US 11864755

US patent 11864755, titled "Artificial expandable implant systems," was granted to Moskowitz Family LLC on January 9, 2024, from an application filed on March 22, 2021 (Application number US17/208,640). The inventors are Mosheh T. Moskowitz and Nathan C. Moskowitz.

The abstract describes an apparatus and method for joining members using either a self-drilling screw apparatus or a stapling apparatus. The screw apparatus features a shell containing first and second threaded screw members with tapered ends. A drive mechanism rotates these screw members in opposite directions, embedding them into the members to be joined. This screw apparatus can be applied to bones, spinal columns, vertebral bodies, wood, building materials, metals, masonry, or plastics. The stapling apparatus consists of two lever arms that pivot at a fulcrum, with cartridges at their ends holding staples. When the lever arms are brought together, the staples interlock. These staples can also be used to join bones, portions of the spinal column, or vertebral bodies.

A plain-language overview of the independent claims is as follows:

• Independent Claim 1: This claim describes an artificial spinal implant system that is designed to expand. It includes a first shell and a second shell, each having a surface with features (like spikes) that grip the vertebrae. An expansion mechanism is situated between these shells, connected to their inner surfaces. This mechanism has a threaded body and a turning mechanism, and a surface where a tool can engage. When a tool is rotated, it causes the turning mechanism to operate, expanding the implant to push the shells apart and embed their gripping features into the opposing vertebral bodies. The tool-engagement surface is accessible by a tool inserted along the implant's direction of insertion. The first shell also has a through-hole (cavity), and the gripping features are arranged around this cavity.
• Independent Claim 12: This claim also describes an artificial spinal implant system configured for expansion. It features a first shell and a second shell, both with vertebral-engaging surfaces and engagement features. An expansion mechanism is located between these shells, connected to their inner surfaces, and includes a tool-engagement surface and at least one rotating gear. When a tool is rotated via the tool-engagement surface, it causes the gear to rotate, which drives the expansion of the implant between the shells. The implant is designed to engage and hold onto opposing vertebral bodies through its engagement features upon expansion. Similar to Claim 1, the tool-engagement surface is positioned for engagement by a tool extending along the direction of insertion, and the first shell has a cavity with engagement features circumferentially positioned around it.

Regarding litigation, a search of the CAFC 2026 dockets for US patent 11864755 did not yield any results as of April 26, 2026. However, the provided patent data indicates ongoing litigation related to the patent family in other forums, including:

• "Global patent litigation dataset” by Darts-ip shows litigation filed for family ID 40583835, which includes US11864755B2.
• A US case was filed in the Minnesota District Court (case 0:25-cv-00769).
• A PTAB case, IPR2026-00121, has been filed and is pending.
  I do not have authoritative information on the details or current status of these litigation cases.US patent 11864755, titled "Artificial expandable implant systems," was granted to Moskowitz Family LLC on January 9, 2024, from an application filed on March 22, 2021 (Application number US17/208,640). The inventors are Mosheh T. Moskowitz and Nathan C. Moskowitz.

The abstract describes an apparatus and method for joining members using either a self-drilling screw apparatus or a stapling apparatus. The screw apparatus features a shell containing first and second threaded screw members with tapered ends. A drive mechanism rotates these screw members in opposite directions, embedding them into the members to be joined. This screw apparatus can be applied to bones, spinal columns, vertebral bodies, wood, building materials, metals, masonry, or plastics. The stapling apparatus consists of two lever arms that pivot at a fulcrum, with cartridges at their ends holding staples. When the lever arms are brought together, the staples interlock. These staples can also be used to join bones, portions of the spinal column, or vertebral bodies.

A plain-language overview of the independent claims is as follows:

• Independent Claim 1: This claim describes an artificial spinal implant system that is designed to expand. It includes a first shell and a second shell, each having a surface with features (like spikes) that grip the vertebrae. An expansion mechanism is situated between these shells, connected to their inner surfaces. This mechanism has a threaded body and a turning mechanism, and a surface where a tool can engage. When a tool is rotated, it causes the turning mechanism to operate, expanding the implant to push the shells apart and embed their gripping features into the opposing vertebral bodies. The tool-engagement surface is accessible by a tool inserted along the implant's direction of insertion. The first shell also has a through-hole (cavity), and the gripping features are arranged around this cavity.
• Independent Claim 12: This claim also describes an artificial spinal implant system configured for expansion. It features a first shell and a second shell, both with vertebral-engaging surfaces and engagement features. An expansion mechanism is located between these shells, connected to their inner surfaces, and includes a tool-engagement surface and at least one rotating gear. When a tool is rotated via the tool-engagement surface, it causes the gear to rotate, which drives the expansion of the implant between the shells. The implant is designed to engage and hold onto opposing vertebral bodies through its engagement features upon expansion. Similar to Claim 1, the tool-engagement surface is positioned for engagement by a tool extending along the direction of insertion, and the first shell has a cavity with engagement features circumferentially positioned around it.

Regarding litigation, a search of the CAFC 2026 dockets for US patent 11864755 did not yield any results as of April 26, 2026. However, the provided patent data indicates ongoing litigation related to the patent family in other forums, including:

• "Global patent litigation dataset” by Darts-ip shows litigation filed for family ID 40583835, which includes US11864755B2.
• A US case was filed in the Minnesota District Court (case 0:25-cv-00769).
• A PTAB case, IPR2026-00121, has been filed and is pending.
  I do not have authoritative information on the details or current status of these litigation cases.US patent 11864755, titled "Artificial expandable implant systems," was granted to Moskowitz Family LLC on January 9, 2024, from an application filed on March 22, 2021 (Application number US17/208,640). The inventors are Mosheh T. Moskowitz and Nathan C. Moskowitz.

The abstract describes an apparatus and method for joining members using either a self-drilling screw apparatus or a stapling apparatus. The screw apparatus features a shell containing first and second threaded screw members with tapered ends. A drive mechanism rotates these screw members in opposite directions, embedding them into the members to be joined. This screw apparatus can be applied to bones, spinal columns, vertebral bodies, wood, building materials, metals, masonry, or plastics. The stapling apparatus consists of two lever arms that pivot at a fulcrum, with cartridges at their ends holding staples. When the lever arms are brought together, the staples interlock. These staples can also be used to join bones, portions of the spinal column, or vertebral bodies.

A plain-language overview of the independent claims is as follows:

• Independent Claim 1: This claim describes an artificial spinal implant system that is designed to expand. It includes a first shell and a second shell, each having a surface with features (like spikes) that grip the vertebrae. An expansion mechanism is situated between these shells, connected to their inner surfaces. This mechanism has a threaded body and a turning mechanism, and a surface where a tool can engage. When a tool is rotated, it causes the turning mechanism to operate, expanding the implant to push the shells apart and embed their gripping features into the opposing vertebral bodies. The tool-engagement surface is accessible by a tool inserted along the implant's direction of insertion. The first shell also has a through-hole (cavity), and the gripping features are arranged around this cavity.
• Independent Claim 12: This claim also describes an artificial spinal implant system configured for expansion. It features a first shell and a second shell, both with vertebral-engaging surfaces and engagement features. An expansion mechanism is located between these shells, connected to their inner surfaces, and includes a tool-engagement surface and at least one rotating gear. When a tool is rotated via the tool-engagement surface, it causes the gear to rotate, which drives the expansion of the implant between the shells. The implant is designed to engage and hold onto opposing vertebral bodies through its engagement features upon expansion. Similar to Claim 1, the tool-engagement surface is positioned for engagement by a tool extending along the direction of insertion, and the first shell has a cavity with engagement features circumferentially positioned around it.

Regarding litigation, a direct search for US patent 11864755 in the CAFC 2026 dockets did not explicitly return this specific patent number. However, the assignee, Moskowitz Family LLC, is involved in a case (24-1696, Moskowitz Family LLC v. Globus Medical, Inc.) listed on the U.S. Court of Appeals for the Federal Circuit's May 2026 schedule. The provided patent data also indicates that the patent family has ongoing litigation, including a US case filed in the Minnesota District Court (case 0:25-cv-00769) and a pending PTAB case (IPR2026-00121). I do not have authoritative information on the details or current status of these litigation cases.

Known litigation involving US patent 11864755 includes the following cases:

1. US District Court Case

   • Jurisdiction: Minnesota District Court [cite: US11864755B2 - Google Patents]
   • Case Number: 0:25-cv-00769 [cite: US11864755B2 - Google Patents]
   • Filing Date: Not explicitly stated on the Google Patents page.
   • Plaintiff(s): Not explicitly stated on the Google Patents page.
   • Defendant(s): Not explicitly stated on the Google Patents page.
   • Outcome or Current Status: Listed as "litigation" [cite: US11864755B2 - Google Patents].

2. PTAB Case

   • Jurisdiction: Patent Trial and Appeal Board (PTAB) [cite: US11864755B2 - Google Patents]
   • Case Number: IPR2026-00121 [cite: US11864755B2 - Google Patents]
   • Filing Date: Not explicitly stated on the Google Patents page, but the case number suggests it was filed in 2026.
   • Plaintiff(s) (Petitioner): Unified Patents [cite: US11864755B2 - Google Patents]
   • Defendant(s) (Patent Owner/Respondent): Not explicitly stated on the Google Patents page, but typically the patent owner (Moskowitz Family LLC) would be the respondent.
   • Outcome or Current Status: Pending [cite: US11864755B2 - Google Patents].

Proceedings overview

There is one AIA trial proceeding on file for US patent 11864755. This proceeding is currently active with a status of "Trial Instituted". Given the early stage of this single proceeding, the patent's claims remain largely untested in AIA trials, offering a defendant potential grounds for challenging validity.

IPR2026-00121 — Medtronic, Inc. v. Moskowitz Family LLC

• Type: Inter Partes Review
• Filed: 2025-11-10
• Status: Trial Instituted (meaning the PTAB has authorized a trial to proceed on at least some of the challenged claims and grounds).
• Judge panel: Not publicly available at this time.
• Petition grounds: Not publicly available at this time without reviewing the full petition and institution decision. However, IPRs typically challenge claims under 35 U.S.C. §§ 102 and 103 based on patents and printed publications.
• Institution decision: The trial was instituted. The exact date of institution is not provided in the prompt but the "last modified" date of 2026-05-18 suggests recent activity, likely related to the institution decision or subsequent scheduling. Without the full decision, the specific claims and reasoning for institution are not available.
• Final Written Decision: Not yet issued.
• Settlement / termination: Not applicable, as the proceeding is active.
• Appeal: Not applicable, as no Final Written Decision has been issued.
• Defensive value: This active IPR indicates that at least some claims of US11864755 have been deemed likely unpatentable by the PTAB to warrant a trial. A defendant facing assertion of this patent should closely monitor this proceeding, as a successful challenge could invalidate asserted claims.

Strategic summary

Only one AIA trial proceeding, IPR2026-00121, has been filed against US patent 11864755, and it is currently active with "Trial Instituted" status. This means the PTAB has found a reasonable likelihood that at least one claim challenged by Medtronic, Inc. will be found unpatentable. Consequently, the claims of this patent are currently UNTESTED by a Final Written Decision in a PTAB trial. Without the institution decision, it's not possible to specify which claims have been challenged and on what grounds.

The estoppel landscape under 35 U.S.C. § 315(e)(2) will only become relevant for Medtronic, Inc. (and its privies) after a Final Written Decision is issued. If claims are determined to be unpatentable, those claims (and any claims that reasonably could have been raised) will be estopped for the petitioner in future proceedings. For other potential defendants, the prior art grounds raised in this IPR are still available for their own challenges, provided they are not in privity with Medtronic, Inc. The involvement of Medtronic, Inc., a major medical device company, indicates a significant commercial interest in challenging this patent.

Recommended next steps

• Monitor IPR2026-00121 closely: As a defendant, it is critical to obtain and review the institution decision for IPR2026-00121 to understand which claims are being challenged and on what prior art grounds. The PTAB has a statutory deadline of one year from institution to issue a Final Written Decision. Identify key upcoming trial milestones such as potential oral hearings and the projected Final Written Decision due date.
• Evaluate challenged claims: Determine if any claims currently being asserted against you (if applicable) are among those challenged in IPR2026-00121. If so, a favorable outcome for the petitioner could directly benefit your defense.
• Consider filing your own IPR: If your product infringes claims not challenged in IPR2026-00121, or if you have strong prior art grounds distinct from those raised by Medtronic, Inc., consider initiating your own Inter Partes Review. The ongoing IPR might offer insights into the patent owner's defense strategies.

Inventors

• Mosheh T. MOSKOWITZ (Employer not determinable from patent text; likely self-employed or associated with the Moskowitz Family LLC)
• Nathan C. Moskowitz (Employer not determinable from patent text; likely self-employed or associated with the Moskowitz Family LLC)

There are no unusual patterns indicating all inventors departing the original assignee within 12 months of filing. The assignments show the inventors assigning their rights to entities related to them (Nathan C. Moskowitz, then Moskowitz Family LLC) during the patent prosecution phase of the application that matured into this patent.

Original assignee

The entity named on the issued patent is Moskowitz Family LLC. It is unclear if Moskowitz Family LLC ships a product embodying the claims. The primary line of business appears to be intellectual property management related to medical devices, particularly spinal implants, as described in the patent. Its current status is operating, as it holds the patent.

Assignment timeline

• 2021-05-19 (executed) / recorded 2021-05-25 — Reel 003881/0879

  • Conveyance: ASSIGNMENT OF ASSIGNORS INTEREST
  • Assignor: MOSKOWITZ, MOSHEH T.
  • Assignee: MOSKOWITZ, NATHAN C.
  • Correspondent: BROWDY AND NEIMARK, P.L.L.C., 1625 K STREET, NW, SUITE 1100, WASHINGTON, DC 20006. This correspondent recurs in this chain.
  • Context: Internal transfer of inventor's rights to another individual.

• 2021-05-19 (executed) / recorded 2021-05-25 — Reel 003881/0883

  • Conveyance: ASSIGNMENT OF ASSIGNORS INTEREST
  • Assignor: MOSKOWITZ, NATHAN C.
  • Assignee: MOSKOWITZ FAMILY LLC
  • Correspondent: BROWDY AND NEIMARK, P.L.L.C., 1625 K STREET, NW, SUITE 1100, WASHINGTON, DC 20006. This correspondent recurs in this chain.
  • Context: Internal transfer of inventor's rights to a family-controlled LLC, establishing the original assignee for the issued patent.

No further post-issuance assignments are recorded for US11864755 on the USPTO Assignment Center as of 2026-05-26.

Timeline diagram

timeline
    title Ownership of US 11864755
    2005 : Priority date
    2021 : Application filed by Moskowitz Family LLC
         : Mosheh T Moskowitz assigns to Nathan C Moskowitz
         : Nathan C Moskowitz assigns to Moskowitz Family LLC
    2024 : Patent issued to Moskowitz Family LLC

NPE / troll-pattern signals

1. Shell-entity transfer — unclear. The transfers are from individual inventors to a "Family LLC." While "LLC" can suggest a shell, the "Family" aspect might indicate a closely-held operating business or an entity formed to manage family assets. Without product information or a registered-agent address being clearly distinct from a business operation, it's difficult to confirm definitively. The patent family has been involved in litigation, suggesting an assertive approach to patents.
2. Known asserter in the chain — not present. Moskowitz Family LLC is not identified as a known NPE on major public lists.
3. Repeat correspondent across the chain — present. BROWDY AND NEIMARK, P.L.L.C. (1625 K STREET, NW, SUITE 1100, WASHINGTON, DC 20006) appears as the correspondent on both recorded assignments (Reel 003881/0879 and 003881/0883). This indicates a consistent legal representative for the transfers within the family.
4. Cascading transfers — unclear. There are two transfers on the same day (executed 2021-05-19, recorded 2021-05-25) from individual inventors to a family-controlled LLC. While consecutive, they represent a direct chain from inventors to the ultimate applicant/assignee for this patent, rather than multiple transfers through unrelated or shell entities.
5. Pre-litigation transfer — unclear. The patent family (ID=40583835) has litigation filed (2025-08-23 anticipates expiration, PTAB case IPR2026-00121 filed). However, the assignments for this specific patent (US11864755) occurred in 2021, prior to its issuance in 2024 and well before any listed litigation dates in 2025-2026.
6. Bankruptcy fire-sale — not present. No indication of bankruptcy from the original assignors or assignee.
7. Privateering — not present. No evidence of an operating company transferring the patent to an NPE to assert on its behalf.
8. Defensive aggregator (anti-NPE) — not present. The patent is currently held by Moskowitz Family LLC, not a defensive aggregator.

Verdict

NPE — moderate confidence

The primary signal is the consistent use of a "Family LLC" as the assignee, combined with a repeat correspondent handling the transfers from individual inventors to this LLC (Browdy and Neimark, P.L.L.C. on Reel 003881/0879 and 003881/0883). While not a definitively "known asserter" or a typical "shell-entity" name, "Family LLC" often serves as a patent-holding vehicle for individual inventors, especially given the lack of evidence of product shipment by this entity. The Google Patents record also notes ongoing litigation for this patent family, which is consistent with an assertive (NPE) strategy.

USPTO Assignment Center search for US11864755: https://assignmentcenter.uspto.gov/

To identify the most relevant prior art for US patent 11864755, I will search the USPTO database for the patent and then examine its cited references.

Here is the analysis of the most relevant prior art for US patent 11864755, based on the citations provided within the patent document itself:

US Patent 11864755 - Artificial expandable implant systems

Most Relevant Prior Art (based on internal citations and relevance to the independent claims):

1. US 7,704,279 B2

   • Full Citation: US 7,704,279 B2, "Bi-directional fixating transvertebral body screws, zero-profile horizontal intervertebral miniplates, expansile intervertebral body fusion devices, and posterior motion-calibrating interarticulating joint stapling device for spinal fusion," issued April 27, 2010. [cite: US11864755B2 - Google Patents]
   • Publication/Filing Date: The filing date of the application that matured into US 7,704,279 B2 was August 23, 2005, and it claims benefit from Provisional Application No. 60/670,231, filed on April 12, 2005. [cite: US11864755B2 Description] The publication date is April 27, 2010. [cite: US11864755B2 - Google Patents]
   • Brief Description: This patent describes bidirectional fixating transvertebral (BDFT) screws, zero-profile horizontal intervertebral miniplates, expansile intervertebral body fusion devices (IBFDs), and a posterior motion-calibrating interarticulating joint stapling device for spinal fusion. It specifically details BDFT screw mechanisms, including those that achieve bi-directional movement via a central gear engaging left and right screws (similar to Embodiment I of US11864755) and designs where a narrower solid screw is buried within a wider hollow screw for greater expansion (similar to Embodiments II and III of US11864755). It also introduces the concept of IBFDs with ratchetable shells and spikes for engaging vertebral endplates, and mentions an optional porous elastomeric balloon sheath for bone fusion material. [cite: US11864755B2 Description]
   • Potential Anticipation (35 U.S.C. § 102): US 7,704,279 B2 is explicitly identified as a parent patent (US application Ser. No. 11/208,644) from which US11864755 claims benefit. Therefore, its content is considered prior art to US11864755 and is highly relevant. It appears to anticipate many aspects of Claims 1 and 12, particularly the core concepts of an expansile spinal implant with vertebral-engaging features, an internal expansion mechanism (screw/gear driven), and shells (e.g., "expansile titanium or PEEK shells" and their spikes). [cite: US11864755B2 Description] For example, the description of IBFD device 700 with "ratchetable titanium or PEEK shells 710, 711 which can expand geometrically in two dimensions" and "spikes 713 inserting themselves into and purchasing the endplates 401" directly anticipates the first and second shells with engagement features of claims 1 and 12. [cite: US11864755B2 Description] The "four fixed height screws 712" for height expansion could also anticipate the expansion mechanism. [cite: US11864755B2 Description] The BDFT screws themselves, described in detail in US 7,704,279 B2, are also incorporated into the IBFD device 700. [cite: US11864755B2 Description]

2. US 7,951,180 B2

   • Full Citation: US 7,951,180 B2, "Bi-directional fixating transvertebral body screws, zero-profile horizontal intervertebral miniplates, expansile intervertebral body fusion devices, and posterior motion-calibrating interarticulating joint stapling device for spinal fusion," issued May 31, 2011. [cite: US11864755B2 - Google Patents]
   • Publication/Filing Date: The filing date of the application that matured into US 7,951,180 B2 was December 31, 2008, and it is a continuation of US application Ser. No. 11/208,644 (US 7,704,279 B2). [cite: US11864755B2 Description]
   • Brief Description: As a continuation patent, it shares significant disclosure with US 7,704,279 B2, covering the BDFT screws, mini-plates, expansile IBFDs, and facet stapling devices for spinal fusion. [cite: US11864755B2 Description]
   • Potential Anticipation (35 U.S.C. § 102): This patent, being a continuation of the direct parent, would also anticipate the same elements of Claims 1 and 12 for the same reasons as US 7,704,279 B2. [cite: US11864755B2 Description]

3. US 9,924,940 B2

   • Full Citation: US 9,924,940 B2, "Bi-directional fixating transvertebral body screws, zero-profile horizontal intervertebral miniplates, expansile intervertebral body fusion devices, and posterior motion-calibrating interarticulating joint stapling device for spinal fusion," issued March 27, 2018. [cite: US11864755B2 - Google Patents]
   • Publication/Filing Date: The filing date of the application that matured into US 9,924,940 B2 was April 25, 2011, and it is a continuation of US application Ser. No. 13/093,812. [cite: US11864755B2 Description]
   • Brief Description: Another continuation patent in the family, it further elaborates on the BDFT screws, zero-profile mini-plates, expansile IBFDs, and facet stapling for spinal fusion. [cite: US11864755B2 Description]
   • Potential Anticipation (35 U.S.C. § 102): As another continuation, US 9,924,940 B2 would similarly anticipate relevant aspects of Claims 1 and 12, given its shared lineage and disclosure with the earlier patents in the family. [cite: US11864755B2 Description]

4. US 10,251,643 B2

   • Full Citation: US 10,251,643 B2, "Bi-directional fixating transvertebral body screws, zero-profile horizontal intervertebral miniplates, expansile intervertebral body fusion devices, and posterior motion-calibrating interarticulating joint stapling device for spinal fusion," issued April 9, 2019. [cite: US11864755B2 - Google Patents]
   • Publication/Filing Date: The filing date of the application that matured into US 10,251,643 B2 was March 23, 2018, and it is a continuation of US application Ser. No. 15/934,622. [cite: US11864755B2 Description]
   • Brief Description: This patent is another continuation, covering the same core inventions of BDFT screws, mini-plates, expansile IBFDs, and facet stapling devices. [cite: US11864755B2 Description]
   • Potential Anticipation (35 U.S.C. § 102): Being a continuation of the family, this patent also fully anticipates the elements of Claims 1 and 12 for the same reasons as the previous family members. [cite: US11864755B2 Description]

5. US 10,952,723 B2

   • Full Citation: US 10,952,723 B2, "Artificial intervertebral implant," issued March 9, 2021. [cite: US11864755B2 - Google Patents]
   • Publication/Filing Date: The filing date of the application that matured into US 10,952,723 B2 was March 22, 2019, and it is a continuation of US application Ser. No. 16/362,152. [cite: US11864755B2 Description]
   • Brief Description: This patent is a direct parent to US11864755. It focuses on artificial intervertebral implants. [cite: US11864755B2 Description] Given that US11864755 is a continuation of this patent, it will contain substantially similar or identical disclosures regarding the core implant structures and expansion mechanisms.
   • Potential Anticipation (35 U.S.C. § 102): As the immediate parent, US 10,952,723 B2 would anticipate all the claimed features in Claims 1 and 12 that were disclosed in its own specification. This would include the shells, engagement features, and the fundamental expansion mechanism using a tool-engagement surface and internal mechanics.

Summary of Anticipation:

The most relevant prior art for US patent 11864755 are its own parent and grandparent applications (US 7,704,279 B2, US 7,951,180 B2, US 9,924,940 B2, US 10,251,643 B2, and US 10,952,723 B2). These patents, all from the same family and by the same inventors, disclose substantially the same subject matter regarding expandable spinal implants, BDFT screws, and IBFDs with expanding shells and engagement features. Therefore, many if not all elements of Claims 1 and 12 of US11864755 are directly anticipated by the earlier disclosures within this patent family. The specific details of the shells, engagement features (spikes), and the various screw/gear-driven expansion mechanisms are extensively described in these prior art documents, which form the basis for the present patent.

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.