Feasibility of parathyroid gland autofluorescence imaging after indocyanine green fluorescence angiography

Background

In thyroid surgery, autofluorescence allows the parathyroid glands (PTGs) to be located very early to protect them. Moreover, indocyanine green (ICG) fluorescence angiography (ICG-FA) allows for assessing the viability of the PTGs and identifying blood vessels to preserve them. The main limitation of using ICG-FA is that once ICG has been injected, it is no longer possible to observe PTG autofluorescence using existing devices. This study aimed to describe an approach that allows for visualization of the PTGs by autofluorescence, even after ICG injection.

Methods

We redesigned the FLUOBEAM® LX system to excite fluorescence at 685 nm and detect fluorescence between 700 and 900 nm. This device had short-pass filters at 775 nm that helped to split the contributions of the PTG autofluorescence and ICG fluorescence. Tests were performed on extemporaneous PTG preparations placed next to ICG droplets to assess for rejection of the ICG signal.

Results

A low-pass filter at 775 nm detected 60% of the autofluorescence signals and 10% of the ICG signals.

Conclusion

These findings support the possibility of visualizing PTG autofluorescence despite multiple ICG injections and measuring the balance between ICG and autofluorescence signals.

A quantitative assessment of perfusion of the gastric conduit after oesophagectomy using near-infrared fluorescence with indocyanine green

INTRODUCTION

Anastomotic leakage is a severe complication after oesophageal resection with gastric conduit reconstruction. Poor perfusion of the gastric conduit plays an important role in the development of anastomotic leakage. Quantitative near-infrared (NIR) fluorescence angiography with indocyanine green (ICG-FA) is an objective technique that can be used for perfusion assessment. This study aims to assess perfusion patterns of the gastric conduit with quantitative ICG-FA.

METHODS

In this exploratory study, 20 patients undergoing oesophagectomy with gastric conduit reconstruction were included. A standardized NIR ICG-FA video of the gastric conduit was recorded. Postoperatively, the videos were quantified. Primary outcomes were the time-intensity curves and nine perfusion parameters from contiguous regions of interest on the gastric conduit. A secondary outcome was the inter-observer agreement of subjective interpretation of the ICG-FA videos between six surgeons. The inter-observer agreement was tested with an intraclass correlation coefficient (ICC).

RESULTS

In a total of 427 curves, three distinct perfusion patterns were recognized: pattern 1 (steep inflow, steep outflow); pattern 2 (steep inflow, minor outflow); and pattern 3 (slow inflow, no outflow). All perfusion parameters were significantly different between the perfusion patterns. The inter-observer agreement was poor - moderate (ICC:0.345,95%CI:0.164-0.584).

DISCUSSION

This was the first study to describe perfusion patterns of the complete gastric conduit after oesophagectomy. Three distinct perfusion patterns were observed. The poor inter-observer agreement of the subjective assessment underlines the need for quantification of ICG-FA of the gastric conduit. Further studies should evaluate the predictive value of perfusion patterns and parameters on anastomotic leakage.

Indocyanine Green (ICG) fluorescence angiography of gastric conduit after transhiatal thoracic esophagectomy with proximal gastrectomy for esophagogastric junction adenocarcinoma: A case report and initial experience at a tertiary government hospital in the Philippines

INTRODUCTION AND IMPORTANCE

We documented the initial experience in our institution where we used indocyanine green (ICG) fluorescence angiography as adjunct in the evaluation of the vascular supply of a reconstructed gastric conduit for esophageal replacement for esophagogastric junction (EGJ) cancer surgery.

CASE PRESENTATION

A 62-year-old patient consulted with a two-month history of melena and weight loss and unremarkable chest and abdominal physical examinations.

CLINICAL FINDINGS AND INVESTIGATIONS

Upper endoscopy and contrast-enhanced computed tomography scans of the chest and abdomen demonstrated an EGJ tumor with no nodal and distant metastases, which revealed adenocarcinoma on biopsy.

INTERVENTION AND OUTCOME

The patient underwent combined thoracoscopic-assisted and transhiatal thoracic esophagectomy with proximal gastrectomy. Esophageal reconstruction was done via a retrosternal gastric pull-up. The perfusion and viability of the gastric conduit were confirmed as per usual methods of inspection and palpation. ICG fluorescence angiography further demonstrated and confirmed the vascular perfusion of the gastric conduit and the optimal site of anastomosis. The patient had an unremarkable postoperative course with no reported anastomotic leakage and stricture formation at 12 months follow-up.

RELEVANCE AND IMPACT

ICG fluorescence angiography represents a feasible and promising tool in assessing viability of esophageal replacement and choosing the optimal site for anastomosis with the proximal esophagus. It can aid in choosing the most appropriate site of anastomosis to prevent ischemia-related complications such as leakage or stricture. This particular case can serve as an initial learning experience to guide surgeons in our institution in the use of ICG fluorescence angiography for esophageal replacements after esophagectomy.

Intraoperative real-time fluorescence angiography with indocyanine green for evaluation of intestinal viability during surgery for an incarcerated obturator hernia: a case report

Background

Bowel incarceration represents a dreaded complication amongst patients with hernias. The intraoperative evaluation of the bowel perfusion following hernia reduction with regard to the need for resection of ischaemic bowel can be challenging. In this case report we discuss intraoperative fluorescence angiography with indocyanine green (ICG) as an objective means of accessing bowel perfusion following hernia reduction.

Case presentation

The case of a 92-year-old, caucasian, female patient presenting with symptoms of small bowel obstruction secondary to an incarcerated left sided obturator hernia is presented. An incarcerated segment of the small bowel was reduced during emergency laparoscopy. Intraoperative ICG fluorescence angiography revealed ischaemic changes in the normal appearing bowel, so that the involved segment was resected. The postoperative course was uneventful and the patient was discharged home safely on postoperative day seven.

Conclusion

Intraoperative ICG fluorescence angiography provides an objective method of judging bowel perfusion and therefore represents a useful tool for assessing intestinal perfusion in patients with incarcerated hernia.