Diabetic foot ulcers (DFUs) are one of the most common and debilitating complications of diabetes, with estimates suggesting that approximately 34% of people with diabetes will develop a foot ulcer during their lifetime. That means that between 40 million to 60 million people worldwide are affected by DFUs each year. DFUs often lead to chronic wounds, infections, and if left untreated, can result in amputation.
Managing DFUs requires a multidisciplinary approach that includes wound care, infection control, and, in some cases, surgical intervention. One promising advancement in the management of DFUs is the use of indocyanine green (ICG), a fluorescent dye that has found numerous applications in the medical field, including in the assessment and treatment of diabetic foot ulcers.
What is Indocyanine Green (ICG)?
Indocyanine green is a water-soluble dye that fluoresces under near-infrared light. It was initially introduced in the 1950s for use in ophthalmology, assessing cardiac output and liver function. Over time, its potential for imaging vascular structures was recognised, making it an invaluable tool in various clinical settings, including surgery, dermatology and wound care. ICG is injected into the bloodstream and circulates, binding to plasma proteins. This binding allows for real-time imaging of vascular structures through near-infrared light, providing valuable insights into tissue perfusion and viability.
In the context of DFU management, ICG plays a pivotal role in visualising blood flow to the affected tissue, detecting ischemia, and guiding surgical interventions. Its ability to provide continuous, real- time feedback also allows healthcare providers to monitor and treat diabetic foot ulcers beyond its use in surgical procedures.
Surgical Applications of ICG in Diabetic Foot Ulcer Management
One of the most significant challenges in treating DFUs is ensuring adequate blood supply to the affected area. Poor circulation, a hallmark of diabetes, often complicates wound healing and increases the risk of infections. In these cases, surgical intervention may be necessary to restore blood flow, remove necrotic tissue or address structural deformities. Indocyanine green can be instrumental in guiding these surgical procedures.
- Assessment of Vascularity
- ICG allows for real-time, intraoperative assessment of tissue perfusion. Surgeons can use ICG to identify areas of compromised blood flow in the foot, enabling them to make more informed decisions about which areas require debridement, revascularisation or further intervention. By injecting ICG and visualising its circulation through the tissue under near-infrared light, the surgeon can evaluate the viability of tissue before making irreversible decisions.
- For example, if a diabetic foot ulcer is surrounded by areas of ischemia (poor blood flow), ICG imaging can highlight these regions and allow the surgeon to target revascularisation procedures to the affected vessels. In some cases, procedures such as bypass surgery, angioplasty, or the use of biologic agents to stimulate angiogenesis (the formation of new blood vessels) can be performed with the precise knowledge of where blood flow is lacking. This reduces the risk of leaving non-viable tissue that may lead to further complications or the need for more extensive amputations.
- Guiding Debridement and Excision
- ICG also helps in guiding debridement or excision of necrotic tissue in the wound bed. Necrotic tissue is a common problem in diabetic foot ulcers and serves as a breeding ground for bacteria. Removing this tissue is essential for creating a healthy wound bed conducive to healing. ICG can assist surgeons by highlighting areas of necrosis or poor perfusion, ensuring that only non-viable tissue is removed while sparing healthy tissue. This targeted approach minimises trauma to surrounding healthy tissue and accelerates wound healing.
- Monitoring Revascularisation Procedures
- For diabetic patients with critical limb ischemia, revascularisation procedures such as bypass grafting, angioplasty, or stenting are frequently necessary to restore blood flow to the affected limb. ICG imaging is used to evaluate the success of these procedures by allowing surgeons to assess whether the blood flow is adequately restored to the foot and whether there is sufficient perfusion to support wound healing. Surgeons can make adjustments to the procedure in real-time, ensuring that the patient receives the optimal treatment.
Continuous Assessment and Monitoring of Diabetic Foot Ulcers with ICG
While surgical interventions are crucial for the management of DFUs, continuous monitoring of the wound and surrounding tissue is equally important to assess healing progress and detect complications early. Traditionally, wound assessment relies on clinical examination, sometimes supplemented by imaging techniques such as Doppler ultrasound or angiography. However, these methods can be invasive, time-consuming and may not provide real-time data. ICG offers an innovative, non-invasive, and real-time solution for continuous monitoring.
- Assessing Tissue Perfusion and Viability
- One of the primary challenges in DFU management is assessing the perfusion and viability of tissue at the wound site. Non-healing ulcers may be a result of insufficient blood supply to the affected area, making healing impossible without intervention. By using ICG imaging, healthcare providers can regularly assess the blood flow to the wound site, ensuring that any areas of poor perfusion are identified early. This allows for timely interventions, such as adjusting wound care protocols, modifying treatment regimens or considering revascularisation if necessary.
- Monitoring Infection and Wound Healing
- ICG can also aid in detecting infection and monitoring the progression of wound healing. Infected tissue typically shows altered blood flow patterns due to the inflammatory response, which can be detected using ICG.
- Additionally, the continuous assessment of blood flow can help monitor the effectiveness of ongoing treatments and determine if the wound is progressing towards closure or if additional interventions are needed.
- This dynamic monitoring approach is a significant advantage over traditional wound assessment methods that may rely on periodic evaluations.
- Evaluating the Effectiveness of Interventions
- The dynamic nature of DFU treatment means that wound care strategies need to be regularly updated based on patient response. ICG allows for the real-time evaluation of how the tissue is responding to specific treatments, such as debridement, the application of growth factors or the use of advanced dressings.
- If blood flow is restored to the wound, for example, ICG imaging can confirm the effectiveness of revascularisation efforts. Conversely, if poor perfusion persists, the clinician can consider further interventions.
Conclusion
Indocyanine green represents a significant innovation in the management of diabetic foot ulcers, offering both surgical and continuous monitoring advantages. In surgical applications, ICG provides real-time insights into tissue perfusion, guiding revascularisation, debridement and excision decisions to improve outcomes and reduce the need for amputation. Beyond surgery, ICG enables continuous, non-invasive monitoring of wound healing, infection and tissue viability, ensuring that clinicians can make informed, timely decisions about patient care.
The integration of ICG into diabetic foot ulcer management has the potential to transform clinical practice, offering a more precise, patient-centered approach to care. While further research and clinical validation are needed to optimise its use in routine clinical settings, the promise of ICG as a tool for both surgical intervention and continuous assessment marks an exciting development in the ongoing effort to improve outcomes for patients with diabetic foot ulcers.
