Augmented reality and virtual reality (AR/VR) might never dominate the world of medical technology the way cardiology devices once had, but AR/VR products are becoming more important as digital health and telehealth play an increasingly central role in 21st Century healthcare. Many developers in the digital health space may wonder what they must do to meet the FDA’s expectations of these products, a subject we will examine in this blog.
In our previous blog, we reviewed some of the impediments to the development of an AR/VR product, the majority of which are regulated through the FDA’s 510(k) program. There are numerous FDA-recognized international performance standards for many of these device categories, but several of these product types require at least a basic clinical study, and occasionally a clinical trial with a control population of one type or another. While the prospects for AR/VR in the field of digital mental health are robust, we will take a moment to highlight the role this technology will play in the world of orthopedic surgery, a category that will experience a massive increase in volumes in the decades ahead.
Fourteen of the AR/VR systems cleared by the FDA for orthopedic use fall under the OLO product code for stereotactic surgical instrumentation. The applicable regulation for OLO devices is part 882.4560, which offers little insight into the FDA’s expectations. This part of the regulation is described as a stereotaxic instrument, which consists of a rigid frame with a calibrated guide mechanism that provides positioning probes or other devices/instruments within a patient's brain, spinal cord, or another part of the nervous system. The mention of the nervous system should not lead to the conclusion that this regulation includes all devices with a neurological indication, as some neurological stereotaxic instruments are covered by code HAW.
Latest Version of ASTM Standard Awaits FDA Recognition
The primary consensus standard of interest for this code is ASTM F2554-18, which the FDA has recognized, although ASTM updated this standard likely last year. It does not appear that the FDA has recognized the 2022 version of F2554, although the agency will formally recognize the updated version. A developer of an AR/VR system can use F2554 in bench testing to measure the positional accuracy of the surgical instruments used in a product that is cleared under OLO. With bench testing, the developer can document:
- The system’s precision in locating a point relative to a coordinate system;
- Relative point-to-point linear accuracy;
- The repeatability of coordinates of a single point; and
- The range of visible orientations of the reference frame and/or tools in an optically-based system.
Beyond bench testing, a cadaver study may be required to provide the FDA with data that is robust enough to confirm the accuracy of an AR/VR system under the OLO code. However, this is an emerging technology for some uses, such as total knee arthroplasty (TKA), and consequently, the premarket requirements for this application may be considerable.
One example of this is a study and a literature review for the use of AR/VR in TKA for the Knee+ system by Pixee Medical. This study included an assessment of surgeon motion sickness with the Virtual Reality Sickness Questionnaire (VRSQ), which helps to fulfill the FDA’s questions about cybersickness. The Knee+ system superimposes a view of the tibial and femoral axes through a pair of smart glasses and guides placed to provide bone landmarks, a key feature of this type of product that can induce disorientation.
This study enrolled only five patients, and while the authors said the results were sufficient to justify enrollment in a larger trial, this study and previous experience suggested that proper alignment of the cutting tools was more difficult along the sagittal axis than the coronal axis. The VRSQ scores were associated with a lack of vertigo or nausea the surgeon reported, ranging from 12.5 (on a scale of 0-33) on the first procedure to 4.17 on the fifth and final procedure.
This is just one of many metrics that highlight the essential role of surgeon training and experience in maximizing outcomes and minimizing repeat procedures. The results of this study should be helpful to developers interested in developing a system that addresses TKA, the demand for which is expected to more than triple between 2020 and 2040.
De Novo Required for AR/VR Indicated for Amblyopia
Luminopia Inc. obtained a de novo for one of the AR/VR products on the FDA list, the Luminopia One for the treatment of amblyopia in patients 4-7 years old. This device, which uses a VR headset to project images of cartoons into the user’s eyes, required a clinical trial with an enrollment of 117 subjects, with the subjects in the control arm required only to wear corrective eyewear during routine daily activity for 12 weeks.
Study subjects who used the Luminopia One were required to undergo one-hour sessions for six days per week for 12 weeks, and the clinical trial was reported in a major journal. Unfortunately, the attendant regulation (Part 886.5500) does not yet appear in Part 886., which will describe the requirements for the new product code of QQU.
The decision summary lends some detail as to how to fulfill the premarket requirements for a QQU product, such as IEC 60601-1 for the prevention of thermal injury. IEC 63145-20-10 can be used to ensure the image displayed inside the headset provides sufficient luminosity and contrast, but clinical performance testing will be required to demonstrate device performance. Non-clinical testing is recommended for parameters such as:
- Display resolution;
- Field of view;
- Image quality;
- Appropriate optical image distance; and
- Interpupillary distance.
We at Enzyme do not typically comment on coverage and reimbursement, but this is a critical consideration for the newest of these AR/VR technologies, particularly when there is no Medicare benefit category. Technology that falls into an existing benefit category might call for additional payment beyond the standard of care, which for devices indicated for hospital in-patient use is provided by the Medicare new technology add-on payment framework.
This part of a device’s path to market can become more complicated when the device is sufficiently novel to lack a code under the Current Procedural Terminology (CPT) coding system. In this scenario, the developer must petition for a new code, a process that takes longer than many in the digital device world might realize. In a recent example, two new category III CPT codes were issued for VR services, but obtaining these codes takes time, so we urge our clients to recognize that the FDA is only one of several hurdles that stand between them and a successful market launch.