Minimally invasive surgery is only “minimally” invasive if the tools used to perform it don’t damage surrounding tissue, but a surgeon needs to know where instruments are in order to reduce damage.
By Stephanie Soucheray
A long, thin needle enters a patient’s groin for surgery in the abdomen. A steerable needle snakes through a patient’s torso to find a tumor to biopsy, while another delivers targeted drug therapies.
As surgery is redefined by minimally invasive procedures using tools such as steerable needles, endoscopic scopes and catheters, doctors must continuously keep track of the devices in patients’ bodies.
Medical devices can easily damage a patient’s tissue, and now researchers at UNC-Chapel Hill and North Carolina State University have developed an algorithm that can help providers locate devices inside patients.
Ultrasounds and X-rays can help give doctors images of the devices. But when minimizing radiation exposure is a goal, many doctors have no idea how to best capture the image without excessive harm and radiation to the patient.
“These devices are so important for minimally invasive surgeries, but the challenge is to estimate the shape of them in the patient because they are so flexible and tend to bend and change shape,” explained Edgar Lobaton, an assistant professor of electrical and computer engineering at NC State.
Lobaton developed an algorithm with Jingua Fu, Luis G. Torres and Ron Alterovitz, all from UNC, that takes into account the surgical procedure, tool shape and placement in the body and tells practitioners the minimal amount of X-rays required to get an accurate image of the tool.
“If you don’t estimate the shape of these tools accurately, you can cause damage,” Lobaton said. “But since these surgeries and medical devices are becoming more and more popular, we need a way to track these devices. Our algorithm tells doctors where to take the image.”
Currently, surgeons rely on the cameras attached to scopes or 3D ultrasounds to track devices during surgeries. Lobaton said that while cameras are useful, 3D ultrasounds provide inaccurate and hazy images. MRIs can also be used during these surgeries, but are time consuming.
Lobaton said his research has produced a computer program that surgeons could use in practices, but first the research will be presented at the IEEE International Conference on Robotics and Automation, being held in Karlsruhe, Germany, on May 6.
“What we are presenting is an approach that allows you to select the best images,” said Lobaton. He said the algorithm has yet to be tested in animals.