(208 days)
The Phasix™ ST Mesh is indicated for use in the reinforcement of soft tissue, where weakness exists, in procedures involving soft tissue repair, such as for the repair of hernias, including hiatal hernias.
The Phasix™ ST Mesh is a fully resorbable mesh with a resorbable hydrogel coating. It is a sterile mesh prosthesis designed for the reinforcement and reconstruction of soft tissue deficiencies. Phasix ™ ST Mesh is co-knitted using poly-4-hydroxybuterate (P4HB) and polyglycolic acid (PGA) fibers. P4HB is produced from a naturally occurring monomer and is processed into monofilament fibers and then knitted into a surgical mesh. P4HB degrades through a process of hydrolysis and a hydrolytic enzymatic digestive process. It has been developed to reinforce areas where weakness exists while minimizing the variability of resorption rate (loss of mass) and strength to provide support throughout the expected healing period. Preclinical implantation studies indicate that resorption of the P4HB fibers is minimal throughout the 12 week expected healing period and up to 26 weeks post implantation. Significant degradation of the mesh fibers observed in preclinical studies within 12 to 18 months indicates loss in mechanical integrity and strength. While fiber segments were observed at 18 months, they continued to degrade. Phasix™ ST Mesh is coated on the PGA surface with a resorbable, chemically modified sodium hyaluronate (HA), carboxymethylcellulose (CMC) and polyethylene glycol (PEG) based hydrogel. The fascial side of the mesh allows for a prompt fibroblastic response through the interstices of the mesh, allowing for complete tissue ingrowth, similar to P4HB mesh alone. The visceral side of the mesh is a resorbable hydrogel coating, separating the mesh from underlying tissues and organ surfaces to help minimize tissue attachment to the mesh. Shortly after hydration, the biopolymer coating becomes a hydrated gel that is resorbed from the site in less than 30 days.
The provided text describes a 510(k) premarket notification for the "Phasix ST Mesh," a surgical mesh. The document details the device's description, indications for use, technological comparison to predicate devices, and performance data from various studies.
Here's an analysis of the requested information based on the provided text, categorized by the questions asked:
1. A table of acceptance criteria and the reported device performance
The document does not explicitly state formal "acceptance criteria" in a quantitative sense with specific thresholds. Instead, the performance data is presented as a demonstration that the device's characteristics are "comparable" to a predicate device or that differences "do not adversely affect safety and performance."
Therefore, I will interpret "acceptance criteria" as implied benchmarks for comparability to the predicate devices and summarize the reported performance in relation to these comparisons.
| Acceptance Criteria (Implied) | Reported Device Performance |
|---|---|
| Material & Design Equivalence to K143380 (Phasix ST Mesh) | The proposed Phasix™ ST Mesh is identical in material and design to the predicate Phasix™ ST Mesh (K143380) with the same intended use and similar indications for use. |
| Performance Comparability to Gore Bio-A Mesh (K033671) | Technological differences exist: different resorbable materials; minor differences in mesh thickness, density, ball burst strength, tear strength, and resorption profile. |
| Testing demonstrates that these differences do not adversely affect the safety and performance of the proposed device. | |
| Biocompatibility | Complete biocompatibility testing was performed in accordance with FDA's Blue Book Memorandum #G95-1 and FDA Guidance "Use of International Standard ISO-10993." Studies included: Cytotoxicity, Sensitization, Intracutaneous Reactivity, Systemic Toxicity (Acute), Pyrogenicity, Genotoxicity, Local and Systemic Toxicity (4 and 13 week), and Local Toxicity (4, 8, 13, and 20 week). (Results are implied to be acceptable as they support substantial equivalence). |
| Mechanical Strength & Tissue Response (Preclinical) | In vivo porcine studies characterized mechanical strength, tissue response, and resorption profile at 4, 12, and 24 weeks. Resorption of P4HB fibers was minimal up to 26 weeks, with significant degradation observed at 12-18 months, indicating loss of mechanical integrity. The hydrogel coating resorbed in less than 30 days. (Implied acceptable performance for intended healing period). |
| Physical & Performance Characteristics (Bench Testing) | Bench testing compared Phasix™ ST Mesh to Gore® Bio-A® for: Mesh thickness, Mesh density, Mesh pore size, Burst strength, Mesh knit/weave characteristics, Device stiffness, Tear strength/resistance, and Suture pullout strength. (Implied acceptable comparison results, demonstrating that minor technological differences do not adversely affect safety and performance). |
| Clinical Safety & Performance in Hiatal Hernia Repair | Study 1 (N=50): One small, asymptomatic recurrence. No mesh-related complications or erosions. |
| Study 2 (N=180): Two recurrent asymptomatic hernias (1-2 cm and 2-3 cm) not requiring reintervention. No mesh-related complications or mesh erosion. | |
| (Overall, these findings demonstrate safety and performance, specifically an absence of mesh-related complications and low, asymptomatic recurrence rates.) | |
| Electrical Safety & EMC | No electrical or metal components; therefore, not required for evaluation. |
| Software Verification & Validation | No software; therefore, not required for evaluation. |
2. Sample size used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective)
The document refers to two retrospective clinical studies. Combining them gives a total number of patients whose data was reviewed.
- Sample Size for the Test Set (Clinical Studies):
- Study 1: 50 patients
- Study 2: 180 patients
- Total: 230 patients
- Data Provenance:
- Both studies are explicitly stated as retrospective reviews.
- Both studies were conducted at a single institution. The country of origin is not explicitly stated, but the submission is to the U.S. FDA by a U.S. company (Davol Inc., Warwick, RI), making it highly probable the studies were conducted in the United States.
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)
The document does not provide details on the number or qualifications of experts used to establish ground truth for the clinical study data (e.g., for diagnosing recurrences or assessing complications). For retrospective reviews, the data is typically pulled from existing medical records, where diagnoses and assessments would have been made by the treating clinicians. The study design does not specify a separate "ground truth" adjudication panel.
4. Adjudication method (e.g. 2+1, 3+1, none) for the test set
The document does not describe any specific adjudication method (like 2+1 or 3+1 consensus) for the clinical study data. As indicated in point 3, the studies are retrospective reviews, implying that the outcomes (recurrences, complications) were determined based on existing clinical records by the treating physicians or the physicians performing the follow-up procedures (EGD, UGI, BS).
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
No, a multi-reader multi-case (MRMC) comparative effectiveness study was not done.
The Phasix ST Mesh is a physical surgical implant, not an AI software/device that assists human readers/clinicians in interpretation. Therefore, the concept of "human readers improve with AI vs without AI assistance" is not applicable to this device.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done
No, a standalone (algorithm-only) performance study was not done, as the device is a physical surgical mesh and not an algorithm or AI software.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc.)
For the clinical studies, the "ground truth" for assessing device safety and performance appears to be based on:
- Clinical outcomes data: This includes objective follow-up data (Esophagogastroduodenoscopy (EGD), Upper Gastrointestinal (UGI) series, Barium Swallow (BS)) and non-objective follow-up (unspecified clinical assessments).
- Medical records: The retrospective nature of the studies means that existing medical records were reviewed for reported complications, recurrences, and successful repairs.
For the animal studies, the "ground truth" involved histological and mechanical assessments conducted by researchers to characterize mechanical strength, tissue response, and resorption profile.
8. The sample size for the training set
This question is not applicable in the context of this device submission. The Phasix ST Mesh is a physical medical device (surgical mesh), not an AI algorithm or a device that requires a "training set" in the machine learning sense. The performance data consists of biocompatibility testing, animal studies, bench testing, and retrospective clinical reviews, none of which utilize a "training set."
9. How the ground truth for the training set was established
As in point 8, this question is not applicable because there is no "training set" for this physical medical device.
§ 878.3300 Surgical mesh.
(a)
Identification. Surgical mesh is a metallic or polymeric screen intended to be implanted to reinforce soft tissue or bone where weakness exists. Examples of surgical mesh are metallic and polymeric mesh for hernia repair, and acetabular and cement restrictor mesh used during orthopedic surgery.(b)
Classification. Class II.