Some PMMA related research and data. Have a look:
onlinelibrary.wiley.com/doi/10.1111/j.1524-4725.2009.01216.x/abstract (positive)
www.dralaindansereau.com/art_ref/article_2.pdf (positive)
www.abme.com.br/pdfs/Granuloma%20tardio.pdf (2003 article. Quite negative: please see excerpt below)
In recent years, several reports have described adverse
effects such as painful and disfiguring granulomatous
skin lesions weeks or even years after implantation
of PMMA microspheres.10-12 According to these case reports,
unsatisfactory cosmetic effects or visible, painful
nodules led to excision of the material. Subsequent histopathologic
and ultrastructural examination showed the
distinctive aspects of multinucleated foreign body giant
cells, which enclose round and sharply circumscribed,
translucent, nonbirefringent bodies that apparently correspond
to the implanted PMMA pearls. In addition, epithelioid
cells and a sparse lymphocytic infiltrate were
found surrounding these bodies embedded in a loose sclerotic
stroma.12
Similiar histologic findings were detected in the biopsy
specimen of our patient’s forehead (Figure 2). In
addition, the ultrastructural examination revealed microspheres
within the cytoplasm of giant cells and smaller
particles within the macrophages, which led to the supposition
of degradation (Figure 3). The histologic and
ultrastructural alterations were detected in the middle and
lower dermis as well as in deeper layers of the subcutis.
Several explanations for the occurrence of these nodules
have been considered, but the exact reason for a
granulomatous host response is still unknown. Some authors
interpret foreign body granulomas as a low-grade
chronic inflammation in the sense of a usual second response
to implantation, which would be clinically invisible
after strictly subdermal injection and only accidentally
diagnosed by histologic examination.12,13 In addition,
superficial intradermal implantation itself may lead to
granulomas.2,3 Furthermore, undesired dislocation of the
subdermally localized implant to more superficial skin
parts—especially of the forehead because of its frequent
muscle movement—should be discussed. Investigations
of intradermal models of guinea pigs demonstrated
transepidermal elimination that began as a movement of
thePMMAbeads toward the epidermis.3 Particle size analyses
in the same study indicated that some of the PMMA
particles were smaller than 35 µm in diameter and consequently
susceptible to phagocytosis and migration. The
presumption that degradation of the microspheres due to
local enzymatic activity or aggressive metabolites causes
foreign body granulomas requires further, predominantly
long-term, investigations. In addition, there may
be a correlation between the quantity of the implanted material
and the incidence of foreign body granulomas, as also
reported for augmentation with silicone fluid.14,15
Even if true granuloma formation after implantation
of PMMA is not very frequent, a reliable and easily
tolerated treatment is urgently needed. Intralesional injection
of long-lasting crystalline corticosteroid usually
has been the treatment of choice,16 but severe granulomas
occasionally require surgical excision.