The purpose of the study is to evaluate the use of the SPY Elite System to assess real-time tissue perfusion of lower extremity amputation sites and to develop parameters to predict healing of amputations at the time of surgery.

This is a pilot study to see if the Spy Elite System is capable of recording accurate measurements on amputation sites to allow some correlation to healing. If this study shows promise for the device, the investigators would plan a larger study in which the data would be assessed in the operating room at time of acquisition and revision performed if needed based on the findings.

The pilot study is a prospective cohort study of consented subjects who require below knee or above knee amputation. The study will start with 18 subjects to assess proof of concept. If a correlation is identified, then a new proposal will be submitted with a larger cohort.

Our hypothesis is that the Spy Elite System can help identify areas of poor tissue perfusion at the time of lower extremity amputation, and predict future potential wound healing complications.

Primary outcome variables include wound healing at 30 days, and intra-operative imaging of amputation sites using the Spy Elite System. Secondary outcome variables include level of amputation, 30-day wound healing complications, readmission rate, need for revision, and subject demographics and co-morbidities.

Subjects who agree to participation will undergo the amputations in the operating suite as per routine. The Spy Elite System will be implemented after final wound closure and prior to dressing placement. A single injection of 10 mg of Indocyanine Green will be administered, followed by 10 ml bolus of normal saline as per manufacturer IFU and recommendations (Attachments B, C, D). Recording from the Spy Elite Device will be saved for analysis. Also, a digital photograph of the surgical wound will be saved for comparison. No changes in operative management based on Spy Elite System will take place in this study.

At subjects routine 30-day follow up appointment, wounds will be assessed for complications, a digital photograph of the incision will be saved, and secondary endpoints will be obtained.

Possible correlations between perfusion values from the Spy Elite System recording and wound healing will be analyzed by the Investigators. The values will not be known until after the photos are taken and the investigators compare ischemic areas to normal areas based on the collected photographs.

Inclusion Criteria:

• All patients >= 18 years of age requiring Below Knee Amputation (BKA) or Above Knee Amputation (AKA) cared for by the vascular surgery service will be assessed for eligibility.

Exclusion Criteria:

• Subjects with a history of allergies to iodides or iodinated contrast agents, pregnant or nursing women, subjects who are unable to provide consent, and prisoners will be excluded.

Currently there are no proven, reliable, objective tests to predict wound healing for amputations. Successful wound healing relies heavily on perfusion of the tissue flaps during amputation, which may already be compromised in peripheral vascular patients. Amputation failure results in repeat hospitalizations, surgeries and prolonged immobility for patients. The financial burden for patients and hospitals are significant, as is the psychological and emotional burden for patients facing repeat amputation. Failure rates for BKA and AKA amputations are 10% and 7% respectively. In elderly patients, readmission rates are as high as 27% with a mortality rate of 9% at 30 days.1 With improved ability to identify amputation sites at risk for wound complication and failure, we hope to decrease the need for readmission and repeat surgery.