(120 days)
The Nano FortiFix® System is intended to provide immobilization of spinal segments in skeletally mature patients as an adjunct to fusion in the non-cervical spine for the following indications: DDD (defined as back pain of discogenic origin with degeneration of the disc confirmed by history and radiographic studies), spinal stenosis, spondylolisthesis, spinal deformities (i.e., scoliosis, and/ or lordosis), trauma (i.e., fracture or dislocation), tumor, pseudarthrosis and/or failed previous fusion.
Nano FortiFix® is a posterior pedicle screw system consisting of rods, polyaxial pedicle screws, connectors and fasteners in a variety of sizes to accommodate differing anatomic requirements. The Nano FortiFix® pedicle screw shaft is available with or without a nanosurface. The Nano FortiFix® nano pedicle screw has a micro- and nano-roughened surface that demonstrates the requirements for nanotechnology. The surface of the nano screw threads has been deliberately manipulated to produce nanoscale dimensions which exhibit specific properties. These threads are electrochemically treated to possess a controlled nanotopography composed of nanotube arrays having a pore size diameter between 30-90 nanometers. Calcium and phosphate are incorporated into the nanotube surface.
This report focuses on the Nano FortiFix® System, a thoracolumbosacral pedicle screw system, and assesses its substantial equivalence to predicate devices, particularly concerning its use of nanotechnology.
1. Table of Acceptance Criteria and Reported Device Performance
The provided document doesn't explicitly state quantitative acceptance criteria for device performance from a clinical trial in the typical sense of accuracy, sensitivity, or specificity. Instead, the "acceptance criteria" are implied through comparative mechanical testing and in vitro evaluations demonstrating substantial equivalence to predicate devices and adherence to specific standards for the nanosurface.
| Acceptance Criteria (Implied) | Reported Device Performance |
|---|---|
| Mechanical Performance | |
| Meet or exceed performance of predicate devices per ASTM F1717 | Mechanical testing of the worst-case construct (static/dynamic compression and static torsion) and polyaxial screw pull-off testing demonstrated that the Nano FortiFix® performance is substantially equivalent to the predicate devices. |
| Nanosurface Properties (Biological) | |
| Enhanced mineralization compared to other surfaces | In vitro evaluations showed that the Nano FortiFix nanosurface develops statistically significantly greater mineralization in both osteoblast and mesenchymal stem cell cultures compared to other surfaces. This addresses the "Points to Consider" in the FDA's Guidance for Industry: Considering Whether an FDA-Regulated Product Involves the Application of Nanotechnology. |
| Biocompatibility (absence of harmful endotoxins) | Bacterial endotoxin testing was conducted in accordance with AAMI ST72:2011 and met the specified testing limit. |
| Technological Characteristics | |
| Same basic design as predicate devices | Basic design (rod and screw system) is the same. |
| Same implant grade materials as predicate devices | Implant grade materials (titanium alloy, cobalt chrome) are the same. Nano FortiFix® System implants are manufactured from titanium alloy (ASTM F136). Rods are additionally manufactured from cobalt chrome (ASTM F1537). |
| Similar sizes/dimensions as predicate devices | Sizes (dimensions) are within those offered by the predicates. |
| Intended Use | |
| Same as predicate devices | The Nano FortiFix® System has the same intended use as the predicate devices: immobilization and stabilization of spinal segments in skeletally mature patients as an adjunct to fusion in the non-cervical spine for various indications (DDD, spinal stenosis, spondylolisthesis, spinal deformities, trauma, tumor, pseudarthrosis, failed previous fusion). |
| Regulatory Compliance (Nanotechnology) | |
| Address "Points to Consider" in FDA Nanotechnology Guidance | In vitro evaluations as described above confirm the nanosurface's specific properties and address the guidance for product involving nanotechnology. The surface of the nano screw threads has been deliberately manipulated to produce nanoscale dimensions which exhibit specific properties, electrochemically treated to possess a controlled nanotopography composed of nanotube arrays (30-90 nm pore size diameter), with calcium and phosphate incorporated. |
2. Sample Size Used for the Test Set and Data Provenance
The document does not specify a "test set" in the context of patient data or clinical imaging. The evaluations are primarily in vitro and mechanical.
- Mechanical Testing: "Worst case construct" and "worst case subconstruct" were tested. The exact number of samples for these tests is not provided, but it implies a representative selection.
- In Vitro Evaluations: Osteoblast (OB) and mesenchymal stem cell (MSC) cultures were used to quantify mineralization. The number of samples/replicates for these cultures is not specified.
- Bacterial Endotoxin Testing: Conducted in accordance with AAMI ST72:2011. The number of samples is not specified.
Data Provenance: All data appears to be from laboratory and bench testing, rather than human clinical data. Therefore, there is no mention of country of origin or whether the data is retrospective or prospective in a clinical sense.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
This information is not applicable as the study described is not a clinical study involving the establishment of ground truth by human experts (e.g., radiologists interpreting images). The "ground truth" for the mechanical and in vitro tests is based on established engineering and biological standards and methodologies.
4. Adjudication Method for the Test Set
Not applicable. There was no clinical PIVOTAL study with a test set requiring adjudication from a panel of experts. The evaluations were laboratory-based (mechanical, in vitro, endotoxin).
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. The Nano FortiFix® System is a medical implant (pedicle screw system), not an AI diagnostic tool. Therefore, an MRMC study comparing human reader performance with and without AI assistance is not relevant to this device.
6. If a standalone (i.e. algorithm only, without human-in-the-loop performance) was done
Not applicable. The Nano FortiFix® System is a medical implant, not an algorithm.
7. The type of ground truth used
The "ground truth" for the substantial equivalence determination for this device is based on:
- Mechanical Standards: Adherence to ASTM F1717 for static and dynamic mechanical properties.
- Biological Standards: In vitro demonstration of statistically significant enhanced mineralization in osteoblast and mesenchymal stem cell cultures (a functional biological outcome related to bone integration) and meeting bacterial endotoxin limits (safety).
- Material Science Standards: Use of materials compliant with ASTM F136 (titanium alloy) and ASTM F1537 (cobalt chrome).
- Regulatory Guidance: Adherence to FDA's "Points to Consider" for nanotechnology in medical devices.
8. The sample size for the training set
Not applicable. This device is not an AI/ML algorithm that requires a training set.
9. How the ground truth for the training set was established
Not applicable. There is no training set as this is not an AI/ML device.
§ 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.