Efficacy of transoral vestibular endoscopic thyroidectomy versus open surgery in the treatment of unilateral thyroid malignancies

Introduction

Thyroid cancer, a malignancy in the head and neck region, is the most common malignancy of the endocrine (hormonal) system, and its prevalence rate in women is significantly higher than in men (1), which has a great impact on the normal life, work, and psychology of patients (2). Surgical resection is the first choice of treatment for patients with thyroid malignancies. The traditional open thyroidectomy often leaves an unsightly surgical scar on the anterior neck of the patient after surgery. This is not conducive to the postoperative mental health and recovery of female patients who are concerned with the cosmetic effects (3). With continuous advancements in medical technology, endoscopic surgery involves surgeons conducting operations by images transmitted to a monitor, using specialized surgical instruments inserted through small incisions. This method is minimally invasive and can perfectly solve patient’ needs for cosmetic concerns. Currently, surgical approaches for thyroid tumors mainly include Miccoli, subclavian, breast-chest, and oral vestibular approaches (4-9). The oral and complete areolar approaches are primary methods for endoscopic surgery, while the axillary approach has emerged as a novel technique. Each approach has its own set of advantages and disadvantages. Therefore, in clinical practice, it is essential to carefully evaluate the patient’s condition to determine the most appropriate approach for each individual. The primary goal of any surgical approach for thyroid malignancy remains complete oncologic resection. Endoscopic techniques aim to achieve this fundamental objective while minimizing surgical trauma and improving cosmetic outcomes.

In order to evaluate the safety and efficacy of endoscopic surgery for unilateral thyroid malignancies, we conducted a retrospective analysis of the clinical records for 105 patients diagnosed with unilateral thyroid cancers who underwent surgical intervention at our institution between January 2021 and June 2024. We compared the perioperative and postoperative conditions, including serological indicators, postoperative complications, and satisfaction of patients undergoing endoscopic surgery and open surgery and aim to provide a reference for clinical selection of appropriate surgical methods. We present this article in accordance with the STROBE reporting checklist (available at https://gs.amegroups.com/article/view/10.21037/gs-2025-448/rc).

Methods

General data

A total of 184 patients with unilateral thyroid malignant tumors who underwent surgical treatment between January 2021 and June 2024 were retrospectively included in this study. Patients in the open surgery group were consecutively collected from The Second People’s Hospital of Liangshan Yi Autonomous Prefecture, while patients in the endoscopic surgery group were collected during the same study period from the First People’s Hospital of Lanzhou City. Patients were classified into an endoscopic surgery group (n=58) and an open surgery group (n=126) according to the surgical approach. To minimize selection bias, propensity score matching (PSM) was performed at a ratio of 1:2. The matching variables included sex, age, disease duration, body mass index, tumor location, and maximum tumor diameter. After matching, 35 patients were assigned to the endoscopic surgery group and 70 patients to the open surgery group, as shown in Figure 1. Inclusion criteria were as followed: (I) intraoperative and postoperative pathological diagnosis of thyroid malignant tumors; (II) age 20–75 years old; (III) tumors located unilaterally. Exclusion criteria were as followed: (I) patients with severe cardiovascular and cerebrovascular diseases; (II) previous history of head and neck surgery; (III) severe coagulation abnormalities; (IV) pregnant and lactating women; (V) patients with aesthetic requirements; (VI) patients requiring extensive cervical lymph node dissection (palpable lymph nodes). This study protocol was reviewed and approved by Ethics Committee of The Second People’s Hospital of Liangshan Yi Autonomous Prefecture (approval No. 202302001). The other participating hospital was also informed of and agreed to this study. Since this study is a retrospective cohort study and the identification information of patients has anonymity, there is no need for informed consent from patients and their families. The study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments.

Figure 1 Study flowchart of patient inclusion. PSM, propensity score matching; TOETVA, transoral vestibular endoscopic thyroidectomy.

Rationale for surgical procedure selection

This being a retrospective cohort study, the choice between transoral vestibular endoscopic thyroidectomy (TOETVA) and conventional open surgery was made through a shared decision-making process between the surgeon and the patient, based on comprehensive clinical assessment and patient preferences. The general considerations included:

Tumor characteristics: TOETVA was primarily offered to patients with preoperatively assessed unilateral tumors of limited size (typically maximal diameter ≤4 cm) and without evidence of extensive extrathyroidal extension (ETE) or significant central/lateral lymph node metastasis on ultrasound.

Patient factors: patient desire for a scarless neck was a strong motivating factor for considering TOETVA. Conversely, patients with a history of oral or neck infections, severe dental disease, limited mouth opening, or significant concerns about the novel endoscopic approach were more likely to undergo open surgery.

Surgeon experience & institutional protocol: the endoscopic procedures were performed by surgeons who had completed the learning curve for TOETVA. During the early phase of implementing this technique, patient selection was more conservative.

Ultimately, the final decision was individualized. The PSM performed subsequently aimed to minimize the confounding effects of these baseline clinical variables when comparing outcomes between the two cohorts.

Surgery method

The management of patients in this study adhered to internationally accepted clinical guidelines and consensus statements to ensure standardized and evidence-based care. Preoperative evaluation and surgical planning were guided by the American Joint Committee on Cancer (AJCC) Tumor-Node-Metastasis (TNM) Staging System (8th Edition) (10) for differentiated thyroid cancer. The decision for surgical intervention and the extent of resection (lobectomy vs. total thyroidectomy, central compartment dissection) were made in accordance with the recommendations of the American Thyroid Association (ATA) Management Guidelines for Adult Patients with Thyroid Nodules and Differentiated Thyroid Cancer (11).

All surgical procedures in this study were performed by a dedicated endocrine surgery team to minimize operator-dependent variability. The team consisted of two attending surgeons, each with over 10 years of experience in conventional open thyroidectomy and more than 5 years of experience in endoscopic thyroid surgery. Both surgeons had completed structured training in TOETVA, including cadaveric workshops and proctored cases. Prior to the commencement of this study period, each surgeon had independently performed more than 30 TOETVA procedures, a volume considered sufficient to surpass the initial learning curve for this technique as suggested in the literature. All endoscopic procedures in this cohort were performed under the direct supervision or as the primary operator by one of these two surgeons. To ensure consistency, the surgical steps for both TOETVA and open surgery were performed according to a standardized institutional protocol, as detailed in the ‘Surgery method’ section. This protocol was established based on accepted international guidelines and consensus statements.

All patients undergoing endoscopic surgery received total lobectomy on the affected side + isthmectomy + central lymph node dissection approach. A chlorhexidine gargle was used 3 days before surgery, and 1.5 g of Encoloxin was prophylactically used 0.5 h before surgery. Under general anesthesia, a soft pillow was placed under the patient’s shoulder to maintain the hyperextension position. After disinfection, the oral cavity was disinfected using a mixture of painless iodine and normal saline (1:2). The intraoperative procedures of endoscopic surgery were shown in Figure 2. During surgery, the lower lip was pulled open to expose the labial buccal and gingival sulci. A 10 mm incision was made at the upper end of the lower lip frenum. An electric knife was used to separate it from the mandibular periosteum into the submental space. The soft tissue was expanded with a stripping rod to establish a cavity, and a 10 mm trocar was placed as an observation hole. Make a 5 mm incision at the upper end of the left and right first bicuspids, and place a 5 mm trocar on each as the operating hole. The holes were filled with carbon dioxide gas to maintain a pressure of approximately 8 mmHg. The flap was dissected using an ultrasonic scalpel in the subplatysmal space, down to the sternum, and bilaterally to the anterior border of the claviculomastoid muscle. Open the linea alba and place an endoscopic surgery “S” retractor to retract strap muscles. The central approach was used to perform a total lobectomy on the affected side + isthmectomy + central lymph node dissection on the affected side, with intraoperative frozen section for pathological examination, followed by dissection of the central lymph node region. The recurrent laryngeal nerve (RLN) was meticulously identified and dissected along its course under endoscopic magnification, with careful preservation of its integrity. Surgery should be performed close to the gland to prevent damage to the superior laryngeal nerve. Superior and inferior parathyroid glands were identified, and efforts were made to preserve them in situ with their vascular supply intact. If devascularization occurred or a parathyroid gland was inadvertently removed, it was immediately autotransplanted into the sternocleidomastoid muscle. The wound was irrigated with distilled water, a drain was placed in the central area, the cavity and oral incision were closed using absorbable sutures, and the mouth was disinfected. Prophylactic intravenous antibiotics (cefazolin 1 g every 8 hours or an equivalent alternative in case of penicillin allergy) were administered for 24 hours postoperatively. A compression bandage using elastic bandages was applied to the submental and anterior cervical region immediately after surgery and maintained for 3–5 days to minimize swelling and potential dead space.

Figure 2 Intraoperative picture of patients undergoing endoscopic surgery. (A) Lacunae were established lateral to the lateral margins of the bilateral sternocleidomastoid muscles, extending inferiorly to the sternal stalk. (B) The neck white line was incised to access the surgical field. (C) The anterior laryngeal lymph nodes were dissected and cleared. (D) The isthmic portion of the thyroid gland was resected at the level of the right thyroid lobe. (E) The superior blood vessels of the left thyroid lobe were ligated and divided. (F) The superior portion of the left thyroid lobe was excised. (G) The left upper parathyroid gland was identified, exposed, and carefully dissected. (H) Under laparoscopic guidance, the left recurrent laryngeal nerve was identified. (I,J) The recurrent laryngeal nerve was fully visualized, and the thyroid gland was dissected under laparoscopic guidance, followed by clearance of the central lymph nodes. (K) The left recurrent laryngeal nerve was preserved throughout the procedure, and the thyroid gland was completely resected with central lymph node dissection. (L) The left thyroid lobe and central lymph nodes were retrieved using a specimen bag. (M) Hemostasis was achieved, a drainage tube was placed, and the white line and intraoral incision were closed with sutures.

Patients in the open surgery group received conventional open surgery via an anterior cervical incision. The patients were placed in the supine position with cervical hyperextension and general anesthesia with endotracheal intubation. A 5 cm arc incision was made at 2 transverse fingers above the patient’s sternal manubrium. The skin and subcutaneous tissue were incised, the skin flap was freed, the linea alba and anterior cervical muscle groups were opened, and the isthmus and bilateral thyroid glands were exposed. Thyroid tumor removal, partial thyroidectomy, subtotal thyroidectomy, or total thyroidectomy performed based on the results of intraoperative exploration including the size, number, and location of the tumor. RLN was routinely identified and protected. Parathyroid glands were identified and preserved in situ or autotransplanted if necessary. Central compartment lymph node dissection was performed according to standard boundaries. The RLN was exposed and properly protected throughout the course, and the thyroid tissue was removed from the dorsal capsule to protect the parathyroid glands. Routine intraoperative pathological examination was performed, and lymph nodes in the central area were dissected after being submitted for examination. After hemostasis of the wound surface, a negative pressure drainage tube was placed, sutured layer-by-layer, and the incision was compressed and bandaged. Similar to the endoscopic group, prophylactic intravenous antibiotics (cefazolin 1 g every 8 hours) were given for 24 hours. A sterile dressing was applied to the cervical incision, followed by a light pressure dressing over the anterior neck to support the wound and reduce edema, which was typically removed or replaced on postoperative day 1 or 2. The intraoperative procedures of open surgery were shown in Figure 3.

Figure 3 Intraoperative photograph illustrating anatomical exposure during open thyroid surgery. This image demonstrates the surgical field after midline incision and strap muscle retraction, showing key anatomical structures relevant to thyroidectomy, including bilateral recurrent laryngeal nerves and parathyroid glands. The procedure performed in this specific case was a right lobectomy and isthmectomy with central lymph node dissection. The wide exposure is for illustrative purposes to highlight nerve and gland preservation techniques. This figure is selected to clearly demonstrate the critical anatomical structures (recurrent laryngeal nerves and parathyroid glands) that are routinely identified and preserved during open thyroid surgery, regardless of the laterality of the resection. Figure 2: intraoperative picture of patients undergoing open surgery for right lobe and isthmus resection + right recurrent laryngeal nerve exploration + right central lymph node dissection. a, right common carotid artery; b, right recurrent laryngeal nerve; c, right lower parathyroid gland; d, right upper parathyroid gland; e, trachea; f, trachea; g, left recurrent laryngeal nerve; h, left upper parathyroid gland; i, left lower parathyroid gland.

Observation indicators

Surgical-related parameters were meticulously documented for both cohorts, including surgical duration, intraoperative blood loss, volume of postoperative drainage, length of postoperative hospitalization, neck pain score, scar features, cosmetic satisfaction, and post-operative complications. The measurement of serum biomarkers were performed 24 hours post-surgery including C-reactive protein (CRP), tumor necrosis factor-α (TNF-α), and parathyroid hormone (PTH) levels. The surgical time was recorded from the start of the skin incision to the final suture placement. Intraoperative bleeding was assessed by summing the volume of aspirated blood. Postoperative drainage volume was defined as the total output collected from the wound drainage tube before its removal.

Neck pain levels were assessed using the visual analogue scale (VAS) at 24 hours postoperatively for all patients, with a maximum score of 10 indicating severe pain. Scar features at the cervical incision site were assessed using the Vancouver Scar Scale (VSS), a validated tool for evaluating cutaneous scars based on parameters such as color, vascularity, thickness, and pliability, with a lower score indicating a more favorable appearance. For patients in the endoscopic surgery group (transoral vestibular approach), the VSS was not applied to the intraoral mucosal incision, as this scale is not validated for mucosal healing. Instead, in this group, the VSS served as a reference tool to evaluate any potential visible sequelae in the submental/neck region related to the surgical dissection tunnel, allowing for a comparative assessment of the overall aesthetic impact between the two surgical approaches.

Additionally, through consultations and telephone follow-ups cosmetic satisfaction post-surgery was collected using a modified 10-point grading system, where a perfect score of 10 reflected high satisfaction levels. Scores were assigned as follows: 1–2 point for very dissatisfied, 3–4 points for dissatisfied, 5–6 points for generally satisfied, 7–8 points for satisfied, and 9–10 points for very satisfied. Long-term postoperative complications were monitored over a 6-month follow-up period to comprehensively assess patient outcomes, including dysphagia, hoarseness, paresthesia, subcutaneous fluid accumulation, and infection. At the same time, the recurrence rate of both groups of patients was counted at 6 months after surgery.

Definition and grading of postoperative complications

Postoperative complications were systematically recorded during the hospital stay and throughout the 6-month follow-up period. A complication was defined as any adverse event occurring within 30 days after surgery that was deemed related to the surgical procedure. Specifically, we monitored for: hoarseness (subjective voice change or objective vocal cord palsy on laryngoscopy), choking (difficulty swallowing liquids, suggestive of possible RLN dysfunction), transient hypoparathyroidism (symptomatic hypocalcemia or PTH level <15 pg/mL requiring supplementation), hematoma/bleeding requiring intervention, surgical site infection (requiring antibiotic treatment or drainage), seroma/subcutaneous effusion requiring aspiration, and transient neurological symptoms.

Pathologic and oncologic assessment

All surgical specimens were subjected to intraoperative frozen section examination and subsequent definitive histopathological analysis. Margins were assessed according to the presence of tumor cells at the inked resection margin, classified as R0 (negative margin) or R1 (positive margin). The number of lymph nodes retrieved from the central compartment was recorded for each patient. Microscopic ETE was defined as tumor extension beyond the thyroid capsule identified on histology. These parameters were compared between the two groups to evaluate short‑term oncologic adequacy.

Statistical analysis

SPSS 26.0 software was used to analyze the data, and the nearest neighbor matching method was used to carry out 1:2 matching, and the caliper value was 0.03. The matching variables were selected based on their known clinical relevance to surgical outcomes and included: sex, age, disease course, body mass index, lesion location, and maximum tumor diameter. Variables such as detailed tumor histopathological subtypes (e.g., classic papillary vs. follicular variant) and specific molecular markers were not included in the PSM model due to inconsistent availability in the retrospective records for the entire cohort, but they are reported and compared between the matched groups in the results. The success of matching was assessed by comparing standardized mean differences (SMDs), with an SMD <0.1 indicating good balance. All measurement data have been tested for normal distribution by S-W test. Measurement data that conform to normal distribution are represented by (x¯±S) and analyzed by t-test, while measurement data with skewed distribution are represented by median [interquartile range (IQR)] and were analyzed using the U test. The counting data were described by use case (%), and the comparison between the two groups was performed by χ² test. The difference was statistically significant with P<0.05.

Results

Comparison of baseline data before and after PSM between the two groups

Patients were stratified into two cohorts based on the surgical approach employed: the endoscopic surgery group (n=58) and the open surgery group (n=126). Significant variations were observed in age and maximum tumor diameter (P<0.05), as outlined in Table 1. To mitigate these variances and align both groups on a comparable baseline, SPSS 26.0 software and PSM methodology were utilized at a 1:2 ratio. The matching criteria including gender, age, disease duration, body mass index, lesion site, and maximum tumor diameter. Subsequently, 35 patients were selected in the endoscopic surgery group and 70 patients were selected in the open surgery group following PSM. After matching, no notable differences in baseline characteristics were evident (P>0.05), as detailed in Table 2.

Comparison of detailed histopathological characteristics between the two groups after PSM

After PSM, the two groups were well-balanced in terms of the measured demographic and clinical covariates (Table 2). Furthermore, as presented in Table 3, there were no statistically significant differences in key detailed histopathological features, including tumor subtype distribution, multifocality, rate of ETE, and presence of central lymph node metastasis between the matched cohorts, as detailed in Table 3.

Comparison of perioperative indexes between the two groups

Patients in the endoscopic surgery group had significantly longer surgical times and shorter length of postoperative hospital than those in the open surgery group (P<0.05). The intraoperative blood loss and the volume of postoperative drainage of the patients in the endoscopic surgery group were significantly lower than those in the open surgery group (P<0.05), as shown in Table 4.

Comparison of serum indexes between the two groups

After surgery, the serum levels of CRP and TNF-α in endoscopic surgery group were significantly lower than those in open surgery group (P<0.05), but there was no significant difference in serum PTH level between two groups (P>0.05), as shown in Table 5.

Comparison of scores of neck pain and scar features, and cosmetic satisfaction between the two groups after surgery

After surgery, the neck pian scores and Scar features scores for patients in the endoscopic surgery group were lower than those in the open surgery group (P<0.05), and the cosmetic satisfaction scores in the endoscopic surgery group was higher than that in the open surgery group (P<0.05), as shown in Table 6.

Comparison of postoperative complications between the two groups after surgery

The data revealed a noteworthy disparity in the occurrence of overall complications between the two groups, with the endoscopic surgery cohort exhibiting a notably lower incidence (11.6%) than that of the open surgery group (40.0%). This discrepancy underscored the statistically significant difference in complication rates between the two cohorts (P<0.05), as evidenced in Table 7.

Comparison of pathologic and oncologic outcomes between the two groups

Pathologic examination confirmed that all patients underwent complete resection of the primary tumor. As shown in Table 7, there were no significant differences between the endoscopic and open surgery groups in terms of R0 resection rate (94.3% vs. 92.9%, P=0.77), median number of central lymph nodes retrieved [4 (IQR, 2–6) vs. 5 (IQR, 3–7), P=0.12], or incidence of microscopic ETE (11.4% vs. 14.3%, P=0.65). These findings suggest that endoscopic surgery achieved comparable oncologic resection quality to open surgery in the studied cohort, as evidenced in Table 8.

Comparison of recurrence rate between the two groups

The recurrence rate of the endoscopic surgery group was 8.57% (3/35), while the recurrence rate of the open surgery group was 7.14% (5/70). There was no statistically significant difference in recurrence rates between the two groups of patients (P<0.05).

Discussion

The relentless human pursuit of aesthetic perfection has driven surgeons to continually refine surgical techniques. A landmark development occurred in 1997 when Hüscher et al. introduced the first endoscopic surgery for thyroidectomy (12). After more than two decades of development, endoscopic surgery has become widely used in clinical practice (13-15). As early as 2018, the Thyroid Surgery Committee of the Surgical Branch of the Chinese Medical Association issued an expert consensus on endoscopic thyroid surgery through the oral vestibular approach. Since then, with the continuous development of surgery, the treatment of thyroid malignant tumors through the oral vestibular approach has become a very common surgical method in clinical practice. Endoscopic surgery aims to relocate the visible neck incision to a less conspicuous part of the body, utilizing a minimal access point to introduce ultrasonic scalpels and other instruments via a subcutaneous tunnel, with the operation being conducted under laparoscopic guidance (16). Currently, many surgical approaches are available for the treatment of thyroid tumors. Because of the short distance from the oral cavity to the affected site and the fact that scarring does not occur after healing of the oral mucosa, the transoral vestibular approach is more commonly used (17). Guo et al. (18) reported no significant differences in bleeding, surgery time, total postoperative drainage volume, drainage time, duration of postoperative pain, recovery time, postoperative length of stay, and incidence of postoperative adverse reactions between the breast approach and oral vestibular approach in the treatment of thyroid tumors. However, patients were generally more satisfied with the cosmetic effect of the oral vestibular approach than that the breast approach. Moreover, the oral vestibular approach is more conducive to postoperative self-confidence, rapid recovery, and improvement of quality of life due to its better cosmetic effect (19). Zhou et al. conducted a questionnaire survey among 40 patients opting for the oral vestibular approach for thyroid tumor resection. Multivariate analysis indicated a significant positive correlation between the choice of this approach and factors such as the patient’s age, perceived cosmetic outcomes, safety, minimally invasive nature of the treatment, and medical advice. Conversely, variables such as educational level, health insurance coverage, family support, previous surgical history, and surgery-related symptoms showed no correlation with the choice of surgical approach (20). Karakas et al. observed a transient postoperative increase in white blood cell count following the oral vestibular approach, which, however, did not correlate with significant wound infections (21). Postoperative intravenous antibiotics can be used as prophylaxis to avoid microbial partitioning from the mouth into the thyroid region.

The findings of this study indicated that the duration of surgery was significantly longer for the endoscopic surgery group compared to the open surgery group. This extended duration was attributable to several factors: assembling the endoscopic system, transitioning and adapting various surgical instruments such as the electric knife and hook, and establishing the surgical cavity, which collectively prolonged the endoscopic procedure (22). However, with the improvement of the medical staff’s proficiency in instrument surgery and team cooperation, the time for surgery will be gradually shortened. In terms of postoperative drainage volume, the endoscopic group exhibited less tissue damage, resulting in diminished tissue edema and exudation, thereby reducing the volume of drainage. Conversely, open surgery, which inflicts more substantial damage to muscles and other tissues, leads to greater drainage volume. Consequently, patients undergoing open surgery require more extended periods awaiting the removal of the drainage tube, which in turn prolongs their hospitalization. In terms of bleeding volume, enlargement of the endoscopic surgical field facilitates fine management of blood vessels, while the endoscopic surgery approach does not cut off the platysma muscle and thus avoids hemorrhage of intermuscular vessels.

Importantly, our pathologic analysis demonstrated that endoscopic surgery achieved R0 resection rates, central lymph node yields, and rates of microscopic ETE that were comparable to those of open surgery. These short-term oncologic indicators support the premise that the transoral vestibular approach does not compromise the completeness of tumor resection when performed in appropriately selected patients. Nevertheless, long-term recurrence and survival data remain essential to fully establish oncologic equivalence.

CRP and TNF-α are common inflammatory markers in clinical practice, and their elevation indicates that the body undergoes an inflammatory response. The findings of this study showed that the VAS scores, serum CRP and TNF-α levels 24 h after surgery in the endoscopic surgery group were significantly lower than those in the open surgery group, suggesting that endoscopic surgery is helpful in relieving postoperative pain and reducing inflammatory reactions. This could be attributed to the technique of endoscopic surgery, which involves creating a lumen beneath the platysma surface without incising the muscle. Furthermore, the routine administration of antibiotics post-surgery contributes to milder postoperative pain and inflammation, enhancing patient comfort (23). Additionally, the study found no significant differences in PTH levels between the two groups post-surgery. This lack of disparity may stem from the ability of endoscopic surgery to preserve the tissue around the thyroid gland, including the parathyroid gland, thereby minimizing the risk of glandular damage. During open surgery, attention should be paid to avoid damage to the parathyroid gland. Therefore, there is no significant difference in the effect of the two procedures on the parathyroid gland.

The overall complication rate observed in the open surgery group (40.0%) is higher than some benchmarks in the literature. This is likely attributable to our study’s inclusive definition of complications, which captured all documented postoperative symptoms, however minor or transient, through meticulous retrospective chart review. Many of these events (e.g., subjective hoarseness lasting a few days) might not be systematically recorded or reported in studies employing a stricter definition. In contrast, when assessed by the Clavien-Dindo classification, the rate of clinically significant complications (Grade II and above) in the open surgery group was 14.3%, which aligns more closely with expected ranges for conventional thyroidectomy. This underscores the importance of standardized grading when comparing surgical outcomes. The significantly lower rate of both overall and clinically relevant complications in the endoscopic group remains a robust finding supporting its safety profile.

At present, the mainstream endoscopic surgery for thyroid surgery is the external cervical approach, and its postoperative satisfaction with neck appearance must be higher than that of the traditional open surgery. Consequently, comparing satisfaction with neck appearance between these two patient groups may offer limited insight. Although the total areola and axillary approaches still result in scars on the body surface, the transoral vestibular approach involves isolating the operational space in the anterior cervical region without leaving any surface scars or affecting oral function, which enhances patient acceptance (24). Although the transoral vestibular approach to endoscopic thyroidectomy currently has certain advantages, it also has some limitations. This surgical approach is mainly suitable for smaller thyroid malignancies. For larger tumors or certain special types of tumors, such as medullary thyroid carcinoma, this surgical method may not be able to completely resect the tumor tissue, or the difficulty of the surgery may increase significantly. In addition, for middle and late-stage thyroid malignancies that have already metastasized to lymph nodes or other parts, a simple transoral vestibular approach to endoscopic thyroidectomy is often insufficient to achieve a radical cure. It needs to be combined with other treatment methods, such as lymph node dissection, radiotherapy, chemotherapy, etc. Therefore, in this study, patients were fully evaluated before surgery, and if extensive lymph node metastasis was found during surgery or the situation was inconsistent with the preoperative assessment, timely communication with the patients’ families will be conducted. After obtaining the consent of the family members, the health of the patients will still be given priority consideration and the operation will be converted to an open surgery.

In this study, we found that the incidence of postoperative complications, such as choking, hoarseness, limb numbness, subcutaneous effusion, and infection in the observation group, was significantly lower in the endoscopic surgery group than in the open surgery group. Despite the surgical incision in the oral vestibular approach transitioning from type I to type II, potentially elevating the risk of surgical infection, the routine administration of antibiotics post-surgery mitigates this risk. Consequently, endoscopic surgery does not inherently increase the risk of infection. In this study, only one patient in the endoscopic surgery group had mandibular numbness, which was related to stretching of the mental nerve during surgery. However, few patients in the open surgery group had symptoms of limb numbness, which may be related to the influence on the brachial plexus during surgery. Hoarseness and choking when drinking water may be caused by excessive traction of the RLN during surgery. However, follow-up investigations conducted over six months revealed that most symptoms resolved spontaneously.

Consideration of surgical trauma mechanisms

The reviewer raises a pertinent point regarding the potential inflammatory stimulus from tissue tunneling during endoscopic space creation. We agree that this represents a form of mechanical stress. However, the observed lower inflammatory markers (CRP, TNF-α) and pain scores in the endoscopic group suggest that the nature and distribution of surgical trauma differ fundamentally between approaches. In conventional open surgery, despite a single skin incision, access to the thyroid gland requires sustained retraction, dissection, and often partial division of the platysma, sternohyoid, and sternothyroid muscles. This concentrated mechanical trauma to functionally active muscle and fascial planes likely triggers a significant local and systemic inflammatory response. In contrast, the transoral endoscopic approach creates its working space primarily in the relatively avascular subplatysmal plane using blunt dissection and hydraulic expansion with CO₂ insufflation. While this involves a broader subcutaneous dissection, it meticulously avoids transection of the major cervical muscles. The trauma is thereby “distributed” over a larger area but to anatomically less reactive, inert fatty and loose connective tissue. Furthermore, the magnified endoscopic view permits finer dissection and more precise hemostasis, potentially reducing occult tissue injury and hematoma formation, which are potent triggers of inflammation. Thus, the net biologic insult—and consequent inflammatory cascade—appears to be less in the endoscopic approach, as reflected in our biochemical and clinical findings.

Currently, numerous comparative studies examine endoscopic and open surgeries for treating thyroid malignancies. However, the reliability of these studies is often compromised by confounding factors that influence clinical outcomes. To address this issue, PSM was employed in this study to compare the efficacy and safety of endoscopic surgery versus open surgery. There were statistically significant differences in age and maximum tumor diameter between the two groups before PSM, and the baseline data of the two groups after PSM were basically balanced, avoiding the influence of confounding factors on the results. At the same time, there are also shortcomings in the research. The most significant limitation of this study is the relatively short follow-up period (data collection concluded in June 2024). This duration is insufficient to draw definitive conclusions regarding long-term oncologic outcomes such as disease recurrence or survival.

A key strength of this study is the application of PSM to balance observed baseline confounders, strengthening the comparability of our cohorts over a simple retrospective comparison. However, consistent with the reviewer’s insightful comment, it is crucial to acknowledge that PSM can only account for measured and included covariates. Residual confounding from unmeasured or unrecorded factors, such as subtle differences in genetic tumor profiles, microscopic vascular invasion, or surgeon’s technical nuances beyond case volume, may persist.

In particular, while our post-matching analysis showed no significant differences in major histopathological features (Table 3), the retrospective design limited our ability to uniformly incorporate highly granular pathological data (e.g., comprehensive molecular profiling) into the formal matching model. Therefore, our results provide strong associative evidence that the transoral endoscopic approach, when applied to patients with similar baseline and pathological profiles, is associated with superior perioperative outcomes. They should be interpreted as demonstrating comparative effectiveness in a real-world clinical setting rather than definitive causal proof. Future prospective studies with protocol-mandated, comprehensive pathological and molecular workup are needed to fully adjust for these biological confounders and solidify causal inferences.

This study has several limitations that should be considered when interpreting the results. First, the retrospective, non-randomized design carries an inherent risk of selection and information bias. Although we employed PSM to balance key baseline variables, unmeasured confounding factors may persist. Second, the follow-up period (data collection concluded in June 2024) is relatively short for an oncologic study. While we have reported promising short-term pathologic and safety outcomes, this duration is insufficient to draw definitive conclusions regarding long-term oncologic endpoints such as disease recurrence and survival. Third, there are limitations in the assessment of certain outcomes. The evaluation of RLN function relied primarily on clinical symptoms rather than routine postoperative laryngoscopy for all patients. Additionally, the VSS, used for cosmetic comparison, is validated for cutaneous scars and was applied here as a reference tool rather than a direct measure of mucosal healing in the endoscopic group. Finally, as a single-center study with strict inclusion criteria (e.g., tumor size, no extensive metastasis for the endoscopic approach), the generalizability of our findings to broader patient populations or different surgical settings may be limited. Future prospective, multi-center studies with longer follow-up and standardized outcome assessments are warranted to validate and extend our conclusions. At the same time, the assessment of RLN function in this retrospective study relied primarily on the documentation of clinical symptoms rather than on systematic, protocol-mandated postoperative laryngoscopy for all patients. While laryngoscopy was utilized in cases of symptomatic presentation, the lack of uniform objective assessment for all patients is a limitation that may affect the precision of nerve injury rates. Future prospective studies should incorporate routine pre- and postoperative laryngoscopy to provide more definitive data on vocal cord function. Future studies with extended follow-up are crucial to validate the oncologic safety of the endoscopic approach compared to open surgery.

Conclusions

In conclusion, when performed with strict adherence to oncologic principles (total lobectomy + isthmusectomy + central neck dissection) in appropriately selected patients, endoscopic thyroidectomy via the transoral vestibular approach offers significant advantages over conventional open surgery in minimizing surgical trauma, as evidenced by reduced inflammatory markers, less blood loss and drainage, shorter hospitalization, improved postoperative comfort (less pain), superior cosmetic results, lower incidence of short-term complications. While achieving comparable short-term oncologic outcomes (R0 resection, lymph node yield, ETE rate) to open surgery. However, long-term oncologic outcomes require further validation through studies with extended follow-up.

Acknowledgments

The authors express their appreciation to the staff in The Second People’s Hospital of Liangshan Yi Autonomous Prefecture for their technical assistance.

Footnote

Reporting Checklist: The authors have completed the STROBE reporting checklist. Available at https://gs.amegroups.com/article/view/10.21037/gs-2025-448/rc

Data Sharing Statement: Available at https://gs.amegroups.com/article/view/10.21037/gs-2025-448/dss

Peer Review File: Available at https://gs.amegroups.com/article/view/10.21037/gs-2025-448/prf

Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://gs.amegroups.com/article/view/10.21037/gs-2025-448/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. The study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. This study protocol was reviewed and approved by Ethics Committee of The Second People’s Hospital of Liangshan Yi Autonomous Prefecture (approval No. 202302001). The other participating hospital was also informed of and agreed to this study. Since this study is a retrospective cohort study and the identification information of patients has anonymity, there is no need for informed consent from patients and their families.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

References

1. Zhang C, Gao X, Han Y, et al. Correlation Between Thyroid Nodules and Metabolic Syndrome: A Systematic Review and Meta-Analysis. Front Endocrinol (Lausanne) 2021;12:730279. [Crossref] [PubMed]
2. Nguyen XH, Nguyen XH, Mai TKN, et al. Feasibility and Safety of Endoscopic Thyroidectomy Via a Unilateral Axillobreast Approach for Unilateral Benign Thyroid Tumor in Vietnam. Surg Laparosc Endosc Percutan Tech 2019;29:447-50. [Crossref] [PubMed]
3. Kang YJ, Cho JH, Stybayeva G, et al. Safety and Efficacy of Transoral Robotic Thyroidectomy for Thyroid Tumor: A Systematic Review and Meta-Analysis. Cancers (Basel) 2022;14:4230. [Crossref] [PubMed]
4. Dhoomun DK, Cai H, Li N, et al. Comparison of health-related quality of life and cosmetic outcome between traditional gasless trans-axillary endoscopic thyroidectomy and modified gasless trans-axillary endoscopic thyroidectomy for patients with papillary thyroid microcarcinoma. Cancer Med 2023;12:16604-14. [Crossref] [PubMed]
5. Tae K, Ji YB, Song CM, et al. Robotic and Endoscopic Thyroid Surgery: Evolution and Advances. Clin Exp Otorhinolaryngol 2019;12:1-11. [Crossref] [PubMed]
6. Mo K, Zhao M, Wang K, et al. Comparison of endoscopic thyroidectomy via a modified axillo-breast approach with the conventional breast approach for treatment of unilateral papillary thyroid microcarcinoma. Medicine (Baltimore) 2018;97:e13030. [Crossref] [PubMed]
7. Wongwattana P, Laoveerakul P, Santeerapharp A. A comparison of efficacy and quality of life between transoral endoscopic thyroidectomy vestibular approach (TOETVA) and endoscopic thyroidectomy axillo-breast approach (ETABA) in thyroid surgery: non-randomized clinical trial. Eur Arch Otorhinolaryngol 2021;278:4043-9. [Crossref] [PubMed]
8. Zhou J, Li X, Xia F, et al. Enhanced cosmetic outcomes with central venous catheter drainage in transoral vestibular endoscopic thyroidectomy: a prospective randomized-controlled trial. J Robot Surg 2025;19:498. [Crossref] [PubMed]
9. Xu Z, Song J, Wang Y, et al. A comparison of transoral vestibular and bilateral areolar endoscopic thyroidectomy approaches for unilateral papillary thyroid microcarcinomas. Wideochir Inne Tech Maloinwazyjne 2019;14:501-8. [Crossref] [PubMed]
10. Amin MB, Greene FL, Edge SB, et al. The Eighth Edition AJCC Cancer Staging Manual: Continuing to build a bridge from a population-based to a more "personalized" approach to cancer staging. CA Cancer J Clin 2017;67:93-9.
11. Haugen BR, Alexander EK, Bible KC, et al. 2015 American Thyroid Association Management Guidelines for Adult Patients with Thyroid Nodules and Differentiated Thyroid Cancer: The American Thyroid Association Guidelines Task Force on Thyroid Nodules and Differentiated Thyroid Cancer. Thyroid 2016;26:1-133. [Crossref] [PubMed]
12. Hüscher CS, Chiodini S, Napolitano C, et al. Endoscopic right thyroid lobectomy. Surg Endosc 1997;11:877. [Crossref] [PubMed]
13. Yamaguchi R, Tosaka M, Mukada N, et al. Postoperative Serum C-Reactive Protein and Cerebrospinal Fluid Leakage after Endoscopic Transsphenoidal Surgery. J Neurol Surg B Skull Base 2023;84:578-84. [Crossref] [PubMed]
14. Attallah LM, Bakir SS, Abdulridha MZS, et al. Comparison between CT-Scan Finding and Operative Finding of Patients with Chronic Rhinosinusitis Undergoing Functional Endoscopic Sinus Surgery. Asian Journal of Medicine and Health 2023;21:82-90.
15. Krull E, Lambat Emery S, Viviano M, et al. Assessment of women's sexual quality of life after benign adnexal surgery using vNOTES approach in comparison to conventional laparoscopy: protocol for a randomised controlled trial. BMJ Open 2023;13:e073691. [Crossref] [PubMed]
16. Chand G, Gupta N, Johri G, et al. Natural Orifice Endoscopic Thyroidectomy via Transoral Vestibular Approach (TOVA): Single Surgeon Experience from North India. Indian J Otolaryngol Head Neck Surg 2021;73:160-6. [Crossref] [PubMed]
17. Razavi CR, Shaear M, Anuwong A, et al. The role of surgeon-performed ultrasound in transoral endoscopic thyroidectomy vestibular approach (TOETVA). World J Otorhinolaryngol Head Neck Surg 2020;6:150-4. [Crossref] [PubMed]
18. Guo F, Wang W, Zhu X, et al. Comparative Study Between Endoscopic Thyroid Surgery via the Oral Vestibular Approach and the Areola Approach. J Laparoendosc Adv Surg Tech A 2020;30:170-4. [Crossref] [PubMed]
19. Shen S, Hu X, Qu R, et al. Comparing quality of life between patients undergoing trans-areola endoscopic thyroid surgery and trans-oral endoscopic thyroid surgery. BMC Surg 2021;21:277. [Crossref] [PubMed]
20. Zhou X, Deng J, Xiong J, et al. Factors Influencing the Acceptance of Endoscopic Thyroidectomy Via Oral Vestibular Approach (ETOVA) by Thyroid Surgery Candidates. Surg Laparosc Endosc Percutan Tech 2022;32:554-7. [Crossref] [PubMed]
21. Karakas E, Klein G, Michlmayr L, et al. Transoral thyroid surgery vestibular approach: is there an increased risk of surgical site infections? Updates Surg 2022;74:303-8. [Crossref] [PubMed]
22. Nagata M, Namiki M, Fujikawa T, et al. Prospective randomized trial comparing conventional and underwater endoscopic submucosal dissection for superficial colorectal neoplasms. Endoscopy 2025;57:484-91. [Crossref] [PubMed]
23. Lira RB, De Cicco R, Rangel LG, et al. Transoral endoscopic thyroidectomy vestibular approach: Experience from a multicenter national group with 412 patients. Head Neck 2021;43:3468-75. [Crossref] [PubMed]
24. Kim SY, Kim SM, Makay Ö, et al. Transoral endoscopic thyroidectomy using the vestibular approach with an endoscopic retractor in thyroid cancer: experience with the first 132 patients. Surg Endosc 2020;34:5414-20. [Crossref] [PubMed]