Intraoperative localization of the parathyroid glands with indocyanine green and Firefly(R) technology during BABA robotic thyroidectomy

Assessment of ICG fluorescence in identification and preservation of parathyroid glands in thyroid surgeries and correlation with postoperative parathormone and serum calcium levels

INTRODUCTION

Intraoperative parathyroid gland (PG) localization remains challenging during thyroid surgeries, contributing to postoperative hypocalcemia and hypoparathyroidism. This study assessed the efficacy of indocyanine green (ICG) fluorescence in identifying and preserving PGs during thyroid surgeries and its correlation with postoperative outcomes.

MATERIALS AND METHODS

This ambispective observational study included 57 patients undergoing thyroid surgeries using ICG and compared outcomes with 56 historical controls. ICG was administered intravenously in two 5 mg boluses. Parathyroid identification rates, fluorescence intensity, and postoperative calcium and parathormone levels were assessed. Fluorescence intensity was qualitatively scored on a 1-3 scale.

RESULTS

ICG significantly improved PG identification (92.5% vs 69.3% with white light alone). Postoperative hypocalcemia occurred in 22.81% of ICG patients compared to 39.29% in controls (p = 0.045). Hypoparathyroidism rates were 10.53% and 32.14% respectively (p = 0.005). Higher fluorescence intensity (FI) correlated with lower risk of postoperative hypocalcemia (p = 0.026) and combined hypocalcemia and hypoparathyroidism (p = 0.046). Considering both FI 2 and 3 as positive yielded 100% sensitivity and 85.7% accuracy. When only FI 3 was considered positive, sensitivity was 78.4%, specificity was 50%, and accuracy was 69.4%.

CONCLUSION

ICG fluorescence is a safe and effective tool for enhancing PG identification and preservation in thyroid surgeries, significantly reducing postoperative hypocalcemia and hypoparathyroidism. It also helps in confirming the vascularity of the PGs post thyroidectomy. Fluorescence intensity of preserved PGs, rather than quantity, better predicts postoperative outcomes. These findings support the integration of ICG fluorescence imaging and the application of our methodology in thyroid surgeries to improve postoperative results.

Intraoperative image-guidance during robotic surgery: is there clinical evidence of enhanced patient outcomes?

BACKGROUND

To date, the benefit of image guidance during robot-assisted surgery (IGS) is an object of debate. The current study aims to address the quality of the contemporary body of literature concerning IGS in robotic surgery throughout different surgical specialties.

METHODS

A systematic review of all English-language articles on IGS, from January 2013 to March 2023, was conducted using PubMed, Cochrane library's Central, EMBASE, MEDLINE, and Scopus databases. Comparative studies that tested performance of IGS vs control were included for the quantitative synthesis, which addressed outcomes analyzed in at least three studies: operative time, length of stay, blood loss, surgical margins, complications, number of nodal retrievals, metastatic nodes, ischemia time, and renal function loss. Bias-corrected ratio of means (ROM) and bias-corrected odds ratio (OR) compared continuous and dichotomous variables, respectively. Subgroup analyses according to guidance type (i.e., 3D virtual reality vs ultrasound vs near-infrared fluoresce) were performed.

RESULTS

Twenty-nine studies, based on 11 surgical procedures of three specialties (general surgery, gynecology, urology), were included in the quantitative synthesis. IGS was associated with 12% reduction in length of stay (ROM 0.88; p = 0.03) and 13% reduction in blood loss (ROM 0.87; p = 0.03) but did not affect operative time (ROM 1.00; p = 0.9), or complications (OR 0.93; p = 0.4). IGS was associated with an estimated 44% increase in mean number of removed nodes (ROM 1.44; p < 0.001), and a significantly higher rate of metastatic nodal disease (OR 1.82; p < 0.001), as well as a significantly lower rate of positive surgical margins (OR 0.62; p < 0.001). In nephron sparing surgery, IGS significantly decreased renal function loss (ROM 0.37; p = 0.002).

CONCLUSIONS

Robot-assisted surgery benefits from image guidance, especially in terms of pathologic outcomes, namely higher detection of metastatic nodes and lower surgical margins. Moreover, IGS enhances renal function preservation and lowers surgical blood loss.

Current and Future of Robotic Surgery in Thyroid Cancer Treatment

Thyroid cancer is among the most common endocrine malignancies, necessitating effective surgical interventions. Traditional open cervicotomy has long been the standard approach for thyroidectomy. However, the advent of robotic surgery has introduced new possibilities for minimally invasive procedures with benefits in terms of cosmetic outcomes, enhanced precision, comparable complication rates, and reduced recovery time. This study mainly reviewed the most widely used and well-known robotic thyroidectomy approaches: the transaxillary approach, the bilateral axillo-breast approach, and the transoral approach. This review examines the current status and future potential of robotic surgery in thyroid cancer treatment, comparing its efficacy, safety, and outcomes with those of conventional open cervicotomy. Challenges such as a longer operative time and higher costs exist. Future directions include technological advancements, tele-surgery, single-port surgery, and the integration of artificial intelligence. Robotic surgery holds promise in optimizing patient outcomes in thyroid cancer treatment.

Comparison of indocyanine green angiography vs intraoperative parathyroid hormone in early prediction of risk of post-thyroidectomy hypocalcemia: a prospective cohort study

Introduction

Indocyanine green (ICG) angiography is the 'real-time intraoperative imaging' technique used to reduce the chances of hypoparathyroidism in post-thyroidectomy patients. In our study, the authors predicted the risk of early post-thyroidectomy hypocalcemia by intraoperative evaluation of parathyroid gland perfusion by ICG angiography.

Materials and methods

In patients who underwent total thyroidectomy, ICG angiography was done using the SPY PHI imaging system (Stryker). Post-thyroid specimen removal, scoring of parathyroids was done in spy contrast mode. All 4 or <4 visualized parathyroids were scored for vascularity with the highest score of 8. Serum ionized calcium was done 6 h postsurgery and on the morning and evening of postoperative days 1 and 2. Calcium supplements were given to only those who developed clinical or severe biochemical hypocalcemia.

Results

Out of 60, postoperative hypocalcemia was noted in 41 patients. Total ICG score ≤5 was seen in 34 patients, out of which 28 developed postoperative hypocalcemia showing PPV 82.3% and diagnostic accuracy of 68.3% while iPTH (4.28 pmol/l) showed PPV 76.7 and diagnostic accuracy 70 %. In eight patients, none of the glands was scored as 2 (White) and all these patients developed hypocalcemia requiring calcium infusion.

Conclusion

The absence of visualization of at least 1 well-perfused (score 2) gland on ICG angiography is highly predictive of hypocalcemia and the majority of patients with total ICG score ≤5 developed hypocalcemia in the immediate postoperative period. ICG is a good predictor of the absence of hypoparathyroidism after thyroidectomy and is comparable to iPTH in the prediction of post-thyroidectomy hypocalcemia.

Intraoperative prevention of postoperative hypoparathyroidism

Objective

More than 30,000 thyroid surgeries are performed annually in the Russian Federation. The surgeries are relatively safe because of the prevention methods for postoperative complications. Currently, there is no single effective method of postoperative hypoparathyroidism prevention. This complication is frequently reported and may be health and life-threatening.

Aim

We aimed to estimate the effectiveness of the intraoperative ICG-angiography and intrathyroid injection of Brilliant Green for the prevention of postoperative hypoparathyroidism.

Material and methods

One hundred and forty-three thyroidectomies were performed. Patients were divided into three groups: intraoperative angiography was used in 24 cases; Brilliant Green was injected in 58 cases to identify parathyroid glands; the visual estimation of the parathyroid preservation was used in 61 cases. Calcium level was measured in all patients before and after surgery.

Results

Calcium level in the serum before and after surgery was 2.37±0.14 and 2.27±0.17 in Group 1, 2.38±0.16 and 2.21±0.16 in Group 2, and 2.39±0.17 and 2.18±0.19 in Group 3. Postoperative hypocalcemia was more prominent in the group with the visually estimated PTG than in the two other groups. The differences in postoperative calcium levels in Groups 1 and 3 were statistically different. Pre- and postoperative Parathormone levels were 6.2±0.4 in Group 1, 5.6±0.57 in Group 2, and 3.5±0.32 in Group 3. Postoperative levels significantly differed in Groups 1 and 3 (p<0.01) and in Groups 2 and 3 (p<0.05).

Conclusions

ICG-angiography and intrathyroid injection of the Brilliant Green are safe methods of identification and sparing of the parathyroid glands. The severity of hypocalcemia and hypoparathormonemia in Group 3 shows the necessity of finding new methods in endocrine surgery to improve patient outcomes.

Soft tissue surgical robot for minimally invasive surgery: a review

Purpose

The current state of soft tissue surgery robots is surveyed, and the key technologies underlying their success are analyzed. State-of-the-art technologies are introduced, and future directions are discussed.

Methods

Relevant literature is explored, analyzed, and summarized.

Results

Soft tissue surgical robots had rapidly spread in the field of laparoscopic surgery based on the multi-degree-of-freedom movement of intra-abdominal surgical tools and stereoscopic imaging that are not possible in conventional surgery. The three key technologies that have made surgical robots successful are wire-driven mechanisms for multi-degree-of-freedom movement, master devices for intuitive remote control, and stereoscopic imaging technology. Recently, human-robot interaction technologies have been applied to develop user interfaces such as vision assistance and haptic feedback, and research on autonomous surgery has begun.

Conclusion

Robotic surgery not only replaces conventional laparoscopic surgery but also allows for complex surgeries that are not possible with laparoscopic surgery. On the other hand, it is also criticized for its high cost and lack of clinical superiority or patient benefit compared to conventional laparoscopic surgery. As various robots compete in the market, the cost of surgical robots is expected to decrease. Surgical robots are expected to continue to evolve in the future due to the need to reduce the workload of medical staff and improve the level of care demanded by patients.

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.

Robot-Assisted Parathyroidectomy Using Indocyanine Green (ICG) Fluorescence in Primary Hyperparathyroidism

Background and Objectives: Surgical treatment for primary hyperparathyroidism (PHPT) has evolved from bilateral exploration through a long transcervical incision to focused parathyroidectomy with a minimal incision above the pathologic gland. Recently, endoscopic or robot-assisted parathyroid surgery without direct neck incision has been introduced. The aim of this study was to investigate the effectiveness of indocyanine green (ICG) fluorescence as a new method for the visual identification of abnormal hyperfunctioning parathyroid glands in robot-assisted parathyroidectomy using FireflyTM technology. We also aimed to conduct a comparative analysis between robot-assisted parathyroidectomy and conventional focused parathyroidectomy in order to identify clinical differences between the two surgical approaches. Materials and Methods: A total of 37 patients with PHPT underwent parathyroidectomy at a single university hospital between September 2018 and December 2022. Thirty-one patients underwent open focused parathyroidectomy (open group), and six patients underwent robot-assisted parathyroidectomy (robot group). Pre-operative localization via parathyroid SPECT-CT and an intraoperative parathyroid hormone (IOPTH) assay were used to successfully remove the pathologic parathyroid in both groups. ICG was administered only in the robot group. Results: Pathologic parathyroid showed a persistent fluorescence pattern under near-infrared vision. After the removal of the fluorescent parathyroid gland, IOPTH was normalized in all six patients in the robot group. However, the open group showed shorter hospital stays (1.8 ± 1.2 vs. 3.0 ± 0.0 days, p < 0.001) and shorter operation times (91.1 ± 69.1 vs. 152.5 ± 23.6 min, p = 0.001) than the robot group. After 6 months of surgery, PTH, calcium, and ionized calcium levels were all normalized without significant differences between the groups. Conclusions: Robot-assisted parathyroidectomy using ICG is helpful for the visual identification of the pathologic parathyroid gland. The advantage of robot parathyroidectomy is a better cosmetic outcome. However, it still does not show better clinical outcomes than conventional open focused parathyroidectomy.

Converting a probe-based fluorescence system into an easy-to-use adjunct for the detection of parathyroid glands accidentally resected intraoperatively

PURPOSE

The reported threshold of a near-infrared fluorescence detection probe (FDP) for judging parathyroid glands (PGs) is based on the autofluorescence intensity relative to other non-PG tissues, making it unreliable when not enough reference tissues are measured. We aim to convert FDP into a more convenient tool for identifying accidentally resected PGs by quantitative measurements of autofluorescence in resected tissues.

METHODS

It was a prospective study approved by the Institutional Review Board. The research was divided into two stages: (1) In order to calibrate the novel FDP system, autofluorescence intensity of different in / ex vivo tissues was measured and the optimal threshold was obtained using receiver operating characteristic (ROC) curve. (2) To further validate the effectiveness of the new system, detection rates of incidental resected PGs by pathology in the control group and by FDP in the experimental group were compared.

RESULTS

Autofluorescence of PGs was significantly higher than that of non-PG tissue (43 patients, Mann-Whitney U test, p < 0.0001). An optimal threshold of sensitivity / specificity (78.8% and 85.1%) for discriminating PGs was obtained. The detection rates of experimental group (20 patients) and control group (33 patients) are 5.0% and 6.1% respectively (one-tailed Fisher's exact test, p = 0.6837), indicating the novel FDP system can achieve a similar proportion of PG detection compared with pathological examinations.

CONCLUSIONS

The novel FDP system can be used as an easy-to-use adjunct for detecting PG accidentally resected intraoperatively before the tissues are sent for frozen sections during thyroidectomy surgeries.

TRIAL REGISTRATION

Registration number: ChiCTR2200057957.

Modern Surgical Techniques of Thyroidectomy and Advances in the Prevention and Treatment of Perioperative Complications

Thyroid cancer is the most common cancer of the endocrine system, and, in recent years, there has been a phenomenon of overdiagnosis followed by subsequent overtreatment. This results in an increasing number of thyroidectomy complications being faced in clinical practice. In this paper, we present the current state of knowledge and the latest findings in the fields of modern surgical techniques, thermal ablation, the identification and assessment of parathyroid function, recurrent laryngeal nerve monitoring and treatment and perioperative bleeding. We reviewed 485 papers, from which we selected 125 papers that are the most relevant. The main merit of this article is its comprehensive view of the subject under discussion-both general, concerning the selection of the appropriate method of surgery, and particular, concerning the selection of the appropriate method of prevention or treatment of selected perioperative complications.

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.

Emerging Imaging Technologies for Parathyroid Gland Identification and Vascular Assessment in Thyroid Surgery: A Review From the American Head and Neck Society Endocrine Surgery Section

Importance

Identification and preservation of parathyroid glands (PGs) remain challenging despite advances in surgical techniques. Considerable morbidity and even mortality result from hypoparathyroidism caused by devascularization or inadvertent removal of PGs. Emerging imaging technologies hold promise to improve identification and preservation of PGs during thyroid surgery.

Observation

This narrative review (1) comprehensively reviews PG identification and vascular assessment using near-infrared autofluorescence (NIRAF)-both label free and in combination with indocyanine green-based on a comprehensive literature review and (2) offers a manual for possible implementation these emerging technologies in thyroid surgery.

Conclusions and Relevance

Emerging technologies hold promise to improve PG identification and preservation during thyroidectomy. Future research should address variables affecting the degree of fluorescence in NIRAF, standardization of signal quantification, definitions and standardization of parameters of indocyanine green injection that correlate with postoperative PG function, the financial effect of these emerging technologies on near-term and longer-term costs, the adoption learning curve and effect on surgical training, and long-term outcomes of key quality metrics in adequately powered randomized clinical trials evaluating PG preservation.

A Time Trend Analysis of 5,000 Robotic Thyroidectomies via Bilateral Axillo-Breast Approach

BACKGROUND

This study aimed to investigate the time trends of surgical outcomes in patients who underwent bilateral axillo-breast approach robotic thyroidectomy (BABA RT) over the last 14 years.

METHODS

From February 2008 to September 2021, we conducted a retrospective medical chart review of 5,011 consecutive patients who underwent BABA RT at three Seoul National University-affiliated hospitals. The patients were divided into three groups based on the main model of the da Vinci robotic surgical system to evaluate trends in surgical treatment strategies and outcomes after BABA RT.

RESULTS

Of the 5,011 patients (4,706 malignant and 305 benign), the most common histological subtype was papillary thyroid carcinoma (n = 4,584; 97.4%). The mean tumor size significantly increased from 0.8 cm to 1.2 cm (p < 0.05). The mean numbers of metastatic and harvested lymph nodes from the central neck dissection and the lateral neck dissection showed a significant difference and tendency to increase (from 0.9 to 1.6, 4.7 to 6.2, p < 0.05, and from 0.6 to 3.9, 5.3 to 17.9, p < 0.05), respectively, throughout the study period. Permanent hypoparathyroidism decreased from 3.4 to 2.9%. The rate of transient and permanent vocal cord palsy decreased from 15.2 to 2.7% and from 0.7 to 0.2%, respectively.

CONCLUSION

With advancements in robotic surgical systems and improvements in the BABA RT technique, surgical indications have expanded to include more advanced thyroid diseases, and surgical outcomes have improved over the last 14 years.

[Indocyanine green fluorescence angiography in transoral endoscopic thyroidectomy for papillary thyroid cancer]

OBJECTIVE

To evaluate the effectiveness of ICG angiography in patients with papillary thyroid cancer (PTC) undergoing transoral endoscopic thyroidectomy (TOETVA) and selective neck dissection (level VI).

MATERIAL AND METHODS

A retrospective analysis included 20 patients with PTC who underwent TOETVA with selective neck dissection (level VI) between September and December 2022. ICG was administered intravenously (5 mg ´ 3 times). We analyzed parathyroid glands by visual examination and ICG angiography. Fluorescence of all glands was assessed.

RESULTS

Twenty patients underwent ICG angiography during TOETVA. A total of 68 parathyroid glands were identified. Only 76.5% (52/68) of parathyroid glands were identified at initial visual examination. ICG angiography additionally localized 12 glands that improved detection to 94.1% (64/68). At least one well-vascularized parathyroid gland was demonstrated by ICG angiography in 16 patients. In all these patients, serum parathyroid hormone was normal in 1 and 10 days after surgery. Two out of four patients who failed to identify a well-vascularized parathyroid gland developed transient hypoparathyroidism. There were no intraoperative and postoperative complications associated with ICG angiography.

CONCLUSION

ICG angiography was simple, safe and effective for better identification and preservation of parathyroid glands in patients with PTC undergoing TOETVA. This method was valuable for assessing the viability and function of parathyroid glands and predicting postoperative hypocalcemia.

Safe thyroid surgery: comparison effectiveness of ICG angiography and intrathyroidal brilliant green injection for the prevention of postoperative hypoparathyroidism

BACKGROUND: More than 30,000 surgical interventions on the thyroid gland are performed annually in the Russian Federation. Surgeons are developing methods for the prevention of various postoperative complications, and therefore operations on this organ are considered relatively safe. Currently, there is no unequivocal effective method to prevent postoperative hypoparathyroidism. This complication is often recorded and can threaten the life and health of the patient, which is contrary to the concept of safe surgery.

AIM: To evaluate the effectiveness of intraoperative ICG angiography and intrathyroidal injection of brilliant green for the prevention of postoperative hypoparathyroidism.

MATERIALS AND METHODS: 143 thyroidectomies were performed. The patients were divided into 3 groups: intraoperative angiography was used in 24 cases, brilliant green was injected to identify the parathyroid glands in 58 cases, visual assessment of the preservation of the parathyroid glands was used in 61 case. Calcium levels were measured in all patients included in the study before and after surgery.

RESULTS: Serum calcium levels in the pre- and postoperative period: 2.37±0.14 and 2.27±0.17 in group 1, and 2.38±0.16 and 2.21±0.16 in group 2, 2.39±0.17 and 2.18±0.19 in group 3. Hypocalcemia in the postoperative period was significantly higher in the group with a visual assessment of the parathyroid glands relative to the first two groups. Differences between calcium levels in the postoperative period in groups 2 and 3 were significant with a probability of more than 99% (p<0.01). Significant differences (≥95%) in calcium levels in the postoperative period between groups 1 and 2 (p < 0.05) were obtained. Serum PTH levels in the postoperative period: 6,2±0,4 in group 1, 5,6±0,57 in group 2, 3,5±0,32 in group 3. Differences between PTH levels in the postoperative period in groups 1 and 3 were significant with a probability of more than 99% (p<0.01). Significant differences (≥95%) in PTH levels in the postoperative period between groups 2 and 3 (p < 0.05) were obtained.

CONCLUSION: ICG angiography and brilliant green intrathyroidal injection are safe methods for identifying and preserving the parathyroid glands. The high level of hypocalcemia in group 3 indicates the need to search for new techniques in endocrine surgery in order to improve the safety of patients undergoing surgical treatment of thyroid pathology.

Near-infrared fluorescent imaging techniques for the detection and preservation of parathyroid glands during endocrine surgery

Objectives

In over 30% of all thyroid surgeries, complications arise from transient and definitive hypoparathyroidism, underscoring the need for real-time identification and preservation of parathyroid glands (PGs). Here, we evaluate the promising intraoperative optical technologies available for the identification, preservation, and functional assessment of PGs to enhance endocrine surgery.

Methods

We performed a review of the literature to identify published studies on fluorescence imaging in thyroid and parathyroid surgery.

Results

Fluorescence imaging is a well-demonstrated approach for both in vivo and in vitro localization of specific cells or tissues, and is gaining popularity as a technique to detect PGs during endocrine surgery. Autofluorescence (AF) imaging and indocyanine green (ICG) angiography are two emerging optical techniques to improve outcomes in thyroid and parathyroid surgeries. Near-infrared-guided technology has significantly contributed to the localization of PGs, through the detection of glandular AF. Perfusion through the PGs can be visualized with ICG, which can also reveal the blood supply after dissection.

Conclusions

Near infrared AF and ICG angiography, providing a valuable spatial and anatomical information, can decrease the incidence of complications in thyroid surgery.

Intraoperative assessment of parathyroid perfusion using indocyanine green angiography in robotic thyroidectomy

In recent da Vinci robot systems (Intuitive Surgical), near-infrared fluorescence imaging (Firefly technology) has been used. With this technique, it is possible for surgeons to see important structures well beyond the limits of their eyes; hence, surgeons can safely operate and make critical decisions accurately using image-guided surgery. Because parathyroid glands (PTGs) are small and embedded in the surrounding tissues, such as lymph nodes and fat, it is often very hard for surgeons to identify PTGs. To preserve PTGs well, the surgeon must be able to accurately identify PTGs, preserve the vasculature surrounding, and maintain the perfusion to PTGs. Herein, we report an assessment of PTG perfusion using indocyanine green angiography in transoral robotic thyroidectomy.

A coaxial excitation, dual-red-green-blue/near-infrared paired imaging system toward computer-aided detection of parathyroid glands in situ and ex vivo

Early and precise detection of parathyroid glands (PGs) is a challenging problem in thyroidectomy due to their small size and similar appearance to surrounding tissues. Near-infrared autofluorescence (NIRAF) has stimulated interest as a method to localize PGs. However, high incidence of false positives for PGs has been reported with this technique. We introduce a prototype equipped with a coaxial excitation light (785 nm) and a dual-sensor to address the issue of false positives with the NIRAF technique. We test the clinical feasibility of our prototype in situ and ex vivo using sterile drapes on 10 human subjects. Video data (1287 images) of detected PGs were collected to train, validate and compare the performance for PG detection. We achieved a mean average precision of 94.7% and a 19.5-millisecond processing time/detection. This feasibility study supports the effectiveness of the optical design and may open new doors for a deep learning-based PG detection method.

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.

Remote Access Thyroid Surgery: A Review of Literature

Since the first description of endoscopic thyroid lobectomy in 1997, a variety of techniques have been developed to avoid the visible cervical scar conventionally been associated with thyroidectomy. These "remote access" approaches, which typically use either endoscopic or robotic instrumentation, have successfully avoided the anterior neck scar, which has a measurable impact on the patient's quality of life (Graves and Suh Surgery 168(5):845-850, 2020; Sakorafas World J Surg 34(8):1793-1804, 2010). The main advantage of these techniques is better cosmesis compared to conventional transcervical approaches (Graves and Suh Surgery 168(5):845-850, 2020) However, these techniques have failed to gain widespread acceptance in the surgical community because of the technical challenges, scepticism about oncological safety and cost factors. This review presents an overview of the various methods of remote access thyroid surgery (RATS) and also evaluates the selection criteria, oncological efficacy, training requirements and key advantages of this technique.

A pilot feasibility study to assess vascularity and perfusion of parathyroid glands using a portable hand-held imager

OBJECTIVES

Intraoperative localization and preservation of parathyroid glands (PGs) are challenging during thyroid surgery. A new noninvasive technique of combined near-infrared PG autofluorescence detection and dye-free imaging angiography that allows intraoperative feedback has recently been introduced. The objective of this study was to evaluate this technique in real-time.

MATERIALS AND METHODS

A pilot feasibility study of a portable imaging device in four patients who underwent either thyroid lobectomy or total thyroidectomy is presented. PG autofluorescence and vascularity/tissue perfusion were monitored using a real-time screen display during the surgical procedure.

RESULTS

Three lobectomies and one total thyroidectomy were performed. Among the nine PGs identified by the operating surgeon, eight PGs were confirmed using the autofluorescence device. Each PG was successfully determined to be either well-perfused or devascularized, and devascularized PGs were autotransplanted.

CONCLUSIONS

The preliminary results suggest that the combination of PG autofluorescence detection and dye-free angiography can potentially be used to assess PG function. With further validation studies, the effectiveness of this technique in clinical practice can be further delineated.

Application of Indocyanine Green Angiography in Bilateral Axillo-Breast Approach Robotic Thyroidectomy for Papillary Thyroid Cancer

BACKGROUND

Indocyanine green angiography (ICGA) has been used to identify and preserve the parathyroid glands (PGs), and to evaluate PGs viability and function during thyroid surgery. However, evidence on the utilization of IGCA in thyroid cancer and robotic surgery is lacking. The efficacy of IGCA remains to be evaluated in PTC patients undergoing bilateral axillo-breast approach robotic thyroidectomy (BABA RT) and central neck dissection (CND).

METHODS

From March 2020 to August 2021, 81 papillary thyroid cancer (PTC) patients receiving total thyroidectomy and CND were enrolled in this retrospective analysis. An intravenous bolus of 7.5 mg ICG was administrated three times in the ICGA group (n=34). Medical records were reviewed and analyzed, including the baseline characteristics, surgical parameters, PGs-related parameters, and perioperative PTH and calcium levels.

RESULTS

The mean number of total identified PGs and preserved PGs were significantly more in the ICG group than in the control group (3.74 ± 0.45 vs. 3.15 ± 0.55, P<0.001; 3.12 ± 0.64 vs. 2.74 ± 0.57, P=0.007, respectively), as were PTH and calcium levels on POD 1 (23.16 ± 18.32 vs. 6.06 ± 7.74, P=0.039; 2.13 ± 0.11 vs. 2.08 ± 0.08, P=0.024, respectively). While there were no differences in PTH levels on POD 30. Additionally, patients with at least one well vascularized PG had higher ioPTH 3 and PTH on POD 1, which significantly suggested the absence of postoperative hypocalcemia. Although not statistically significant, ICGA seemed superior to relative ioPTH decline and ioPTH 3 in predicting postoperative hypocalcemia.

CONCLUSION

In PTC patients undergoing BABA RT and CND, ICGA is a simple, safe, effective, and cost-effective tool in better identification and preservation of PGs as well as evaluation of PGs viability and function, with the potential to preserve more PGs, guide more appropriate autotransplantation, and accurately predict postoperative hypocalcemia.

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

BACKGROUND

To evaluate the diagnostic accuracies of indocyanine green (ICG) fluorescence for identifying parathyroid glands during surgery and predicting the postoperative function.

METHODS

From six databases, 21 studies were finally included in the study. True-positive, true-negative, false-positive, and false-negative data were extracted for the analysis. The quality of each study was analyzed using the QUADAS-2 tool.

RESULTS

The sensitivity of ICG-based parathyroid gland identification was 0.9380 (95% CI [0.9003, 0.9621]). The diagnostic odds ratio for ICG-based prediction of parathyroid gland function was 54.5652 [13.2059, 225.4570]. The area under the summary receiver operating characteristic curve was 0.909. Fluorescence intensity-based prediction presented higher diagnostic accuracy than that of score-based prediction. The incidence of postoperative hypoparathyroidism was higher in the group with a zero ICG score compared to the high scored group.

CONCLUSIONS

Identification of parathyroid gland and prediction of postoperative function using ICG are valuable to patients undergoing thyroidectomy or parathyroidectomy.

A narrative review of fluorescence imaging in robotic-assisted surgery

Objective

In this review, we provide examples of applications of fluorescence imaging in urologic, gynecologic, general, and endocrine surgeries.

Background

While robotic-assisted surgery has helped increase the availability of minimally invasive procedures across surgical specialties, there remains an opportunity to reduce adverse events associated with open, laparoscopic, and robotic-assisted methods. In 2011, fluorescence imaging was introduced as an option to the da Vinci Surgical System, and has been standard equipment since 2014. Without interfering with surgical workflow, this fluorescence technology named Firefly^® allows for acquisition and display of near-infrared fluorescent signals that are co-registered with white light endoscopic images. As a result, robotic surgeons of all specialties have been able to explore the clinical utility of fluorescence guided surgery.

Methods

Literature searches were performed using the PubMed and MEDLINE databases using the keywords "robotic-assisted fluorescence surgery", "ICG robotic surgery", and "fluorescence guided surgery" covering the years 2011-2020.

Conclusions

Real-time intraoperative fluorescence guidance has shown great potential in helping guide surgeons in both simple and complex surgical interventions. Indocyanine green is one of the most widely-used imaging agents in fluorescence guided surgery, and other targeted, near-infrared imaging agents are in various stages of development. Fluorescence is becoming a reliable tool that can help surgeons in their decision-making process in some specialties, while explorations continue in others.

Near-Infrared Autofluorescence Imaging May Reduce Temporary Hypoparathyroidism in Patients Undergoing Total Thyroidectomy and Central Neck Dissection

Background: Near-infrared autofluorescence (NIRAF) imaging is known to reduce the incidence of post-thyroidectomy hypocalcemia. However, there are no studies on how much NIRAF imaging affects the serum parathyroid hormone (PTH) level after surgery. We investigated the changes of the serum PTH level and ionized calcium (iCa.) in patients undergoing total thyroidectomy with central neck dissection (CND). Materials and Methods: This retrospective study with historical control enrolled 542 patients who underwent total thyroidectomy with CND. Patients were divided into two groups: the NIRAF group (261 patients) and the control group (281 patients). PTH and iCa. levels were measured at the hospital stay, 1, 3, and 6 months after surgery. In addition, the number of identified parathyroid glands (PGs), autotransplanted PGs, and the inadvertent resection rate of PGs was evaluated. Results: The incidence of postoperative hypoparathyroidism (PTH <15 pg/mL) was significantly lower in the NIRAF group during the hospitalization (88 patients: 33.7% vs. 131 patients: 46.6%; p = 0.002) and at 1 month postoperatively (23 patients: 8.8% vs. 53 patients: 18.9%; p = 0.001). There was no difference in the permanent hypoparathyroidism rate (6 months after surgery) between the NIRAF group and the control group (4.2% vs. 4.6%; p = 0.816). There was no difference in the incidence of hypocalcemia (iCa. <1.09 mmol/L) (during hospitalization: 6.5% vs. 10.0%; 1 month: 2.3% vs. 2.5%; 3 months: 0.8% vs. 0.7%; 6 months after surgery: 1.1% vs. 1.1%) between the two groups. The number of inadvertently resected PGs was significantly lower in the NIRAF group (18:6.9% vs. 36:12.8%; p = 0.021). Conclusions: These results suggest that NIRAF imaging may reduce temporary hypoparathyroidism and the risk of inadvertent resection of PGs in patients undergoing total thyroidectomy with CND.

Indocyanine Green Angiography for Parathyroid Gland Evaluation during Transoral Endoscopic Thyroidectomy

Indocyanine green (ICG) angiography, a real-time intraoperative imaging technique, is associated with better parathyroid identification and functional evaluation during open thyroidectomy. However, the benefits of ICG fluorescence imaging application in transoral endoscopic thyroidectomy are not well-documented. Consecutive patients who underwent transoral endoscopic thyroidectomy were retrospectively reviewed. Parathyroid glands were assessed with visual inspection followed by ICG angiography. The fluorescence intensity of all parathyroid glands was recorded. In total, 158 parathyroid glands from 60 patients (41 underwent lobectomy and 19 underwent total thyroidectomy) were eligible for evaluation. A total of 135 parathyroid glands (85.4%) were identified, including nine glands (5.7%) that were solely localized because of ICG angiography. Incidental parathyroidectomy occurred in 12 patients with predominant inferior gland (83.3%) and associated with central neck dissection (66.7%). Among patients receiving total thyroidectomy, patients who retained at least one well-perfused parathyroid gland had higher parathyroid hormone (PTH) level and were less likely to develop hypoparathyroidism on postoperative day one than those without any well-perfused ICG-enhanced parathyroid gland (p = 0.038). In addition, the duration of calcium supplementation to maintain normocalcemia was also shorter. ICG angiography is a feasible adjunct procedure for parathyroid identification and postoperative functional prediction in transoral endoscopic thyroidectomy.

Rapid intraoperative perfusion assessment of parathyroid adenomas with ICG using a wide-field portable hand-held fluorescence imaging system

BACKGROUND

Fluorescence angiography (FA) using indocyanine green dye (ICG) has recently been introduced for real-time identification of parathyroid adenomas. However, time to peak fluorescence has not yet been critically evaluated.

METHODS

This was a retrospective review of parathyroidectomies with ICG FA over a one-year period.

RESULTS

There were 66 patients with average age of 64 years. The average time to initial fluorescence was 26.7 s and to peak fluorescence was 38.0 s. The time to saline flush administration significantly correlated with times to initial and peak fluorescence (p < .0001). The rate of in-situ fluorescence was 97%. The rates of suspected adenoma detection were 69% for sestamibi scan, 71% for ultrasound, and 96% for CT scan. Imaging was discordant in 13 cases (20%), with the adenoma located on the opposite side of the neck in 4 cases.

CONCLUSIONS

ICG FA is a rapid and effective adjunct for the intraoperative identification of parathyroid adenomas.

Indocyanine green fluorescence imaging-guided laparoscopic right posterior hepatectomy

BACKGROUND

Laparoscopic right posterior hepatectomy is considered difficult on the basis of the surgery difficulty scoring system. In this study, we evaluated the safety and effectiveness of the technical application of indocyanine green (ICG) fluorescence imaging-guided laparoscopic right posterior hepatectomy.

METHODS

Twenty-six patients who underwent ICG fluorescence imaging-guided laparoscopic right posterior hepatectomy at Hepatobiliary and Pancreatic Surgery Department of Zhongnan Hospital, Wuhan University, from June 2018 to December 2019, were included. The influence of patient position, trocar placement, hepatic inflow occlusion, central venous pressure (CVP), and the ICG fluorescence imaging-guided method were analyzed.

RESULTS

In 17 patients, the left lateral position was maintained when the main tumor was in the S7, and in the remaining nine patients, the supine position was maintained with the right side of the body raised when the main tumor was in the S6. Ten patients who underwent preoperative injection of ICG were successfully developed for nonanatomical hepatectomy. Sixteen patients received intraoperative ICG injection for anatomical hepatectomy (2 cases had positive imaging findings, 14 cases had negative imaging findings, and 2 cases had failed imaging findings). All patients underwent the Pringle maneuver during the procedure. Four patients were preset with subhepatic vena cava blocking and one patient with suprahepatic inferior vena cava blocking. CVP was controlled at 3.00 ± 0.63 (mean ± SD) cmH₂O. The operative time was 216.14 ± 52.05 min, and the bleeding volume was 128.57 ± 75.55 ml. Four patients had Clavien-Dindo level I complications, and one had level III complications. Postoperative hospitalization duration was 6.19 ± 1.40 days. There were 14 patients with hepatocellular carcinoma, 9 with metastatic liver malignancies, 2 with hepatic hemangioma, 1 with focal nodular hyperplasia of the liver, and 10 with hepatitis B liver cirrhosis.

CONCLUSIONS

ICG fluorescence imaging guidance could be helpful for the safe implementation of laparoscopic right posterior hepatectomy.

Review of successful pathways for regulatory approvals in open-field fluorescence-guided surgery

SIGNIFICANCE

The modern use of fluorescence in surgery came iteratively through new devices and pre-existing imaging agents, with indications that were paved via regulatory approvals and device clearances. These events led to a growing set of surgery subspecialty uses.

AIM

This article outlines the key milestones that initiated commercially marketed systems and agents by highlighting temporal sequences and strategic decisions between them, with the goal of helping to inform future successes.

APPROACH

A review of successful regulatory approvals and the sequences between them was completed for companies that achieved US Food and Drug Administration (FDA) premarket approval or new drug approvals (NDAs) or device clearances in the fields of fluorescent imaging agents, open surgery imaging devices, and their approved medical indications.

RESULTS

Angiography agents, indocyanine green and fluorescein, were approved for human use as absorbing dyes, and this use in retinal imaging was the precursor to lateral translation into tissue perfusion imaging in the last two decades with a growing number of devices. Many FDA cleared devices for open fluorescence-guided surgery used the predicate created by the SPY SP2000 system. This first system was 510(k) cleared for angiography imaging with a unique split predicate from x-ray imaging of vasculature and retinal fluorescence angiography. Since that time, the lateral spread of open surgery devices being cleared for new indications has been occurring with a growth of adoption in surgical subspecialties. Growth into new surgical subspecialties has been achieved by leveraging different NDAs and clearances between indications, such that medical uses have broadened over time.

CONCLUSIONS

Key decisions made by developers to advance specific device clearances and NDAs have been based upon existing optical fluorescent agents. The historical lessons and regulatory trends in newer indications and contrast agents can help the field evolve via successful investment in new systems and applications.

Novel techniques for intraoperative parathyroid gland identification: a comprehensive review

INTRODUCTION

The parathyroid glands (PGs) are critical for calcium regulation and homeostasis. The preservation of PGs during neck surgery is crucial to avoid postoperative hypoparathyroidism. There are no existing guidelines for intraoperative PG identification, and the current approach relies heavily on the experience of the operating surgeon. A technique that accurately and rapidly identifies PGs would represent a useful intraoperative adjunct.

AREAS COVERED

This review aims to assess common dye and fluorescence-based PG imaging techniques and examine their utility for intraoperative PG identification. A literature search of published data on methylene blue (MB), indocyanine green (ICG) angiography, near-infrared autofluorescence (NIRAF), and the PGs between 1971 and 2020 was conducted on PubMed.

EXPERT OPINION

NIRAF and near-infrared (NIR) parathyroid angiography have emerged as promising and reliable techniques for intraoperative PG identification. NIRAF may aid with real-time identification of both normal and diseased PGs and reduce the risk of postoperative complications such as hypocalcemia. Further large prospective multicenter studies should be conducted in thyroid and parathyroid surgical patient populations to confirm the clinical efficacy of these intraoperative NIR-based PG detection techniques.

Indocyanine green fluorescence angiography-guided transoral endoscopic thyroidectomy and parathyroidectomy: First clinical report

BACKGROUND

Indocyanine green fluorescence (ICG) angiography has been used for many purposes including as part of a focused parathyroidectomy technique. Concomitant fluorescence of thyroid tissue may cause challenges defining parathyroid tissue during surgery, since ICG is not a selective fluorescent agent. On the other hand, cosmesis is still a big problem for patients due to the visible neck scars produced by the standard surgical technique. In this study, we described a novel technique to solve both these handicaps.

MATERIALS AND METHODS

Seven patients who underwent ICG fluorescence angiography-guided transoral endoscopic thyroidectomy and parathyroidectomy vestibular approach between February 2018 and July 2019 were included. Serum parathyroid hormone (PTH) levels were measured intraoperatively and on postoperative day 1. Fluorescent images were confirmed with intraoperative quick-PTH levels.

RESULTS

All operations were done successfully without conversion to open surgery. Intense and isolated parathyroid fluorescent images were achieved in all operations. All patients had a 50 % decrease between the baseline and final quick-PTH levels and the final quick-PTH levels were in the normal range in all. One of 7 patients had epistaxis due to nasotracheal intubation. One of 7 patients had seroma on post-operative day 5. None of patients had mental nerve injury, permanent hypocalcemia and temporary or permanent recurrent laryngeal nerve injury.

CONCLUSION

ICG-guided transoral endoscopic thyroid and parathyroid surgery can be used in select patients to increase operative success in focused parathyroidectomy with excellent cosmetic outcome also noted.

Do Near-Infrared Intra-Operative Findings Obtained Using Indocyanine Green Correlate with Post-Thyroidectomy Parathyroid Function? the Icgpredict Study

OBJECTIVE

Postoperative hypoparathyroidism (hypoPT) still remains a significant complication after thyroidectomy. Intra-operative imaging modalities, such as near-infrared fluorescence using indocyanine green (ICG), may assist in identifying and preserving the parathyroid glands (PGs). The purpose of this study was to test the association between the intra-operative ICG staining scoring system and 24-hour postoperative parathyroid hormone (PTH) levels, as well as its capability for intra-operative PG identification.

METHODS

This was a prospective study, recruiting patients scheduled for total thyroidectomy by the same surgical team, from December 2018 to April 2019. Intra-operative angiography was performed after infusion of ICG solution (5 mg). Two minutes later, images were acquired using the near-infrared system.

RESULTS

Sixty patients fulfilled the eligibility criteria. The percentage of temporary postoperative hypoPT (defined as PTH <14 pg/mL) was 11.66%. No association between intra-operative ICG staining score (expressed as the number of PGs scoring <2 per patient) and 24-hour postoperative PTH (r = 0.011; P = .933) or serum calcium concentrations (r = 0.127; P = .335) was observed. There was also no correlation between the location of PGs scoring ≤2 and postoperative PTH (P = .257) or serum calcium levels (P = .950). Moreover, with regard to secondary endpoint, ICG correctly identified PGs in 98.3% of cases. ICG score was not affected by age, gender, duration of operation, or thyroid gland pathology. No allergic reactions attributed to ICG administration were observed.

CONCLUSION

The intra-operative ICG staining scoring system did not predict 24-hour postoperative PTH and serum calcium levels. However, this modality may assist in intra-operative PG identification during a total thyroidectomy.

Could fluorescence-guided surgery be an efficient and sustainable option? A SICE (Italian Society of Endoscopic Surgery) health technology assessment summary

BACKGROUND

Indocyanine green fluorescence vision is an upcoming technology in surgery. It can be used in three ways: angiographic and biliary tree visualization and lymphatic spreading studies. The present paper shows the most outstanding results from an health technology assessment study design, conducted on fluorescence-guided compared with standard vision surgery.

METHODS

A health technology assessment approach was implemented to investigate the economic, social, ethical, and organizational implications related to the adoption of the innovative fluorescence-guided view, with a focus on minimally invasive approach. With the support of a multidisciplinary team, qualitative and quantitative data were collected, by means of literature evidence, validated questionnaires and self-reported interviews, considering the dimensions resulting from the EUnetHTA Core Model.

RESULTS

From a systematic search of literature, we retrieved the following studies: 6 on hepatic, 1 on pancreatic, 4 on biliary, 2 on bariatric, 4 on endocrine, 2 on thoracic, 11 on colorectal, 7 on urology, 11 on gynecology, 2 on gastric surgery. Fluorescence guide has shown advantages on the length of hospitalization particularly in colorectal surgery, with a reduction of the rate of leakages and re-do anastomoses, in spite of a slight increase in operating time, and is confirmed to be a safe, efficacious, and sustainable vision technology. Clinical applications are still presenting a low evidence in the literature.

CONCLUSION

The present paper, under the patronage of Italian Society of Endoscopic Surgery, based on an HTA approach, sustains the use of fluorescence-guided vision in minimally invasive surgery, in the fields of general, gynecologic, urologic, and thoracic surgery, as an efficient and economically sustainable technology.

Intraoperative Indocyanine Green (ICG) Angiography for the Identification of the Parathyroid Glands: Current Evidence and Future Perspectives

BACKGROUND/AIM

Recently, indocyanine green (ICG) fluorescence imaging has been used for the identification of the parathyroid glands (PG) during thyroid and parathyroid surgery. However, an overall consensus on the optimal technique, the dosage, the timing of the ICG administration and finally its interpretation and clinical usefulness is still lacking evidence. The aim of this review is to investigate the use of ICG angiography during thyroidectomy and/or parathyroidectomy for identification as well as for the perfusion integrity of the parathyroid glands.

MATERIALS AND METHODS

The PubMed database was systematically searched for publications regarding intraoperative ICG imaging in patients that undergo thyroidectomy or parathyroidectomy.

RESULTS

Eighteen publications reporting on 612 patients, namely 71 parathyroidectomy and 541 thyroidectomy patients met the inclusion criteria. Eleven publications reported the use of ICG angiography for the identification of the parathyroid glands during thyroidectomy and seven during parathyroidectomy for primary and secondary hyperparathyroidism.

CONCLUSION

ICG fluorescence imaging is a simple, fast and reproducible method capable of intraoperatively visualizing and assessing the function of parathyroid glands, and can, therefore, assist surgeons in their decision-making. Despite all this, ICG fluorescence imaging technique for PG detection still lacks standardization and further studies are needed to establish its clinical utility.

Classification of hyperspectral endocrine tissue images using support vector machines

BACKGROUND

Thyroidectomy is one of the most commonly performed surgical procedures. The region of the neck has a very complex structural organization. It would be beneficial to introduce a tool that can assist the surgeon in tissue discrimination during the procedure. One such solution is the noninvasive and contactless technique, called hyperspectral imaging (HSI).

METHODS

To interpret the HSI data, we implemented a supervised classification method to automatically discriminate the parathyroid, the thyroid, and the recurrent laryngeal nerve from surrounding tissue(muscle, skin) and materials (instruments, gauze). A leave-one-patient-out cross-validation was performed.

RESULTS

The best performance was obtained using support vector machine (SVM) with a classification and visualization in less than 1.4 seconds. A mean patient accuracy of 68% ± 23% was obtained for all tissues and material types.

CONCLUSIONS

The proposed method showed promising results and have to be confirmed on a larger cohort of patient data.

Near-infrared fluorescence in robotic thyroidectomy

New imaging techniques using near-infrared (NIR) fluorescence in combination with remote access thyroidectomy have been studied in endocrine surgery to determine their utility, with the goal of reducing potential complications. Indocyanine green (ICG) imaging is a safe adjunct to remote access thyroid surgery. Nevertheless, experience with ICG is limited, and the caveats surrounding the use of ICG imaging in conventional thyroid surgery exist in remote access surgery as well. This report describes the various remote access techniques and considers the advantages and potential disadvantages of ICG in remote access thyroidectomy.

Endoscopic parathyroidectomy: a retrospective review of 27 cases

BACKGROUND

Primary hyperparathyroidism is a common endocrine disorder with adenomas being the most frequent cause. The condition is conventionally treated by a bilateral neck exploration through a cervical incision with removal of the affected glands. Intra-operative parathyroid hormone (IOPTH) monitoring and pre-operative Tc99m MIBI scans are facilitating focused approaches like minimally invasive video-assisted parathyroidectomy (MiVAP) and totally endoscopic parathyroidectomy (TOEP).

METHODS

Patients with primary hyperparathyroidism were tested for location of diseased gland and accordingly selected for endoscopic parathyroidectomy by either trans-vestibular or trans-axillary approach. Those having undergone prior neck surgery or irradiation and those with an enlarged thyroid were excluded. All patients underwent IOPTH measurement to confirm the completeness of diseased gland resection.

RESULTS

Eleven cases meeting selection criteria underwent endoscopic trans-vestibular parathyroidectomy and 16 cases underwent endoscopic trans-axillary parathyroidectomy. The mean operative time and blood loss were 104 min and 34 mL in trans-vestibular approach, respectively, while they were 47 min and 68 mL for the trans-axillary approach. All patients had post-operative resolution of hypercalcaemia. A single conversion to cervical approach was performed due to unsatisfactory IOPTH fall. A single patient suffered transient recurrent laryngeal nerve palsy which resolved with steroids.

CONCLUSION

Endoscopic parathyroidectomy is a safe and feasible surgical procedure when combined with pre-operative imaging and intra-operative parathyroid hormone monitoring. There is a steady rise in the number of patients with primary hyperparathyroidism, a majority of whom have solitary gland affliction. Focused exploration is the current standard, wherein endoscopic surgery can be an important tool to improve outcomes.

Impact of incidental parathyroidectomy and mediastinal-recurrent cellular and lymph-node dissection on parathyroid function after total thyroidectomy

OBJECTIVES

To determine the impact of incidental parathyroidectomy and mediastinal-recurrent cellular and lymph-node dissection on parathyroid function after total thyroidectomy.

MATERIAL AND METHODS

A single-center retrospective study was conducted for a 5-year period in a university hospital center, including 605 patients undergoing total thyroidectomy, 52 of whom had mediastinal-recurrent cellular and lymph-node dissection.

ENDPOINTS

The main endpoint was intraoperative number of parathyroid glands as predictor of parathyroid hormone (PTH) level and postoperative hypocalcemia. The secondary endpoint was the correlation between associated mediastinal-recurrent cellular and lymph-node dissection and incidental parathyroidectomy and its impact on PTH level and calcemia in the immediate postoperative period and at 1 month.

RESULTS

161 patients (26.61%) showed hypocalcemia in the immediate postoperative period and 12 (1.98%) at 1 month. Mediastinal-recurrent cellular and lymph-node dissection increased incidental parathyroidectomy risk 4.6-fold. Mediastinal-recurrent cellular and lymph-node dissection was associated with a statistically "suggestive" decrease in day-1 calcemia (P=0.03), and no significant decrease at 1 month (P=0.52). Incidental parathyroidectomy (6.7% of cases with parathyroidectomy versus 1.3% without) did not significantly increase the rate of early hypocalcemia (P=0.28), but was associated with a "suggestive" worsening at 1 month (P=0.02).

CONCLUSION

Hypocalcemia after total thyroidectomy is a complex, probably multifactorial issue. Systematic parathyroid gland identification is not recommended due to the increased risk of gland lesion, mainly by devascularization. Incidental parathyroidectomy may induce hypocalcemia at 1 month postoperatively (statistically "suggestive" association).

New Advances of ICG Angiography in Parathyroid Identification

Objective:

For surgeons, locating parathyroid in thyroidectomy and parathyroidectomy is critical since parathyroid plays an important role in calcium balance. The fluorescence of parathyroid has already been found by researchers and the angiography equipment detecting the fluorescence of parathyroid with indocyanine green has been widely applied. Using the indocyanine green angiography and looking at the actual fluorescence of in vivo and in vitro tissues, it was possible to identify thyroid, parathyroid, lymph nodes and fat tissues during the surgical procedure. This mini-review aims to present the application of indocyanine green angiography in parathyroid detection and discusses the safety of this method.

Methods:

The relevant data were searched by using the keywords “Indocyanine green,” “Parathyroid,” and “Identification” and “Protection” in “Pubmed,” “Web of Science” and “China Knowledge Resource Integrated databases”, and a manual search was done to acquire peer-reviewed articles and reports about indocyanine green.

Results:

Indocyanine green dye along with the intraoperative fluorescence imaging system is safe in detecting parathyroid and predicting postoperative hypoparathyroidism.

Conclusion:

The conclusion suggests that indocyanine green angiography is a safe, effective and easy way to detect parathyroid glands. The conclusion will be of interest to surgeons regarding thyroidectomy and parathyroidectomy.

Impact of fluorescence and autofluorescence on surgical strategy in benign and malignant neck endocrine diseases

Fluorescence and autofluorescence have been shown by several recent studies to be valuable adjuncts in identifying parathyroid glands during thyroidectomy and parathyroidectomy. The aim of this chapter is to review the impact of this new technology on surgical strategy concerning identification and preservation of parathyroid glands during thyroidectomy, identification of parathyroid glands in hyperparathyroidism, and the potential role in thyroid cancer surgery.

Intraoperative Near-infrared Imaging Can Identify Neoplasms and Aid in Real-time Margin Assessment During Pancreatic Resection

OBJECTIVE

To determine if intraoperative near-infrared (NIR) imaging carries benefit in resection of pancreatic neoplasms.

BACKGROUND

Resection of pancreatic malignancies is hindered by high rates of local and distant recurrence from positive margins and unrecognized metastases. Improved tumor visualization could improve outcomes. We hypothesized that intraoperative NIR imaging with a clinically approved optical contrast agent could serve as a useful adjunct in assessing margins and extent of disease during pancreatic resections.

METHODS

Twenty patients were enrolled in an open-label clinical trial from July 2016 to May 2018. Subjects received second window indocyanine green (ICG) (2.5-5 mg/kg) 24 hours prior to pancreatic resection. NIR imaging was performed during staging laparoscopy and after pancreas mobilization in situ and following resection ex vivo. Tumor fluorescence was quantified using tumor-to-background ratio (TBR). Fluorescence at the specimen margin was compared to pathology evaluation.

RESULTS

Procedures included 9 pancreaticoduodenectomies, 10 distal pancreatectomies, and 1 total pancreatectomy; 21 total specimens were obtained. Three out of 8 noninvasive tumors were fluorescent (mean TBR 2.59 ± 2.57). Twelve out of 13 invasive malignancies (n = 12 pancreatic adenocarcinoma, n = 1 cholangiocarcinoma) were fluorescent (mean TBR 4.42 ± 2.91). Fluorescence at the transection margin correlated with final pathologic assessment in 12 of 13 patients. Following neoadjuvant therapy, 4 of 5 tumors were fluorescent; these 4 tumors showed no treatment response on pathology assessment. One tumor had a significant treatment response and showed no fluorescence.

CONCLUSIONS

Second window ICG reliably accumulates in invasive pancreatic malignancies and provides real-time feedback during pancreatectomy. NIR imaging may help to assess the response to neoadjuvant therapy.

Transoral Endoscopic Thyroidectomy for Thyroid Cancer

The prevalence of low-risk differentiated thyroid cancer (DTC) is dramatically increasing because of superior diagnostic imaging technologies. Remote-access endoscopic thyroidectomy is becoming more popular for the lack of a noticeable neck scar. Transoral endoscopic thyroidectomy, vestibular approach (TOETVA) is the only technique that could be called a true scarless surgery; however, there is a scarcity of long-term studies about its safety and feasibility. Because thyroid cancer is a slow-growing lesion, with adequate follow-up and surveillance, TOETVA is a surgical procedure for the management of low-risk DTC without any difference of surgical and oncological outcome.

The use of Indocyanine green in endocrine surgery of the neck: A systematic review

BACKGROUND

The insufficient reliability of preoperative imaging technology and limited convenience of intraoperative visualizing techniques have been associated with difficulty in surgical navigation in neck endocrine surgery. Indocyanine green (ICG) fluorescence imaging has stood out as the real-time intraoperative guide amidst research for novel modalities, with an emerging use in endocrine surgery.

METHODS

We performed a systematic review of the PubMed, Scopus and Embase databases, to identify published studies on parathyroid and thyroid operations employing ICG. Well-described articles were selected according to 7 criteria and analyzed per operation type and organ structure.

RESULTS

Twenty-one articles matched our selection criteria. Dosage, equipment, and techniques are well-described in literature. ICG was found to significantly enhance the surgical experience and outcomes. Occasional discrepancy among studies was attributed to the lack of standard quantification of values and divergence of study designs.

CONCLUSION

The most successful applications of ICG are:Future research is needed for standard quantification of fluorescence intensity and objective comparisons.

The application of subcapsular saline injection during bilateral axillo-breast approach robotic thyroidectomy: a preliminary report

PURPOSE

Saving the parathyroid gland during robotic thyroidectomy is challenging. This study evaluated the application of a novel method, subcapsular saline injection (SCASI), to save the parathyroid gland during bilateral axillo-breast approach (BABA) robotic total thyroidectomy.

METHODS

Of the 81 included patients operated on from 2014 to 2016, 31 and 50 underwent BABA robotic total thyroidectomy with and without SCASI, respectively. Serum concentrations of parathyroid hormone (PTH), calcium, and ionized calcium were measured at 1 day and 9 months postoperatively. Transient hypoparathyroidism was defined as PTH < 10.0 pg/mL after 1 day and permanent hypoparathyroidism as PTH < 15.0 pg/mL at 9 months.

RESULTS

There were no significant clinicopathologic differences between the two groups. The rate of transient hypoparathyroidism was significantly lower in the SCASI group than in the non-SCASI group [16.1% (5/31) vs. 44% (22/50), p < 0.01]. However, the rates of permanent hypoparathyroidism [0% (0/31) vs. 4% (2/50), p = 0.699] did not differ significantly.

CONCLUSIONS

SCASI is a feasible and safe method of saving the parathyroid gland during BABA robotic total thyroidectomy.

Feasibility of indocyanine green fluorescence imaging for intraoperative identification of parathyroid glands during thyroid surgery

Background

This study assessed the feasibility of near‐infrared fluorescence imaging with indocyanine green (ICG) to identify the parathyroid glands (PGs) intraoperatively and to assess their perfusion after thyroid resection.

Methods

Patients undergoing elective thyroidectomy were enrolled in this prospective study. An intravenous bolus of 7.5 mg ICG was administered twice: the first bolus to identify the PGs before resection of the thyroid and the second to assess vascularization of the PGs after resection.

Results

A total of 30 operations in 26 patients were included. In 17 surgeries (56.7%), fluorescence imaging was of added value, especially to confirm the presence of a suspected PG. No intraoperative or postoperative complications occurred because of the use of ICG.

Conclusion

Near‐infrared fluorescence imaging with the use of ICG for intraoperative identification of the PGs and the assessment of its vascularization is feasible and safe and can provide more certainty about the location of the PGs.

Parathyroid gland management using optical technologies during thyroidectomy or parathyroidectomy: A systematic review

New optical technologies enhancing localization or assessing viability of parathyroid glands (PG) during endocrine surgery have been reported in clinical studies. These technologies could become complementary to the surgeon's eyes and may improve surgical outcomes in thyroidectomy and parathyroidectomy. Here, we conducted a systematic review focusing on PG identification and functional assessment using optical methods to enhance surgery. A systematic literature review was performed using MEDLINE and Embase database. Two authors selected studies and extracted data; qualitative analysis was performed to summarize the characteristics of reported optical tools for thyroidectomy or parathyroidectomy. Identification and vascularisation of PG during surgery were evaluated. Clinical and biochemical outcomes were appraised when reported. Studies relating to parathyroidectomy or thyroidectomy combined with autofluorescence, fluorescent methylene blue, 5-aminolevulinic acid, indocyanine green (ICG), optical coherence tomography, laser speckle contrast imaging, dynamic optical contrast imaging and Raman spectroscopy were identified with MEDLINE and Embase. We included a total of 47 relevant articles with a total of 1615 patients enrolled. Each optical technique is described and appreciated related to its surgical purpose. Autofluorescence and ICG imaging of PG are the most widely reported optical technologies for identification and assessment of vascularisation of PG. Results are mainly based on observational studies and argue for the feasibility of both techniques in endocrine surgery but prospective randomized studies have not been performed. In vivo applications are still limited for the other methods and further investigations correlating these techniques with post-operative parathormone measurements are still needed before considering these technologies in clinical practice.

Fluorescence imaging-guided robotic thyroidectomy and central lymph node dissection

BACKGROUND

The purpose of this study was to evaluate the feasibility of complete central compartment node dissection (CCND) using fluorescence imaging (FI) during robotic thyroidectomy.

METHODS

A total of 110 patients underwent robotic thyroidectomy and CCND from August 2015 to June 2016; 55 patients underwent robotic surgery using FI (FI group) and the other 55 patients without it (control group). The FI group was injected with indocyanine green into the thyroid to enhance the identification of lymph nodes (LNs).

RESULTS

Indocyanine green-stained LNs were easily detected using FI. The number of harvested LNs was 7.0 in the FI group and 4.8 in the control group (P = 0.004). There was lower rate of transient hypocalcemia in the FI group (18.5%) than control group (26.7%), but there was no significant difference (P = 0.417). There were no other significant differences between the two groups.

CONCLUSIONS

The use of FI during robotic thyroidectomy facilitated the identification of LNs and guided complete CCND.