Customized Treatment of Graves' Disease by Transoral Endoscopic Thyroidectomy Vestibular Approach: A Retrospective Cohort Study with Long-term 
Follow-up

doi:10.21203/rs.3.rs-5339251/v1

Purpose

Graves' Disease (GD) management often requires surgical intervention when medical therapy fails. The Transoral Endoscopic Thyroidectomy Vestibular Approach (TOETVA) has emerged as a promising scarless technique. This study evaluates the efficacy, safety, and cosmetic outcomes of customized TOETVA techniques in GD treatment.

Methods

We conducted a retrospective analysis of 33 GD patients who underwent TOETVA between January 2019 and March 2024. Patients received one of three procedures: Total Thyroidectomy (TT, n = 11), bilateral Subtotal Thyroidectomy (ST, n = 7), or Dunhill procedure (Dh, n = 15). Outcomes were assessed over a 6–69 month follow-up period.

Results

TT and Dh were significantly more effective in preventing recurrent hyperthyroidism compared to ST (0/26 vs. 4/7, p < 0.006). The Dh group showed a higher incidence of postoperative hypothyroidism than ST (13/15 vs. 2/7, p < 0.001). Temporary hypoparathyroidism was more common in the TT group (3/11 vs. 0/22, p = 0.037). Intraoperative blood loss was significantly higher in the ST group (175.71 ± 299.38 ml) compared to Dh (27 ± 61.99 ml) and TT (4.91 ± 3.24 ml) groups (p < 0.001). No permanent hypoparathyroidism or recurrent laryngeal nerve injuries were observed.

Conclusion

Customized TOETVA for GD demonstrates safety and efficacy, with TT and Dh showing superior outcomes in preventing recurrent hyperthyroidism. The choice of technique should be tailored to individual patient factors, balancing the risks of recurrence and postoperative thyroid dysfunction.

Surgery

Graves’ disease

TOETVA

thyroidectomy

hyperthyroidism

Graves' Disease (GD) is an autoimmune disorder characterized by hyperthyroidism due to circulating autoantibodies. While antithyroid drugs (ATD) are typically the first-line treatment, surgery remains a crucial therapeutic option for many patients, especially those with large goiters, ATD intolerance, or failed medical management[1].

Traditional thyroidectomy approaches have been associated with visible scarring, which can be a significant concern for patients, particularly given the predominance of GD in younger females. The Transoral Endoscopic Thyroidectomy Vestibular Approach (TOETVA) has emerged as an innovative technique offering the potential for scarless surgery [2]. This approach not only addresses cosmetic concerns but also potentially reduces postoperative recovery time.

However, the optimal extent of thyroid resection in GD remains controversial, with options ranging from total thyroidectomy (TT) to various forms of bilateral subtotal thyroidectomy (ST) or Dunhill procedure (Dh) [3]. Each approach carries its own risk-benefit profile in terms of recurrence rates, postoperative thyroid function, and complication risks.

This study aims to evaluate the application of customized TOETVA techniques in the treatment of GD, focusing on three specific approaches: TT, ST, and the Dh. We investigate the safety, efficacy, and cosmetic outcomes of these techniques, tailored to patients' individual requirements and conditions.

Study Design and Patient Selection

We conducted a retrospective analysis of 33 GD patients who underwent TOETVA between January 2019 and March 2024. Patients were selected based on their diagnosis of GD and suitability for the TOETVA approach. The clinical research was also approved by the Institutional Review Board of our hospital and was conducted in accordance with the Declaration of Helsinki. The exclusion criteria were previous neck surgery and any suspicion of thyroid malignancy.

The goiter size was identified by palpation and classified into four grades: grade 0, no palpable goiter; grade 1, a palpable goiter not reaching the medial edge of the sternocleidomastoid muscle; grade 2, a palpable goiter reaching the sternocleidomastoid muscle but not exceeding the lateral edge; and grade 3, a palpable goiter exceeding the lateral edge of the sternocleidomastoid muscle [4].

Surgical Techniques

Patients underwent one of three TOETVA procedures:

TT: Complete removal of both thyroid lobes and the isthmus.
ST: Partial resection of both thyroid lobes, leaving partial thyroid tissue on each side.
Dh: Total lobectomy on one side and subtotal resection on the contralateral side.

The choice of procedure was based on individual patient factors, including disease severity, goiter size, and patient preference. All procedures were performed by a single experienced endocrine surgeon to minimize operator-dependent variables.

In some cases, preoperative selective embolization of the thyroid artery (SETA) or intraoperative radiofrequency ablation (RFA) was employed to manage large or hyper-vascular goiters. The intraoperative blood loss (IOBL) was measured by suction bottle or gauze weight. All the specimens were fragmented inside the plastic bags, and then removal from oral incisions. Whether TOETVA was combined with preoperative selective embolization of the thyroid artery (SETA), intraoperative radiofrequency ablation (RFA), or postoperative radioactive iodine therapy (RAI), the postoperative placement of drainage tubes and hospital stays were recorded. Drainage tube removal occurred when there was less than 30 mL/day of drainage. The choice of procedure was based on individual patient factors, including disease severity, goiter size, and patient preference.

Perioperative care. Serum calcium and phosphate levels were checked every 12 h until stabilization. Patients who could discontinue calcium plus vitamin D analog supplements in the presence of normocalcemia (normal, 8.0–10.0 mmol/L) within 6 months after surgery were considered to have temporary hypoparathyroidism, whereas those who continued for > 6 months, along with below-normal serum parathyroid hormone levels (normal, 15–80 pg/mL) were considered to have permanent hypoparathyroidism. An oral thyroxine supplement was prescribed on the day of discharge for hormonal replacement, depending on the patient’s age and body weight if TT was performed. Antibiotics were routinely prescribed, as previously published

Data Collection and Follow-up

Demographic and clinical data were collected for all patients. The follow-up period exceeded 6 months for all participants, ranging from 6 to 69 months. We assessed outcomes including recurrent hyperthyroidism, hypothyroidism, hypoparathyroidism, IOBL, and length of hospital stay. The thyroid functional status and goiter size were measured periodically, usually at 1–2 months after surgery, then every 3–6 months. Failure of treatment was defined as a recurrence of hyperthyroidism at 6 months, requiring either long-term ATD therapy, a repeat dose of RAI, or thyroidectomy. Conversely, successful treatment was defined as a euthyroid or hypothyroid status with a normal-looking neck at 6 months. When the patients presented with hypothyroidism under thyroxine replacement, they received long-term follow-up at least every 3 months. Other complications were also recorded. Remnant thyroid volume was assessed using ultrasound imaging at 3 months postoperatively, employing the ellipsoid volume formula [5].

Statistical Analysis

Numerical variables are expressed as mean ± standard deviation or median (range). A one-way analysis of variance F-test along with a post-hoc Tukey test for multiple comparisons was used to specify potential differences. Additionally, the nonparametric Kruskal–Wallis test was used to verify the analysis of variance F-test results. Categorical data in the form of rates or proportions were compared using Fisher’s exact or chi-square tests. Differences were considered significant if the one-tailed p-value was < 0.05. Statistical analysis was performed using SPSS software v.20 (SPSS, Chicago, IL).

Patient Demographics

A total of 33 patients were included in the study: 11 in the TT group, 7 in the ST group, and 15 in the Dh group. Patient demographics and preoperative characteristics are summarized in Table 1. The Dh group was significantly younger than the TT group (p = 0.003). The duration of preoperative ATD treatment was significantly longer in the ST group compared to the Dh group (p = 0.01).

The goiter size in the 3 groups were not significant, 1 grade 0, 1 grade 1, 7 grade 2, 2 grade 3 in TT; 4 grade 2, 3 grade 3 in ST; 1 grade 1, 12 grade 2, 2 grade 3 in Dh (p = 0.597). The indications for surgery included 9 patients intolerance to ATD, 5 failure after I-131 RAI, 2 preference and 20 due to cosmetic and airway compression syndrome.

Procedure Distribution

Operative Outcomes

Operative details and immediate postoperative outcomes are presented in Table 2. IOBL was significantly higher in the ST group compared to both TT and Dh groups (p < 0.001). The ST group also had a longer mean hospital stay (p < 0.001). There were no complications for re-bleeding or infection.

Preoperative SETA was utilized in 9 patients in TT, 5 ST and 15 Dh. Intraoperative RFA was performed 7 patients in ST and 1 Dh. The resection weight of thyroid gland was 57.69 ± 22.25 gm for TT, 36.79 ± 4.62 gm for ST, and 72.94 ± 23.90gm for Dh (p = 0.001). Postoperative drainage tubes were placed 3 in ST group and 1 in Dh. The TT group had no placement of any drainage tube.

All patients reported high satisfaction with the cosmetic outcomes of TOETVA, with no visible neck scars.

Postoperative Long-term Results

All these patients were follow-up periods ranged from 6 to 69 months. Table 3 summarizes the long-term outcomes and complications. The TT group showed a higher incidence of temporary hypoparathyroidism (p = 0.037). No cases of permanent hypoparathyroidism or recurrent laryngeal nerve injury were observed in any group. Recurrent hyperthyroidism was significantly more common in the ST group (p = 0.006), with 4 patients requiring additional RAI treatment. Conversely, postoperative hypothyroidism was more prevalent in the TT and Dh groups (p < 0.001).

In the ST and Dh groups, thyroid remnant volume was assessed at 3 months postoperatively. The mean total remnant volume was significantly larger in the ST group (4.99 ± 1.74 ml) compared to the Dh group (2.39 ± 0.36 ml, p < 0.001).

Our study demonstrates that customized TOETVA, combining preoperative SETA, TOETVA, and RFA, can be effectively tailored for thyroid gland resection as our previous report [6]. Each technique offers distinct advantages and challenges. Several key points emerge from our findings.

Efficacy and Recurrence

Both TT and Dh demonstrated superior outcomes compared to ST in preventing recurrent hyperthyroidism. This finding aligns with previous studies that report higher recurrence rates associated with ST [3]. The increased recurrence observed in the ST group may be attributed to the larger volume of residual thyroid tissue, which allows for the potential reactivation of the autoimmune process.

As anticipated, the TT group consistently required lifelong thyroid hormone replacement. The Dh group exhibited a high rate of postoperative hypothyroidism, indicating that the remnant tissue from this procedure may often be insufficient to maintain euthyroidism. Although the ST group had the highest rate of euthyroidism, this came at the cost of an increased risk of recurrence. Nonetheless, hypothyroidism is generally considered preferable to hyperthyroidism, as it is easier to manage, while hyperthyroidism is associated with significant morbidities, including cardiovascular diseases and osteopenia [7]. One female patient in the ST group was initially euthyroid six months post-surgery; however, she experienced a relapse of hyperthyroidism following Trastuzumab-associated chemotherapy for breast cancer. The incidence of such relapses has been reported to range from 0.3–18% [8–10]. She ultimately achieved remission after three months of antithyroid drug (ATD) treatment, receiving 5 mg of methimazole daily.

Surgical Complications

The higher rate of temporary hypoparathyroidism in the TT group is consistent with the more extensive dissection required in this procedure. However, the absence of permanent hypoparathyroidism and recurrent laryngeal nerve injuries across all groups suggests that TOETVA, when performed by experienced surgeons, can achieve complication rates comparable to conventional thyroidectomy[11].

Our combined approach of SETA and RFA proved effective in managing IOBL, particularly in patients with hypervascular thyroid glands[6]. This strategy addresses one of the primary challenges in thyroidectomy for patients with GD, where the hypervascular nature of the thyroid gland complicates hemostasis[12]. It is advisable to prepare for blood transfusions in GD patients with large goiters [12]. Given that TOETVA is a minimally invasive procedure performed in a confined space, any bleeding can obstruct and obscure the operative field. Thus, maintaining a clear surgical view is essential in this endoscopic technique. Our combination of SETA, aimed at reducing blood flow, and RFA, used for hemostasis and tissue destruction, addresses these concerns.

The objective of SETA is to occlude most of the blood supply to the thyroid gland. Anatomically, the thyroid gland receives blood from two bilateral superior and two bilateral inferior arteries, with over 70% of its blood supply coming from the bilateral superior arteries. Therefore, we embolized two to three of these thyroid arteries, effectively diminishing blood supply and IOBL during surgical resection. Some reports have utilized SETA solely for the treatment of GD [13, 14]. However, SETA differs significantly from surgical techniques such as ST or Dh, where tissue is excised and removed, leaving only a small portion of the thyroid to maintain function. In contrast, when using SETA alone, the embolized thyroid tissue is not removed from the body and can continue to interact with surrounding tissues, potentially leading to autoimmune responses mediated by circulating autoantibodies. This may explain the higher recurrence rates of hyperthyroidism and the lack of long-term follow-up in these cases.

Initially, we did not employ SETA to reduce blood flow; instead, we adhered to traditional methods using ATD to maintain euthyroidism for at least one month, alongside iodine solutions administered 14 days before surgery. In the ST group, two patients who did not receive SETA experienced significant blood loss, with one case reaching up to 800 ml. We subsequently revised our strategy by utilizing Doppler ultrasonography to assess vascularity of the thyroid gland. If hypervascularity was detected, pre-operative SETA was arranged; if no hypervascularity and euthyroid status were observed, pre-operative SETA was not performed.

The higher rate of temporary hypoparathyroidism in the TT group is consistent with the more extensive dissection required in this procedure. However, the absence of permanent hypoparathyroidism and recurrent laryngeal nerve injuries across all groups suggests that TOETVA, when performed by experienced surgeons, can achieve complication rates comparable to conventional thyroidectomy [15].

Recent reports have also discussed the use of RFA for GD [16]. However, the long-term efficacy and outcomes in patients with smaller volumes of thyroid gland remain questionable [16]. In our approach, we utilized RFA primarily for hemostasis and tissue destruction during our combined approach of TOETVA, rather than as the main treatment modality.

Surgery first after ATD control of thyroid function

Less than 30% of young patients achieve lasting remission after at least two years of ATD[7]. Radioactive iodine (RAI) therapy for patients with Graves' disease (GD) has a success rate of only 70.9%, and for patients with grade 3 goiter, the success rate drops to 55% [4]. Furthermore, the success rates at 1, 3, 5, and 10 years are 37.1%, 48.6%, 55.6%, and 65.0%, respectively [4]. Achieving a 50% remission rate with RAI typically requires a duration of at least 3 to 5 years. Another downside of RAI therapy is its potential to induce primary hyperparathyroidism, exacerbate Graves' ophthalmopathy (GO), and lead to reproductive dysfunction or malignancy in a dose-dependent manner [17, 18]. Both ATD and RAI require prolonged treatment for hyperthyroidism, which can negatively impact working ability, socioeconomic status, and contribute to agoraphobia in adults [19]. In children and teenagers, hyperthyroidism can lead to cardiovascular disorders, psychomotor disabilities, osteopenia, or growth retardation [7].

We recommended 7 mCi of low-dose RAI as an adjunct treatment for 4 patients in the ST group due to persistent hyperthyroidism three months after TOETVA surgery. All 4 patients achieved either euthyroidism or hypothyroidism within six months. Employing RAI as an adjuvant treatment post-surgery is a valuable alternative for preventing complications associated with a second operation[20].

Common indications for thyroidectomy include patient preference, noncompliance with medication or RAI regimens, suspicious nodules or known cancer, larger glands causing obstructive or compressive symptoms, or GO. Surgery should be recommended as the first-line or definitive treatment for GD after ATD control of thyroid function due to its rapid recovery and low recurrence rate. RAI can serve as an adjunct to prevent the need for a second operation. Additionally, TOETVA offers a minimally invasive, scar-free surgical option, which is particularly beneficial for the predominantly young or female patient population affected by GD[21].

Customized Approach

* Our findings support a customized approach to surgical management of GD:

For patients prioritizing definitive control of hyperthyroidism, TT is recommended due to its lower recurrence rate, minimal risk of malignant transformation in residual tissue and less chance of worsening GO [1, 3].
For younger patients or those prioritizing the possibility of avoiding lifelong thyroid hormone replacement, the Dh technique with a thyroid remnant of 2-4g may be considered[20].
ST should be approached with caution due to higher recurrence rates and longer hospital stays. It may be considered in cases of incomplete preoperative SETA to minimize the risk of massive IOBL. If hyperthyroidism persisted or recurred following surgery, the RAI could be a salvage postoperatively.

Limitations and Future

Our study has several limitations:

The retrospective design and relatively small sample size limit the generalizability of our findings.
The non-randomized allocation of patients to different surgical techniques introduces potential selection bias.
The follow-up period may not capture very late recurrences or long-term quality of life outcomes.

Future research directions should include:

Prospective, randomized studies with larger cohorts and longer follow-up periods.
Investigation into techniques to further reduce IOBL and hospital stay, particularly in ST cases.
Long-term quality of life assessments comparing different surgical approaches.

Our customized TOETVA approach for GD demonstrates safety and efficacy comparable to conventional thyroidectomy approaches, with the added benefit of superior cosmetic outcomes. Total thyroidectomy and the Dunhill procedure appear to offer the best balance of recurrence prevention and complication risk, albeit at the cost of a high likelihood of postoperative hypothyroidism.

The choice of surgical technique should be tailored to individual patient factors, including age, goiter size, and preference regarding postoperative thyroid function management. Our combination method of preoperative SETA, TOETVA, and selective use of RFA offers a promising approach to managing the challenges associated with thyroidectomy in GD patients, particularly in terms of IOBL control.

Future research should focus on refining these techniques and assessing long-term outcomes to further optimize the management of GD.

Data Availability Statement

The data that support the findings of this study are available from the corresponding author upon reasonable request. Due to privacy and ethical concerns, the data are not publicly available.

Funding Statement

This research was non-funded.

Conflict of Interest Disclosure

The authors declare no conflict of interest.

Ethics Approval Statement

This study was conducted in accordance with the Declaration of Helsinki, and the protocol was approved by the Ethics Committee of Kaohsiung Chang Gung Memorial Hospital, approval number [No 202101890B0]

Patient Consent Statement

Informed consent was obtained from all subjects involved in the study. Written informed consent has been obtained from the patients to publish this paper.

Permission to Reproduce Material from Other Sources

Permission to reproduce figures, tables, or content from other sources has been obtained from the copyright holders.

Smithson M, Asban A, Miller J, Chen H (2019) Considerations for Thyroidectomy as Treatment for Graves Disease. Clin Med Insights Endocrinol Diabetes 12:1179551419844523
Anuwong A, Sasanakietkul T, Jitpratoom P, Ketwong K, Kim HY, Dionigi G, Richmon JD (2018) Transoral endoscopic thyroidectomy vestibular approach (TOETVA): indications, techniques and results. Surg Endosc 32(1):456–465
Liu ZW, Masterson L, Fish B, Jani P, Chatterjee K (2015) Thyroid surgery for Graves’ disease and Graves’ ophthalmopathy. Cochrane Database of Systematic Reviews 2015(11)
Yang YT, Chen JF, Tung SC, Kuo MC, Weng SW, Chou CK, Shen FC, Chang CM, Tsai CJ, Taso CF et al (2020) Long-term outcome and prognostic factors of single-dose Radioiodine Therapy in patients with Graves' disease. J Formos Med Assoc 119(5):925–932
Brunn J, Block U, Ruf G, Bos I, Kunze WP, Scriba PC (1981) [Volumetric analysis of thyroid lobes by real-time ultrasound (author's transl)]. Dtsch Med Wochenschr 106(41):1338–1340
Wu Y-J, Chang Y-H, Tsai C, Chan Y-C, Chi S-Y, Chou F-F, Lin W-C, Yang YT (2023) Combination of treatments with transoral endoscopic thyroidectomy vestibular approach (TOETVA) for Graves’ disease. Sci Rep 13(1)
Léger J, Carel JC (2013) Hyperthyroidism in childhood: causes, when and how to treat. J Clin Res Pediatr Endocrinol 5(Suppl 1Suppl 1):50–56
Achonu CU, Olopade OB, Yusuf BO, Fadeyi AA, Fasanmade OA (2023) Case Report of Graves' Disease in a 45-Year-Old Woman Secondary to Herceptin Treatment for Breast Cancer. 42(6):194–202
Sánchez-Bayona R, Garcia del Barrio MA, Alegre E, Fernandez-Hidalgo OA, Eslava MS (2022) Trastuzumab and thyroid dysfunction: An association to be aware of. 18(4):1183–1185
Min HK, Kim IH, Kim JY, Ban TH, Kim KH, Ha J, Kim JH (2016) Trastuzumab-associated autoimmune thyroid disease in a patient with metastatic breast cancer. Korean J Intern Med 31(3):608–611
Jitpratoom P, Ketwong K, Sasanakietkul T, Anuwong A (2016) Transoral endoscopic thyroidectomy vestibular approach (TOETVA) for Graves' disease: a comparison of surgical results with open thyroidectomy. Gland Surg 5(6):546–552
Yamanouchi K, Minami S, Hayashida N, Sakimura C, Kuroki T, Eguchi S Predictive factors for intraoperative excessive bleeding in Graves' disease. (0219–3108 (Electronic)).
Zhao W, Gao BL, Yang HY, Li H, Song DP, Xiang ST, Shen J (2007) Thyroid Arterial Embolization to Treat Graves' Disease. Acta Radiol 48(2):186–192
Xiao H, Zhuang W, Wang S, Yu B, Chen G, Zhou M, Wong NCW (2002) Arterial Embolization: A Novel Approach to Thyroid Ablative Therapy for Graves’ Disease. J Clin Endocrinol Metabolism 87(8):3583–3589
Stalberg P, Svensson A, Hessman O, Akerstrom G, Hellman P (2008) Surgical treatment of Graves' disease: evidence-based approach. World J Surg 32(7):1269–1277
Cai G, Luo B, Wang M, Su J, Lin L, Li G, Chen X, Huang Z, Lin P, Liu S et al (2024) Efficacy and safety of ultrasound-guided thermal ablation of graves' disease: a retrospective cohort study. Thyroid Res 17(1):10
Schneider AB, Gierlowski TC, Shore-Freedman E, Stovall M, Ron E, Lubin J (1995) Dose-response relationships for radiation-induced hyperparathyroidism. J Clin Endocrinol Metab 80(1):254–257
Metso S, Jaatinen P, Huhtala H, Auvinen A, Oksala H, Salmi J (2007) Increased cardiovascular and cancer mortality after radioiodine treatment for hyperthyroidism. J Clin Endocrinol Metab 92(6):2190–2196
Leso V, Vetrani I, De Cicco L, Cardelia A, Fontana L, Buonocore G, Iavicoli I (2020) The Impact of Thyroid Diseases on the Working Life of Patients: A Systematic Review. Int J Environ Res Public Health 17(12)
Lee JA, Grumbach MM, Clark OH (2007) The optimal treatment for pediatric Graves' disease is surgery. J Clin Endocrinol Metab 92(3):801–803
Choi Y, Lee JH, Kim YH, Lee YS, Chang HS, Park CS, Roh MR (2014) Impact of postthyroidectomy scar on the quality of life of thyroid cancer patients. Ann Dermatol 26(6):693–699
Statements & Declarations

Table 1: Patient Demographics and Preoperative Characteristics

Variables	TT=11	ST=7	Dh=15	p
Sex (F/M)	11/0	7/0	14/1	1.000
Age (years), mean ± SD	35.18±9.06, (34)	31.14±9.87, (28)	24.8±6.64, (24)	*TT>Dh, 0.003
Goiter grade, n (%)				0.597
0	1 (9.1%)	0 (0%)	0 (0%)
1	1 (9.1%)	0 (0%)	1 (6.7%)
2	7 (63.6%)	4 (57.1%)	12 (80%)
3	2 (18.2%)	3 (42.9%)	2 (13.3%)
ATD (months), mean ± SD	19.36±10.7, (18)	32±17.38, (30)	15.93±6.23, (15)	*ST>Dh, 0.01

Abbreviations: ATD, antithyroid drugs

Table 2: Operative and Immediate Postoperative Outcomes

Variables	TT=11	ST=7	Dh=15	p
SETA, n (%)	9 (81.8%)	5 (71.4%)	15 (100%)	0.088
RFA, n (%)	0 (0%)	7 (100%)	1 (6.7%)	*<0.001
Resection weight, gm	57.69±22.25	36.79±4.62	72.94±23.90	*0.001
IOBL (ml), median (range)	5 (1-10)	80 (10-800)	10 (5-250)	*<0.001
Drainage placement, n (%)	0 (%)	3 (42.9%)	1 (6.7%)	*0.006
Hospital stay (days), mean ± SD	3.45 ± 0.93	5.57 ± 1.4	2.87 ± 0.64	*<0.001

Abbreviations: SETA, selective embolization of the thyroid artery; RFA, radiofrequency ablation; IOBL, intraoperative blood loss

Table 3: Postoperative Long-term Outcomes and Complications

Variables	TT=11	ST=7	Dh=15	p
Temporary hypoparathyroidism, n	3	0	0	*0.037
Permanent hypoparathyroidism, n	0	0	0	1.000
Recurrent laryngeal nerve injury, n	0	0	0	1.000
Euthyroidism at 6 months, n	0	3	2	0.565
Hypothyroidism at 6 months, n	11	0	13	*<0.001
Recurrent hyperthyroidism, n	0	4	0	*0.006
Remanent volume	--
left	--	2.42±0.55	2.61±0.31	0.355
right	--	2.58±1.28	2.13±0.20	0.848
Total=left + right	--	4.99±1.74	2.39±0.36	*<0.001

The authors declare no competing interests.

Customized Treatment of Graves' Disease by Transoral Endoscopic Thyroidectomy Vestibular Approach: A Retrospective Cohort Study with Long-term Follow-up

Status:

Version 1

Abstract

Purpose

Methods

Results

Conclusion

Introduction

Materials and Methods

Study Design and Patient Selection

Surgical Techniques

Data Collection and Follow-up

Statistical Analysis

Results

Patient Demographics

Procedure Distribution

Postoperative Long-term Results

Discussion

Efficacy and Recurrence

Surgical Complications

Surgery first after ATD control of thyroid function

Customized Approach

Limitations and Future

Conclusion

Declarations

References

Tables

Additional Declarations

Status:

Version 1