Biomedical Engineering Reference
In-Depth Information
13.4
PMMA cement has been required to cope with the mechanical
mismatch between the implant and the recipient bone, as shown in
this cadaver explant, which shows an osteoporotic bone too weak to
bear the load transmitted at the interface.
mechanical stability and compatibility with the recipient bone (Aboulafia
et al
., 2007).
Furthermore, PMMA has been applied as
in situ
drug delivery system for
antibiotics in cavities produced by osteomyelytis, a severe infectious process
which is difficult to eradicate (Kent
et al
., 2006). it has also been proposed
as a drug delivery system for anti-blastic drugs in the
in situ
therapy of
tumours affecting the bone (Greco
et al
., 1992).
More recently, PMMA has been used as a moldable material to cast
temporary spacers after the removal of failed joint prostheses which were
involved in an infectious process. in this case, PMMA is not required to
provide any kinematic performance but just to give a provisional congruence
to the joint ends, for the time required by drug therapy to control and
possibly eradicate the infection and, then, allow the following implantation
of a revision prosthesis.
A new application of PMMA comes from spinal surgery. With the technique
of vertebroplasty, a crushed vertebral body can be restored to its original
volume and its inner space can be filled with PMMA cement to assure
mechanical strength (Pitton
et al
., 2008).
