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

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.

Hungry bone syndrome following thyroid surgery

The diagnosis of hypocalcemia-induced tetany following a total thyroidectomy is not common. However, there is a higher risk in patients with a history of gastric bypass surgery due to their malabsorption condition. This case describes postoperative hungry bone syndrome resulting from chronic malabsorption in a patient with a history of bariatric surgery. It is important to consider alternative treatment options if the initial management proves ineffective. Typically, this is a temporary condition, but it's crucial to prioritize prevention in high-risk patients by providing perioperative calcium and vitamin D supplementation.

Pre-incisional, trans-isthmic injection of indocyanine green for lymph node mapping during the transoral endoscopic thyroidectomy vestibular approach

Indocyanine green (ICG) is a useful tracer for lymph node mapping and retrieval. However, during endoscopic surgery, it is challenging to administer ICG into the thyroid without spillage. We developed a simple technique of delivering ICG, thereby preventing leakage. Patients who underwent the transoral endoscopic thyroidectomy were retrospectively reviewed. In 20 patients, who constituted the ICG group, 0.1 mL ICG was injected into the peri-tumoral space under ultrasound guidance, soon after the patients received general anesthesia. Patients with papillary thyroid carcinoma who did not receive the ICG injection comprised the control group (n = 43). The location, size, and number of harvested lymph nodes were recorded in conjunction with parathyroid-related parameters. No ICG spillage occurred in the ICG group, and 76 ICG-stained lymph nodes were detected in the pretracheal (57.9%), paratracheal (25.0%), and prelaryngeal regions (17.1%). The ICG group demonstrated a significantly higher number of total (5.3 vs 2.1) and metastatic (1.5 vs 0.6) lymph nodes, a larger metastatic deposit in the positive node (3.5 mm vs 1.6 mm), and a higher rate of pathologically node-positive disease (70.0% vs 27.9%) than did the control group. The postoperative calcium level (7.8 mg/dL vs 7.2 mg/dL) was also higher in the ICG group. Pre-incisional, trans-isthmic injection of ICG under ultrasound guidance is a simple technique to prevent the leakage of ICG. Under fluorescence imaging, an adequate number of lymph nodes can be harvested for examination, which may assist in intraoperative decision-making.

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.

Advancements in Thyroidectomy: A Mini Review

Demand for minimally invasive surgery has driven the development of new gadgets and surgical techniques. Yet, questions about safety and skeptical views on new technology have prevented proliferation of new modes of surgery. This skepticism is perhaps due to unfamiliarity of new fields. Likewise, there are currently various remote-access techniques available for thyroid surgeons that only few regions in the world have adapted. This review will explore the history of minimally invasive techniques in thyroid surgery and introduce new technology to be implemented.

Clinical application of parathyroid autotransplantation in endoscopic radical resection of thyroid carcinoma

Purpose

This study aimed to examine the effect of selective inferior parathyroid gland autotransplantation on central lymph node dissection(CLND) and incidence of postoperative hypoparathyroidism in patients undergoing endoscopic radical resection of thyroid carcinoma.

Methods

The data of 310 patients undergoing endoscopic radical resection of thyroid carcinoma will be retrospectively analyzed. The patients will be divided into the experimental group and the control group according to whether they combined with parathyroid autotransplantation. Statistics of the incidence rate of postoperative hypoparathyroidism, the concentration of PTH and Calcium in the systemic circulation at different time points in the two groups, the concentration of PTH in the cubital fossa vein in the transplantation region in the experimental group, and the number of central lymph nodes and positive lymph nodes dissection will be carried out.

Results

The incidence rate of temporary and permanent hypoparathyroidism in the experimental group was 33.75% and 0.625%, respectively, and in the control group was 22% and 5%, respectively; its difference was statistically significant (X^{2 =} 10.255, P=0.006). Parathyroid autotransplantation increased incidence of transient hypoparathyroidism (OR, 1.806; Cl, 1.088-2.998; P=0.022), and lower incidence of permanent hypoparathyroidism (OR, 0.112; Cl, 0.014-0.904; P=0.040). The diameters of thyroid cancer nodules was not associated with the occurrence of transient hypoparathyroidism (OR, 0.769; Cl, 0.467-1.265; P=0.301) or permanent hypoparathyroidism (OR, 1.434; Cl, 0.316-6.515; P=0.641). Comparison of systemic circulation PTH, between the two groups showed that the PTH of patients in the experimental group was higher than that in the control group from 1 week to 12 months after the operation, and the difference was statistically significant (P<0.05). In the experimental group, from 1 week to 12 months after surgery, PTH concentrations was significantly higher in the cubital fossa of the transplantation side than in the contralateral side, and the differences were statistically significant (P<0.05). The mean number of central lymph node dissected per patient was significantly higher in the experimental group (7.94 ± 3.03 vs. 6.99 ± 2.86; P <0.05); The mean number of positive nodes per patient was significantly higher in the experimental group (3.16 ± 1.86 vs. 2.53 ± 1.59; P <0.05).

Conclusions

In endoscopic radical resection of thyroid carcinoma, parathyroid autotransplantation is more beneficial to postoperative parathyroid glands function recovery, effectively preventing postoperative permanent hypoparathyroidism and realizing more thorough CLND.

Impact of parathyroidectomy on quality of life in multiple endocrine neoplasia type 1

BACKGROUND

Potential influences of parathyroidectomy (PTx) on the quality of life (QoL) in multiple endocrine neoplasia type 1-related primary hyperparathyroidism (HPT/MEN1) are unknown.

METHOD

Short Form 36 Health Survey Questionnaire was prospectively applied to 30 HPT/MEN1 patients submitted to PTx (20, subtotal; 10, total with autograft) before, 6 and 12 months after surgery. Parameters that were analyzed included QoL, age, HPT-related symptoms, general pain, comorbidities, biochemical/hormonal response, PTx type and parathyroid volume.

RESULTS

Asymptomatic patients were younger (30 vs 38 years; P = 0.04) and presented higher QoL scores than symptomatic ones: Physical Component Summary score (PCS) 92.5 vs 61.2, P = 0.0051; Mental Component Summary score (MCS) 82.0 vs 56.0, P = 0.04. In both groups, QoL remained stable 1 year after PTx, independently of the number of comorbidities. Preoperative general pain was negatively correlated with PCS (r = -0.60, P = 0.0004) and MCS (r = -0.57, P = 0.0009). Also, moderate/intense pain was progressively (6/12 months) more frequent in cases developing hypoparathyroidism. The PTx type and hypoparathyroidism did not affect the QoL at 12 months although remnant parathyroid tissue volume did have a positive correlation (P = 0.0490; r = 0.3625) to PCS 12 months after surgery. Patients with one to two comorbidities had as pre-PTx PCS (P = 0.0015) as 12 months and post-PTx PCS (P = 0.0031) and MCS (P = 0.0365) better than patients with three to four comorbidities.

CONCLUSION

A variable QoL profile was underscored in HPT/MEN1 reflecting multiple factors associated with this complex disorder as comorbidities, advanced age at PTx and presence of preoperative symptoms or of general pain perception. Our data encourage the early indication of PTx in HPT/MEN1 by providing known metabolic benefits to target organs and avoiding potential negative impact on QoL.

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.