(135 days)
The Stimwave Technologies Incorporated Freedom Spinal Cord Stimulator (SCS) System is intended as the sole mitigating agent, or as an adjunct to other modes of therapy used in a multidisciplinary approach for chronic, intractable pain of the trunk and/or lower limbs, including unilateral pain. The FRT4-A001 device is solely used for trial stimulation (no longer than 30 days) of the permanent FRE4-A001 device.
The Stimwave Technologies Incorporated (Stimwave) Freedom Spinal Cord SCS System (System) is used for spinal column neural stimulation to provide therapeutic relief for chronic, intractable pain of the trunk and/or lower limbs including unilateral or bilateral pain. The therapy utilizes pulsed electrical current to create an electrical energy field that acts on nerves near the dorsal column of the spine. The System is comprised of an implantable stimulator (Freedom-4 Stimulator) and an externally worn transmitter (Wearable Antenna Assembly (WAA)) to power the device. The System is implanted only following a successful trial period with the Trial Freedom-4 Stimulator.
The document describes the Stimwave Technologies Incorporated Freedom Spinal Cord Stimulator (SCS) System and provides information to support its substantial equivalence to legally marketed predicate devices.
Here's an analysis of the acceptance criteria and supporting studies, formatted as requested:
Acceptance Criteria and Reported Device Performance
The document does not explicitly present a table of acceptance criteria with specific numerical targets and corresponding reported device performance values in a side-by-side format. Instead, it describes compliance with various national and international standards and design requirements through a series of non-clinical tests. The "reported device performance" is generally stated as having "passed," "met the criteria," or being "lower/higher than the allowable limit."
However, a comparison table (Table 5A) is provided that compares the technological characteristics of the Stimwave Freedom SCS System with three predicate devices. This table implicitly defines "acceptance" as being similar to or within the range of these predicate devices for many parameters.
Implicit Acceptance Criteria and Reported Performance (derived from Table 5A and non-clinical testing sections):
| Acceptance Criteria Category | Implicit Acceptance Criteria / Standard | Reported Device Performance |
|---|---|---|
| General Device Characteristics | Same intended use, implant site, environmental use, intended clinician/user, electrode material, stimulator body material, method of introduction, tissue contact, sterilization, labeling, package. | All "Same as Freedom" across predicate devices. |
| Physical Dimensions | ||
| - Stimulator Length | Comparable to predicate devices (30-110 cm) | 45 centimeters (within range) |
| - Diameter | Comparable to predicate devices (1.3-1.37 mm) | 1.35 millimeters (within range) |
| - Electrode Array Length | Comparable to predicate devices (24.0 mm) | 24.0 millimeters (same) |
| - No. of Electrodes | Comparable to predicate devices (4 or 8) | 4 (within range) |
| - Electrode Length | Comparable to predicate devices (3.0 mm) | 3.0 millimeters (same) |
| - Electrode Spacing | Comparable to predicate devices (4.0 mm) | 4.0 millimeters (same) |
| - Electrode Surface Area | Comparable to predicate devices (12.25 mm² - ~13 mm²) | 12.72 mm² (comparable) |
| Electrical Performance Parameters | Comparable to predicate devices within ranges/values. | See Table 5A for detailed comparison across various parameters like Pulse Frequency, Pulse Width, Current/Voltage Regulation, Output Voltage/Current, Waveform, Pulse Shape, Current/Charge/Power Densities, Net Charge, Output Power. Generally comparable or within acceptable ranges. |
| Material Biocompatibility | Compliance with ISO 10993-1:2009 and Blue Book Memorandum G95-1 for an implant device in contact with tissue/bone for cytotoxicity, sensitization, irritation, intracutaneous reactivity, acute systemic toxicity, implantation (4, 8, and 13 weeks), and subchronic toxicity. | "No negative impacts" from materials, meets biological safety and compatibility requirements. |
| Temperature Change (Storage) | Functional, safe rating following post visual inspection. Compliance with AAMI ANSI ISO 14708-3:2008. | Stimulator was functional, received a safe rating, passed change of temperature testing. External unit met passing criteria. |
| Atmospheric Pressure Change | Functional following post testing functionality inspection. Compliance with AAMI ANSI ISO 14708-3:2008. | Stimulator was functional, passed atmospheric pressure change testing. External unit met passing criteria. |
| MRI Safety - RF Induced Heating | Maximum temperature increase lower than allowable limit for 1.5T and 3T MRI. Compliance with ASTM F2182-11a. | Produced a maximum temperature increase lower than the allowable limit for 1.5T and 3T MRI, thus passed. |
| MRI Safety - Image Artifacts | Maximum measured artifact size lower than allowable limit for 3T MRI. Compliance with ASTM F2119-07. | Produced a maximum measured artifact size lower than the allowable limit for 3T MRI, thus passed. No detrimental image artifacts. |
| MRI Safety - Induced Displacement | Significantly lower deflection value than allowable test limit. Compliance with ASTM F2052-06. | Produced a significantly lower deflection value than the allowable test limit. Passed ASTM acceptance criteria for deflection angle. |
| MRI Safety - Induced Torque | Lowest score (no torque) according to qualitative scale. Compliance with ASTM F2213-06. | Produced the lowest score, no torque. Will not present additional risk. |
| Electrical Safety - Leakage Current | Zero leakage current on all tested paths for all samples. | Produced zero leakage current. |
| Stimulator Insertion/Withdrawal | Less than 2.5N of insertion or withdrawal force. No damage. | Required less than 2.5N; no damage. |
| Stimulator Body Flex | No visible damage to stimulator body or components. | Passed all criteria, no visible damage. |
| Destructive Pull Test | Maximum elongation of 0.5% (well below 5% limit). | Maximum elongation 0.5% (well below test limit of 5%). |
| External Defibrillation Exposure | Verified to function as outlined. | Verified to function as outlined. |
| External Unit Robustness | Withstand expected damage (push, drop, impact, mold stress relief). Compliance with IEC 60601-1. | Met passing criteria, no physical damage, fully operational. |
| Electromagnetic Compatibility (EMC) | Met all acceptance criteria for emissions, magnetic fields, immunity (electrostatic discharge, radiated RF fields, electrical fast transients/bursts). Compliance with IEC 60601-1-2. | Met all acceptance criteria and operated within test limits. |
| Ingress of Water/Particulate Matter | Met passing criteria of visual and functional inspections. Compliance with IEC 60529. | Met passing criteria, no physical damage, fully operational. |
| Software Verification | Passed all verification tests outlined and design requirements met. | Passed all verification tests. |
Study Details
The document refers to a "submission" rather than a single specific study. The evidence for meeting acceptance criteria is predominantly based on non-clinical performance testing and a comparison to predicate devices.
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Sample size used for the test set and the data provenance:
- Test Set Sample Size: Not explicitly stated as a separate "test set" in the context of device performance, but rather individual components were tested according to various standards. For example, "all tested samples" for leakage current and "all tested stylets in all tested stimulator samples" for insertion/withdrawal. The exact number of units/components tested for each non-clinical test is not specified.
- Data Provenance: The testing was conducted by Stimwave Technologies Incorporated to verify compliance with national and international standards (AAMI ANSI ISO, ASTM, IEC). The data is prospective in the sense that the testing was performed on the Stimwave Freedom SCS System components specifically for this submission. The "data provenance" regarding the location of testing is not specified, but it's presumed to be within the manufacturer's testing facilities or accredited laboratories.
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Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
- This question is not applicable in the typical sense for this submission. The "ground truth" for the non-clinical tests is established by the specific requirements and acceptance criteria of the referenced national and international standards (e.g., ISO, ASTM, IEC). These standards are developed and recognized by expert bodies in their respective fields. No adjudication by specific medical experts for interpreting test results is described; rather, results are objectively compared against predefined numerical or qualitative criteria from the standards.
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Adjudication method (e.g., 2+1, 3+1, none) for the test set:
- "None" in the context of human expert adjudication as this was non-clinical engineering and materials testing against established standards. The review process for the submission at the FDA would involve regulatory experts assessing the manufacturer's presented data against requirements.
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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:
- No MRMC study was done. This document pertains to a Spinal Cord Stimulator, a medical device that delivers electrical impulses for pain relief, not an imaging or diagnostic AI device that would involve "human readers" or AI assistance in interpretation. The nature of this device does not fit the MRMC study paradigm.
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If a standalone (i.e. algorithm only without human-in-the loop performance) was done:
- This question is not applicable. The device is a physical medical implant system, not a standalone algorithm. Its performance is inherent to its design and function, not an AI algorithm.
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The type of ground truth used (expert consensus, pathology, outcomes data, etc):
- The "ground truth" for demonstrating substantial equivalence against legally marketed predicate devices primarily relies on:
- Standardized Test Methods and Acceptance Criteria: As set by numerous international and national standards (e.g., ISO 10993, AAMI ANSI ISO 14708-3, ASTM F2182-11a, IEC 60601-1) for biocompatibility, safety, and performance.
- Direct Comparison to Predicate Devices: Explicitly measuring and comparing physical and electrical parameters against established values of legally marketed devices (Table 5A).
- Design Requirements: Manufacturer-defined design specifications and requirements that the device must meet, often derived from industry best practices and safety considerations.
- There is no mention of pathology or outcomes data as "ground truth" for this specific 510(k) submission, as it focuses on non-clinical substantial equivalence.
- The "ground truth" for demonstrating substantial equivalence against legally marketed predicate devices primarily relies on:
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The sample size for the training set:
- This is not applicable. This is not an AI/ML device requiring a training set. The term "training set" is usually associated with machine learning models.
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How the ground truth for the training set was established:
- This is not applicable as there is no training set for this device.
§ 882.5880 Implanted spinal cord stimulator for pain relief.
(a)
Identification. An implanted spinal cord stimulator for pain relief is a device that is used to stimulate electrically a patient's spinal cord to relieve severe intractable pain. The stimulator consists of an implanted receiver with electrodes that are placed on the patient's spinal cord and an external transmitter for transmitting the stimulating pulses across the patient's skin to the implanted receiver.(b)
Classification. Class II (performance standards).