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The Leica FL400 is a surgical microscope accessory filter set for viewing fluorescence of fluorophores comprising an excitation filter for blue spectral range 380 mm - 430 nm and an observation filter comprising the long-wave blue, green, yellow and red spectrum in the spectral band greater than 444 nm.

The FL400 is a surgical microscope accessory used in fluorescent visualization of suspected grade III or IV gliomas during neurosurgery.

The Leica FL400 is a fluorescence accessory that consists of an excitation (illumination) filter module and an emission (observation) filter module that are intended to be inserted into the optical beam path of compatible Leica surgical operating microscopes models M525 and M530. The excitation filter (380 nm - 430 nm), when placed into the light path, provides a fluorescence excitation light system for use in conjunction with an approved fluorophore selective for grade III or IV malignant gliomas.

The emission filter is a long pass filter allowing light wavelengths greater than 444 nm to pass. The fluorophore emits light at a longer wavelength than the excitation light. Once passed through the emission filter module, a camera adapted to the surgical microscope detects the fluorescence signal, allowing the user to visualize the fluorophore in the open neurosurgery field.

The Leica FL400 is supplied with a test phantom to confirm proper pre-operative fluorescence set-up. The Leica FL400 Test Phantom offers multiple levels of fluorescence intensity, which provides the clinician with a visual assessment of the FL400 pre-operative set-up. The clinician is advised to confirm the fluorescence spots are visible to confirm functionality prior to utilization.

Here's a breakdown of the acceptance criteria and the study that proves the Leica FL400 meets those criteria, based on the provided text:

Acceptance Criteria and Reported Device Performance

• Maximum Power and Irradiance of the Illumination Source: The maximum output power and irradiance were measured with a power meter at the end of the microscope light guide prior to application of the excitation filter module. |
  | (ii) Spectrum of the excitation and emission filter modules when integrated in the surgical operating microscope; | - Irradiance Spectrum of the Excitation Light and Spectral Response of the Excitation Filter: The irradiance spectrum (300 nm - 1100 nm) of the illumination light, following passage through the excitation filter module, was measured at working distances of 30 cm (M525) and 35 cm (M530) with a spectrometer. The spectral response of the excitation filter was derived by dividing this by the illumination source spectrum without the filter.
• Spectrum of the Emission Filter: The spectrum (300 nm – 1100 nm) of the emission filter when integrated in the surgical operating microscope was measured, including all coatings and optics. Transmission of the emission filter was calculated from white light remission spectra. |
  | (iii) Excitation power and power density; | - Maximum Excitation Power and Power Density: The maximum power (mW) and power density (mW/cm²) of the excitation light was measured with a thermopile and UV diode at multiple working distances and zoom settings. These measurements were compared to excitation power densities observed in clinical trials assessing fluorophore efficacy. |
  | (iv) Optical path loss from illumination source to objective lens or microscope camera; | - Optical Path Loss: Calculated by dividing the output signal measured at the microscope eyepiece (without emission filter) by the illumination signal measured at the microscope focal plane for the same zoom setting, using a reflection standard. |
  | (v) Homogeneity of the excitation light at the focal plane; | - Homogeneity of the Excitation Light at the Focal Point: The reflected signal from a white sheet of paper was imaged by the surgical operating microscope camera, and the intensity profile was calculated to demonstrate homogeneity. |
  | (vi) Fluorescence detection sensitivity; | - System Sensitivity: A diffusely reflecting and fluorescent silicone disc was positioned at 30 cm working distance. The device output spectrum was measured by a spectrometer at the microscope eyepiece for different zoom settings. The fluorescence/remission ratio was calculated. |
  | (vii) Verification of calibration or pre-operative procedures; | - Pre-Operative Phantom Test: This test demonstrated that the Leica FL400 test phantom is suitable for pre-operative checks. The phantom, with 4 dots of different fluorophore concentrations, was imaged by the camera and observed through eyepieces at different working distances and zoom settings. |
  | (viii) If camera-based, spectral sensitivity of the camera. | - Spectrum of Camera Filter: Measured to demonstrate that it can block near infrared and infrared leakage of excitation light to the camera. This implies the camera's filter sensitivity is appropriate for the system. |

Study Details

The provided document describes no clinical studies for the Leica FL400 itself. The special controls and the benefit-risk determination rely entirely on non-clinical/bench studies to demonstrate the device's technical performance and its compatibility with an existing, FDA-approved fluorophore (aminolevulinic acid hydrochloride - ALA HCl). The efficacy of ALA HCl was demonstrated in prior clinical studies for which the Leica FL400 effectively acts as a visualization system with compatible spectral characteristics.

Here's the information requested based on the provided text:

1. Sample size used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective):

   • Test Set Sample Size: Not applicable. No clinical test sets were used for the Leica FL400 device performance. The bench tests involved various optical measurements and simulated scenarios (e.g., test phantom, white reflection standard).
   • Data Provenance: Not applicable for clinical data. The non-clinical/bench testing was performed by the manufacturer, Leica Microsystems (Schweiz) AG. The source of the clinical data for ALA HCl is referenced as FDA's Center for Drug Evaluation and Research (CDER) under NDA 208630, which would generally be multi-national and prospective, but this pertains to the fluorophore, not the device's clinical performance.

2. Number of experts used to establish the ground truth for the test set and the qualifications of those experts (e.g. radiologist with 10 years of experience):

   • Not applicable. As no clinical studies were performed for the Leica FL400, no experts were needed to establish ground truth for a clinical test set. The technical specifications and measurements from bench testing serve as the "ground truth" for the device's optical performance.

3. Adjudication method (e.g. 2+1, 3+1, none) for the test set:

   • Not applicable. There was no clinical test set requiring expert adjudication.

4. If a multi reader multi case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance:

   • No. An MRMC comparative effectiveness study was not done. The Leica FL400 is a hardware accessory (filter set), not an AI-assisted diagnostic tool.

5. If a standalone (i.e. algorithm only without human-in-the loop performance) was done:

   • Not applicable. The Leica FL400 is not an algorithm. It's a filter set that requires a human neurosurgeon to interpret the visualized fluorescence through a microscope.

6. The type of ground truth used (expert consensus, pathology, outcomes data, etc):

   • For the Leica FL400, the "ground truth" for its performance is derived from physical measurements and engineering specifications obtained during bench testing. For example, measured spectra, power densities, and calculated optical path losses are compared to design specifications and relevant external data (e.g., fluorophore characteristics).
   • The clinical efficacy of the fluorophore (ALA HCl) that the FL400 is designed to visualize was established based on clinical studies with ground truth likely derived from histopathology (for positive predictive value) and potentially adjudicated clinical follow-up/outcomes (for negative predictive value limitations), as described in the summary stating "PPV ranged from 96% to 98%" and "NPV ranged from 19% to 24%." However, this is for the drug, not the device.

7. The sample size for the training set:

   • Not applicable. The Leica FL400 is a hardware device (filter set), not an AI algorithm. There is no training set in this context.

8. How the ground truth for the training set was established:

   • Not applicable. There is no training set.

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The GLOW800 is a Leica Surgical Microscope accessory used in viewing intra-operative blood flow and related tissue perfusion in the cerebral vascular region as well as blood flow following plastic and reconstructive surgery and coronary artery bypass grafting (CABG).

Similar to the predicate device (Leica FL800 most recently cleared under K141136 and previously in K061871 and K080612), the GLOW800 is an accessory to the Leica Microsystems (LMS) Class I 510(k) exempt surgical operating microscope (SOM).

The GLOW800, a non-contact, non-invasive device similar to its predicate, allows the surgical microscope to produce excitation light and resolve fluorescent emission from the fluorescent agent Indocyanine green (ICG). The generated fluorescence signal depicts the distribution of the infra-red dye in the patient's blood vessels during the surgical procedure (fluorescence video angiography). The ICG fluorescence peak is captured for display on the SOM screen. Using an additional camera to capture the visible light (VL) video stream and digitally combining with the Near Infra-red (NIR) video stream presents a high definition display of the surgical site as a pseudocoloured combined image of the same field of view (FOV), which includes anatomical information.

The GLOW800 utilizes the illumination light source, supplied as standard with the SOM to produce excitation light which is filtered using an illumination filter (also referred to as the excitation filter) within the 750 and 800 spectral wavelength range.

The provided text describes the regulatory clearance for the GLOW800 device, comparing it to a predicate device (Leica FL800 ULT). The crucial information regarding acceptance criteria and study results comes primarily from the "Substantial Equivalence Summary Table: Comparison to Predicate Device" and the "Non-Clinical, Bench, and Clinical Performance Testing" sections.

Here's an analysis of the acceptance criteria and the study that proves the device meets them, based on the provided text:

Key Takeaway: The GLOW800 device did not undergo a study with pre-defined quantitative acceptance criteria for its performance in the way one might expect for an AI/algorithm-driven device. Instead, the "acceptance criteria" were based on demonstrating functional equivalence to a predicate device through various non-clinical (bench) and preclinical (animal model) studies, and human factors testing. The primary "performance" metric was qualitative assessment (visualization ability) by experts.

1. Table of Acceptance Criteria and Reported Device Performance

2. Sample Sizes Used for the Test Set and Data Provenance

• Bench Testing: Described as "one-arm study using only the subject device GLOW800 on microscope platform M530 OH6 and assessed vs. historical experience with predicate FL800 (historical control)." No specific sample size for the "test set" in terms of number of devices tested is explicitly stated, but it implies a single GLOW800 unit was extensively tested against pre-established criteria and historical data.
• Preclinical Study:
  • Sample Size: 8 pigs.
  • Data Provenance: Conducted at the University of Mainz, Germany Institute of Neurosurgical Pathology. This was a direct comparative test, not a retrospective assessment.
• Human Factors Testing:
  • Sample Size: 21 surgeons and 15 nurses/other allied health professionals.
  • Data Provenance: Conducted at the Mt. Sinai Medical Center Neurosurgery Simulation Core, Annenberg Building, New York. This was a prospective study in a simulated operating room environment.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts

• Preclinical Study (Porcine Model):
  • Ground truth was based on "independent scoring assessments predefined within the protocol."
  • Experts involved in the assessment were "cardiovascular surgeon, neurosurgeons and veterinarians." The number of each type of expert is not specified, nor is their specific experience level (e.g., "10 years of experience").
  • The results state "n=18 comparative reviews," implying 18 assessments of the image sets. It's unclear if this means 18 different experts, or 18 reviews conducted by a smaller group of experts. Given the "independent scoring assessments" and the stated types of experts, it suggests multiple experts.
• Human Factors Testing: The "ground truth" for human factors was based on the ability of users (surgeons, nurses/techs) to perform tasks correctly and intuitively, assessed via "observational analysis." The primary "experts" here were the observers assessing performance against the predefined tasks and acceptance criteria, but their specific qualifications are not detailed beyond "observers."

4. Adjudication Method for the Test Set

• Preclinical Study: "Independent scoring assessments predefined within the protocol." This suggests that multiple experts made assessments, but the specific adjudication method (e.g., majority vote, consensus meeting, 2+1, 3+1) is not specified beyond being "independent."
• Human Factors Testing: "Observational analysis" with "pre-defined test cases and objective pass/fail criteria." No specific adjudication method among observers is mentioned, but the outcomes (e.g., "100% of users... perform key functions") suggest clear-cut observations rather than needing complex adjudication.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, If So, What Was the Effect Size of How Much Human Readers Improve with AI vs. Without AI Assistance

• No MRMC study was done in the context of AI assistance.
• The GLOW800 is a hardware accessory (optical system, camera, and basic software for combining images), not an AI/algorithm. Its purpose is to visualize blood flow, not to interpret or provide diagnostic insights based on that visualization. Therefore, the concept of "human readers improve with AI vs without AI assistance" does not apply to this device submission.
• The "comparative effectiveness" was primarily demonstrated by showing functional equivalence between the new device and a predicate optical device, meaning the new device provides similar or better visual information.

6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done

• This question is largely irrelevant as the GLOW800 is a hardware device (an accessory to a surgical microscope) designed for human use, not a standalone algorithm. Its "performance" is inherently tied to its ability to present visual information to a human operator.
• The "bench testing" does cover aspects of the device's technical performance (e.g., optical specifications, software functionality) in a "standalone" or de-coupled manner, ensuring it correctly processes and displays information.

7. The Type of Ground Truth Used

• Bench Testing: Internal design specifications, historical performance data of the predicate device, and "experiential basis" from prior device marketing history.
• Preclinical Study: The "actual" blood flow and vessel architecture in the porcine model (as visualized by the predicate device and assessed by expert observation of both devices' outputs) served as the de facto ground truth. The goal was functional equivalence in visualization, not an independent "pathology" ground truth of true blood flow given the real-time nature of the imaging.
• Human Factors Testing: Pre-defined "objective pass/fail criteria" for task performance and qualitative assessment of usability.

8. The Sample Size for the Training Set

No "training set" (in the context of machine learning) is mentioned or implied, as this device does not appear to employ machine learning or AI algorithms requiring a training phase.

9. How the Ground Truth for the Training Set Was Established

Not applicable, as there is no mention of a training set for an AI/ML algorithm.

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The Leica FL560 is a surgical microscope accessory used in viewing intra-operative blood flow in the cerebral vascular area.

Similar to the predicate device (Leica FL800 ULT approved under K141136), the Leica FL560 is an accessory to the Leica Microsystems (LMS) Class I 510(k) exempt surgical operating microscope (SOM). The Leica FL560 utilizes the illumination light source, supplied as standard with the SOM to produce excitation light which is filtered using an illumination filter (also referred to as the excitation filter) within the 460 - 500nm wavelength. An observation filter is introduced into the observer light path within the optics carrier of the SOM to enable visualization of the resulting fluorescence emission comprising of the green, yellow and red spectrum in a spectral band above ~510nm.

Here's a summary of the acceptance criteria and the study details for the Leica FL560, based on the provided text:

1. Table of Acceptance Criteria and Reported Device Performance

The document does not explicitly present acceptance criteria in a quantitative table format with specific thresholds. Instead, it describes acceptance as achieving "functional equivalence" to the predicate device (Leica FL800 ULT) in various aspects. The reported performance confirms this equivalence.

2. Sample Size Used for the Test Set and Data Provenance

• Bench Testing: The document states this was a "one-arm study using only the subject device FL560 on microscope platform M530 OH6". The sample size for filters is mentioned as being tested (optically, mechanically, geometrically assessed), but specific numbers are not provided. The data provenance is internal design verification testing ("in-house").
• Preclinical Testing:
  • Sample Size: "Six comparative image sets of the same cerebrovascular anatomy in either non-occluded (patent, native) or occluded (clipped) status and representative of neurosurgical procedures were visualized by both the FL560 and FL800ULT systems." This refers to the cases. The report also states "(n=18 comparative reviews, 100% confirmation)", which implies 3 observations per comparative image set (6 sets * 3 observations = 18 reviews).
  • Data Provenance: Prospective animal study conducted at the University of Mainz, Germany Institute of Neurosurgical Pathology, using a porcine model.
• Human Factors Testing:
  • Sample Size: "15 users per group were assessed via observational analysis." There were two distinct user groups (neurosurgeons, nurses/techs), so a total of 30 users.
  • Data Provenance: Prospective study conducted at the University of Utah Department of Neurosurgery, using a simulated operating room and a cerebral vascular aneurysm phantom model.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts

• Preclinical Testing: "Testing was completed at the University of Mainz, Germany Institute of Neurosurgical Pathology by neurosurgeons and veterinarians". The specific number of each is not given, but multiple experts from each specialization were involved. Their qualifications are stated as "neurosurgeons and veterinarians".
• Human Factors Testing: This study focused on usability and performance by the users themselves rather than establishing a diagnostic ground truth. The "experts" involved were the primary users: "neurosurgeons" and "nurses/techs". The number of each was 15. The study itself was designed in accordance with FDA guidance for human factors.

4. Adjudication Method for the Test Set

• Preclinical Testing: "independent scoring assessments that were predefined within the protocol." The specific adjudication method (e.g., 2+1, 3+1) is not detailed, but it implies multiple experts evaluating the images.
• Human Factors Testing: This study involved "observational analysis" with "objective pass/fail criteria pre-defined within the protocol." It doesn't describe a separate adjudication process for ground truth establishment, but rather for performance of tasks by the users.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance

The studies described are not MRMC comparative effectiveness studies comparing human readers with and without AI assistance. The Leica FL560 is a surgical microscope accessory for viewing fluorescence, not an AI-powered diagnostic tool. The preclinical study was a comparative functional equivalence study between two devices (FL560 vs. FL800ULT) for blood flow visualization, and the human factors study assessed usability.

6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) was done

This information is not applicable. The Leica FL560 is a hardware accessory for a surgical microscope. It does not contain an "algorithm" as typically referred to in AI/standalone performance studies. Its performance is entirely dependent on human-in-the-loop operation, as it provides visual information to the surgeon.

7. The Type of Ground Truth Used

• Preclinical Testing: The ground truth for evaluating blood flow visualization was established by the experts (neurosurgeons and veterinarians) observing the same cerebrovascular anatomy in known "non-occluded (patent, native) or occluded (clipped) status". This can be considered expert consensus with known physiological status/surgical intervention. The comparison was between the images produced by the two devices, FL560 vs FL800ULT, in relation to the actual blood flow patterns in the porcine model.
• Human Factors Testing: The "ground truth" here related to the correct and safe operation of the device and the visibility of fluorescein. This was established by "pre-defined test cases and objective pass/fail criteria" and successful visualization in a "cerebral vascular aneurysm phantom model". This is effectively known device functionality and phantom model characteristics.

8. The Sample Size for the Training Set

This information is not applicable. The Leica FL560 is a medical device accessory, not an AI model requiring a training set.

9. How the Ground Truth for the Training Set Was Established

This information is not applicable, as there is no AI model or training set involved.

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The Leica FL800 is a surgical microscope accessory used in viewing bypass grafts during coronary artery bypass (CABG) surgery, as well as blood flow during plastic and reconstructive surgery.

The Leica FL800 device is an accessory to the Leica surgical microscopes. It allows the surgical microscope to produce excitation light and resolve fluorescence light from the fluorescent agent ICG. The generated fluorescence signal depicts the distribution of the infrared doct in the patient's blood vessels during the operation (fluorescence video angiography).

The provided text does not contain information about acceptance criteria or a study that proves the device meets those criteria.

The document is a 510(k) summary for the Leica FL800, focusing on establishing substantial equivalence to existing devices for an extension of use into coronary vascular and bypass surgery, as well as plastic and reconstructive surgery. It clearly states:

"The Leica FL800 is an existing device which was granted market clearance by the FDA following the submission of a 510(k) pre-market notification (K061871). Leica Microsystems seeks only an extension of use into coronary vascular and bypass surgery, as well as plastic and reconstructive surgery. There will be no change to the device design, function or technical characteristics."

This means that the device's original performance and safety were established in a prior submission (K061871), and this current submission (K080612) is about expanding its indicated uses without altering the device itself. Therefore, a new study to prove specific performance metrics for this particular submission is not described because the device's fundamental performance is assumed to be established.

As a result, I cannot provide the requested information about acceptance criteria and a study proving they are met from the given text.

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