Evisceration With Injectable Hydrogel Implant in a Rabbit Model

Koreen, Irina V.; McClintic, Elysa; Mott, Ryan T.; Stanton, Constance A.; Yeatts, R. Patrick

doi:10.1097/iop.0000000000000679

Cited by 4 publications

(3 citation statements)

References 13 publications

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“…[49][50][51][52] The aforementioned applications generally propose precursor solutions to exhibit low to no yield stress for injection through a high-gauge needle; however, low yield stress, paste-like hydrogel precursor solutions may be ideal for such applications because they allow for injection through higher gauge needles while providing benefits tailored to the application desired. [53][54][55] High yield stress, putty-like hydrogel solutions are generally useful in applications where shape fitting is required, such as craniofacial bone regeneration. [56,57] The higher yield stress precursor solutions and physical gels allow for better material shaping and directed tissue regeneration.…”

Section: Paste and Putty Applicationmentioning

confidence: 99%

Flow behavior prior to crosslinking: The need for precursor rheology for placement of hydrogels in medical applications and for 3D bioprinting

Townsend

Beck

Gehrke

et al. 2019

Progress in Polymer Science

158

102

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Hydrogels-water swollen cross-linked networks-have demonstrated considerable promise in tissue engineering and regenerative medicine applications. However, ambiguity over which rheological properties are needed to characterize these gels before crosslinking still exists. Most hydrogel research focuses on the performance of the hydrogel construct after implantation, but for clinical practice, and for related applications such as bioinks for 3D bioprinting, the behavior of the pre-gelled state is also critical. Therefore, the goal of this review is to emphasize the need for better rheological characterization of hydrogel precursor formulations, and standardized testing for surgical placement or 3D bioprinting. In particular, we consider engineering paste or putty precursor solutions (i.e., suspensions with a yield stress), and distinguish between these differences to ease the path to clinical translation. The connection between rheology and surgical application as well as how the use of paste and putty nomenclature can help to qualitatively identify material properties are explained. Quantitative rheological properties for defining materials as either pastes or putties are proposed to enable easier adoption to current methods. Specifically, the three-parameter Herschel-Bulkley model is proposed as a suitable model to correlate experimental data and provide a basis for meaningful comparison between different materials. This model combines a yield stress, the critical parameter distinguishing solutions from pastes (100-2000 Pa) and from putties (>2000 Pa), with power law fluid behavior once the yield stress is exceeded. Overall, successful implementation of paste or putty handling properties to the hydrogel precursor may minimize the surgeon-technology learning time and ultimately ease

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Section: Paste and Putty Applicationmentioning

confidence: 99%

Flow behavior prior to crosslinking: The need for precursor rheology for placement of hydrogels in medical applications and for 3D bioprinting

Townsend

Beck

Gehrke

et al. 2019

Progress in Polymer Science

158

102

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show abstract

“…Histological examination showed a decrease in granulomatous inflammation and an increase in vascularization of the implanted HA over the period with early osseous metaplasia. Koreen et al introduced 2.5% polyacrylamide hydrogel as an injectable ocular implant [ 23 ]. The relative diameters of the eviscerated eyes compared with control were 89 ± 6% (mean percentage ± standard deviation) at 12 weeks and 93 ± 4% at 1 year.…”

Section: 0 Discussionmentioning

confidence: 99%

Injectable silicone rubber for ocular implantation after evisceration

Zheng

You

et al. 2018

PLoS ONE

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ObjectiveTo investigate the usefulness of addition type liquid silicone rubber (ATLSR) as injectable implant after evisceration to maintain the eyeball volume in an animal experiment.MethodsTwelve 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.ResultsCornea 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.ConclusionInjectable 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.

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“…Blind and painful eyes due to end stage eye diseases, such as intractable glaucoma and endophthalmitis, can be treated surgically by evisceration. 1,2 The evisceration procedure removes the contents of the eye. The sclera is opened, and the intraocular contents are removed.…”

Section: Introductionmentioning

confidence: 99%

The application of an acellular dermal allograft (AlloDerm) for patients with insufficient conjunctiva during evisceration and implantation surgery

Park

Kim

Jang

2017

Eye

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PurposeTo describe the use of an acellular dermal allograft (AlloDerm) for patients with insufficient conjunctiva during evisceration and implantation surgery.Patients and methodsThe medical records of six patients with insufficient conjunctiva during evisceration surgery were reviewed. It was not possible to close the Tenon's capsule and conjunctiva without wound tension in these patients, so AlloDerm was placed over the sclera, and the edges were sutured with adjacent conjunctiva without tension. The size of the bare AlloDerm graft was measured in all patients. The clinical outcome was the incidence of complications, and the percentage of patients needing additional surgery was also recorded.ResultsThe cause of evisceration was end stage glaucoma (four patients) and endogenous endophthalmitis (two patients). All six eyes of six patients (100%) had a successful outcome showing no complications. Four cases achieved full conjunctivalisation over the bare AlloDerm graft. Two cases had a bare AlloDerm until the last follow-up, but showed no implant exposure. It took a median of 11 weeks for the slow advance of the conjunctival edge to entirely cover the AlloDerm graft.ConclusionsAlloDerm is a promising material for covering sclera and implants in a tension-free manner after evisceration surgery in patients with insufficient conjunctiva.

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Evisceration With Injectable Hydrogel Implant in a Rabbit Model

Cited by 4 publications

References 13 publications

Flow behavior prior to crosslinking: The need for precursor rheology for placement of hydrogels in medical applications and for 3D bioprinting

Flow behavior prior to crosslinking: The need for precursor rheology for placement of hydrogels in medical applications and for 3D bioprinting

Injectable silicone rubber for ocular implantation after evisceration

The application of an acellular dermal allograft (AlloDerm) for patients with insufficient conjunctiva during evisceration and implantation surgery

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