objective To determine a proper fiducial photography distance setting for ideal amptitied endoscopic imaging of parathyroid gland by high definition endoscopy system.Methods 30 patients were operated with MIVAT mode (modified Miccoli's approach) for treatment of thyroid carcinoma from Apr.2013 to Mar.2014.High definition imaging was established by Image 1 Endoscopy System(Karl Storz Co.) to observe parathyroid gland and related fine anatomical structures during surgery.5 fiducial photography distances (1.0/1.5/2.0/2.5/3.0 cm) were separately tested during surgery.Maximally amplified parathyroid gland images of each setting were obtained by the approaching-amplifying photographic method,and then the size of the real parathyroid glands as well as their screen images were measured and recorded to calculate the magnification.A proper fiducial photography distance setting was determined postoperatively by comparison of the magnification times,as well as clarity,stability of the imaging and surgical maneuverability.Results ①90 parathyroid glands were successfully observed and measured.②At the longest fiducial photography distance (3.0 cm),the parathyroid gland could be stably magnified by 14.26±3.06(long trail)/12.62±2.88 (wide trail)times,but their contour and color not clear.③At the intermediate distance (2.5 cm),the parathyroid gland could be magnified by 16.74±3.15 (long trail)/14.81± 3.47(wide trail)times with the graphics stable,and the color and contour more clear,but the vascular pedicle and the tiny vessels under the capsule still blurred.④At the shortest distance (1.0 cm),the parathyroid gland could be magnified by 27.72±6.45 (long trail)/26.33±7.22(wide trail)times,not only the color and contour,but also the vascular pedicle and the tiny vessels under the capsule of the gland became further clearer,unfortunately the graphics was shimmy and unstable.Conclusions ①2.5 cm can be a proper fiducial photography distance for searching,identifying and preserving parathyroid gland in MIVAT,while 1.0 cm can be a special fiducial photography distance for further confirming parathyroid gland when necessary.② Current high definition endoscopy system can be applied to identify the parathyroid gland if fiducial photography distance was properly set and approachingamplifying photographic method was used.Along with the magnification of the imaging,the features of the parathyroid gland may become clearer,including its yellow-brown color and oval contour,as well as the detail structures such as the tiny vessels under the capsule and the vascular pedicle.

Hyperparathyroidism is an important complication of thyroid surgery.Identification is the premise of intraoperative pretection.At present,identification of the parathyroid gland relies on personal experience of surgeons.Amplifying display of endoscope or surgical magnifying glass,the use of dyeing agent such as methylene blue,nanocarbon,5-ALA or BB5-G1,the use of radionuclide imaging and contact endoscope,and biopsy like intraoperative frozen pathological examination and FNA are all important trials.This article is going to make a review of the methods.

Objective:To explore superior mediastinal lymph node zoning of thyroid cancer for accurate anatomical definition as a reference for surgical access. Methods:A method for zoning superior mediastinal lymph nodes for thyroid cancer was proposed. From Sep 2018 to Nov 2019, 36 cases of thyroid cancer with superior mediastinal lymph nodes metastases were reviewed. The diagnosis, surgical approaches, pathology, characteristics of lymph node metastasis, complications and follow-up results were analyzed.Results:The superior mediastinal lymph nodes were grouped into 10 areas: 1, 2Ra, 2Rb, 2La, 2Lb, 3A, 3P, 4R, 4La and 4Lb. According to the location of the superior mediastinum metastatic lymph nodes, direct vision approach through the neck incision, laparoscope-assisted approach, thracoscepy, laparoscope-assisted combined with thrascopy approach or conventional median sternotomy was performed for regional lymph node dissection. The average follow-up time was (10±4) months. No residual or recurrence of tumor in superior mediastinal area was found.Conclusions:The zoning of the superior mediastinal lymph nodes in thyroid cancer can be used as a guide for surgical approach to lymph node dissection .

Objective To investigate the safety and feasibility of modified gasless trans-subclavian approach endoscopic total thyroidectomy for papillary thyroid carcinoma(PTC).Methods We retrospectively analyzed the clinical data of consecutive 82 patients with PTC who underwent the modified gasless trans-subclavian approach endoscopic total thyroidectomy in the Department of Head and Neck Surgery,Sir Run Run Shaw Hospital,Affiliated with the Zhejiang University School of Medicine,from March 2022 to June 2023.Results All operations were successfully completed under endoscopy approach without transfer to open surgery.The maximum diameter of PTC was(6.6±5.4)mm.The operation duration was(156.5±32.7)min,and the number of lymph nodes in the central compartment was(12.3±6.4).The postoperative hospital stay was(3.3±1.2)d.Postoperative complications included two cases of transient hypoparathyroidism and six cases of transient recurrent laryngeal nerve injury.All the patients recovered in one month.One case of postoperative bleeding was observed.No permanent laryngeal nerve injury,permanent hypoparathyroidism or incision infection occurred.Conclusion The gasless trans-subclavian approach endoscopic total thyroidectomy is a feasible and safety approach in selected PTC patients.The lymph nodes in the central compartment are thoroughly dissected.This approach has obvious advantages in functional protection of the anterior cervical region,and has clinical application value.

Objective:To study the safety and feasibility of gasless transoral endoscopic thyroidectomy though vestibular approach using self-retaining retractor for papillary thyroid carcinoma.Methods:The clinical data of 39 papillary thyroid carcinoma patients undergoing gasless transoral endoscopic thyroidectomy were collected at Department of Head and Neck Surgery, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine from Nov 2020 to Jun 2021.Results:All cases successfully underwent laparoscopic surgery without conversion to open surgery. The mean duration of operation was (142±35) min, and the postoperative mean hospital stay was (4.1±0.8) days. The mean maximum diameter of the tumor was (8.5±4.5) mm, and the mean number of lymph node harvest of by central compartment dissection was 7.7±5.9. Postoperative complications were transient hypoparathyroidism in 2 cases but recovered in 1 month. Scalp hydrop in 1 patient,fading subsequently. Transient sensory change around the lower lip in 3 cases, which recovered in 6 months. No patient suffered from recurrent laryngeal nerve palsy or hematoma, no permanent hypoparathyroidism occurred, nor of the postoperative bleeding .Conclusion:The gasless transoral endoscopic thyroidectomy viaoral vestibular approach is a feasible approach in selected papillary thyroid carcinoma patients.

Objective:To establish a predictive model of lateral lymph node metastasis in patients with papillary thyroid carcinoma(PTC), and further to compare the diagnostic efficiency of this model with the suspected abnormal lymph node thyroglobulin in fine-needle aspirate fluid (FNA-Tg) for lateral lymph node metastasis.Methods:The preoperative clinical and ultrasonographic data of 110 patients (257 lymph nodes) who underwent PTC cervical lymph node dissection were retrospectively analyzed. According to the postoperative pathological results, they were divided into lateral lymph node metastasis and non-metastasis group. Regression analysis was used to screen out independent risk factors affecting lateral lymph node metastasis and establish a predictive model. The ROC curve was used to evaluate the diagnostic efficacy and the best diagnostic cut-off point.Results:Prediction model: Logit( P)=-2.987+ 2.189(S/L ratio of lymph nodes)+ 1.748(hilum absent)+ 2.030(hyperechoic)+ 1.849(vascular abnormalities). The sensitivity, specificity, accuracy and AUC of the prediction model in the diagnosis of lateral lymph node metastasis were 92.1%, 83.9%, 87.9% and 0.929, respectively. The Homser-Lemeshow goodness of fit test showed that the Logistic model has a good fitting effect. The sensitivity, specificity, accuracy, and AUC of FNA-Tg in the diagnosis of lateral lymph node metastasis were 87.4%, 95.4%, 90.3% and 0.968, respectively. The sensitivity, specificity, accuracy, and AUC of the combined diagnosis of the predictive model and FNA-Tg were 92.9%, 96.9%, 94.2% and 0.989, respectively. Conclusions:The model has a good predictive value for PTC cervical lymph node metastasis. Combined with FNA-Tg, it can improve its diagnostic efficiency and provide more valuable information for the decision-making of clinical surgical procedures.

Objective: To evaluate the correlation between ultrasound features of papillary thyroid carcinoma (PTC) and lymph node metastasis by preoperative ultrasound elemental observation of thyroid nodules. Methods: Three hundred and seventy-six patients who underwent primary thyroid surgery and confirmed by ultrasound and pathological data as single-focal PTC from Jannary to December 2017 in Sir Run Run Shaw Hospital of Zhejiang Univbersity College of Medicine were retrospectively analyzed. According to the presence or absence of lymph node metastasis, they were divided into central and lateral lymph node metastasis group and non-metastasis group. Independent risk factors for central lymph node metastasis (CLNM) and lateral lymph node metastasis (LLNM) were analyzed by χ² test and multivariate Logistic regression. Results: Multivariate analysis showed that the posterior margin of the cancer was <0.25 cm from the posterior wall of the thyroid gland as an independent risk factor for CLNM (P=0.025). Compared with the tumor volume ≤0.38 cm³, the cancer volume >0.38 cm³ (P=0.000), was more prone to CLNM. And multivariate analysis showed that the anterior margin of the cancer was <0.17 cm (P=0.006) from the anterior thyroid capsule and the inner wall of the foci was <0.26 cm (P=0.014) as independent risk factors for LLNM. Compared with the maximum diameter of the tumor lesion ≤1 cm, the maximum diameter >2 cm (P=0.001) group was more prone to LLNM. Compared with the tumor volume ≤0.38 cm³, the tumor volume >0.38 cm³ (P=0.000) was more prone to LLNM. Conclusions The larger volume of single focal PTC carcinoma and the closer to the posterior thyroid capsule are independent risk factors for CLNM. The larger volume and diameter of single focal PTC, and the closer to the anterior and medial wall capsule are independent risk factors for LLNM.