Development of a biodegradable flow resisting polymer membrane for a novel glaucoma microstent

Siewert, Stefan; Falke, Karen; Luderer, Frank; Reske, Thomas; Schmidt, W. J.; Pfensig, Sylvia; Stiehm, Michael; Hinze, U.; Chichkov, Boris N.; Grabow, Niels; Guthoff, Rudolf; Schmitz, Klaus‐Peter

doi:10.1007/s10544-017-0218-8

Cited by 10 publications

(13 citation statements)

References 36 publications

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“…Initial flow resistance of the resorbable nonwoven (1.543 mmHg/µl min -1 ) conforms well with the target value of 1.850 mmHg/μl min -1 corresponding to a physiological aqueous humour flow rate of 2 µl min -1 and a physiological pressure difference between the anterior chamber of the eye and the suprachoroidal space of 3.7 mmHg [6]. Therefore, the risk of postoperative hypotony is minimized [5]. Chronosil 80A as base material of the drugeluting coating allows for a well-controlled drug release.…”

Section: Discussionmentioning

confidence: 56%

“…Resorbable nonwovens were manufactured from Poly(4hydroxybutyrate) (P(4HB); P4HB biopolymer, Tepha, Inc., Lexington, MA, USA) by means of electrospinning as described previously [5]. Process parameters of electrospinning are summarized in Table 1.…”

Section: Resorbable Nonwovenmentioning

confidence: 99%

“…Morphological analysis was performed using scanning electron microscopy (SEM; Quanta 250 FEG, FEI, Hillsboro, OR, USA). A test setup simulating in vivo pressure and flow conditions is used to analyze the volumetric flow rate as a function of the pressure difference for microstent prototypes [5].…”

Section: Resorbable Nonwovenmentioning

confidence: 99%

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Development of a drug-eluting microstent for micro-invasive glaucoma surgery

Siewert

Pfensig

Großmann

et al. 2018

Current Directions in Biomedical Engineering

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Glaucoma represents the leading cause of irreversible blindness worldwide. Therapeutic approaches are based on the lowering of intraocular pressure (IOP). Micro-invasive glaucoma surgery (MIGS) offers perspectives for implant based IOP-reduction with reduced complication rates compared to conventional surgical approaches. Nevertheless, available devices suffer from complications like hypotony and fibrotic encapsulation. The current work focuses on the development of a minimally invasive implantable drugeluting microstent for the drainage of aqueous humour into suprachoroidal or subconjunctival space. Technical feasibility of a micro-scale resorbable nonwoven for the prevention of hypotony and of a drug-eluting coating for the prevention of fibrosis is assessed. Microstent base bodies with a length of 10 mm and an inner/outer diameter of 0.20 mm / 0.35 mm were manufactured. For the prevention of hypotony, resorbable nonwovens with an adequate flow resistance of 1.543 mmHg/μl min-1 were manufactured in the inflow area of microstents. A drug-eluting coating in the outflow area of microstents was developed based on the model drug fluorescein diacetate. Micro-invasive ab interno implantation of a microstent prototype into suprachoroidal space of a porcine eye post mortem was successfully performed, using an injector device. Future studies will focus on the development of an antifibrotic drug-eluting coating and further in vitro, ex vivo and in vivo testing of the devices.

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Section: Discussionmentioning

confidence: 56%

Section: Resorbable Nonwovenmentioning

confidence: 99%

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Development of a drug-eluting microstent for micro-invasive glaucoma surgery

Siewert

Pfensig

Großmann

et al. 2018

Current Directions in Biomedical Engineering

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“…В качестве мер борьбы с указанными недостатка-ми применяется насыщение дренажей лекарственными препаратами [25], модификация формы [26] и поверхно-сти дренажей [20] или переход к резорбируемой основе [27]. Находясь в интрасклеральной полости в заданный временной интервал, резорбируемые дренажи способ-ствуют более совершенному формированию путей от-тока, тем самым пролонгируя гипотензивный эффект операции.…”

Section: Discussionunclassified

Experimental-Morphological Study of Several Types of Fibrillar Structured Drainages for Glaucoma Surgery

Khodzhaev¹,

Sidorova²,

Коломейцев³

et al. 2018

Ophthalmology in Russia

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Purpose: based on the results of an experimental study in vivo, to determine the optimal type of fibrillar structured drainages for glaucoma surgery.Material and methods. An experimental morphological study was performed on 32 rabbits of the chinchilla breed, which were divided into 4 groups of 8 animals each. The rabbits were implanted with fibrillar structured drains from polyurethane, polyethylene terephthalate, polyamide, polylactide. In the postoperative period, a postoperative inflammatory reaction was assessed. After removing the animals from the experiment, the eyes were subjected to morphological examination.Results. In rabbits with drainage from polyurethane, a mild congested hyperemia was noted in visual evaluation compared with the pair eye during the entire follow-up period. The eye reaction to the operation was regarded as a 1st degree. In more distant terms, there was a proliferation of subconjunctival tissue in the projection of the operation zone. In histological examination, the implant was represented by thin fibrous structures throughout the volume of drainage, a uniform distribution of macrophages, lymphocytes, among the fibers. In rabbits with drainage from polyethylene terephthalate, the reaction of the eyeball to the implantation of the polymeric material corresponded to the 0 degree. When a histological study was carried out along the periphery of the drainage, a thin capsule was formed. In rabbits with drainage from polyamide, the reaction of the eyeball corresponded to 1 degree. Histological examination showed that the fibrous structure of drainage was practically not determined, an abundance of cellular elements was observed throughout the drainage: macrophages and multinucleate giants predominated, fibroblasts, fibroblasts, lymphocytes, and newly formed connective tissue fibers between the drainage fibers were present. When analyzing the results obtained during the implantation of the matrix from the polylactide, the reaction of the eyeball corresponded to the 0 degree. Histological examination showed the preservation of fibrous structure of drainage, a moderate accumulation of macrophages was determined between the fibers, single giants, single lymphocytes were present.The conclusion. Fibrillar structured drains based on polylactide due to a stable highly porous structure, high biocompatibility and biodegradability create favorable conditions for transport of aqueous humor and formation of outflow pathways.

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“…Glaucoma is a major eye disorder causing irreversible blindness treated by important device inventions in industrialized countries [1][2][3]. In this research, basic concepts of adaptive implant for minimally invasive glaucoma treatment [4] were studied as shown in Fig.…”

Section: Introductionmentioning

confidence: 99%

Computational Fluid Dynamics Analysis of Titanium Outflow Pipe Implant for Glaucoma Treatment in Biomechanical Engineering

Karaçal

2019

Acta Phys. Pol. A

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Outflow pipe implant with check valve is a new glaucoma ocular tension treatment, developed primarily to correct the deteriorated intraocular fluid circulation in glaucoma disease. The research focus is to analyze a new outflow pipe implant with check valve material behavior for improving intraocular fluid outflow structure. Very few computational studies have considered both the mechanical and fluid flow impact of outflow pipe implant with check valve. There is non-available literature on outflow pipe implant with check valve structure and appropriate material selection to release the aqueous humor in intraocular stabilized pressure. The CFD-ANSYS simulation model was investigated for realization of realistic fluid flow velocity and pressure of aqueous humor behavior in microenvironment of the suprachoroidal space. The static structure and the von Mises stress for failure mode were studied to explore geometrical shape and material deformation structure by finite element method in ANSYS.Research results show affirmatively that structural analysis data correlates with fluid dynamics data in agreement.

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Development of a biodegradable flow resisting polymer membrane for a novel glaucoma microstent

Cited by 10 publications

References 36 publications

Development of a drug-eluting microstent for micro-invasive glaucoma surgery

Development of a drug-eluting microstent for micro-invasive glaucoma surgery

Experimental-Morphological Study of Several Types of Fibrillar Structured Drainages for Glaucoma Surgery

Computational Fluid Dynamics Analysis of Titanium Outflow Pipe Implant for Glaucoma Treatment in Biomechanical Engineering

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