Preliminary experience with the EleVision IR system in detection of parathyroid glands autofluorescence and perfusion assessment with ICG

State of the art medical devices for fluorescence-guided surgery (FGS): technical review and future developments

BACKGROUND

Medical devices for fluorescence-guided surgery (FGS) are becoming available at a fast pace. The main challenge for surgeons lies in the lack of in-depth knowledge of optical imaging, different technical specifications and poor standardisation, and the selection of the best device based on clinical application.

METHODS

This manuscript aims to provide an up-to-date description of the commercially available fluorescence imaging platforms by comparing their mode of use, required settings, image types, compatible fluorophores, regulatory approval, and cost. We obtained this information by performing a broad literature search on PubMed and by contacting medical companies directly. The data for this review were collected up to November 2023.

RESULTS

Thirty-two devices made by 19 medical companies were identified. Ten systems are surgical microscopes, 5 can be used for both open and minimally invasive surgery (MIS), 6 can only be used for open surgery, and 10 only for MIS. One is a fluorescence system available for the Da Vinci robot. Nineteen devices can provide an overlay between fluorescence and white light image. All devices are compatible with Indocyanine Green, the most common fluorescence dye used intraoperatively. There is significant variability in the hardware and software of each device, which resulted in different sensitivity, fluorescence intensity, and image quality. All devices are CE-mark regulated, and 30 were FDA-approved.

CONCLUSION

There is a prolific market of devices for FGS and healthcare professionals should have basic knowledge of their technical specifications to use it at best for each clinical indication. Standardisation across devices must be a priority in the field of FGS, and it will enhance external validity for future clinical trials in the field.

Initial Experience With Ultra-High-Definition 3D Exoscope in Thyroid and Parathyroid Surgery

BACKGROUND

Operation with a 3D exoscope has recently been introduced in clinical practice. The exoscope consists of two cameras placed in front of the operative field. Images are shown on a large 3D screen with high resolution. The system can be used to enhance precise dissection and provides new possibilities for improved ergonomics, fluorescence, and other optical-guided modalities.

METHODS

Initial experience with the ultra-high-definition (4K) 3D exoscope in thyroid and parathyroid operations. The exoscope (OrbEyeTM) was mounted on a holding system (Olympus).

RESULTS

We used the exoscope in parathyroidectomy (N = 6) and thyroidectomy (N = 6). Immediate advantages and disadvantages were discussed and recorded. The learning curve for use of the exoscope may be shorter for surgeons with training in endoscopic or robotic procedures. There may be improved ergonomics compared with normal open-neck operations. Further, the optical guided operations can be used with fluorescence and have potential for different on-lay techniques in the future. The 4 K 3D image quality is state-of-art and is highly appreciated during fine surgical dissection and eliminates the need for loupes.

CONCLUSION

In several ways, using the ORBEYE™ in thyroid and parathyroid surgery provides the surgical team with a new and enhanced experience. This includes improved possibility for teaching, surgical ergonomics, and a 4K 3D camera with a powerful magnification system. However, it is not clear if utilization of these features would improve surgical outcomes. Furthermore, the ORBEYE™ lacks incorporation of parathyroid autofluorescence, and the current costs for the system do not facilitate general access to exoscope assisted operations.

Management of surgical diseases of Primary Hyperparathyroidism: 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 parathyroid surgery published in 2014, 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 12 members of the SIUEC highly trained and experienced in thyroid and parathyroid surgery. The main topics concern diagnostic test and localization studies, mode of admission and waiting time, therapeutic pathway (patient preparation for surgery, surgical treatment, postoperative management, management of major complications), hospital discharge and patient information, outpatient care and follow-up, outpatient initial management of patients with pHPT.

Feasibility of Autofluorescence Using Overlay Imaging for the Detection of Parathyroid Glands: Defining Standards

BACKGROUND

The aim of this study is to define standards for the use of near-infrared autofluorescence (NIRAF)-based overlay imaging via EleVision IR (Medtronic, Dublin, Ireland) and to evaluate its clinical applicability.

PATIENTS AND METHODS

This prospective study included 189 patients who had undergone open thyroid and/or parathyroid surgery and in whom EleVision IR was applied to visualize at least one parathyroid gland (PG) between January 2021 and May 2022 in a tertiary referral care center. Whether the PGs were first localized by the surgeon or by overlay imaging was noted. Handling of the device, application time and duration, distance, infrared intensity (IR%), and the angle of each measurement were analyzed. In thyroidectomies, the specimens were subsequently scanned for further PGs. NIRAF patterns and intensities were described.

RESULTS

Overall, 543 PGs were analyzed in 158 (83.6%) surgeries of thyroid glands (TGs) and in 49 (25.9%) surgeries for hyperparathyroidism. In 111 (58.7%) patients, identical numbers of PGs were detected by the surgeon and by overlay imaging. While a larger number of PGs was identified by the surgeon in 48 (25.4%) patients, overlay imaging served to detect more PGs in 30 (15.9%) cases. In four (2.1%) patients, PGs were visualized post-thyroidectomy due to their autofluorescence on the specimen. NIRAF-based overlay imaging was applied to depict the PGs early on after exposure by the surgeon. The ideal distance for the measurement ranged between 8 and 12 cm with an angle of 90° and a mean IR% of 34.5% (± 17.6).

CONCLUSIONS

Considering the standard operating procedures, NIRAF-based overlay imaging can be used as an adjunct tool for intraoperative localization.

Improvement in Central Neck Dissection Quality in Thyroid Cancer by Use of Tissue Autofluorescence

BACKGROUND

Risk of postoperative transient or permanent hypoparathyroidism represents one of the most common complications following total thyroidectomy. This risk increases if a cervical lymphadenectomy procedure must also be performed, as is usually the case in thyroid carcinoma patients. Parathyroid autofluorescence (AF) is a non-invasive method that aids intraoperative identification of parathyroid glands.

METHODS

In this prospective study, 189 patients with papillary thyroid cancer who underwent total thyroidectomy with central neck dissection were included. Patients were randomly allocated to one of two groups: NAF (no AF, surgery was performed without AF) and the AF group (surgery was performed with AF-Fluobeam LX system, Fluoptics, Grenoble, France).

RESULTS

The number of excised lymph nodes was significantly higher in the AF compared to the NAF group, with mean values of 21.3 ± 4.8 and 9.2 ± 4.1, respectively. Furthermore, a significantly higher number of metastatic lymph nodes were observed in the AF group. Transient hypocalcemia recorded significantly lower rates in the AF group with 4.9% compared to 16.8% in the NAF group.

CONCLUSIONS

AF use during total thyroidectomy with central neck dissection for papillary thyroid carcinoma patients, decreased the rate of iatrogenic parathyroid gland lesions, and increased the rate of lymphatic clearance.

Near-infrared fluorescent imaging for parathyroid identification and/or preservation in surgery for primary hyperparathyroidism

Introduction

Near infrared autofluorescence (NIRAF) is a novel intraoperative technology that has shown promising results in the localisation of parathyroid glands (PGs) over the last decade. This study aimed to assess the potential utility of NIRAF in first time surgery for primary hyperparathyroidism (PHPT).

Methods

An observational study over a period of 3 years in patients who underwent surgery for PHPT was designed. Data on the use of NIRAF and fluorescent patterns in different organs (thyroid and parathyroid) and parathyroid pathology (single versus multi-gland disease) were explored. In addition, cure rates and operating times were compared between the NIRAF and no-NIRAF groups to determine the potential value of NIRAF in this cohort.

Results

In 230 patients undergoing first time surgery for PHPT, NIRAF was used in 50 patients. Of these 50 patients, NIRAF was considered to aid parathyroid identification in 9 patients (18%). The overall cure rate at 6 months of follow-up was 96.5% (98% in NIRAF and 96.1% without NIRAF; p=1.0). The median (interquartile range) operating time was longer in the NIRAF arm at 102 minutes (74-120 minutes) compared to the no-NIRAF arm at 75 minutes (75-109 minutes); however, this difference was not statistically significant (p=0.542). Although the median parathyroid to thyroid (P/T) auto-fluorescence (AF) ratio was similar between single gland and multi gland disease (2.5 vs to 2.76; p=1.0), the P/T AF ratio correlated negatively with increasing gland weight (p=0.038).

Conclusion

The use of NIRAF resulted in some potential "surgeon-perceived" benefit but did not lead to improvements in cure rates. The negative correlation between fluorescent intensity and gland weight suggests loss of fluorescence with pathology, which needs further investigation. Further studies on larger cohorts of patients, in depth analysis of fluorescence patterns between normal, adenomatous, and hyperplastic glands and evaluation of user experience are needed. Primary hyperparathyroidism, hyperparathyroidism, autofluorescence, near-infrared fluorescence, parathyroid glands, endocrine, surgery.

TOETVA parathyroid autofluorescence detection: hANDY-i endoscopy attachment

Background

Treatment options for thyroid pathologies have expanded to include scarless and remote access methods such as the transoral endoscopic thyroidectomy vestibular approach (TOETVA). Currently, no standardized methods exist for locating parathyroid glands (PGs) in patients undergoing TOETVA, which can lead to parathyroid injury and subsequent hypocalcemia. This early feasibility study describes and evaluates the hANDY-i endoscopic attachment for detecting PGs in transoral thyroidectomy.

Methods

We used a prototype parathyroid autofluorescence imager (hANDY-i) that was mounted to a 10-mm 0-degree endoscope. The device delivers a split screen view of Red-green-blue (RGB) and near-infrared autofluorescence (NIRAF) which allows for simultaneous anatomical localization and fluorescence visualization of PGs during endoscopic thyroid dissection.

Results

One cadaveric case and two patient cases were included in this study. The endoscopic hANDY-i imaging system successfully visualized PGs during all procedures.

Conclusion

The ability to leverage parathyroid autofluorescence during TOETVA may lead to improved PG localization and preservation. Further human studies are needed to assess its effect on postoperative hypocalcemia and hypoparathyroidism.