A Medical Device Daily
Between FDA and the Centers for Medicare & Medicaid Services (CMS), the latter may have a stronger reputation for publishing a raft of guidances and memos, but FDA closed the gap last week with the publication of two drafts and two final guidances. One of the final guidances dealt with 510(k) applications (class II special controls) for tissue adhesives for topical approximation of skin, which was published in draft form in July 2007.
The guidance notes that the General and Plastic Surgery Devices advisory committee recommended the reclassification of cyanoacrylate tissues adhesives from class III (requiring a PMA) to class II with special controls in 2006. The committee also recommended the publication of a guidance, which deals strictly with a device "intended for topical closure of surgical incisions, including laparoscopic incisions, and simple traumatic lacerations that have easily approximated edges."
As is usually the case with such guidances, FDA recommends that a manufacturer stick with known test methods, but if the company opts to tweak an existing performance test method, it should "provide sufficient information to explain the nature of and the reason for the modification."
Sponsors should pay close attention to several risks associated with such devices, including unintentional bonding or leaking into the patient's eyes. However, wound dehiscence (separation of tissues) also is a concern, as is adverse tissue reaction.
FDA recommends that adhesive strength be gauged by using any one of four methods promulgated by ASTM (formerly the American Society for Testing and Materials; West Conshohocken, Pennsylvania), a list that includes ASTM F2255-05, a test for lap-shear. As for degradation of the device, the agency suggests that sponsors examine the decomposition of cyanoacrylate into formaldehyde because of potential histotoxicity. Sponsors should consider measuring degradation products and the presence of formulation additives and monomer impurities.
As for biocompatibility, the guidance suggests the use of ISO-10993 to evaluate contact with "breached or compromised surface with blood contact."
Animal studies in support of a filing should check for histopathology leading to delayed healing, and the agency states that it favors porcine animal models. Animal studies may eliminate the need for human clinical studies, but the agency notes that human studies may be needed if the device's "material formulations [are] dissimilar from designs or materials" used in the predicate. Also, any new technologies or indications may require human studies.
FFDM display guidance also finalized
Full-field digital mammography (FFDM) has changed the science of mammography, but not the problem of interpreting different image sources. However, FDA's May 30 guidance on displays and accessories for FFDM systems gives manufacturers some guidance on any 510(k) applications for those display systems.
Any application for a soft-copy display, such as a computer monitor, should include data on "the speed and bit-depth precision of digital-to-analogue converters," the guidance states, along with pixel (picture-element) parameters such as array dimensions, size and pitch.
An application for a hardcopy display system must also include data on pixel size and the minimum size of the recording pixel matrix. Spatial resolution is another parameter of interest for hardcopy.
Image archiving systems also are addressed in the guidance, which calls for data on any image data compression software that an archiving system might employ along with "data handling, storage and security features."
Heavily processed images are the order of the day, and the guidance recommends that a manufacturer include a description of how any such software functions as well as a detailed flowchart of the software's function. Manufacturers are also urged to provide a list of workstations known to be compatible with the program.
As for physical laboratory testing of softcopy systems, FDA recommends that sponsors provide data on luminance response and luminance uniformity as well as any geometric distortion known to be generated by the software. Manufacturers also will want to provide data on "chromacity ... measured at the center of the screen at 5%, 50% and 95% of the maximum luminance."
FDA also published draft guidances for class II special controls for angioplasty catheters and for FFDM mammography systems, which will be reviewed in an upcoming issue of Medical Device Daily.
Medicare NPI number now mandatory
CMS gave all providers and suppliers of medical equipment a reminder that they will all have to use their national provider identifier (NPI) numbers in any transactions that are subject to the rules of the Health Insurance Portability and Accountability Act (HIPAA).
The May 23 notice barely qualified as timely, given that the rule went into effect that same day.
On the other hand, acting administrator Kerry Weems said this should not be news to the affected parties. "We have been working with healthcare providers and their trade and professional organizations for more than two years to get us to this point of one unique number for identification," Weems said, warning providers that any transactions "that are sent with a legacy number will be rejected on and after the May 23 deadline."