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Intraoperative optical coherence tomography (OCT) is becoming widely available, and its adoption is increasing, but improvements in the technology are needed to maximize its readiness for prime time, according to Justis P. Ehlers, MD.
Reviewed by Justis P. Ehlers, MD
Dr. EhlersIntraoperative optical coherence tomography (OCT) is becoming widely available, and its adoption is increasing, but improvements in the technology are needed to maximize its readiness for prime time, according to Justis P. Ehlers, MD.
“Current intraoperative OCT systems provide real-time and rapid static feedback on retinal and ophthalmic anatomy during surgery,” Dr. Ehlers said. “In select cases, this information clearly impacts surgical decision-making as well as surgical maneuvers. The development of microscope integration has significantly enhanced the efficiency and the workflow for the utilization of intraoperative OCT.”
Figure 1: Real-time intraoperative OCT feedback during membrane peeling with a diamond dusted membrane scraper. Visualization of the instrument-tissue interaction is achieved. (Images courtesy of Justis P. Ehlers, MD)
Dr. Ehlers is The Norman C. and Donna L. Harbert Endowed Chair for Ophthalmic Research at the Cole Eye Institute, Cleveland Clinic, Cleveland.
“Multiple studies have shown that it has promise for enhancing surgery in a variety of ways,” Dr. Ehlers added. “We will continue to work forward to advance intraoperative OCT to get it ready for tomorrow. However, there are still unmet needs.”
Current capabilities and performance
As of July 2017, there are three commercially available microscopes with integrated OCT systems cleared by the FDA. In addition to providing immediate feedback to surgeons, select systems offer Z-tracking with automatic signal detection and improved functionality.
“Extended range systems provide the opportunity for unique intraoperative visualization, such as viewing of vitreoretinal relationships in complex detachments,” Dr. Ehlers said. “Heads-up display systems allow us to see our surgical maneuvers while we are actually performing them.”
Figure 2: Intraoperative OCT during vitrectomy for proliferative diabetic retinopathy identifies multiple fibroavscular membranes and areas of space between the membranes and retina for safe dissection. (Image courtesy of Justis P. Ehlers, MD)
Evidence for benefits
Studies evaluating microscope-integrated OCT systems include an investigation from Cynthia Toth, MD, and researchers at Duke University, showing strong correlation to portable spectral domain OCT (SD-OCT) systems with a benefit for allowing visualization of surgical maneuvers without interrupting the procedure.
A study from Susanne Binder, MD, and colleagues in Austria showed that use of intraoperative OCT as an aid to membrane peeling might reduce the use of dyes. The researchers reported being able to complete the peeling without dyes in 40% of cases and found strong correspondence between the location staining by adjuvant dyes and location of membranes with intraoperative OCT in 94% of cases.
Reporting their experience using a commercially available intraoperative OCT system, Becker, et al. found that it provided additional information in 74% of cases involving the posterior segment and altered surgical decision-making 42% of the time.
At the Cleveland Clinic, the feasibility and utility of intraoperative OCT, using multiple systems, is being investigated in a large prospective study that to date had enrolled more than 1,000 eyes. Dr. Ehlers reported that analyses of its impact demonstrate that intraoperative OCT has altered decisions for multiple posterior segment procedures.
“In 22% of cases, intraoperative OCT revealed residual membranes requiring peeling in cases where the surgeon believed the peeling was previously complete,” Dr. Ehlers pointed out. “In 15% of cases, it allowed surgeons to avoid unnecessary maneuvers by confirming the peel was complete when the surgeon thought additional peeling was needed.”
The real-time imaging feedback from intraoperative OCT also was provided important insights during examination of the retinal periphery in terms of examining for retinal breaks, defining peripheral anomalies, and localizing pathology.
Preparing for the future
Before intraoperative OCT is ready for prime time, image acquisition needs to be faster and more efficient and image quality needs to be better and more consistent, said Dr. Ehlers.
Automated tracking to areas of interest is also needed and automated tracking to surgical instruments is also desirable. Other ongoing development work is focused on better intraoperative software packages, refinement of the surgical feedback platform to enhance the way the surgeon interacts with the technology, validation studies examining outcomes and establishing value, and creation of a reimbursement model.
Justis P. Ehlers, MD
This article is based on a presentation given by Dr. Ehlers at the 2017 Retina World Congress. Dr. Ehlers is a consultant for multiple companies that market intraoperative OCT. He also receives equipment support from Leica and Carl Zeiss Meditec and has patents licensed to Bioptigen.