Spinal column fixation device

• US 4,950,269 A
• Filed: 06/13/1988
• Issued: 08/21/1990
• Est. Priority Date: 06/13/1988
• Status: Expired due to Fees

• Current Assignee: AcroMed Corp (Johnson & Johnson)
• Original Assignee: AcroMed Corp (Johnson & Johnson)
• Inventors: Gaines, Robert W. Jr.
• Primary Examiner(s): Apley, Richard J.
• Assistant Examiner(s): NOT, DEFINED
• Application Number:
  US07/206,007
• Time in Patent Office: 799 Days
• Field of Search: 128/92 Z, 128/92 ZZ, 128/92 ZW, 128/92 ZY, 128/92 YV, 128/92 YF, 128/92 YE, 128/92 YM, 128/69, 128/75, 128/83, 403/354, 403/359, 403/397-399, 403/395, 403/344, 248/71, 248/74.1, 248/74.2, 248/73, 248/74, 248/3, 248/316.7, 248/74.4, 248/62, 248/65, 24/459, 24/542, 24/462, 24/486, 411/355, 411/362, 411/363, 411/373, 411/375, 411/522, 411/523, 411/529, 606/60, 606/61, 606/62, 606/65, 606/72
• US Class Current: 606/261
• CPC Class Codes: A61B 17/7004 with a cross-section which varies along its length A61B17/7019 takes precedence
• CPC Class Codes: A61B 17/7005 Parts of the longitudinal elements, e.g. their ends, being specially adapted to fit in the screw or hook heads
• CPC Class Codes: A61B 17/7032 Screws or hooks with U-shaped head or back through which longitudinal rods pass

Abstract

An apparatus for connecting vertebrae including a rod and a fastener for connecting the rod with a vertebra of a spinal column. The fastener includes a screw having a threaded portion for connection with the vertebra. The screw has a head connected to one end of the threaded portion. The head includes a bight portion and a pair of spaced apart resiliently deflectable legs extending from the bight portion. The pair of legs and the bight portion define a cavity in the screw head. The rod is receivable in the cavity in the screw head. A cap is receivable on the pair of legs and deflects the pair of legs to clamp around the portion of the rod received in the cavity in the screw head. The cap is retained on the screw so that movement of the rod relative to the screw is blocked.

Claims

1. A spiral column fixation device comprising:

a bio-compatible screw including a threaded portion for connection with a vertebra of a spinal column, a bight portion fixed to said threaded portion and a pair of spaced apart resiliently deflectable legs extending from said bight portion, said pair of legs and said bight portion having surfaces defining a cavity in said screw;

a rod sized for connection with the spiral column of a patient including a portion receivable in the cavity in said screw;

a cap receivable on said pair of legs of said screw;

means for retaining said cap on said screw to block movement of said rod from the cavity in said screw; and

wherein the fixation device is of a size and shape adapted for use with the spinal column of a patient.

2. The spinal column fixation device set forth in claim 1 wherein said retaining means includes surface means defining a cavity in said cap and a projection extending transversely from one of said pair of legs, said projection being receivable in the cavity in said cap to block movement of said cap relative to said screw in a direction substantially parallel to the direction in which said one of said pair of legs extends.

3. The spinal column fixation device set forth in claim 1 wherein said retaining means includes surface means defining a recess in said cap for receiving a portion of one of said pair of legs to block movement of said cap relative to said screw in a direction substantially parallel to the direction said rod extends when said rod is received in the cavity in said screw.

4. The spinal column fixation device set forth in claim 1 further including means for deflecting at least one of said pair of legs to clamp said portion of said rod between said pair of legs and said bight portion to block relative movement between said rod and said screw.

5. A spinal column fixation device comprising:

a bio-compatible screw including a threaded portion for connection with a vertebra, a bight portion fixed to said threaded portion and a pair of spaced apart resiliently deflectable legs extending from said bight portion, said pair of legs and said bight portion having surfaces defining a cavity in said screw;

a rod including a portion receivable in the cavity in said screw;

means for deflecting at least one of said pair of legs to clamp said portion of said rod between said pair of legs and said bight portion to block relative movement between said rod and said screw; and

wherein the fixation device is of a size and shape adapted for use with the spinal column of a patient.

6. A spinal column fixation device set forth in claim 5 wherein said deflecting means includes a cap having surface means defining a cavity in said cap for receiving said pair of legs and a pair of projections, each of said projections extending transversely from a respective one of said pair of legs in a direction away from one another, said surface means defining the cavity in said cap having a width less than the width between the outermost extent of said projections for pressing said pair of legs relatively toward one another when said projections are received in the cavity in said cap.

7. A spinal column fixation device set forth in claim 6 wherein each of said projections includes a cam surface and said cap includes surfaces for engaging a respective one of said cam surfaces to expand said cap over said projections and deflect said pair of legs relatively toward one another from an initial free state position as said cap is moved to a first position relatively toward said bight portion of said screw, said projections being received in the cavity in said cap when said cap is moved to a second position from the first position in a direction further toward said bight portion of said screw to block movement of said cap relative to said screw in a direction substantially parallel to the direction in which said pair of legs extend.

8. The spinal column fixation device comprising:

an elongate rod including a first portion having a cross section taken in a plane extending perpendicular to the longitudinal central axis of said rod of a first width and a second portion axially adjacent said first portion and having a cross section taken in a plane extending perpendicular to the longitudinal central axis of said rod of a second width greater than said first width so said first portion defines a recess in said rod;

a bio-compatible screw including a threaded portion for connection with a vertebra and a head integral with to said threaded portion, said head including surface means defining a cavity for receiving said first portion of said rod;

means for blocking movement of said first portion of said rod relative to said head of said screw in a direction transverse to the longitudinal central axis of said rod when said rod is received in said cavity in said screw;

a portion of said surface means defining the cavity in said head of said screw being extendable into the recess in said rod and being engageable with said second portion of said rod to block movement of said rod relative to said fastener in a direction parallel to the longitudinal central axis of said rod; and

wherein the fixation device is of a size and shape adapted for use with the spinal column of a patient.

9. The spinal column fixation device set forth in claim 8 wherein said blocking means includes a cap having surface means defining a cavity in said cap for receiving a portion of said head of said screw and means for retaining said cap on said head of said screw.

10. The spinal column fixation device set forth in claim 9 wherein said retaining means includes surface means defining a recess in said cap for receiving a portion of said head to block movement of said cap relative to said screw in a direction substantially parallel to the direction said rod extends when said rod is received in the cavity in said screw.

11. The spinal column fixation device set forth in claim 8 further including means for deflecting a portion of said head of said screw to clamp said first portion of said rod to block movement of said rod relative to said screw.

12. An apparatus comprising:

a screw including a threaded portion for connection with a vertebra of a spinal column, a bight portion fixed to said threaded portion and a pair of spaced apart resiliently deflectable legs extending from said bight portion, said pair of legs and said bight portion having surfaces defining a cavity in said screw;

a rod including a portion receivable in the cavity in said screw;

a cap receivable on said pair of legs of said screw; and

means for retaining said cap on said screw to block movement of said rod from the cavity in said screw, wherein said rod includes a first portion with a cross section in a plane extending perpendicular to the longitudinal central axis of said rod of a first width and a second portion with a cross section in a plane extending perpendicular to the longitudinal central axis of said rod of a second width greater than said first width, said first portion being receivable in the cavity in said screw and defining a recess in said rod, and said retaining means further includes a projection on said screw extending into the cavity in said screw and into the recess in said rod for engaging said second portion of said rod to block movement of said rod relative to said screw in a direction substantially parallel to the longitudinal central axis of said rod.

13. An apparatus comprising:

a screw including a threaded portion for connection with a vertebra, a bight portion fixed to said threaded portion and a pair of spaced apart resiliently deflectable legs extending from said bight portion, said pair of legs and said bight portion having surfaces defining a cavity in said screw;

a rod including a portion receivable in the cavity in said screw; and

means for deflecting at least one of said pair of legs to clamp said portion of said rod between said pair of legs and said bight portion to block relative movement between said rod and said screw, including a cap having surface means defining a cavity in said cap for receiving said pair of legs and a pair of projections, each of said projections extending transversely from a respective one of said pair of legs in a direction away from one another, said surface means defining the cavity in said cap having a width less than the width between the outermost extent of said projections for pressing said pair of legs relatively toward one another when said projections are received in the cavity in said cap, said cap further including surface means defining a recess in said cap for receiving a portion of one of said pair of legs to block movement of said cap relative to said screw in a direction substantially parallel to the direction that said rod extends when said rod is received in the cavity in said screw.

14. An apparatus comprising:

an elongate rod including a first portion having a cross section taken in a plane extending perpendicular to the longitudinal central axis of said rod of a first width and a second portion axially adjacent said first portion and having a cross section taken in a plane extending perpendicular to the longitudinal central axis of said rod of a second width greater than said first width so said first portion defines a recess in said rod;

a screw including a threaded portion for connection with a vertebra and a head fixed to said threaded portion, said head including surface means defining a cavity for receiving said first portion of said rod;

means for blocking movement of said first portion of said rod relative to said head of said screw in a direction transverse to the longitudinal central axis of said rod when said rod is received in said cavity in said screw; and

a portion of said surface means defining the cavity in said head of said screw being extendable into the recess in said rod and being engageable with said second portion of said rod to block movement of said rod relative to said fastener in a direction parallel to the longitudinal central axis of said rod;

wherein said blocking means includes a cap having surface means defining a cavity in said cap for receiving a portion of said head of said screw and means for retaining said cap on said head of said screw, and said retaining means includes a projection extending transversely from said head and being receivable in the cavity in said cap to block movement of said cap relative to said screw in a direction transverse to the direction in which said rod extends when said rod is received in the cavity in the head.