Indocyanine green dye angiography as an adjunct to assess indeterminate burn wounds: A prospective, multicentered, triple-blinded study

Utility of indocyanine green fluorescent dye in emergency general surgery: a review of the contemporary literature

For decades, indocyanine green (ICG) has been available for medical and surgical use. The indications for ICG use in surgery have expanded where guided surgery directed by fluorescence and near-infrared fluorescent imaging offers numerous advantages. Recently, surgeons have reported using ICG operative navigation in the emergency setting, with fluorescent cholangiography being the most common procedure. The utility of ICG also involves real-time perfusion assessment, such as ischemic organs and limbs. The rising use of ICG in surgery can be explained by the ICG's rapid technological evolution, accuracy, ease of use, and great potential to guide precision surgical diagnosis and management. The review aims to summarize the current literature on the uses of ICG in emergency general surgery. It provides a comprehensive and practical summary of the use of ICG, including indication, route of administration, and dosages. To simplify the application of ICG, we subdivided its use into anatomical mapping and perfusion assessment. Anatomical mapping includes the biliary tree, ureters, and bowel. Perfusion assessment includes bowel, pancreas, skin and soft tissue, and gonads. This review provides a reference to emergency general surgeons to aid in implementing ICG in the emergency setting for more enhanced and safer patient care.

Lighting the Way for Necrosis Excision Through Indocyanine Green Fluorescence-Guided Surgery

BACKGROUND

No objective technique exists to distinguish necrotic from viable tissue, risking over-excision in burns and loss of wound healing potential. Second window indocyanine green (SWIG) is a novel fluorescence-imaging modality being studied to identify residual solid tumors during oncological surgery. SWIG has also been shown to have avidity for necrosis in animal models, but translation of these findings to humans is lacking. The objective of this study was to evaluate SWIG in the identification of burn wound necrosis and compare it with previously published indocyanine green angiography (ICGA) techniques.

STUDY DESIGN

This study used mouse, human skin xenograft and human patient burn models. Brightfield and SWIG near-infrared imaging were performed on macroscopic tissue samples, which were then cryopreserved, sectioned, and analyzed for microscopic fluorescence. SWIG fluorescence findings were correlated to visual assessment of the burn wound as well as histological markers of necrosis using hematoxylin and eosin and lactate dehydrogenase stains.

RESULTS

We found that SWIG identified burn necrosis in a manner dependent on the dose and timing of indocyanine green (ICG) administration and had an inverse fluorescence signal compared with ICGA. Furthermore, SWIG fluorescence identified the interface of viable and nonviable tissue.

CONCLUSION

Our study confirmed that ICGA is an inconsistent and nonstandardized modality to evaluate burn injuries. In contrast, SWIG imaging is a potential imaging modality to objectively prognosticate burn wound healing potential and guide intraoperative burn excision. Further studies are needed to define ratios of fluorescence intensity values to guide surgical decision-making in burn excision and to better define how ICG is retained in necrotic tissue to enhance utility of SWIG in other disease processes.

Bedside Fluorescence Microangiography for Frostbite Diagnosis in the Emergency Department

Frostbite leads to progressive ischemia eventually causing tissue necrosis if not quickly reversed. Patients with frostbite tend to present to the emergency department (ED) for assessment and treatment. Acute management includes rewarming, pain management, and (when indicated) thrombolytic therapy. Thrombolytic therapy in severe frostbite injury may decrease rates of amputation and improve patient outcomes. Fluorescence microangiography (FMA) has been used to distinguish between perfused and non-perfused tissue. The purpose of this study was to evaluate the potential role of FMA in the acute care of patients with frostbite, specifically its role as a tool to identify perfusion deficit following severe frostbite injury, and to explore its role in time to tissue plasminogen activator (tPA). Methods: This retrospective analysis included all patients from December 2020–March 2021 who received FMA in a single ED as part of their initial frostbite evaluation. In total, 42 patients presented to the ED with concern for frostbite and were evaluated using FMA. Results: Mean time from arrival in the ED to FMA was 46.3 minutes. Of the 42 patients, 14 had clinically significant perfusion deficits noted on FMA and received tPA. Mean time to tPA (measured from ED arrival to administration of tPA) for these patients was 117.4 minutes. This is significantly faster than average historical times at our institution of 240-300 minutes. Conclusion: Bedside FMA provides objective information regarding perfusion deficits and allows for faster decision-making and improved times to tPA. Fluorescence microangiography shows promise for quick and efficient evaluation of perfusion deficits in frostbite-injured patients. This could lead to faster tPA administration and potentially greater rates of tissue salvage after severe frostbite injury.

Intraoperative angiography imaging correlates with wound complications following soft tissue sarcoma resection

For soft tissue sarcoma patients receiving preoperative radiation therapy, wound complications are common and potentially devastating. The purpose of this study was to assess the feasibility of intraoperative indocyanine green fluorescent angiography (ICGA) as a predictor of wound complications in these patients. A consecutive series of patients with soft tissue sarcoma of the extremities or pelvis who received neoadjuvant radiation and a subsequent radical resection received intraoperative ICGA with the SPY PHI device (Stryker Inc.) at the time of closure. Retrospective analysis of fluorescence signal along multiple points of the wound length was performed and quantified. The primary endpoint was wound complication, defined as delayed wound healing or wound dehiscence, within 3 months of surgery. Fourteen patients with preoperative irradiated soft tissue sarcoma were consecutively imaged. There were six patients with wound complications classified as "aseptic" in five cases. Using the ICGA, blinded surgeons correctly predicted wound complications in 75% of cases. During the inflow phase, a mean ratio of normal of 0.62 maximized the area under the curve (AUC = 0.90) for predicting wound complications with a sensitivity of 100% and specificity of 77.4%. During the peak phase, a mean ratio of normal of 0.55 maximized the AUC (0.95) for predicting wound complications with a sensitivity of 88.9% and a specificity of 100%. Intraoperative use of ICGA may help to predict wound complications in patients undergoing resection of preoperatively irradiated soft tissue sarcomas of the extremities and pelvis.

The Role of ICG Angiography in Decision Making About Skin-Sparing in Pediatric Acute Trauma

BACKGROUND

Indocyanine green (ICG) angiography has proven useful in assessing skin flap perfusion in plastic and reconstructive surgeries. This research aimed to explore its role in decision making about skin-sparing in children's acute trauma.

METHODS

A total of 19 patients suffering with acute trauma from January 2019 to September 2021 were retrospectively assessed. Both ICG angiography and clinical judgment were performed to evaluate skin tissue viability. The intraoperative decisions for each case depended on the specific condition of the traumatic wound, including tissue perfusion, skin defect area, and location of the wound. Postoperative vascular imaging software was used to quantify the tissue perfusion, and the duration of postoperative follow-up was from 6 to 18 months.

RESULTS

Among them, 18 (94.7%) patients experienced treatments according to ICG angiography and did not develop postoperative necrosis. One case with right forearm trauma suffered from partial necrosis. Hypertrophic scar and local infection were the independent complications, which were managed by symptomatic treatment.

CONCLUSION

ICG angiography may reduce the risk of postoperative necrosis and renders a promising adjunctive technique for surgeons to make reasonable decisions in skin sparing in acute pediatric trauma.

Fluorescence angiography-assisted debridement of critically perfused glabrous skin in degloving foot injuries: Two case reports

RATIONALE

Degloving foot injuries are challenging to treat and associated with life-long sequelae for patients. An appropriate debridement of ischemic soft tissues with maximal preservation of glabrous skin is key during the reconstruction of these injuries. Indocyanine green (ICG) fluorescence angiography is an established technique for the intraoperative evaluation of tissue perfusion.

PATIENT CONCERNS

Two patients sustained complex foot injuries in traffic accidents, including multiple fracture dislocations and extensive degloving of the plantar skin.

DIAGNOSIS

Clinical inspection revealed significant degloving of the glabrous skin in both patients.

INTERVENTIONS

After fracture fixation, ICG fluorescence angiography-assisted debridement with immediate latissimus dorsi free flap reconstruction was performed.

OUTCOMES

In both cases, this technique allowed a precise debridement with maximal preservation of the glabrous skin. The healing of the remaining glabrous skin was uneventful and the 6-month follow-up was characterized by stable soft tissues and satisfying ambulation.

LESSONS

ICG fluorescence angiography is a safe, user-friendly, and quick procedure with minimal risks, expanding the armamentarium of the reconstructive surgeon. It is highly useful for the debridement of extensive plantar degloving injuries and may also help to minimize the number of procedures and the risk of infection.

Indocyanine Green Angiography Precise Marking for Indeterminate Burn Excision: A Prospective, Multi-centered, Double-blinded Study

BACKGROUND

During burn excision, the clinical judgment whether to excise or not excise the area with indeterminate burn depth is difficult. Indocyanine green angiography (ICGA) has been reported to provide high accuracy in diagnosing indeterminate burns. This study aims to evaluate the complete wound closures in both short-term and long-term outcomes after using ICGA precise marking to guide indeterminate burn excision.

METHODS

This was a prospective, multi-centered, double-blinded, experimental study. The participants were admitted to the hospital with indeterminate burn wounds. ICGA precise marking was performed. The deep second-degree burn was painted, excised, and subsequently covered with skin grafts and measured on day 5. The superficial burns were measured on day 21. All wounds were followed-up at two months.

RESULTS

Thirty indeterminate burn sites were included in this study. Using ICGA precise marking, the overall rate of short-term complete wound closure, which combined superficial and deep burns, was found to be as high as 96.7% (29/30). The long-term complete wound closures at two months confirmed the short-term result and yielded 100.0% of complete wound closure. The complete wound closures between the short-term and long-term measurements were not significantly different (P > 0.999).

CONCLUSIONS

Using ICGA precise marking to guide indeterminate burn excision resulted in an excellent rate of complete wound closure and an insignificant difference between short-term and long-term wound outcomes. ICGA is a competent method to aid decision-making in burn surgery of the indeterminate area.

An Inconvenient Truth of Clinical Assessment and Indocyanine Green Angiography Precise Marking for Indeterminate Burn Excision

Background:

The clinical assessment of indeterminate burn wounds has relatively poor accuracy. Indocyanine green angiography (ICGA) has high accuracy and can be used to mark wounds precisely so as to guide burn excision. This study aimed to assess the differences between ICGA and clinical assessment marking and compare the marking result with the long-term wound outcome.

Methods:

This was a prospective, multicentered, triple-blinded, experimental study. Indeterminate burn wounds were clinically assessed, and the area to be excised was firstly marked by the attending surgeon. ICGA marking was then performed by a second surgeon. Measurement of the marked area was conducted by a third surgeon. Three surgeons were each blinded to the others' processes. The wounds were followed up to assess complete wound closures on day 21.

Results:

There were 20 burn sites included in the study. There was a significant difference in the marked areas between clinical assessment and ICGA (mean, 57.3 ± 44.1%; P = 0.001). The maximum difference found was as high as 160.9%. The correction rate of ICGA marking to complete wound closure on day 21 was 95.0%. Over 90% of the decreased areas of excision—which were assessed by ICGA to be superficial burns but evaluated by clinical assessment to be deep burns—were completely healed on day 21.

Conclusions:

ICGA contributes to a significant difference versus clinical assessment in the marking for excision of indeterminate burns and strongly associates with long-term wound outcomes. The burn wounds can be assessed precisely to reduce unnecessary excision and prevent inadequate excision.

A Critical Update of the Assessment and Acute Management of Patients with Severe Burns

Significance: Burns are debilitating, life threatening, and difficult to assess and manage. Recent advances in assessment and management have occurred since a comprehensive review of the care of patients with severe burns was last published, which may influence research and clinical practice. Recent Advances: Recent advances have occurred in the understanding of burn pathophysiology, which has led to the identification of potential biomarkers of burn severity, such as protein C. There is new evidence about the potential superiority of natural colloids over crystalloids during fluid resuscitation, and new evidence about components of initial and perioperative management, including an improved understanding of pain following burns. Critical Issues: The limitations of the clinical examination highlight the need for imaging and biomarkers to assist in estimations of burn severity. Fluid resuscitation reduces mortality, although there is conjecture over the ideal method. The subsequent perioperative period is associated with significant morbidity and the evidence for preventing and treating pain, infection, and fluid overload while maximizing wound healing potential is described. Future Directions: Promising developments are ongoing in imaging technology, histopathology, biomarkers, and wound healing adjuncts such as hyperbaric oxygen therapy, topical negative pressure therapy, stem cell treatments, and skin substitutes. The greatest benefit from further research on management of patients with burns would most likely be derived from the elucidation of optimal fluid resuscitation protocols, pain management protocols, and surgical techniques from randomized controlled trials.