Optical guide aims to keep orthopedic procedures on target

25 Feb 2016

Hebrew University's BioDesign program develops "optoelectronic drill" to improve surgery outcomes.

BendGuide's developers say the market could be worth $500m/year in the US alone.

Common orthopedic procedures, such as hip and pelvic fracture surgery as well as spinal fusion, require the accurate positioning of a thin metallic wire to guide the positioning of a fixating screw. However, the surgical procedure is often hampered by deflection, bending and even breakage of the guide-wire, which then requires repair while complicating and prolonging the recovery of patients.

To address this challenge, Prof. Liebergall, head of the Department of Orthopedic Surgery at Hadassah Medical Center, Jerusalem, Isreal, has partnered with a multidisciplinary team of medical doctors, along with engineering and business students, from the affiliated Hebrew University's BioDesign: Medical Innovation program.

The team has identified a solution: by creating a system that provides real-time indication of deflection or bending of the guide-wire, a surgeon will be able to adjust the procedure before damage occurs. The team has developed BendGuide, an opto-electronic drilling system that monitors and detects minute changes in guide-wire trajectory during surgery. It allows surgeons to correct drilling trajectories during the procedure itself. The system eliminates guide-wire bending or breakage and significantly reduces operation time while increasing safety.

“This is an elegant technological solution to a complex problem,” said Prof. Yaakov Nahmias, director of The Hebrew University’s Alexander Grass Center for Bioengineering and the BioDesign program. “The group model and proof-of-concept experiments showed they could detect even minuscule changes in guide-wire trajectory.”

BendGuide provides real-time indication of deflection of surgery guide-wire.

BendGuide uses a fiber bundle with a reflecting laser beam that enables detection of small deflections in wire trajectory. At a fully-aligned state, the beam power hits the center of the detector array. When deflected, mirror misalignment causes the power to spread differentially across the fiber bundle.

The market for computer-aided navigation systems for surgery is growing fast. The researchers estimate the potential market to be $500 million annually in the United States alone, where hip fracture fixation is performed on 258,000 patients and spinal fusion on 350,000 patients each year. They add that they expect BendGuide to become “an integral part of this market, which is expected to grow further with the aging population”.

The interdisciplinary team which developed BendGuide included Prof. Giora Weisz, M.D., Chairman of the cardiology department at Shaare Zedek Medical Center in Jerusalem; Hadar Shor, an MBA student at the Hebrew University’s Jerusalem School of Business Administration and a fund manager for Israel's Ministry of Economics; and Kuti Uliel and Michal Zimerman, graduate students at the Alexander Grass Center for Bioengineering.

The following video shows how the new fiber optic guide-wire enables surgeons to perform highly accurate hip fracture and spinal fusion surgery with minimal side effects.