Autofluorescence of parathyroid glands during endocrine surgery with minimally invasive technique

Assessing the feasibility of near infrared autofluorescence imaging in minimally-invasive video assisted parathyroidectomy and the autofluorescence signature of parathyroid adenomas. A single center surgical case series

BACKGROUND

The role of near-infrared autofluorescence (NIRAF)-imaging in thyroid surgery is well-established. However, its role in hyperparathyroidism surgery is yet to be defined due to the lack of consensus regarding the autofluorescence (AF) pattern of parathyroid adenomas (PAs). Furthermore, its utility in minimally invasive video-assisted parathyroidectomy (MIVAP) has yet to be assessed.

OBJECTIVE

To assess the feasibility of utilizing NIRAF-imaging via the limited-access of MIVAP and whether PAs demonstrate a unique AF signature allowing NIRAF-imaging to serve as an intraoperative diagnostic tool.

METHODS

The clinical records of patients who underwent MIVAP for hyperparathyroidism between February and October 2024 were retrospectively reviewed. The primary endpoint was to assess the feasibility of NIRAF-imaging in MIVAP and whether PAs demonstrate a defining AF pattern. Secondary endpoints included whether certain AF patterns of PAs correlated with specific PA features including cell type, size, and/or location. Furthermore, operative-time and cost implications were assessed.

RESULTS

24 consecutive patients underwent MIVAP for hyperparathyroidism. NIRAF-imaging was feasible via the limited-access with no technical difficulties reported. AF patterns included high-intensity AF in 10 (38.5%), low-intensity AF in 10 (38.5%), and cap AF in 6 (23%). A new AF pattern was also described and referred to as "double cap AF". No significant differences in the patterns of AF were observed (p = 0.2). The pattern of AF did not considerably correlate with the predominant cell type, size or location of the PA. However, mediastinal PAs demonstrated a significantly higher tendency for cap AF. The additional time added to the procedure applying the technology was only a few minutes. However, it conferred a considerable additional cost.

CONCLUSION

In experienced hands, a direct minimal-access did not preclude utilizing NIRAF-imaging. PAs seem to lack a uniform characteristic AF signature implying a limited diagnostic role of NIRAF-imaging in parathyroid surgery apart from confirming normal parathyroid tissue. The study has been registered in ClinicalTrials.gov; registration number: NCT06779760.

The research progress of label-free optical imaging technology in intraoperative real-time navigation of parathyroid glands

Intraoperative misidentification or vascular injury to the parathyroid glands can lead to hypoparathyroidism and hypocalcemia, resulting in serious postoperative complications. Therefore, functional localization of the parathyroid glands during thyroid (parathyroid) surgery is a key focus and challenge in thyroid surgery. The current clinical prospects of various optical imaging technologies for intraoperative localization, identification, and protection of parathyroid glands varies. However, "Label-free optical imaging technology" is increasingly favored by surgeons due to its simplicity, efficiency, safety, real-time capability, and non-invasiveness. This manuscript focuses on the relatively well-researched near-infrared autofluorescence (NIRAF) and NIRAF-combined studies including those integrating laser speckle imaging, artificial intelligence(AI) optimization, hardware integration, and optical path improvements. It also briefly introduces promising technologies, including Laser-Induced Fluorescence (LIF), Hyperspectral Imaging (HSI), Fluorescence Lifetime Imaging (FLIm), Laser-Induced Breakdown Spectroscopy (LIBS), Optical Coherence Tomography (OCT), and Dynamic Optical Contrast Imaging (DOCI). While these technologies are still in early stages with limited clinical application and standardization, current research highlights their potential for improving intraoperative parathyroid identification. Future studies should focus on refining these methods for broader clinical use.

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.

Intraoperative strategies in identification and functional protection of parathyroid glands for patients with thyroidectomy: a systematic review and network meta-analysis

BACKGROUND

This study aimed to assess the benefits and limitations of four intraoperative visualization of parathyroid gland (IVPG) strategies in the identification and functional protection of parathyroid glands (PGs).

METHODS

We searched PubMed, the Cochrane Central Register of Controlled Trials, CNKI, EMBASE, Web of Science and Google Scholar databases until 30 June 2023. Four IVPG strategies were composed of the naked eyes (NE) and three imaging strategies: autofluorescence (AF), indocyanine green fluorescence (ICGF), and carbon nanoparticles (CN). We performed a pairwise meta-analysis (PMA) for direct comparisons and a Bayesian network meta-analysis (NMA) for indirect comparisons.

RESULTS

A total of 29 eligible studies were included. According to NMA and PMA, AF had significantly lower rates of postoperative hypocalcemia and hypoparathyroidism, PG inadvertent resection, and PG auto-transplantation compared to NE, while had significantly higher rate of PG identification. CN showed significantly lower rates of postoperative hypocalcemia and hypoparathyroidism, and PG inadvertent resection compared to NE in PMA and NMA. ICGF showed a significantly higher rate of PG auto-transplantation compared to NE in PMA and AF in NMA. According to SUCRA values, AF showed the best advantage in reducing the rate of postoperative hypocalcemia (0.85) and PG inadvertent resection (0.89), and increasing the rate of PG identification (0.80). CN had the greatest advantage in reducing the rate of postoperative hypoparathyroidism (0.95). ICGF ranked the highest in the rate of PG auto-transplantation (0.98).

CONCLUSIONS

Three imaging strategies demonstrate significant superiority over NE in the intraoperative PG identification and functional protection. AF is the best strategy in reducing the incidence of postoperative hypocalcemia, increasing the rate of PG identification, and reducing the rate of PG inadvertent resection and auto-transplantation. ICGF has great value in assessing PG viability, leading to the trend towards PG auto-transplantation. CN is the best strategy in reducing the incidence of postoperative hypoparathyroidism.

Management of surgical diseases of thyroid gland indications of the United Italian Society of Endocrine Surgery (SIUEC)

A task force of the United Italian society of Endocrine Surgery (SIUEC) was commissioned to review the position statement on diagnostic, therapeutic and health‑care management protocol in thyroid surgery published in 2016, at the light of new technologies, recent oncological concepts, and tailored approaches. The objective of this publication was to support surgeons with modern rational protocols of treatment that can be shared by health-care professionals, taking into account important clinical, healthcare and therapeutic aspects, as well as potential sequelae and complications. The task force consists of 13 members of the SIUEC highly trained and experienced in thyroid surgery. The main topics concern clinical evaluation and preoperative workup, patient preparation for surgery, surgical treatment, non-surgical options, postoperative management, prevention and management of major complications, outpatient care and follow-up.

The magic mirror: a novel intraoperative monitoring method for parathyroid glands

The accurate detection of parathyroid glands (PGs) during surgery is of great significance in thyroidectomy and parathyroidectomy, which protects the function of normal PGs to prevent postoperative hypoparathyroidism and the thorough removal of parathyroid lesions. Existing conventional imaging techniques have certain limitations in the real-time exploration of PGs. In recent years, a new, real-time, and non-invasive imaging system known as the near-infrared autofluorescence (NIRAF) imaging system has been developed to detect PGs. Several studies have confirmed that this system has a high parathyroid recognition rate and can reduce the occurrence of transient hypoparathyroidism after surgery. The NIRAF imaging system, like a magic mirror, can monitor the PGs during surgery in real time, thus providing great support for surgeries. In addition, the NIRAF imaging system can evaluate the blood supply of PGs by utilizing indocyanine green (ICG) to guide surgical strategies. The NIRAF imaging system and ICG complement each other to protect normal parathyroid function and reduce postoperative complications. This article reviews the effectiveness of the NIRAF imaging system in thyroidectomies and parathyroidectomies and briefly discusses some existing problems and prospects for the future.

Calcitriol supplementation before parathyroidectomy and calcium level after surgery in parathyroid adenoma patients: a randomized controlled trial

BACKGROUND

Hypocalcemia is the most common complication after parathyroidectomy, contributing to extended hospital stays and higher hospitalization costs. The present study aimed to evaluate whether preoperative Calcitriol could help reduce hypocalcemia rates.

METHOD

In this randomized controlled trial, we included 80 patients with primary hyperparathyroidism candidates for parathyroidectomy. The intervention group received Calcitriol 0.25 µg/day 1 week before parathyroidectomy. Baseline laboratory data, parathyroid hormone level (before, during, after 5, and 10 min of operation), calcium level (6, 24, and 48 h after operation), and clinical signs and symptoms were recorded.

RESULTS

Of the 80 participants, 40 (mean age: 53.36 ± 12.97) were randomized to the intervention, and 40 (mean age: 52.84 ± 12.32) to the control group. There were no statistically significant differences in age, tumor size, gender, baseline laboratory data, intra-operative PTH, and calcium level 6 and 24 h after the operation. We observed a significantly higher calcium level in the intervention group 48 h post-operation (8.57 ± 0.30 vs. 8.33 ± 0.38). Also, days of hospital stay and symptomatic hypocalcemia rate were significantly lower in the intervention group.

CONCLUSION

In patients with primary hyperparathyroidism, preoperative Calcitriol may be of value in preventing post-parathyroidectomy hypocalcemia and subsequent complications.