(26 days)
Catheter stylets provide internal reinforcement to aid in catheter placement. The Sherlock™ TLS Stylet contains passive magnets that generate a magnetic field. This field can be detected by the Sherlock™ TLS Detector to provide the placer rapid feedback on catheter tip location.
The Sherlock™ TLS Detector quickly locates and confirms the position of specially designed. magnet-tipped Peripherally Inserted Central Catheters (PICCS) and Central Venous Catheters (CVCs) during and after initial placement. This device may be used by appropriate caregivers in hospitals, long-term care facilities or home-care settings. The Sherlock™ TLS Detector provides rapid feedback to the caregiver, but was not designed to replace conventional methods of placement verification. Users are urged to confirm correct placement according to their established institutional protocol and clinical judgment.
The Sherlock™ Tip Location System (TLS) consists of the Sherlock™ TLS Detector and Sherlock™ TLS Stylet. The Sherlock™ TLS Stylet has been developed to aid in the placement of Bard Access Systems catheters using current placement techniques. The stylets are designed to give the catheters added support and stiffness while traversing the patient's venotomy. Also, should the clinician choose to do so, the stylets have been designed to be used in conjunction with Sherlock™ TLS Detector to allow for rapid feedback of catheter tip placement. The information provided by the Sherlock™ TLS is not meant to replace conventional methods of catheter placement verification. Clinicians are urged to confirm correct catheter placement according to their established institutional protocol and clinical judgment.
Here's an analysis of the provided text regarding the Sherlock™ (TLS) Stylet 510(k) Modifications:
1. Table of Acceptance Criteria and Reported Device Performance
The provided 510(k) summary does not explicitly list specific numerical acceptance criteria for performance metrics (e.g., accuracy, precision) for the Sherlock™ TLS Stylet. Instead, it states that:
- "The modified devices met the acceptance criteria for the tests performed."
- "Performance data demonstrated that the modified Sherlock™ TLS Stylets are substantially equivalent to the predicate devices and/ or met pre-determined acceptance criteria..."
- "The modified Sherlock™ TLS Stylets met predetermined performance acceptance criteria of testing performed..."
The type of tests performed focused on:
| Acceptance Criteria Type | Reported Device Performance |
|---|---|
| Safety - Risk Management (based on ISO 14971:2000) | A Failure Modes and Effects Analysis (FMEA) was conducted. "The analysis did not raise any new types of safety or effectiveness questions." Risks were found "acceptable." |
| Effectiveness - Design Validation | "The need for design validation was assessed and no additional validation was required." "The modification to the design did not necessitate the need for additional design validation activities." |
| Verification - Tensile Integrity | "Verification testing demonstrated the ability of the modified design to maintain tensile integrity under extreme kink conditions." (Specific numerical criteria for tensile strength or kink resistance are not provided). |
| Safety - Biocompatibility (ISO 10993-1 and FDA-Modified ISO 10993 Test Profile) | "Biocompatibility requirements... were met. No materials are used in the manufacture of the modified device that have not already been cleared for similar applications by Bard Access Systems." |
| Overall Performance / Substantial Equivalence (to predicate K060341) | Modified devices met predetermined acceptance criteria and demonstrated substantial equivalence to the predicate devices. The basic fundamental scientific technology of the stylet has not changed. |
2. Sample Size Used for the Test Set and Data Provenance
The document does not specify the sample size used for any of the verification or validation tests. It only states that "testing was performed according to protocols."
Regarding data provenance:
- The study was conducted by Bard Access Systems, Inc. in Salt Lake City, UT, USA.
- The nature of the testing described (tensile integrity, biocompatibility, FMEA) suggests that this was primarily prospective testing conducted on the modified Sherlock™ TLS Stylets themselves, rather than analysis of retrospective patient data.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
This information is not provided in the document. The tests described (tensile integrity, biocompatibility, FMEA) typically involve engineering and material science expertise, and risk assessment specialists, rather than clinical experts establishing a ground truth based on patient outcomes or imaging.
4. Adjudication Method for the Test Set
This information is not provided. Given the nature of the described tests, traditional clinical adjudication methods (like 2+1 reader adjudication) are not applicable. The FMEA would have involved expert review and consensus on potential risks and mitigations, but the specific adjudication process is not detailed.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done
No, a Multi-Reader Multi-Case (MRMC) comparative effectiveness study was not done or reported in this 510(k) summary. The document focuses on the technical verification and biocompatibility of the modified stylet and its substantial equivalence to a predicate device. It explicitly states that the Sherlock™ TLS system "was not designed to replace conventional methods of placement verification," and "Clinicians are urged to confirm correct catheter placement according to their established institutional protocol and clinical judgment." This suggests the device provides feedback but isn't intended as a standalone diagnostic or primary confirmation tool that would necessitate an MRMC study comparing human performance with and without its aid.
6. If a Standalone (i.e. algorithm only without human-in-the-loop performance) Was Done
Since the "Sherlock™ TLS Stylet" described here is a physical component (a stylet containing passive magnets) designed to be used with a "Sherlock™ TLS Detector" (the detector being the "algorithm" equivalent to provide feedback), a standalone test of only the stylet in isolation for diagnostic or performance metrics wouldn't be meaningful.
The "algorithm only" performance would reside in the Detector, which is part of the overall Sherlock™ TLS system. The summary implies the Detector provides "rapid feedback on catheter tip location," but its standalone diagnostic accuracy (without human interpretation or confirmation from conventional methods) is not quantified. The document emphasizes the system "was not designed to replace conventional methods of placement verification."
7. The Type of Ground Truth Used
The ground truth for the verification testing conducted on the stylet itself (e.g., tensile integrity) would be based on engineering specifications and quantifiable physical measurements. For biocompatibility, the ground truth would be established by validated biological assays and compliance with ISO 10993 standards.
For the intended function of detecting catheter tip location, the implicit ground truth for the overall Sherlock™ TLS system's function (not specifically detailed in this document for this modification, but likely part of the predicate's clearance K060341) would likely be conventional imaging methods (e.g., X-ray, fluoroscopy) used for catheter tip verification. However, this 510(k) is for modifications to the stylet, and confirms it maintains its characteristics relative to the predicate, rather than re-proving the entire system's accuracy against a clinical ground truth.
8. The Sample Size for the Training Set
This information is not applicable / not provided. The Sherlock™ TLS Stylet is a passive medical device containing magnets. It does not employ machine learning or artificial intelligence algorithms that require a "training set" in the conventional sense. The "detection" occurs in the Sherlock™ TLS Detector, but the stylet itself is a physical component.
9. How the Ground Truth for the Training Set Was Established
This information is not applicable / not provided for the same reasons as point 8.
§ 880.5970 Percutaneous, implanted, long-term intravascular catheter.
(a)
Identification. A percutaneous, implanted, long-term intravascular catheter is a device that consists of a slender tube and any necessary connecting fittings, such as luer hubs, and accessories that facilitate the placement of the device. The device allows for repeated access to the vascular system for long-term use of 30 days or more, and it is intended for administration of fluids, medications, and nutrients; the sampling of blood; and monitoring blood pressure and temperature. The device may be constructed of metal, rubber, plastic, composite materials, or any combination of these materials and may be of single or multiple lumen design.(b)
Classification. Class II (special controls) Guidance Document: “Guidance on Premarket Notification [510(k)] Submission for Short-Term and Long-Term Intravascular Catheters.”