Artificial vertebral body

• US 5,290,312 A
• Filed: 09/03/1991
• Issued: 03/01/1994
• Est. Priority Date: 09/03/1991
• Status: Expired due to Term

• Current Assignee: Alphatec Spine Incorporated (Alphatec Holdings Incorporated)
• Original Assignee: Alphatec
• Inventors: Kojimoto, Haruo, Yasui, Natsuo
• Primary Examiner(s): Isabella, David
• Assistant Examiner(s): BRITTINGHAM, DEBRA
• Application Number:
  US07/753,786
• Time in Patent Office: 910 Days
• Field of Search: 623/17, 606/61, 606/62, 606/63, 606/64, 606/60
• US Class Current: 623/17.15
• CPC Class Codes: A61B 17/86 Pins or screws or threaded wires; nuts therefor A61B17/72 take precedence
• CPC Class Codes: A61F 2/44 for the spine, e.g. vertebrae, spinal discs
• CPC Class Codes: A61F 2002/30154 square
• CPC Class Codes: A61F 2002/30261 parallelepipedal
• CPC Class Codes: A61F 2002/30367 with additional means for preventing said rotation
• CPC Class Codes: A61F 2002/3037 Translation along the common longitudinal axis, e.g. piston
• CPC Class Codes: A61F 2002/30373 with additional means for preventing said translation
• CPC Class Codes: A61F 2002/30507 using a threaded locking member, e.g. a locking screw or a set screw
• CPC Class Codes: A61F 2002/3055 for adjusting length
• CPC Class Codes: A61F 2002/30593 hollow
• CPC Class Codes: A61F 2002/30601 telescopic
• CPC Class Codes: A61F 2002/30774 internally-threaded
• CPC Class Codes: A61F 2002/4631 the prosthesis being specially adapted for being cemented
• CPC Class Codes: A61F 2220/0025 Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2220/0033 made by longitudinally pushing a protrusion into a complementary-shaped recess, e.g. held by friction fit
• CPC Class Codes: A61F 2230/0021 square
• CPC Class Codes: A61F 2230/0082 parallelepipedal
• CPC Class Codes: A61F 2310/00017 Iron- or Fe-based alloys, e.g. stainless steel
• CPC Class Codes: A61F 2310/00023 Titanium or titanium-based alloys, e.g. Ti-Ni alloys
• CPC Class Codes: A61F 2310/00179 Ceramics or ceramic-like structures
• CPC Class Codes: Y10S 606/907 : Composed of particular material or coated

Abstract

A prosthetic vertebra has a first hollow parallelepiped-shaped component and a second component shaped identically to the first component and marginally smaller than the first component. The second component can accordingly be positioned partially within the first component and can be axially moved within the first component, so that the overall length of the prosthetic vertebra can be established by appropriately moving the second component within the first. A set screw is threadably engageable with the first component and can be tightened against the second component to hold the components axially stationary relative to each other, once the prosthetic vertebra has been positioned in the patient and its length adjusted as appropriate to fit the patient.

Claims

1. An implantable artificial vertebra which is biocompatible and sized for replacing a metastatic vertebra, comprising:

a first hollow component having an abutting end for abutting a vertebra of a living being and an anchoring window formed in said abutting end, an open first side establishing an access window, and an open end formed opposite said abutting end;

a second hollow component having a second abutting end for abutting a vertebra of a living being and a second anchoring window formed in said second abutting end, an open first side establishing a second access window, and a second open end formed opposite said second abutting end, the second component being slidably receivable through the open end of said first component; and

motion preventing means engageable with both of said components for substantially preventing slidable motion between said components.

2. The artificial vertebra recited in claim 1, wherein each component is shaped generally as an elongated parallelepiped.

3. The artificial vertebra recited in claim 2, wherein each abutting end includes an abutting end surface for abutting a vertebra of a living being, and each anchoring window is formed in its respective abutting end to establish a passageway through the abutting end surface for infusing bone cement therethrough.

4. The artificial vertebra recited in claim 3, wherein each component has four sides, said first side of each component having an access window formed therein, each first side comprising a lip surrounding a portion of said access window, the other three sides of each component being closed to form a chamber within each component.

5. The artificial vertebra recited in claim 4, wherein said motion preventing means includes a screw, and said lip of said first component has a hole formed therein for receiving said screw, said screw being threadably engageable with said hole to abut said second component and hold said second component stationary with respect to said screw.

6. The artificial vertebra recited in claim 5, wherein said second component has a channel formed therein, said channel having a tapered bottom wall, said screw being engageable with said hole in said first component to abut said channel.

7. The artificial vertebra recited in claim 1, further 10 comprising anchoring means engageable with each said component to attach each component to a vertebra of a living being.

8. The artificial vertebra recited in claim 7, wherein said anchoring means for each component includes a bolt and flange formed on the abutting end surface of said component, said flange having an aperture formed therethrough, said bolt being engageable with said aperture and the vertebra of the living being to hold said component against the vertebra.

9. The artificial vertebra recited in claim 8, wherein each component defines a longitudinal axis extending through said abutting end and said open end, and said aperture has a longitudinal axis, said aperture being formed in said flange with the axis of said aperture establishing an oblique angle with the axis of said component.

10. A method for replacing a metastatic vertebra located between a first and a second vertebra of a patient, comprising;

removing the metastatic vertebra from the patient;

providing a first hollow component having an abutting end for abutting a vertebra of a living being and an anchoring window formed in said abutting end, an open first side establishing an access window, and an open end formed opposite said abutting end;

providing a second hollow component having an abutting end, said second abutting end for abutting a vertebra of a living being and a second anchoring window formed in said second abutting end, an open first side establishing a second access window, and a second open end formed opposite said second abutting end, said components being slidably engaged with each other to establish an implantable artificial vertebra which is biocompatible and having an adjustable length;

positioning said artificial vertebra between said first and second vertebrae;

sliding the first hollow component relative to the second hollow component to establish the length of the artificial vertebra to be substantially equal to a predetermined distance between the first and second vertebrae;

preventing relative motion between the first and second components; and

respectively connecting the first and second components to the first and second vertebrae.

11. The method of claim 10, wherein each component is shaped generally as an elongated parallelepiped, wherein the second component is slidably receivable through the open end of said first component.

12. The method of claim 11, wherein each component forms a chamber and the abutting end of each component includes an abutting end surface for abutting a vertebra, and each anchoring window is formed in its respective abutting end to establish a passageway through the abutting end surface to the chamber.

13. The method of claim 12, wherein said connecting step comprises infusing bone cement into the access window of each component to fill each chamber and to flow through the anchoring windows and onto the first and second vertebrae.

14. The method of claim 13, wherein said connecting step further comprises:

engaging a bolt with each component and the bone cement to hold the component against the vertebra.

15. An artificial implantable vertebra which is biocompatible and positionable between a first and second vertebra to establish a predetermined distance therebetween, comprising:

a first and a second hollow component, each component generally shaped as an elongated parallelepiped having an open end and abutting end having an abutting end surface for abutting an associated vertebra and an anchoring window formed in said abutting end surface, each component having first, second, and third closed sides and an open side having an access window formed therein, said access window being bounded by a lip, and the second component being slidably receivable through the open end of the first component to establish an adjustable length of the artificial vertebra;

a hole formed in the lip of the open side of the first component;

a screw engageable with said hole to abut said second component to hold said second component stationary with respect to said first component and thereby establish a predetermined length for said artificial vertebra, said predetermined length being established to be approximately equal to the predetermined distance between the first and second vertebrae;

an aperture formed in the abutting end surface of each component; and

a bolt engageable with each aperture and the associated vertebra to hold the component against the vertebra.