(252 days)
The C2 CryoBalloon™ Ablation System is intended for use as a cryosurgical tool in the field of general surgery, specifically for endoscopic applications, to include ablation of Barrett's Esophagus with dysplasia.
The subject device is a cryosurgical system with a nitrous oxide cooled balloon that is compatible with a commercially available endoscope with a minimum working channel inner diameter (ID) of 3.7 mm and length of 100 cm. The subject device is a system comprised of a Catheter (sterile), Controller (non-sterile), and Cartridge (nonsterile). The subject device is used to ablate unwanted tissue by application of extreme cold to a 360° circumference. 90° circumference. or 45° circumference and is identical to the respective predicates. The balloon at the distal end of the Catheter comes in contact with tissue and is inflated with nitrous oxide. Tissue is visualized through the preinflated balloon, and the treatment site is selected by adjusting the endoscope and Controller position. The nitrous oxide spray cools the balloon to ablate the unwanted tissue, and the nitrous oxide exhausts through the Controller.
Here's an analysis of the acceptance criteria and study detailed in the provided document:
Acceptance Criteria and Device Performance for C2 CryoBalloon™ Ablation System
1. Table of Acceptance Criteria and Reported Device Performance
The document focuses on demonstrating substantial equivalence by comparing the subject device's performance to existing predicate devices and other ablation technologies for Barrett's Esophagus with Low-Grade Dysplasia (LGD). While explicit, quantified "acceptance criteria" for the device are not directly stated as distinct thresholds, the document presents reported performance metrics from clinical studies and implicitly aims to show these metrics are "within the same range" as other accepted treatments. Based on the provided text, the key performance metrics and their reported values are:
| Performance Metric | Acceptance Criteria (Implicit from comparator devices/literature) | Reported Device Performance (C2 CryoBalloon, combined from Schölvinck 2015 & Canto 2016 for LGD) |
|---|---|---|
| Efficacy Rate (Resolution of LGD) | RFA: 90% at 12-month follow-up (Shaheen et al.), 93% at 36-month follow-up (Phoa et al.) | |
| CSA Spray Cryotherapy: 91% at 21-month follow-up (Ghorbani et al.) | 92% (5/5 and 12/13 patients, 100% and 92% resolution respectively, combined for LGD patients) | |
| Serious Adverse Event (SAE) Rate | RFA: 2.4% (Shaheen et al.), 4.4% (Phoa et al.) | 4.5% (1/22 LGD patients) |
| Breakdown of SAEs (for LGD patients) | (Implicitly low or comparable to RFA) | Dysphagia: 0% |
| Stricture: 8% (1/13, in Canto 2016, pre-existing history) | ||
| Bleeding: 0% | ||
| Perforation: 0% | ||
| Pain requiring prolonged narcotics: 0% | ||
| Breakdown of Non-Serious Adverse Events (Non-SAEs) | (Implicitly low or comparable to RFA) | Dysphagia ≥ 24 hours: 15% (2/13, in Canto 2016) |
| Stricture: 0% | ||
| Mucosal laceration: 22% (2/9, in Schölvinck 2015) | ||
| Pain requiring narcotics ≥ 24 hours: 8% (1/13, in Canto 2016) |
Rationale for "Acceptance Criteria" interpretation: The document states that "The LGD efficacy rate of 92% and SAE rate of 5% (1/22) for the subject device are within the same range as the safety and efficacy rates for the RFA ablation and other cryoablation devices reported in the literature." This implies that the performance of similar, already cleared devices serves as a de facto acceptance standard for substantial equivalence.
2. Sample Sizes Used for the Test Set and Data Provenance
The "test set" for demonstrating the efficacy and safety for Barrett's Esophagus with LGD comes from two prospective clinical studies:
- Schölvinck 2015:
- Sample Size (LGD patients): 9 patients (out of 39 total patients in the study)
- Data Provenance: Not explicitly stated, but it's a published scientific paper, likely international given the author names (e.g., Künzli, Siersema, Vleggaar, Bergman, Weusten often associated with European institutions). The study description implies it's prospective ("safety and feasibility study").
- Canto 2016:
- Sample Size (LGD patients): 13 patients (out of 40 total patients in the study)
- Data Provenance: Not explicitly stated but the title and authors (Canto, Lightdale, Cosby, Montgomery) suggest a U.S. context, potentially a multi-center study ("Preliminary Results of a Prospective Clinical Trial"). Described as prospective.
Combined Test Set for LGD: 22 patients (9 from Schölvinck 2015 + 13 from Canto 2016).
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of those Experts
The document does not specify the number of experts explicitly used to establish the ground truth for the test set (i.e., for determining resolution of LGD or presence of adverse events). However, it mentions pathologically confirmed BE, indicating that pathologists were involved in the diagnosis and assessment of dysplasia. The qualifications of these pathologists are not detailed.
4. Adjudication Method for the Test Set
The document does not explicitly describe an adjudication method (like 2+1, 3+1 consensus) for the test set results (e.g., for determining resolution of LGD or categorizing adverse events). The assessment of LGD resolution was "determined with biopsy," implying a standard pathological review. Adverse events would typically be assessed by the treating clinicians and reported according to study protocols.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was done, and its effect size.
No, a Multi-Reader Multi-Case (MRMC) comparative effectiveness study was not done. The studies presented are clinical trials evaluating the safety and efficacy of the device in patients, not comparing reader performance with and without AI assistance. The device itself is a treatment device, not an AI-assisted diagnostic tool.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) was done
This refers to the performance of a diagnostic algorithm without human interaction. This is not applicable here as the C2 CryoBalloon™ Ablation System is a cryosurgical treatment device, not a diagnostic algorithm.
7. The Type of Ground Truth Used
For the clinical studies (Schölvinck 2015 and Canto 2016):
- For Dysplasia Diagnosis and Resolution: Pathology (biopsy results) was used for "Pathologically confirmed BE" and for determining "residual LGD as determined with biopsy."
- For Adverse Events: Clinical assessment and follow-up data from the prospective studies, likely involving physician diagnosis and classification of events, along with any necessary objective findings.
For the preclinical study (Schölvinck 2014):
- For Histopathological Effects: Pathology (histopathology from swine models and human biopsies) was used.
8. The Sample Size for the Training Set
The document does not describe a "training set" in the context of an AI/ML algorithm. This device is a cryosurgical system, and its efficacy and safety are demonstrated through preclinical and clinical studies, not through machine learning model training.
9. How the Ground Truth for the Training Set was Established
As there is no "training set" for an AI/ML algorithm described in the context of this device, this question is not applicable. The device's design and mechanism are based on established scientific principles of cryoablation, and its performance is validated through traditional biological and clinical studies.
§ 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.