Pocket-sized imaging device improves accuracy of epidural placement

Science Highlights
July 27, 2017

NIBIB Small Business Innovation Research grant drives device development

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.
Hand-held ultrasound device
The Accuro hand-held ultrasound device automates image interpretation of the lumbar spine for epidural needle placement. Source:  Rivanna™ Medical LLC
To accomplish either an epidural block or a lumbar puncture, doctors must insert a needle tip from the skin surface to precise spaces within the spine. Epidural blocks provide anesthetic to block pain in the lower half of the body during surgical procedures or, most commonly, to relieve a mother’s pain during childbirth. Lumbar punctures draw spinal fluid for disease diagnosis from the area around the spine called the subarachnoid space. 
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.” Re-insertions increase patient discomfort and the risk of complications, including incomplete anesthesia, headache, bleeding, back pain, and sometimes even paralysis. 
In a feasibility study published online on Feb. 22, 2017, in Investigative Radiology1, the researchers observed a group of three doctors who performed the calculations for needle placement in 68 patient cases. The needle procedure was not performed for the study. 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 achieved high accuracy in identifying lumbar spine landmarks, including the midline of the spine. They detected the midline of the spine in 94 percent of cases and the epidural space 94 percent of the time. The study was led by Mohamed Tiouririne, M.D., chief of obstetric anesthesiology at the University of Virginia.
“This is a nice example of the advantages that ultrasound brings to image-guided interventions,” said Steven Krosnick, M.D., director for NIBIB program in Image-Guided Interventions. 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.
“Aside from driving innovation in ultrasound bone imaging, this SBIR-funded project has validated the use of ultrasound guidance in improving epidural placement success rates,” said Todd Merchak, program specialist with NIBIB’s Office of Program Evaluation and Strategic Partnerships. “From the public health perspective, the product has the potential to reduce complications from a common medical procedure and improve the overall healthcare experience of the patient.”
Referring to the Small Business Innovation Research support from NIBIB, Mauldin said that NIBIB not only funded the culmination of the team’s work to bring the device to market, but also funded the two landmark studies that showed the device was safe and effective in a clinical setting, which has been important for initiating the adoption of the handheld ultrasound device by clinicians.
Screen shot and illustration of angle of hand-held ultrasound
Accuro device display shows anatomical features in the lumbar spine (left), and proper placement along lumbar spine (right). Source:  Rivanna™ Medical LLC
The research was supported in part by NIBIB award EB015232.
1. Imaging Performance of a Handheld Ultrasound System with Real-Time Computer-Aided Detection of Lumbar Spine Anatomy: A Feasibility Study. Tiouririne M, Dixon AJ, Mauldin FW Jr, Scalzo D, and Krishnaraj A. Invest Radiol. 2017 Feb 22; DOI: 10.1097/RLI.0000000000000361[Epub ahead of print].
— Lisa Smith, special to NIBIB

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