Ultrasound for Open Wound Healing

 

The Problem

The use of therapeutic ultrasound for the treatment of open wounds

 

Justification

A randomized, controlled, double-blind study performed by Ennis et al investigated the effect of non-contact kHz ultrasound therapy to heal recalcitrant diabetic foot ulcers based on total closure and quantitative bacterial cultures as determined by culture biopsies.  The study included 97 subjects with type 1 or type 2 diabetes and with a chronic foot ulcer lasting longer than 30 days that was staged as a grade 1 or 2 ulcer. The study found that patients treated with US healed significantly quicker than the control group.  Wound recidivism at 3 months and wound culture biopsies were also improved in subjects receiving US, though not significantly. Adverse effects of cellulitis, pain, wound drainage, erythema, and development of additional wounds on the foot were found in equal number and severity between the treatment and control groups. Samuels et al performed a controlled piloted study on 20 subjects to determine the effect of low frequency, low intensity ultrasound on the treatment of venous stasis ulcers. All of the subjects in the low frequency, low intensity group demonstrated fully healed wounds by the fourth treatment session, demonstrating promising though not statistically significant support for the beneficial use of ultrasound in wound healing.  Maher et al determined from two case reports that the use of low frequency ultrasound may be beneficial to patients with chronic venous insufficiencies, finding a significant change in the amount of fibrin, periwound skin, drainage and wound color from initial treatment to final treatment. Slough filled wounds also decreased from 89% to 22% from initial to final treatments.

 

Procedure

The treatment guidelines outlined by Ennis et al will be utilized due to the strength and significance of findings in this study. Wounds will be irrigated with saline after a protective dressing is removed. New, sterile saline bottles will be attached to the transducer of the MIST therapy system ultrasound device set to an intensity of between 0.1-0.2 W/cm2. Ultrasound frequency will be set to 40 kHz. Treatments will last a period of 4-minutes for wounds measuring <15 cm2. The ultrasound device will be held perpendicular to the wound and moved in an up and down pattern across the wound bed. Treatment will continue at a frequency of once per week until the wound is healed.

 

Outcome Measures

With the goal of the treatment being to reduce open wounds and promote healing, outcomes will predominately lie in weekly documentation of wound size. A digital camera with a 1-inch marker frame can be used to determine wound size2.  Weekly wound evaluations will also include an assessment of wound exudation, periwound maceration, wound edge undermining, quantity and quality of granulation tissue, eschar, fibrin, and slough1.  Exudation and periwound maceration will be assessed and documented using a quantitative scale of “none”, “mild,” or “moderate” with descriptors of “serous” or “sero-sanguineous”1.  Granulation, fibrin, and eschar will be assessed as a whole and expressed as a percentage of the overall wound area1.  Callus formation and/or wound undermining will be documented with a “yes” or “no”.

 

References:

 

1. Ennis W, Foremann P, Mozen N, Massey J, Connor-Kerr T, Meneses P. Ultrasound therapy for recalcitrant diabetic foot ulcers: results of a randomized, multicenter study. Ostomy Wound Manage. 2005;51(8):24-39.

2. Samuels J, Weingarten M, Margolis D, Zubkov L, Sunny Y, Bawiec C, Conover D, Lewin P. Low-frequency (<100 kHz), low-intensity (<100 mW/cm(2)) ultrasound to treat venous ulcers: a human study and in vitro experiments. J Acoust Soc Am. 2013;134(2):1541-7.

3. Maher S, Halverson J, Misiewicz R, Reckling T, Smart O, Benton C, Schoenherr D. Low-frequency ultrasound for patients with lower leg ulcers due to chronic venous insufficiency: a report of two cases. Ostomy Wound Manage. 2014;60(2):52-61.