Biomedical Engineering Reference
In-Depth Information
materials. it does not have these common disadvantages, such as being concrete, visible
during activation of mimics muscles, and having a temporary effect. For what concerns the
skeletal tissue, for years we have used autologous bone grafts and cartilaginous tissues
similar to many prosthetic materials. They showed plastic phenomenon and they were easy
to infections and resorption instead of esthetic and functional aspects. In these years,
porous polyethylene results to be a suitable material for bony integration; it is easy to use
and has great reconstructive quality and low susceptibility to infections. A general problem
of the same biomaterials is a lack of visibility on conventional radiographs; they can be seen
using magnetic resonance imaging or computed tomography. These investigations are not
suitable for the frequent examinations, because magnetic resonance imaging is a high-priced
procedure and computed tomography has a high radiation dose. During the follow-up, we
encountered some difficulties for their radiotransparency; therefore, in our study, we used a
noninvasive technique such as ultrasonography (US) to estimate the filling conditions and
eventually to characterize an eventual pathologic process during the early phase. The aim of
this study was to examine the use of ultrasound imaging in detecting the changes in
biomaterials.
All patients were grouped according to different kinds of diseases: malformative
pathologies (patients with hemifacial microsomia), degenerative pathologies ( patients with
scleroderma and with Romberg syndrome), results of skull-facial traumas, and pure
aesthetic problems such as senile aclasia. They have been examined using US (in early and
late postsurgical courses) with a highresolution probe (7.5-13 MHz, Astro; Esaote Biomedica,
Genoa, Italy). The protocol of the study has foreseen almost 3 ultrasound controls; with a
variable follow-up of 7 days to 36 months. After 7 days ofimplantation, we made the first
ultrasound control.
Polyethylene porous, being a semirigid material that needs rigid interns fixture, decreased
migration and stabilization problems. The polyacrylamide is introduced as a gel. If it is not
well positioned, it could migrate. Integration and migration progress can be studied by US
investigations, such as object examination. Initially, in both treated groups, transplant may
show a light inflammatory state that will disappear in the succeeding days. Correct
evaluation to appraise for the stabilization of the materials is composed of evaluating
clinical and US parameters. The clinical parameters were as follows: the alteration absence
of the impending fabrics, the graft, the edema absence, manque´ mobilization, or migration
of the implantation. The US parameters were as follows: absence of massive harvests of
liquidate, inflammatory reactions of the surrounding fabrics, and good visualization of the
implantation and the surrounding tissue. With this worktop, we have been able to appraise
the diverged characteristics of the biomaterial and visualize the tissues reactions. In our
results porous polyetylene showed strong ecogenic features such as the bone and vanishing
margins; however, the implantation (like a titanium screw) appears as a reverberated
ultrasound bundle. We could evidence the stability of the biomaterials, namely, its
integration, eventual nearby tissue alterations, in the early and late phases. Therefore,
polyacrilamide appears anecogenous with a water-like aspect in the recent implants and
corpuscolated in the older ones. Sometimes, such as in connective tissue degenerative
pathologies (such as scleroderma) with an increase of the fibrotic component, we can
visualize more vacuolized structures not for a lack of fibrotic integration but for the
pathologic fibrotic beams. Although the implant seemed to be surrounded by a fibrotic
tissue envelope, US technique can be considered an excellent way to visualize the clinical
