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

The overtreatment of papillary thyroid microcarcinoma in the community

INTRODUCTION

Total thyroidectomy is the traditional primary approach for papillary thyroid cancer. However, recent evidence supports conservative management for low-risk tumors like papillary thyroid microcarcinomas (PTMCs). This study explores the adoption of these practices in our community, using a cancer database to analyze treatment strategies.

METHODS

A retrospective review of a 1433-patient institutional database identified 258 ​PTMC cases. Outcomes, including 30-day mortality, reoperation rate, postoperative hypocalcemia, and recurrent laryngeal nerve (RLN) injury, were assessed.

RESULTS

Of PTMC patients, 63.4% underwent total thyroidectomy, with higher rates of RLN injury (8.8% vs. 2.3%) and hypocalcemia (12.4% vs. 0.0%) compared to lobectomy. Non-endocrine surgeons had higher postoperative radioactive iodine administration rates (28.6% vs. 6.1%). Subgroup analysis revealed a shift in total thyroidectomy rates based on tumor size and surgery period.

CONCLUSION

Our community favors total thyroidectomy for PTMC, despite associated complications. Enhanced awareness and adherence to PTMC best practice guidelines are warranted.

Impact of Indocyanine Green Angiography on Postoperative Parathyroid Function: A Propensity Score Matching Study

Background: Thyroidectomy constitutes an important portion of endocrine surgery procedures and is associated with various complications such as bleeding, recurrent laryngeal nerve injury, and postoperative hypoparathyroidsm. Effective parathyroid preservation during thyroid surgery is crucial for patient well-being, with current strategies heavily reliant on surgeon experience. Among various methods, Indocyanine Green Angiography (ICGA) offers a promising method for intraoperative assessment of parathyroid gland perfusion. Methods: In a retrospective study, patients undergoing bilateral thyroidectomy from January 2021 to January 2023 were analyzed, excluding those with previous thyroidectomy, parathyroid disease, or chronic kidney disease. The study compared a control group (n = 175) with an ICGA group (n = 120), using propensity score matching for statistical analysis. Matched cohorts included 120 patients in each group. The primary outcome of this study was identified as temporary postoperative hypoparathyroidism, with secondary outcomes including the rate of parathyroid reimplantation and the incidence of permanent postoperative hypoparathyroidism. Results: The ICGA group showed significantly more parathyroid autotransplantations (p < 0.01). While not statistically significant, the control group had a higher incidence of temporary postoperative hypoparathyroidism (p < 0.09). Rates of hypocalcemia on postoperative day 1 and permanent hypocalcemia were similar. Subgroup analysis indicated more postoperative day 1 hypoparathyroidism in the control group during central neck dissections (p < 0.049). Conclusions: Intraoperative ICGA use correlated with higher parathyroid autotransplantation and suggested reduced postoperative hypoparathyroidism. Changes in fluorescence intensity following a second ICG injection may provide an objective method to assess parathyroid perfusion. Further large-scale studies are needed to fully understand ICGA's impact on parathyroid preservation.

Comparison of indocyanine green angiography vs intraoperative parathyroid hormone in early prediction of risk of post-thyroidectomy hypocalcemia: a prospective cohort study

Introduction

Indocyanine green (ICG) angiography is the 'real-time intraoperative imaging' technique used to reduce the chances of hypoparathyroidism in post-thyroidectomy patients. In our study, the authors predicted the risk of early post-thyroidectomy hypocalcemia by intraoperative evaluation of parathyroid gland perfusion by ICG angiography.

Materials and methods

In patients who underwent total thyroidectomy, ICG angiography was done using the SPY PHI imaging system (Stryker). Post-thyroid specimen removal, scoring of parathyroids was done in spy contrast mode. All 4 or <4 visualized parathyroids were scored for vascularity with the highest score of 8. Serum ionized calcium was done 6 h postsurgery and on the morning and evening of postoperative days 1 and 2. Calcium supplements were given to only those who developed clinical or severe biochemical hypocalcemia.

Results

Out of 60, postoperative hypocalcemia was noted in 41 patients. Total ICG score ≤5 was seen in 34 patients, out of which 28 developed postoperative hypocalcemia showing PPV 82.3% and diagnostic accuracy of 68.3% while iPTH (4.28 pmol/l) showed PPV 76.7 and diagnostic accuracy 70 %. In eight patients, none of the glands was scored as 2 (White) and all these patients developed hypocalcemia requiring calcium infusion.

Conclusion

The absence of visualization of at least 1 well-perfused (score 2) gland on ICG angiography is highly predictive of hypocalcemia and the majority of patients with total ICG score ≤5 developed hypocalcemia in the immediate postoperative period. ICG is a good predictor of the absence of hypoparathyroidism after thyroidectomy and is comparable to iPTH in the prediction of post-thyroidectomy hypocalcemia.

Avoiding Complications of Thyroidectomy: Preservation of Parathyroid Glands

Preservation of functional parathyroid glands during thyroidectomy and central neck surgery is crucial to avoid the common but serious complication of hypoparathyroidism. The first requirement is a solid foundational knowledge of anatomy and embryology which then enables the surgeon to use meticulous anticipatory dissection with identification and preservation of blood supply to the parathyroids. When preservation of blood supply is not possible, autotransplantation should be performed. New technologies harnessing the natural phenomenon of parathyroid autofluorescence to detect parathyroid tissue and indocyanine green to perform angiography may lead to improved outcomes with low risk to patients.

Assessing Parathyroid Gland Viability and Predicting Postoperative Hypoparathyroidism in Thyroid Surgery: The Utility of Indocyanine Green Angiography

Objectives

Postoperative hypoparathyroidism is a common complication following thyroidectomy, with the potential for significant morbidity and cost. While various techniques have been proposed for intraoperative parathyroid gland (PG) identification and preservation, indocyanine green (ICG) angiography has emerged as a promising method. In this retrospective study, patients who underwent total thyroidectomy with or without central neck dissection were evaluated for the utility of ICG angiography in identifying PGs and the correlation of ICG scores with postoperative parathyroid function.

Methods

ICG angiography was performed using a standardized protocol, and the degree of PG vascularization was assessed visually. A scoring system was employed based on ICG uptake intensity in PGs, as described in the literature. Pearson's correlation test examined the relationship between the total ICG score and percentage parathyroid hormone (PTH) gradient, postoperative calcium, and PTH levels. In addition, patients with at least one well-vascularized PG were also evaluated.

Results

Twenty-two patients were included in the study. Significant positive correlations were found between the total ICG score and postoperative PTH levels (r=0.549, p=0.008), and a negative correlation with the percentage of PTH gradient (r=-0.504, p=0.01). However, six patients with well-vascularized PGs on ICG angiography still developed postoperative hypoparathyroidism.

Conclusion

ICG angiography offers a potential tool for evaluating PG vascularization during thyroidectomy and predicting the risk of postoperative hypoparathyroidism. However, its application should be used judiciously, and the technique should be improved for PG preservation. Further studies are warranted to better understand its benefits and limitations in thyroid surgery.

Intraoperative prevention of postoperative hypoparathyroidism

Objective

More than 30,000 thyroid surgeries are performed annually in the Russian Federation. The surgeries are relatively safe because of the prevention methods for postoperative complications. Currently, there is no single effective method of postoperative hypoparathyroidism prevention. This complication is frequently reported and may be health and life-threatening.

Aim

We aimed to estimate the effectiveness of the intraoperative ICG-angiography and intrathyroid injection of Brilliant Green for the prevention of postoperative hypoparathyroidism.

Material and methods

One hundred and forty-three thyroidectomies were performed. Patients were divided into three groups: intraoperative angiography was used in 24 cases; Brilliant Green was injected in 58 cases to identify parathyroid glands; the visual estimation of the parathyroid preservation was used in 61 cases. Calcium level was measured in all patients before and after surgery.

Results

Calcium level in the serum before and after surgery was 2.37±0.14 and 2.27±0.17 in Group 1, 2.38±0.16 and 2.21±0.16 in Group 2, and 2.39±0.17 and 2.18±0.19 in Group 3. Postoperative hypocalcemia was more prominent in the group with the visually estimated PTG than in the two other groups. The differences in postoperative calcium levels in Groups 1 and 3 were statistically different. Pre- and postoperative Parathormone levels were 6.2±0.4 in Group 1, 5.6±0.57 in Group 2, and 3.5±0.32 in Group 3. Postoperative levels significantly differed in Groups 1 and 3 (p<0.01) and in Groups 2 and 3 (p<0.05).

Conclusions

ICG-angiography and intrathyroid injection of the Brilliant Green are safe methods of identification and sparing of the parathyroid glands. The severity of hypocalcemia and hypoparathormonemia in Group 3 shows the necessity of finding new methods in endocrine surgery to improve patient outcomes.

Comparing laser speckle contrast imaging and indocyanine green angiography for assessment of parathyroid perfusion

Accurate intraoperative assessment of parathyroid blood flow is crucial to preserve function postoperatively. Indocyanine green (ICG) angiography has been successfully employed, however its conventional application has limitations. A label-free method overcomes these limitations, and laser speckle contrast imaging (LSCI) is one such method that can accurately detect and quantify differences in parathyroid perfusion. In this study, twenty-one patients undergoing thyroidectomy or parathyroidectomy were recruited to compare LSCI and ICG fluorescence intraoperatively. An experimental imaging device was used to image a total of 37 parathyroid glands. Scores of 0, 1 or 2 were assigned for ICG fluorescence by three observers based on perceived intensity: 0 for little to no fluorescence, 1 for moderate or patchy fluorescence, and 2 for strong fluorescence. Speckle contrast values were grouped according to these scores. Analyses of variance were performed to detect significant differences between groups. Lastly, ICG fluorescence intensity was calculated for each parathyroid gland and compared with speckle contrast in a linear regression. Results showed significant differences in speckle contrast between groups such that parathyroids with ICG score 0 had higher speckle contrast than those assigned ICG score 1, which in turn had higher speckle contrast than those assigned ICG score 2. This was further supported by a correlation coefficient of -0.81 between mean-normalized ICG fluorescence intensity and speckle contrast. This suggests that ICG angiography and LSCI detect similar differences in blood flow to parathyroid glands. Laser speckle contrast imaging shows promise as a label-free alternative that overcomes current limitations of ICG angiography for parathyroid assessment.

Quantification of Indocyanine Green Fluorescence Imaging in General, Visceral and Transplant Surgery

Near-infrared (NIR) imaging with indocyanine green (ICG) has proven to be useful in general, visceral, and transplant surgery. However, most studies have performed only qualitative assessments. Therefore, a systematic overview of all studies performing quantitative indocyanine green evaluation in general, visceral, and transplant surgeries should be conducted. Free term and medical subject heading (MeSH) term searches were performed in the Medline and Cochrane databases until October 2022. The main categories of ICG quantification were esophageal surgery (24.6%), reconstructive surgery (24.6%), and colorectal surgery (21.3%). Concordantly, anastomotic leak (41%) was the main endpoint, followed by the assessment of flap perfusion (23%) and the identification of structures and organs (14.8%). Most studies examined open surgery (67.6%) or laparoscopic surgery (23.1%). The analysis was mainly carried out using manufacturer software (44.3%) and open-source software (15.6%). The most frequently analyzed parameter was intensity over time for blood flow assessment, followed by intensity alone or intensity-to-background ratios for structure and organ identification. Intraoperative ICG quantification could become more important with the increasing impact of robotic surgery and machine learning algorithms for image and video analysis.

Indocyanine green angiography-guided thyroidectomy versus conventional thyroidectomy for preserving parathyroid function: study protocol for a randomized single-blind controlled trial

Introduction

Angiography with indocyanine green (ICG) fluorescence performed before thyroidectomy would allow identification of the vascularization of parathyroid glands, maximizing efforts for preserving functioning glands intraoperatively. The rationale of the study was based on the hypothesis that showing the vascular pattern of the parathyroid glands by means of ICG angiography before performing the thyroidectomy could prevent permanent hypoparathyroidism.

Methods and analysis

We propose a randomized single-blind controlled and multicenter clinical trial to assess the efficacy and safety of ICG angiography-guided thyroidectomy to identify the vascular pattern of the parathyroid glands versus conventional thyroidectomy in patients scheduled for elective total thyroidectomy. Patients will be randomized 1:1 to ICG angiography-guided thyroidectomy (experimental group) or conventional thyroidectomy (control group). Patients in the experimental group will undergo ICG angiography before thyroidectomy to identify the feeding vessels of the parathyroid glands and then, post-thyroidectomy ICG angiography to predict immediate parathyroid gland function by scoring the degree of fluorescence of the glands. Patients in the control group will undergo post-thyroidectomy ICG angiography only. The primary outcome measure will be the rate of patients with permanent hypoparathyroidism. Secondary outcome measures will be rate of postoperative hypoparathyroidism, the percentage of well vascularized parathyroid glands remaining in situ, the levels of iPTH and serum calcium after surgery and the influence of the type of vascular pattern of the parathyroid glands over these outcomes, as well as the safety profile of ICG angiography.

Discussion

The results will contribute to adopt a new surgical strategy based on intraoperative ICG angiography before performing total thyroidectomy, according to which the rate of permanent hypoparathyroidism could be substantially reduced.

Clinical trial registration

ClinicalTrials.gov. identifier NCT05573828.

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.

Safe thyroid surgery: comparison effectiveness of ICG angiography and intrathyroidal brilliant green injection for the prevention of postoperative hypoparathyroidism

BACKGROUND: More than 30,000 surgical interventions on the thyroid gland are performed annually in the Russian Federation. Surgeons are developing methods for the prevention of various postoperative complications, and therefore operations on this organ are considered relatively safe. Currently, there is no unequivocal effective method to prevent postoperative hypoparathyroidism. This complication is often recorded and can threaten the life and health of the patient, which is contrary to the concept of safe surgery.

AIM: To evaluate the effectiveness of intraoperative ICG angiography and intrathyroidal injection of brilliant green for the prevention of postoperative hypoparathyroidism.

MATERIALS AND METHODS: 143 thyroidectomies were performed. The patients were divided into 3 groups: intraoperative angiography was used in 24 cases, brilliant green was injected to identify the parathyroid glands in 58 cases, visual assessment of the preservation of the parathyroid glands was used in 61 case. Calcium levels were measured in all patients included in the study before and after surgery.

RESULTS: Serum calcium levels in the pre- and postoperative period: 2.37±0.14 and 2.27±0.17 in group 1, and 2.38±0.16 and 2.21±0.16 in group 2, 2.39±0.17 and 2.18±0.19 in group 3. Hypocalcemia in the postoperative period was significantly higher in the group with a visual assessment of the parathyroid glands relative to the first two groups. Differences between calcium levels in the postoperative period in groups 2 and 3 were significant with a probability of more than 99% (p<0.01). Significant differences (≥95%) in calcium levels in the postoperative period between groups 1 and 2 (p < 0.05) were obtained. Serum PTH levels in the postoperative period: 6,2±0,4 in group 1, 5,6±0,57 in group 2, 3,5±0,32 in group 3. Differences between PTH levels in the postoperative period in groups 1 and 3 were significant with a probability of more than 99% (p<0.01). Significant differences (≥95%) in PTH levels in the postoperative period between groups 2 and 3 (p < 0.05) were obtained.

CONCLUSION: ICG angiography and brilliant green intrathyroidal injection are safe methods for identifying and preserving the parathyroid glands. The high level of hypocalcemia in group 3 indicates the need to search for new techniques in endocrine surgery in order to improve the safety of patients undergoing surgical treatment of thyroid pathology.

Near-infrared fluorescent imaging techniques for the detection and preservation of parathyroid glands during endocrine surgery

Objectives

In over 30% of all thyroid surgeries, complications arise from transient and definitive hypoparathyroidism, underscoring the need for real-time identification and preservation of parathyroid glands (PGs). Here, we evaluate the promising intraoperative optical technologies available for the identification, preservation, and functional assessment of PGs to enhance endocrine surgery.

Methods

We performed a review of the literature to identify published studies on fluorescence imaging in thyroid and parathyroid surgery.

Results

Fluorescence imaging is a well-demonstrated approach for both in vivo and in vitro localization of specific cells or tissues, and is gaining popularity as a technique to detect PGs during endocrine surgery. Autofluorescence (AF) imaging and indocyanine green (ICG) angiography are two emerging optical techniques to improve outcomes in thyroid and parathyroid surgeries. Near-infrared-guided technology has significantly contributed to the localization of PGs, through the detection of glandular AF. Perfusion through the PGs can be visualized with ICG, which can also reveal the blood supply after dissection.

Conclusions

Near infrared AF and ICG angiography, providing a valuable spatial and anatomical information, can decrease the incidence of complications in thyroid surgery.

Assessing the development status of intraoperative fluorescence imaging for anatomy visualisation, using the IDEAL framework

Objectives

Intraoperative fluorescence imaging is currently used in a variety of surgical fields for four main purposes: visualising anatomy, assessing tissue perfusion, identifying/localising cancer and mapping lymphatic systems. To establish evidence-based guidance for research and practice, understanding the state of research on fluorescence imaging in different surgical fields is needed. We evaluated the evidence on fluorescence imaging used to visualise anatomical structures using the IDEAL framework, a framework designed to describe the stages of innovation in surgery and other interventional procedures.

Design

IDEAL staging based on a thorough literature review.

Setting

All publications on intraoperative fluorescence imaging for visualising anatomical structures reported in PubMed through 2020 were identified for five surgical procedures: cholangiography, hepatic segmentation, lung segmentation, ureterography and parathyroid identification.

Main outcome measures

The IDEAL stage of research evidence was determined for each of the five procedures using a previously described approach.

Results

225 articles (8427 cases) were selected for analysis. Current status of research evidence on fluorescence imaging was rated IDEAL stage 2a for ureterography and lung segmentation, IDEAL 2b for hepatic segmentation and IDEAL stage 3 for cholangiography and parathyroid identification. Enhanced tissue identification rates using fluorescence imaging relative to conventional white-light imaging have been documented for all five procedures by comparative studies including randomised controlled trials for cholangiography and parathyroid identification. Advantages of anatomy visualisation with fluorescence imaging for improving short-term and long-term postoperative outcomes also were demonstrated, especially for hepatobiliary surgery and (para)thyroidectomy. No adverse reactions associated with fluorescent agents were reported.

Conclusions

Intraoperative fluorescence imaging can be used safely to enhance the identification of anatomical structures, which may lead to improved postoperative outcomes. Overviewing current research knowledge using the IDEAL framework aids in designing further studies to develop fluorescence imaging techniques into an essential intraoperative navigation tool in each surgical field.

Indocyanine Green Angiography of Parathyroid Glands versus Intraoperative Parathyroid Hormone Assay as a Reliable Predictor for Post Thyroidectomy Transient Hypocalcemia

BACKGROUND

Prediction of postoperative hypocalcemia is a fundamental issue in thyroidectomy. Indocyanine green (ICG) angiography of parathyroid glands is a feasible method to detect the perfusion of parathyroid glands and predict postoperative hypocalcemia.

MATERIALS AND METHODS

A prospective observational study was conducted at Ain Shams University Hospitals between April 2018 and April 2021. The included cases of total thyroidectomy underwent intraoperative ICG fluorescence angiography to identify the four parathyroid glands and score each gland according to the viability. Patients in which less than four glands were identified were excluded. Intraoperative intact parathyroid hormone (ioPTH) level assay was also measured to compare with ICG in predicting postoperative transient hypocalcemia.

RESULTS

A total of 134 cases underwent total thyroidectomy during the study period. We could identify the four parathyroid glands in 90 patients, including them in the study. We had postoperative hypocalcemia in 28 cases (31.1%). The diagnostic accuracy of ICG angiography and ioPTH level assay was high and almost similar (82.22% versus 87.78%). Both were higher than the surgeons' diagnostic accuracy of visual inspection (62.22%).

CONCLUSIONS

ICG angiography of the parathyroid gland is a safe, reliable predictor for postoperative transient hypocalcemia with a high and almost similar accuracy compared to intraoperative parathyroid hormone level.

Heterogeneity in Utilization of Optical Imaging Guided Surgery for Identifying or Preserving the Parathyroid Glands—A Meta-Narrative Review

Background: Postoperative hypoparathyroidism is the most common complication after total thyroidectomy. Over the past years, optical imaging techniques, such as parathyroid autofluorescence, indocyanine green (ICG) angiography, and laser speckle contrast imaging (LSCI) have been employed to save parathyroid glands during thyroid surgery. This study provides an overview of the utilized methods of the optical imaging techniques during total thyroidectomy for parathyroid gland identification and preservation. Methods: PUBMED, EMBASE and Web of Science were searched for studies written in the English language utilizing parathyroid autofluorescence, ICG-angiography, or LSCI during total thyroidectomy to support parathyroid gland identification or preservation. Case reports, reviews, meta-analyses, animal studies, and post-mortem studies were excluded after the title and abstract screening. The data of the studies were analyzed qualitatively, with a focus on the methodologies employed. Results: In total, 59 articles were included with a total of 6190 patients. Overall, 38 studies reported using parathyroid autofluorescence, 24 using ICG-angiography, and 2 using LSCI. The heterogeneity between the utilized methodology in the studies was large, and in particular, regarding study protocols, imaging techniques, and the standardization of the imaging protocol. Conclusion: The diverse application of optical imaging techniques and a lack of standardization and quantification leads to heterogeneous conclusions regarding their clinical value. Worldwide consensus on imaging protocols is needed to establish the clinical utility of these techniques for parathyroid gland identification and preservation.

Application of Indocyanine Green Angiography in Bilateral Axillo-Breast Approach Robotic Thyroidectomy for Papillary Thyroid Cancer

BACKGROUND

Indocyanine green angiography (ICGA) has been used to identify and preserve the parathyroid glands (PGs), and to evaluate PGs viability and function during thyroid surgery. However, evidence on the utilization of IGCA in thyroid cancer and robotic surgery is lacking. The efficacy of IGCA remains to be evaluated in PTC patients undergoing bilateral axillo-breast approach robotic thyroidectomy (BABA RT) and central neck dissection (CND).

METHODS

From March 2020 to August 2021, 81 papillary thyroid cancer (PTC) patients receiving total thyroidectomy and CND were enrolled in this retrospective analysis. An intravenous bolus of 7.5 mg ICG was administrated three times in the ICGA group (n=34). Medical records were reviewed and analyzed, including the baseline characteristics, surgical parameters, PGs-related parameters, and perioperative PTH and calcium levels.

RESULTS

The mean number of total identified PGs and preserved PGs were significantly more in the ICG group than in the control group (3.74 ± 0.45 vs. 3.15 ± 0.55, P<0.001; 3.12 ± 0.64 vs. 2.74 ± 0.57, P=0.007, respectively), as were PTH and calcium levels on POD 1 (23.16 ± 18.32 vs. 6.06 ± 7.74, P=0.039; 2.13 ± 0.11 vs. 2.08 ± 0.08, P=0.024, respectively). While there were no differences in PTH levels on POD 30. Additionally, patients with at least one well vascularized PG had higher ioPTH 3 and PTH on POD 1, which significantly suggested the absence of postoperative hypocalcemia. Although not statistically significant, ICGA seemed superior to relative ioPTH decline and ioPTH 3 in predicting postoperative hypocalcemia.

CONCLUSION

In PTC patients undergoing BABA RT and CND, ICGA is a simple, safe, effective, and cost-effective tool in better identification and preservation of PGs as well as evaluation of PGs viability and function, with the potential to preserve more PGs, guide more appropriate autotransplantation, and accurately predict postoperative hypocalcemia.

Indocyanine green fluorescence for parathyroid gland identification and function prediction: Systematic review and meta-analysis

BACKGROUND

To evaluate the diagnostic accuracies of indocyanine green (ICG) fluorescence for identifying parathyroid glands during surgery and predicting the postoperative function.

METHODS

From six databases, 21 studies were finally included in the study. True-positive, true-negative, false-positive, and false-negative data were extracted for the analysis. The quality of each study was analyzed using the QUADAS-2 tool.

RESULTS

The sensitivity of ICG-based parathyroid gland identification was 0.9380 (95% CI [0.9003, 0.9621]). The diagnostic odds ratio for ICG-based prediction of parathyroid gland function was 54.5652 [13.2059, 225.4570]. The area under the summary receiver operating characteristic curve was 0.909. Fluorescence intensity-based prediction presented higher diagnostic accuracy than that of score-based prediction. The incidence of postoperative hypoparathyroidism was higher in the group with a zero ICG score compared to the high scored group.

CONCLUSIONS

Identification of parathyroid gland and prediction of postoperative function using ICG are valuable to patients undergoing thyroidectomy or parathyroidectomy.

The utility of indocyanine green (ICG) for the identification and assessment of viability of the parathyroid glands during thyroidectomy

We conducted this study to evaluate the ability of indocyanine green (ICG) and near infra-red fluorescence (NIRF) camera to aid in the identification and assessment of viability of parathyroid glands during thyroid surgery. A prospective observational study was conducted between May and October 2020 among 50 consecutive patients who underwent total thyroidectomy at a single institution. Parathyroid glands were identified under white light during thyroidectomy following which reconstituted ICG was injected through a peripheral vein and the location of parathyroid glands was confirmed. The perfusion to the parathyroid gland was assessed by documenting the fluorescence intensity score (FIS) and the parathyroid angiogram score (PAS). There was no difference in the number of parathyroid glands seen on visual inspection 147 (73.5%) when compared to under NIRF camera, 146 (73%). Though the rate of postoperative hypoparathyroidism was lower in the cohort with FIS 3 (14.2%) compared to score 2 and 1 (28.5% and 100%, respectively), this was not significant (p = 0.35). A significant correlation was noted between a delayed flow on PAS and the development of post-thyroidectomy hypoparathyroidism (p = 0.01). PAS had a sensitivity of 100%, specificity of 88.6%, NPV of 100% and PPV of 55.6% to predict the development of post-thyroidectomy hypoparathyroidism. In this study, there was no additional benefit of ICG and NIRF camera in the identification of parathyroid glands. However, ICG angiogram seems to be a good adjunct for the intraoperative assessment of the viability of the parathyroid glands and accurately predicts the development of postoperative hypoparathyroidism.

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.

Intraoperative Indocyanine Green Angiography of Parathyroid Glands and the Prevention of Post-Thyroidectomy Hypocalcemia

BACKGROUND

We compared the reliability of indocyanine green (ICG) angiography and intraoperative PTH levels for predicting early post-thyroidectomy hypocalcemia.

METHODS

Prospective study of 94 patients (71% women, mean age 53.7 years) undergoing total thyroidectomy. An ICG score of 2 (white) indicated a well-vascularized gland. PTH preoperative levels-PTH postresection levels divided by preoperative PTH × 100 was used to determine the PTH decline percentage. A decrease of at least 62.5% or <17.1 pg/mL in ioPTH was the criterion for predicting hypocalcemia.

RESULTS

At surgery, the four parathyroid glands were identified in 50 (53.2%) patients and <4 glands in 44. Calcium supplements were needed by 22 patients (23.4%) postoperatively, 11 patients in each group of 4 and <4 parathyroid glands identified. The diagnostic accuracy of ICG angiography (0.883, 95% confidence interval [CI] 0.800-0.940) and ioPTH (0.862, 95% CI 0.775-0.92) was similar. When all four parathyroid glands were identified, ICG angiography showed a slightly higher diagnostic accuracy, specificity and positive predictive than ioPTH levels, but when < 4 glands were identified, the ioPTH showed a slightly higher diagnostic accuracy, specificity and positive predictive value. Differences were not statistically significant for any of the comparisons.

CONCLUSIONS

The presence of one well-perfused parathyroid gland (ICG score 2) using ICG angiography or ioPTH decline, measured before and after completion of thyroid surgery, is both reliable methods in prediction of early post-thyroidectomy hypocalcemia independently of the number of glands identified intraoperatively.

Intraoperative indocyanine green (ICG) angiography of the parathyroids glands in prediction of post-thyroidectomy hypocalcemia: Diagnostic accuracy of the ICG score 2 versus the 4-ICG score

INTRODUCTION

Indocyanine green (ICG) angiography of the parathyroids is useful in prediction of postthyroidectomy hypocalcemia. We compared the diagnostic accuracy of a single-gland ICG score of 2 with a score estimated by adding the viability value of the four glands (4-ICG).

METHODS

Fifty patients (66% women, median age 49.4 years) underwent total thyroidectomy with identification of all 4 glands. The degree of ICG was classified as 0, black (nonvascularized), 1, gray/heterogeneous (partially vascularized), and 2, white (well vascularized).

RESULTS

The diagnostic accuracy of the optimal cut-off of the 4-ICG sum score ≤3 was 84% (95% CI 70.9-92.8) lower than the diagnostic accuracy of 92% (80.8-97.8) of the ICG score 2. Both scores identified 2 false negative cases, but the rates of false positives were lower with the ICG score 2 (18.2% vs. 57.1%).

CONCLUSIONS

Identification of single-gland ICG score of 2 has a higher diagnostic accuracy than 4-ICG sum score to predict immediate hypocalcemia after total thyroidectomy.

Intraoperative indocyanine green (ICG) angiography of the parathyroids glands in prediction of post-thyroidectomy hypocalcemia: Diagnostic accuracy of the ICG score 2 versus the 4-ICG score

INTRODUCTION

Indocyanine green (ICG) angiography of the parathyroids is useful in prediction of postthyroidectomy hypocalcemia. We compared the diagnostic accuracy of a single-gland ICG score of 2 with a score estimated by adding the viability value of the four glands (4-ICG).

METHODS

Fifty patients (66% women, median age 49.4 years) underwent total thyroidectomy with identification of all 4 glands. The degree of ICG was classified as 0: black (nonvascularized), 1: gray/heterogeneous (partially vascularized), and 2: white (well vascularized).

RESULTS

The diagnostic accuracy of the optimal cut-off of the 4-ICG sum score ≤3 was 84% (95% CI: 70.9-92.8) lower than the diagnostic accuracy of 92% (80.8-97.8) of the ICG score 2. Both scores identified 2 false negative cases, but the rates of false positives were lower with the ICG score 2 (18.2 vs. 57.1%).

CONCLUSIONS

Identification of single-gland ICG score of 2 has a higher diagnostic accuracy than 4-ICG sum score to predict immediate hypocalcemia after total thyroidectomy.

Higher prevalence of Concomitant Hyperparathyroidism in African American Patients Undergoing Thyroid Surgery

BACKGROUND

Hyperparathyroidism (HPT) occurs in about 1% of the general population. Previous studies have suggested that the incidence is higher in those patients with thyroid disease who are undergoing thyroid surgery. The study purpose was to examine the incidence of concomitant HPT in patients already undergoing a thyroid procedure and to identify risk factors.

MATERIALS AND METHODS

A prospective database of all patients who had thyroidectomy by the endocrine surgery team was reviewed between August 2012 and April 2020. Per institutional protocol, all patients having thyroid surgery were screened for concomitant hyperparathyroidism. ANOVA/T-Test and Chi-square were conducted to compare those with and without hyperparathyroidism.

RESULTS

The median age was 43 and 79% were female. Of the 481 patients undergoing thyroidectomy, 31 (6%) had HPT. The mean preoperative calcium and parathyroid hormone levels were 10 ± 0 mg/dL and 67 ± 5 pg/mL, respectively. When comparing the groups, patients with concomitant HPT were older (53 ± 4 versus 42 ± 1 y, P = 0.005). African American race was a significant risk factor for concomitant HPT. While African Americans represented only 29% of those undergoing surgery, 58% of those with concomitant HPT were African American (P = 0.007).

CONCLUSION

In patients having thyroid surgery, concomitant HPT was present in 6% of the population, higher than estimated general population prevalence. While we understand that primary HPT incidence increases with age, to our knowledge, this is the first report to document that African Americans are at a higher risk for concomitant HPT with thyroid disease. Thus, routine screening for hyperparathyroidism in patients undergoing thyroid surgery, especially in vulnerable populations, such as the older and African American population, is beneficial.

Impact of outcomes data on the management of postoperative hypocalcemia in head and neck endocrine surgery patients

Postoperative hypocalcemia is a well-described outcome following thyroid and parathyroid surgery with symptoms ranging from clinically insignificant laboratory findings to tetany and seizures. The aims of this study were 1. To identify the characteristics and management patterns of postoperative hypocalcemia in head and neck endocrine surgery patients and 2. To compare outcomes between patients treated with empiric calcium and patients treated using a biochemically driven calcium replacement algorithm. Clinical electronic medical record (EMR) data was collected from patients who had undergone total thyroidectomy, completion thyroidectomy, and/or parathyroidectomy at Wake Forest Baptist Medical Center (WFBMC), a tertiary referral and academic institution. Between July 1, 2016, and June 30, 2017, 298 adult patients underwent surgery by a WFBMC Head & Neck (H&N) endocrine surgeon. Objective calcium and parathyroid hormone levels, postoperative supplementation with calcium and Vitamin D, 30-day physician access line (PAL) phone call utilization, emergency department (ED) encounters, and readmission rates were queried. The overall rate of hypocalcemia was 17.4%. No statistically significant difference in PAL utilization, ED visits, or readmissions was found between the empiric supplementation group and those whose supplementation was biochemically directed (PAL 5.0% vs. 5.0% [p = 0.983], ED visit 3.3% vs. 2.5% [p = 0.744], Readmission 1.7% vs. 0% [p = 0.276]). The overall postoperative rates of hypocalcemia and hypoparathyroidism following H&N endocrine surgery were consistent with the reported literature. Neither method of calcium supplementation was superior in reducing PAL utilization, ED encounters, or readmission.

Intraoperative Autofluorescence and Indocyanine Green Angiography for the Detection and Preservation of Parathyroid Glands

Fluorescence imaging is a well-known method for both the in vivo and in vitro identification of specific cells or tissues. This imaging tool is gaining importance in the intraoperative detection and preservation of parathyroid glands during endocrine surgery owing to the intrinsic properties of parathyroid tissue. The aim of this paper is to provide an overview of the basics of the technology, its history, and the recent surgical intraoperative applications of near-infrared imaging methods. Moreover, a literature review of the utilization of fluorescence devices in thyroid surgery suggests that the use of near-infrared imaging seems to be beneficial in reducing postoperative hypoparathyroidism, which is one of the most frequent complications of thyroid surgery.