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Fang et al. Negative pressure wound therapy for diabetic foot limb salvage

flow, reduced edema, promoted granulation tissue stresses the importance of infection control as a
formation, decreased number of microorganisms, determining factor for the success of NPWT.
and fewer endotoxins. [6-10] NPWT increases blood
flow through increased blood volume, velocity and In addition to observational studies, long-term data from
[6]
vascular diameter, which may help to restore arterial three non-PAD subjects allows comparison between
insufficiency in patients with PAD. Further actions subjects with and without PAD. The limb salvage rate
[6]
on angiogenesis and endothelial proliferation may was as expected lower in PAD than non-PAD subjects.
result in shortening of wound healing time in subjects However, in the current study, the mean number of
with DFU and PAD. Although the gold standard NPWT treatment days was 14.7 in the PAD group, as
treatments for PAD are angioplasty and surgery to compared to 30 days in the non-PAD group, which may
fully restore blood flow, NPWT may also play a role in be related to the lower number of NPWT applications
the wound healing process in patients with DFU and in the PAD group than in the non-PAD group. The
PAD by helping to achieve limb salvage. The length of prolonged treatment days in the non-PAD subjects may
treatment was not solely determined by the severity be attributed to their stagnant improvement. Since there
of vasculopathy. Both infection and associated are additional determinants, it cannot be concluded
comorbidities could prolong the hospitalization as that PAD is the sole cause for this unexpected result.
observed in non-PAD subjects in the current study. These determinants include other comorbidities such
as end stage renal disease, hypertension, stroke, and
Other studies regarding limb salvage treatment osteomyelitis, all of which were present in one of the
for DFU regard use of free flap surgery. Although non-PAD subjects. The number of lengthened treatment
free flaps have the advantage of covering a larger days may have been due to severe osteomyelitis,
wound area as compared to NPWT, there are still since most enrolled non-PAD subjects typically had an
some drawbacks. Aside from donor side morbidity infection of which the severity rendered standardized
and prolonged operation time, these patients usually moist wound therapy ineffective.
present with other comorbidities and a lack of
recipient vessels. Also, the free flap may not always As this study is preliminary with a limited number of
completely fill the wound, leaving a dead space and subjects in the non-PAD group, further studies with
undermining, which can in turn lead to recurrence or more subjects and higher power are urgently needed
wound dehiscence. Kallio et al. [23] reported in their to determine significance. Future studies may also
2015 study that free flaps required a treatment time include qualitative data including HbA1c, kidney
of 9 to 20 months, in correlation to the degree of function, hepatic function, hemoglobin, C-reactive
PAD. They also identified a limb amputation rate of protein, and current medications.
30% for a correctable ischemic artery, and 50% for
an uncorrectable ischemic artery in DFU patients In conclusion, patients with DFU and PAD possess
with PAD, suggesting that flap use is less desirable many additional comorbidities which limit their options
in patients with severe PAD. The limb salvage rate for reconstruction following repeated debridement.
for DFU with the use of NPWT ranges from 97-100% NPWT remains an effective method of treatment
in previous studies. [1,20] On the other hand, the free for DFU with PAD with a high percentage of limb
flap salvage rate range is 76-91%. [23-25] Further salvage. The limb salvage rate was not as high as
comparative case control studies between NPWT in prior studies of NPWT as their subjects were not
and free flaps would be useful in highlighting the exclusively patients with DFU and PAD. The main
advantages of each. reason for limb loss was intractable infection.

NPWT also had some limitations. Coverage of wounds Financial support and sponsorship
with the NPWT sponge makes wound observation and None.
infection detection difficult. Although Banwell et al. [10]
suggested that NTWT may provide better bacterial Conflicts of interest
clearance, Mouës et al. [26] and Weed et al. [27] have There are no conflicts of interest.
shown a constant bacterial concentration. In the
current study, there were 3 complications consisting of Patient consent
1 mortality due to sepsis and 2 uncontrolled infections
with 1 resulting in limb amputation. Because all 3 All patients gave informed consent prior to treatment.
failed cases had previously undergone PTA, the
lack of circulation was unlikely to have been the only Ethics approval
determining factor for limb salvage. Hence, this study The study was approved by the Institutional Review

382 Plastic and Aesthetic Research ¦ Volume 3 ¦ December 20, 2016