Co-localization of High Bacterial Load with Regions of Pain in Venous Leg Ulcers: Fluorescence Imaging Informs Interventions and Validates Patient Self-Reported Pain

Introduction: Bacterial infections cause inflammation, tissue damage, and often significant pain for patients with chronic venous leg ulceration. No objective bedside methods exist for validating patient pain, making accurate assessment and management a challenge for wound care clinicians. While routinely using bacterial fluorescence imaging, we observed a recurrent co-localization of patient pain with regions of high bacterial loads. This prospective trial will aim to determine whether local, targeted treatment interventions could reduce pain associated with bacterial loads.Methods:A prospective clinical trial of 46 consecutive VLU patients who self-reported at the trial visit a wound-related pain score of >4 (Numerical Pain Score Assessment, 1-101). Patients with peripheral neuropathy were excluded, as well as those unable to report pain scores. Patients noted the location(s) of their pain on a printed photo of their wound. Then, we identified and recorded areas of high bacterial loads using a handheld bacterial fluorescence-imaging device*, along with any fluorescence-imaging informed treatment plan changes. Post-procedurally, either at the end of the trial visit or over the phone the next day, patients again rated their wound-related pain. Using these data, we semi-quantitatively assessed the colocalization of patient-reported pain and high bacterial loads and determined changes in pain score following localized treatments to remove bacterial loads.Results:100% of patients who reported moderate-severe VLU-associated had high bacterial loads in and/or around their wounds. In 87% of cases (40/46) there was some overlap between regions of patient reported pain and bacterial burden. Fluorescence-imaging guided wound bed preparation in 74% (34/46) of wounds, most commonly impacting the region and extent of wound cleansing or debridement. Average pain scores were significantly reduced following localized bacterial removal (8.17 [95% CI=7.65,8.70] to 6.87 [95% CI=6.11,7.63], p