(90 days)
The Micrus Stretch-Resistant MicroCoil Delivery System is intended for endovascular embolization of intracranial aneurysms that – because of their morphology, their location or the patient's general medical condition -- are considered by the treating neurosurgical team to be a) very high risk for management by traditional operative techniques or b) inoperable.
The Micrus Stretch Resistant MicroCoil System consists of a platinum embolic coil ("MicroCoil") attached to a Device Positioning Unit (DPU) (single use, sterile). The Micrus Stretch Resistant MicroCoil System connects to a Micrus Connecting Cable (single use, sterile) which traverses the sterile field to connect to a Micrus Detachment Control Box (DCB) (reusable, non-sterile). The Connecting Cable and Detachment Control Box are sold separately. The Micrus Stretch-Resistant MicroCoils are available in a 10-System size, compatible with 10 and 14 sized microcatheters. They are helically shaped and are available in various diameters/dimensions. Coil lengths range from 1 to 15 centimeters and diameters range from 2 to 10 millimeters. The Stretch Resistant MicroCoils are available in two levels of softness: 1. The Micrus Soft, Stretch-Resistant MicroCoil (catalog # FSR) corresponds to the 10-System GDC Ultra Soft Stretch Resistant Coil, using a primary wind of 0.0015" to create softness. 2. The Standard Micrus Stretch-Resistant MicroCoil (catalog # HSR) corresponds to the 10-System GDC Soft, Stretch Resistant coil, using a primary wind of 0.00175". Micrus Stretch Resistant MicroCoils are fabricated from a platinum alloy wire, which is first wound into a primary coil (containing a non absorbable polypropylene suture inside the wind) and then formed into a secondary helical shape. The Micrus Stretch-Resistant MicroCoil System is identical to the FDAcleared MicroCoil System with the 4 following exceptions: 1. The coil's primary wind wire diameter has been reduced from 0.00175" to 0.0015" to create softness in the Micrus Soft Stretch-Resistant MicroCoil. (The Standard Micrus Stretch-Resistant MicroCoil uses the same 0.00175" diameter primary wind as is used in the Micrus 10-System Helical MicroCoil.) 2. A non absorbable polypropylene suture has been inserted inside the primary wind coil to create stretch-resistance. 3. The polypropylene suture is connected to the distal coil end to make a non-traumatic distal ball tip. 4. A loop of polypropylene suture has been added to the socket/ring connection at the coil to Device Positioning Unit junction to secure the polypropylene suture to the Device Positioning Unit.
The Micrus Stretch-Resistant MicroCoil System (MSR01) underwent several non-clinical tests to demonstrate its safety and effectiveness, and substantial equivalence to predicate devices (GDC Soft and Ultra Soft Stretch-Resistant). The study primarily focuses on bench testing and comparisons to established specifications of predicate devices rather than human clinical trials.
1. Table of Acceptance Criteria and Reported Device Performance
| Test/Characteristic | Acceptance Criteria (Characteristic) | Reported Device Performance (Test Data) |
|---|---|---|
| Aneurysm Packing Ability | Complete occlusion of aneurysms. | No filling defects evident on angio. |
| Detachment Reliability | No premature detachment / auto-detach caused by exposure to blood, body fluids, body temperatures, or repeated manipulation. 100% first detach-cycle detachment achieved. | 100% first detach-cycle detachment achieved. |
| Coil Stability & Aneurysm Occlusion | Positional stability and aneurysm occlusion maintained through 6 months of implant. No coil compaction. | Positional stability and aneurysm occlusion maintained through 6 months of implant. No coil compaction present at 6-month angio. |
| GDC Bench Marking | Established specifications for delivery force, tensile strength, and stiffness. The Micrus Stretch Resistant MicroCoil must be substantially equivalent to predicates. | Showed substantial equivalence in delivery force, tensile, and stiffness. |
| Coil Stiffness/Softness | Stiffness limit desired for Finishing Stretch Resistant MicroCoil. | Finishing Stretch Resistant MicroCoil and Helical Stretch Resistant MicroCoil stiffness is within desired stiffness limit. |
| Friction in the Microcatheter (Delivery Force) | Average push force must be substantially equivalent to predicates. | Finishing Stretch Resistant MicroCoil and Helical Stretch Resistant MicroCoil average push force exhibit comparable delivery forces. |
| MDR Database Review | MDR review for clinical risks. MSR01 risk assessment includes and addresses all risks encountered in review of predicate device MDR review. | MSR01 risk assessment includes and addresses all risks encountered in review of predicate device MDR review. |
| Biocompatibility of Materials | Meets the requirements of ISO 10993. The new material (polypropylene monofilament # 6523) must be identical to the pre-approved GDC stretch resistant suture. | The only new material in the Micrus Stretch Resistant MicroCoil is polypropylene monofilament # 6523. It is identical to the pre-approved GDC stretch resistant suture. |
| Sterilization Validation | Minimum Sterility Assurance Level of 10^-6^. | Passed minimum sterility assurance level of 10^-6^. |
| Shelf Life Test | No performance degradation after 1 year of shelf life aging. | Minimum tensile strength after 1 year accelerated aging shows no degradation. |
| Tensile Strength | Tensile strength of suture ball tip and MicroCoil to DPU must be substantially equivalent to predicates. | Tensile strength meets desired strength criteria. |
| Durability (Reliability after Fatigue) | Withstand deployment and retraction 6 times in a tortuous anatomy. No knotting, no breakage, no stretching. | No knotting, no breakage, no stretching occurred. Durability meets desired durability criteria. |
| MRI Compatibility of Implant | No change was made which would impact MRI compatibility. (Compared to predicate devices) | No change was made which would impact MRI compatibility (Therefore, assumed to be compatible based on predicate device compatibility, as mentioned in the "Technological Comparison" table under "Implantable Embolic Coil"). |
2. Sample Size Used for the Test Set and Data Provenance
The provided document describes non-clinical bench testing.
- Sample Size for Test Set: The exact sample sizes for each specific test (e.g., number of coils tested for detachment, number of "implants" for coil stability) are not explicitly stated in numerical terms (e.g., 100 coils, 20 coils). However, the narrative implies a sufficient quantity of samples were tested to generate the "Test data" against the "Characteristics" (acceptance criteria).
- Data Provenance: The data is from non-clinical bench tests performed on the "Micrus Stretch-Resistant Delivery System (MSR01)". This indicates the data was generated in a lab setting, likely within the manufacturing facility or a contracted testing facility, rather than from human patients. The document does not specify a country of origin beyond "Micrus Corporation" in Mountain View, California, USA. The data is prospective in the sense that the tests were conducted specifically for this submission to prove performance against established criteria.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
The concept of "ground truth established by experts" typically applies to clinical studies or image-based diagnostic systems. For these non-clinical, bench-level performance tests:
- Number of Experts: Not applicable in the context of establishing ground truth for these types of engineering and material performance tests.
- Qualifications of Experts: The "ground truth" (acceptance criteria) for these non-clinical tests is established based on engineering specifications, recognized industry standards (e.g., ISO 10993 for biocompatibility, sterility assurance levels), and the established performance characteristics of the predicate devices. These criteria would be developed and validated by engineers, quality control specialists, and regulatory affairs personnel with expertise in medical device design, manufacturing, and testing, rather than clinical experts like radiologists.
4. Adjudication Method for the Test Set
Adjudication methods (like 2+1, 3+1) are relevant for clinical studies, especially those involving human readers or subjective assessments. For these non-clinical bench tests:
- Adjudication Method: Not applicable. The results are typically quantitative measurements against objective criteria (e.g., "no filling defects," "100% first detach-cycle detachment," "within desired stiffness limit"). The determination of whether a test "passed" or "failed" is based on meeting these pre-defined, measurable criteria, not on expert consensus or adjudication of subjective interpretations.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
- MRMC Study: No, an MRMC comparative effectiveness study was not done. The document explicitly focuses on non-clinical tests and substantial equivalence to predicate devices based on technological characteristics and bench performance.
- Effect Size of Human Readers with/without AI: This information is not applicable as no MRMC study or AI component is mentioned.
6. Standalone (Algorithm Only) Performance Study
- Standalone Performance: No, a standalone algorithm performance study was not done. The device is a physical medical implant (microcoil system), not a software algorithm.
7. Type of Ground Truth Used
For the non-clinical tests described:
- Ground Truth: The "ground truth" is defined by engineering specifications, material science standards (e.g., ISO 10993, sterility standards), and established performance characteristics of the legally marketed predicate devices. For example, "complete occlusion of aneurysms" (as assessed in a simulated environment or animal model for aneurysm packing ability), "10^-6^ Sterility Assurance Level," and "delivery force, tensile strength, and stiffness" that are comparable to predicate devices. This is a form of objective, pre-defined technical and biological performance criteria.
8. Sample Size for the Training Set
- Training Set Sample Size: Not applicable. The device is a physical medical device, not a machine learning model, so there is no "training set" in the context of algorithm development.
9. How the Ground Truth for the Training Set Was Established
- Establishment of Ground Truth for Training Set: Not applicable, as there is no training set for this type of device.
§ 882.5950 Neurovascular embolization device.
(a)
Identification. A neurovascular embolization device is an intravascular implant intended to permanently occlude blood flow to cerebral aneurysms and cerebral ateriovenous malformations. This does not include cyanoacrylates and other embolic agents, which act by polymerization or precipitation. Embolization devices used in other vascular applications are also not included in this classification, see § 870.3300.(b)
Classification. Class II (special controls.) The special control for this device is the FDA guidance document entitled “Class II Special Controls Guidance Document: Vascular and Neurovascular Embolization Devices.” For availability of this guidance document, see § 882.1(e).