(219 days)
Surgical stabilization to assist bony fusion of the cervical spine and cervical occipital junction.
Indications For Use:
- Degenerative disk disease of the cervical vertebrae (neck pain of discogenic origin with degeneration of the disc as confirmed by patient history and radiographic studies)
- spondylolisthesis of the cervical vertebrae
- Spinal stenosis of the cervical vertebrae
- Atlanto/axial fracture with instability
- Cervical-occipital dislocation
- Revision of previous cervical spine surgery
- Tumors
The Ransford Cervical Fixation System consists of various loops (in stainless steel and titanium, with different angles and lengths), stainless steel and titanium cross links, and surgical instruments. These implants are designed for use with annealed stainless steel wire 0.9mm diameter (20swg) or multi-filament braided titanium alloy (6A),4V) cable, 0.045 inch (1.1mm) diameter, 19 inches long with a 3 inch, soft, pure titanium mono-filament lead wire. The system is based on sublaminar wires and contoured rods placed posteriorly.
The provided text is a 510(k) Premarket Notification for the RANSFORD CERVICAL FIXATION SYSTEM™, which is a medical device. The primary method for proving the device meets acceptance criteria in a 510(k) submission is to demonstrate substantial equivalence to an already legally marketed predicate device. This is achieved through comparison of design, materials, intended use, and performance data.
Based on the document, here's an analysis of the acceptance criteria and the study that proves the device meets them:
1. Acceptance Criteria and Reported Device Performance
The acceptance criteria here are implicitly defined by the characteristics of the predicate device, the Hartshill Spinal Fixation System (K853033). The RANSFORD CERVICAL FIXATION SYSTEM™ must perform "substantially the same" as the predicate device.
| Feature / Acceptance Criteria | Reported Device Performance (RANSFORD CERVICAL FIXATION SYSTEM™) |
|---|---|
| Intended Use: Surgical stabilization of the cervical spine and cervical occipital junction. | Surgical stabilization alone and surgical stabilization and fusion of the cervical spine and cervical occipital junction. (Same as predicate) |
| Indications for Use: | Degenerative disk disease, spondylolisthesis, spinal stenosis, atlanto/axial fracture with instability, cervical-occipital dislocation, revision of previous cervical spine surgery, tumors. (Same cervical indications for use as predicate) |
| Materials: Stainless Steel | Titanium and stainless steel (Evolutionary improvement: also uses Titanium, which is noted to offer enhanced clinical performance in axial extension and axial compression tests, and titanium cables show increased stiffness and force at gross failure compared to stainless steel wires). |
| Surgical Approach: Posterior | Posterior (Same as predicate) |
| Method of Attachment: Wires to occiput and posterior arches. | Wires to occiput and posterior arches (Same as predicate) |
| Axial Torsion Performance: Similar stiffness, torque at gross failure, and angular rotation at gross failure as the predicate. | No statistically significant difference in stiffness, torque at gross failure, and angular rotation at gross failure for titanium Ransford Loop vs. stainless steel Hartshill Cervical Rectangle. Mean stiffness and torque at gross failure are higher for titanium Ransford, and mean angle at gross failure is lower. |
| Axial Extension Performance: Similar stiffness, force at gross failure, and extension at gross failure as the predicate. | Statistically significant increase in stiffness, increase in the force at gross failure, and decrease in the extension at gross failure for titanium Ransford Loop vs. stainless steel Hartshill Cervical Rectangle. This is believed to enhance clinical performance. |
| Axial Compression Performance: Similar stiffness, force at gross failure, and extension at gross failure as the predicate. | Statistically significant increase in stiffness, increase in the force at gross failure, and increase in the extension at gross failure for titanium Ransford Loop vs. stainless steel Hartshill Cervical Rectangle. This is believed to enhance clinical performance. |
| Cable/Wire Tensile Strength: Similar performance to predicate. | Statistically significant increase in stiffness and force at gross failure of titanium cables compared to stainless steel wires. Wires have longer extension to gross failure than cables. |
| Sterilization: Able to be sterilized effectively. | Recommended sterilization method is gravity steam sterilization for 30 minutes at 121°C (250° F) with a Sterility Assurance Level (SAL) of 10⁻⁶. Validation conducted by qualified commercial laboratories using the overkill method based on HIMA & AORN protocols. (This demonstrates effective sterilization, similar to what would be expected for a predicate device). |
2. Sample Size Used for the Test Set and Data Provenance
The "test set" in this context refers to the samples used in the static mechanical tests. The document does not explicitly state the exact sample sizes for each mechanical test (Axial Torsion, Axial Extension, Axial Compression, Cable/Wire Tensile Test). It refers to "tests conducted" without providing N numbers.
The data provenance is laboratory-based mechanical testing, comparing the RANSFORD CERVICAL FIXATION SYSTEM™ components (titanium Ransford Loop and titanium cables) directly to components of the Hartshill Spinal Fixation System (stainless steel Hartshill Cervical Rectangle and stainless steel wires). There is no mention of human subject data, animal data, or clinical data in this safety and effectiveness summary. The tests were "conducted by qualified commercial laboratories." The country of origin for the testing is not specified, but the manufacturer is based in England.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Qualifications
This information is not applicable in this context. Ground truth is typically established in studies involving diagnostic devices or algorithms that interpret data (e.g., medical images). For a mechanical fixation system like this, the "ground truth" is defined by the physical properties and performance characteristics measured in static mechanical tests. The "experts" are the "qualified commercial laboratories" that conducted the tests, and their "qualifications" implicitly relate to their ability to perform such mechanical testing according to established protocols.
4. Adjudication Method for the Test Set
This is not applicable. Adjudication methods like 2+1 or 3+1 are used to resolve disagreements among human readers or experts in diagnostic studies. For mechanical tests, the results are quantitative measurements, and statistical comparisons determine whether differences are significant. There is no human interpretation or adjudication in the sense described here.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was Done
No, a Multi-Reader Multi-Case (MRMC) comparative effectiveness study was not done. This type of study involves human readers (e.g., radiologists, pathologists) evaluating cases, often with and without AI assistance, to assess diagnostic performance. The RANSFORD CERVICAL FIXATION SYSTEM™ is a spinal implant, not a diagnostic device, so such a study would not be relevant.
6. If a Standalone (Algorithm Only Without Human-in-the-Loop Performance) Was Done
This question is not applicable as the RANSFORD CERVICAL FIXATION SYSTEM™ is a physical surgical implant, not an algorithm or AI system. Its performance is assessed through mechanical testing, not through standalone algorithm performance.
7. The Type of Ground Truth Used
The "ground truth" for the mechanical testing is based on direct physical measurement of mechanical properties (stiffness, torque, force, angular rotation, extension) under controlled laboratory conditions, as compared to the established performance of the predicate device. It is a performance benchmark against a known, legally marketed device.
8. The Sample Size for the Training Set
This information is not applicable. "Training set" refers to data used to train machine learning models. This device is a physical implant, not an AI system, and therefore has no training set.
9. How the Ground Truth for the Training Set Was Established
This information is not applicable for the same reasons as in point 8.
§ 888.3050 Spinal interlaminal fixation orthosis.
(a)
Identification. A spinal interlaminal fixation orthosis is a device intended to be implanted made of an alloy, such as stainless steel, that consists of various hooks and a posteriorly placed compression or distraction rod. The device is implanted, usually across three adjacent vertebrae, to straighten and immobilize the spine to allow bone grafts to unite and fuse the vertebrae together. The device is used primarily in the treatment of scoliosis (a lateral curvature of the spine), but it also may be used in the treatment of fracture or dislocation of the spine, grades 3 and 4 of spondylolisthesis (a dislocation of the spinal column), and lower back syndrome.(b)
Classification. Class II.