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The Polyaxial Hemispherical Spinal Screws are intended for posterior, noncervical pedicle and non-pedicle fixation for the following indications: degenerative disc disease(DDD) (defined as back pain of discogenic origin with degeneration of the disc confirmed by history and radiographic studies); spondylolisthesis; trauma (i.e., fracture or dislocation); spinal stenosis; curvatures (i.e., scoliosis, and/or lordosis); tumor; pseudoarthrosis; and failed previous fusion.

As a pedicle screw system the Polyaxial Hemispherical Spinal Screws are intended for the treatment of severe spondylolisthesis (Grade 3 and 4) of the L5-S1 vertebrae in skeletally mature patients receiving fusion by autogenous bone graft having implants attached to the lumbar and sacral spine (L3 to sacrum) with removal of the implants after the attainment of a solid fusion.

The ISOBAR Spinal System consists of monoaxial and polyaxial pedicle screws rods, nuts and cross link members. (K990118, K013447 and K031290) It can be used for single or multiple level fixation. It also includes single and double hooks (K013444 and K013440) used for posterior, nonpedicle screw fixation of the noncervical spine, hook and sacral/iliac screw fixation to the noncervical spine and hook and sacral screw fixation to the T1-S1 spine.

The modification included in this submission is the addition of polyaxial hemispherical screws. These screws function in the same manner as the previously cleared hemispherical screws by insertion into the pedicle then placing an offset clamp over the screw with a rod that has been loaded into the clamp. A nut is them placed on the screw and tightened to secure the assembly. The new polyaxial screw allows the proximal portion of the screw to angulate in order to ease the assembly of the rod loaded clamps onto multiple screws that may not be axially aligned.

Here's an analysis of the provided text regarding the acceptance criteria and study for the Polyaxial Hemispherical Spinal Screws:

1. Table of Acceptance Criteria and Reported Device Performance

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

The provided summary does not explicitly state a sample size for the test set. It mentions "Testing was performed per ATM F1717," which is a standard for pedicle screw spinal systems. This implies that the tests outlined in ASTM F1717 would have been conducted on a sufficient number of devices to demonstrate equivalence.

The data provenance is commercial, with the submitter being Scient'x, located in France. The testing would have been conducted by the manufacturer or a contracted lab in support of U.S. market clearance. The submission is retrospective in the sense that the testing was performed before the 510(k) submission.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts

This information is not applicable to this type of device submission. For a mechanical device like a spinal screw, the "ground truth" is established by adherence to a recognized international standard (ASTM F1717) and the physical properties of the materials and design, not by expert interpretation of data like in medical imaging.

4. Adjudication Method for the Test Set

This is not applicable to this type of mechanical testing. Adjudication methods like 2+1 or 3+1 are used for expert review of subjective data (e.g., medical images). The results of ASTM F1717 are objective measurements.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done

No, an MRMC comparative effectiveness study was not done. This type of study is relevant for evaluating the performance of diagnostic or screening devices, particularly those involving human interpretation of data, and how an AI system might improve that human performance. This is a mechanical implant device.

6. If a Standalone (Algorithm Only Without Human-in-the-Loop Performance) Was Done

This question is not applicable as this is a mechanical spinal implant, not an AI algorithm.

7. The Type of Ground Truth Used

The "ground truth" for the performance of the Polyaxial Hemispherical Spinal Screws relies on engineering specifications and recognized international standards (ASTM F1717). The comparison is made against the performance of a previously cleared predicate device that presumably also met these standards.

8. The Sample Size for the Training Set

This question is not applicable. This is a mechanical device, not an AI/ML algorithm that requires a training set.

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

This question is not applicable. As explained above, there is no "training set" for this type of device.

Summary of the Study:

The "study" or rather, the non-clinical testing, performed to demonstrate the device meets acceptance criteria was based on ASTM F1717, a standard specification for spinal pedicle screw systems. The crucial aspect of the study was to show that the modified device (Polyaxial Hemispherical Spinal Screws) performed comparably to its predicate device (Scient'x ISOBAR Hemispherical Screw system). The specific performance metrics would have included various mechanical tests such as static and dynamic compression bending, torsion, axial pullout, implant-to-implant connection strength, corrosion resistance, and fatigue strength, as described in ASTM F1717. The acceptance criteria essentially were to meet or exceed the performance characteristics of the predicate device under these standardized conditions. The FDA's clearance (K051063) indicates that the agency found the results of this testing sufficient to establish substantial equivalence.

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