Preservation of parathyroid glands during thyroid and neck surgery

Impact of parathyroid gland classification on hypoparathyroidism following total thyroidectomy with central neck dissection for differentiated thyroid cancer

OBJECTIVE

To assess the impact of parathyroid gland (PG) classification on hypoparathyroidism incidence following total thyroidectomy (TT) with central neck dissection (CND) in patients with differentiated thyroid carcinoma (DTC).

METHODS

In this prospective cohort study, adult patients with DTC who underwent TT with CND between 2021 and 2023 were enrolled, with a maximum follow-up duration of 32 months. A simplified PG classification system was employed, categorizing glands into four distinct types: tightly connected, loosely connected, non-connected, and thymic. The intraoperative frequency of each PG type was recorded based on this classification. Parathyroid hormone (PTH) levels were routinely tested 1 day, 1 month, 6 months and 1 year after surgery. The association between PG classification and the incidence of postoperative hypoparathyroidism was then systematically analysed.

RESULTS

Among 135 patients with DTC (mean age: 48.50 ± 10.52 years; 101 women), 62 patients (45.93%) developed hypoparathyroidism on postoperative day 1 (POD1), while 14 patients (10.37%) experienced hypoparathyroidism on postoperative month 1 (POM1). All patients exhibited PTH normalization within six months, with no permanent hypoparathyroidism cases. A total of 532 PGs were identified: 264 (49.62%) were tightly connected, 150 (28.20%) loosely connected, 95 (17.86%) non-connected, and 23 (4.32%) thymic. The highest prevalence of hypoparathyroidism on POD1 was observed in patients with four tightly connected PGs (p < 0.001). Patients with four tightly connected PGs had a significantly greater incidence of hypoparathyroidism than those with none (p = 0.024). Regression analysis revealed that each additional tightly connected PG increased the risk of hypoparathyroidism by 1.38 times (p = 0.019). Tightly connected PGs demonstrated predictive value for POD1 hypoparathyroidism (AUC = 0.604, cut-off: two tightly connected glands). In contrast, thymic PGs did not provide a protective effect.

CONCLUSION

PG classification may serve as a valuable tool for surgeons in intraoperative parathyroid preservation and the prediction of postoperative hypoparathyroidism in patients with DTC. Notably, DTC patients with more than two tightly connected PGs are at an elevated risk of developing temporary hypoparathyroidism, emphasizing the importance of meticulous parathyroid preservation during surgical procedures.

Comparison of short-term outcomes following minimally invasive (endoscopic/robotic) vs open thyroidectomy for patients with thyroid cancer

Background

Selection between open thyroidectomy (OT) and minimally invasive (endoscopic/robotic) thyroidectomy for patients with thyroid cancer has been a subject of considerable debate. Comprehensive analysis of the short-term outcomes of endoscopic thyroidectomy (ET), robotic-assisted thyroidectomy (RT) and open thyroidectomy (OT) for thyroid cancer using a large-scale dataset is important.

Methods

This cohort study evaluated the outcomes of patients receiving ET, RT or OT for thyroid cancer from January 1, 2003, to December 31, 2022. Propensity score matching (PSM) was performed among patients treated with ET, RT or OT to balance covariates distribution. This study involved single-institution patients (aged 18-70) who had undergone ET, RT or OT for thyroid cancer.

Results

The study included 11,066 thyroid cancer patients (OT group- mean (SD) age: 42.45 (10.84) years; ET group- mean (SD) age: 36.75 (9.32) years and RT group- mean (SD) age: 40.27 (10.42) years). After PSM for demographic and clinical characteristics, 908 matched pairs of patients (ET vs OT) and 1480 matched pairs (RT vs OT) were included for further analysis. Complication analysis revealed that RT was associated with a lower rate of transient hypoparathyroidism (339 (22.9%) vs 687 (46.4%); P < 0.001), a lower rate of permanent hypoparathyroidism (4 (0.3%) vs 16 (1.1%); P = 0.012) and a lower rate of transient recurrent laryngeal nerve injury (63 (4.3%) vs 89 (6.0%); P = 0.037).

Conclusion

This cohort study analyzed the short-term outcomes between ET, RT and OT in a large sample of patients with thyroid cancer over a period of two decades. PSM provided a comparable cohort, and the results suggested the advantage of RT, which reduced Clavien-Dindo grade Ⅰ complications in the surgical treatment of thyroid cancer.

Intraoperative parathyroid gland recognition prediction model and key feature analysis based on white light images

Background

Timely identification and protection of the parathyroid glands during thyroid surgery are important. This study aims to explore a convenient, efficient, and inexpensive method for identifying parathyroid glands during surgery by extracting subtle texture features that cannot be recognized by the naked eye from white light images.

Methods

In total, 117 confirmed parathyroid gland photos and 169 oval tissue photos of non-parathyroid glands, such as suspected parathyroid gland fat granules and lymph nodes, were collected. All the photos were subjected to color channel conversion, a region of interest (ROI) was drawn, and seven major types of texture features were extracted for each color channel using the PyRadiomics package. The least absolute shrinkage and selection operator (LASSO) algorithm was used to screen key features, and multiple machine learning algorithms were used to establish a prediction model on the basis of the above texture features. The SHapley Additive exPlanations (SHAP) algorithm was applied for key feature analysis.

Results

A parathyroid gland prediction model based on white light texture features was successfully established, with the best performance achieved using the random forest (RF) algorithm. The accuracy, specificity, sensitivity, and area under the receiver operating characteristic (ROC) curve were 89.6%, 85.7%, 91.8%, 88.7%, and 77.5%, respectively. The SHAP algorithm revealed several key texture features of the parathyroid gland.

Conclusions

This study is the first to establish and validate a convenient and economical intraoperative parathyroid gland identification model, which has potential clinical application value.

Meta-Analysis of Image-Based Versus Probe-Based Parathyroid Near-Infrared Autofluorescence

Proper identification of parathyroid tissue is a critical component in surgery involving the thyroid and parathyroid gland (PG). In recent years, near infrared autofluorescence (NIRAF) has been investigated as a non-invasive strategy to detect PG in parathyroidectomy and in PG preservation in thyroidectomy. There are currently two FDA approved NIRAF modalities, image-based and probe-based. The aim of this meta-analysis is to evaluate the efficacy of these two NIRAF modalities. PubMed, Scopus, and MEDLINE were utilized, with 238 studies analyzed via independent, blinded review. Studies from January 2000 to February 2023, Boolean phrase "parathyroid autofluorescence", written in English, and included results found within the body of the article were the inclusion criteria used. Conference abstracts, reviews, case reports, commentary, discussion and letter, non-English, animal studies, in vitro studies, contrast enhanced fluorescence, and NIRAF with use of indocyanine green, were the exclusion criteria used. Five studies were enrolled based on inclusion and exclusion criteria. The estimated overall accuracy of image-based methods is 0.96 (95% CI of (0.87, 0.99)), while the estimated overall accuracy of probe-based methods is 0.93 (95% CI of (0.92, 0.94)). With p=0.36, there is insufficient evidence to indicate a significant difference in overall accuracy, sensitivity and specificity between image-based methods and probe-based methods. Both imaging and probe-based detection modalities offer effective, noninvasive means for identifying parathyroid glands intraoperatively. Further studies comparing the efficacy of these two modalities are needed to further differentiate their clinical performance.

Intraoperative Management of Parathyroid Glands and Long-Term Outcome of Parathyroid Function Following Total Thyroidectomy

Background/Objectives: In situ preservation is the primary strategy to preserve parathyroid gland (PG) function during thyroid surgery, while autotransplantation is used when inadvertent removal or devascularization occurs. Deciding on the optimal approach intraoperatively for exposed PGs remains challenging. This study evaluates intraoperative PG management strategies and long-term outcomes of PG function following total thyroidectomy. Methods: This retrospective study included 543 patients undergoing primary total thyroidectomy, excluding those with comorbid parathyroid disease. A stabbing test assessed the vascular supply of exposed PGs. PGs with fresh blood oozing after the test were preserved in situ; otherwise, they were autotransplanted. Intact parathyroid hormone (iPTH) and ionized calcium (iCa) were measured preoperatively and on postoperative day 1 (PO-1D), and during follow-up. Permanent hypoparathyroidism (PHPS) was defined as iPTH < 15 pg/mL, iCa < 4.2 mg/dL, or continued need for calcitriol or calcium supplementation after a postoperative period of 12 months (PO-12M). The PHPS rate was compared with the corresponding intraoperative PG status. Results: A total of 528 patients were enrolled in this study. At PO-1D, 434 patients (82.2%) had iPTH ≥ 15 pg/mL, 65 (12.3%) had iPTH between 4 and 15 pg/mL, and 29 (5.5%) had iPTH < 4 pg/mL. At PO-12M, 527 patients (99.81%) had iPTH ≥ 15 pg/mL, 1 (0.19%) had iPTH between 4 and 15 pg/mL, and none had iPTH < 4 pg/mL. Five patients (0.95%) were in PHPS after PO-12M. Among the 462 patients with at least one viable PG preserved in situ, the PHPS rate was 0.2%, compared to 6.1% (66 patients) for those without a viable PG preserved in situ (p < 0.001). Conclusions: Permanent hypoparathyroidism is rare when at least one viable PG is preserved in situ during total thyroidectomy. The stabbing test is a simple, useful, and cost-effective method to assess the vascular supply of exposed PGs, providing surgeons with essential information for intraoperative PG management.

An outcome analysis of utilizing contrast-free near-infrared autofluorescence imaging in thyroid cancer surgery: a retrospective study

BACKGROUND

Hypoparathyroidism is the most common complication of thyroid surgery. The best way to assume normal parathyroid gland (PTG) function is to preserve them in situ, undamaged. Near-infrared autofluorescence (NIRAF)-imaging has been introduced as a potentially useful adjunct in thyroid surgery.

OBJECTIVE

To assess the surgical outcomes of NIRAF-imaging utility in thyroid surgery.

METHODS

The clinical records of patients who underwent surgery for papillary thyroid carcinoma (PTC) in a 7-month period were retrospectively reviewed. The primary endpoint was to assess NIRAF's impact on postoperative hypoparathyroidism. Secondary endpoints included its impact in preventing inadvertent PTG resection, time to resolution of postoperative hypoparathyroidism, and additional benefits in therapeutic central compartment neck dissection (tCCND).

RESULTS

Fifty consecutive patients underwent surgery for PTC. Total thyroidectomy was performed in 42 patients. Whereas concomitant tCCND was performed in 8 patients. PTG-detection rate was 93% for NIRAF versus 87% for the surgeon (p = 0.04). NIRAF prevented inadvertent resection of 16 PTGs (p < 0.001). In tCCND, the detection rate of NIRAF was 100% versus 81% for the surgeon (p < 0.01). The rate of transient hypoparathyroidism applying NIRAF was 12% versus 15% (historical cohort) (p = 0.6). However, a significantly prompter resolution of hypoparathyroidism was demonstrated using NIRAF (average time of 2.7 weeks vs. 12.3 weeks; p < 0.0001).

CONCLUSION

Although NIRAF did not significantly minimize the overall risk of postoperative transient hypoparathyroidism, it demonstrated a trend toward improvement. It also led to prompter resolution of hypoparathyroidism and lowered the risk for inadvertent PTG resection. Therefore, NIRAF seems to be a promising surgical adjunct.

Predictors, Trends, and Outcomes of Parathyroid Autotransplantation in Pediatric Total Thyroidectomy

INTRODUCTION

Assess temporal utilization trends, identify predictors, and compare early postoperative outcomes of parathyroid autotransplantation (PTAT) in pediatric total thyroidectomy (TT) patients.

METHODS

Patients <18 y undergoing TT between 2015 and 2021 were obtained from the National Surgical Quality Improvement Program-Pediatric database. Characteristics and outcomes were described and stratified by extent of node dissection. Temporal trends and predictors of PTAT were evaluated by multivariable logistic regression. Propensity score matching was used to compare PTAT clinical outcomes.

RESULTS

Among 2444 children (median age 14.9 y), 78% had thyroidectomy alone, 17% had thyroidectomy with central lymph node dissection, and 5% had thyroidectomy with modified radical neck dissection. Of the 150 patients who underwent PTAT, 62% were transplanted in the neck and 38% in the forearm. Overall, 0.6% had nerve injury/repair, 14% had prolonged postoperative hospitalization, and 0.9% was readmitted for hypocalcemia. Utilization of PTAT decreased over time. Predictors included adult general surgery/otolaryngology subspecialty (odds ratio 2.0, 95% confidence interval 1.3-3.2, P = 0.005) and extent of node dissection (odds ratio 3.2, 95% confidence interval 1.9-5.5, P < 0.0001). No significant differences in prolonged hospitalization (18% versus 13%, P = 0.10) or readmission for hypocalcemia (2.7% versus 1.1%, P = 0.23) were observed on propensity score matching.

CONCLUSIONS

PTAT in pediatric TT is more commonly performed by adult subspecialty surgeons and in the setting of more extensive node dissections. PTAT utilization decreased over time. No significant differences in early postoperative outcomes were observed between cohorts. Further studies are needed to guide optimal parathyroid preservation strategies in children.

Post-thyroidectomy hypoparathyroidism: A clinical surgical dilemma

Thyroid dysfunction directly affects human health and overall well-being; various approaches are available for the treatment of thyroid diseases, including conservative measures and surgical interventions. Despite advancements in conservative treatment, surgery remains the preferred option. Hypoparathyroidism is the primary cause of hospitalization after thyroidectomy, leading to cost-related concerns and a detrimental impact on patients' overall quality of life. Postoperative hypoparathyroidism can result in hypocalcemia, and these are challenging conditions that must be identified promptly to prevent immediate and long-term complications. This article focused on the presentation, risk factors, and management of hypoparathyroidism to increase awareness of the risks associated with certain variables, thereby enhancing our ability to predict the risk of this condition. Furthermore, this review highlighted the surgical techniques that may be utilized to prevent hypoparathyroidism. These considerations can help guide preoperative discussions regarding the benefits and potential risks of thyroidectomy.

Methylene Blue Spray as a Tool for Safe Thyroidectomy

Background The complex surgical anatomy and intricate structural arrangement of the thyroid region pose significant challenges for surgeons in identifying the parathyroids and recurrent laryngeal nerve (RLN) during thyroid surgeries. Therefore, it is crucial to develop techniques that enhance the identification of these structures and reduce complications during thyroidectomies. Objective This study intends to assess the efficacy and diagnostic value of Methylene Blue dye and its usefulness in identifying, conserving and minimizing injury to parathyroid glands and recurrent laryngeal nerve during thyroidectomies. Methods Over two years, 66 patients had near-total, subtotal, or total thyroidectomies at the Shri BM Patil Medical College, Hospital & Research Centre, Vijayapura, India, as part of this interventional study. The time it took for various tissues to return to their natural colour after applying methylene blue dye was the principle used for safe thyroidectomy. Preoperative serum calcium and parathyroid hormone (PTH) concentrations, preoperative diagnoses, and demographic information were gathered for the study. Documentation was also kept of the histological confirmation, hospital stay following surgery, complications following surgery, variations in blood calcium and PTH concentrations on the fifth postoperative day, and any allergic reactions to methylene blue. This allowed for the calculation of equal sensitivity and specificity with negative and positive predictive values. Results Sixty-three (95%) of the 66 patients were female, most in their 40s-60s. Before surgery, patients' serum PTH and calcium levels were normal, with no patients having hoarseness of voice or hypocalcemia symptoms. Postoperative hospital stays typically lasted three to five days. Two patients experienced vocal cord paresis following surgery, and one patient experienced delayed wound healing. They were eventually able to recover fully. On day five following surgery, there was no drop in serum PTH or calcium levels and no allergic reaction to methylene blue. Methylene blue showed a sensitivity of 98.46%, specificity of 97.01%, positive predictive value of 96.97%, negative predictive value of 98.48%, and overall accuracy of 97.73% when used for intraoperative structure detection. Conclusion Using methylene blue dye for the intraoperative identification and preservation of parathyroid glands and the recurrent laryngeal nerve is a reliable, affordable, and accessible method with good sensitivity and specificity. It makes thyroidectomy dissections less taxing and reduces the risk of complications following thyroid operations.

Enhancing parathyroid preservation in papillary thyroid carcinoma surgery using nano-carbon suspension

This study evaluates the clinical significance of nano-carbon suspension in total thyroidectomy with cervical lymph node dissection for papillary thyroid carcinoma (PTC). The objective of this study was to assess the efficacy of nano-carbon suspension in enhancing parathyroid gland preservation, reducing postoperative complications, and improving surgical precision. A retrospective analysis on 219 PTC patients who underwent total thyroidectomy with cervical lymph node dissection between March 2014 and March 2018 was conducted. Patients were divided into two groups: an experimental group (n = 107) that received nano-carbon suspension and a control group (n = 112) that did not. Comparative analyses included demographics, surgical parameters, postoperative calcium and parathyroid hormone (PTH) levels, the number of dissected lymph nodes, and the incidence of complications. Baseline characteristics, including age, sex, and BMI, showed no statistically significant differences between the experimental and control groups. Postoperative calcium levels were significantly more stable in the experimental group, with median levels of 2.22 mmol/L on day 1 versus 2.06 mmol/L in the control group (P < 0.001), and 2.29 mmol/L at week 1 versus 2.22 mmol/L (P < 0.001). PTH levels were higher in the experimental group (35 pg/mL on day 1 versus 28 pg/mL, P < 0.001; 37 pg/mL at week 1 versus 30 pg/mL, P < 0.001). The experimental group had a greater median number of dissected lymph nodes (median 11.00 versus 7.00, P < 0.001) and a lower pathological parathyroid gland count (6.5% versus 23.2%, P < 0.001). Postoperative numbness and twitching were significantly reduced (4.7% versus 16.1%, P = 0.006), and the recurrence rate at 12 months was lower (4.7% versus 12.5%, P = 0.040). The use of Nano-carbon suspension in thyroidectomy and cervical lymph node dissection for PTC enhances parathyroid gland preservation, improves surgical precision, and reduces specific postoperative complications, supporting its standard adoption in thyroid cancer surgeries to optimize patient outcomes.

Redo Thyroidectomy: Updated Insights

The risk of post-operatory hypothyroidism and hypocalcaemia, along with recurrent laryngeal nerve injury, is lower following a less-than-total thyroidectomy; however, a previously unsuspected carcinoma or a disease progression might be detected after initial surgery, hence indicating re-intervention as mandatory (so-called "redo" surgery) with completion. This decision takes into consideration a multidisciplinary approach, but the surgical technique and the actual approach is entirely based on the skills and availability of the surgical team according to the standard protocols regarding a personalised decision. We aimed to introduce a review of the most recently published data, with respect to redo thyroid surgery. For the basis of the discussion, a novel vignette on point was introduced. This was a narrative review. We searched English-language papers according to the key search terms in different combinations such as "redo" and "thyroid", alternatively "thyroidectomy" and "thyroid surgery", across the PubMed database. Inclusion criteria were original articles. The timeframe of publication was between 1 January 2020 and 20 July 2024. Exclusion criteria were non-English papers, reviews, non-human studies, case reports or case series, exclusive data on parathyroid surgery, and cell line experiments. We identified ten studies across the five-year most recent window of PubMed searches that showed a heterogeneous spectrum of complications and applications of different surgeries with respect to redo interventions during thyroid removal (e.g., recurrent laryngeal nerve monitoring during surgery, other types of incision than cervicotomy, the use of parathyroid fluorescence, bleeding risk, etc.). Most studies addressing novel surgical perspectives focused on robotic-assisted re-intervention, and an expansion of this kind of studies is expected. Further studies and multifactorial models of assessment and risk prediction are necessary to decide, assess, and recommend redo interventions and the most adequate surgical techniques.

Parathyroid gland identification and angiography classification using simple machine learning methods

BACKGROUND

Near-infrared indocyanine green angiography allows experienced surgeons to reliably evaluate parathyroid gland vitality during thyroid and parathyroid operations in order to predict postoperative function. To facilitate equal performance between surgeons, we developed an automatic computational quantification method using computer vision that portrays expert interpretation of visualized parathyroid gland near-infrared indocyanine green angiographic fluorescence signals.

METHODS

Near-infrared indocyanine green-parathyroid gland angiography video recordings (Fluobeam® LX, Fluoptics, Grenoble-part of Getinge-Göteborg) from patients undergoing endocrine cervical surgery in a high-volume unit were used for model development. Computation (MATLAB, Mathworks, Ireland) included segmentation-identification of the parathyroid gland (by autofluorescence), image stabilization (by linear translation) and adjusted time-fluorescence intensity profile generation. Relative upslope and maximum intensity ratios then trained a simple logistic regression model based on expert interpretation and outcome (including hypoparathyroidism), with subsequent unseen testing for validation.

RESULTS

The model was trained on 37 patient videos (45 glands, 29 judged well perfused by parathyroid gland angiography experts), achieving feature data separation with 100% accuracy, and tested on 22 unseen videos (27 glands, 15 judged well perfused), including four in real time. Segmentation-guided parathyroid gland detection correctly identified all parathyroid glands during unseen testing along with three additional non-parathyroid gland regions (90% positive predictive value). Subsequent time-fluorescence intensity profile extraction with vitality prediction was shown feasible in all cases within 5 min, with a 96.3% model accuracy (sensitivity and specificity were 93.3 and 100% respectively) when compared with expert judgement.

CONCLUSION

Automatic parathyroid gland perfusion quantification using simple machine learning computational methods discriminates parathyroid gland perfusion in concordance with expert surgeon interpretation, providing a means for near-infrared indocyanine green-parathyroid gland signal evaluation.

Risk Factors for Transient and Permanent Hypoparathyroidism Following Thyroidectomy: A Comprehensive Review

Hypoparathyroidism is a common complication following thyroidectomy, resulting in significant disturbances in calcium homeostasis due to low parathyroid hormone (PTH) levels. This comprehensive review examines the risk factors associated with transient and permanent hypoparathyroidism post-thyroidectomy, emphasizing surgical, patient-related, and perioperative factors. Transient hypoparathyroidism, characterized by temporary hypocalcemia resolving within weeks to months, is often managed with short-term calcium and vitamin D supplementation. In contrast, permanent hypoparathyroidism persists beyond six months post-surgery, necessitating lifelong supplementation and potentially PTH replacement therapy. The review delves into the anatomy and physiology of the parathyroid glands, mechanisms leading to hypoparathyroidism, and incidence rates. Surgical factors such as the extent of thyroidectomy, surgeon expertise, and intraoperative parathyroid gland preservation are critical in determining the risk of hypoparathyroidism. Patient factors, including age, sex, pre-existing conditions, and perioperative management, influence outcomes. Diagnostic and monitoring strategies, along with management protocols for both transient and permanent hypoparathyroidism, are discussed. Prevention strategies, emerging research, future surgical techniques, and intraoperative monitoring directions are highlighted to improve clinical outcomes. This review aims to enhance understanding, inform surgical practices, and optimize postoperative care to minimize the incidence and impact of hypoparathyroidism in thyroidectomy patients.

Risk factors of transient and permanent hypoparathyroidism after thyroidectomy: a systematic review and meta-analysis

BACKGROUND

Postoperative hypoparathyroidism (hypoPT) is a common complication following thyroid surgery. However, current research findings on the risk factors for post-thyroid surgery hypoPT are not entirely consistent, and the same risk factors may have different impacts on transient and permanent hypoPT. Therefore, there is a need for a comprehensive study to summarize and explore the risk factors for both transient and permanent hypoPT after thyroid surgery.

MATERIALS AND METHODS

Two databases (PubMed and Embase) were searched from inception to 2024. The Newcastle-Ottawa Scale was used to rate study quality. Pooled odds ratios were used to calculate the relationship of each risk factor with transient and permanent hypoPT. Subgroup analyses were conducted for hypoPT with different definition-time (6 or 12 months). Publication bias was assessed using Begg's test and Egger's test.

RESULTS

A total of 19 risk factors from the 93 studies were included in the analysis. Among them, sex and parathyroid autotransplantation were the most frequently reported risk factors. Meta-analysis demonstrated that sex (female vs. male), cN stage, central neck dissection, lateral neck dissection, extent of central neck dissection (bilateral vs. unilateral), surgery [total thyroidectomy (TT) vs. lobectomy], surgery type (TT vs. sub-TT), incidental parathyroidectomy, and pathology (cancer vs. benign) were significantly associated with transient and permanent hypoPT. Preoperative calcium and parathyroid autotransplantation were only identified as risk factors for transient hypoPT, while preoperative PTH was a protective factor. Additionally, node metastasis and parathyroid in specimen were associated with permanent hypoPT.

CONCLUSION

The highest risk of hypoPT occurs in female thyroid cancer patients with lymph node metastasis undergoing TT combined with neck dissection. The key to preventing postoperative hypoPT lies in the selection of surgical approach and intraoperative protection.

Silicon-Rhodamine Functionalized Evocalcet Probes Potently and Selectively Label Calcium Sensing Receptors In Vitro, In Vivo, and Ex Vivo

The calcium sensing receptor (CaSR) is a ubiquitously expressed G-protein coupled receptor (GPCR) that regulates extracellular calcium signals via the parathyroid glands. CaSR has recently also been implicated in noncalcitropic pathophysiologies like asthma, gut inflammation, and cancer. To date, molecular tools that enable the bioimaging of CaSR in tissues are lacking. Based on in silico analyses of available structure-activity relationship data on CaSR ligands, we designed and prepared silicon-rhodamine (SiR) conjugates of the clinically approved drug evocalcet. The new probes EvoSiR4 and EvoSiR6, with differing linker lengths at the evocalcet carboxyl end, both showed a 6-fold and 3-fold increase in potency toward CaSR (EC50 < 45 nM) compared to evocalcet and the evocalcet-linker conjugate, respectively, in an FLIPR-based cellular functional assay. The specificity of the EvoSiR probes toward CaSR binding and the impact of albumin was evaluated in live cell experiments. Both probes showed strong albumin binding, which facilitated the clearance of nonspecific binding interactions. Accordingly, in zebrafish embryos, EvoSiR4 specifically labeled the high CaSR expressing neuromasts of the lateral line in vivo. EvoSiR4 was also assessed in human parathyroid tissues ex vivo, showing a specific absolute CaSR-associated fluorescence compared to that of parathyroid autofluorescence. In summary, functionalization of evocalcet by SiR led to the preparation of potent and specific fluorescent CaSR probes. EvoSiR4 is a versatile small-molecular probe that can be employed in CaSR-related biomedical analyses where antibodies are not applicable.

5-year Follow-up of Reimplanted Parathyroid Glands in Forearm Subcutaneous Tissue During Thyroidectomy. A Confirmation of Graft Vitality in a Large Series of Patients

INTRODUCTION

The aim of this study is to assess the outcomes of parathyroid gland reimplantation with PR-FaST technique in patients undergoing thyroid surgery, focusing on graft functionality over a 5-year follow-up period.

MATERIALS AND METHODS

We analyzed data from 131 patients who underwent parathyroid reimplantation using the PR-FaST technique during thyroid surgery due to inadvertent parathyroid removal or evident vascular damage. Postoperative evaluations included serum calcium (Ca), magnesium (Mg), and phosphorus (P) analyses on the 1st and 2nd postoperative days, at 10 days, and at 1, 3, 6 months, 1 year, and 5 years of follow-up. Additionally, the mean values of serum intact parathyroid hormone (iPTH) concentration were measured from blood samples collected from both the reimplanted arm (iPTH RA) and non-reimplanted arm (iPTH NRA) within the same period.

RESULTS

Among 131 patients, at 10 days post-surgery, only 46 patients (35.1%) out of 131 exhibited graft viability (iPTH ratio >1.5). This percentage increased to 72.8% (94 patients) after 1 month and further to 87.8% (108 patients) after 3 months post-surgery. At 1 year, 84.7% of patients showed good graft functionality. After 5 years, the percentage remained stable, with graft viability observed in 81.3% of patients. Only 91 of the initial 131 patients completed follow-up up to 5 years, with a dropout rate of 30.5 %.

CONCLUSIONS

Parathyroid reimplantation using the PR-FaST technique is a viable option for patients undergoing thyroidectomy and has been shown to be a reproducible and effective technique in most patients, with sustained graft functionality and parathyroid hormone production over a 5-year follow-up period.

Intraoperative indocyanine green angiography for predicting postoperative hypoparathyroidism

BACKGROUND

Postoperative hypocalcemia is a common complication of thyroidectomy. This problem is most often associated with accidental devascularization or excision of the parathyroid glands (PG).

AIM

Aim was to study near-infrared (NIR) fluorescent imaging with intraoperative PG indocyanine green (ICG) angiography to help identify and preserve PG during total thyroidectomy in order to avoid postoperative hypocalcemia.

MATERIAL AND METHODS

From 2017 to 2022, a total of 92 patients underwent total thyroidectomy at Odessa Regional Hospital. Indications for surgery were multinodular goiter (n = 42), thyroid cancer (n = 43), and Graves' disease (n = 7). By randomization all patients were divided into two groups: in the control group, 48 patients underwent standard total thyroidectomy, and in the main group, 44 patients underwent NIR-assisted total thyroidectomy with ICG angiography. Serum calcium and parathyroid hormone levels were compared between the two groups of patients in 1, 7-15 days after surgery and then 3, 6 months later.

RESULTS

In the control group, based on a visual assessment of the PG, autotransplantation of the PG was conducted in only five cases. In the second group, autotransplantation was performed in 16 patients. The transient postoperative hypocalcemia was observed in 8 patients of the control group (16, 70%) and in the 2 patients of ICG group (4, 50%) on 5-10 postoperative days. In the first group, 2 patients at 3 months after surgery had permanent hypocalcaemia.

CONCLUSION

NIR fluorescent imaging with intraoperative PG ICG angiography is a safe and an easily repeatable method. This technique provides improved detecting and assessment of the perfusion of the PG. The need for autotransplantation of the PG can be determined more objectively using ICG imaging than simple visualization.