(185 days)
The Magstim D702 coil is a stimulating coil intended for use with the Magstim® 2002 Stimulating Unit or the Magstim® Rapid2 Stimulating Unit for the purpose of peripheral nerve stimulation for diagnostic purposes. The coil is an accessory to the Magstim ® 2002 Stimulating Unit, and the coil is an accessory to the Magstim® Rapid2 Stimulating Unit.
The Magstim D702 coil is designed for use with the Magstim 2002 stimulator or the Magstim Rapid2 stimulator. The Magstim D70 coil provides a method of non-invasively delivering its output to a target such as the peripheral nerves. Discharge current through the coil generates a brief, high intensity magnetic pulse. When the coil is applied to a conductive medium such as the human body, eddy currents are produced in the medium by electromagnetic induction. This stimulation method enables deep and otherwise inaccessible nerves to be stimulated easily and relatively painlessly. In addition, no skin preparation is required and stimulation can be achieved through clothing. The coil is a non-sterile reusable device intended for multipatient use. The coil is transportable and is intended to be used in a laboratory, consulting room or equivalent environment. The coil is intended for short-term patient contact where single or cumulative contact does not exceed 24 hours.
The provided text is a 510(k) Summary for the Magstim D702 Coil, a medical device for peripheral nerve stimulation. It details how the device is considered substantially equivalent to predicate devices, primarily through engineering and performance testing, rather than studies involving human readers or extensive clinical trials.
Here's an analysis of the acceptance criteria and study information, based on the provided text:
1. Table of Acceptance Criteria and Reported Device Performance
| Characteristic | Acceptance Criteria (Predicate Device) | Reported Device Performance (Magstim D702 Coil) |
|---|---|---|
| Intended Use | Peripheral nerve stimulation for diagnostic purposes | Peripheral nerve stimulation for diagnostic purposes |
| Indications for Use | Peripheral nerve stimulation for diagnostic purposes | Peripheral nerve stimulation for diagnostic purposes |
| Average Inductance | 15.50 µH | 13 µH |
| Number of Turns | 9 | 11 |
| Number of Windings | 2 | 2 |
| Wire Cross Sectional Area | 9 mm² | 12.5 mm² |
| Coil Cable Length | 2.0m | 1.8m |
| Manner of Stimulation | Peripheral | Peripheral |
| Peak Magnetic Field (Magstim 2002) | 1.7T (or 1.2T for Rapid2) | 2.1T |
| Peak Magnetic Field (Magstim Rapid2) | 1.2T | 1.2T |
| Number of pulses before exceeding max operating temp (Magstim 2002) | 110 | >290 |
| Number of pulses before exceeding max operating temp (Magstim Rapid2) | >600 (Rapid1) / 110 | >600 (Rapid1) - Note: Discrepancy in table for Rapid2 vs Rapid1 |
| Cooling | No | No |
| Multiple Use | Yes | Yes |
| Sterile | No | No |
| Weight | 1.8kg | 1.95kg |
| Integral Adapter | No | Yes |
Interpretation of "Acceptance Criteria": In this context, the "acceptance criteria" are not explicitly stated as numerical thresholds for success (e.g., "must achieve X% accuracy"). Instead, the acceptance criteria are implicitly defined by demonstrating that the modified device (Magstim D702 Coil) is substantially equivalent to the predicate devices. This means that:
- Its intended use and indications for use are the same.
- Its technological characteristics are similar, and any differences do not raise new questions of safety or effectiveness.
- Testing shows performance is comparable or improved and meets applicable safety standards.
The specific performance metrics for inductance, peak magnetic field, and number of pulses before overheating are compared directly to the predicate device's characteristics, and the device is deemed acceptable if these differences are understood and do not negatively impact safety or effectiveness, or in some cases, show improvement (e.g., higher pulse count due to better heat dissipation).
2. Sample Size Used for the Test Set and Data Provenance
The document does not describe "test sets" in the context of patient data or clinical imaging. The "testing activities" mentioned involved:
- Safety testing from risk analysis.
- Laboratory studies for electrical safety testing.
- EMC testing.
- Usability testing for consumer accuracy (this might involve human interaction but isn't elaborated as a clinical study).
- Magnetic field measurement testing.
Therefore, there is no stated sample size for a patient test set or data provenance because the evaluation was primarily engineering and performance-based, comparing device specifications to a predicate. It was not a study involving patient data.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Qualifications
Not Applicable. The evaluation was engineering-focused. There was no "ground truth" derived from expert consensus on medical images or clinical outcomes from a patient test set.
4. Adjudication Method for the Test Set
Not Applicable. As there was no patient test set requiring expert interpretation or consensus, there was no adjudication method used.
5. If a Multi Reader Multi Case (MRMC) Comparative Effectiveness Study was done
No. The document does not describe an MRMC study. The comparison is between the new device and predicate devices based on engineering specifications and laboratory testing, not human reader performance with or without AI assistance.
6. If a Standalone (i.e. algorithm only without human-in-the loop performance) was done
Not Applicable. This device is a hardware component (a stimulating coil) for a medical stimulator, not an algorithm. Therefore, "standalone algorithm performance" is not relevant. The device's 'performance' is its ability to generate magnetic fields and deliver pulses according to its specifications.
7. The Type of Ground Truth Used
The "ground truth" in this context is the established performance characteristics and safety profiles of the legally marketed predicate devices, along with relevant international standards (IEC 60601-1, IEC 60601-1-2, ISO 10993-1). The new device's performance was measured against these benchmarks through laboratory testing.
8. The Sample Size for the Training Set
Not Applicable. As this is a hardware device and not an AI/ML algorithm that requires training data, there is no "training set."
9. How the Ground Truth for the Training Set was Established
Not Applicable. See point 8.
§ 882.1870 Evoked response electrical stimulator.
(a)
Identification. An evoked response electrical stimulator is a device used to apply an electrical stimulus to a patient by means of skin electrodes for the purpose of measuring the evoked response.(b)
Classification. Class II (performance standards).