(260 days)
The NVM5® System is a medical device that is intended for intraoperative neurophysiologic monitoring during spinal surgery. The device provides information directly to the surgeon, to help assess a patient's neurophysiologic status. NVMS provides this information by electrically stimulating nerves via electrodes located on surgical accessories and monitoring electromyography (EMG), transcranial or lumbar motor evoked potential (MEP), or somatosensory evoked potential (SSEP) responses of nerves. The System also integrates Bendini® software used to locate spinal implant instrumentation for the placement of spinal rods.
· XLIF (Detection) - The XLIF (Detection) function allows the surgeon to locate and evaluate spinal nerves, and is used as a nerve avoidance tool.
· Basic & Dynamic Screw Test - The Screw Test functions allow the surgeon to locate and evaluate spinal nerves by providing proximity information before, during or after bone preparation and placement of bone screws.
· Free Run EMG - The Free Run EMG function identifies spontaneous EMG activity of spinal nerves by continually displaying a live stream waveform of any mechanically induced myotome contractions.
· Twitch Test (Train of Four) - The Twitch Test Function allows the surgeon to assess moderate degrees of neuromuscular block in effect by evaluating muscle contraction following a train of four stimulation pulses.
· MEP - Transcranial or lumbar (i.e., conus in region of L1-L2) stimulation techniques for motor evoked potentials are used to assess for acute dysfunction in axonal conduction of the corticospinal tract and peripheral nerves. The MEP function provides an adjunctive method to allow the surgeon to motor pathway integrity during procedures with a risk of surgically induced motor injury.
· SSEP - The SSEP function allows the surgeon to assess sensory spinal cord function in surgical procedures during which the spinal cord is at risk.
· Remote Reader - The Remote Reader function provides real time remote access to the NVMS System for a monitoring physician outside of the operating room.
· Guidance - The Guidance function is intended as an aid for use in either open or percutaneous pedicle cannulation procedures in the lumbar and sacral spine (LI-SI) of adult patients, and when used in conjunction with radiographic imaging and EMG, allows the surgeon to assess the angulation of system accessories relative to patient spinal anatomy for the creation of a cannulation trajectory for bone screw placement.
· Bendini - The Bendini Spinal Rod Bending function is used to locate spinal implant system instrumentation (screws, hooks) to determine their relative location to one another to generate bend instructions to shape a spinal rod. A surgeon is able to use those instructions and bend a rod using the Bendini Bender, a mechanical rod bender.
The NVM5 System is a medical device that is intended for intraoperative neurophysiologic monitoring during spinal surgery. The device provides information directly to the surgeon, to help assess a patient's neurophysiologic status. NVM5 provides this information by electrically stimulating nerves via electrodes located on surgical accessories and monitoring electromyography (EMG), motor evoked potential (MEP) or somatosensory evoked potential (SSEP) responses of nerves. Moreover, a Twitch Test function is utilized to test the ability of the nerve to respond, or contract, following four stimulation pulses to determine the presence of neuromuscular block.
Additionally, the NVM5 System includes an integrated stereotactic guidance system (NVM5 Guidance) to support the delivery of pedicle screws during EMG monitoring. The System also integrates Bendini® software used to locate spinal implant instrumentation for the placement of spinal rods. Lastly, the system also offers an optional screen sharing application to allow a secondary physician to remotely view the events represented on the NVM5 user interface. In summary, the NVM5 System includes the following six (6) software functionalities / modalities:
-
- Electromyography (EMG)
-
- Motor Evoked Potential (MEP)
-
- Somatosensory Evoked Potential (SSEP)
-
- Remote Reader
-
- Guidance
-
- Bendini
The NVM5 System hardware consists of a Patient Module (PM) and computer, as well as accompanying accessory components which consist of an assortment of disposable conductive probes, electrodes, and electrode leads.
Here's a summary of the acceptance criteria and the study that proves the NuVasive NVM5 System meets them, based on the provided text:
1. Table of Acceptance Criteria and Reported Device Performance
The submission primarily focuses on demonstrating substantial equivalence to a predicate device (K123307, also a NuVasive NVM5 System) rather than defining explicit quantitative acceptance criteria as might be seen for a novel device. The "acceptance criteria" are implied by the claim of substantial equivalence and meeting design specifications.
| Acceptance Criteria (Implied by Substantial Equivalence and Design Specs) | Reported Device Performance (Subject Device) |
|---|---|
| Intended Use / Indications for Use: | Identical to predicate device, including: |
| - Intraoperative neurophysiologic monitoring during spinal surgery | - Intraoperative neurophysiologic monitoring during spinal surgery |
| - Assess patient's neurophysiologic status | - Assess patient's neurophysiologic status |
| - Electrical stimulation of nerves via electrodes | - Electrical stimulation of nerves via electrodes |
| - Monitoring EMG, MEP (transcranial or lumbar), SSEP responses | - Monitoring EMG, MEP (transcranial or lumbar), SSEP responses |
| - Integration of Bendini software for spinal rod placement | - Integration of Bendini software for spinal rod placement |
| - XLIF (Detection) function for nerve localization/avoidance | - XLIF (Detection) function for nerve localization/avoidance |
| - Basic & Dynamic Screw Test for nerve proximity information | - Basic & Dynamic Screw Test for nerve proximity information |
| - Free Run EMG for spontaneous EMG activity | - Free Run EMG for spontaneous EMG activity |
| - Twitch Test (Train of Four) for neuromuscular block assessment | - Twitch Test (Train of Four) for neuromuscular block assessment |
| - MEP for assessing axonal conduction/motor pathway integrity | - MEP for assessing acute dysfunction in axonal conduction of corticospinal tract and peripheral nerves, and monitoring spinal cord and motor pathway integrity (Expanded "Transcranial or lumbar" for MEP) |
| - SSEP for assessing sensory spinal cord function | - SSEP for assessing sensory spinal cord function |
| - Remote Reader function for remote access to system | - Remote Reader function for remote access to system |
| - Guidance function for pedicle cannulation in lumbar/sacral spine | - Guidance function (expanded from lumbar/sacral to thoracolumbar and sacral spine (L1-S1)) for pedicle cannulation, assessing angulation of accessories relative to patient spinal anatomy for cannulation trajectory with radiographic imaging and EMG. |
| - Bendini function for spinal rod bending instructions | - Bendini function for locating spinal implant instrumentation and generating bend instructions for spinal rods. |
| Technological Characteristics: | Identical to predicate device, with minor modifications shown to be substantially equivalent: |
| - Software Modalities/Functionalities | - XLIF (Detection), Basic & Dynamic Screw Test, Free Run EMG, Twitch Test, MEP, SSEP, Remote Monitoring, Guidance, Bendini (Identical, with MEP indicating both transcranial and lumbar) |
| - Algorithms | - Identical algorithms as predicate. |
| - Total Available Channels | - 32 |
| - Headbox/Patient Module | - Yes |
| - IEC 60601-1 Compliant | - Yes |
| - Full Scale View Range | - $\pm 0.5 \mu V$ to $\pm 8mV$ |
| - Frequency Response | - 3 Hz to 4.8 kHz |
| - User Interface | - NuVasive-supplied computer or NuVasive provided touch screen and [optional] keyboard/mouse |
| - Remote Monitoring | - Yes |
| - Train of Four Testing | - Yes |
| - Needle Electrodes | - Various |
| - Surface Electrodes | - Various |
| - Electrode Leads/Stimulating Probes/Recording Channels | - Various |
| - EMG Modalities | - XLIF (Detection), Basic & Dynamic Screw Test, Free Run EMG, Twitch Test |
| - Stimulation Modes (Automatic/Manual) | - Automatic (XLIF, Basic & Dynamic Screw Test), Manual (Free Run EMG, SSEP), Manual & Automatic (Twitch Test, MEP) |
| - Threshold Values for Color Alerts | - Yes (Identical to predicate where applicable) |
| - Audio feedback | - Yes |
| - Screen-sharing accessibility | - Remote Monitoring |
| - Guidance Clinical Use & Performance Requirements | - Requires input from CT, MRI, or radiographic images; assists surgeon in pedicle cannulation based on user-predefined trajectory; integrated with EMG stimulation. Angular tolerance of $\pm 2^\circ$, confirmation of alignment to pre-planned trajectory, seamlessly integrated with insulated Jamshidi Needle. (Identical to predicate) |
| - Bendini Components & User Interface | - Optical (IR) tracking technology system, IR tracking instruments, computer. Touch screen, graphical user interface, and audio. Instrumentation: IR Digitizer (with integrated passive spheres), Rod Bender. (Identical to predicate) |
| Safety and Performance (general): | Met or exceeded the performance of the predicate device. "The results of these studies showed that the subject NVM5® System meets or exceeds the performance of the predicate device, and the device was therefore found to be substantially equivalent." |
| - Biocompatibility (for Dual Surface Electrodes) | - Passed ISO 10993 testing for cytotoxicity, sensitization, and irritation/intracutaneous. |
| - Software Validation | - Verification and Validation Testing according to Software Requirements Specifications, including modifications. Regression Testing. |
| - System Integration (Bendini) | - Bendini System Integration Testing. |
| - Functional Testing (Dual Surface Electrodes) | - Dual Surface Electrode Functional Testing. |
2. Sample Sizes Used for the Test Set and Data Provenance
The document describes "Nonclinical testing" including "NVM5 System Verification and Validation Testing," "NVM5 System software Regression Testing," "Bendini System Integration Testing," "Dual Surface Electrode Functional Testing," and "ISO 10993 Biocompatibility Testing."
- Sample Size for Test Set: The exact sample sizes for each of these nonclinical tests are not specified in the provided text. The testing focuses on system-level verification and validation.
- Data Provenance: The studies are described as "Nonclinical testing" and internal "verification and validation testing." There is no mention of data provenance in terms of country of origin or whether it was retrospective or prospective clinical data, as this was primarily a technical and software update submission, not a new clinical study.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Qualifications
The document does not mention the use of experts to establish a "ground truth" for the test set in the context of clinical accuracy or interpretation during these nonclinical tests. The tests performed are engineering-focused:
- Software verification against specifications.
- Regression testing to ensure changes didn't break existing functionality.
- Integration testing.
- Functional testing of a component (Dual Surface Electrode).
- Biocompatibility testing against ISO standards.
For such tests, "ground truth" would typically refer to the expected outputs or behavior defined by the design specifications or established by standard test methods.
4. Adjudication Method for the Test Set
Since the testing described is nonclinical performance, software, and biocompatibility testing, an adjudication method in the sense of reconciling expert opinions on clinical cases (e.g., 2+1, 3+1) is not applicable and not mentioned in the document. The tests would likely have pass/fail criteria based on predefined engineering or regulatory standards.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
A MRMC comparative effectiveness study was not done or mentioned. The submission is focused on demonstrating substantial equivalence through nonclinical performance and software testing for a modified device, not a comparative clinical study with human readers.
6. Standalone (Algorithm Only Without Human-in-the-Loop) Performance
The studies described are primarily standalone testing of the device's functions and components, rather than human-in-the-loop performance. The "human-in-the-loop" aspect is implicit in the intended use where the device provides information to the surgeon for assessment. The software and hardware functionalities were tested independently to ensure they meet specifications and perform as expected.
7. Type of Ground Truth Used
The ground truth used for the nonclinical tests would be:
- Design Specifications: For the NVM5 System Verification and Validation and Software Regression Testing, the "ground truth" would be the predefined Software Requirements Specifications.
- Predicate Device Performance: For demonstrating substantial equivalence, the "ground truth" is the established performance and characteristics of the predicate NuVasive NVM5 System (K123307).
- Standard Test Methods: For Biocompatibility Testing, the "ground truth" is defined by the ISO 10993 standards and their acceptance criteria.
- Expected Functional Output: For Bendini System Integration Testing and Dual Surface Electrode Functional Testing, the "ground truth" would be the expected functional outputs and interactions defined by the system design.
8. Sample Size for the Training Set
The document does not provide information about a specific "training set" or its sample size. This type of information is typically relevant for submissions involving machine learning algorithms that are trained on data. While the NVM5 System contains "algorithms," they are described as "identical algorithms as predicate," implying established, deterministic algorithms rather than newly trained AI models. The testing described is verification and validation of these established algorithms and the system as a whole.
9. How the Ground Truth for the Training Set Was Established
As no specific "training set" for machine learning is mentioned, the method for establishing its ground truth is not applicable and not described in this document.
§ 874.1820 Surgical nerve stimulator/locator.
(a)
Identification. A surgical nerve stimulator/locator is a device that is intended to provide electrical stimulation to the body to locate and identify nerves and to test their excitability.(b)
Classification. Class II.