Pilot study to assess the use of a fluorescence imaging system for assessment of amputation healing

The purpose of this study was to use a fluorescence imaging system (FIS) (SPYElite, NOVADAQ, US) during lower extremity amputations and develop parameters to predict amputation healing, for which there are no proven, objective tests. We hypothesised that the FIS may identify areas of poor perfusion at the time of amputation and predict potential healing complications. There are no studies involving the FIS used in this study in lower extremity amputation.

This prospective cohort study involved patients requiring either below- or above-knee-amputation at one, mid-western medical centre. The FIS was used as per manufacturer's instructions after wound closure and before dressing. Procedure and operative management was unchanged. Through the FIS, perfusion values were plotted along the amputation site to visualise and quantify intraoperative perfusion and to compare with 30-day postoperative amputation healing.

Surgeons determined that all of the 18 participants had adequate perfusion at surgical wound closure. At 30 days, two subjects had wound dehiscence or infection; these correlated with low perfusion values on the FIS imaging. A further six subjects had marginal or low perfusion values, but did not develop wound failure.

It is feasible to use the FIS during amputation, however it did not perfectly predict healing course based on vascular perfusion. There were interesting patterns of poor perfusion that correlated with areas of dehiscence or infection but other patients had reduced perfusion that healed well. Due to the small sample size, no discernible perfusion value differences existed between patients who healed and patients with healing complications. A future, larger study may show that the FIS can be predictive of patient healing and aid decisions for intraoperative revision.