Injectable silicone rubber for ocular implantation after evisceration
March
Injectable silicone rubber for ocular implantation after evisceration
Peng Fei Zheng 1 2 3
Qi Sheng You 1 3
Qian Li 1 2 3
Hong Yan Deng 0 1 3
Ian Y. H. Wong 1 3
Xiao Yan Peng 1 3
0 Beijing Stomatology Hospital, Capital Medical University , Beijing , China , 4 Department of Ophthalmology, University of Hong Kong , Hong Kong , Hong Kong
1 Funding: The project was partially supported by Beijing Talents Fund (2015000021223ZK22) and National Natural Science Foundation of China , No. 81400422
2 Department of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University , Beijing , China , 2 Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology and Visual Science Key Lab , Beijing , China
3 Editor: Sanjoy Bhattacharya, Bascom Palmer Eye Institute , UNITED STATES
-
Data Availability Statement: All relevant data are
within the paper and its Supporting Information
files.
Competing interests: The authors have declared
that no competing interests exist.
Objective
Methods
To investigate the usefulness of addition type liquid silicone rubber (ATLSR) as injectable
implant after evisceration to maintain the eyeball volume in an animal experiment.
Twelve adult New Zealand white rabbits were included. One eye of each rabbit was randomly
selected for evisceration with the fellow eye as control. ATLSR was injected to fill the eyeball
socket after evisceration. In vivo observation and photographs were performed up to 24
weeks post-op. Two rabbits were sacrificed respectively at post-operative week 1, 2, 4, 8, 12
and 24. After enucleation, the vertical, horizontal and sagittal diameters of the experimental
eyeballs were measured and compared with the control eyes. Histopathological studies were
performed to evaluate signs of inflammation.
Results
Cornea remained clear throughout the observation period despite mild epithelial edema and
neovascularization. Compared to the control eyes, the experimental eyes were significantly
smaller in vertical diameter (17.00±1.17 vs. 17.54±1.11 mm, P<0.001), but larger in sagittal
diameter (16.85±1.48 vs. 16.40±1.38 mm, P = 0.008), and had no significant difference in
horizontal diameter (17.49±1.53 vs. 17.64±1.21 mm, P = 0.34). Postoperative inflammation
was observed at one week after surgery, which peaked at 2±3 weeks, then regressed
gradually. At week 12 and week 24, most of the inflammatory cells disappeared with some
residual plasma cells and eosinophils.
Conclusion
Injectable addition type silicon rubber may be a good choice for ocular implantation after
evisceration, maintaining eyeball volume and cosmetically satisfactory when compared to
the fellow eye. Spontaneous regression of inflammation implied good biocompatibility for at
least 24 weeks.
1.0 Introduction
Removal of painful blind eyes, cosmetically unacceptable blind eyes, and medically uncontrolled
endophthalmitis as a result of severe trauma or disease can be accomplished by either
evisceration or enucleation [
1,2
]. Evisceration is faster, less complex, and associated with less disruption
of the surrounding orbital tissues, better maintenance of extraocular muscles motility, leading to
superior cosmetic and functional results [
3,4
]. An ocular implant is usually needed to restore the
orbit volume after evisceration or enucleation. Commonly used ocular implants are solid spheres
of different materials such as porous polyethylene or coralline hydroxyapatite [5±8]. Reported
complications include implant exposure, conjunctival thinning, discharge, implant infection and
post-enucleation/evisceration socket syndrome (PESS) [9±12]. Several surgical techniques have
been described to achieve better appearance and prosthesis motility as well as less complications
[13±15]. When possible, an ocular implant should preferably be placed in the cornea-scleral shell
after the removal of the ocular contents (in-situ placement), which in turn results in improved
appearance and prosthesis motility [
16
]. Evisceration with corneal sparing was achieved through
a relaxing sclerotomy incision and the implant would then be placed in the evisceration scleral
shell [
16
]. However, implanting a solid sphere of appropriate size is technically challenging: the
scleral cavity must be opened widely to accommodate the sphere during surgery, and it would be
difficult for the implant to fit in without an adequate coverage by the donor sclera. Liquefied
implants injected through small incisions may be an alternative when trying to avoid the
mentioned problems [
17
]. Silicone rubber, a well-tolerated biomaterial [
18,19
], is commonly used in
surgical implants. Addition type liquid silicone rubber (ATLSR) is composed of liquefied
monomer and catalyzer. When mixed with the catalyzer, the monomer cross-links, solidifies, rending
it easy to shape as well as physicochemically stable [20±22]. It has grown into a c (...truncated)