by Teri Cygnarowicz
My peers often ask, "What's an audiologist doing at the FDA?" The short answer is that many of the devices we use in everyday clinical practice must go through scientific and regulatory review at the U.S. Food and Drug Administration (FDA) before they are cleared for market. The long answer is contained in the remainder of the article.
Think about the devices in our clinical environments. Many audiologists are aware that hearing aids are medical devices regulated by FDA. Clinical audiometers, auditory brainstem response (ABR) equipment, otoacoustic emission (OAE) equipment, impedance audiometers, tinnitus maskers, cochlear implants, and implantable middle ear hearing devices are all under FDA purview. Battery powered artificial larynx, otoscopes, tympanostomy tubes, vocal fold medialization devices, endoscopes, and surgical drill systems are other products you might encounter.
Device Classification
In FDA's Center for Devices and Radiological Health (CDRH), Office of Device Evaluation (ODE) in the Ear, Nose and Throat Device Branch (ENTB), I am a scientific reviewer in the specialty of audiology and am responsible for reviewing and evaluating research protocols, and clinical and technical data.
To understand the FDA's scientific and regulatory review of medical devices, it's important to know about classifications for medical devices. Devices are classified into three categories according to risk and clinical experience:
- Class I devices. These devices usually carry the lowest health risk and are required to meet certain baseline regulatory controls, i.e., conformance with good manufacturing practices. Since 1997, most Class I devices are exempt from premarket review. This means that as a rule they do not require FDA premarket notification, or what is referred to as a 510(k), prior to being placed on the market.
- Class II devices. Most of these devices do require the premarket notification to be submitted and cleared by FDA prior to marketing. This documentation is needed in order to establish "substantial equivalence" (SE) to another device that is legally marketed in the United States. Class II devices are generally moderate risk and require "special controls" in addition to general controls. General controls include standards such as ANSI S3.22-2003, Specification for Hearing Aid Characteristics. Special Controls include items such as specific labeling requirements and postmarket surveillance, for example. For more information, visit the FDA Web site. Class II devices may also require clinical data to support an SE determination.
- Class III devices. These products carry the highest risk to patients. A premarket approval application, or PMA, must be submitted to the agency for review and evaluation of safety and effectiveness before marketing. The PMA is typically the culmination of a clinical trial for a device and usually is for those devices which carry the most risk to the patient.
Hearing Devices
Air conduction hearing aids are Class I exempt devices. The exemption means they do not require a 510(k) premarket notification and clearance by FDA prior to marketing. This exemption was granted to air conduction hearing aids and many other Class I medical devices with minimal risk of harm to the user. However, hearing aids are still regulated as restricted devices according to the federal hearing aid regulation (21 C.F.R. 801.420 and 801.421). It governs the patient and professional labeling of hearing aids, and their conditions for sale, including the medical evaluation and medical waiver. Bone conduction hearing aids are Class II devices and do require the submission, review, and clearance of a 510(k). They are also restricted devices and must comply with the hearing aid regulation. Audiometers (any type) and tinnitus maskers are all Class II devices.
Cochlear implants and implantable middle ear hearing devices are examples of Class III devices. Clinical data is required for Class III devices and the clinical trial is usually conducted under an investigational device exemption (IDE). The IDE permits a device to be shipped in interstate commerce for clinical investigation to gather data about its safety and effectiveness under conditions of its intended use.
It is important to note that final recommendations on pending applications are not completed by any one person. The review work of each application is done by a team of people. The Ear, Nose and Throat Devices Branch (ENTB) staff is composed of one registered nurse, two otolaryngologists, two audiologists, one toxicologist, and one electrical engineer. Other scientists are available to the Branch as consulting experts, including biomedical, electrical, software, mechanical and material engineers; neurophysiologists; biostatisticians; medical officers; and public health officials, including medical device law experts.
In order to accomplish its mission concerning medical devices, FDA also needs assistance from 18 Advisory Panels. Panel members are independent, scientific experts from various disciplines and serve a four-year term as voting members and may be retained as consulting members without a term limit. Industry and consumer representatives also serve on the panels. The ENT Devices Panel consists of otolaryngologists, audiologists, hearing scientists, biomedical engineers, electrophysiologists, biostatisticians, and others, as needed.
Premarket Approval
So what could possibly be contained in these voluminous documents, you might ask? There is a fair amount of administrative and legal documentation contained in premarket submissions. However, in the case of a PMA, pretty much everything that went into developing the product goes into the submission. This includes all pertinent preclinical information, including bench and animal testing. Clinical data and statistical data analysis, including the Case Report Form (CRF) are also provided in the submission. The device and all accessories are described and engineering drawings are provided in the PMA submissions. Design validation and verification testing protocols and results are submitted in the PMA.
All labeling and promotional material (even if it is only draft) are included, such as the physician package insert, surgical manual, audiology manual, user manual, and any other written information regarding the device. A "Summary of Safety and Effectiveness" is also required, which summarizes all information pertaining to the safety and effectiveness of the device. This important document is a statutory requirement of the PMA and becomes publicly available upon device approval (see resources online).
We at CDRH strive to work in partnership with the medical device industry in order to ensure that safe and effective medical devices are available and expedited to both patients and medical professionals. I feel that I am contributing to the public health in a unique way. I have achieved my dream job.
Teri Cygnarowicz is a scientific reviewer/audiologist with the Ear, Nose and Throat Devices Branch, Office of Device Evaluation, Center for Devices and Radiological Health at the Food and Drug Administration in Rockville, MD.