Biomedical Engineering Reference
In-Depth Information
6.2 Fluorescent microangiographs of angiogenesis into 6mm ECM discs
implanted subcutaneously in the mouse and evaluated at 21 days. Intact SIS
(a) shows actively growing (leaky) capillaries penetrating to a depth of nearly
3mm from disc edge, whereas the stripped SIS implants (c) showed much
fewer actively-branching capillaries and a penetration depth of less than 1mm
from disc edge. Further, note the difference in cellularity between the implants
with the intact SIS (b) showing significantly more cellularity than the stripped
SIS (d).
synthetic graft materials, many are not familiar at dealing with complications
that can be seen when biologic graft materials are utilized to restore tissue
function.
The idea that a biologic implant is simple to implant and use simply because
it is naturally derived has been the thought of surgeons in the recent past, but
experience in using biologic materials derived from human dermis and porcine
intestinal submucosa suggests that the more complex the implant, the more
difficult it is to implant without complications. Because biologic graft materials
are able to interact with the body, they do not act like inert synthetics. Close and
secure tissue approximation with healthy tissue is essential to ensuring that the
material is able to interact with the patient's surrounding tissues and become
repopulated with fibroblasts. If suture spacing is so great that relative motion can
occur between the graft and the patient tissue, the biologic graft will likely be
walled off or prematurely degraded and will not incorporate into the surrounding
tissues. Likewise, if the patient is in such ill-health or the adjacent tissues are so
diseased or necrotic that fibroblasts cannot migrate into the graft, the biomaterial
will not become incorporated but instead will act as an inert nidus for seroma
formation, wound dehiscence, or infection. Therefore, achieving success when
