THE INTEGRATIVE SURGICAL THEATER: Combining Intraoperative Optical Coherence Tomography and 3D Digital Visualization for Vitreoretinal Surgery in the DISCOVER Study

Abstract

Purpose: To evaluate the feasibility of integrating intraoperative optical coherence tomography (OCT) with a digital visualization platform for vitreoretinal surgery.

Methods: The DISCOVER study is a prospective study examining microscope-integrated intraoperative OCT across multiple prototypes and platforms. For this assessment, a microscope-integrated OCT platform was combined with a three-dimensional (3D) surgical visualization system to allow for digital display of the OCT data stream on the large immersive display. Intraoperative OCT scans were obtained at various surgical milestones that were directly overlaid to the surgical view in a 55-inch passive 3D 4K high-definition display. Surgeon feedback was obtained related to system performance and integration into the surgical procedures through a prespecified surgeon questionnaire.

Results: Seven eyes of seven subjects were identified. Clinical diagnosis included epiretinal membrane (n = 3), macular hole (2), symptomatic vitreous opacity (1), and proliferative vitreoretinopathy (1). Optical coherence tomography images were successfully obtained and displayed on the 4K screen in all cases. Intraoperative OCT images facilitated identification of subtle retinal alterations. Surgeons reported that the 4K screen seemed to provide improved visualization of the OCT data stream compared with the semitransparent ocular view. Surgeons were able to examine the OCT data on the 4K screen without reverting to the external display system of the microscope. The system provided a uniform surgical visualization experience for both the surgeon and the assistant. In addition, the digital platform allowed all surgical personnel to simultaneously view both the OCT and the surgical field. All eyes underwent uneventful vitrectomy without reverting to the conventional microscope. No intraoperative adverse events occurred.

Conclusion: Integration of OCT into the digital visualization system may enable unique opportunities for surgeon feedback of intraoperative diagnostics. The overlay of the OCT data onto the 4K monitor seemed to provide excellent visualization of OCT details. Further research is needed to compare the conventional microscope-based approach to the digital 3D screen approach in regards to intraoperative OCT.

Figure 1. A microscope integrated intraoperative OCT with a 3-D digital display system

(A) The microscope integrated intraoperative OCT platform (Rescan 700). Black arrow indicates microscope head. The microscope oculars are replaced with a dual digital video camera component of the 3-D digital visualization system (Ngenuity, yellow arrow). The aperture (iris diaphragm) can be adjusted by slider control switch (red arrow), the larger aperture (more light, shallower depth of field) is available when the slider is on the right side. (B, C) Heads-up display positioned approximately 1.5 m from the surgeon. External monitor of the microscope’s data management system is seen on the right. (D) View of the 3-D display monitor seen close to assistant’s position. Without passive polarized 3-D glasses, fundus view is an overlapping double-image, while intraoperative OCT scans are observed as single image.

Figure 2. Surgical view with intraoperative OCT of normal fovea captured from 2-D stream video recording

Normal foveal contour is observed in both horizontal and vertical OCT scans. Two examples are shown based on the length of OCT scan, standard length (A), and longer OCT scan (B). The length of OCT-scan is adjustable from 3 to 11 mm.

Figure 3. Surgical view with intraoperative OCT of fovea in a case with macular hole

Prior to internal limiting membrane (ILM) peeling, an intraoperative OCT scan is obtained. The surgical view (A) and OCT B-scan is provided (B). Following ILM peeling, the surgical view from the microscope data display shows the OCT aiming target (C) and the OCT B-scan demonstrates removal of the ILM with minimal material at the hole edge (white arrow, D). The digital overlay on the 3-D screen is also provided before ILM peeling (E) and following ILM peeling (F). In this case, indocyanine green staining was performed followed by ILM peeling with a membrane loop. Intraoperative OCT was utilized to confirm the completion of ILM peeling and to identify any microstructural alterations of the retina.

Figure 4. Intraoperative OCT and Digital Surgical Visualization Utilizing Contact Lens Visualization

The higher magnification and narrower field of view provides greater “black” space for the intraoperative OCT overlay, enhancing visualization of the OCT data. This figure demonstrates OCT visualization during membrane peeling and identification of membrane edge.

Figure 5. A successful utilization of intraoperative OCT for complex surgical pathology

(A) Funduscopic image of retinal detachment with severe proliferative vitreoretinopathy. Existence of subretinal membrane prevented retinal attachment. Application of peripheral circumferential diathermy is seen. (B) Funduscopic view following retinectomy and subretinal membrane removal. Perfluorocarbon liquid are infused to stabilize and flatten the retina. (C, D) Horizontal and vertical intraoperative OCT B-scans demonstrate reattachment of the posterior retina with subclinical subretinal fluid. Subtle residual focal membranes and diffuse retinal thickening are also delineated.