The TOWNLEY Pedicle Screw Plating System is intended to stabilize the spine as an aid to fusion. After first making drill holes in the pedicles, a DYNA-LOK® plate is positioned of the pedicles. TOWNLEY Pedicle screws are then inserted through the DYNA-LOK® plate, down the center of the pedicles, and into the vertebral body. Bone graft must be used with each procedure.

This system is indicated for the treatment of any or all of the following at the C2 to S1 (inclusive) spinal levels: (a) Trauma, including spinal fractures and/or dislocations; (b) Spondylolisthesis; (c) Spondylolysis; (d) Pseudarthrosis or failed previous fusions which are symptomatic or which may cause secondary instability or deformity; (e) Degenerative disc disease and/or degenerative diseases which include: (1) degenerative disc disease (DDD) as defined by neck and/or back pain of discogenic origin as confirmed by radiographic studies; and/or (2) degenerative disease of the facets with instability.

Device Description

This system consists of a broad-headed, partially threaded screw designed to compress bone grafts. Screw lengths range from 0.5 to 2.5 inches. Both cortical and cancellous screw threads are available. The screw comes in two configurations: flat-head or hex. The hex screws are slightly wider in diameter. The stainless steel DYNA-LOK® plates are used to interconnect two or more vertebrae together via screw fixation through the pedicles. All components are fabricated from medical grade stainless steel (ASTM F-138 or its ISO equivalent).

AI/ML Overview

This document is a 510(k) summary for the TOWNLEY Pedicle Screw Plating System. It focuses on demonstrating substantial equivalence to a predicate device rather than presenting a study proving the device meets specific acceptance criteria in the way a clinical trial for a new drug or an AI-powered diagnostic device would.

Therefore, the requested information components related to an AI/diagnostic device study (such as sample size for test sets, data provenance, number of experts for ground truth, adjudication methods, MRMC studies, standalone performance, training set details) are not applicable to this type of regulatory submission.

The "acceptance criteria" here are essentially the demonstration of "substantial equivalence" to a legally marketed predicate device, as required for a 510(k) clearance by the FDA. The "study" proving it meets these criteria is the provided documentation itself, which asserts its similarity.

Here's a breakdown of what can be extracted from the provided text, aligned as much as possible with your request, but highlighting the inapplicability of many points:

1. Table of Acceptance Criteria and Reported Device Performance

Acceptance Criteria (Demonstrated for 510(k) Substantial Equivalence)	Reported Device Performance/Characteristics
Product Description:	TOWNLEY Pedicle Screw Plating System:
- Screw design	- Broad-headed, partially threaded screw designed to compress bone grafts.
- Screw lengths	- 0.5 to 2.5 inches.
- Screw thread types	- Both cortical and cancellous screw threads available.
- Screw configurations	- Flat-head or hex (hex screws slightly wider in diameter).
- Plate usage	- Stainless steel DYNA-LOK® plates used to interconnect two or more vertebrae via screw fixation through pedicles.
- Materials	- All components fabricated from medical grade stainless steel (ASTM F-138 or its ISO equivalent).
Indications for Use:	Intended to stabilize the spine as an aid to fusion (with bone graft). Indicated for C2 to S1 levels for:
- Trauma	- Trauma, including spinal fractures and/or dislocations.
- Spondylolisthesis	- Spondylolisthesis.
- Spondylolysis	- Spondylolysis.
- Pseudarthrosis/Failed fusions	- Pseudarthrosis or failed previous fusions which are symptomatic or which may cause secondary instability or deformity.
- Degenerative disc disease (DDD)	- Degenerative disc disease (DDD) as defined by neck and/or back pain of discogenic origin as confirmed by radiographic studies. (Note: FDA letter clarifies this to require patient history and radiographic studies).
- Degenerative facet disease	- Degenerative disease of the facets with instability.
Performance Data/Comparison:	The document states "Documentation was provided which demonstrated the TOWNLEY Pedicle Screw Plating System was demonstrated to be substantially equivalent to itself." This implies comparison to a previously cleared version of the same device or a very similar predicate. No specific performance metrics are provided in the way a clinical study would. The FDA letter confirms the device is "substantially equivalent" for the specified indications when following the general controls and specific warnings/limitations.
Material Equivalence	All components fabricated from medical grade stainless steel (ASTM F-138 or its ISO equivalent), which is a common and accepted material for such implants.
Labeling Requirements	The FDA's acceptance includes specific labeling requirements, warnings, and limitations regarding pedicle screw fixation indications to ensure safe use and compliance.

2. Sample size used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective)

Not applicable. This document describes a 510(k) submission, which relies on demonstrating substantial equivalence to a predicate device, not primary clinical performance data from a test set. There is no mention of a "test set" in the context of device performance data.

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. No such test set or ground truth establishment by experts is described for this type of regulatory submission. The "ground truth" for a 510(k) is typically the established safety and effectiveness of the legally marketed predicate device.

4. Adjudication method (e.g. 2+1, 3+1, none) for the test set

Not applicable. No test set or adjudication process is mentioned.

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 mechanical implant, not an AI-powered diagnostic tool, and therefore MRMC studies are irrelevant.

6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done

Not applicable. This device is a mechanical implant, not an algorithm.

7. The type of ground truth used (expert consensus, pathology, outcomes data, etc.)

Not applicable. For a 510(k) of this nature, the "ground truth" is typically the regulatory acceptance of the predicate device based on its known characteristics, indications, and safety/effectiveness profile, which has already been established through prior regulatory processes (potentially including clinical data or consensus standards). The submission argues the new device is sufficiently similar to that predicate.

8. The sample size for the training set

Not applicable. This device is a mechanical implant, not an AI model requiring a training set.

9. How the ground truth for the training set was established

Not applicable. This device is a mechanical implant, not an AI model, and therefore has no training set or associated ground truth establishment.

In summary, the provided document is a 510(k) premarket notification, a regulatory pathway for medical devices that are substantially equivalent to already legally marketed devices. It does not contain information on clinical studies or performance data in the way a submission for a novel diagnostic or AI device would. The "study" demonstrating criteria fulfillment is the comparison and argument for substantial equivalence to a predicate device.

Summary

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JUL 1 3 1998

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K982154

Requlatory Affairs Department

TOWNLEY Pedicle Screw Plating System 510(k) Summary

Sofamor Danek USA Company: I. 1800 Pyramid Place Memphis, TN 38132 (901) 396-3133

Proprietary Trade Name: TOWNLEY Pedicle Screw Plating System II.

Product Description III.

IV. Indications

This system is indicated for the treatment of any or all of the following at the C2 to S1 (inclusive) spinal levels: (a) Trauma, including spinal fractures and/or dislocations: (b) Spondylolisthesis: (c) Spondylolysis; (d) Pseudarthrosis or failed previous fusions which are symptomatic or which may cause secondary instability or deformity; (e) Degenerative disc disease and/or degenerative diseases which include: (1) degenerative disc disease (DDD) as defined by neck and/or back pain of discogenic origin as confirmed by radiographic studies; and/or (2) degenerative disease of the facets with instability.

V. Substantial Equivalence

Documentation was provided which demonstrated the TOWNLEY Pedicle Screw Plating System was demonstrated to be substantially equivalent to itself.

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Image /page/1/Picture/2 description: The image shows the logo for the U.S. Department of Health & Human Services. The logo consists of a circular seal with the text "DEPARTMENT OF HEALTH & HUMAN SERVICES - USA" around the perimeter. Inside the circle is a stylized image of three human profiles facing right, stacked on top of each other. The profiles are rendered in black and have a flowing, abstract design.

JUL 1 3 1998

Food and Drug Administration 9200 Corporate Boulevard Rockville MD 20850

Richard W. Treharne, Ph.D. · Vice President Research and Regulatory Affairs Sofamor Danek 1800 Pyramid Place Memphis, Tennessee 38132

Re: K982154 Townley Pedicle Screw Plating System Regulatory Class: II Product Codes: MNI, MNH and KWP Dated: June 18, 1998 Received: June 19, 1998

Dear Dr. Treharne:

We have reviewed your Section 510(k) notification of intent to market the device system referenced above and we have determined the device system is substantially equivalent (for the indications for use stated in the enclosure) to device systems marketed in interstate commerce prior to May 28, 1976 or to devices that have been reclassified in accordance with the provisions of the Federal, Food, Drug, and Cosmetic Act (Act).

You may, therefore, market your device system subject to the general controls provisions of the Act and the limitations identified below. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration. Note that labeling or otherwise promoting this device system for pedicular screw fixation/attachment for indications other than that described in item 2 below, would cause the device system to be adulterated under 501(f)(1) of the Act.

This device system, when intended for pedicular screw fixation/attachment to the spine for indications other than that described in item 2 below, is a class III device under Section 513(f) of the Act. Class III devices are required to have an approved premarket approval (PMA) application prior to marketing. Accordingly:

1. The package label must state that there are labeling limitations.
1. The package insert must prominently state that the device system, as a pedicle screw fixation system, is intended only for the following:

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Page 2 - Richard W. Treharne, Ph.D.

trauma, including fractures and/or dislocations; a.
degenerative disc disease and/or degenerative diseases which include: b.
- (1) degenerative disc disease (ddd) as defined by back and/or neck pain of discogenic origin as confirmed by patient history with degeneration of the disc as confirmed by radiographic studies and/or
- degenerative disease of the facets with instability; (2)
spondvlolysis: C.
d. spondylolisthesis, all grades and types; and
e. pseudarthrosis.

For all of these indications, bone graft must be used and the system is limited to screw fixation from C2 to S1; and

1. The package insert must also include the following WARNINGS:
- As a pedicle screw fixation system, this subject system is intended only for ● the following:
  - trauma, including fractures and/or dislocations;
  - degenerative disc disease and/or degenerative diseases which include:
    - degenerative disc disease (ddd) as defined by back and/or neck (1) pain of discogenic origin as confirmed by patient history with degeneration of the disc as confirmed by radiographic studies and/or
    - (2) degenerative disease of the facets with instability;
  - spondylolysis;
  - spondylolisthesis, all grades and types; and
  - pseudarthrosis.

For all of these indications, bone graft must be used and the system is limited to screw fixation from C2 to S1.

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Page 3 - Richard W. Treharne, Ph.D.

Benefit of spinal fusions utilizing any pedicle screw fixation system has not . been adequately established in patients with stable spines.
Potential risks identified with the use of this device system, which may . require additional surgery, include: device component fracture, loss of fixation, non-union, fracture of the vertebra, neurological injury, and vascular or visceral injury.

See Warnings, Precautions, and Potential Adverse Events sections of the package insert for a complete list of potential risks.

Any pedicular screw fixation/attachment for intended uses other than that described 4. by item 2 above, for this device is considered investigational and may only be investigated as a significant risk device in accordance with the investigational device exemption (IDE) regulations under 21 CFR, Part 812. All users of the device for pedicular screw fixation/attachment for intended uses other than that described above, must receive approval from their respective institutional review boards (IRBs) and the Food and Drug Administration (FDA) prior to conducting an investigation.
1. Any previous warning statements identified as part of previous 510(k) clearances or required by OC/Labeling and Promotion which stated that a component/system was not approved for screw fixation into the pedicles of the spine must be replaced by the warnings of item 3 above.

FDA advises that the use of your device system with any other device components but those identified in this 510(k) would require submission of a new 510(k) providing documentation of design, material, and labeling compatibility between the device components. Mechanical testing of a spinal system consisting of the subject device components and other device components, whether yours or those of other manufacturers, may also be required.

If your device is classified (see above) into either class II (Special Controls) or class III (Premarket Approval), it may be subject to such additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 895. A substantially equivalent determination assumes compliance with the current Good Manufacturing Practice requirement, as set forth in the Quality System Regulation (QS) for Medical Devices: General regulation (21 CFR Part 820) and that, through periodic (QS) inspections, the Food and Drug Administration (FDA) will verify such assumptions. Failure to comply with the GMP regulation may result in regulatory action. In addition, FDA may publish further announcements concerning your device in the Federal Register. Please note: this response to your premarket notification submission does not affect any obligation you might have under sections 531 through 542 of the Act for devices under the Electronic Product Radiation Control provisions, or other Federal Laws or Regulations.

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Page 4 - Richard W. Treharne, Ph.D.

This letter will allow you to begin marketing your device as described in your 510(k) premarket notification immediately. An FDA finding of substantial equivalence of your device to a legally marketed predicate device results in a classification for your device and permits your device to proceed to the market.

If you desire specific advice for your device on our labeling regulation (21 CFR Part 801 and additionally 809.10 for in vitro diagnostic devices), please contact the Office of Compliance at (301) 594-4659. Additionally, for questions on the promotion and advertising of your device, please contact the Office of Compliance at (301) 594-4639. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR 807.97). Other general information on your responsibilities under the Act may be obtained from the Division of Small Manufacturers Assistance at its toll-free number (800) 638-2041 or at (301) 443-6597, or at its Internet address "http://www.fda.gov/cdrh/dsmamain.html".

Sincerely yours,

fu
Celia M. Witten, Ph.D., M.D.
Director
Division of General and
Restorative Devices
Office of Device Evaluation
Center for Devices and
Radiological Health

Enclosure

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510(k) Number (if known): K982154

Device Name: _________________________________________________________________________________________________________________________________________________________________ TOWNLEY Pedicle Screw Plating System

Indications for Use:

(PLEASE DO NOT WRITE BELOW THIS LINE-CONTINUE ON ANOTHER PAGE IF NEEDED)

Concurrence of CDRH, Office of Evaluation (ODE)

Prescription Use
(Per 21 CFR 801.109)
(Optional 1-2-96)
OR
Over-the-counter Use

(Division
Division
evices
510(k) Numbe
K982154

Regulation Number and Section

§ 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.