TABLE 1.
Summary of collected data in this scoping review
| Study author/year/country | Study design/participants | Wound type | Ultrasonic debridement device | Settings of ultrasonic debridement | Theme | Outcome related to bacteria/biofilm | Outcome related to wound healing | Conclusion |
|---|---|---|---|---|---|---|---|---|
| Breuing et al, 2005, USA 20 | Case study: N = 17 | Venous stasis ulcers (n = 5), arterial insufficiency–related ulcers (n = 2), diabetic ulcers (n = 3), pressure ulcers (n = 3), sickle cell anaemia (n = 1), and nonhealing surgical wounds (n = 4). | Söring Sonoca Ultrasonic Debridement Device, Sonoca 180 (Söring, Inc, Germany) | The ultrasonic amplitude is preferably set at 80– 100% and a frequency of 25 kHz. All wounds were treated for 20 seconds per cm2. | Wound healing, and bacterial existence after debridement with contact device. | In case 1, qualitative wound biopsy cultures grew 4+ MRSA, 4+ Stenotrophomonas maltophilia, and 4+ corynebacterium species before ultrasonic treatment. Final qualitative wound cultures grew 2+ MRSA only, and soft‐tissue biopsy showed granulation tissue after ultrasonic debridement.In case 2, qualitative wound biopsy cultures revealed 3+ E. coli, 2+ Serratia marcenscens, and 2+ β hemolytic streptococcus before ultrasonic debridement. Cultures taken after the initial ultrasonic treatment showed 1+ E. coli, 1+ β hemolytic streptococcus, and 2+ Serratia. | Nine of the wounds (53%) healed primarily or with the aid of a skin graft. Six additional patients (35%) experienced a wound‐size reduction of at least 50%. | Ultrasonic debridement has long been regarded as a technique that enhances wound healing. |
| Ennis et al, 2005, USA and Canada 21 | Prospective, randomised, double‐blinded, controlled, multicenter study: inclusion N = 133 (analysis N = 55) | DFU | MIST™ therapy system (Celleration Inc., Eden Prairie, MN) | A 4‐ minute treatment was conducted holding the device perpendicular to the wound bed and moving the device in an up‐and‐down pattern across the wound bed. Treatment times had been calculated as 4 minutes in duration for wounds measuring <15 cm2. | Proportion of wounds healed and adverse events after debridement with non‐contact device. | The initial, post‐debridement quantitative culture biopsies taken at enrollment showed that 86% of wound cultures in the group randomised to ultrasound treatment had >100 000 colonies/ g of tissue compared to 93% in the sham group. These differences were not statistically significant. | Overall, 40.7% of wounds in the ultrasound therapy, compared to 14.3% in the shamtreatment group, healed (P = .0366, Fisher's exact test). Time to healing differed significantly between the two treatment groups. | Ultrasound therapy is a useful adjunct to standard of care for the treatment of diabetic foot ulcers. |
| Escandon et al, 2012, USA 22 | A prospective pilot study: N = 10 (analysis samples for bacteria, n = 9) | VLU | MIST™ therapy system (Celleration Inc., Eden Prairie, MN) | The treatment time depended on the size of the wound that is set in the entry screen in the machine, for example for a wound size 10– 20 cm2 the irrigation time will be 4 minutes. The same physician operated the machine every time and placed the leading edge about 2 cm away from the wound. | Wound area, bacterial load, inflammatory cytokines profile, correlation between healing and cytokine expression change, and pain level after debridement with non‐contact device. | Staphylococcus aureus was the most prevalent species, being present in 9/ 9 samples, Pseudomonas aeruginosa was found in 6/ 9 samples and Kocuria kristinae was present in 5/ 9 samples. These last two bacteria had a reduction in their mean value, but this was not statistically significant in this group of patients. The overall bacterial profile was unchanged over the trial period. | Wound size mean area was 38.3 cm2 at the baseline, and it was reduced to 29.0 cm2 at last follow‐up visit. There was a statistically significant reduction (45% mean reduction) (P = .0039). | 1. Wound size reduction and decreased inflammatory cytokines expression were correlated despite a non‐significant decrease in bacterial count.2. Pain was decreased after treatment with non‐contact ultrasound and compression therapy in refractory venous leg ulcers. |
| Hiebert et al, 2016, USA 23 | RCT: N = 17 | Chronic open wounds of PU, DFU, and VLU. | Misonix low‐frequency ultrasound (SonicOne OR, Ultrasonic Debridement System, Misonix Inc., Farmingdale, NY) | Not described. | Wound closure and bacterial bioburden reduction after debridement with contact device. | Patients treated with hypochlorous acid irrigation showed sustained suppression of bacterial growth. However, patients treated with saline irrigation showed growth of bacteria to near predebridement levels at 7 days. | More than 80% of patients in the saline group had postoperative closure failure compared with 25% of patients in the hypochlorous acid group. |
1. Ultrasound debridement is an effective method to lower tissue bacterial counts in chronic wounds. 2. Hypochlorous acid is more effective than saline as an irrigant with ultrasonic debridement for maintaining wounds post–initial debridement until wound closure can be performed. |
| Esposito et al, 2017, Italy 24 | Cohort study: N = 32, n = 128 | Skin and soft tissue infections, including infected trophic ulcer (N = 16), infected post‐traumatic ulcer (N = 8), and diabetic foot infection ulcer (N = 8). | Ultrasonic debridement (Sonic One, Misonic, Inc) | About 5 min (average) at 5000– 7000 Hz. | Bacterial species isolated, percentages of concordance, and bacterial load after debridement with contact device. | Bacterial load yield by the culture of biopsy is significantly lower than that of a superficial swab after ultrasonic debridement. | Not described. | Ultrasonic debridement significantly reduced bacterial load or even suppressed bacterial growth. |
| Wiegand et al, 2017, Germany 25 | RCT: N = 36 | VLU | MIST™ therapy system (Celleration Inc., Eden Prairie, MN) | Subjects randomised to NLFU treatment continued with the standardised protocol of care plus NLFU therapy of 3 times per week for a total of 12 treatments. | Reduction of wound area, evaluation of bacteria population, and detection of mediator profiles after debridement with non‐contact device. | Peptoniphilus abundance significantly decreased more in the NLFU treatment group relative to standard of care for both swab (P = .007) and tissue biopsy samples (P = .01). The abundance of Proteus was found to decrease in both groups over the 4 week (P = .01). | Higher mean wound area reduction was observed in the NLFU treatment group (67.0%) compared to the control group receiving standard of care (41.6%) (P < .05). | NLFU improves wound healing by equally inhibiting abundant levels of proinflammatory cytokines as well as by reducing the overall bacterial burden. |
| Vallejo et al, 2018, Australia 26 | Case study: N = 4, n = 5 | VLU | low‐frequency ultrasonic debridement device, but the detailed information is not described. | LFUD was applied weekly in the clinic until it was deemed unnecessary. This was determined when the wound bed demonstrated signs of red, healthy granulation, an epithelial wound edge advancement and wound size reduction. | Biofilm suspected sign, bacterial existence, time to heal, pain level, and qualitative interview after debridement. |
1. The wound history and wound behaviour were also consistent with chronic wound infection and the presence of biofilm, which were presumptively diagnosed by the clinician. 2. These signs included: long duration of non‐healing; failure of multiple doses of antibiotic treatment to improve wound outcomes; persistent inflammation; regular presence of exudate; and unhealthy, friable granulation tissue. 3. Pseudomonas aeruginosa was diagnosed in all wounds via a swab culture prior to attending the clinic for all four participants. Additionally, Escherichia coli was identified in the wound of one patient. |
All of the wounds healed within 16 weeks. | Chronic wounds with suspected biofilm have the potential to heal if treatment is multifactorial. The combination of techniques used in case series was acceptable to patients and shows promise as an effective treatment, as it may have assisted the healing process. |
| Lázaro‐Martínez et al, 2018, Spain 27 | Case study: N = 24, n = 18 | DFU | SONOCA 185 device (Söring GmbH, Germany) | For most wounds, a two‐minute treatment with 40% intensity was performed by holding the sonotrode in contact mode, perpendicular to the wound bed, and moving it across in an up‐and‐down pattern. For wounds measuring >15cm2, the debridement procedure was increased to 3 minute. Ultrasound‐assisted wound debridement was conducted every week during a six‐week treatment period. | Wound size, wound bioburden, and correlation of reduced bacterial load after debridement with contact device. | The mean number of bacterial species per culture determined at week zero and at week six was 2.53 ± 1.55 and 1.90 ± 1.16, respectively (P = .023). Seventeen (70.9%) polymicrobial cultures at week zero versus seven (38.8%) at week six were observed (P < .001). | Wound healing progressed well, with significant wound surface area reductions observed during the treatment period. Mean wound sizes were 4.45 cm2 (range: 2– 12.25) at week zero, and 2.75 cm2 (range: 1.67– 10.70) at week six (P = .04). |
1. The process reduced bacterial load, thereby improving wound conditions and promoting healing. 2. Bacterial load reduction was independent to the bacterial species, with the ultrasound‐assisted wound debridement device acting in the same way against all bacteria, including antibiotic resistant bacteria strains. 3. Sequential wound debridement with an ultrasound‐assisted wound debridement device could avoid the unnecessary use of antimicrobials and reduce the risk of bacteria emerging with enhanced resistance levels. |
| Mori et al, 2019, Japan 28 | Study 1, cross‐sectional study: inclusion N = 67, n = 217 (analysis N = 48, n = 114); Study 2, retrospective cohort study: inclusion N = 77, n = 105 (analysis N = 65, n = 80). | Study 1, PU; Study 2, PU, DFU, VLU, and AU. | Qoustic Wound Therapy System (Arobella Medical, LLC, Minnetonka, MN) | Study 1: low‐frequency ultrasonic waves of 35 kHz and saline with 50– 100% of power levels using a 10‐ mm curette probe for 30 seconds to 2 minutes; Study 2: 60% power level for 1 to 10 minutes according to the size of the wound. | Study1: proportion of biofilm removal, and Study2: wound healing within 90 days after debridement with contact device. | Study1: proportion of biofilm removal; 38.9% (12.9– 68.0%) without ultrasonic debridement, 65.2% (41.1– 78.8%) with ultrasonic debridement, P = .009. | Study2: adjusted hazard ratio for the implementation of ultrasonic debridement in wound healing within 90 days, 4.5 (95% confidence interval, 1.3– 15.0; P = .015). |
1. Ultrasonic debridement was effective for removing biofilms of pressure ulcers. 2. The novel approach using biofilm‐based wound care system including both biofilm detection by wound blotting as a point‐of‐care testing and ultrasonic debridement can be a promising therapeutic strategy for promoting healing in chronic wounds. |
Abbreviations: AU, arterial ulcer; DFU, diabetic foot ulcer; N, number of patients; n, number of wounds; NLFU, non‐contact low‐frequency ultrasonic debridement; PU, pressure ulcer; VLU, venous leg ulcer.