Performing epidural and spinal anesthesia requires a good deal of training and being able to sense when the needle reaches the desired location. This is certainly not foolproof and some patients are harder to work with than others. One issue is that a sonographer is usually required to operate the ultrasound while the anesthesiologist delivers the needle. Accuro, a new ultrasound device recently cleared by the FDA, offers capabilities that can alleviate a sonographer from having to help with epidurals and spinals. We wanted to learn more and took a chance to ask some question of Will Mauldin, CEO of Rivanna Medical, the Charlottesville, Virginia company that developed the Accuro.
Medgadget: Anesthesiologists typically have ready access to powerful, large-screen ultrasound devices with advanced capabilities. Can you explain how the Accuro makes epidurals easier to perform and what issues it was designed to solve? Can your device be used for spinals?
Will Mauldin: Despite having ready access to those powerful ultrasound devices, placements of neuraxial anesthesia, including epidurals and spinals, remains a “blind” technique guided only by the provider’s manual palpation skills and experience. As one might expect, this blind approach is troublesome especially in obese patients where landmarks are impalpable or in patients with spinal abnormalities such as stenosis or scoliosis. Meanwhile, numerous RCTs and meta-analysis have proven that ultrasound guidance can outperform manual palpation to produce improved success rates and patient safety.
So why the disparity between the clinical evidence and actual clinical practice? The reason is the very steep learning curve associated with conventional ultrasound. Studies showing benefits of neuraxial ultrasound guidance almost always rely on expert sonographer-level providers. Meanwhile numerous studies also show that the average anesthesia provider is not able to gain a basic level of competency to navigate the spine with ultrasound even after one-on-one training and hundreds of procedures.
The purpose of Accuro is to greatly reduce the training burden so that all providers can readily access the benefits of neuraxial ultrasound.
Medgadget: What are some of the prominent features of the device that help to guarantee proper needle insertion and localization of the epidural space?
Mauldin: The prohibitively steep learning curve associated with traditional ultrasound use for neuraxial anesthesia guidance is largely due to difficulties associated with ultrasound bone imaging. The general purpose ultrasound machines that anesthesiologists use today are excellent tools for visualizing soft tissue structures, such as blood vessels or nerves. However, bony anatomy images are completely different. The bone surface brightness is angle dependent and is notorious for generating imaging artifacts. For these reasons, great technical skill with conventional ultrasound is necessary to acquire high quality spinal images, interpret key spinal landmarks, and make accurate measurements.
Accuro addresses this challenge with two key new ultrasound imaging technologies. We have developed a new way of reconstructing images of bone structures called BoneEnhance®, which is analogous to Power Doppler but highlights bone surfaces rather than blood signal. Additionally, the Accuro uses an automated 3D spinal navigation technology, called SpineNav3D™, which provides real-time automated detection and depth measurements to key spinal landmarks, such as the spinous process and epidural space. Lastly, the Accuro is handheld and battery operated, weighing less than one pound, which makes it ideal for use on a busy L&D floor. In our experience, the combination of these technologies in Accuro allows most anesthesia providers to start gaining benefits of ultrasound guidance rapidly, usually within the first several procedures.
Medgadget: Are there interesting or relevant case examples of the Accuro that you can discuss?
Mauldin: At the University of Cincinnati, Beth Ann Clayton, DNP, MS, CRNA, Assistant Professor of Clinical Nursing provided a case study for us where Accuro was able to successfully guide the placement of a working CSE in five minutes in a morbidly obese patient. Prior to that, epidurals placed by two other anesthesia providers had failed within six hours of insertion. She noted: “Both the surgeon and patient were pleased with the Accuro results. It was a fabulous example of the need for this type of device.”
In another difficult case, shared at last year’s Society for Obstetric Anesthesia and Perinatology (SOAP) annual meeting, anesthesiologists at Rutgers-New Jersey Medical School noted that under Accuro guidance an epidural was successfully delivered to a pregnant patient with severe scoliosis and significant scarring and anatomical distortion due to treatment for the condition. They commented that Accuro successfully identified bony landmarks and the optimal location for anesthesia delivery, noting that the procedure was successfully performed with first-time needle placement. Conventionally delivered spinal anesthesia for scoliosis patients typically involves multiple needle insertions and extended procedure time.
Also shared at last year’s SOAP annual meeting, at University of Virginia Medical Center, an NIH-funded randomized controlled trial compared anesthesiology residents’ success placing spinal anesthesia in C-section patients with Accuro guidance and using conventional methods. The trial found that for residents with prior spinal anesthesia experience, Accuro more than doubled the first-attempt needle placement among other benefits.
In a second clinical trial conducted at Stanford University Medical Center, and published recently in Anesthesia & Analgesia, automated Accuro guidance successfully identified the location and depth for optimal epidural anesthesia administration with essentially equivalent accuracy to traditional ultrasound images read by an experienced interpreter.
Medgadget: The Accuro was cleared by the FDA in 2015. What has the adoption of the technology been like? Where is it used and how many have you shipped?
Mauldin: Adoption of Accuro has been strong with numerous satisfied users highly recommending the product. To date, several hundred units have been shipped worldwide, including to more than 50 university hospitals. With good feedback and excellent trial results in place, our next step is to expand our global distribution network to accelerate these adoptions.
The device is also used in ongoing or recently completed registered clinical trials at University of Virginia Health System, Charlottesville; The University of Texas Medical Branch, Galveston; Novant Health Forsyth Medical Center, Winston-Salem; and Lucille Packard Children’s Hospital, Palo Alto. Internationally, trials are being conducted at Istituto Ortopedico Rizzoli, Bologna, Italy, and Citta di Roma Hospital, Rome, Italy. Results have been excellent to date.
Medgadget: Do you see more potential for ultrasound systems coming out that are designed for specific use cases, as compared to general purpose devices?
Mauldin: Absolutely. Ultrasound is cost-effective to design and manufacture compared to most other imaging modalities. Compact size makes it extremely portable, easy to manipulate and therefore well-suited to use for a variety of specialized procedures. The challenge remains overcoming the steep learning curve when used beyond radiology. However, as the sophistication and precision of image guidance technology grows, ultrasound can expand to almost an unlimited number of use cases. Image guidance calls for pattern recognition and automated detection of anatomical landmarks that can be used to guide users to a specific location and to help unfamiliar users to interpret the images acquired. Technology vendors will need to focus on this functionality, along with methods of optimizing ultrasound images for bony anatomy, if and when this is involved.
Link: Rivanna Medical…
Medgadget flashback: Accuro Handheld Ultrasound Needle Guidance System Cleared by FDA…