(105 days)
The KRD1™ Pedicle Screw System is 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 instabilities or deformities of the thoracic, lumbar, and sacral spine: degenerative spondylolisthesis with objective evidence of neurological impairment, fracture, dislocation, scoliosis, kyphosis, spinal tumor, and failed previous fusion (Pseudoarthrosis).
In addition, the KRD1™ Pedicle Screw System is indicated for the treatment of severe spondylolisthesis (Grade 3 and 4) of the L5-S1 vertebra in skeletally mature patients receiving fusion by autogenous bone graft.
The KRD1™ Pedicle Screw System consists of longitudinal rods, polyaxial screws, transverse connectors, and instrumentation to facilitate installation of this system.
The KRD11M Pedicle Screw is offered in multiple screw diameters, with multiple lengths to accommodate individual patient needs. KRD1™ Pedicle Screw assemblies consist of the screw, a tulip, and a washer that secures the tulip to the screw and also serves as the saddle for the longitudinal rod. The tulip and screw designs allow the screw to have a polyaxial rotation relative to the tulip. A locking cap is placed on top of the pedicle screw assembly to secure the position of the implant and to retain the longitudinal rod.
The KRD1™ Pedicle Screw assembly serves as the central fixation device to which various rods and cross connectors are secured to provide desired fixation.
Longitudinal rods are provided in two configurations, straight and lordotic, have a fixed diameter (5.5mm), and vary by length.
Cross connector assemblies are provided in multiple configurations, varying by length. Cross connectors are used to provide additional fixation support.
The KRD1™ Pedicle Screw System components are fabricated from medical grade titanium alloy conforming to ASTM F-136 specifications.
This document describes the KRD1™ Pedicle Screw System, a spinal fixation device, and its acceptance criteria for regulatory approval.
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criteria | Reported Device Performance |
|---|---|
| Substantial equivalence to predicate devices in: | Shown to be substantially equivalent to predicate devices in: |
| - Indications for use | - Indications for use |
| - Function | - Function |
| - Operating principles | - Operating principles |
| - Materials | - Materials |
| Performance (mechanical testing) | Performance (mechanical testing) was conducted and demonstrated substantial equivalence to predicate devices. |
| Clinical data | Not required for this device type and demonstrated substantial equivalence. |
2. Sample Size Used for the Test Set and Data Provenance
The document does not explicitly mention a "test set" in the context of clinical or performance data that would typically have a sample size for evaluation. Instead, the device's performance was established through mechanical testing and comparison to predicate devices, rather than through clinical trials with patient-specific test sets. Therefore, details regarding sample size for a "test set" and data provenance (country of origin, retrospective/prospective) are not applicable in the conventional sense for this type of device submission. The "data" provenance would refer to the mechanical testing results themselves.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Qualifications
As clinical data or a patient-based "test set" requiring expert ground truth were not required or performed, this information is not applicable. The ground truth for device performance was established through engineering and biomechanical principles in mechanical testing.
4. Adjudication Method for the Test Set
Since no patient-based "test set" was utilized, an adjudication method for such a set is not applicable.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
A Multi-Reader Multi-Case (MRMC) comparative effectiveness study was not performed as this device relies on mechanical testing and comparison to predicates for substantial equivalence, not on human reader performance with or without AI assistance. Therefore, there is no effect size reported for human readers with AI vs. without AI assistance.
6. Standalone (Algorithm Only Without Human-in-the-Loop Performance) Study
This device is a physical pedicle screw system, not an algorithm or AI-driven software. Therefore, a standalone (algorithm only) performance study is not applicable.
7. Type of Ground Truth Used
The ground truth used for establishing the device's performance and safety was primarily based on mechanical testing results and comparison of these results, as well as design and material specifications, against established performance characteristics of legally marketed predicate spinal fixation devices. This implies that the 'ground truth' is adherence to engineering standards and established safety and efficacy profiles of similar devices.
8. Sample Size for the Training Set
As this is a physical medical device and not an AI/ML algorithm requiring a training set, the concept of a "training set" and its sample size is not applicable.
9. How Ground Truth for the Training Set Was Established
Since there is no "training set" for this physical device, the method for establishing its ground truth is not applicable.
§ 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.