A team of bioengineers supported through a Small Business Innovation Research grant from the National Institute of Biomedical Imaging and Bioengineering (NIBIB) has developed a pocket-sized, ultrasound imaging device to aid doctors in accurately placing needles into the lumbar, or lower, spine. The novel ultrasound system incorporates hardware and software, including a computer-aided detection algorithm to enhance bone discernment—which typically is poor with ultrasound—to navigate the lumbar anatomy.
Accuracy of needle placement for either procedure is paramount, but for many patients, including most obese patients, accurate placement of the needle is often not achieved on the first try. Doctors most often feel for spinal landmarks with their fingers prior to epidural needle placement. But since these landmarks are more difficult to detect in obese patients, it is more challenging for doctors to navigate a needle to deliver epidural anesthesia.
“The drawback is that needle insertions fail quite frequently,” said William Mauldin, Ph.D., chairman and CEO of Rivanna Medical LLC, makers of the Accuro® device. “Most of the time, a reinsertion is required.” Reinsertions increase patient discomfort and the risk of complications, including incomplete anesthesia, headache, bleeding, back pain, and sometimes even paralysis.
In a feasibility study, the researchers observed a group of three doctors who performed the calculations for needle placement in 68 patient cases. More than half the volunteers for the study had body-mass-index (BMI) scores of 30 or more, which is considered obese. The doctors using the ultrasound device detected the midline of the spine in 94 percent of cases and the epidural space 94 percent of the time.
Ultrasound imaging to detect the epidural space has been shown to improve success in placing epidural catheters, but has not been widely adopted previously because doctors performing the procedures don't necessarily have proficiency in ultrasound interpretation. The new device automatically detects the spinal midline and charts the depth and trajectory to the epidural space, so users can operate it with minimal training.