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The Wenzel Spine VariLift Cervical Interbody Fusion System is indicated for use in skeletally mature patients with degenerative disc disease (DDD) of the cervical spine with accompanying radicular symptoms at one disc level. DDD is defined as discogenic pain with degeneration of the disc confirmed by patient history and radiographic studies. These DDD patients may have up to Grade 1 spondylolisthesis or retrolisthesis at the involved level(s).

The Wenzel Spine VariLift Cervical Interbody Fusion System is used to facilitate intervertebral body fusion in the cervical spine and is placed in a unilateral or a bilateral fashion via an anterior approach at the C3 to C7 disc levels using autograft bone. The Wenzel Spine VariLift Cervical Interbody Fusion System is to be used with supplemental fixation. Patients should have at least six (6) weeks of non-operative treatment prior to treatment with an intervertebral fusion device.

The Wenzel Spine VariLift Cervical Interbody Fusion System is self-tapping, expandable devices with an interior sliding wedge. The devices are cylindrical-ovoid in shape, which is adapted to the general shape of the vertebral end plates. All components are composed of Titanium-6AI-4V ELI alloy that conforms to ASTM F136.

The VariLift Cervical device is grooved and fluted with large fenestrations (graft windows) positioned between each of its four quadrants that provide bony contact with the endplates.

The device is supplied in an appropriately labeled sterile packaging.

The instrument case is 10 inch X 20 inch. All instruments for VariLift-C fit on a single tray.

The provided text describes the Wenzel Spine VariLift Cervical Interbody Fusion System, which is a medical device. It does not describe a device that uses AI or machine learning, nor does it present any studies involving acceptance criteria or comparative effectiveness in the way an AI/ML device submission would.

Therefore, for each of your requested points, the answer is that the information is not applicable or not provided in the given summary because the device is a physical interbody fusion system, not an AI/ML diagnostic or assistive tool.

Here's a breakdown based on your request, directly addressing why the information isn't present:

1. A table of acceptance criteria and the reported device performance

• Not Applicable / Not Provided: The document focuses on demonstrating substantial equivalence to predicate devices through design, material, and non-clinical mechanical testing. It does not define acceptance criteria in terms of performance metrics (like accuracy, sensitivity, specificity) that would be relevant for an AI/ML device. The "performance" is demonstrated by meeting mechanical testing standards (ASTM F2077-03) and claiming substantial equivalence to existing devices.

2. Sample size used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective)

• Not Applicable / Not Provided: This question is relevant for AI/ML validation datasets. For a physical medical device like the VariLift, "test set" would refer to the samples used in mechanical testing. The document states "Static and dynamic compression testing," "Static shear testing," "Static and dynamic torsion testing," and "Expulsion testing" were conducted in accordance with ASTM standards, but it does not specify the sample sizes (number of devices tested) for these non-clinical tests or any "data provenance" as that term is used in AI/ML.

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)

• Not Applicable / Not Provided: "Ground truth" established by experts is a concept for AI/ML performance evaluation where human judgment is the reference. For this physical device, the "ground truth" for mechanical testing is defined by the ASTM standards (e.g., maximum load before failure, displacement at a certain load). No human experts are used to establish "ground truth" in this context.

4. Adjudication method (e.g. 2+1, 3+1, none) for the test set

• Not Applicable / Not Provided: Adjudication methods like 2+1 or 3+1 are used in AI/ML studies when multiple human readers independently review cases and then resolve disagreements to establish a consensus ground truth. This is not relevant for the mechanical testing of a physical implant.

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

• Not Applicable / Not Provided: An MRMC study is designed to evaluate the impact of an AI tool on human reader performance. Since the VariLift is a physical interbody fusion system and not an AI-powered tool, such a study would not be performed for this device.

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

• Not Applicable / Not Provided: This question pertains to the performance of an AI algorithm on its own. The VariLift is a physical device, so there is no "algorithm only" performance to evaluate.

7. The type of ground truth used (expert consensus, pathology, outcomes data, etc.)

• Not Applicable / Not Provided: As in point 3, the concept of "ground truth" as a reference for diagnostic accuracy is not directly applicable. For non-clinical mechanical testing, the "truth" is whether the device meets predefined physical performance specifications according to standardized test methods (like ASTM F2077-03).

8. The sample size for the training set

• Not Applicable / Not Provided: A "training set" is used to develop or train an AI/ML model. This device is a physical implant, not an AI/ML model, so there is no training set involved.

9. How the ground truth for the training set was established

• Not Applicable / Not Provided: Since there is no training set for an AI/ML model, the establishment of ground truth for such a set is irrelevant for this medical device submission.

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