Optical guide will keep orthopedic procedures on target

A new fiber-optic guide-wire will enable surgeons to perform highly accurate hip and spine surgery with minimal side effects.

Fiber optics (photo credit: INGIMAGE)
Fiber optics
(photo credit: INGIMAGE)
A new fiber-optic guide-wire will enable surgeons to perform highly accurate hip and spine surgery with minimal side effects. In the US alone, hip fracture fixation is performed on nearly 260,000 patients a year, while there are also spinal fusion operations on 350,000 people every year. As the population ages, the number of these surgical procedures will surely continue to grow.
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, complicating and prolonging the recovery of patients.
“This is a significant challenge,” said Prof. Meir Liebergall, chairman of the orthopedic surgery department at the Hadassah University Medical Center in Jerusalem’s Ein Kerem, “as complications in guide-wire positioning could lead to revision surgeries and increase hospitalization time and cost.”
To do something about it, Liebergall joined a multidisciplinary team of medical doctors and engineering and business students from the Hebrew University’s BioDesign: Medical Innovation program. They identified a solution – by creating a system that provides real-time indication of deflection or bending of the wire, the surgeon will be able to adjust the procedure before damage occurs.
The team 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 and increases safety.
“This is an elegant technological solution to a complex problem,” said Prof. Yaakov Nahmias, director of HU’s Alexander Grass Center for Bioengineering and the BioDesign program. “The group model and proof-of-concept experiments showed they could detect even miniscule changes in guide-wire trajectory.”
BendGuide uses a fiber bundle with a reflecting laser beam that enables detection of small deflections in wire trajectory. In a fully-aligned state, the beam 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 potential market is estimated at $500 million annually in the US alone. BendGuide aims to become an integral part of this market, which is expected to grow further with the aging population.
How much you eat when you’re not really hungry may depend on how well off your family was when you were a child, according to new research published in Psychological Science.
“Our research shows that growing up poor promotes eating in the absence of hunger in adulthood, regardless of one’s wealth in adulthood,” said psychologist Sarah Hill of Texas Christian University. “These findings are important because they suggest that a person’s developmental history may play a key role in their relationship with food and weight management.”
Previous research has established childhood poverty as a risk factor for obesity, but the mechanisms driving this relationship are not completely clear. While a lack of access to healthy foods and safe places to play may help to explain the association, Hill and colleagues wondered whether early experiences might become biologically embedded in ways that shape how individuals regulate energy needs throughout one’s life.
Hill and colleagues recruited 31 undergraduate women to participate in what was purportedly a consumer research study. To rule out the potential effects of obesity and specific medical conditions, only women with a body mass index of less than 30 and those who did not have food allergies or diabetes were eligible to participate. The students received a bowl of chocolate chip cookies and a bowl of pretzels and were told to sample and rate each product. After completing their ratings, they were told that they were free to eat the leftovers while they waited for the next part of the study to begin.
They then completed a survey in which they were asked to think about their childhood before age 12 and rate their level of agreement with three statements: “My family had enough money for things growing up,” “I grew up in a relatively wealthy neighborhood,” “I felt relatively wealthy compared to others my age.”
After they finished, the researchers calculated how much the participants had eaten based on the food that remained in the two bowls.
Looking at the data for students who reported feeling relatively hungry, the researchers found no observable difference in calories consumed between those who grew up in more impoverished environments and those who grew in relatively abundant environments.
But childhood environment did seem to make a difference in how much people ate when they weren’t actually hungry. Students from relatively impoverished environments ate more of the pretzels and cookies, and more calories overall, than did those who came from wealthier backgrounds.
“We were surprised by the lasting impact that one’s childhood environment plays in guiding food intake in adulthood,” said Hill. “We were also surprised by the fact that one’s level of wealth in adulthood had almost no impact on patterns of food intake. Our research suggests that people who grew up in relatively impoverished environments may have a harder time controlling food intake and managing their body weight than those who grew up in wealthier environments,” Hill concluded.