Biomedical Engineering Reference
In-Depth Information
0.0
0.1
0.2
Fresh dermis
T
m
: 61.3 ± 1.5 °C
∆
H
: 21.0 ± 2.3 J g
-1
Rehydrated AlloDerm
T
m
: 62.3 ± 0.8 °C
∆
H
: 21.1 ± 2.1 J g
-1
0.3
0.4
40
50
60
70
80
90
100
Temperature (°C)
10.9
Differential scanning calorimetric thermograms of AlloDerm RTM
(dashed curve) and fresh dermis (solid curve).
uniaxially until failure. Similar to the ultimate load data, the suture retention
strengths demonstrate a relatively broad range of values (~30-300 N) which again
correlate positively with tissue thickness (
Fig. 10.10b
). This data is consistent with
published independent studies (Derwin,
et al.
, 2006; Silver
et al.
, 2001) which
indicate the mechanical properties of RTM are comparable with that of native skin
dermis.
10.4 Functional evaluation
The characterization studies presented above provide evidence that the biochemi-
cal, structural and mechanical properties of native dermis are retained in the
processed RTM. The matrix template principle suggests that such properties will
afford the matrix the functional characteristics required of an RTM. This section
will address the preclinical and clinical evidence in support of the matrix template
principle by demonstrating the functionality of acellular RTMs.
10.4.1
Preclinical analysis of skin healing
The initial demonstration that preserved acellular dermal ECM scaffold could
function as an RTM during wound healing was performed in a full-thickness
excisional wound porcine model (Livesey
et al.
, 1995). Test wounds were treated
with allograft acellular RTM and a meshed STSG while control wounds received
STSG only. Histological assessment from biopsies taken at 16 days postgrafting
demonstrate uniform fibroblast infiltration, neovascularization, and an intact
stratified epithelium with the absence of an inflammatory response. Take rates of
