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The g.Estim PRO is intended for functional brain mapping via electrical stimulation prior to cortical resections in the vicinity of essential cortex. The device must be used by trained and qualified personnel within a medical environment.

Device Description

The g.Estim PRO is a neural, constant current, monophasic stimulator for electrical stimulation of the brain (cortical stimulator). The device is battery supplied and can be controlled via USB from a computer. It can be trigged via software or with external devices and can provide beside the stimulation pulse also trigger signals for other devices. The system consists of the stimulator, a USB connector cable to connect the device to a host computer, trigger out cables and trigger in cables, the driver and software package (including a graphical user interface and communication interface). Additionally the device can be triggered with a hand switch and/or foot switch. The stimulator can be programmed and is a constant-current stimulator that can deliver electrical pulses with alternating polarities, lengths, amplitudes or trains of such pulses. The device is connected via USB to a computer and on the computer stimulator settings can be performed. On the computer a graphical user interface allows to perform all settings required for the stimulator. The stimulator is battery powered and has an optical isolation from the computer for safety reasons. A LED shows the stimulus time point. The stimulator allows to send trigger pulses to external devices to synchronize the stimulus e.g. with EEG data acquisition devices. Such a trigger pulse can be programmed to occur prior to the stimulus so that e.g. a switching unit can switch before the stimulus occurs and can last longer than the electrical pulse to switch back after the pulse. Furthermore the triggers can be perfectly aligned with the stimulus so that an accurate trigger signal can be sent to the external device. The trigger lines are TTL compatible. Two trigger lines are supported. The stimulus can be triggered via the software running on the computer or via external inputs to the stimulator. Important is that the stimulus is triggered very accurately for perfect synchronization. A foot switch or hand switch can be used to trigger the stimulator. The trigger input is TTL compatible. One trigger line is supported. The device can perform an impedance measurement to check the electrodes impedance before the stimulation is done and can measure the actual stimulation current when a stimulation is done. The results are shown in the graphical user interface and can be passed also to other applications via an interface. The impedance measurement is done quickly so that the stimulation can rapidly be performed. If a high impedance is detected the stimulator does not stimulate. g. Estim PRO works in the same manner as the approved and predicate device.

AI/ML Overview

Based on the provided text for the g.Estim PRO, here's a description of the acceptance criteria and the study proving the device meets them:

Disclaimer: This device, "g.Estim PRO," is a cortical stimulator, not an AI-powered diagnostic device. Therefore, many of the typical acceptance criteria and study aspects related to AI (e.g., ground truth establishment for AI, MRMC studies, training/test sets for AI, effect size of human reader improvement with AI) are not applicable to this submission. The provided text describes a traditional medical device submission focused on demonstrating substantial equivalence to a predicate device primarily through technical specifications, safety, and functionality.

Acceptance Criteria and Device Performance for g.Estim PRO

This submission demonstrates substantial equivalence to a predicate device (Chatten Associates S12X, K082629). The "acceptance criteria" for this type of submission are implicitly tied to demonstrating that the new device is as safe and effective as the predicate, despite minor differences. The performance is assessed by comparing technical specifications and functionalities.

1. Table of Acceptance Criteria and Reported Device Performance

The provided 510(k) Summary includes a comparative table (Section 807.92(a)(6)) that serves as the basis for demonstrating substantial equivalence. The "acceptance criteria" are the features and performance parameters of the predicate device, and the "reported device performance" are the corresponding features and parameters of the g.Estim PRO.

Item	Implied Acceptance Criteria (Predicate: Chatten Associates S12X)	Reported Device Performance (g.tec medical engineering GmbH: g.Estim PRO)	Comments (Rationale for Equivalence)
1. Intended Use	For intraoperative cortical stimulation mapping to aid in cortical resections in the vicinity of essential cortex.	For functional brain mapping via electrical stimulation prior to cortical resections in the vicinity of essential cortex.	Reduced intended use (no switching unit) but equivalent in safety and effectiveness.
2. User	Medically trained and qualified personnel in medical environment.	Medically trained and qualified personnel in medical environment.	Same as predicate.
3. Current Type	Constant current bi-phasic, rectangular.	Constant current, bi-phasic, rectangular.	Same as predicate.
4. Maximum Stimulation Charge	20 μC	15 μC	Lower limit for additional safety, but equivalent in effectiveness.
5. Pulse Polarity	Selectable (positive, negative, alternating).	Selectable (positive, negative, alternating).	Same as predicate.
6. Train Duration	0.2 to 20 sec in 7 steps.	0.1 to 20 sec.	Shorter minimum train duration but equivalent in safety and effectiveness.
7. Pulse Amplitude	0.2 - 15 mA (peak), constant current, 17 steps.	0.05 - 15 mA (peak), constant current, 0.01 mA increments.	Allows lower start value, lower increments, but equivalent in safety and effectiveness.
8. Stimulation Frequency	2 - 100 Hz in 7 steps.	2-100 Hz, 0.1 Hz steps.	Same frequency range and smaller increments for more flexibility, but equivalent in safety and effectiveness.
9. Stimulation Pulse Duration	0.1 - 1.0 ms per phase (15 mA max); up to 2 ms per phase (10 mA max).	0.1 ms - 1 ms per phase.	1 ms is long enough to achieve necessary stimulation, but equivalent in safety and effectiveness.
10. Max. Transient Voltage	34V, Zener Diode for hardware safety.	80V, lead off via software for safety.	Higher voltage for smaller electrode sizes but equivalent in safety and effectiveness.
11. Power Supply	12V DC, External medical power supply.	Battery, 2 x 9 V.	Battery supply to reduce risk and noise.
12. Electrode Size	Warning that electrodes with less than 4 sq mm can cause tissue damage.	Electrode size defines the safety threshold for stimulation parameters; device calculates max. stimulation current depending on electrode size.	Safe also with smaller electrode size due to calculation, equivalent in safety and effectiveness.
13. Supported Electrodes	Strip, grids, handheld probe.	Strip, grids, handheld probe.	Same as predicate.
14. Stimulus Switching Unit	Yes.	No.	Just a cortical stimulator for 1 bipolar channel, but equivalent in safety and effectiveness.
15. Use Standard Sensors and Electrodes	Electrodes are not included.	Electrodes are not included.	Same as predicate.
16. User Input	Stylus (touch), standard mouse.	Standard computer.	Standard computer, but equivalent in safety and effectiveness.
17. Graphical User Interface	LCD.	LCD display of computer.	Same as predicate.
18. Simulator Parameters Setting	Through displayed controls.	Through displayed controls.	Same as predicate.
19. Active Stimulation LED	Yes.	Yes.	Same as predicate.
20. Actual Current Delivered Displayed	Yes.	Yes.	Same as predicate.
21. Dimension	337 x 165 x 178 mm.	240 x 137 x 80 mm.	Smaller and easier to handle, but equivalent in safety and effectiveness.
22. Weight	2.25 kg.	0.85 kg.	Lighter and easier to carry, but equivalent in safety and effectiveness.
23. Trigger out for external devices	Yes.	Yes.	Same as predicate.
24. Digital Input	Isolated.	Isolated.	Same as predicate.
25. Patient Isolation	BF.	BF.	Same as predicate.
26. Safety Standards	IEC60601-1, IEC60601-1-2.	IEC60601-1, IEC60601-1-2, IEC60601-2-40, ISO14971, IEC62304, IEC62366.	More standards applied.
27. System Components	Stimulator, Switching array, Hand controller, Touchscreen Stylus, Power Supply, Portable carry case, Cables.	Stimulator with USB cable, Hand switch and foot switch, Portable carry case, Trigger in/out cables.	g.Estim PRO does not provide a switching array, Touchscreen Stylus and power supply, but adds foot switch and trigger cables. Equivalent in safety and effectiveness.
28. Firmware / Software	Resident firmware.	Resident firmware inside g.Estim PRO, API/GUI on computer.	Additional Front-end driver to operate but equivalent in safety and effectiveness.
29. Log file	YES on device transferred with USB flash stick.	YES on computer.	Not saved on device, but equivalent in safety and effectiveness.
30. Digital inputs/outputs	1 external trigger input (disabled), 1 train duration out, 1 trigger out (pulse).	1 trigger input (disabled), 1 pulse output, 1 pulse output to trigger external devices.	Programmable outputs but equivalent in safety and effectiveness.
31. Connectors, switches	Various (handheld controller/probe, output to switching unit, USB, Ethernet, HW switches).	Hand/foot switch connector, safety sockets, USB, DIO in/out, battery housings, on/off switch.	Different connectivity (e.g., no switching unit output, no Ethernet, no HW-switches), but equivalent in safety and effectiveness.
32. Impedance Measurement	Yes.	Yes.	Same as predicate.
33. Isolated Power Out	Yes.	No.	No isolated power out but equal in safety and effectiveness.
34. Embedded Controller	1.	2.	One additional to ensure equal safety and effectiveness.

2. Sample size used for the test set and the data provenance

For this traditional medical device submission, there isn't an "AI test set" in the sense of a dataset of patient images or physiological signals. The "test set" consists of the physical device and its components, which were subjected to various engineering tests to verify their functionality and safety according to defined specifications and standards.

Sample Size: The sample size for testing would typically be a specific number of manufactured units of the g.Estim PRO device. The text does not specify the exact number of units tested, but it is implied that a sufficient number were tested to demonstrate reliable performance.
Data Provenance: The tests are performed in a laboratory/engineering environment. The "data" provenance refers to the results of these technical and safety tests. The device manufacturer, g.tec medical engineering GmbH, is based in Austria (Europe). The tests would have been conducted by the manufacturer or accredited testing facilities. The data is prospective, generated specifically for this submission.

3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts

This is not applicable as the submission is for a medical device (cortical stimulator), not an AI diagnostic tool requiring ground truth established by medical experts on patient data. The "ground truth" for this type of device is its adherence to engineering specifications, safety standards, and functional requirements, which are verified through technical measurements and testing. This is typically done by qualified engineers and technicians.

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

Not applicable for a non-AI medical device testing, as there are no interpretations of medical images/data that require adjudication. Functional and safety tests have pass/fail criteria.

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

Not applicable. This is not an AI-powered device, and it does not involve human readers interpreting medical cases.

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

Not applicable. This is a medical device, not an algorithm. Its performance is inherent to its physical and software functionality. The text states:

"The stimulator was tested with a data acquisition device and provides rectangular stimulation pulses with the necessary frequency and amplitude range."
"Furthermore digital outputs were tested to provide trigger signals and digital inputs were tested to trigger the stimulation."
"The impedance measurement was tested with test impedances."

These describe standalone functional tests of the device's hardware and integrated software.

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

The "ground truth" for this device is primarily the predefined engineering specifications, functional requirements, and relevant safety standards (e.g., IEC 60601-1, IEC 60601-1-2, IEC 60601-2-40, ISO 14971, IEC 62304, IEC 62366). The device's performance is verified against these objective, measurable criteria.

8. The sample size for the training set

Not applicable. This is not an AI device trained on a dataset.

9. How the ground truth for the training set was established

Not applicable. There is no AI training set for this device.

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