Usefulness of ICG Angiography-Guided Thyroidectomy for Preserving Parathyroid Function.

INTRODUCTION: Hypoparathyroidism is the most frequent complication after total thyroidectomy and, when permanent, it becomes a severe chronic disease. We assessed the usefulness of indocyanine green (ICG) angiography-guided thyroidectomy to reduce the postoperative hypocalcemia. METHODS: Prospective study with two consecutive cohorts of patients who underwent total thyroidectomy: historical control group (CG) and angiography-guided thyroidectomy group (AG). In all patients, ICG-angiography was performed at the end of the surgery to predict immediate parathyroid gland (PG) function. In the AG, ICG-angiography was also done after PG identification to show their vascular supply. We compared the rate of postoperative hypocalcemia (calcium supplementation needed due to hypocalcemia symptoms or calcium levels < 1.8 mmol/L on the first postoperative day) and permanent hypocalcemia (need of calcium ± vitamin D supplementation 12 months after thyroidectomy). RESULTS: We included 120 consecutive patients (84 CG; 36 AG). Thyroid cancer was the most common diagnostic (63.1% CG-69.4% AG; p = 0.646) and central neck dissection was also frequent (54.8% CG-64.3% AG; p = 0.468). The AG developed a lower rate of postoperative (26.2-5.6%; p = 0.011) and permanent hypocalcemia (11.9-0%; p = 0.032). The OR for permanent hypocalcemia was 0.673 (95% CI 0.591-0.766). A significant higher rate of well vascularized PG at the end of the surgery (score 2) in the AG (39.2-52.9%; p = 0.018) was also seen. CONCLUSION: ICG angiography-guided thyroidectomy is a useful tool to identify PG vascularization, allowing a better PG preservation and a significant decrease in hypocalcemia rates.

The value of clinical-ultrasonographic feature model to predict the severity of secondary hyperparathyroidism.

OBJECTIVES: To analyze conventional ultrasound (CUS) and contrast-enhanced ultrasound (CEUS) features in patients with secondary hyperparathyroidism (SHPT) and to evaluate the clinical-ultrasonographic feature based model for predicting the severity of SHPT. METHODS: From February 2016 to March 2021, a total of 59 patients (age 51.3 ± 11.7 years, seCr 797.8 ± 431.7 µmol/L, iPTH 1535.1 ± 1063.9 ng/L) with SHPT (including 181 parathyroid glands (PTGs)) without the history of intact parathyroid hormone (iPTH)-reducing drugs using were enrolled. The patients were divided into the mild SHPT group (mSHPT, iPTH <800 ng/L) and the severe SHPT group (sSHPT, iPTH ≥ 800 ng/L) according to the serum iPTH level. The clinical test data of patients were collected and CUS and CEUS examinations were performed for every patient. Multivariable logistic regression model according to clinical-ultrasonographic features was adopted to establish a nomogram. We performed K-fold cross-validation on this nomogram model and nomogram performance was determined by its discrimination, calibration, and clinical usefulness. RESULTS: There were 19 patients in the mSHPT group and 40 patients in the sSHPT group. Multivariable logistic regression indicated serum calcium, serum phosphorus and total volume of PTGs were independent predictors related with serum iPTH level. Even though CEUS score of wash-in and wash-out were showed related to severity of SHPT in univariate logistic regression analysis, they were not predictors of SHPT severity (p = 0.539, 0.474 respectively). The nomogram developed by clinical and ultrasonographic features showed good calibration and discrimination. The accuracy and the area under the curve (AUC), positive predictive value (PPV), negative predictive value (NPV) and accuracy of this model were 0.888, 92.5%, 63.2% and 83.1%, respectively. When applied to internal validation, the score revealed good discrimination with stratified fivefold cross-validation in the cohort (mean AUC = 0.833). CONCLUSIONS: The clinical-ultrasonographic features model has good performance for predicting the severity of SHPT.

The anatomical basis for preserving the blood supply to the parathyroids during thyroid surgery, and a review of current technologic advances.

BACKGROUND: Devascularization of the parathyroid glands is generally accepted as the most common mechanism for iatrogenic hypocalcemia, a frequently seen complication of both total and completion thyroidectomy procedures. Much has been written about iatrogenic hypoparathyroidism, but few papers have precisely delineated the arterial supply of the parathyroid glands and the common anatomical variations that may impact parathyroid preservation during thyroid surgery. METHODS: We offer an illustrated review and discussion of the only two anatomic studies published in the medical literature focusing on parathyroid vasculature. In addition, we examine current techniques of parathyroid identification, preservation, and classification. FINDINGS: A surgical technique that preserves the parathyroid arteries is vital to preserving the viability of the parathyroid gland(s) during thyroid surgery. In 1907, Halsted and Evans described a technique of ligating the distal branches of the thyroid arteries beyond the origin of the parathyroid arteries, a technique termed ultra-ligation. In 1982, Flament et al.. reported three distinct anatomical variations of the parathyroid arteries which place the parathyroid blood supply at risk for devascularization during thyroid surgery. Our review also highlights novel techniques that aid surgeons in identification and assessment of the parathyroid glands. CONCLUSIONS: Recognition of the variations of parathyroid anatomy and their potential to lead to devascularization aids thyroid surgeons in their pursuit of parathyroid preservation. An awareness of the variety of novel parathyroid identification and preservation techniques can assist surgeons to achieve this goal.

In Situ Preservation of Parathyroid Gland With Vasculature for Papillary Thyroid Carcinoma Is Associated With Higher PTH Levels After Total Thyroidectomy.

PURPOSE: To evaluate the impact of parathyroid gland vasculature preservation in-situ technique (PGVPIST) on postoperative parathyroid hormone (PTH) and calcium plasma levels in thyroid patients undergoing total thyroidectomy for papillary thyroid carcinoma (PTC). STUDY DESIGN: Retrospective cohort study. METHODS: Patients with PTC who underwent total thyroidectomy by either the conventional technique (group 1, January 2019 to January 2020) or PGVPIST (group 2, January 2020 to January 2021) were compared. Postoperative blood calcium levels and PTH levels were assessed in these groups. RESULTS: Totally 149 patients with consecutive PTC underwent total thyroidectomy, including 60 patients in group 1 and 89 patients in group 2. Postoperative serum calcium levels in group 1 were insignificantly lower than in group 2 at day 1 (2.18 ± 0.02 vs 2.15 ± 0.01 mmol/L) and day 30 (2.27 ± 0.02 vs 2.38 ± 0.11) after surgery. But postoperative serum PTH levels in group 1 were significantly lower than that in group 2 at day 1 (23.68 ± 2.54 vs 31.46 ± 2.11 pg/mL) and day 30 (45.63 ± 3.21 vs 55.65 ± 2.89 pg/mL) after surgery. CONCLUSION: Parathyroid gland vasculature preservation in-situ technique for PTC is associated with higher PTH level after total thyroidectomy. The parathyroid gland vasculature mostly strongly adheres with adjacent thyroid parenchyma. Therefore, deferred processing of tiny thyroid parenchyma of parathyroid gland vessels is essential to prevent devascularization.

Assessing Intraoperative Laser Speckle Contrast Imaging of Parathyroid Glands in Relation to Total Thyroidectomy Patient Outcomes.

Background: Accurate assessment of parathyroid gland vascularity is important during thyroidectomy to preserve the function of parathyroid glands and to prevent postoperative hypocalcemia. Laser speckle contrast imaging (LSCI) has been shown to be accurate in detecting differences in parathyroid vascularity. In this surgeon-blinded prognostic study, we evaluate the relationship between intraoperative LSCI measurements and postoperative outcomes of total thyroidectomy patients. Methods: Seventy-two thyroidectomy patients were included in this study. After thyroid resection, an LSCI device was used to image all parathyroid glands identified, and a speckle contrast value was calculated for each. An average value was calculated for each patient, and the data were grouped according to whether the patient had normal (16-77 pg/mL) or low levels of parathyroid hormone (PTH) measured on postoperative day 1 (POD1). The aim of this study was to establish a speckle contrast threshold for classifying a parathyroid gland as adequately perfused and to determine how many such glands are required for normal postoperative parathyroid function. Results: A speckle contrast limit of 0.186 separated the normoparathyroid and hypoparathyroid groups with 87.5% sensitivity and 84.4% specificity: 7 of 8 patients with low PTH on POD1 had an average parathyroid speckle contrast above this limit, while 54 of 64 patients with normal postoperative PTH had an average parathyroid speckle contrast below this limit. Taking this value as the threshold for adequate parathyroid perfusion, it was determined that only one vascularized gland was needed for normal postoperative parathyroid function: 64 of 69 patients (92.8%) with at least one vascularized gland (determined by LSCI) had normal postoperative PTH, while all 3 patients (100%) with no vascularized glands had low postoperative PTH. Overall, the rates of temporary and permanent hypoparathyroidism in this study were 8.3% and 1.4%, respectively. Conclusions: LSCI is a promising technique for assessing parathyroid gland vascularity. It has the potential to help reduce the incidence of hypocalcemia after thyroidectomy by providing surgeons with additional information during surgery to aid in the preservation of parathyroid function.

A Novel and Generic Workflow of Indocyanine Green Perfusion Assessment Integrating Standardization and Quantification Toward Clinical Implementation.

OBJECTIVE: This study aims to generate a reproducible and generalizable Workflow model of ICG-angiography integrating Standardization and Quantification (WISQ) that can be applied uniformly within the surgical innovation realm independent of the user. SUMMARY BACKGROUND DATA: Tissue perfusion based on indocyanine green (ICG)-angiography is a rapidly growing application in surgical innovation. Interpretation of results has been subjective and error-prone due to the lack of a standardized and quantitative ICG-workflow and analytical methodology. There is a clinical need for a more generic, reproducible, and quantitative ICG perfusion model for objective assessment of tissue perfusion. METHODS: In this multicenter, proof-of-concept study, we present a generic and reproducible ICG-workflow integrating standardization and quantification for perfusion assessment. To evaluate our model's clinical feasibility and reproducibility, we assessed the viability of parathyroid glands after performing thyroidectomy. Biochemical hypoparathyroidism was used as the postoperative endpoint and its correlation with ICG quantification intraoperatively. Parathyroid gland is an ideal model as parathyroid function post-surgery is only affected by perfusion. RESULTS: We show that visual subjective interpretation of ICG-angiography by experienced surgeons on parathyroid perfusion cannot reliably predict organ function impairment postoperatively, emphasizing the importance of an ICG quantification model. WISQ was able to standardize and quantify ICG-angiography and provided a robust and reproducible perfusion curve analysis. A low ingress slope of the perfusion curve combined with a compromised egress slope was indicative for parathyroid organ dysfunction in 100% of the cases. CONCLUSION: WISQ needs prospective validation in larger series and may eventually support clinical decision-making to predict and prevent postoperative organ function impairment in a large and varied surgical population.

Detection of parathyroid adenomas with multiphase 4DCT: towards a true four-dimensional technique.

BACKGROUND: Four-dimensional computed tomography (4DCT) is a commonly performed examination in the management of primary hyperparathyroidism, combining three-dimensional imaging with enhancement over time as the fourth dimension. We propose a novel technique consisting of 16 different contrast phases instead of three or four different phases. The main aim of this study was to ascertain whether this protocol allows the detection of parathyroid adenomas within dose limits. Our secondary aim was to examine the enhancement of parathyroid lesions over time. METHODS: For this prospective study, we included 15 patients with primary hyperparathyroidism and a positive ultrasound prior to surgery. We performed 4DCT with 16 different phases: an unenhanced phase followed by 11 consecutive arterial phases and 4 venous phases. Continuous axial scanning centered on the thyroid was performed over a fixed 8 cm or 16 cm coverage volume after the start of contrast administration. RESULTS: In all patients, an enlarged parathyroid lesion was demonstrated, and the mean lesion size was 13.6 mm. The mean peak arterial enhancement for parathyroid lesions was 384 Hounsfield units (HU) compared to 333 HU for the normal thyroid. No significant difference could be found. The time to peak (TTP) was significantly earlier for parathyroid adenomas than for normal thyroid tissue: 30.8 s versus 32.3 s (p value 0.008). The mean slope of increase (MSI) of the enhancement curve was significantly steeper than that of normal thyroid tissue: 29.8% versus 22.2% (p value 0.012). The mean dose length product was 890.7 mGy cm with a calculated effective dose of 6.7 mSv. CONCLUSION: Our 4DCT protocol may allow better visualization of the pattern of enhancement of parathyroid lesions, as enhancement over time curves can be drawn. In this way, wash-in and wash-out of contrast in suspected lesions can be readily demonstrated. Motion artifacts are less problematic as multiple phases are available. Exposure to our proposed 4DCT technique is comparable to that for classic helical 4DCT. Careful selection of parameters (lowering kV and SNR) can help to further reduce the dose.

Location and Vascular Classification of 188 parathyroid glands in New Zealand White Rabbits / [Localização e Classificação Vascular de 188 glândulas paratireoidianas em coelhos brancos da Nova Zelândia]

The function and protection of the parathyroid glands are increasingly popular research topics. New Zealand white rabbits are the most commonly used animal model of parathyroid ischemia. However, information on the vasculature of their parathyroid glands is limited. We used 94 healthy New Zealand white rabbits, 3-4 months of age and 2-3kg in weight, for exploration of the parathyroid glands, which were stained using hematoxylin and eosin (HE) after removal. The following types were classified according to the relationship between the position of the inferior parathyroid gland and the thyroid: Type A, Close Type, Type B, and Distant Type. There were 188 cases, 4 where the inferior parathyroid glands were located near the dorsal side of thyroid (2.13%), 8 where the inferior parathyroid glands were located superior to the upper pole of the thyroid (4.26%), 20 where the inferior parathyroid glands were located parallel to the thyroid (10.64%), and 155 cases where the inferior parathyroid glands were located inferior to the lower pole of thyroid (82.45%). Identifying the location and classifying the vasculature of the parathyroid glands in New Zealand white rabbits will provide an anatomical model to assist in future research.(AU)

A função e proteção das glândulas paratireoidianas é um tópico de pesquisa cada vez mais popular. Coelhos brancos da Nova Zelândia são o modelo animal mais comumente usada para isquemia da paratireóide. Porém, informação sobre a vasculatura de suas glândulas paratireóides é limitada. Foram usados 94 coelhos brancos da Nova Zelândia saudáveis, com 3-4 meses de idade, 2-3kg de peso, para exploração das glândulas paratireóides, que foram coradas com hematoxilina e eosina (HE) após a remoção. Os seguintes tipos foram classificados de acordo com a relação entre a posição da glândula paratireoidiana inferior e a tireoide: Tipo A, Tipo Próximo, Tipo B e Tipo Distante. Houve 188 casos, 4 em que as glândulas paratireoidianas inferiores estavam localizadas próximas ao lado dorsal da tireoide (2.13%), 8 onde as glândulas paratireoidianas inferiores estavam localizadas superiores ao polo superior da tireoide (4.26%), 20 onde as glândulas paratireoidianas inferiores estavam localizadas paralelo à tireoide (10.64%) e 155 casos em que as glândulas paratireoidianas inferiores estavam localizadas inferiores ao polo inferior da tireoide (82.45%). A identificação da localização e a classificação da vasculatura das glândulas paratireóides em coelhos brancos da Nova Zelândia fornecerão um modelo anatômico para auxiliar em pesquisas futuras.(AU)

Identification of the recurrent laryngeal nerve during thyroidectomy can affect the complication rate.

AIM: Identification of recurrent laryngeal nerve (RLN), performed via different techniques, decreases nerve injury during thyroidectomy. We aimed to evaluate the effect of different anatomic levels at which RLN was identified on postoperative complications. MATERIAL AND METHODS: The patients underwent total thyroidectomy or lobectomy without lymph node dissection were included. Two different surgical methods were performed: thyroidectomy identifying RLN at level of inferior thyroid artery (ITA) (Group 1); at level of Berry's ligament (Group 2). Patients were evaluated with indirect laryngoscopy on 3rd postoperative day, if nerve damage was determined, at each six months. Nerve damage and postop hypocalcemia were accepted transient up to 6th month, permanent after 6th month. Total serum calcium levels were postoperatively measured on 24th and 48th hours, and then monthly. RESULTS: Unilateral and bilateral RLN damage were detected as 4.4% and 2.2% in Group 1; and 8% and 2.67% in Group 2, respectively. The frequency of RLN damage was similar (p=0.62). Postoperative hypocalcemia was significantly higher in Group 1 (p=0.04); hypocalcemia was similar (p=0.149). One patient in Group 1, and 2 patients in Group 2 had f superior laryngeal nerve (SLN) injury. Three patients from each group showed permanent hypocalcemia. One patient in Group 1, and two in Group 2 developed permanent hoarseness. DISCUSSION: RLN injury was similar in both groups, however, temporary hypocalcemia was more frequent in patients undergone thyroidectomy with RLN identification at ITA level. CONCLUSIONS: Devascularization of parathyroid glands may be accused. Future studies are needed. KEY WORDS: Recurrent laryngeal nerve, Thyroidectomy.

Selective parathyroid venous sampling in reoperative parathyroid surgery: A key localization tool when noninvasive tests are unrevealing.

BACKGROUND: Preoperative localization studies are essential for parathyroid re-exploration. When noninvasive studies do not regionalize the abnormal parathyroid gland, selective parathyroid venous sampling may be employed. We studied the utility of parathyroid venous sampling in reoperative parathyroid surgery and the factors that may affect parathyroid venous sampling results. METHODS: Patients with hyperparathyroidism and previous cervical surgery undergoing evaluation for reoperative parathyroidectomy over a 20-year period were identified. Patients with indeterminate or negative noninvasive studies underwent parathyroid venous sampling. Parathyroid hormone values were mapped with a ≥2-fold increase above peripheral signifying positive parathyroid venous sampling. These results were correlated with reoperative findings. RESULTS: Parathyroid venous sampling was positive in 113 of 140 (81%). Re-exploration occurred in 75 (66%). Parathyroid venous sampling correctly detected the region of abnormal glands in 58 (77%). With 1 gradient, 1 abnormal gland was found in 81%. With multiple gradients, 1 abnormal gland was found in 78%, most often at the site with the largest gradient. Eighty percent of patients who underwent reoperative parathyroidectomy were biochemically cured. CONCLUSION: Parathyroid venous sampling can guide parathyroid re-exploration when noninvasive localizing studies are indeterminate. Expectation of 1 versus multiple remaining glands was key in interpreting the results.

Effects of active localization and vascular preservation of inferior parathyroid glands in central neck dissection for papillary thyroid carcinoma.

BACKGROUND: The purpose of present study is to assess the effects of active localization and vascular preservation of inferior parathyroid glands in central neck dissection (CND) for papillary thyroid carcinoma (PTC). METHODS: A classification of IPGs according to their location and vascular features was developed, and, based on this classification, a CND procedure was designed, and IPGs and their vascular were actively localized and strategically preserved. A total of 197 patients with PTC who underwent a total thyroidectomy and concomitant CND were enrolled. Eighty-nine patients with traditional meticulous fascia dissection were allocated to group A, and 108 patients with active location and vascular preservation of IPGs were allocated to group B. Those with inferior parathyroid glands auto-transplantation in each group were assigned as group At (18) and group Bt (12). Variables including serum intact parathyroid hormone (PTH), total calcium, the incidence of transient, and permanent hypoparathyroidism were studied. RESULTS: Compared with group A, serum intact PTH (P < 0.001) and total calcium levels (P < 0.05) in group B significantly improved on the first postoperative day, and the incidence of transient hypoparathyroidism significantly dropped in group B (P < 0.001). A total of 170 patients in the two groups had complete follow-up data. The incidence of permanent hypoparathyroidism significantly decreased in group B, from 8.8% to 1.0% (P = 0.017). However, there were no significant differences in all variables between group Bt and group At. CONCLUSION: Active location and vascular preservation of inferior parathyroid glands effectively protected the function of IPGs in CND for PTC.

Role of Ca²âº in Inhibiting Ischemia-Induced Apoptosis of Parathyroid Gland Cells in New Zealand White Rabbits.

BACKGROUND Hypoparathyroidism is a common complication after thyroidectomy. Calcium supplementation can relieve these symptoms, but it is not clear whether it can protect the parathyroid glands. This study aimed to verify whether Ca²âº inhibits the apoptosis of parathyroid cells following ischemic injury. MATERIAL AND METHODS A rabbit model of parathyroid gland ischemic injury was established. The blood calcium concentrations were measured by colorimetry. The parathyroid hormone (PTH) levels were measured by enzyme-linked immunosorbent assay (ELISA). The parathyroid tissues were observed by hematoxylin and eosin (H&E) staining and the TdT-mediated dUTP nick-end labeling (TUNEL) assay. Western blotting was used to quantify the levels of the following proteins: caspase-3 and p38 MAP Kinase (p38 MAPK). RESULTS This study demonstrates that apoptosis can be a part of the pathological changes associated with parathyroid ischemic injury. Calcium supplementation inhibited the apoptosis of parathyroid cells following ischemic injury. There were no significant differences among the serum calcium levels from the Sham operation (Sham), the Control group (CG), or the Calcium supplementation group (CSG) after 24 h, 72 h, and 168 h of treatment. PTH levels in the CG were significantly higher than in the CSG at 24 h and 72 h after treatments. The apoptosis rate of parathyroid cells from rabbits in the CSG was significantly lower than that of those from rabbits in the CG at 24 h and 72 h after the treatment. Calcium supplementation inhibited p38 MAPK and caspase-3 expression. CONCLUSIONS This study demonstrates that calcium supplementation inhibited the apoptosis of parathyroid cells following ischemic injury.

Efficacy of indocyanine green fluorescence in predicting parathyroid vascularization during thyroid surgery.

BACKGROUND: We examined the value of indocyanine green (ICG) fluorescence angiography in predicting parathyroid vascularization following thyroid and central compartment surgeries. METHODS: Data were prospectively collected on adult patients undergoing thyroid and/or central compartment surgeries. Outcomes were compared in surgeries performed with and without ICG use. ICG scoring was used to quantify the vascularity of parathyroid glands. RESULTS: One hundred eleven patients were included; 43 (38.7%) patients underwent ICG injections. There was no significant difference in mean parathyroid hormone (PTH) changes at the end of surgery (29.24 vs 23.48 pg/mL, P = .38), symptomatic hypocalcemia (7.9% vs 3.9%, P = .37), or length of stay (1.095 ± 0.22 vs 0.912 ± 0.07 days, P = .51) between surgeries performed with and without ICG. The average vascularization score among individuals undergoing ICG angiography was 2.89 out of a maximum of 8 points. CONCLUSION: Low-flow ICG patterns are not associated with postoperative PTH changes or transient hypocalcemia and may lead to unnecessary parathyroid autotransplantation.

Superior parathyroid blood supply safety in thyroid cancer surgery: A randomized controlled trial.

BACKGROUND: To evaluate the clinical value of a technique protecting blood supply to the superior parathyroid during surgery for thyroid cancer. MATERIALS AND METHODS: The observation group comprised 113 patients admitted to our hospital during the period from January 1, 2016 to December 31, 2016, who were diagnosed with thyroid cancer and treated by surgery using a technique protecting blood supply to the superior parathyroid. The control group comprised 113 patients diagnosed with thyroid cancer who were treated by surgery using the conventional technique. Postoperative parathyroid function damage and blood calcium levels were assessed in both groups. RESULTS: The incidences of hypocalcemia and low parathyroid hormone in the observation and control groups were 10.6% and 31.9%, and 14.2% and 35.4%, respectively. The relative risk (RR) of the control group was increased (RR = 3.009 for control; RR = 2.493 for observation). Univariate logistic regression analysis showed that postoperative temporary hypoparathyroidism was associated with lymph node metastasis, use of the above protective technique, and tumor size [(odds ratio, OR = 1.936, 95%CI 1.029-3.643; P = 0.041), (OR = 0.301, 95%CI 0.156-0.579; P = 0.001) and (OR = 2.022, 95%CI 1.089-3.756; P = 0.026), respectively]. Postoperative temporary hypoparathyroidism was also associated with lymph node dissection (Bilateral vs. No, P = 0.003) and T classification (T3 vs. T1, P = 0.034). Multivariate logistic regression analysis showed that, after including significant independent variables of univariate logistic regression analysis (e.g., lymph node metastasis, lymph node resection, protective technique, tumor size, and T classification), the protective technique was a factor supporting reduced incidence of postoperative temporary hypoparathyroidism (OR = 0.325, 95% CI 0.163-0.648; P = 0.001). CONCLUSION: Application of a technique protecting blood supply to the superior parathyroid during thyroid cancer surgery effectively reduced the incidence of postoperative temporary hypoparathyroidism. However, because of the imbalance in lymph node dissection between the two groups, confounding factors could not be completely eliminated, and matched pair analysis is needed to eliminate these factors.

Prediction of hypocalcemia after total thyroidectomy using indocyanine green angiography of parathyroid glands: A simple quantitative scoring system.

BACKGROUND: Hypocalcemia is one of the most common complications after total thyroidectomy. Recently, indocyanine green (ICG) angiography of the parathyroid glands (PGs) has been suggested as a reliable tool for predicting postoperative hypocalcemia. The aim of our study was to evaluate the performance of a simple quantitative score based on ICG angiography of the PGs (4-ICG score) for predicting postoperative hypocalcemia. METHODS: Thirty nine consecutive patients who underwent total thyroidectomy for multinodular goiter were included. For each patient, the 4-ICG score was calculated, adding the individual viability value of the four PGs. Discrimination and correlation analyses were performed. RESULTS: In 32/39 patients, the four PGs were identified. Patients with postoperative hypocalcemia (n = 6, 19%) had a lower 4-ICG score (2.5 [1.8-3.3] vs. 4.0 [3.0-6.0]; p = 0.003). The 4-ICG score showed good discrimination in terms of predicting postoperative hypocalcemia (AUC = 0.875 (0.710-0.965); p = 0.001) and a good correlation with postoperative parathyroid function. CONCLUSIONS: The 4-ICG score predicts postoperative hypocalcemia and correlates well with postoperative parathyroid function in patients undergoing total thyroidectomy for multinodular goiter.

Feasibility of indocyanine green fluorescence imaging for intraoperative identification of parathyroid glands during thyroid surgery.

BACKGROUND: This study assessed the feasibility of near-infrared fluorescence imaging with indocyanine green (ICG) to identify the parathyroid glands (PGs) intraoperatively and to assess their perfusion after thyroid resection. METHODS: Patients undergoing elective thyroidectomy were enrolled in this prospective study. An intravenous bolus of 7.5 mg ICG was administered twice: the first bolus to identify the PGs before resection of the thyroid and the second to assess vascularization of the PGs after resection. RESULTS: A total of 30 operations in 26 patients were included. In 17 surgeries (56.7%), fluorescence imaging was of added value, especially to confirm the presence of a suspected PG. No intraoperative or postoperative complications occurred because of the use of ICG. CONCLUSION: Near-infrared fluorescence imaging with the use of ICG for intraoperative identification of the PGs and the assessment of its vascularization is feasible and safe and can provide more certainty about the location of the PGs.

[Intraoperative Indocyanine Green Fluorescence to Assure Vital Parathyroids in Thyroid Resections]. / Intraoperative Indocyaningrün-Fluoreszenzbildgebung zur Sicherung vitaler Nebenschilddrüsen bei Schilddrüsenresektionen.

INTRODUCTION: Total thyreoidectomy is associated with high rates of temporary or permanent hypoparathyroidism. During surgery, ICG fluorescence angiography can be used to detect and preserve well vascularised parathyroid glands; this technique has been recently introduced in retrospective and prospective trials as an intraoperative technical support to avoid postoperative hypoparathyroidism. MATERIALS UND METHODS: 27 patients undergoing total thyreoidectomy were prospectively enrolled in our study. The vascularisation of the parathyroid glands was analysed intraoperatively using ICG tissue angiography. 5 mg indocyanine green were intravenously administered. Fluorescence angiography was evaluated in real time using the PinPoint (Novadaq, Canada) imaging system. The study was approved by the local ethics committee. RESULTS: ICG fluorescence angiography was performed uneventfully in all cases. There was no case of postoperative hypoparathyroidism when at least one parathyroid gland with high fluorescence intensity was preserved. In 4 cases, only low fluorescence intensity was detected in the remaining parathyroid glands after completing the resection. All 4 patients received activated vitamin D3 prophylactically. Two of 4 developed symptomatic hypocalcaemia due to temporary hypoparathyroidism. CONCLUSION: Implementation of ICG fluorescence angiography can help in predicting and therefore preventing postoperative hypoparathyreoidism after total thyreoidectomy. If a well vascularised parathyroid gland with high ICG fluorescence intensity can be secured, calcium substitution and postoperative prophylaxis of hypoparathyreoidism may become obsolete in the future.

Selective parathyroid venous sampling in primary hyperparathyroidism: A systematic review and meta-analysis.

OBJECTIVE: Minimally invasive parathyroidectomy requires accurate preoperative localization techniques. There is considerable controversy about the effectiveness of selective parathyroid venous sampling (sPVS) in primary hyperparathyroidism (PHPT) patients. The aim of this meta-analysis is to examine the diagnostic accuracy of sPVS as a preoperative localization modality in PHPT. METHODS: Studies evaluating the diagnostic accuracy of sPVS for PHPT were electronically searched in the PubMed, EMBASE, Web of Science, and Cochrane Controlled Trials Register databases. Two independent authors reviewed the studies, and revised quality assessment of diagnostic accuracy study tool was used for the quality assessment. Study heterogeneity and pooled estimates were calculated. RESULTS: Two hundred and two unique studies were identified. Of those, 12 studies were included in the meta-analysis. Pooled sensitivity, specificity, and positive likelihood ratio (PLR) of sPVS were 74%, 41%, and 1.55, respectively. The area-under-the-receiver operating characteristic curve was 0.684, indicating an average discriminatory ability of sPVS. On comparison between sPVS and noninvasive imaging modalities, sensitivity, PLR, and positive posttest probability were significantly higher in sPVS compared to noninvasive imaging modalities. Interestingly, super-selective venous sampling had the highest sensitivity, accuracy, and positive posttest probability compared to other parathyroid venous sampling techniques. CONCLUSION: This is the first meta-analysis to examine the accuracy of sPVS in PHPT. sPVS had higher pooled sensitivity when compared to noninvasive modalities in revision parathyroid surgery. However, the invasiveness of this technique does not favor its routine use for preoperative localization. Super-selective venous sampling was the most accurate among all other parathyroid venous sampling techniques. Laryngoscope, 2662-2667, 2018.