Injectable silicone rubber for ocular implantation after evisceration

PLOS ONE, Nov 2019

Objective 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. Methods 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.

A PDF file should load here. If you do not see its contents the file may be temporarily unavailable at the journal website or you do not have a PDF plug-in installed and enabled in your browser.

Alternatively, you can download the file locally and open with any standalone PDF reader:

https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0193448&type=printable

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)


This is a preview of a remote PDF: https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0193448&type=printable

Peng Fei Zheng, Qi Sheng You, Qian Li, Hong Yan Deng, Ian Y. H. Wong, Xiao Yan Peng. Injectable silicone rubber for ocular implantation after evisceration, PLOS ONE, 2018, Volume 13, Issue 3, DOI: 10.1371/journal.pone.0193448