OUTCOME OF TRANSORAL ENDOSCOPIC THYROIDECTOMY VESTIBULAR APPROACH (TOETVA) IN COMPARISON WITH OPEN THYROIDECTOMY FOR BENIGN THYROID NODULES

Open thyroidectomy; is the gold standard surgical procedure for thyroid diseases, but the incision scar in the anterior aspect of the neck due to this approach cannot be avoided and may results in a permanent cosmetic defect. Therefore, there is a need to improve postoperative quality of life, including cosmetics. Recently, transoral endoscopic thyroidectomy has been developed; it is a natural orifice thyroid surgery, minimally invasive and completely scar free. This study aimed to describe the outcome, patient’s satisfaction, and complications after hemithyroidectomy for benign thyroid nodules by transoral endoscopic vestibular approach in comparison with open approach. This study was conducted in Al-Shiffa General hospital, Basrah, Iraq from August 2017 to June 2019 and was approved by a local ethical committee. Fifty patients with benign thyroid nodules who are candidate for hemithyroidectomy were included in the study; they were divided into two groups according to the method for thyroidectomy which was either conventional open or transoral endoscopic thyroidectomy vestibular approach based on the patients’ preferences. All operations were performed by the same surgical team. The results of this study showed that 24 (48%) of them operated upon by transoral endoscopic thyroidectomy vestibular approach, while the remaining 26 (52%) patients have been operated upon by open thyroidectomy approach. Transoral endoscopic thyroidectomy vestibular approach reported significant longer operative time, has comparable rate of complications with an excellent cosmetic outcome and better postoperative patients’ satisfaction in comparison to open thyroidectomy. In conclusion, transoral endoscopic thyroidectomy vestibular approach is a safe and feasible procedure with an excellent cosmetic outcome and better patients’ satisfaction. At present, it is a relatively time-consuming procedure and, therefore, candidate patients with a strong motivation for scar free surgery are recommended.


Introduction
hyroid nodules are common in general population with 3-7% prevalence 1 . The prevalence increases to 19-67% by using high-resolution ultrasonography among randomly selected individuals 2 . About 5-15% of thyroid nodules are malignant 3 . Based on the 2015 American Thyroid Association guidelines, most of benign thyroid nodules can be observed safely without surgery 4 . Indications for surgical treatment in benign thyroid nodules are; indeterminate or suspicious fine needle aspiration cytology for malignancy, compressive signs and symptoms, excessive thyroid hormone producing nodule, and patient preference in case of thyroid nodule producing visible mass in the neck 5 . Open thyroidectomy is the gold standard surgical treatment for thyroid diseases, but the incision scar in the anterior aspect of the neck due to this approach cannot be avoided and may results in a permanent T cosmetic defect 6 . Therefore, the need to improve postoperative quality of life, including cosmetics, has increased 7 . Gagner M, in 1996, reported feasibility of endoscopic approach to the parathyroid glands 8 . After that, a number of techniques simultaneously started being called as minimally invasive thyroid surgery. These can be classified as pure endoscopic techniques and video-assisted techniques. All these methods still leaving a scar in the endoscopic port's site entry; in the neck, axilla, breast or chest wall [9][10][11] . Recently, Transoral endoscopic thyroidectomy has been developed; it is a natural orifice thyroid surgery, minimally invasive and completely scar free [12][13][14][15] . The refinement of this transoral thyroidectomy technique was wellestablished and described by Anuwong A, as the transoral endoscopic thyroidectomy vestibular approach (TOETVA) with excellent clinical results 16 . In a systemic review of 15 studies; TOETVA have a comparable rate of complications to that of conventional open thyroidectomy, but unfortunately this new approach may be associated with new complications; mental nerve palsy, cervical and/or mediastinal emphysema, conversion to open thyroidectomy, and because it is a clean contaminated surgery, it may be associated with an increase rate of deepseated neck infection, although the reported incidence of these complications was rare, they are considered as an additional complications added to the field of thyroid surgery 17 . Currently accepted patient selection criteria for TOETVA are; strong motivation for scar free surgery, thyroid gland diameter ≤10 cm or dominant nodule diameter ≤5 cm in ultrasonography, a benign disease as (thyroid cyst or nodular goiter), follicular neoplasm, micropapillary thyroid cancer or differentiated thyroid cancer ≤ 2cm without lymph node metastasis or extrathyroidal extension 18,19 .
In this study we describe the outcome, patient's satisfaction, and complications after hemithyroidectomy for benign thyroid nodules by transoral endoscopic vestibular approach in comparison with open approach.

Patients and Methods
This study was conducted in Al-Shiffa General hospital, Basrah, Iraq from August 2017 to June 2019 and was approved by a local ethical committee. Fifty patients with benign thyroid nodules who are candidates for hemithyroidectomy were included in the study and were divided into two groups according to the method of thyroidectomy which was either conventional open (OT group) or TOETVA (ET group) based on the patients' preferences. All participants were provided with the particular details for their surgeries and only patients with strong motivation for scar free surgery were selected for TOETVA procedure. Informed consent was obtained from each patient. All patients were operated upon by the same surgical team. Inclusion criteria included; female patients with unilateral thyroid nodularity (solitary or dominant thyroid nodule) with a diameter less than 5cm, FNA (Bethesda II), BMI less than 30 with no hyperthyroidism, no thyroiditis, no history of previous thyroid surgery or neck irradiation, and have postoperative follow-up period ≥ 12 weeks.

Operative techniques:
All patients were admitted to the hospital one day pre-surgery for routine investigations and preparation for general anesthesia.
A flexible fiber-optic laryngoscopy was performed to confirm normal recurrent laryngeal nerve function. During induction of general anesthesia with endotracheal intubation through the mouth, the patient was put in supine position with the neck extended. Patient received intravenous prophylactic antibiotics, either amoxicillin (1 g) or clindamycin (900 mg) in cases of an allergy to penicillin. The surgical approach of TOETVA, followed the operative steps described by Anuwong A 16 as shown in Figure 1. Following washing of the oral cavity with diluted povidone iodine and normal saline, a 10 mm transverse vestibular incision was made in the midline and extended in depth up to the mandible symphysis [ Figure 1A]. Using a Verse needle, sub-platysmal hydrodissection with approximately 20 mL of normal saline with adrenaline (500 mL normal saline+1 mL adrenaline) was performed in three axes (central, right and left) [ Figure 1B]. Blunt dissection of the subplatysmal plane with a blunt dilator was performed in the same three axes as the hydrodissection [ Figure 1C]. A 10 mm central trocar for the camera was placed through the vestibular incision and insufflation was performed up to 5-6 mmHg with carbon dioxide [ Figure 1D]. Two additional 5 mm trocars were placed under direct vision through two 5 mm vertical incisions in the most lateral aspects of either side of the vestibule nearest to the edges of the mouth [ Figure  1E]. Using an ultrasonic energy device SONICBEAT, USG 400 (Olympus, Tokyo, Japan) to dissect and divide the tissue and blood vessels. The peritracheal fascia was divided in the midline as in open thyroidectomy approach. Using a hanging sutures passing through the skin, the strap muscles were retracted laterally. The thyroid isthmus was dissected and transected. All thyroid blood vessels were divided as close to the thyroid as possible. Intraoperative neuromonitoring for the recurrent laryngeal nerve is not practised in Al-Shifaa General Hospital and therefore, anatomical landmarks were used to identify and preserve this nerve. Parathyroid glands were identified and preserved. After complete excision of thyroid lobe, the specimen was removed using an endobag via the 10 mm vestibular incision and sent for histopathology analysis. Closure of the peritracheal fascia was performed using absorbable sutures and the vestibular wounds were closed in two layers with absorbable sutures.  In patients subjected to conventional open thyroidectomy; a collar skin incision done mid-way between suprasternal notch and thyroid notch and extended from one sternomastoid muscle to another, creation of subplatismal flaps, vertical incision of pretracheal facia and separation of strap muscles and mobilization of thyroid lobe.
Using an ultrasonic energy device SONICBEAT, USG 400 (Olympus, Tokyo, Japan) for sealing and division of blood vessels and for dissection and excision of thyroid lobe. At the end of the procedure; the wound closed in layers.
During removal of the endotracheal tube, the vocal cords were re-examined with flexible fibreoptic laryngoscopy to confirm normal function of the recurrent laryngeal nerve. Following recovery from anesthesia, patients were transferred to the surgical ward for observation, all patients were given analgesia in form of Diclofenac injection (75mg IM) shortly after reaching the surgical ward, after that all patients were re-evaluated at the night tour and only patients with pain were given analgesia in form of Tramadol injection (50mg IM). The visual analogue scale (VAS) was used for postoperative pain assessment (0 to 10 scale); no pain=0, mild pain=1-3, moderate pain=4-6 and severe pain=7-10. The pain assessment have been done by the same resident doctor during the night tour and then during the morning tour of the first postoperative day. Intravenous antibiotics were continued until the patients were discharged from hospital. The patients were discharged from hospital when the vital signs are within normal range; the patient could manage an oral diet and had been given instructions to continue oral antibiotics and mouthwash (in case of TOETVA patient) for one week. Patients were reexamined at the end of the first postoperative week, then after four, eight and twelve weeks, at which time flexible fibreoptic laryngoscopy was again performed to evaluate vocal cord function and ultrasound examination of cervical region performed to evaluate seroma and hematoma formation. At the end of follow-up period, the Arabic version of 36-Item Short Form Health Survey (SF-36 questionnaire) was used to assess the patient's satisfaction and burden of surgery on quality of life 20 . The following domains were evaluated via an in-clinic interview: physical functioning; bodily pain; general health; vitality; social functioning; roleemotional; mental health. The following data were recorded perioperatively: patients' demographics, clinical diagnosis, preoperative thyroid ultrasound findings, postoperative cervical region ultrasound findings, histopathology results, and flexible fiberoptic laryngoscopy for vocal cord examination before and after operation. In addition, surgical procedure details and outcome such as duration of surgery in minutes (calculated from start of skin or mucous membrane incision to end of wound closure), results of the visual analogue scale (VAS) for

Results
The total number of hemithyroidectomies that performed in this study were 50 cases; 24 (48%) of them have been operated with TOETVA (ET group), while the remaining 26 (52%) patients have been operated with open approach (OT group). The patient's characteristics of both groups are shown in table I.  Table II shows the details of the outcome of both procedures. Regarding the complications, 2 cases of temporary recurrent laryngeal nerve palsy were reported in this study, 1(4.16%) case in ET group and 1(3.84%) case in OT group, with no significant statistical difference (P=1.000). both of these cases treated conservatively and resolved completely within 8 weeks. Other reported complications in this study which were unique for ET group, these were temporary mental nerve palsy in 1 case (4.16%,) which treated conservatively and resolved completely within few weeks, cervical subcutaneous emphysema in 1 case (4.16%,), this case also treated conservatively and resolved completely within 24 hours, another unique complication for ET group was the conversion to open thyroidectomy in 1 case (4.16%,) due to uncontrolled intraoperative bleeding. Other complications, like seroma, hematoma, permanent recurrent laryngeal nerve palsy, permanent mental nerve palsy, hypocalcemia, mediastinal emphysema and postoperative bleeding or mortality were not reported in this study.

Discussion
All patients in this study were females with unilateral benign uncomplicated thyroid pathology and all patients who were selected for TOETVA procedure were young, normal BMI and most of them have right thyroid nodule with mean size (3.6±0.443). These patients' characteristics go with the published selection criteria for beginner TOETVA surgeon to avoid complications 21 . Regarding the outcome of both procedures, ET group had a significantly longer operative time, this may because of the extra time needed to create the working space and port insertion and because of the narrow working space, the operation was more difficult. Most other studies comparing ET and OT had similar results [22][23][24][25] . This longer operative time may decrease after a learning curve [26][27][28] . Although most studies that compare TOETVA to open thyroidectomy and to other endoscopic thyroidectomy approaches reported less postoperative pain in TOETVA patients [29][30][31][32][33][34] . In our study, we reported same level of postoperative pain in both groups, but there is difference in the site of the pain, TOETVA patients complained of pain in the upper aspect of the neck whereas patients operated upon with open thyroidectomy procedure complained of pain at the lower aspect of the neck. This result was similar to the result reported by Jonathon et al 35 .
Regarding patient's satisfaction after surgery, patients operated with TOETVA procedure reported better satisfaction in comparison to patients operated with open procedure. The conventional incision used for open thyroidectomy yields a very exposed surgical site, and can result in cosmetically unfavorable outcome which may lead to social and emotional disturbance in addition to the pain and itching resulted from any surgical scar. Our results goes with results of several studies that were conducted in an effort to address the issue of visible scars left by open and endoscopic techniques [36][37][38] . Regarding postoperative complications, recurrent laryngeal nerve injury remains the most fearful complications of thyroid surgery 39 . In our study we reported same incidence of recurrent laryngeal nerve palsy in both procedures which goes with the results of the systemic review published by Camenzuli et al 17 .
Conclusion; TOETVA is a safe and feasible procedure with an excellent cosmetic outcome and better patients' satisfaction. At present, it is a relatively time-consuming procedure and therefore, candidate patients with a strong motivation for scar free surgery are recommended.