Noncontact Low-Frequency Ultrasound for Debridement of Necrotic Wounds to Avoid Further Surgical Intervention: A Case Series

Purpose: Presence of necrotic tissue necessitates debridement to prevent disruption of healing and/or prepare wounds for flap/graft procedures. If removal of necrotic tissue allows for substantial wound healing, planned surgical interventions may be avoided entirely, resulting in lowered healthcare costs and patient morbidity.  Noncontact low-frequency ultrasound (NLFU)* is indicated for cleansing and maintenance debridement of slough, fibrin, tissue exudates, and bacteria.¹ In clinical studies, NLFU has been shown to accelerate healing in chronic lower-extremity wounds.^2-4
Case Series: NLFU was added to appropriate moist wound healing (e.g. saline gauze, silver gel, collagenase, petrolatum gauze) and short-term NPWT in 3 patients to assist with debriding necrotic tissue, cleansing wound beds, and preparing wounds for flaps/grafts.  Patient 1 underwent flap and graft procedures prior to admission on a crush-injury foot wound (170 cm²) that was necrotic (45% black eschar, 50% yellow slough) upon admission.  NLFU resulted in full granulation and 40% surface area reduction in 3 weeks, likely eliminating need for another graft/flap.  Patient 2 was at risk for bilateral lower-leg amputation due to bilateral circumferential calciphylaxis wounds (600 cm² and 468 cm²) that were necrotic (10-20% black eschar, 40-50% yellow slough) and painful. After 10 weeks of NLFU, wounds were clear of necrosis and were granulating, allowing for skin grafts to close wounds rather than bilateral amputation.  Patient 3 was admitted with a very large (1445 cm³) sacral/buttocks pressure ulcer with osteomyelitis and necrosis (40% black eschar, 40% yellow slough).  Eleven weeks of NLFU has resulted in substantial decrease in necrosis (15% yellow slough, 85% granulation) as well as 74% wound volume reduction. Skin graft surgery has been cancelled.
Implications: In 3 patients at risk for either lower-leg amputation or additional surgeries to close their wounds, NLFU reduced or eliminated need for surgical debridement and eliminated need for future surgical interventions.