Four-Dimensional Microscope-Integrated Optical Coherence Tomography Guidance in a Model Eye Subretinal Surgery

Abstract

Purpose: Subretinal delivery of stem cells and gene therapy vectors hold great promise in clinical care. Delivery techniques are evolving. We investigate the utility of 4-dimensional (volumes over time) microscope-integrated optical coherence tomography (4D-MIOCT) to guide such maneuvers. Methods: This investigational 4D-MIOCT system displayed heads-up cross-sectional and stereoscopic volumetric views through the microscope oculars at 3.3–10 volumes/second. In enucleated porcine eyes, we evaluated novel information available to the surgeon during subretinal: 1) injection of fluid and cell suspensions, 2) retinotomy creation, 3) insertion of membranes with a retinal pigment epithelium (RPE) cell monolayer and 4) subretinal instrument maneuvers, all in postmortem porcine eyes. Results: Interactions between tools, membranes, retina and RPE were often not detectable on the conventional microscope view but were obvious with 4D-MIOCT. 4D-MIOCT visualization was essential to: monitor the extent of induced retinal detachment, guide the cannula tip and instrument maneuvers in the subretinal space, and identify efflux of cells into the vitreous cavity. This allowed adjustment by the surgeon to avoid complications—e.g. scissors scraping RPE. Conclusions: 4D-MIOCT is useful for continuous monitoring of model subretinal surgery and may help avoid technique-related complications. 4D-MIOCT can contribute to the advancement of subretinal delivery of therapies under development.

What Is the Impact of Intraoperative Microscope-Integrated OCT in Ophthalmic Surgery? Relevant Applications and Outcomes. A Systematic Review

“…It is capable of recording live 3D images, which can be visualized directly into the surgeon’s oculars, providing a truly three-dimensional visualization of volumes in real-time using a novel dual-channel stereoscopic heads-up display. Some recent applications of 4D-MI-OCT are visualization of suture depth in strabismus surgery, evaluation of big-bubble formation in DALK, subretinal delivery of stem cells, and assessment of fibrovascular membranes and residual tractions in vitrectomy for proliferative diabetic retinopathy, especially in the cases of tractional retinal detachment, combined tractional-rhegmatogenous retinal detachment, and vitreous haemorrhage [ 122 , 123 , 124 , 125 , 126 , 127 ]. Moreover, 4D-MI-OCT has been used to perform transvitreal vitrectomy-assisted retinochoroidal biopsy in the case of uveal melanoma.…”

Controlled Subretinal Injection Pressure Prevents Damage in Pigs

“…Controlled injection systems for the administration of subretinal injections are already in use in clinical settings. The technique could be further advanced with robotic assistance to compensate for patient-/surgeon-related movements and intraoperative OCT guidance to optimize precision of the injection site [23, 24].…”