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

Introduction

hyroid nodules are common in general population with 3-7% prevalence1 . The prevalence increases to 19-67% by using high-resolution ultrasonography among randomly selected individuals2 . About 5-15% of thyroid nodules are malignant3 . Based on the 2015 American Thyroid Association guidelines, most of benign thyroid nodules can be observed safely without surgery4 . 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 neck5 . 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 TTOETVA in comparison with open thyroidectomy Sadq G Kadem, Sabah A Mohamd & Zainab T Ibrahim Bas J Surg,June, 27, 2021 18 cosmetic defect6 . Therefore, the need to improve postoperative quality of life, including cosmetics, has increased7 . Gagner M, in 1996, reported feasibility of endoscopic approach to the parathyroid glands8 . 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 wall9-11 . Recently, Transoral endoscopic thyroidectomy has been developed; it is a natural orifice thyroid surgery, minimally invasive and completely scar free12-15 . 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 results16 . 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 surgery17 . 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 extension18,19 . 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) orTOETVA in comparison with open thyroidectomy Sadq G Kadem, Sabah A Mohamd & Zainab T Ibrahim Bas J Surg,June, 27, 2021 19 clindamycin (900 mg) in cases of an allergy to penicillin. The surgical approach of TOETVA, followed the operative steps described by Anuwong A16 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. Figure 1: Photographs of the surgical procedure steps. A: Transverse vestibular incision (10 mm) was made in the midline and extended to the mandible symphysis. B: Sub-platysmal hydrodissection was performed on three axes. C: Blunt dissection of the sub-platysmal plane with a blunt dilator on the same three axes as the hydrodissection. D: A 10 mm central trocar for the camera was placed through the vestibular incision and carbon dioxide insufflation was done. E: Two additional 5 mm trocars were placed through vertical incisions in the most lateral aspects of either side of the vestibule nearest to the edges of the mouth. A B C D ETOETVA in comparison with open thyroidectomy Sadq G Kadem, Sabah A Mohamd & Zainab T Ibrahim Bas J Surg,June, 27, 2021 20 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 (SF36 questionnaire) was used to assess the patient’s satisfaction and burden of surgery on quality of life20 . 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 postoperative pain assessment, results of SF-36 questionnaire for patients satisfaction and quality of life after surgery and length of hospital stay (hour) were also documented. Postoperative complications such as recurrent laryngeal nerve palsy, symptoms of hypocalcemia (paraesthesia, muscle spasm, and Chvostek’s or Trousseau’s signs, confirmed by serum calcium