Hi, I have no experience with accesories, but the scope of 21 CFR 820 does not seem to make any exclusions to accessories:
The scope of 21 CFR 820:
"(a)Applicability. (1) Current good manufacturing practice (CGMP) requirements are set forth in this quality system regulation. The requirements in this part govern the methods used in, and the facilities and controls used for, the design, manufacture, packaging, labeling, storage, installation, and servicing of all finished devices intended for human use."
Where
"Finished device means any device or accessory to any device that is suitable for use or capable of functioning, whether or not it is packaged, labeled, or sterilized." (definition l 820.3)
I do know in Europe, the Medical Device Derective applies as well to accessories:
Article 1."This Directive shall apply to medical devices and their accessories. For the purposes of this Directive, accessories shall be treated as medical devices in their own right. Both medical devices and accessories shall hereinafter be termed devices"
Hope it helps.