A novel bilayered expanded polytetrafluoroethylene glaucoma implant creates a permeable thin capsule independent of aqueous humor exposure

Abstract The purpose of these studies was to evaluate clinical, functional, and histopathological features of glaucoma drainage implants (GDIs) fabricated from novel, custom‐tailored expanded polytetrafluoroethylene (ePTFE). Implants of matching footprints were fabricated from silicone (Control) and...

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Main Authors: Amanda Kiely Bicket, Julia Szeto, Peter Roeber, Jeff Towler, Mitch Troutman, E. Randy Craven, Anup Khatana, Ike Ahmed, Harry Quigley, Pradeep Ramulu, Ian F. Pitha
Format: Article
Language:English
Published: Wiley 2021-01-01
Series:Bioengineering & Translational Medicine
Subjects:
Online Access:https://doi.org/10.1002/btm2.10179
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author Amanda Kiely Bicket
Julia Szeto
Peter Roeber
Jeff Towler
Mitch Troutman
E. Randy Craven
Anup Khatana
Ike Ahmed
Harry Quigley
Pradeep Ramulu
Ian F. Pitha
author_facet Amanda Kiely Bicket
Julia Szeto
Peter Roeber
Jeff Towler
Mitch Troutman
E. Randy Craven
Anup Khatana
Ike Ahmed
Harry Quigley
Pradeep Ramulu
Ian F. Pitha
author_sort Amanda Kiely Bicket
collection DOAJ
description Abstract The purpose of these studies was to evaluate clinical, functional, and histopathological features of glaucoma drainage implants (GDIs) fabricated from novel, custom‐tailored expanded polytetrafluoroethylene (ePTFE). Implants of matching footprints were fabricated from silicone (Control) and novel, bilayered ePTFE. ePTFE implants included: (a) one that inflated with aqueous humor (AH) (High), (b) one that inflated with a lower profile (Low), (c) an uninflated implant not connected to the anterior chamber (Flat), and (d) one filled with material that did not allow AH flow (Filled). All implants were placed in adult New Zealand White rabbits and followed over 1–3 months with clinical exams and intraocular pressure. The permeability of tissue capsules surrounding GDIs was assessed using constant‐flow perfusion with fluoresceinated saline at physiologic flow rates. After sacrifice, quantitative histopathological measures of capsule thickness were compared among devices, along with qualitative assessment of cellular infiltration and inflammation. Capsular thickness was significantly reduced in blebs over ePTFE (61.4 ± 53 μm) versus silicone implants (193.6 ± 53 μm, p = .0086). AH exposure did not significantly alter capsular thickness, as there was no significant difference between High and Filled (50.9 ± 29, p = .34) implants. Capsules around ePTFE implants demonstrated permeability with steady‐state pressure: flow relationships at physiologic flow rates and rapid pressure decay with flow cessation, while pressure in control blebs increased even at low flow rates and showed little decay. Perfused fluorescein dye appeared beyond the plate border only in ePTFE implants. ePTFE implants are associated with thinner, more permeable capsules compared to silicone implants simulating presently used devices.
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spelling doaj.art-85cf0634896d4e65a944cbbb914fcd272022-12-21T22:40:12ZengWileyBioengineering & Translational Medicine2380-67612021-01-0161n/an/a10.1002/btm2.10179A novel bilayered expanded polytetrafluoroethylene glaucoma implant creates a permeable thin capsule independent of aqueous humor exposureAmanda Kiely Bicket0Julia Szeto1Peter Roeber2Jeff Towler3Mitch Troutman4E. Randy Craven5Anup Khatana6Ike Ahmed7Harry Quigley8Pradeep Ramulu9Ian F. Pitha10Wilmer Eye Institute, Johns Hopkins University School of Medicine Baltimore Maryland USAWilmer Eye Institute, Johns Hopkins University School of Medicine Baltimore Maryland USAW.L. Gore & Associates Newark Delaware USAW.L. Gore & Associates Newark Delaware USAW.L. Gore & Associates Newark Delaware USAWilmer Eye Institute, Johns Hopkins University School of Medicine Baltimore Maryland USACincinnati Eye Institute Cincinnati Ohio USADepartment of Ophthalmology and Vision Sciences University of Toronto Toronto CanadaWilmer Eye Institute, Johns Hopkins University School of Medicine Baltimore Maryland USAWilmer Eye Institute, Johns Hopkins University School of Medicine Baltimore Maryland USAWilmer Eye Institute, Johns Hopkins University School of Medicine Baltimore Maryland USAAbstract The purpose of these studies was to evaluate clinical, functional, and histopathological features of glaucoma drainage implants (GDIs) fabricated from novel, custom‐tailored expanded polytetrafluoroethylene (ePTFE). Implants of matching footprints were fabricated from silicone (Control) and novel, bilayered ePTFE. ePTFE implants included: (a) one that inflated with aqueous humor (AH) (High), (b) one that inflated with a lower profile (Low), (c) an uninflated implant not connected to the anterior chamber (Flat), and (d) one filled with material that did not allow AH flow (Filled). All implants were placed in adult New Zealand White rabbits and followed over 1–3 months with clinical exams and intraocular pressure. The permeability of tissue capsules surrounding GDIs was assessed using constant‐flow perfusion with fluoresceinated saline at physiologic flow rates. After sacrifice, quantitative histopathological measures of capsule thickness were compared among devices, along with qualitative assessment of cellular infiltration and inflammation. Capsular thickness was significantly reduced in blebs over ePTFE (61.4 ± 53 μm) versus silicone implants (193.6 ± 53 μm, p = .0086). AH exposure did not significantly alter capsular thickness, as there was no significant difference between High and Filled (50.9 ± 29, p = .34) implants. Capsules around ePTFE implants demonstrated permeability with steady‐state pressure: flow relationships at physiologic flow rates and rapid pressure decay with flow cessation, while pressure in control blebs increased even at low flow rates and showed little decay. Perfused fluorescein dye appeared beyond the plate border only in ePTFE implants. ePTFE implants are associated with thinner, more permeable capsules compared to silicone implants simulating presently used devices.https://doi.org/10.1002/btm2.10179blebcapsuleexpanded polytetrafluoroethylene (ePTFE)fibrosisglaucomaglaucoma drainage implant (GDI)
spellingShingle Amanda Kiely Bicket
Julia Szeto
Peter Roeber
Jeff Towler
Mitch Troutman
E. Randy Craven
Anup Khatana
Ike Ahmed
Harry Quigley
Pradeep Ramulu
Ian F. Pitha
A novel bilayered expanded polytetrafluoroethylene glaucoma implant creates a permeable thin capsule independent of aqueous humor exposure
Bioengineering & Translational Medicine
bleb
capsule
expanded polytetrafluoroethylene (ePTFE)
fibrosis
glaucoma
glaucoma drainage implant (GDI)
title A novel bilayered expanded polytetrafluoroethylene glaucoma implant creates a permeable thin capsule independent of aqueous humor exposure
title_full A novel bilayered expanded polytetrafluoroethylene glaucoma implant creates a permeable thin capsule independent of aqueous humor exposure
title_fullStr A novel bilayered expanded polytetrafluoroethylene glaucoma implant creates a permeable thin capsule independent of aqueous humor exposure
title_full_unstemmed A novel bilayered expanded polytetrafluoroethylene glaucoma implant creates a permeable thin capsule independent of aqueous humor exposure
title_short A novel bilayered expanded polytetrafluoroethylene glaucoma implant creates a permeable thin capsule independent of aqueous humor exposure
title_sort novel bilayered expanded polytetrafluoroethylene glaucoma implant creates a permeable thin capsule independent of aqueous humor exposure
topic bleb
capsule
expanded polytetrafluoroethylene (ePTFE)
fibrosis
glaucoma
glaucoma drainage implant (GDI)
url https://doi.org/10.1002/btm2.10179
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