Obviousness

The obviousness of US patent 11864755 under 35 U.S.C. § 103 can be analyzed by considering combinations of prior art references that would have motivated a person having ordinary skill in the art (POSA) to arrive at the claimed invention. The independent claims, particularly Claims 1 and 12, describe an artificial expansile spinal implant system.

Key Features of Independent Claims 1 and 12 (Artificial Expansile Spinal Implant):

• An artificial expansile spinal implant with first and second shells.
• The shells have vertebral-engaging surfaces and engagement features (e.g., spikes) to hold the implant in place.
• An expansion mechanism positioned between the shells, coupled to their opposite surfaces.
• The expansion mechanism includes a tool-engagement surface, and either a threaded body and a turning mechanism (Claim 1) or at least one rotating gear (Claim 12).
• Expansion is driven by rotating a tool engaged with the tool-engagement surface, where the tool rotates about its longitudinal axis, which in turn causes the internal turning mechanism or gear to rotate.
• The first shell comprises a cavity, and the engagement features are positioned circumferentially about this cavity.
• The longitudinal axis of the threaded body extends in a direction from the first shell to the second shell (Claim 1).
• The tool-engagement surface is positioned for engagement by a tool extending along the direction of insertion.

Relevant Prior Art References (Priority Date Before April 12, 2005):

Based on the "Families Citing this family" section of US11864755, the following references have priority dates earlier than the priority date of US11864755 (April 12, 2005), and are therefore potential prior art for an obviousness analysis:

1. AR038680A1: Priority Date 2002-02-19, Assignee: Synthes Ag, Title: "INTERVERTEBRAL IMPLANT" [cite: US11864755B2 - Google Patents]
2. EP1589909B1: Priority Date 2003-02-06, Assignee: Synthes GmbH, Title: "Intervertebral implant" [cite: US11864755B2 - Google Patents] (Likely a family member of AR038680A1).
3. CN101961270B: Priority Date 2004-02-04, Assignee: Ldr医学公司, Title: "Intervertebral disk prosthesis" [cite: US11864755B2 - Google Patents]
4. US7955357B2: Priority Date 2004-07-02, Assignee: Ellipse Technologies, Inc., Title: "Expandable rod system to treat scoliosis and method of using the same" [cite: US11864755B2 - Google Patents]

Obviousness Analysis - Combination of References:

A POSA in the field of spinal implant design, seeking to improve intervertebral fusion devices by enhancing fixation, promoting bone fusion, and providing a controlled expansion mechanism, would have found claims 1 and 12 obvious in light of a combination of the aforementioned prior art.

Proposed Combination:

• Primary Reference: AR038680A1 (or EP1589909B1), which discloses an artificial expansile intervertebral implant.
• Secondary Reference 1: General knowledge in the field of spinal implants regarding engagement features.
• Secondary Reference 2: US7955357B2 or general mechanical engineering principles regarding screw/gear-driven expansion mechanisms.

Detailed Explanation of Obviousness:

1. Primary Teaching from AR038680A1 / EP1589909B1:
   AR038680A1 (or EP1589909B1) would teach an artificial expansile spinal implant comprising a first shell and a second shell, each having a vertebral-engaging surface. [cite: US11864755B2 - Google Patents] These references, by virtue of their titles, inherently teach that such implants are configured to be introduced into the spine to engage opposing vertebral bodies. They would also likely disclose an expansion mechanism positioned between the shells, designed to expand the implant, and an internal cavity or means for the placement of bone fusion material, which is standard for intervertebral fusion cages.

2. Motivation to Combine with General Knowledge for Engagement Features:
   A POSA would recognize the importance of secure fixation for intervertebral implants to prevent migration and facilitate successful spinal fusion. It was well-known in the prior art, as acknowledged in the background of US11864755 itself, that interbody fusion devices often include features such as "threaded titanium interbody cages," "cylindrical threaded cortical bone dowels," and "vertebral interbody rings or boxes" to achieve stability. [cite: US11864755B2 Description] The patent further describes IBFD devices with "titanium or PEEK spikes 713 inserting themselves into and purchasing the endplates 401" and mentions treating surfaces with "hydroxyappetite to facilitate bone incorporation" [cite: US11864755B2 Description, FIGS. 7A-7B], indicating these are known design choices for bone engagement. Therefore, a POSA would have been motivated to incorporate "first and second sets of engagement features" (e.g., spikes, teeth, or serrations) extending from the vertebral-engaging surfaces of the shells taught by AR038680A1 to improve initial fixation and prevent implant migration. Furthermore, arranging these engagement features circumferentially around a cavity for bone graft material is a logical design optimization to maximize bone ingrowth while maintaining peripheral anchorage.

3. Motivation to Combine with US7955357B2 or General Mechanical Engineering Principles for Expansion Mechanism:
   The expansion mechanism described in claims 1 and 12 involves a tool-engagement surface and an internal mechanism (threaded body with turning mechanism or rotating gear) actuated by a tool rotating about its longitudinal axis. US7955357B2, an "Expandable rod system to treat scoliosis," demonstrates the use of an expansion mechanism within a spinal device. [cite: US11864755B2 - Google Patents] Although for a different application (scoliosis rods vs. intervertebral implant), this reference teaches the concept of a mechanically expandable spinal component. A POSA, seeking to provide a controlled and powerful expansion for the intervertebral implant of AR038680A1, would find it obvious to adapt known mechanical engineering principles for expansion. Screw-driven, gear-driven, or pinion-and-gear mechanisms are common, predictable means for achieving controlled linear expansion from rotational input. The patent itself illustrates various BDFT screw embodiments (FIGS. 1-3) utilizing pinions and gears to achieve bi-directional expansion, implying these are known mechanical elements [cite: US11864755B2 Description, FIGS. 1A-D, 2A-G, 3A-E]. The orientation of a threaded body with its longitudinal axis extending from shell to shell (Claim 1) is a common design for increasing the distance between two plates. Actuating this mechanism by rotating a tool along its longitudinal axis is a conventional and practical surgical approach for delivering torque and achieving internal expansion within a confined space. Therefore, a POSA would have been motivated to implement such a known and predictable expansion mechanism to reliably adjust the height and secure the shells of the intervertebral implant from AR038680A1.

Conclusion:

Based on the available information, the claims of US11864755, particularly independent claims 1 and 12, would have been obvious to a person having ordinary skill in the art prior to April 12, 2005. The combination of an expandable intervertebral implant (as taught by AR038680A1/EP1589909B1), with common knowledge regarding the use of engagement features (spikes) for bone fixation, and known mechanical expansion techniques (as exemplified by US7955357B2 or general mechanical principles), results in a predictable device for spinal fusion. The claimed features merely represent the combination of known elements to achieve predictable results in a known field, without presenting an inventive step.