The digital surgical microscope accessory GLOW400 is using the optical excitation and emission filtering of the FL400. The FL400 provides an illumination filter (380nm - 430nm) which when engaged into the light source path of the surgical operating microscope provides, via a light guide, a fluorescence excitation light system used in conjunction with an approved tumor-selective substance (fluorophore) (e.g. Protoporphyrin IX (PpIX) which is resulting of the metabolization of 5-ALA (5 - aminolaevulinic acid)) for tissue characterization in the open neurosurgery field. PpIX is strongly fluorescent with a peak at λ=635 nm as red-violet after excitation with blue light (λ=380-410 nm). The digital surgical microscope accessory GLOW400 is using the optical excitation and emission filtering of the FL400. The fluorescence signal visualized depicts the distribution of the dye in the patient's tissues during the surgical procedure.

Performance will be evaluated using Questionnaire, a structured Likert-scale survey completed by the operating surgeon during and after surgery.

The questionnaire assesses:

1. perceived intensity of fluorescence
2. perceived volume/ shape and relative location
3. perceived distribution of fluorescence
4. anatomical and fluorescence observation (GLOW400 Anatomy only)

Each item is rated on a 5-point Likert scale:

1. = Not available
2. = Insufficient
3. = Sufficient
4. = Very good
5. = Excellent

Higher scores indicate better performance.

The outcome is considered acceptable if all ratings are ≥3 (Sufficient or better).

Performance will be evaluated using Questionnaire, a structured Likert-scale survey completed by the operating surgeon during and after surgery. The questionnaire assesses::

1. Stereoscopic Perception (3D Depth perception)
2. Resolution
3. Noise
4. Latency

Each item is rated on a 5-point Likert scale:

1. = Not available
2. = Insufficient
3. = Sufficient
4. = Very good
5. = Excellent

Higher scores indicate better performance.

The outcome is considered acceptable if all ratings are ≥3 (Sufficient or better).

Performance will be evaluated using Questionnaire, a structured Likert-scale survey completed by the operating surgeon during and after surgery. The questionnaire assesses:

1. Neuroanatomy structures
2. Vascular structures 4. Perceived contrast (GLOW400 HiFluo only) 5. Bleeding visibility (GLOW400 Anatomy only) 6. Traces of remaining fluorescence (GLOW400 HiFluo only)

Each item is rated on a 5-point Likert scale:

1. = Not available
2. = Insufficient
3. = Sufficient
4. = Very good
5. = Excellent

Higher scores indicate better performance.

The outcome is considered acceptable if all ratings are ≥3 (Sufficient or better).

Safety will be evaluated using Questionnaire B, completed postoperatively by the surgical team. It captures:

1. Dizziness through using digital 3D visualization

2. Delayed, interrupted or hindered surgery due to different causes

3. Occurred injuries to the patient

4. Breach of sterility

5. Any patient or user tissue burn event reported.

6. Confirm user experience with the use of the device in real clinical practice, supporting the marketing claims:

   1. Confidence in decision
   2. Focus during procedure
   3. Surgical course of action
   4. User experience
   5. Mental fatigue

Responses are binary:

1. = Yes (event occurred)
2. = No (event did not occur)

Lower scores (2 = No) indicate better safety outcomes.

The outcome is acceptable if no safety events are reported.

The extent of tumor resection will be evaluated using volumetric analysis. The volumetric measurement will be carried out by a neuroradiologist. Precise three-dimensional (3D) rendering and analysis of pre-operative and post-operative MRI images, facilitating accurate assessment of residual tumor volume.

Radiology reports include:

• Residual tumor percentage %.

Based on the residual tumor percentage, the appropriate category will be selected (4):

• Complete tumor resection: (100% + 0 cm3 CE)
• Near total resection: (≥ 95% + ≤ 1 cm3 CE)
• Subtotal resection: (≥ 80% + ≤ 5 cm3 CE)
• Partial resection: (< 80% ± >5 cm3 CE)