Diagnostic neurosurgical microscope filter.

(a) Identification. A diagnostic neurosurgical microscope filter is a device intended for use during neurosurgery to visualize fluorescence and enhance visualization of tissue associated with a specific disease or condition. (b) Classification. Class II (special controls). The special controls for this device are: (1) Non-clinical performance testing must demonstrate that the device performs as intended under anticipated conditions of use, and verify and validate filter specifications and functional characteristics, including the following: (i) Spectrum and intensity of the illumination source; (ii) Spectrum of the excitation and emission filter modules when integrated in the surgical operating microscope; (iii) Excitation power and power density; (iv) Optical path loss from illumination source to objective lens or microscope camera; (v) Homogeneity of the excitation light at the focal plane; (vi) Fluorescence detection sensitivity; (vii) Verification of calibration or preoperative procedures; and (viii) If camera-based, spectral sensitivity of the camera. (2) Labeling must include: (i) Identification of the filter characteristics in conjunction with a compatible surgical operating microscope, to include the following: (A) Illumination spectrum and power density; and (B) Excitation and emission filter spectra. (ii) Instructions for calibration or preoperative checks to ensure device functionality prior to each use; (iii) Instructions for use with compatible surgical operating microscopes, external light sources, and cameras; (iv) A warning that the device should only be used with fluorophores approved for use within the specified spectral ranges; and (v) A warning that the device is not a standalone diagnostic. [86 FR 73973, Dec. 29, 2021]