Methods for manufacturing implants having integration surfaces

Abstract

A method of producing an interbody spinal implant. The method includes the steps of obtaining a blank having a top surface, bottom surface, opposing lateral sides, and opposing anterior and posterior portions, and applying a subtractive process (e.g., masked acid etching) to the top surface, the bottom surface, or both surfaces of the blank to form a roughened surface topography. Subsequently, the blank is machined to form the interbody spinal implant, which includes a body having a top surface, a bottom surface, opposing lateral sides, opposing anterior and posterior portions, a substantially hollow center, and a single vertical aperture where the top surface, the bottom surface, or both surfaces of the interbody spinal implant have the roughened surface topography produced by the subtractive process. This simplified method produces more accurate and repeatable implants with fewer process steps and defects, reducing process time and costs.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application is a continuation-in-part of U.S. patent application Ser. No. 12 / 151,198, filed on May 5, 2008, and pending, which is a continuation-in-part of U.S. patent application Ser. No. 11 / 123,359, filed on May 6, 2005, and issued as U.S. Pat. No. 7,662,186. The contents of both prior applications are incorporated by reference into this document, in their entirety and for all purposes.TECHNICAL FIELD[0002]The present invention relates generally to improved methods of making interbody spinal implants and, more particularly, to an optimized sequence of process steps necessary to faun spinal implants having integration surfaces of better quality with reduced process time and costs.BACKGROUND OF THE INVENTION[0003]In the simplest terms, the spine is a column made of vertebrae and discs. The vertebrae provide the support and structure of the spine while the spinal discs, located between the vertebrae, act as cushions or “shock absorber...

AI Technical Summary

Benefits of technology

[0008]The present invention provides for interbody spinal implants produced by simplified and optimized methods, which allow each step to be utilized without constraining the subsequent processes or degrading the previous process steps. The process of the present invention can use the same raw materials as traditional implant manufacturing methods, but with fewer process steps and fewer transitions during the manufacturing process. The dimensions and surface features of the implant may be produced in a more accurate and repeatable fashion. In addition, the need for hand processing or special machining can be minimized or eliminated. For at least these reasons, the production time and costs may also be reduced in producing the implants.

[0009]In one embodiment, the present invention provides a method of producing an interbody spinal implant including obtaining a blank (e.g., from a supplier or manufacturing the blank from raw materials) comprising a top surface, a bottom surface, opposing lateral sides, and opposing anterior and posterior portions, and applying a subtractive process, such as masked acid etching, to at least a portion the top surface, the bottom surface, or both surfaces of the blank to form a roughened surface topography. After the subtractive process, the blank is machined (e.g., milled, turned, or the like) to form an interbody spinal implant. The interbody spinal implant has a body with a top surface and a bottom surface, where the top surface, the bottom surface, or both surfaces of the interbody spinal implant have the roughened surface topography formed by the subtractive process. The implant also includes opposing lateral sides and opposing anterior and posterior portions—all formed from the blank. The implant is also machined to have a substantially hollow center, and a single vertical aperture (a) extending from the top surface to the bottom surface of the body, (b) having a size and shape predetermined to maximize the surface area of the top surface and the bottom surface available proximate the anterior and posterior portions while maximizing both radiographic visualization and access to the substantially hollow center, and (c) defining a transverse rim. The implant may be machined to have additional features, such as at least one transverse aperture, one or more holes, and the like.

[0011]Various implant body shapes are provided to allow for implantation through various access paths to the spine through a patient's body. The structures and surfaces are designed to work in concert to preserve endplate bone structures, provide for sufficient bioactivity in each respective location, and provide stability within the disc space and the graft containment axial column. In particular, the shapes and textures of the bioactive surfaces vary based on the implant insertion path, location within the disc space, and frictional characteristics of the surfaces.

[0015]The resulting implant, for a solid body implant or a composite implant, comprises at least one integration surface having a roughened surface topography where the entire implant or the integration plate was produced by such a process that the surfaces and edges of the implant are of high quality and reliability. Thus, the resulting surfaces are uniform and consistent providing high yields, the locations of the surface enhancements are not limited and are not degraded by subsequent processing, and the process does not require hand processing or costly machining in order to meet all required specifications.

Problems solved by technology

Over time, the discs may become diseased or infected, may develop deformities such as tears or cracks, or may simply lose structural integrity (e.g., the discs may bulge or flatten).

Impaired discs can affect the anatomical functions of the vertebrae, due to the resultant lack of proper biomechanical support, and are often associated with chronic back pain.

There are a number of problems, however, with traditional spinal implants including, but not limited to, improper seating of the implant, implant subsidence (defined as sinking or settling) into the softer cancellous bone of the vertebral body, poor biomechanical integrity of the endplates, damaging critical bone structures during or after implantation, and the like.

Such challenges include: (1) end-plate preparation; (2) implant difficulty; (3) materials of construction; (4) implant expulsion; (5) implant subsidence; (6) insufficient room for bone graft; (7) stress shielding; (8) lack of implant incorporation with vertebral bone; (9) limitations on radiographic visualization; and (10) cost of manufacture and inventory.

The location of such surface enhancements may be limited by the capabilities of the manufacturing process, the resulting surfaces may be non-uniform or inconsistent providing low yields, and the process may require hand processing or costly machining steps in order to provide high-quality implants meeting all required specifications.

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