SUBMILLIMETER SHAPE ACCURACY USING FIBER OPTIC SHAPE SENSING IN SURGICAL APPLICATIONS

Shape Accuracy in Surgical Applications

In the world of surgical device navigation, the historical reliance on X-ray technology is undergoing a transformative shift fueled by the emergence of alternative navigation methods such as vision-based approaches, electromagnetic tracking, mechanical end effector tracking, and ultrasonic systems. These alternatives offer increased accuracy, improvements in real-time imaging, improved costs, size advantages, and reduced radiation exposure. While the emergence of alternative navigation methods has proven disruptive in medicine and various industries, significant limitations such as line of sight requirements, electromagnetic interference, and cumbersome workflows continue to be problematic in meeting the requirements for further adoption in operating rooms. Amidst these challenges, fiber optic shape sensing (FOSS) has emerged as an innovative technology that introduces solutions to many of the established limitations of conventional surgical navigation methods. The Shape Sensing Company’s (TSSC) shape sensing and navigation technology, leveraging the distinctive advantages of fiber optics, is poised to change the landscape of device guidance. Today, we aim to demonstrate that our shape sensing and navigation technology not only addresses the drawbacks of existing systems but also meets the strict accuracy requirements essential for a surgical device navigation system.

Shape Accuracy in Surigcal Applications

Fiber optic shape sensing involves a sensor consisting of either a multi-core fiber or a configuration of multiple single-core fibers, and an interrogation technique called Optical Frequency Domain Reflectometry (OFDR). These elements, in combination with TSSC’s processing algorithms, enable the 3D shape of the sensor to be measured and visualized. Fiber-based shape sensors are compact and flexible, they do not require line-of-sight, they provide real-time visualization of the entire sensor length, and are immune to electromagnetic interference. The concept of fiber optic shape sensing has been around for quite some time, however, limitations in sensing twist, spatial resolution, and cost have limited accuracy and adoption. Recent studies demonstrate attempts in artificial twist compensation, yielding average shape accuracy results in the range of approximately 1 mm, with some publications displaying submillimeter accuracy. However, these studies do not indicate realistic results that may be achieved outside of a tightly controlled laboratory setting, let alone in a device in the operating room. Current studies also illustrate the absence of standardized testing methods and error metrics, making comparison of different shape sensing solutions difficult or impossible. 

TSSC’s technology overcomes the limitations of existing shape sensing solutions. In contrast to these alternatives, it provides spatially continuous measurements along the entire sensor length with resolution down to a few 10s of microns, provides accurate, distributed twist sensing, and is on a path toward consumable pricing. Twist sensing has proven to be absolutely essential for shape sensing technology to maintain accuracy when used within devices such as endoscopes, catheters, and guidewires. TSSC’s technology has been rigorously tested under conditions that mirror its intended use in surgical environments, ensuring relevance and applicability.

In this study, TSSC is demonstrating 3D shape accuracy when our fiber sensor is inserted into a tortuous anatomical path. The test process includes…

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Submillimeter accuracy using fiber optic shape sensing in surgical applications – white paper