Surgical Aid Detects Parathyroid Tissue in Real-Time

Surgical Aid Detects Parathyroid Tissue in Real-Time
New device aims to lower risk of damaging healthy glands.

A device designed to prevent accidental removal of parathyroid glands during surgery is gaining traction. PTeye – which employs a handheld probe – leverages tissue fluorescence to help distinguish parathyroid tissue.

The tech was developed by biomedical engineers at Vanderbilt University and recently earned FDA marketing approval (plus a 2019 R&D 100 award from R&D World Magazine). It offers improved surgical precision for patients undergoing head and neck surgeries, such as thyroidectomies and parathyroidectomies.

“About 20 million Americans have some form of thyroid disease, and more than 50,000 cases of thyroid cancer are diagnosed annually,” said Carmen Solórzano, M.D., chair of the Department of Surgery at Vanderbilt University Medical Center. “The PTeye system requires no contrast dye, can be used with normal operating room lighting, is non-invasive and has already proven to be very accurate.”

“The PTeye system requires no contrast dye, can be used with normal operating room lighting, is non-invasive and has already proven to be very accurate.”

A Persistent Challenge

Parathyroid glands are notoriously difficult to distinguish from other tissues during head and neck surgeries, Solórzano says.

In up to 20 percent of thyroid surgeries, healthy parathyroid glands are accidentally damaged or removed, leading to complications such as post-surgical hypocalcemia. Worse, a surgeon can remove a lymph node or thyroid tissue assuming it is a diseased parathyroid gland.

“Surgeons have relied mostly on their eye to find the parathyroid gland. Other available techniques like ultrasound or sestamibi scans tend to work only when the parathyroid is diseased,” said Anita Mahadevan-Jansen, Ph.D., Orrin H. Ingram Professor of Biomedical Engineering and director of the Vanderbilt Biophotonics Center. “For identifying normal parathyroid, there hasn’t been an effective technique, except the surgeon’s eye or biopsy.”

The PTeye System

Mahadevan-Jansen has spent more than a decade developing a better approach. Her foundational work at Vanderbilt was the inspiration for PTeye. “We are the first group to identify that near-infrared autofluorescence exists in parathyroid glands compared to all other tissues in the neck,” Mahadevan-Jansen explained.

PTeye works by delivering a laser beam to unidentified tissue through its handheld probe, detecting parathyroid autofluorescence. A read-out on its screen provides a binary output that guides surgeons, answering the simple question: “Is this parathyroid tissue or not?”

Video: Anita Mahadevan-Jansen Demonstrates the PTeye System

Mahadevan-Jansen emphasizes that unlike other systems, PTeye does not look for just diseased parathyroid. When the probe touches any parathyroid – healthy or otherwise –  it beeps to warn surgeons to proceed with caution.

Field Testing

PTeye prototypes accurately identified parathyroid glands 97 percent of the time. Mahadevan-Jansen’s team, including postdoctoral scholar Giju Thomas, Ph.D., has since refined PTeye’s user interface based on surgeon feedback, resulting in the PTeye now FDA-approved for marketing. The clinical device accurately detects parathyroid tissue even in ambient room lighting.

The researchers are now evaluating PTeye’s impact on surgery outcomes. Solórzano says they are beginning a clinical trial to further assess the benefit of the PTeye device during surgeries, and that several medical centers across the U.S. are expected to join a multisite study evaluating PTeye’s clinical performance.

Benefits to Surgeons

The researchers are hopeful the device could save OR time and patient costs. By providing immediate answers to surgeons, it skips costly frozen sections and mid-surgery consults. It may also prevent repeat surgeries necessitated by incomplete removal of diseased parathyroid.

Mahadevan-Jansen says PTeye is ideal for clinics performing at least 25 thyroid or 15 parathyroid surgeries a year.

“There are parts of the world where thyroid diseases are endemic, resulting in a high number of thyroidectomies each year,” she said. “You can imagine the impact of a device like this would be tremendous in those places.”

The researchers say surgeons’ interest in near-infrared autofluorescence “has considerably surged” in recent years. They anticipate newer device iterations to enter the market soon. Already, Mahadevan-Jansen’s work has inspired a second, similar device (Fluobeam®) that incorporates a camera.