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The truFreeze is indicated for use as a cryosurgical tool in the fields of dermatology, gynecology, and general surgery, to ablate benign and malignant lesions.

Device Description

The truFreeze system is a cryosurgical tool that applies medical-grade liquid nitrogen to the treatment area via a small, low pressure, open tipped catheter. The truFreeze System consists of (1) a console and (2) 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 wireless remote control provides alternative timer control from a distance in the treatment room. 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:
The truFreeze disposable spray kit consists of 5 individually packaged sterile single-use catheters ( 7 Fr Straight Tip Catheter and one Catheter Introducer.) and 5 individually packaged cryogen decompression tubes (CDTs) (each containing one Dual Lumen 20 Fr CryoDecompression Tube (CDT), Connector, and Suction Tubing.). The catheter is flexible and capable of retroflex in a scope. The CDT and accessory tubes are included for use with the on-board suction system.

AI/ML Overview

Here's an analysis of the acceptance criteria and study information for the truFreeze® System based on the provided document:

1. Table of Acceptance Criteria and Reported Device Performance

Bench Test Characteristic	Acceptance Criteria (Predicate IceSense3 K102360)	Reported Device Performance (Proposed truFreeze® System K133258)	Comments from Study
Ability to reach equivalent dose (using same freeze/thaw/freeze cycle)	2min/2min/2min = 2.1-2.5cm depth	2min/2min/2min = 1.8-2.4cm depth	Both capable of producing equivalent depth of ice
	3min/2min/3min = 2.6-3.0cm depth	3min/2min/3min = 2.4-3.0cm depth
	4min/4min/4min = 3.1-4.0cm depth	4min/4min/4min = 3.0-3.6cm depth
Output Temperature at tip	-170 degree C	-196 degree C	Both achieve temperatures low enough to destroy malignant tissue
Equivalent temperature distribution using the radial distance from the 0°C isotherm (border of ice ball) to the -20°C, -40°C and -50°C isotherms	@ freeze depth of 22mm at 0°C:
-20°C isotherm at 16.9mm depth
-40°C isotherm at 13.4mm depth	@ freeze depth of 21.87mm at 0°C:
-20°C isotherm at 15.5mm depth
-40°C isotherm at 11.8mm depth	Both can produce lethal ice at comparable depths

2. Sample Size Used for the Test Set and Data Provenance

The document explicitly states that "limited bench testing was conducted to support demonstration of substantial equivalence." It does not specify the sample sizes (e.g., number of tests, number of trials) for each bench test performed. Given the nature of bench testing, the data provenance would be laboratory-controlled (not patient data). The document refers to the data as "bench testing," implying a prospective experimental setup in a lab environment. The country of origin of the data is not mentioned but can be inferred as the USA, as the applicant is CSA Medical in Lexington, MA.

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. Bench testing typically does not involve human experts establishing ground truth in the same way clinical studies do. The "ground truth" for these tests would be the physical measurements taken (e.g., ice ball dimensions, temperature readings) by the testing equipment and personnel.

4. Adjudication Method for the Test Set

This information is not applicable and therefore not provided. Bench testing focuses on objective physical measurements, not subjective evaluations that would require adjudication among experts.

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

An MRMC comparative effectiveness study was not conducted. The document describes bench testing to demonstrate substantial equivalence to a predicate device, not a study involving human readers or AI assistance.

6. If a Standalone (i.e. algorithm only without human-in-the-loop performance) was done

A standalone performance study of an algorithm was not done. The "device" in this context is a cryosurgical tool (hardware with integrated software), not an AI algorithm. The performance evaluation was of the physical device's capabilities (ice ball formation, temperature output) in a lab setting.

7. The Type of Ground Truth Used

For the bench testing, the ground truth was based on physical measurements of:

Ice ball depth (in cm) under different freeze/thaw/freeze cycles.
Output temperature at the catheter tip (in degrees C).
Radial distance of specific isotherms (-20°C, -40°C) from the 0°C isotherm at a given freeze depth.

These are objective, quantitative measurements taken directly from the device's operation.

8. The Sample Size for the Training Set

This information is not applicable and therefore not provided. The truFreeze® System is a physical cryosurgical device, not a machine learning model that requires a training set of data.

9. How the Ground Truth for the Training Set Was Established

This information is not applicable for the same reason as above (no training set for a physical device).

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