Use of fluorescence imaging and indocyanine green during thyroid and parathyroid surgery: Results of an intercontinental, multidisciplinary Delphi survey

Thyroid surgery under nerve auto-fluorescence & artificial intelligence tissue identification software guidance

Thyroid cancer is a common malignancy that requires comprehensive clinical evaluation prior to adequate surgical management. Over the last three decades thyroid surgery has tripled and is considered one of the most commonly performed procedures in general surgery. These procedures are associated with potential postoperative complications with significant deterioration in the patient's quality of life. While the current rates of recurrent laryngeal nerve injury following thyroidectomy have decreased secondary to intraoperative neuromonitoring, thyroid surgery remains the leading cause of iatrogenic injury. The authors herein present a case of a thyroid nodule with cervical lymph node involvement undergoing total thyroidectomy guided by near-ultraviolet (NUV) imaging nerve auto-fluorescent technology to visualize, identify and protect vital structures.

[Modern thyroid surgery : Efficient and safe thyroidectomy technique]

After decades of bilateral "subtotal" and later "total" thyroidectomy, the extent of resection is now determined individually depending on the dominant thyroid condition. The leading indication by far in the study, documentation and quality center (StuDoQ) register of the Surgical Working Group Endocrinology (CAEK) is currently the suspicion of malignancy, which is followed by benign symptomatic nodular goiter, functional disorders and confirmed malignancy. The decision for an intervention as well as the extent of resection must be rigorously established. Aids for intraoperative nerve monitoring, vessel-sealing and parathyroid autofluorescence increase the safety of thyroid resections but also the complexity. The surgical technique of lobectomy using modern devices for vessel sealing is an intricate process in which the positioning, access to the neck and a modified sequence of dissection steps are equally important. While the usefulness of neuromonitoring is nowadays no longer in doubt, this is not yet so clear for other technologies. Above all, however, modern thyroid surgery is characterized by the knowledge of one's own results and a clear positioning to follow-ups. The selection of any surgical aid should be based on this knowledge.

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.

Optimizing Indocyanine Green Dosage for Near-Infrared Fluorescence Perfusion Assessment in Bowel Anastomosis: A Prospective, Systematic Dose-Ranging Study

BACKGROUND

Indocyanine green (ICG) near-infrared fluorescence (NIRF) has emerged as a promising technique for visualizing tissue perfusion. However, within the wide range of dosages and imaging conditions currently being applied, the optimal dosage of ICG remains unclear. This study aimed to investigate the feasibility and implications of implementing lower dosages of ICG than commonly used for visual and quantitative perfusion assessment in a standardized setting.

METHODS

A prospective single-center cohort study was conducted on patients undergoing ileostomy reversal by hand-sewn anastomosis. ICG-NIRF visualization was performed before (T1) and after (T2) anastomosis with one of four different dosages of ICG (5 mg, 2.5 mg, 1.25 mg, or 0.625 mg) and recorded. Postoperatively, each visualization was evaluated for signal strength, completeness, and homogeneity of fluorescence. Additionally, perfusion graphs were generated by a software-based quantitative perfusion assessment, allowing an analysis of perfusion parameters. Statistical analysis comparing the effect of the investigated dosages on these parameters was performed.

RESULTS

In total, 40 patients were investigated. Visual evaluation demonstrated strong, complete, and homogeneous fluorescence signals across all dosages. Perfusion graph assessment revealed a consistent shape for all dosages (ingress followed by egress phase). While the average signal intensity decreased with dosage, it was sufficient to enable perfusion assessment even at the lowest dosages of 1.25 mg and 0.625 mg of ICG. The baseline intensity at T2 (the second intraoperative visualization) significantly decreased with dosage. The slope of the egress phase steepened with decreasing dosage.

CONCLUSIONS

Lower dosages of ICG were sufficient for intraoperative perfusion assessment, while causing lower residual fluorescence and quicker egress in subsequent visualizations.

[First experience of applying domestic video fluorescent equipment for visualization and blood flow evaluation of the parathyroid glands]

In recent years, predictive methods for assessing the preservation of the parathyroid glands have been actively implemented. The article describes the first experience of evaluating the blood supply of the parathyroid glands by quantitative determination of the indocyanine green (ICG) accumulation index in real time in 6 patients before and after a thyroidectomy with central neck lymph node dissection for papillary thyroid cancer. Intraoperative fluorescent angiography was performed by using domestic equipment with a fluorescent module, as well as by using a domestic medication of ICG. Intraoperative values of the ICG accumulation index were compared with the levels of ionized calcium and parathyroid hormone perioperatively. No clinical manifestations of hypocalcemia were detected in the postoperative period. The obtained results showed the informativeness of the numerical assessment of the intensity of ICG fluorescence. The evaluation of the distribution (accumulation) of ICG has prospects for practical application in thyroid surgery in the formation of tactics for preserving the parathyroid glands and predicting postoperative hypoparathyreosis.

Effect of intraoperative active exploration of parathyroid glands to reduce the incidence of postoperative hypoparathyroidism, and risk factors of hypoparathyroidism after total thyroidectomy: a single-center study

Background

The risk factors for hypoparathyroidism after thyroid surgery have not been fully identified. This study analyzes the risk factors of hypoparathyroidism before and after total thyroidectomy.

Methods

We retrospectively collected the clinical data of 289 patients who underwent total thyroidectomy at the Thyroid Surgery Center of Lishui Central Hospital from June 2018 to June 2020. For the anatomy and protection of parathyroid glands during the operation, one group of patients used the parathyroid avoidance method, and the other group used the active exploration method. Various risk factors affecting parathyroid dysfunction were studied using logistic regression models.

Results

A total of 289 patients were included in this study. The average age of patients was 47.21 ± 11.78 years, including 57 males (19.7%) and 232 females (80.3%). There were 149 (51.6%) patients with transient hypoparathyroidism and 21 (7.3%) with permanent hypoparathyroidism. The main risk factors of hypoparathyroidism were parathyroid avoidance method (P = 0.005), parathyroid autotransplantation (P = 0.011), bilateral central neck lymph node dissection (CND) (P = 0.001), lymphatic metastasis (P = 0.039), and parathyroid in the specimen (P = 0.029). The main risk factors associated with permanent hypoparathyroidism were bilateral CND (P = 0.038), lymphatic metastasis (P = 0.047), parathyroid hormone (PTH) < 1.2 pg/ml within three days after surgery (P = 0.006).

Conclusion

Hypoparathyroidism is common but mostly transient after bilateral total thyroidectomy. Compared with parathyroid avoidance method, the active exploration method during operation may reduce the incidence of postoperative hypoparathyroidism. PTH <1.2 pg/ml within three days after surgery was predictive in patients with permanent hypoparathyroidism.