(50 days)
Intended Use: The truFreeze System is intended for cryogenic destruction of tissue using Liquid Nitrogen spray that has a boiling point of -196ºC requiring either active or passive venting during surgical procedures.
Indications for Use: The truFreeze System is indicated for use as a cryosurgical tool in the fields of dermatology, and general surgery, to ablate benign and malignant lesions.
The truFreeze system is a cryosurgical tool that applies medical-grade liquid nitrogen to the ablation area via a small, low pressure, open tipped catheter. The truFreeze System consists of a console and a disposable spray kit.
Console: The console is the central interface of the system and is comprised of a touch panel computer (TPC) and cryogen, suction, and electronics modules packaged in a mobile cart. Users interact with the console through a dual foot pedal and a touch panel. An off-the-shelf controller and associated software manage the cryogen level sensing, filling, pressure, cooling, defrost, suction, timing and data management functions. A fill kit, stored on the rear of the console, allows for liquid nitrogen transfer from the source tank to the console. Safety features include indicators, tank pressure relief valves, an isolated low voltage power system, and an emergency button to be used in the event of user or technical malfunction.
Disposable spray kit: There are 2 types of spray kits available. One kit is available for active venting procedures and one is available for passive venting procedures. Both active and passive venting kits include are provided in a carton of five (5) individually packaged sterile, single-use catheters with introducers in individual pouches. Additionally, the active venting kit is provided with includes a carton of five (5) individually packaged sterile, single-use CDTs with associated tubing in individual pouches. Each carton within a spray kit contains the instructions for use.
This document describes a 510(k) premarket notification for the truFreeze® System (K161557), which is a cryosurgical unit. The submission focuses on modifications to the predicate device (K160273) and assesses if these changes introduce new questions of safety or effectiveness. The core of the evaluation is demonstrating that the modified device remains substantially equivalent to its predicate.
Here's an analysis of the provided information regarding acceptance criteria and the study that proves the device meets them:
1. A table of acceptance criteria and the reported device performance:
The document doesn't explicitly state "acceptance criteria" in a quantitative manner for specific performance metrics like accuracy, sensitivity, or specificity. Instead, the acceptance criteria are implicitly defined as successful completion of various verification and validation tests, ensuring that the software and hardware modifications do not negatively impact the code, system performance, or functionality, and do not raise new questions of safety or effectiveness.
The "Verification Testing Summary Table" provides a good overview of the tests performed and their outcomes:
| Test Type | Proposed truFreeze System Performance | Predicate truFreeze System (K150920) Performance | Comments |
|---|---|---|---|
| Software Regression Tests | |||
| - BIT Code | Pass | Pass | Equivalent |
| - Fill Code | Pass | Pass | Equivalent |
| - Procedure Code | Pass | Pass | Equivalent |
| - Data Code | Pass | Pass | Equivalent |
| - Service Code | Pass | Pass | Equivalent |
| - Admin Code | Pass | Pass | Equivalent |
| - Home Code | Pass | Pass | Equivalent |
| Software Integration Tests | |||
| - Fill Code | Pass | NA | The integration tests were specific to the proposed modifications and therefore it was not part of K150920 |
| - Procedure Code | Pass | NA | The integration tests were specific to the proposed modifications and therefore it was not part of K150920 |
| System Functional Tests | |||
| - truFreeze Field Verification | Pass | Pass | Equivalent |
| Hardware Stress Tests | |||
| - Simulated Shock and Rotation | Pass | NA | The simulated shock and rotation methods were not part of K150920 testing. |
Reported Device Performance Summary: All tests, including software regression, software integration, system functional, and hardware stress tests, were successfully completed with a "Pass" result for the proposed truFreeze System, demonstrating that the modifications did not negatively affect the device's safety or functionality.
2. Sample size used for the test set and the data provenance (e.g., country of origin of the data, retrospective or prospective):
- Software Testing:
- Regression Tests: The document states that "Regression testing was successfully completed and all tests passed," implying 100% pass rate for the tested code components (BIT, Fill, Procedure, Data, Service, Admin, Home Codes). The exact number of individual test cases within these categories is not specified.
- Integration Tests: "All integration tests were completed and were considered acceptable." Again, the specific number of test cases or scenarios is not provided.
- Unit Tests: "Unittests were used to verify the BIT and code revision updates... only one run on one console is required for this testing." This indicates a single run for these specific unit tests.
- Hardware and System Functional Testing:
- Hardware Stress Testing: "Three production equivalent systems underwent stress testing."
- System Functional Tests: "System functional testing was performed on three production consoles."
- Data Provenance: The testing appears to be internal to CSA Medical, Inc. or its contractors. No information is provided about the country of origin of data, or whether it was retrospective or prospective in the sense of patient data. This is a simulated/laboratory testing environment, not clinical data provenance.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts (e.g., radiologist with 10 years of experience):
This type of information is not applicable to the testing described in this document. The truFreeze® System is a cryosurgical tool, and the testing outlined is focused on verifying software and hardware functionality and safety of modifications, not diagnostic accuracy requiring expert panel review. The "ground truth" for these tests would be the expected behavior of the system as defined by its design specifications.
4. Adjudication method (e.g., 2+1, 3+1, none) for the test set:
This is not applicable as the testing primarily involves automated software verification, hardware stress tests, and functional checks against predetermined specifications, not subjective interpretation of results by multiple human adjudicators. The evaluation outcome (Pass/Fail) is based on objective criteria related to system performance and behavior.
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:
This is not applicable. The truFreeze® System is a physical medical device (cryosurgical unit) and its modifications are for internal system functionality, not an AI-powered diagnostic or assistive tool for human readers (e.g., radiologists interpreting images). Therefore, an MRMC study or assessment of AI assistance effect size is irrelevant here.
6. If a standalone (i.e., algorithm only without human-in-the-loop performance) was done:
This is not applicable in the context of an "algorithm only" performance as it relates to AI/diagnostic algorithms. The device itself is a standalone system with specific functionalities, and the testing implicitly evaluates its standalone performance relative to its design specifications. However, this is not a device whose performance would be measured in terms of classification, detection, etc., like an AI algorithm.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc.):
The "ground truth" for the tests described is the expected behavior and performance of the device's software and hardware as defined by its design specifications and requirements. For example:
- For software regression, the ground truth is that the updated code should produce the same correct output as the previous version for existing functionalities.
- For integration tests, the ground truth is that the software should correctly detect errors and display messages as designed.
- For hardware stress tests, the ground truth is that the hardware modifications should withstand simulated stress without failure.
8. The sample size for the training set:
This is not applicable. The document describes verification and validation of modifications to a physical medical device and its embedded software, not the development or training of a machine learning or AI model. Therefore, there is no "training set" in this context.
9. How the ground truth for the training set was established:
This is not applicable as there is no training set for an AI model. The ground truth for the testing was established through design specifications and requirements for the device's intended functionality and safety.
§ 878.4350 Cryosurgical unit and accessories.
(a)
Identification —(1)Cryosurgical unit with a liquid nitrogen cooled cryoprobe and accessories. A cryosurgical unit with a liquid nitrogen cooled cryoprobe and accessories is a device intended to destroy tissue during surgical procedures by applying extreme cold.(2)
Cryosurgical unit with a nitrous oxide cooled cryoprobe and accessories. A cryosurgical unit with a nitrous oxide cooled cryoprobe and accessories is a device intended to destroy tissue during surgical procedures, including urological applications, by applying extreme cold.(3)
Cryosurgical unit with a carbon dioxide cooled cryoprobe or a carbon dioxide dry ice applicator and accessories. A cryosurgical unit with a carbon dioxide cooled cryoprobe or a carbon dioxide dry ice applicator and accessories is a device intended to destroy tissue during surgical procedures by applying extreme cold. The device is intended to treat disease conditions such as tumors, skin cancers, acne scars, or hemangiomas (benign tumors consisting of newly formed blood vessels) and various benign or malignant gynecological conditions affecting vulvar, vaginal, or cervical tissue. The device is not intended for urological applications.(b)
Classification. Class II.