(143 days)
The Libra Pedicle Screw System is intended for immobilization of the posterior thoracic, lumbar and sacral/iliac spine (TI-S1/Ilium) in skeletally mature patients as an adjunct to the following indications: degenerative disc disease (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, kyphosis, or lordosis), tumor, pseudarthrosis, and/or failed previous fusion.
The Libra Pedicle Screw System consists of longitudinal members (rods), anchors (screws) and fasteners in a variety of sizes to accommodate differing anatomic requirements.
This document describes the FDA's clearance of the Libra Pedicle Screw System (K151770) based on substantial equivalence to predicate devices, rather than a study and acceptance criteria for a novel device's performance. Therefore, the requested information about device performance, sample sizes, ground truth establishment, expert adjudication, and MRMC studies is not directly available in this text.
However, I can extract information related to the performance data provided for substantial equivalence and the acceptance criteria implicitly met through comparison with predicates.
Implicit Acceptance Criteria and Reported Device Performance (Table)
| Acceptance Criteria (Implied) | Reported Device Performance |
|---|---|
| Mechanical Performance: | |
| Static Compression Bending (as per ASTM F1717) | The mechanical test results demonstrate that Libra Pedicle Screw System performance is substantially equivalent to the predicate devices. (Specifically, static compression bending was performed according to ASTM F1717). |
| Dynamic Compression Bending (as per ASTM F1717) | The mechanical test results demonstrate that Libra Pedicle Screw System performance is substantially equivalent to the predicate devices. (Specifically, dynamic compression bending was performed according to ASTM F1717). |
| Static Torsion (as per ASTM F1717) | The mechanical test results demonstrate that Libra Pedicle Screw System performance is substantially equivalent to the predicate devices. (Specifically, static torsion was performed according to ASTM F1717). |
| Biocompatibility: | Not explicitly detailed in the provided text, but implied to be acceptable as part of regulatory requirements for Class III devices, likely based on material (Ti-6Al-4V ELI titanium alloy (ASTM F136)) and comparison to predicate devices utilizing similar materials. |
| Sterilization: | Not explicitly detailed in the provided text, but implied to be acceptable as part of regulatory requirements for Class III devices. |
| Design Characteristics: | The Libra Pedicle Screw System possesses the same technological characteristics as one or more of the predicate devices. These include: intended use, basic design (rod and screw configuration), material (titanium alloy), and sizes (dimensions are comparable to those offered by the predicate systems). The fundamental scientific technology is the same as previously cleared devices. |
| Intended Use & Indications: (Substantially Equivalent to Predicates) | The Libra Pedicle Screw System is intended for immobilization and stabilization of the posterior thoracic, lumbar and sacral/iliac spine (T1-S1/Ilium) in skeletally mature patients as an adjunct to fusion for indications like degenerative disc disease, spondylolisthesis, trauma, spinal stenosis, curvatures, tumor, pseudarthrosis, and/or failed previous fusion. |
Since this is a 510(k) summary for a substantial equivalence determination for a medical device (pedicle screw system), the "study" is primarily focused on bench testing to demonstrate that the new device performs as safely and effectively as legally marketed predicate devices, not clinical studies with human performance metrics as one might see for AI/software devices. Therefore, many of your specific questions are not directly applicable or answerable from this document.
Here's an attempt to address your other points based on the provided text, acknowledging the nature of a 510(k) submission for a physical implantable device:
2. Sample size used for the test set and the data provenance
- Test Set Sample Size: The document does not specify the exact number of Libra Pedicle Screw System constructs tested for mechanical performance. It generally refers to "worst case Libra Pedicle Screw System constructs." For a 510(k) for a physical device, this typically involves a representative number of samples (e.g., typically 3 to 5 per test condition) to satisfy the standard (ASTM F1717). The specific number is usually detailed in the full 510(k) submission, not summarized at this level.
- Data Provenance: The data is from bench testing (mechanical testing), conducted by the manufacturer, Spinal Balance Inc., to evaluate the physical components of the device. It is not clinical data, and thus concepts like "country of origin of the data" or "retrospective/prospective" do not apply in the same way they would for clinical or AI data.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts
- Not applicable in this context. For mechanical bench testing, "ground truth" is established by the specifications and pass/fail criteria of the referenced ASTM standards (ASTM F1717). Engineers and technicians conduct the tests and determine if the results meet the criteria, comparing them against the performance of similar predicate devices. There isn't "expert adjudication" of test results in the sense of clinical image review for diagnostic accuracy.
4. Adjudication method for the test set
- Not applicable. See point 3. Testing against an industry standard (ASTM F1717) provides objective pass/fail criteria.
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. This device is a physical spinal implant, not an AI software. Therefore, MRMC studies and the concept of "human readers improving with AI assistance" are irrelevant to this submission.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done
- Not applicable. This is a physical medical device, not an algorithm.
7. The type of ground truth used
- For mechanical testing, the "ground truth" is adherence to the performance standards and specifications outlined in ASTM F1717, and the comparative performance to predicate devices as demonstrated by their own cleared mechanical testing data. The goal is to show equivalent, safe, and effective mechanical properties.
8. The sample size for the training set
- Not applicable. This is a physical medical device, not a machine learning model, so there is no training set in the AI sense.
9. How the ground truth for the training set was established
- Not applicable. See point 8.
§ 888.3070 Thoracolumbosacral pedicle screw system.
(a)
Identification. (1) Rigid pedicle screw systems are comprised of multiple components, made from a variety of materials that allow the surgeon to build an implant system to fit the patient's anatomical and physiological requirements. Such a spinal implant assembly consists of a combination of screws, longitudinal members (e.g., plates, rods including dual diameter rods, plate/rod combinations), transverse or cross connectors, and interconnection mechanisms (e.g., rod-to-rod connectors, offset connectors).(2) Semi-rigid systems are defined as systems that contain one or more of the following features (including but not limited to): Non-uniform longitudinal elements, or features that allow more motion or flexibility compared to rigid systems.
(b)
Classification. (1) Class II (special controls), when intended to provide immobilization and stabilization of spinal segments in skeletally mature patients as an adjunct to fusion in the treatment of the following acute and chronic instabilities or deformities of the thoracic, lumbar, and sacral spine: severe spondylolisthesis (grades 3 and 4) of the L5-S1 vertebra; degenerative spondylolisthesis with objective evidence of neurologic impairment; fracture; dislocation; scoliosis; kyphosis; spinal tumor; and failed previous fusion (pseudarthrosis). These pedicle screw spinal systems must comply with the following special controls:(i) Compliance with material standards;
(ii) Compliance with mechanical testing standards;
(iii) Compliance with biocompatibility standards; and
(iv) Labeling that contains these two statements in addition to other appropriate labeling information:
“Warning: The safety and effectiveness of pedicle screw spinal systems have been established only for spinal conditions with significant mechanical instability or deformity requiring fusion with instrumentation. These conditions are significant mechanical instability or deformity of the thoracic, lumbar, and sacral spine secondary to severe spondylolisthesis (grades 3 and 4) of the L5-S1 vertebra, degenerative spondylolisthesis with objective evidence of neurologic impairment, fracture, dislocation, scoliosis, kyphosis, spinal tumor, and failed previous fusion (pseudarthrosis). The safety and effectiveness of these devices for any other conditions are unknown.”
“Precaution: The implantation of pedicle screw spinal systems should be performed only by experienced spinal surgeons with specific training in the use of this pedicle screw spinal system because this is a technically demanding procedure presenting a risk of serious injury to the patient.”
(2) Class II (special controls), when a rigid pedicle screw system is intended to provide immobilization and stabilization of spinal segments in the thoracic, lumbar, and sacral spine as an adjunct to fusion in the treatment of degenerative disc disease and spondylolisthesis other than either severe spondylolisthesis (grades 3 and 4) at L5-S1 or degenerative spondylolisthesis with objective evidence of neurologic impairment. These pedicle screw systems must comply with the following special controls:
(i) The design characteristics of the device, including engineering schematics, must ensure that the geometry and material composition are consistent with the intended use.
(ii) Non-clinical performance testing must demonstrate the mechanical function and durability of the implant.
(iii) Device components must be demonstrated to be biocompatible.
(iv) Validation testing must demonstrate the cleanliness and sterility of, or the ability to clean and sterilize, the device components and device-specific instruments.
(v) Labeling must include the following:
(A) A clear description of the technological features of the device including identification of device materials and the principles of device operation;
(B) Intended use and indications for use, including levels of fixation;
(C) Identification of magnetic resonance (MR) compatibility status;
(D) Cleaning and sterilization instructions for devices and instruments that are provided non-sterile to the end user; and
(E) Detailed instructions of each surgical step, including device removal.
(3) Class II (special controls), when a semi-rigid system is intended to provide immobilization and stabilization of spinal segments in the thoracic, lumbar, and sacral spine as an adjunct to fusion for any indication. In addition to complying with the special controls in paragraphs (b)(2)(i) through (v) of this section, these pedicle screw systems must comply with the following special controls:
(i) Demonstration that clinical performance characteristics of the device support the intended use of the product, including assessment of fusion compared to a clinically acceptable fusion rate.
(ii) Semi-rigid systems marketed prior to the effective date of this reclassification must submit an amendment to their previously cleared premarket notification (510(k)) demonstrating compliance with the special controls in paragraphs (b)(2)(i) through (v) and paragraph (b)(3)(i) of this section.