(LR-033) Performance of Prevent, A Novel Negative Pressure Wound Therapy Filler on Contracture

Coleman Fleming, NA; Mitchell Greenberg, MBA, MEng – Associate Investigator, The Geneva Foundation; Joe Hilsman, MS – University of Georgia; Meera Dhodapkar, MD, MPH – resident, Orthopedics, The Mayo Clinic; Michael Shuler, NA; Brett Freedman, MD – Orthopedic Spine surgeon- Chair, Orthopedics, The Mayo Clinic

Introduction: Reticulated open cell foam (ROCF) or black foam (BF) has been the wound filler of choice for negative pressure wound therapy (NPWT) over the last three decades.  A novel, pliable, transparent, thermoplastic elastomer (TPE) dressing has been developed and FDA-cleared.  Macro-deformation/wound contraction is felt to be a clinically important feature of NPWT. 

Methods:

Three dorsal midline quarter specimens from standard land swine (~100kg) were utilized.  An elliptical (15cm x 7.5cm) shallow (~1cm) and deep (~3-4cm) excisional wound was created.  BF and the novel TPE dressing were cut to the same templated size.  Measurements at the central and mid-peripheral point on each side were obtained prior to negative pressure application (NP) and at 3 clinically relevant pressures (-50, -80 & -125mmHg).  A total of 36 trials were performed per experimental condition with a total of 108 trials.  Univariable analyses and multivariable linear regression were performed.

Results:

In both shallow and deep wounds, both TPE and BF demonstrated a statistically significant increase compared to no wound filler when controlling for position of measurement, pressure applied, and pre-NP width (p< 0.05) In deep wounds, TPE demonstrated more wound contracture than black foam sponge.  (p< 0.05)  The novel TPE resulted in similar (shallow) and improved (deep) wound macro-deformation compared to BF.  Other significant variables are higher NP, position in the wound (central versus peripheral), and the wound width prior to application of negative pressure.  Placement of BF increased the wound width (i.e. the opposite of wound contraction) once the drape was placed and prior to NP application. This wound expansion was not seen with the TPE dressing.

 

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Average Contraction*	-125mmHg	-80mmHg	-50mmHg
Shallow/Partial Thickness Wound (~ 1.0cm depth)
TPE	3.69	3.20	2.82
ROCF Foam	5.36	4.31	3.31
Deep/Full Thickness Wound (3.0 to 4.0cm depth)
TPE	6.91	5.16	4.89
ROCF Foam	5.36	4.31	3.31

 

Discussion:

The TPE may be associated with a statistically significant increase in wound contracture.  In shallow wounds, TPE and BF are associated with a statistically significant increase in wound contracture. Other variables which are significantly associated with greater degrees of wound contracture are higher negative pressure, position in the wound, and the wound width prior to application of negative pressure. This study shows that the novel TPE dressing produces a similar or greater amount of macro-deformation compared to traditional BF.