(176 days)
The Nexstim Navigated Brain Therapy (NBT®) System 2 is indicated for the treatment of Major Depressive Disorder in adult patients who have failed to achieve satisfactory improvement from prior antidepressant medication in the current episode.
The Nexstim Navigated Brain Therapy (NBT®) System is a non-invasive, repetitive transcranial magnetic stimulation (rTMS) system that delivers repetitive pulsed magnetic fields of sufficient magnitude to induce neural action potentials in the prefrontal cortex to treat the symptoms of major depressive disorder (MDD) without inducing seizure in patients who have failed one (1) antidepressant medication.
The Nexstim NBT System 2 is used for patient treatment by prescription only and must be operated by a trained medical professional. It can be used in both inpatient and outpatient settings including physician's offices and clinics, psychiatric hospitals, and general medical/surgical hospitals with psychiatric units.
The Nexstim NBT System 2 consists of a group of devices designed to localize the stimulation site in the brain and deliver rTMS stimulation using controlling and interpretive software. Operational control of the Nexstim NBT System 2 is provided by the software.
The Nexstim NBT System 2 combines magnetic resonance imaging-based (MRI-based), three dimensional (3D) localization of cortical motor areas of the brain with non-invasive TMS and simultaneous electromyography (EMG) measurement to locate areas of the brain that are capable of evoking muscle responses when stimulated, and to locate the target area for depression therapy.
The Nexstim NBT System 2 software is used to import a patient's MR image slices to generate an accurate 3D model of the patient's head which can be electronically peeled back to reveal the anatomical structures of the brain.
The provided text is a 510(k) Premarket Notification from the FDA for the Nexstim Navigated Brain Therapy (NBT) System 2. This document is primarily focused on demonstrating substantial equivalence to a previously cleared predicate device, rather than providing a detailed clinical study demonstrating the device's efficacy against specific, quantitative acceptance criteria in the manner one might see for a diagnostic AI.
The "acceptance criteria" discussed in this document are primarily related to technical specifications and regulatory compliance for a neurostimulation device, and the "study" proving it meets them refers to verification and validation activities against these technical standards, and a direct comparison to a predicate device.
Therefore, many of the requested sections (e.g., sample size for test set, number of experts for ground truth, MRMC study, training set details) are not applicable or not explicitly detailed within this type of regulatory submission because the approval is based on demonstrating equivalence in technical characteristics and safety/performance, not on a novel clinical efficacy trial with specific, quantitatively defined "acceptance criteria" for a diagnostic algorithm's performance on a test set.
However, I can extract and present the information that is available and relevant to your request based on the provided document.
Acceptance Criteria and Device Performance (Based on Technical Equivalence)
The acceptance criteria here are implicitly met by demonstrating that the proposed device (Nexstim NBT® System 2 (Proposed Device)) is substantially equivalent to the predicate device (Tonica Electronik A/S Mag Vita TMS Therapy System w/ Theta Burst Stimulation ([K173620](https://510k.innolitics.com/search/K173620))) and the previously cleared version of its own device (Nexstim Navigated Brain Therapy (NBT®) System 2 ([K171902](https://510k.innolitics.com/search/K171902))), particularly for the new Intermittent Theta Burst (iTBS) Protocol. The "performance" is demonstrated by showing that the key technical characteristics are the same or comparable, and that compliance with relevant standards has been achieved.
Note: The performance here is primarily about technical specifications rather than statistical performance metrics (like sensitivity, specificity, AUC) for a diagnostic output, as this is a therapeutic rather than a diagnostic device, and the submission is focused on substantial equivalence.
| Acceptance Criteria Category (Derived from Equivalence Argument) | Reported Device Performance (Nexstim NBT System 2 - Proposed Device) | Discussion/Proof of Meeting Criteria |
|---|---|---|
| Magnetic Field Intensity | 120% of MT | Same as predicate (K173620) and previously cleared device (K171902). |
| 10Hz Treatment Parameters (Frequency, Train Duration, Inter-train Interval, Number of Trains, Max Pulses/Session, Session Duration, Sessions/Week, Treatment Schedule) | Aligned with predicate characteristics and FDA-cleared minor protocol changes for other equivalent devices. | "The Nexstim NBT System 2 is technologically equivalent to the MagVita TMS Therapy System as demonstrated in 510(k) submission K171902/S001, pages 4818-4822." |
| iTBS Treatment Parameters (Magnetic Field Intensity, Frequency, Train Duration, Inter-train Interval, Burst Pulses, Number of Trains, Max Pulses/Session, Session Duration) | Aligned with K173620, ensuring consistent stimulus intensity within bursts. | "The iTBS protocol was cleared by FDA in the Mag Vita TMS Therapy System w/ Theta Burst Stimulation 510(k) submission K173620 for Tonica Electrnik A/S. The Nexstim NBT System 2 is technologically equivalent to the MagVita TMS Therapy System as demonstrated in 510(k) submission K171902/S001, pages 4818-4822." |
| Protocols | Standard 10 Hz and iTBS | Same as K173620 for both protocols. 10 Hz was already cleared in K171902. |
| Area of Brain to be Stimulated | DLPFC (Dorsolateral Prefrontal Cortex) | Same as predicate and previously cleared device. |
| Coil Material | Copper winding with air core | Same as predicate and previously cleared device. No change from coil cleared in K171902. |
| Coil Windings | 72 mm, 10 turns/wing | Same as predicate and previously cleared device. Same coil as cleared in K171902. |
| Amplitude Range | 0 to 2.5 SMT | Same as previously cleared device. No change from that cleared in K171902. |
| Pulse Length | 230 µs ± 5 µsec | Same as previously cleared device. No change from that cleared in K171902. |
| Frequency Range | 0.1 - 50 Hz (includes iTBS frequency of 50 Hz) | No change from range cleared in K171902. |
| Coil Positioning Principle | Individual patient direct targeting of anatomical treatment location (DLPFC) using 3D MRI model | Same as previously cleared device. No change from that cleared in K171902. Differs from predicate which uses indirect targeting. However, this is already an established feature of the Nexstim NBT System (cleared in K171902). |
| MT Response Detection | EMG provides qualitative and quantitative data based on which user defines MT. | Same as previously cleared device. No change from that cleared in K171902. (Predicate uses visual qualitative monitoring). |
| Sterilization & Shelf Life | Not shipped sterile. NBT Head Tracker: 2 years. Focal/Cooled Coils: 2M pulses or 2 years. | Verified through testing. |
| Biocompatibility | Complies with ISO 10993-1:2009. | Determined safe for patient contact. |
| Software Verification & Validation | Rigorously verified and validated per internal process and FDA/IEC standards (e.g., FDA guidance for software, IEC 62304). | Test results indicate compliance with predetermined specifications and standards. |
| Electrical Safety | Complies with IEC 60601-1:2005, Am1:2012 and ANSI/AAMI ES 60601-1:2005, Am2:2010. | Test results indicate compliance with standards. |
| Electromagnetic Compatibility (EMC) | Complies with IEC 60601-1-2:2007 and FCC 47 CFR §15. | Test results indicate compliance with standards. |
| Bench Verification (Performance Testing) | Complies with internal documentation and FDA Guidance for rTMS systems. | Test results indicate compliance with predetermined specification and applicable standard. |
| Usability Validation | Complies with IEC 60601-1-6:2010 and IEC 62366:2007. | Test results indicate compliance with applicable standards. |
Study Details:
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Sample Size used for the Test Set and Data Provenance:
- This submission is a 510(k) premarket notification primarily demonstrating substantial equivalence for a therapeutic device (rTMS system for MDD), specifically adding a new treatment protocol (iTBS).
- The document does not describe a specific clinical "test set" or study in the sense of an independent data set used to evaluate a diagnostic algorithm's performance. Instead, it relies on:
- Bench testing and verification/validation activities against technical standards (listed in the table above).
- Comparison to a legally marketed predicate device (Tonica Electronik A/S / Mag Vita TMS Therapy System w/ Theta Burst Stimulation, K173620), which already had the iTBS protocol cleared.
- Comparison to its own previously cleared device version (K171902) to show that existing features remain unchanged or are consistent.
- Therefore, there's no "sample size" for patients/cases in a typical AI/diagnostic study sense within this document for a "test set." The document focuses on technical and safety equivalence.
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Number of Experts used to establish the Ground Truth for the Test Set and Qualifications of those Experts:
- Not applicable in the context of this 510(k) submission. This is not a study assessing the diagnostic performance of an AI against expert ground truth. The "ground truth" for this device's function is its ability to deliver the specified magnetic stimulation parameters accurately and safely, and for the clinical efficacy of this type of therapy for MDD, which is established by larger clinical trials for the class of devices and specific protocols (e.g., those reviewed for the predicate device).
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Adjudication Method for the Test Set:
- Not applicable. No external "test set" requiring expert adjudication is described.
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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 device is a therapeutic rTMS system, not a diagnostic AI system intended to assist human readers. Therefore, an MRMC study is not relevant to this submission.
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If a standalone (i.e. algorithm only without human-in-the-loop performance) was done:
- Not applicable in the traditional sense of a diagnostic algorithm. The device itself (the Nexstim NBT System 2) operates based on software control and delivered TMS pulses. Its "standalone performance" is implicitly demonstrated through the various verification and validation activities (software, electrical safety, EMC, bench testing), which confirm it functions according to its predetermined specifications, independently of a human operator, in terms of delivering the therapy. The clinical use always involves a trained medical professional.
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The type of ground truth used (expert consensus, pathology, outcomes data, etc.):
- The "ground truth" for this submission is multi-faceted, aligning with the nature of a therapeutic device and a substantial equivalence review:
- Technical Specifications: The core "ground truth" for the device itself is its adherence to specified physical parameters (magnetic field intensity, frequency, pulse length, etc.) and compliance with recognized industry standards (IEC, ISO, FDA guidance) for safety and performance. This is verified through bench testing and engineering evaluations.
- Predicate Device Performance: The "ground truth" for clinical effectiveness of the iTBS protocol is based on the established performance of the predicate device (K173620) which already had clearance for this protocol. The submission argues that since the proposed device's technical characteristics for delivering iTBS are equivalent, its clinical effect would also be equivalent.
- Clinical Effectiveness of rTMS for MDD: The broader "ground truth" for the treatment of Major Depressive Disorder with rTMS is established by clinical outcomes data from pivotal studies that led to the approval of the predicate device and other similar rTMS systems for MDD. This document refers to the established indication for use for rTMS in MDD, rather than presenting new clinical trial data for this specific device's efficacy beyond the established equivalence.
- The "ground truth" for this submission is multi-faceted, aligning with the nature of a therapeutic device and a substantial equivalence review:
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The sample size for the training set:
- Not applicable. This document describes a medical device seeking 510(k) clearance, not an AI/machine learning algorithm undergoing training with a specific dataset. The software is developed and verified via traditional software engineering processes, not "trained."
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How the ground truth for the training set was established:
- Not applicable. As there is no "training set" for an AI/ML algorithm, no ground truth needed to be established in that context.
§ 882.5805 Repetitive transcranial magnetic stimulation system.
(a)
Identification. A repetitive transcranial magnetic stimulation system is an external device that delivers transcranial repetitive pulsed magnetic fields of sufficient magnitude to induce neural action potentials in the prefrontal cortex to treat the symptoms of major depressive disorder without inducing seizure in patients who have failed at least one antidepressant medication and are currently not on any antidepressant therapy.(b)
Classification. Class II (special controls). The special control is FDA's “Class II Special Controls Guidance Document: Repetitive Transcranial Magnetic Stimulation System.” See § 882.1(e) for the availability of this guidance document.