VISUAL OUTCOMES AFTER INTERNAL LIMITING MEMBRANE PEELING VERSUS FLAP IN THE CLOSURE OF FULL-THICKNESS MACULAR HOLES.

PURPOSE: To examine postoperative outcomes of internal limiting membrane peeling (ILMP) versus flap (ILMF) in the closure of full-thickness macular holes. METHODS: Retrospective chart review of patients who underwent pars plana vitrectomy and gas tamponade with ILMP or ILMF to close full-thickness macular hole at the Atrium Health Wake Forest Baptist from January 2012 to October 2022 with at least 3 months follow-up. Main outcome measures were type 1 primary full-thickness macular hole closure and postoperative best-corrected visual acuity in mean logMAR. RESULTS: One hundred thirty and 30 eyes underwent ILMP and ILMF, respectively. There were no significant differences in baseline characteristics between the groups. Ninety-six percent of ILMP eyes and 90% of ILMF eyes achieved primary hole closure ( P = 0.29). Among all eyes with primary hole closure, best-corrected visual acuity at 1 year was not different between the groups, but when stratified by lens status, it was superior in the ILMP versus ILMF group in pseudophakic eyes: the estimated least-squares mean best-corrected visual acuity (Snellen equivalent) (95% confidence interval) was 0.42 (20/50) (0.34, 0.49) in the ILMP group and 0.71 (20/100) (0.50, 0.92) in the ILMF group. CONCLUSION: Internal limiting membrane peeling and ILMF techniques yielded similarly high full-thickness macular hole closure rates. In pseudophakic eyes with primary hole closure, ILMF eyes had worse best-corrected visual acuity at 1 year.

A novel approach to sclerotomy closure in pars plana vitrectomy: a pilot study.

BACKGROUND: Methods of sclerotomy closure following a vitrectomy, including the use of sutures, have been associated with complications such as inflammation, foreign body sensation, and infection. Here, we test an innovative approach to scleral wound closure following pars plana vitrectomy that involves plugging the wound. We investigated several materials with the intent of using products that were either already approved by the FDA for other types of procedures or were biocompatible patient-derived materials. METHODS: We examined whether scleral wounds could be sealed by a clot or internal "plug" rather than a suture or an external adhesive. We tested patient-derived materials (platelet-rich plasma (PRP) and whole blood) as well as polyethylene glycol (PEG) sealant. Whole blood and PRP were prevented from clotting prematurely using sodium citrate, and were clotted for the study with thrombin. Polyethylene glycol (PEG) sealant was prepared according to manufacturer's recommendations. We used fresh-frozen cadaveric porcine eyes. We tested several methods to form plugs using the above materials, as well as various methods to deliver the plugs into the sclerotomy incisions. We used a novel technique of manual vitrectomy. Successfully generated and implanted clots were tested for efficacy with the Seidel test. RESULTS: Polyethylene glycol (PEG) sealant fractured during our attempts at molding and inserting the plug. In contrast, both whole blood and PRP yielded successful plugs for insertion. We molded a whole blood clot plug by allowing it to clot inside a 20-gauge angiocath catheter and we successfully delivered it through a 23G trocar. At baseline, no wound leakage was apparent. However, the whole blood clot dislodged during the Seidel test. We successfully molded and delivered a PRP clot plug using a tapered 2-20 µl pipette tip, using MAXGrip Forceps to push it through into the wound. No scleral wound leakage was noted at our baseline physiologic infusion pressure. Furthermore, the PRP clot plug prevented scleral wound leakage up to a pressure of 60 mmHg and was confirmed with the Seidel test. CONCLUSION: Our findings suggest that insertion of a clot plug made from either whole blood or PRP may be an effective strategy for scleral wound closure following pars plana vitrectomy. Further testing in preclinical models is warranted to further refine the materials and methods, since this appears to have the potential to improve the closure of the scleral wounds after pars plana vitrectomy.

Neurite orientation dispersion and density imaging reveals white matter and hippocampal microstructure changes produced by Interleukin-6 in the TgCRND8 mouse model of amyloidosis.

Extracellular ß-amyloid (Aß) plaque deposits and inflammatory immune activation are thought to alter various aspects of tissue microstructure, such as extracellular free water, fractional anisotropy and diffusivity, as well as the density and geometric arrangement of axonal processes. Quantifying these microstructural changes in Alzheimer's disease and related neurodegenerative dementias could serve to monitor or predict disease course. In the present study we used high-field diffusion magnetic resonance imaging (dMRI) to investigate the effects of Aß and inflammatory interleukin-6 (IL6), alone or in combination, on in vivo tissue microstructure in the TgCRND8 mouse model of Alzheimer's-type Aß deposition. TgCRND8 and non-transgenic (nTg) mice expressing brain-targeted IL6 or enhanced glial fibrillary protein (EGFP controls) were scanned at 8 months of age using a 2-shell, 54-gradient direction dMRI sequence at 11.1 T. Images were processed using the diffusion tensor imaging (DTI) model or the neurite orientation dispersion and density imaging (NODDI) model. DTI and NODDI processing in TgCRND8 mice revealed a microstructure pattern in white matter (WM) and hippocampus consistent with radial and longitudinal diffusivity deficits along with an increase in density and geometric complexity of axonal and dendritic processes. This included reduced FA, mean, axial and radial diffusivity, and increased orientation dispersion (ODI) and intracellular volume fraction (ICVF) measured in WM and hippocampus. IL6 produced a 'protective-like' effect on WM FA in TgCRND8 mice, observed as an increased FA that counteracted a reduction in FA observed with endogenous Aß production and accumulation. In addition, we found that ICVF and ODI had an inverse relationship with the functional connectome clustering coefficient. The relationship between NODDI and graph theory metrics suggests that currently unknown microstructure alterations in WM and hippocampus are associated with diminished functional network organization in the brain.