(73 days)
When intended for pedicle screw fixation from T1-S1, the indications include 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: degenerative disc disease (defined as discogenic back pain with degeneration of the disc confirmed by history and radiographic studies), degenerative spondylolisthesis with objective evidence of neurologic impairment, fracture, dislocation, deformities or curvatures (i.e. scoliosis, kyphosis, and/or lordosis), tumor and failed previous fusion.
As a pedicle screw system placed between L3 and S1, the indications include Grade 3 or Grade 4 spondylolisthesis, when utilizing autograft or allograft, when affixed to the posterior lumbosacral spine, and intended to be removed after the solid fusion is established.
The existing, commercially available Zimmer Spine PathFinder NXT® Minimally Invasive Pedicle Screw System ("PathFinder NXT System") consists of various screws, rods and associated accessories and is intended to provide temporary stabilization following surgery to fuse the spine. The PathFinder NXT screws are polyaxial cannulated designs with a range of spinal rod lengths. The PathFinder NXT System allows the surgeon to place polyaxial pedicle screws either through an open or mini-open procedure. The percutaneous insertion rods are for minimally invasive procedures. The PathFinder NXT System is designed to aid in the surgical correction of several types of spinal conditions and intended only to provide stabilization during the development of a solid fusion with a bone graft. These implants are intended to be removed after the development of a solid fusion mass.
Additionally, the PathFinder NXT System includes instrumentation to facilitate the implantation of the PathFinder NXT implants.
The provided document describes the acceptance criteria and the study conducted for the Zimmer Spine PathFinder NXT® Minimally Invasive Pedicle Screw System to demonstrate its substantial equivalence to predicate devices, rather than an AI/ML device. Therefore, many of the requested fields, such as those pertaining to AI/ML specific studies (e.g., sample size for test set, data provenance, number of experts for ground truth, adjudication method, MRMC study, standalone performance, training set sample size, and ground truth for training set) are not applicable to this submission.
The acceptance criteria for this medical device are based on demonstrating substantial equivalence to legally marketed predicate devices in terms of design, materials, function, and intended use. The study focuses on performance testing to confirm this equivalence.
Here's a summary based on the provided text, with "N/A" for fields not relevant to this type of medical device submission:
1. Table of acceptance criteria and the reported device performance
| Acceptance Criteria (Demonstrates Substantial Equivalence via) | Reported Device Performance |
|---|---|
| Bench Testing (per ASTM F1717 & F1798 standards): | - Implants, polyaxial screws, and rods confirmed to have product performance suitable for intended use. |
| - Static compression bending | |
| - Static torsion testing | |
| - Dynamic compression bending | |
| - Static axial grip | |
| - Static torsion grip | |
| - Static flexion-extension bending | |
| Cadaver Lab Testing (Human Factors): | - Evaluated human factors regarding the combination of instrument design changes and labeling design changes, as well as interaction with implants. Confirmed substantial equivalence of these changes compared to predicate devices. |
| Biocompatibility Testing: | - Ensured the subject device materials are biocompatible after manufacturing, based on minor design changes made in comparison to predicate devices. |
| Sterilization, Dry Time, and Cleaning Testing: | - Ensured the subject device's steam sterilization, cleaning, and dry time requirements and instructions are substantially equivalent to the predicate devices. |
| Overall Substantial Equivalence: | - Zimmer Spine considers the subject device's product performance to be substantially equivalent to its predicate devices because there are no changes to the product performance specifications or device functional scientific technology compared to the predicate PathFinder NXT® Minimally Invasive Pedicle Screw System and Sequoia® Pedicle Screw System. |
2. Sample size used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective)
- Sample Size for Test Set: Not explicitly stated for specific tests (e.g., number of screws, rods tested). The document mentions "components of the subject PathFinder NXT® Minimally Invasive Pedicle Screw System" were reviewed and tested.
- Data Provenance: Not specified, but generally, bench and cadaver lab testing for FDA submissions are conducted by manufacturers or contracted labs, likely within the United States or other regulated regions. The nature of the tests (bench, cadaver) is inherently prospective within a controlled lab environment.
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. This is a physical device and not an AI/ML system requiring expert-derived ground truth for image interpretation or diagnosis. The "ground truth" here is adherence to engineering standards and functional performance. However, cadaver lab testing would involve surgical experts for evaluation. The qualifications of these experts are not detailed.
4. Adjudication method (e.g. 2+1, 3+1, none) for the test set
- Not applicable. This is not an AI/ML system requiring adjudication of interpretations. Performance is measured against engineering standards and functional requirements.
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 is not an AI/ML system.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done
- Not applicable. This is not an AI/ML system. The device itself is a "standalone" surgical implant system.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc)
- The "ground truth" for this medical device's performance testing is based on:
- Engineering Standards: Adherence to established ASTM F1717 and F1798 standards for mechanical performance.
- Biocompatibility Standards: Ensuring materials meet medical-grade biocompatibility requirements.
- Functional Equivalence: Demonstrating that changes to the device (e.g., instrument design, labeling) do not negatively impact the intended function or safety when compared to predicate devices, including evaluation in cadaver labs for human factors.
8. The sample size for the training set
- Not applicable. This is not an AI/ML system that uses a training set.
9. How the ground truth for the training set was established
- Not applicable. This is not an AI/ML system.
§ 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.