriptive statistics. A REDCap based survey about transoral endoscopic thyroidectomy and parathyroidectomy vestibular approach (TOETVA/TOEPVA) was done with 66 Brazilian surgeons regarding surgeon profile, numbers of cases performed by geographic region, what kind of training was necessary prior to the first case and behavior of the surgeon proposing these new approaches. Results: response rate of this survey was 53%. To date, 1275 TOETVA/TOEPVA cases had been performed in Brazil, 1229 thyroidectomies (96.4%), 42 parathyroidectomies (3.3%) and 4 combined procedures (0.3%). Most of the cases were done in the southeast region (821, 64.4%), 538 (42.2%) cases in the State of São Paulo and 283 (22.2%) cases in the State of Rio de Janeiro. Conclusions: TOETVA is becoming popular in Brazil. Younger surgeons, especially those between 30 and 50 years old were more likely to adopt this approach.


INTRODUCTION
T ransoral thyroid and parathyroid endoscopic surgery through the vestibular approach is a reality in many countries in most parts of the world 1,2 .Several remote access thyroidectomy techniques have been developed in the last 20 years seeking for better cosmetic outcomes 3,4 .Many were not reproducible, and were therefore abandoned 5 .In Brazil, the first series of transoral endoscopic thyroidectomy was published in 2018 by Tesseroli et al. 6 .After that, more and more surgeons have adopted the technique and some have published their results [6][7][8][9][10][11][12] .This procedure is called Trans Oral Endoscopic Thyroidectomy/Parathyroidectomy Vestibular Approach (TOETVA/TOEPVA) by most authors to distinguish it from a previously described transoral technique that used one or more trocars through the floor of the mouth 13 .In this technique, surgical access is made with 3 trocars inserted through the oral vestibule (Figure 1).As such, the technique may be considered a natural orifice endoscopic surgery (NOTES™).Infection and other complications are rare, and the postoperative result is very similar to that of open thyroidectomy, but with the absence of a scar in the anterior neck 3,4,7,8 .
Other remote access thyroid surgery techniques, such as transaxillary, transthoracic and transmammary, are known to increase length of stay, require the systematic use of drains, increase recovery time and can result in serious complications not described in open thyroidectomy 5 .TOETVA demonstrates a safety profile that is similar to that of open surgery regarding complications related to the laryngeal nerves and parathyroid glands 4 .It allows access to both thyroid lobes and the central compartment.When compared to other remote access techniques, TOETVA is a true scarless surgery, as there are no cutaneous incisions.
Of the remote access surgeries, it also represents the shortest route between the entry of the trocars and the thyroid, it doesn't require routine drainage and brings a short length of stay and fast recovery.There is some evidence that there may be less pain with this technique as well [14][15][16] .Therefore TOETVA is considered a minimally invasive approach by some authors, although it may be best referred to as a remote access surgical technique 17 .TOETVA was first described by American surgeons 18 after some experimental studies on animals and cadavers 13,18,19 , but it gained popularity after Anuwong, a surgeon from Thailand, published his first series of 60 cases in 2015, describing encouraging results 4 .The technique has been shown to be reproducible in different centers around the world, and has been adopted quickly 20 , as it requires only regular laparoscopic instruments without adding excessive costs and prohibitive surgical time.
Further, it has been demonstrated to have a relatively short learning curve 8,9 .TOETVA also adds the benefits of videosurgery to thyroidectomy, such as image magnification and the ability to effortlessly record data and technique 3,21 .These video benefits may increase exponentially as artificial intelligence offers potential for surgical landmark assistance in the future.Cosmetically, it has been found to be superior when compared to open thyroidectomy 22,23 .
Although TOETVA/TOEPVA has been adopted in other Latin American countries such as Argentina 25 there is no evidence of the number of patients who have undergone this procedure in Brazil, nor the number of surgeons performing it.There are also some important concerns about the extent of surgical training surgeons are obtaining before starting TOETVA.
The aim of this work is to study the progression of Transoral Neck Surgery in Brazil and describe the profile of surgeons involved in this new approach.

MATERIAL AND METHODS
This is a survey study by descriptive statistics.
A web based survey was designed to describe the characteristics of surgeons performing TOETVA in Brazil.This was then distributed electronically to a working  Final decision between open or endoscopic approach if the patient fits for TOETVA -Surgeon or Patient

RESULTS
The response rate of this survey was 53%, acknowledging that some teams chose to respond to the survey after gathering data from each member.This could result in a lower response rate but one that still reflects a high percentage of eligible participants.are head and neck surgeons, 2.9% (n=2) are oncologic surgeons and 1.6% (n=1) are endocrine surgeons (Table 2).When asked about their participation in real cases of TOETVA/TOEPVA, 30.3% (n=20) participated in up to 5 cases, 37.9% (n=25) in 5 to 25 cases, 13.6% (n=9) in 25 to 50 cases, 4.5% (n=3) in 50 to 75 cases, 6.1% (n=4) in 75-100 cases, 4.5% (n=3) in 100-150 cases and 3% (n=2) had participated in over 150 cases (Table 3).This means that a majority of cases, 86% (n=1101) had been completed by a surgeon who had participated in more than 25 cases.Of note, 30.3% (n=20) of this sample participated as a Proctor in some cases.Trying to understand the individual perception of the learning curve, the surgeons were asked to determine at what case number they became more comfortable with the technique: 28.8% (n=19) said 5 cases, 15.2% (n=10) 10 cases, 15.2% (n=10) 15 cases, 3% (n=2) 20 cases, 1.5% (n=1) 25 cases, 1.5% (n=1) 30 cases, and 34.8% (n=23) said that they are still not comfortable with the technique (Table 3).

DISCUSSION
Transoral neck surgery for thyroid and parathyroid is a new technique and it is being adopted on a worldwide scale, specially in Asia and the Americas the open approach 28 .After a short learning curve of 10 to 15 cases 8,9 surgery time decreases and becomes only slightly longer than open thyroidectomy 8,9 .Despite these findings, there remains some resistance to the technique that does not appear to be supported by the limited complications to date 29 .

Figure 1 .
Figure 1.Image of the surgical access for TOETVA and TOEPVA.

Tenório
Transoral thyroid and parathyroid surgery in Brazil: where are we? in their daily practice 57.6% (n=38) said yes.Among all surgeons, 27.3% (n=18) were already trained in robotic surgery.The majority of surgeons (80.3%, n=53) involved in this sample have had specific TOETVA training, some in cadaver lab and others in animal lab.Those who didn't have specific training were already trained in robotic surgery and some went to the USA or Thailand for training and observerships before starting.Most surgeons (85%, n=56) have watched cases from an experienced colleague before performing their first case.The number of observed cases before beginning the technique varied from 1 to 30 (median: 5).The majority (63.6%, n=42)

Figure 2 .
Figure 2. Number of cases by states.

Figure 3 .
Figure 3 .Number of surgeons by states.
curve.Training background is a critical aspect when starting a new surgical technique.Even with previous videosurgery training, the pioneers of TOETVA in Brazil[6][7][8][9][10][11][12] sought training and observerships in other countries.Some went to the USA and others travelled to Thailand, the first high volume centers of TOETVA in the world.These surgeons have collaborated with each other in their first cases and have also developed the first Brazilian courses about TOETVA, using animal lab and cadaver lab which have allowed other surgeons to train without travelling abroad.The predominant age group between respondent surgeons was 36 to 47 years old, showing that younger surgeons were most likely to adopt TOETVA/TOEPVA.Any new surgical procedure has an initial resistance for various reasons.Most of the adopters have finished their residency at least 5 years prior to initiating TOETVA.Those surgeons learning TOETVA may have had sufficient open cases after these years to advance to remote access techniques, consistent with international recommendations 5 .Tenório Transoral thyroid and parathyroid surgery in Brazil: where are we? also overestimated or underestimated the number of cases and other data submitted.CONCLUSION Transoral Thyroid and Parathyroid Neck Surgery are becoming popular in Brazil.To date, 1275 cases have already been performed in all 5 regions of Brazil and in more than half of the federation units.Young surgeons, especially those between 30 and 50 years old, were more likely to adopt these novel approaches.The personal background of videosurgery, specific TOETVA training, observation of an experienced surgeon and proctorship during the first cases seem to be highlights of those who have adopted the technique.

Table 1 -
Data collected on the REDCap based electronic survey.

Table 2 -
Summary of cases performed and surgeon profile.2%) cases in the State of São Paulo and 283 (22.2%) cases in the State of Rio de Janeiro (Table 2).

Table 2 )
. Their age varied from 30 to 63 years old with a median age of 41 years old.More than 75% were under 50 years old, and the predominant age group was between 36 to 47 years old, representing 50% of the sample.According to the survey 95.5% (n=63)

Table 3 -
Results -Surgeons participation in cases and learning curve.