Sheet based triply periodic minimal surface implants for promoting osseointegration and methods for producing same
Inventors
MILLER, Andrew Todd • Rexrode, Matthew • Kelly, Cambre • Gall, Ken
Assignees
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Publication Number
US-12667461-B1
Publication Date
2026-06-30
Expiration Date
Abstract
Provided herein are implants and methods for producing implants. In at least one embodiment, the implants include sheet-based, triply periodic, minimal surface (TPMS) portions. According to one embodiment, the TPMS portions include a gyroid architecture that provides for improved osseointegration and mechanical performance over previous implants due to novel ratios of porosity to compressive strength, among other features. In one or more embodiments, the gyroid architecture is organized into unit cells that demonstrate anisotropic mechanical performance along an insertion direction. In various embodiments, the present methods include novel selective laser melting (SLM) techniques for forming the TPMS portions of implants in a manner that reduces defect formation, thereby improving compressive performance and other implant properties.
Core Innovation
The described 3D-printed spinal implant combines a non-porous titanium frame with an integrally formed porous sheet-based triply periodic minimal surface portion fabricated via powder bed fusion. The porous portion extends from the top surface to the bottom surface, comprises unit cells, is node- and strut-free, and directly contacts bone upon implantation. Disclosed examples utilize a gyroid architecture to combine porosity for bone ingrowth with compressive strength while reducing stress concentrations.
Unit-cell dimensions and wall thickness tune porosity, stiffness modulus, and compressive strength, wherein unequal cell dimensions provide directional mechanical properties. The claims further specify a wall thickness of 0.25 mm to 1.0 mm, an opening devoid of structure bisecting the porous portion, and an opening for receiving instrumentation. Because the background section is omitted in the provided content, the problem being solved is not explicitly described in patent.
Claims Coverage
The claims include two independent claims covering 3D-printed spinal implants with an integrally formed porous sheet-based triply periodic minimal surface portion and a non-porous titanium frame.
Implant with a perimeter frame and equation-defined porous portion
Independent claim 1 recites a titanium, non-porous frame encompassing the outer perimeter of the top surface and a node- and strut-free porous sheet-based triply periodic minimal surface portion integrally formed with the frame via powder bed fusion. The portion extends from the top surface to the bottom surface, is defined by unit cells with the stated base equation, has a wall thickness of 0.25 mm to 1.0 mm, and defines a structure-free opening that bisects the portion. The top-surface portion directly contacts bone upon implantation, and at least one side, back, or front surface defines an opening for receiving instrumentation.
Implant with a titanium frame and sinusoidally defined porous portion
Independent claim 10 recites a node- and strut-free porous sheet-based triply periodic minimal surface portion integrally formed with a non-porous titanium frame via powder bed fusion, bounded at its outer perimeter by the frame. The portion extends from the top surface to the bottom surface, at least partially comprises the back surface, is defined by unit cells with a base geometry defined by a sinusoidal equation, has a wall thickness of 0.25 mm to 1.0 mm, and defines a structure-free opening that bisects the portion. The portion directly contacts bone upon implantation and exhibits an ultimate compression strength of about 50.0–230.0 MPa.
The independent claims cover spinal implant configurations combining a non-porous titanium frame with an integrally formed, node- and strut-free porous sheet-based triply periodic minimal surface portion configured for bone contact. They specify structural features including a bisecting opening and wall thickness, differing in equation definitions, instrumentation openings, and specified compression strength.
Stated Advantages
The disclosed design combines bone-ingrowth porosity with compressive strength while reducing stress concentrations.
The disclosed gyroid-sheet examples show favorable combinations of high porosity and compressive strength across the plotted porosity range compared with literature TPMS data.
The described selective laser melting parameter refinements reduce wall defects and increase measured wall density.
Documented Applications
The 3D-printed implant is a spinal implant, with disclosed embodiments including spinal cages configured to directly contact bone upon implantation.
Disclosed embodiments include osteotomy wedges.
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