Medical Policy

This document addresses the use of low-frequency, non-contact, non-thermal ultrasound therapy for wound management.

Note: Please see the following related document for additional information:

• CG-DME-48 Vacuum Assisted Wound Therapy in the Outpatient Setting
• CG-MED-71 Chronic Wound Care in the Home or Outpatient Setting

Note: For a high-level overview of this document, please see “Summary for Members and Families” below.

Investigational and Not Medically Necessary:

Use of low-frequency, non-contact, non-thermal, ultrasound therapy is considered investigational and not medically necessary for all applications.

This document describes clinical studies and expert recommendations, and explains why the use of low-frequency, non-contact, non-thermal, ultrasound therapy is not clinically appropriate. The following summary does not replace the medical necessity criteria or other information in this document. The summary may not contain all of the relevant criteria or information. This summary is not medical advice. Please check with your healthcare provider for any advice about your health.

Key Information

Low-frequency, non-contact, non-thermal ultrasound therapy is a wound treatment. It sends sound wave energy through a saline mist to the wound. The device does not touch the wound, and it does not use heat. It has been studied as an added treatment for skin wounds that are hard to heal, such as diabetic foot ulcers, venous leg ulcers, and other open wounds. The goal is to help clean the wound and support healing.

What the Studies Show

Low-frequency, non-contact, non-thermal ultrasound therapy is not clinically appropriate for any use because it has not been proven to improve health. Studies have not shown enough clear proof that this treatment leads to better overall wound healing than standard wound care.

Some studies showed possible benefits, such as smaller wounds or faster healing. However, many studies had problems that limit the ability of the results to be used outside the study setting, including inclusion of too few people, short follow-up, lack of blinding, or use of wound size change instead of rate of full wound healing. Better studies are needed to know if low-frequency, non-contact, non-thermal ultrasound therapy improves health.

Is this Clinically Appropriate?

Because this treatment is unproven, it may lead to care that does not help. Unnecessary or unproven treatments can lead to treatment that does not help.

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 Summary

Current published literature does not materially prove the use of low-frequency, non-contact ultrasound for the treatment of wounds improves net health outcomes. There is a lack of studies reporting complete wound healing as the primary outcome. Varying outcomes, study methodologies, devices, and treatment protocols make it difficult to generalize the findings of the current literature.

Discussion

Low-frequency, non-contact, non-thermal ultrasound has been proposed as an adjunctive wound therapy. The technology delivers ultrasound energy through a saline mist without direct wound contact and is hypothesized to promote healing by facilitating wound cleansing and debridement, reducing bioburden, stimulating angiogenesis and cellular activity, and improving the wound-healing environment.

Ennis and colleagues (2005) conducted a prospective, multicenter, randomized, double-blinded, sham-controlled, trial of 133 participants with recalcitrant diabetic foot ulcers. Among the133 randomized participants, 78 were lost to follow-up during the study for various reasons, leaving 55 participants available for the final evaluation. At 12 weeks, complete healing occurred more frequently with ultrasound therapy than sham treatment (40.7% vs. 14.3%; p=0.0366). Adverse-event rates were similar between groups. Strengths included randomization, blinding, sham control, and multicenter participation. Limitations included substantial attrition, protocol violations related to device administration, and comparison with sham treatment rather than an active wound-care alternative.

In a prospective, randomized controlled trial, Kavros and colleagues (2007a) assigned 35 individuals with non-healing leg and foot ulcers due to chronic critical limb ischemia to standard wound care, and another 35 to standard care plus low-frequency, non-contact, non-thermal ultrasound therapy. After 12 weeks, there were 22/35 participants who achieved greater than 50% wound healing in the ultrasound group and 10/35 participants who achieved greater than 50% wound healing in the standard care only group. Strengths included randomization and use of a concurrent control group. Limitations included small sample size, open-label design, reliance on surrogate healing measures rather than complete closure, and lack of member-centered outcomes.

Another study by Kavros (2007b) reported a single-center, open-label, nonrandomized, baseline-controlled case series of 51 individuals with chronic non-healing wounds of the lower leg or foot. Mean wound volume reduction improved 37.3% ± 18.6% in the standard of care group and was 94.9% ± 9.8% during the ultrasound therapy period. There was no wound closure noted during the baseline standard care period. Strengths included evaluation of a difficult-to-treat population and within-subject comparison. Major limitations included the absence of randomization, lack of a concurrent control group, potential temporal and measurement bias, and susceptibility to confounding.

In 2014, Beheshti randomized 90 individuals with venous leg ulcers to compression therapy alone, compression plus high-frequency ultrasound, or compression plus low-frequency non-contact ultrasound. Both ultrasound groups demonstrated shorter healing times and greater improvements in pain, edema, and ulcer size than compression therapy alone. However, no statistically significant differences were observed between the two ultrasound modalities, and recurrence rates were similar across groups. Strengths included randomized allocation and evaluation of complete healing. Limitations included modest sample size, lack of blinding, and inability to determine whether low-frequency ultrasound provides incremental benefit compared with another active ultrasound modality.

A 2015 industry-sponsored randomized, controlled trial by Gibbons compared the use of non-contact, low-frequency ultrasound and standard care to standard care alone for the treatment of chronic venous leg ulcers. Participants received treatment for 4 weeks. Following a 2-week run-in period, 48 participants with ulcers that demonstrated less than 30% area reduction with standard care alone were randomized to receive standard care alone or to receive non-contact, low-frequency ultrasound in addition to standard care. Standard care consisted of wound cleansing, dressing change, compression, and debridement as needed. Participants in the ultrasound group received treatment 3 times per week for 4 weeks (a total of 12 sessions). The primary outcome was the mean percent reduction of ulcer area after 4 weeks of treatment. Mean ulcer area reduction was 61.6% in the ultrasound group compared to 45.0% in the standard care group. Interpretation of these findings is limited by several methodological concerns. The trial was terminated early because of slow enrollment and randomized only 48 participants, reducing statistical power and increasing uncertainty regarding treatment effects. Participants and treating clinicians were not blinded, and no sham ultrasound control was used, increasing the risk of performance and expectation bias for subjective outcomes such as pain and quality-of-life measures. In addition, the ultrasound group received substantially more treatment visits than the standard care group, making it difficult to distinguish the effects of ultrasound from the effects of increased clinical contact and monitoring. Finally, the primary endpoint was wound area reduction rather than complete ulcer healing. While the study suggests that adjunctive ultrasound may accelerate short-term wound area reduction, these limitations prevent firm conclusions regarding its effect on complete healing or overall clinical benefit.

Another industry-sponsored randomized, controlled trial compared non-contact, low-frequency ultrasound with standard care to standard care alone for split-thickness donor sites (Prather, 2015). In this study, 27 participants who completed the minimum required treatments (13 ultrasound and 14 standard care) were included in the primary analysis. Standard care consisted of wound cleansing followed by application of a hydrocolloid border and a transparent dressing. Participants assigned to the ultrasound group (n=16) received standard care and additional ultrasound treatment 5 consecutive days per week. Participants who remained hospitalized were evaluated daily for 14 days, then weekly for a total of 6 weeks after their graft procedure. The mean time to heal was 12.1 ± 6.0 days in the ultrasound group compared to 21.3 ± 14.7 days for those who received only standard care. At day 14, 92% of the ultrasound-treated donor sites had healed compared to 64% of donor sites treated with standard care alone. After 4 weeks of treatment, all ultrasound-treated donor sites were healed compared to 71% in the standard care group. Although healing outcomes favored ultrasound, interpretation is limited by the small sample size, lack of participant and provider blinding, additional treatment attention in the intervention group, baseline imbalances between groups, and short follow-up. While wound healing was confirmed by blinded photographic assessment, these methodological limitations reduce confidence in the magnitude and generalizability of the reported treatment effect.

In a 2019 randomized, double-blind, sham control, single-center study by Rastogi and colleagues, the authors reported on the efficacy of non-contact, low-frequency airborne ultrasound therapy in participants with neuropathic, clinically infected or noninfected diabetic foot ulcers. There were 60 participants enrolled in the study with 58 participants completing the study. The included participants had a foot ulcer of at least 2 cm² in size. The therapy duration was for 28 days; daily for an initial 6 days followed by twice a week for the next 3 weeks. Both study participants and investigators were blinded to the treatment as the ultrasound devices were coded by the manufacturers. The primary outcome measure was the percentage of participants with greater than 50% decrease in the ulcer area. Secondary outcomes were the percentage of participants with complete wound healing and percentage decrease in wound area at the end of the study. In the ultrasound therapy group, there was a greater than 50% reduction in wound area observed in 33 of 34 participants (97.1%). There were 8 participants (23.5%) who had a complete wound closure. The duration of the wound was 15.8 ± 11.2 weeks. One participant had less than 50% wound healing. In the sham group, there was a greater than 50% reduction in wound area observed in 19 of 26 participants (73.1%). There were 3 participants (11.5%) who had a complete wound closure. The duration of the wound was 12.1 ± 10.9 weeks. There were 7 participants who had less than 50% wound healing. There was a progressive reduction in wound size in both groups when compared to baseline. However, limitations of this study include the short follow-up period and single-center study design. The authors note that additional randomized, sham-control studies with longer follow-up times are needed to corroborate the results of this study with improvement in net health outcome.

A 2025 retrospective review by Gomez reported the efficacy of non-contact, low-frequency ultrasound in combination with standard treatment in the healing of fingertip amputations. The study included 18 participants with 19 treated fingertips, with 9 fingertips treated with non-contact, low-frequency ultrasound plus local wound care and 10 fingertips received only local wound care. Local wound care consisted of daily cleansing of the site with clean water followed by application of petroleum jelly, gauze, and tape. All individuals completed follow-up with no crossover between the two groups. The ultrasound group had a shorter mean time to healing (34.4±12.6 days) compared to 49.2 ± 17.6 days (p=0.053) in the local wound care only group; however, this difference did not reach statistical significance (p=0.053). Interpretation of the findings is limited by the retrospective, nonrandomized design, small sample size, and significant baseline differences in wound size between groups. In addition, participants receiving ultrasound had more frequent clinical visits, which may have improved adherence to local wound care independent of the ultrasound treatment.

In a 2017 systematic review by Chang and colleagues, the authors reported on 25 studies which examined efficacy of low-frequency ultrasound for wound debridement. While the authors noted that the use of low-frequency ultrasound as an adjunctive therapy in the treatment of chronic wounds is supported, the majority of the evidence is limited by study designs. In the articles reviewed, the authors noted eight different types of ultrasound debridement tools which led to uncertainty regarding the effectiveness and mechanism of action of each tool and the lack of well-designed clinical trials.

A 2023 meta-analysis by Chen and colleagues reported on the efficacy of low-frequency ultrasound as an added treatment for chronic wounds. There were 17 studies included. Studies were included if they were prospective, observational, randomized controlled trials, retrospective studies, and study participants had chronic wounds, with interventions based on low-frequency ultrasound, and compared the low-frequency ultrasound to standard care. Sample sizes ranged from 8 to 81 participants among the studies. From the studies, there were 412 participants who received low-frequency ultrasound and 187 of those participants received low-frequency, low-intensity non-contact ultrasound for venous leg wound ulcers compared to 193 participants who received sham treatment for venous leg wound ulcers. At greater than 3-month follow-up, those who received the low-frequency, low-intensity, non-contact ultrasound had significantly lower non-healed venous leg wound ulcers and a higher percentage of venous wound area reduction compared to those who received sham treatments. The authors note potential for selection bias due to studies excluded from the meta-analysis, small sample sizes, and lack of information whether the results were related to gender, age, and ethnicity. They advise the analysis of outcomes should be used with caution.

Wound healing is reportedly achieved by wound cleansing and maintenance debridement through the removal of yellow slough, fibrin, tissue exudates and bacteria. A saline mist is delivered to the wound via low-frequency non-contact ultrasound. The ultrasound device is indicated to promote wound healing without the use of a coupling gel or other direct contact. Potential risks to health that may be associated with these devices were identified by the United States Food and Drug Administration (FDA) as: delayed wound healing, thermal damage, inflammation/foreign body response, infection and electrical shock (FDA, 2005).

The device may consist of an equipment component (an ultrasonic generator and transducer) and a disposable component (sterile applicator). The sterile disposable applicator is attached to the generator’s transducer and has been designed to accept a pre-packaged sterile bottle of saline. Generally, treatment consists of three sessions per week, during which time the nurse or therapist holds the device near the wound while ultrasonic energy generated by the device atomizes the saline and delivers a continuous mist to the treatment site. The disposable applicator contains an on/off valve that controls the flow of sterile saline to the ultrasound transducer surface.

Several low-frequency non-contact ultrasound devices have been cleared by the FDA through the 510(k) marketing process; including UltraMIST^® (Sanuwave Health, Inc, Eden Prairie, MN),  Qoustic Wound Therapy System™ Device (Arobella Medical LLC, Minnetonka, MN), SonicOne^® (Bioventus^® Surgical, Durham, NC), and SONOCA™ (Quickborn, Germany).

Acute Wound: A wound with normal wound physiology anticipated to heal through the normal stages of wound healing; examples include lacerations, minor burns, and postoperative surgical incisions.

Chronic Wound: A wound that is physiologically impaired due to a disruption of the wound healing cycle, such as from impaired angiogenesis, innervation, or cellular migration; examples include nonhealing or infected surgical or traumatic wounds, venous ulcers, pressure ulcers, diabetic foot ulcers, and ischemic ulcers.

Non-contact low-frequency ultrasound: A technique to deliver low levels of ultrasound energy to the wound bed by means of the generated mist without direct contact of the device with the wound, thereby avoiding possible contamination.

The following codes for treatments and procedures applicable to this document are included below for informational purposes. Inclusion or exclusion of a procedure, diagnosis or device code(s) does not constitute or imply member coverage or provider reimbursement policy. Please refer to the member's contract benefits in effect at the time of service to determine coverage or non-coverage of these services as it applies to an individual member.

When services are Investigational and Not Medically Necessary:
For the following procedure code for all indications or when the code describes a procedure indicated in the Position Statement section as investigational and not medically necessary.

Peer Reviewed Publications:

1. Beheshti A, Shafigh Y, Parsa H, Zangivand AA. Comparison of high-frequency and MIST ultrasound therapy for the healing of venous leg ulcers. Adv Clin Exp Med. 2014; 23(6):969-975.
2. Bell AL, Cavorsi J. Noncontact ultrasound therapy for adjunctive treatment of nonhealing wounds: retrospective analysis. Phys Ther. 2008; 88(12):1517-1524.
3. Chang YR, Perry J, Cross K. Low-frequency ultrasound debridement in chronic wound healing: a systematic review of current evidence. Plast Surg (Oakv). 2017; 25(1):21-26.
4. Chen H, Yu Z, Liu N, et al. The efficacy of low-frequency ultrasound as an added treatment for chronic wounds: a meta-analysis. Int Wound J. 2023; 20(2):448-457.
5. Ennis WJ, Foremann P, Mozen N, et al. Ultrasound therapy for recalcitrant diabetic foot ulcers: results of a randomized double-blind controlled multicenter study. Ostomy Wound Manage. 2005; 51(8):24-39.
6. Ennis WJ, Valdes W, Gainer M, Meneses P. Evaluation of clinical effectiveness of MIST ultrasound therapy for the healing of chronic wounds. Adv Skin Wound Care. 2006; 19(8):437-446.
7. Gehling ML, Samies JH. The effect of noncontact, low-intensity, low-frequency therapeutic ultrasound on lower-extremity chronic wound pain: a retrospective chart review. Ostomy Wound Manage. 2007; 53(3):44-50.
8. Gibbons GW, Orgill DP, Serena TE, et al. A prospective, randomized, controlled trial comparing the effects of noncontact, low-frequency ultrasound to standard care in healing venous leg ulcers. Ostomy Wound Manage. 2015; 61(1):16-29.
9. Gomez RW, Walsh A, Valdes KG, Matullo KS. Enhancing healing with noncontact low-frequency ultrasound in fingertip amputation treatment: a comparative pilot study. J Hand Surg Glob Online. 2025; 8(1):100843.
10. Hinchliffe RJ, Valk GD, Apelqvist J, et al. A systematic review of the effectiveness of interventions to enhance the healing of chronic ulcers of the foot in diabetes. Diabetes Metab Res Rev. 2008; 24(Suppl 1):S119-S144.
11. Kavros SJ, Liedl DA, Boon AJ, et al. Expedited wound healing with noncontact, low-frequency ultrasound therapy in chronic wounds: a retrospective analysis. Adv Skin Wound Care. 2008; 21(9):416-423.
12. Kavros SJ, Miller JL, Hanna SW. Treatment of ischemic wounds with non-contact, low-frequency ultrasound: the Mayo Clinic experience, 2004-2006. Adv Skin Wound Care. 2007a; 20(4):221-226.
13. Kavros SJ, Schenck EC. Use of noncontact low-frequency ultrasound in the treatment of chronic foot and leg ulcerations: a 51-patient analysis. J Am Podiatr Med Assoc. 2007b; 97(2):95-101.
14. Keltie K, Reay CA, Bousfield DR, et al. Characterization of the ultrasound beam produced by the MIST therapy, wound healing system. Ultrasound Med Biol. 2013; 39(7):1233-1240.
15. Margolis D. The swings and roundabouts of randomized controlled studies in wound healing. Int J Low Extrem Wounds. 2004; 3(1):4-6.
16. Prather JL, Tummel EK, Patel AB, et al. Prospective randomized controlled trial comparing the effects of noncontact low-frequency ultrasound with standard care in healing split-thickness donor sites. J Am Coll Surg. 2015; 221(2):309-318.
17. Ramundo J, Gray M. Is ultrasonic mist therapy effective for debriding chronic wounds? J Wound Ostomy Continence Nurs. 2008; 35(6):579-583.
18. Rastogi A, Bhansali A, Ramachandran S. Efficacy and safety of low-frequency, noncontact airborne ultrasound therapy (Glybetac) for neuropathic diabetic foot ulcers: a randomized, double-blind, sham-control study. Int J Low Extrem Wounds. 2019; 18(1):81-88.
19. Samies J, Gehling M. Acoustic pressure wound therapy for management of mixed partial- and full-thickness burns in a rural wound center. Ostomy Wound Manage. 2008; 54(3):56-59.
20. Serena T. Wound closure and gradual involution of an infantile hemangioma using a noncontact, low-frequency ultrasound therapy. Ostomy Wound Manage. 2008; 54(2):68-71.
21. Voigt J, Wendelken M, Driver V, Alvarez OM. Low-frequency ultrasound (20-40 kHz) as an adjunctive therapy for chronic wound healing: a systematic review of the literature and meta-analysis of eight randomized controlled trials. Int J Low Extrem Wounds. 2011; 10(4):190-199.

Government Agency, Medical Society, and Other Authoritative Publications:

1. U.S. Food and Drug Administration 510(k) Premarket Notification Database. Celleration MIST Therapy System Summary of Safety and Effectiveness. No. K032378. Rockville, MD: FDA. June 25, 2004. No. K050129. May 2005. Available at: http://www.accessdata.fda.gov/cdrh_docs/pdf5/K050129.pdf. Accessed on July 16, 2026.

Qoustic Wound Therapy System
SonicOne
SONOCA
UltraMIST
Ultrasound, low-frequency wound therapy
Wound management, ultrasound MIST therapy

The use of specific product names is illustrative only. It is not intended to be a recommendation of one product over another, and is not intended to represent a complete listing of all products available.

Federal and State law, as well as contract language, including definitions and specific contract provisions/exclusions, take precedence over Medical Policy and must be considered first in determining eligibility for coverage. The member’s contract benefits in effect on the date that services are rendered must be used. Medical Policy, which addresses medical efficacy, should be considered before utilizing medical opinion in adjudication. Medical technology is constantly evolving, and we reserve the right to review and update Medical Policy periodically.

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