The use of acellular products in venous leg ulcers: a narrative review.

BACKGROUND: Venous leg ulcers (VLUs) are the most common type of chronic wound in the lower extremity and are often associated with redness, swelling, and pain at the site of the wound. The primary focus of VLU treatment is the promotion of wound healing through compression therapy, wound debridement, and elevation of the affected limb. Acellular matrices have gained traction as a potential adjunct to wound healing in diabetic foot ulcers. However, the clinical effect of acellular products in the setting of VLUs has not been well reported. OBJECTIVE: To review the published evidence on the use of acellular products in the management of VLUs. METHODS: PubMed, Embase, Cochrane, and Google Scholar databases were initially searched on March 2, 2023, for literature on VLU and acellular dermal matrix. Later, the search was broadened to include any and all acellular matrices, and a secondary search of the same databases was conducted on February 20, 2024. Articles obtained through collateral methods were also included. RESULTS: A total of 27 articles were identified for review. All studies were human studies. Four articles had level I evidence and 7 articles had level II evidence, while the remaining articles had level III or IV evidence. Studies included both large and small wound sizes ranging from 0.5 cm² to 100 cm2. Product application occurred once to twice weekly for 4 weeks to up to 36 months. Overall, regardless of ulcer size, the majority of studies reported favorable wound healing outcomes with the use of a variety of acellular skin coverage products with few complications. Some studies also reported pain reduction with the use of acellular skin substitutes in a small cohort of patients. CONCLUSION: Acellular products appear to have the potential to support healing in VLUs. However, more large-scale randomized controlled trials that provide level I evidence are needed.

Fully implanted battery-free high power platform for chronic spinal and muscular functional electrical stimulation.

Electrical stimulation of the neuromuscular system holds promise for both scientific and therapeutic biomedical applications. Supplying and maintaining the power necessary to drive stimulation chronically is a fundamental challenge in these applications, especially when high voltages or currents are required. Wireless systems, in which energy is supplied through near field power transfer, could eliminate complications caused by battery packs or external connections, but currently do not provide the harvested power and voltages required for applications such as muscle stimulation. Here, we introduce a passive resonator optimized power transfer design that overcomes these limitations, enabling voltage compliances of ± 20 V and power over 300 mW at device volumes of 0.2 cm2, thereby improving power transfer 500% over previous systems. We show that this improved performance enables multichannel, biphasic, current-controlled operation at clinically relevant voltage and current ranges with digital control and telemetry in freely behaving animals. Preliminary chronic results indicate that implanted devices remain operational over 6 weeks in both intact and spinal cord injured rats and are capable of producing fine control of spinal and muscle stimulation.