Biomechanical Considerations of Patching Material for Posterior Scleral Reinforcement Surgery

Abstract

PurposeTo characterize biomechanical properties of genipin-crosslinked human dura mater as reinforcing material for posterior scleral reinforcement (PSR) and to compare it with crosslinked human sclera.MethodsDonor dura mater and sclera were crosslinked in the same optimized genipin solution. Resistance to enzyme degradation for both materials were investigated by exposing the materials to accelerated enzyme degrading. Elastic modulus and tensile strength were measured by biomechanics testing equipment. Crosslinked human dura mater was used as reinforcing patch in PSR on 57 adult pathologic myopic eyes. The patients were followed up for an average 3 years. The main outcome was eye globe axial length change and safety profile of the reinforcing material.ResultsCrosslinked dura mater demonstrated similar percentage weight loss to crosslinked sclera when exposed to enzymatic solution. Dura mater has higher density than sclera. The retaining elastic modulus after enzyme exposure was 72.02 MPa for crosslinked dura mater while 53.88 MPa for crosslinked sclera, 34% greater for crosslinked dura mater, P = 0.0186). At the end of 3 years follow-up, the mean globe axis of the surgery eyes was reduced by 1.29 mm (from 30.81 to 29.51 mm, P < 0.0001, paired t-test). Visual acuity (BCVA logMar) improved by 0.10 logMar unit which is an improvement of five letters (P = 0.0184, paired t-test). No material specific complication was noted.ConclusionCrosslinked human dura mater may be superior to crosslinked human sclera as reinforcing material for PSR to manage progression of high myopia. This material was well tolerated on human eye.

Clinical outcomes of posterior scleral reinforcement in Chinese high myopia children

“…With good biocompatibility and sufficient tensile strength, we chose the absorbable dural patch and covered the weak posterior pole of the sclera with minimal surgical procedures and tissue interference. The PSR performance can be improved by the patching material with strong resistance to enzyme degradation and high retaining mechanical strength 16 . In our study, the grafts were in place without infection or severe rejection.…”

Long-Term Outcomes of Anti-VEGF Therapy with and without Posterior Scleral Reinforcement on Myopic Maculopathy in mCNV Eyes

“…In addition, a previous study found that PSR slows myopia progression and signi cantly increases choroidal thickness and choroidal blood ow in high myopia patients. According to animal experiments, [17] the histopathological changes after posterior scleral reinforcement were divided into 4 phases: in ammatory reaction period, granuloma formation stage, angiogenesis stage, collagen berformation stage and connective tissue proliferative stage. The implanted sclera began the process of sclera repair via neovascularization 1 to 3 months after the surgery.…”

“…[16] Animal experiments showed that the implanted sclera can repair the sclera through neovascularization. [17] Neovascularization improves the nutritional status of the posterior pole and consequently visual function. Additionally, PSR can increase choroidal perfusion signi cantly in high myopia patients.…”

The feasibility and safety of biomaterials for posterior scleral reinforcement in rabbits

“…This variation may be due to different surgical materials and surgical techniques [6][7][8]. At present, allogeneic human sclera [7], human endocranium [9], xenogeneic bovine pericardium [10], freeze-dried dura, and synthetic materials [11] have all been explored as PSR materials. The human sclera is considered to be a relatively good source of material in terms of biomechanical characteristics and low immunogenicity [12].…”