(179 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. NVM5 provides this information by electrically stimulating nerves via electrodes located on surgical accessories and monitoring electromyography (EMG), transcranial motor evoked potential (TcMEP) or somatosensory evoked potential (SSEP) responses of nerves.
- 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 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.
- TcMEP Transcranial stimulation techniques for motor evoked potentials are used to assess for acute dysfunction in axonal conduction of the corticospinal tract. The TcMEP function provides an adjunctive method to allow the surgeon to monitor spinal cord 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 NVM5 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 spine 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.
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), transcranial motor evoked potential (TcMEP) or somatosensory evoked potential (SSEP) responses of the muscle groups imnervated by the nerves. Moreover, a Twitch Test ("Train of Four") 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. Lastly, the system also offers an optional screen sharing application (Remote Monitoring) to allow a secondary physician to remotely view the events represented on the NVM5 user interface. In summary, the NVMS System includes the following five (5) software functionalities / modalities: 1. Electromyography (EMG) 2. Transcranial Motor Evoked Potential (TcMEP), or simply MEP 3. Somatosensory Evoked Potential (SSEP) 4. Remote Monitoring 5. Guidance. The NVM5® System hardware consists of a Patient Module (PM) and a Control Unit (CU) comprised of an embedded computer with touch screen controls and an interface card, as well as accompanying accessory components which consist of an assortment of disposable conductive probes, electrodes, and electrode leads.
The NuVasive NVM5 System is a medical device intended for intraoperative neurophysiological monitoring during spinal surgery. The system provides information directly to the surgeon to help assess a patient's neurophysiologic status by electrically stimulating nerves and monitoring electromyography (EMG), transcranial motor evoked potential (TcMEP), or somatosensory evoked potential (SSEP) responses of nerves.
Here's an analysis of the acceptance criteria and the study that proves the device meets them:
1. Table of Acceptance Criteria and Reported Device Performance
The provided document describes the acceptance criteria and reported device performance by comparing the NuVasive NVM5 System with predicate devices. The primary method for demonstrating acceptance is through substantial equivalence to legally marketed predicate devices, supported by nonclinical performance testing.
| Feature/Specification | Acceptance Criteria (Predicate Device K050438 - StealthStation®) | Reported Device Performance (NuVasive NVM5 Guidance - K112718) |
|---|---|---|
| Intended Use / Indications for Use (Guidance Function) | "Precisely locating anatomical structures in either open or percutaneous procedures... for any medical condition in which the use of stereotactic surgery may be appropriate, and where reference to a rigid anatomical structure... can be identified relative to a CT or MR based model, fluoroscopy images, or digitized landmarks of the anatomy." (Specifically for pedicle cannulation) | "Aid for use in percutaneous pedicle cannulation in the lumbar spine of adult patients, and in conjunction with radiographic imaging that allows the surgeon to assess the angulation of accessories relative to patient spinal anatomy for the creation of a cannulation trajectory for bone cement." |
| Input Data | Requires input derived from CT, MRI, or radiographic images | Requires input derived from CT, MRI, or radiographic images |
| Assistance to Surgeon | Intended to assist the surgeon in cannulating the pedicle based on user predefined trajectory Integrated with EMG stimulation | Intended to assist the surgeon in cannulating the pedicle based on user predefined trajectory with EMG stimulation |
| Sensing Technology | References angular and position sensing technology coupled with associated tracking instruments | References angular sensing technology coupled with associated tracking instruments |
| C-Arm Reticle | Utilizes a C-Arm Reticle with radio dense markers | Utilizes a C-Arm Reticle with radio dense markers |
| Scientific Principles (Sensing DOF) | Uses infrared technology to capture positional and rotational information via 6 DOF (x, y, z, rx, ry, rz) data. Displays the location and orientation (positional and rotational information in the x, y, and z planes) of instruments in real time merged with pre-operatively obtained images of patient anatomy. | Uses accelerometers to sense angular measurements based on gravity by collecting 2 degrees of freedom (DOF) (rx, ry) data. Displays instrument orientation only (rotational information in the x and y planes only) with respect to gravity. |
| Performance Requirements | Angular tolerance of ±2°. Confirmation of alignment to pre-planned trajectory. Seamlessly integrated with an insulated Jamshidi Needle. | Angular tolerance of ±2°. Confirmation of alignment to pre-planned trajectory. Seamlessly integrated with an insulated Jamshidi Needle. |
| Conformance with Standards | IEC 60601-1, IEC 60601-1-2 | IEC 60601-1, IEC 60601-1-2 |
Conclusion on Equivalence: The document states "Yes – the Guidance function has limited indications compared to the predicate. The reduced degree of data collected by Guidance is still deemed substantially equivalent since it is used in conjunction with fluoroscopic imaging, not indicated for used by the predicate StealthStation. The amount of data collected by Guidance is sufficient to provide angular outputs to compare against the angular inputs identified by the user as the planned trajectory, considering that intraoperative radiographic imaging is used to confirm the starting point and correct trajectory of the cannulation needle." This indicates the device meets the criteria for its specified (more limited) use.
Performance Data for other functionalities (EMG, TcMEP, SSEP, accessories): Demonstrated through compliance with IEC 60601-1, IEC 60601-2-40, IEC 60601-1-2, and various accessory-specific tests (impedance, current density, electrical performance, biocompatibility, sterilization, penetration/friction).
2. Sample Size Used for the Test Set and the Data Provenance
The document does not explicitly state a sample size for a test set in the conventional sense of a clinical study with patients. The performance data primarily relies on:
- Nonclinical Bench Testing: This includes electrical safety, compatibility, impedance, current density, electrical performance, durability, fluid interference, biocompatibility, sterilization validation, penetration, and friction testing. These tests are typically conducted in a laboratory setting.
- Comparison to Predicate Devices: The primary method for proving substantial equivalence.
- Reference to Published Clinical Literature: For the Guidance performance testing, two published clinical literature articles are referenced:
- "Accuracy of percutaneous lumbar pedicle screw placement using the oblique or 'owl's-eve' view and novel guidance technology" (J Neurosurg Spine. 2010)
- "Improving accuracy and reducing radiation exposure in minimally invasive lumbar interbody fusion" (J Neurosurg Spine, 2010)"
The document does not provide details on the data provenance (e.g., country of origin, retrospective or prospective) for any clinical data that might have contributed to these published works, nor does it specify if a dedicated prospective test set was used for the NVM5 System itself beyond the bench testing.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and the Qualifications of Those Experts
This information is not provided in the document. The document describes nonclinical performance testing and refers to published clinical literature, but it does not detail the methodology for establishing ground truth or the involvement/qualifications of experts in the context of a "test set" for the NVM5 device.
4. Adjudication Method for the Test Set
This information is not provided in the document. Given that the testing primarily involves nonclinical bench tests and comparison to predicate devices, a formal adjudication method for a "test set" in the context of clinical ground truth is not described.
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
A Multi-Reader Multi-Case (MRMC) comparative effectiveness study is not mentioned in the document. The device is for intraoperative neurophysiological monitoring and guidance, which directly provides information to the surgeon. It is not an AI-assisted diagnostic imaging interpretation tool where human readers assess cases with and without AI.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done
The document describes the performance of the NVM5 System as a device providing information to the surgeon for intraoperative neurophysiologic monitoring and guidance. The "Guidance" function explicitly states it is "an aid for use... when used in conjunction with radiographic imaging and EMG, allows the surgeon to assess the angulation..." This indicates it's designed to be used with a human (surgeon) in the loop and does not refer to a standalone, algorithm-only performance assessment in the absence of human interaction or interpretation.
7. The Type of Ground Truth Used
For the Guidance function's accuracy testing, the ground truth appears to be based on:
- Engineering measurements: Demonstrating "equivalent degrees of variance" between the accelerometer-based NVM5 Guidance function and the infrared tracking from the StealthStation predicate device.
- Clinical Outcomes from Literature: Supplemented by the results from two referenced clinical literature articles concerning the accuracy of pedicle screw placement and radiation exposure in minimally invasive lumbar interbody fusion. While these articles would have used surgical outcomes or imaging (e.g., post-op CT) to establish ground truth for screw placement accuracy, the specific ground truth methodology for these studies is not detailed in the 510(k) summary itself.
For other functions (EMG, TcMEP, SSEP), the ground truth is implicitly established through:
- Compliance with electrical safety and performance standards (IEC 60601-x series): This ensures the device reliably measures and stimulates as expected for neurophysiological monitoring.
- Bench testing of accessories: Ensures components meet specifications for electrical properties, biocompatibility, and sterilization.
8. The Sample Size for the Training Set
The document pertains to a 510(k) submission for a medical device that monitors neurophysiological responses and aids in surgical guidance. It does not describe a machine learning or AI algorithm in a way that would involve a distinct "training set." Therefore, a sample size for a training set is not applicable and not provided.
9. How the Ground Truth for the Training Set Was Established
As there is no mention of a machine learning or AI algorithm requiring a training set, the establishment of ground truth for such a set is not applicable and not provided. The ground truth for the device's performance, as described, is based on engineering principles, compliance with medical device standards, and substantial equivalence to established predicate devices.
§ 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.