Sinus navigation systems have been around since the late 1980s. For many years, the systems were relatively basic; the monitors were low resolution and the instruments were relatively crude, noted Martin J. Citardi, MD, professor and chair of the department of otolaryngology–head and neck surgery at the University of Texas Health Science Center in Houston.
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April 2022However, in the past five years, several advancements in image-guided surgery (IGS) have increased the functionality of these systems, which are now enhanced by augmented and virtual reality technology.
“The newest systems are like a GPS system for the sinuses,” said Jivianne Lee, MD, associate professor in the department of head and neck surgery at the David Geffen School of Medicine at the University of California, Los Angeles.
Dr. Citardi agreed that significant advances have been made. “There are multiple [commercial] systems that are available now; competition has been very good at forcing innovation,” he said. (Dr. Citardi is a consultant for Acclarent and Intersect.)
Advances in Technology
One of the major advances in sinus navigation systems has been an improvement in instrumentation. All systems used in IGS have similar components: computer, workstation, video monitor, tracking system, surgical instrumentation, and data transfer hardware. Today’s models have high-resolution monitors that offer improved visualization and color contrast, especially in the red spectrum, which is essential for endoscopy of the sinuses.
According to Dr. Citardi, one of the foundations for reliable and accurate IGS is the registration process, a software-guided component that enhances the accuracy of the technology. “There’s a lot of discussion around instrumentation,” he said. “Each platform has a slightly different registration process, but getting registration right is essential for performing any of the advanced applications that are becoming possible.”
Most systems today use a contour-based registration protocol. The software automatically identifies the surface contour in the imaging dataset volume by building a 3D model from the computed tomography (CT) scan. At the time of surgery, the surgeon identifies contours on the surface of the patient’s face and head with a probe that’s tracked in 3D space. The software then aligns the contours mapped in the surgical volume with the corresponding contours in the preoperative imaging volume to create the registration. The system can also track the position of the patient’s head through a sensor/tracker that’s firmly attached to the patient’s forehead; this sensor allows the system to compensate for movement of the patient’s head during surgery (Ear Nose Throat J. 2021;100:NP475-NP486).