Based on CD31 staining, Masson’s trichrome staining and actin staining, this study demonstrates that patients with complicated diabetic foot ulcers treated with UAW debridement exhibit significantly improved cellular proliferation compared to patients receiving surgical debridement. We previously have proposed in a report from a closed panel meeting that increases in collagen, myofibroblasts and microvessel density following UAW debridement might result from the mechanical stimulation of neo-angiogenesis and fibroblasts at the wound site [4
]. To our knowledge, this is the first randomized controlled trial (RCT) that has evaluated cellular proliferation and dermal repair in DFUs being treated with UAW debridement compared to DFUs receiving surgical wound debridement. The effects of UAW on cellular proliferation and dermal repair that we have observed in our study have also been described in preclinical studies involving diabetic mice. Maan et al. [28
] found increased vascular endothelial growth factor, CD31 and stromal cell-derived factor 1 in the wound beds of noncontact, low frequency ultrasound-treated mice compared to controls. Likewise, Roper et al. [29
] concluded that ultrasound therapy restores healing to diabetic animals by activating fibroblasts.
A previous single-center, non-comparative study showed that UAW debridement helped combat biofilm reformation and reduce bioburden in neuroischemic DFUs with mild infection [6
]. In this study, patients did not receive systemic antibiotics and the authors found that mean bacterial load in wound tissue samples before and after wound debridement after treatment period was log 5.55 ± 0.91 CFU/g and log 4.59 ± 0.89 CFU/g, respectively (p
< 0.001). In the current study, we observed that bacteria load was significantly reduced in the UAW group compared to the surgical group (UAW group log 4.27 ± 0.3—day 0 to log 2.11 ± 0.8 CFU/g—day 42 vs. surgical group log 4.66 ± 1.21 CFU/g day 0 to 4.39 ± 1.24 CFU/g day 42; p
= 0.01). The main differences between the previous study and our current study were that our study population included patients with moderate infection and when necessary, these patients took empirical antibiotics that were selected according to IDSA guidelines [12
]. Further, antibiotics were switched when needed to target bacteria that were detected from deep tissue cultures [17
]. As such, systemic antibiotics likely promoted the reduction of bacterial loads observed in our study. Notwithstanding, the UAW groups had a lower proportion of patients that took antibiotics than the surgical group (n
= 2, 7.4% vs. n
= 12, 50%, p
= 0.001). Furthermore, we observed that after the treatment period (six weeks), Wollina scores improved in both groups, and the UAW group exhibited significant improvements in terms of periwound skin and exudate levels (see Table 2
). In this regard, our results are in agreement with the statement that UAW debridement is as effective as surgical debridement in removing bacteria while selectively removing affected tissue and protecting intact tissue at the wound site [6
]. Furthermore, similar rates of patients were healed after six months of follow-up in both groups. These results are consistent with a recent systematic review to compare the effect of UAW versus nonsurgical sharp debridement, where no difference in healing outcomes between both debridement treatments of diabetic foot ulcers was found [31
]. In our study population, the time it took for ulcers to heal was significantly shorter in the UAW group than in the surgical group. In a RCT by Michailidis et al. [32
], they observed faster healing in DFU patients receiving non-surgical sharps debridement versus patients receiving UAW debridement. However, their results are unable to be generalized due to the small sample size.
As previously mentioned, this is the first RCT to evaluate the effects of UAW debridement and surgical wound debridement on cellular proliferation and dermal repair in ulcers and demonstrate that UAW debridement significantly improves cellular proliferation compared to surgical debridement. Importantly, our study also demonstrated that UAW debridement is as effective as surgical debridement in removing affected tissue, protecting intact tissue at the wound site. As such, UAW debridement could be an effective alternative to surgical debridement when it is contraindicated or not available for use on patients with DFU. Our experience also indicates that UAW therapy is appropriate for serial debridement of DFU patients with poor vascular statuses (neuroischemic aetiologies), anticoagulants prescriptions, and deteriorating wound beds likely infected with biofilms [4
The main limitation of our study was the difference in baseline characteristics among groups of our study population, such us duration of diabetes diagnosis, glycated hemoglobin, Texas Classification or type of infection (mild/moderate infection) (see Table 1
). Further studies should include a more homogenous population in both groups to confirm our findings. We consider that future trials may also evaluate efficiency or cost-effectiveness of both treatments and the possibility of the spreading of solution and microbes (aerosols) that may occur during UAW debridement and how that may be affected depending on the flow intensity of the solution and the device used to contain the fluid.