Defining the role of ab externo Xen gel stent in glaucomatous eyes with prior failed surgical intervention.

PURPOSE: To evaluate the safety and efficacy of Xen45 Gel stent (Xen; Allergan) in eyes that have failed prior surgical intervention, compared to traditional glaucoma drainage device (GDD) or continuous-wave cyclophotocoagulation (CPC). Since this population has low expected success rates with additional surgery, it is vital to compare to standard-of-care surgical options. METHODS: Retrospective, single-center, case-control study of ab externo transconjunctival Xen shunt in eyes that have previously undergone trabeculectomy and/or GDD surgery. Postoperative data were collected for 18 months. Failure was defined as no light perception, additional glaucoma surgery required, or intraocular pressure (IOP) of < 6 mmHg after 6 weeks postoperatively. RESULTS: Eighteen Xen eyes and 36 control eyes matched on both glaucoma type and previous glaucoma surgeries were included. Seventy-two percent had primary open angle glaucoma, 11% uveitic, 6% primary angle closure, 6% pseudoexfoliation, and 6% pigmentary glaucoma. Fifty-six percent of eyes in each group had prior trabeculectomy, 28% of Xen and 31% of control eyes had prior GDD, and 17% of Xen and 14% of control eyes had both. Baseline medicated IOP was lower in the Xen group (21.8 ± 7.2) compared to controls (27.5 ± 9.4, P = 0.043). The cumulative failure rate at year 1 was 17% for Xen and 20% for controls (P = 0.57). Mean survival time was 14.1 (± 1.5) months and 11.4 (± 0.6) months for controls. There was no difference in minor complication rates between groups (P = 0.65), but the Xen group had a significantly lower rate of serious complications (P = 0.043) defined as vision threatening or requiring surgical intervention in the operating room. When censored for additional glaucoma procedures, there were no differences at year 1 in IOP, change in IOP, number of IOP-lowering medications, or number of medications reduced from baseline. CONCLUSIONS: The Xen shunt provides a reasonable alternative to current standard of care, with a similar failure rate at year 1, with a noninferior IOP reduction compared to GDD and CPC, and a preferred safety profile.

Computational analysis of stresses acting on intermodular junctions in thoracic aortic endografts.

PURPOSE: To evaluate the biomechanical and hemodynamic forces acting on the intermodular junctions of a multi-component thoracic endograft and elucidate their influence on the development of type III endoleak due to disconnection of stent-graft segments. METHODS: Three-dimensional computer models of the thoracic aorta and a 4-component thoracic endograft were constructed using postoperative (baseline) and follow-up computed tomography (CT) data from a 69-year-old patient who developed type III endoleak 4 years after stent-graft placement. Computational fluid dynamics (CFD) techniques were used to quantitate the displacement forces acting on the device. The contact stresses between the different modules of the graft were then quantified using computational solid mechanics (CSM) techniques. Lastly, the intermodular junction frictional stability was evaluated using a Coulomb model. RESULTS: The CFD analysis revealed that curvature and length are key determinants of the displacement forces experienced by each endograft and that the first 2 modules were exposed to displacement forces acting in opposite directions in both the lateral and longitudinal axes. The CSM analysis revealed that the highest concentration of stresses occurred at the junction between the first and second modules of the device. Furthermore, the frictional analysis demonstrated that most of the surface area (53%) of this junction had unstable contact. The predicted critical zone of intermodular stress concentration and frictional instability matched the location of the type III endoleak observed in the 4-year follow-up CT image. CONCLUSION: The region of larger intermodular stresses and highest frictional instability correlated with the zone where a type III endoleak developed 4 years after thoracic stent-graft placement. Computational techniques can be helpful in evaluating the risk of endograft migration and potential for modular disconnection and may be useful in improving device placement strategies and endograft design.

Personalized pediatric ophthalmology: a case report.

The availability of genetic sequencing has given physicians a new tool for diagnosis and treatment of disease, and "personalized medicine" has become an increasingly common term in general but not in pediatric ophthalmology. We present a case of a toddler who developed ataxia, opsoclonus, myoclonus, and developmental regression following anesthesia for a common otolaryngology procedure. The child was found to have a variant in the MT-ND6 gene (m.14484T>C), most commonly associated with Leber hereditary optic neuropathy, despite a phenotype more closely resembling Leigh syndrome. The incongruence of phenotype and genotype prompted whole exome sequencing, which identified an unexpected intronic missense mutation in RB1 (1960+5G>A), with a 90% penetrance for retinoblastoma. Limited evaluation of the posterior pole in clinic did not identify any lesions, and the risks and benefits of examination under anesthesia were discussed among neurology, ophthalmology, and anesthesiology. We report the outcome of these discussions. The value and risks of personalized medicine are discussed.

Intraoperative Optical Coherence Tomography-Assisted Descemet Stripping Automated Endothelial Keratoplasty for Anterior Chamber Fibrous Ingrowth.

PURPOSE: Here, we present the first reported case of intraoperative optical coherence tomography (OCT)-assisted Descemet membrane stripping automated endothelial keratoplasty (DSAEK) in a patient with anterior segment fibrous ingrowth. METHODS: A 61-year-old woman with corneal edema and chronic angle-closure glaucoma secondary to fibrous ingrowth after 2 glaucoma shunt device implantations underwent dissection and removal of anterior chamber fibrous ingrowth and DSAEK. The surgical techniques using intraoperative OCT and outcome are described. RESULTS: Intraoperative OCT provided a clear dissection plane of the fibrous membranes in the anterior chamber and view of their relation to the iris and corneal endothelium, despite an opacified cornea. The placement of the donor lenticule and absence of interface fluid were also verified intraoperatively. The postoperative course was uncomplicated with satisfactory outcome. CONCLUSIONS: We conclude that intraoperative OCT is a useful tool during DSAEK surgery, particularly in complicated cases such as anterior segment fibrous ingrowth and significant corneal edema.

A pharmacological screening approach for discovery of neuroprotective compounds in ischemic stroke.

With the availability and ease of small molecule production and design continuing to improve, robust, high-throughput methods for screening are increasingly necessary to find pharmacologically relevant compounds amongst the masses of potential candidates. Here, we demonstrate that a primary oxygen glucose deprivation assay in primary cortical neurons followed by secondary assays (i.e. post-treatment protocol in organotypic hippocampal slice cultures and cortical neurons) can be used as a robust screen to identify neuroprotective compounds with potential therapeutic efficacy. In our screen about 50% of the compounds in a library of pharmacologically active compounds displayed some degree of neuroprotective activity if tested in a pre-treatment toxicity assay but just a few of these compounds, including Carbenoxolone, remained active when tested in a post-treatment protocol. When further examined, Carbenoxolone also led to a significant reduction in infarction size and neuronal damage in the ischemic penumbra when administered six hours post middle cerebral artery occlusion in rats. Pharmacological testing of Carbenoxolone-related compounds, acting by inhibition of 11-ß-hydroxysteroid dehydrogenase-1 (11ß-HSD1), gave rise to similarly potent in vivo neuroprotection. This indicates that the increase of intracellular glucocorticoid levels mediated by 11ß-HSD1 may be involved in the mechanism that exacerbates ischemic neuronal cell death, and inhibiting this enzyme could have potential therapeutic value for neuroprotective therapies in ischemic stroke and other neurodegenerative disorders associated with neuronal injury.