Abstract
Purpose :
The occurrence of iatrogenic retinal breaks (IRB) in pars plana vitrectomy (PPV) is a complication that compromises the overall efficacy of the surgery. A subset of IRB occurs when the retina (rather than the vitreous gel) is cut accidentally by the vitrector. We hypothesise the a smart vitrector, equipped by a fiber-based optical coherence tomography (OCT) sensor, can detect intraoperatively the onset of IRB and activate promptly a PPV machine response to prevent them. We developed such a system and performed PPV on pigs to validate it.
Methods :
We fabricated the smart vitrectors by attaching a miniaturised fiber-based OCT sensor (125 μm in diameter) on commercial vitrectors (25G). The OCT sensor was appropriately positioned to detect undesirable retina displacement towards the vitrector orifice (i.e., IRB onset). The smart vitrector was connected to a commercial vitrectomy machine as in standard PPV. We used a customized OCT machine and a built-in algorithm to process the intraoperative signal. The system response time to an IRB onset was measured and compared to that of the average surgeon. Finally, two surgeons validated its ability to prevent simulated IRB (i.e., vitrector manipulations aiming to “bite” attached or detached retina) by performing PPV in 2 two pigs. Note that the system requires no signal interpretation by the surgeons.
Results :
We found that the response time of the system (28.9 ± 6.5 ms) is 12-times faster compared to that reported for intraocular maneuvers performed by surgeons (p < 0.0001). We show that an additional 2-times improvement can be attained with minor technical modifications that require proprietary access to the vitrectomy machine that was used. Ex-vivo validation (porcine eyes) showed that the system prevents 78.95% (15/19) (95% CI: 54.43 – 93.95) of simulated IRB, while in-vivo validation showed that the system prevents or mitigates 70.37% (38/54) (95% CI: 56.39 – 82.02) of simulated IRB.
Conclusions :
Our results are consisted with the hypothesis that an OCT – sensor attached to the vitrector can prevent IRB by providing intraoperative feedback to the PPV machine. Importantly, the use of the smart vitrector with its safety mechanism requires no modifications of the established PPV procedure. It can mitigate a significant proportion of IRB and thus improve the overall efficacy of the surgery.
This is a 2021 ARVO Annual Meeting abstract.