Clinical Evaluation of the SNaP Wound Care System in Promoting Healing in Chronic Wounds

Inclusion Criteria: * Patient has diabetic foot ulceration, venous ulcer, or mixed aetiology ulcer with a surface area \<100 cm2 and \<10 cm in widest diameter on lower extremity, but larger than 1 cm2 (venous and mixed aetiology ulcers will be defined by clinical exam of treating physician. Diabetic foot ulcers will be defined by clinical exam of the treating physician and as lower extremity ulcers in patients with a diagnosis of diabetes, but without venous stasis disease). * Wound present for \>30 days. * Patient has wound in location amenable to creation of airtight seal around wound using TNP dressings. * Patient is able to comply with study protocol requirements. * Patient is able to understand and provide written consent. Exclusion Criteria: * Patient has evidence of wound infection in the opinion of the physician. * Patient has a thick eschar that persists after wound debridement. * Patient has an HbA1C \>12%. * Patient has ulcers due to inflammatory conditions such as pyoderma gangrenosum, rheumatoid arthritis, vasculitis, cryoglobulinaemia, necrobiosis lipoidica, panniculitis, lupus erythematosus, scleroderma, or calcinosis. * Patient has untreated osteomyelitis. * Patient has any other condition that, in the opinion of the investigator, makes the patient inappropriate to take part in this study. * Patient is allergic to the wound care device or occlusive dressing. * Patient has exposed blood vessels. * Patient is pregnant or pregnancy is suspected. * Patient is actively participating in other clinical trials that may interfere with their participation in this study.