Spinal implantation methods utilizing a middle expandable implant

• US 5,390,683 A
• Filed: 08/20/1993
• Issued: 02/21/1995
• Est. Priority Date: 02/22/1991
• Status: Expired due to Term

• Current Assignee: Perumala Corporation
• Original Assignee: Perumala Corporation
• Inventors: Pisharodi, Madhavan
• Primary Examiner(s): Sykes, Angela D.
• Assistant Examiner(s): LACYK, JOHN P
• Application Number:
  US08/107,750
• Time in Patent Office: 550 Days
• Field of Search: 128/897-899, 606/60-75, 623/17, 602/5, 602/12, 602/18, 602/19, 602/20, 602/23, 602/32, 602/36
• US Class Current: 128/898
• CPC Class Codes: A61F 2/30744 End caps, e.g. for closing an endoprosthetic cavity
• CPC Class Codes: A61F 2/442 Intervertebral or spinal discs, e.g. resilient non-disc-shaped intervertebral inflatable pockets A61F2/441; non-disc-shaped intervertebral fusion implants A61F2/4455
• CPC Class Codes: A61F 2/4455 for the fusion of spinal bodies, e.g. intervertebral fusion of adjacent spinal bodies, e.g. fusion cages intervertebral discs A61F2/442
• CPC Class Codes: A61F 2/446 having a circular or elliptical cross-section substantially parallel to the axis of the spine, e.g. cylinders or frustocones
• CPC Class Codes: A61F 2002/2835 Bone graft implants for filling a bony defect or an endoprosthesis cavity, e.g. by synthetic material or biological material
• CPC Class Codes: A61F 2002/30092 using shape memory or superelastic materials, e.g. nitinol
• CPC Class Codes: A61F 2002/30113 circular
• CPC Class Codes: A61F 2002/30143 hexagonal
• CPC Class Codes: A61F 2002/30146 octagonal
• CPC Class Codes: A61F 2002/30153 rectangular
• CPC Class Codes: A61F 2002/30154 square
• CPC Class Codes: A61F 2002/30224 cylindrical
• CPC Class Codes: A61F 2002/30225 Flat cylinders, i.e. discs
• CPC Class Codes: A61F 2002/30235 tubular, e.g. sleeves
• CPC Class Codes: A61F 2002/30261 parallelepipedal
• CPC Class Codes: A61F 2002/3028 polyhedral different from parallelepipedal and pyramidal
• CPC Class Codes: A61F 2002/30293 Cylindrical body made by spirally rolling up a sheet or a strip around itself
• CPC Class Codes: A61F 2002/30329 Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2002/30405 made by screwing complementary threads machined on the parts themselves
• CPC Class Codes: A61F 2002/30433 using additional screws, bolts, dowels, rivets or washers e.g. connecting screws
• CPC Class Codes: A61F 2002/30451 : soldered or brazed or welded
• CPC Class Codes: A61F 2002/30507 : using a threaded locking member, e.g. a locking screw or a set screw
• CPC Class Codes: A61F 2002/30556 : for adjusting thickness
• CPC Class Codes: A61F 2002/30573 : 2-D spiral springs
• CPC Class Codes: A61F 2002/30579 : with mechanically expandable devices, e.g. fixation devices
• CPC Class Codes: A61F 2002/30594 : slotted, e.g. radial or meridian slot ending in a polar aperture, non-polar slots, horizontal or arcuate slots
• CPC Class Codes: A61F 2002/30599 : stackable
• CPC Class Codes: A61F 2002/30624 : Hinged joint, e.g. with transverse axle restricting the movement
• CPC Class Codes: A61F 2002/30777 : Oblong apertures
• CPC Class Codes: A61F 2002/30787 : inclined obliquely with respect to each other
• CPC Class Codes: A61F 2210/0014 : using shape memory or superelastic materials, e.g. nitinol
• CPC Class Codes: A61F 2220/0025 : Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2220/0041 : using additional screws, bolts, dowels or rivets, e.g. connecting screws
• CPC Class Codes: A61F 2220/0058 : soldered or brazed or welded
• CPC Class Codes: A61F 2230/0006 : circular
• CPC Class Codes: A61F 2230/0017 : Angular shapes
• CPC Class Codes: A61F 2230/0019 : rectangular
• CPC Class Codes: A61F 2230/0021 : square
• CPC Class Codes: A61F 2230/0063 : Three-dimensional shapes
• CPC Class Codes: A61F 2230/0069 : cylindrical
• CPC Class Codes: A61F 2230/0082 : parallelepipedal
• CPC Class Codes: A61F 2230/0091 : helically-coiled or spirally-coiled, i.e. having a 2-D spiral cross-section
• CPC Class Codes: A61F 2250/0009 : for adjusting thickness
• CPC Class Codes: A61F 2250/0063 : Nested prosthetic parts
• CPC Class Codes: A61F 2310/00023 : Titanium or titanium-based alloys, e.g. Ti-Ni alloys

Abstract

Artificial disk implant and methods for implanting same, the implant having a member (32, 34, 36, 77, 92, 94) for adapting in size and shape to the anatomical space between vertebrae, and apparatus (25, 42, 60, 112) for expanding the implant in the middle portion thereof to conform to the space. In one embodiment, there is provided an artificial intervertebral disk implant having a cylindrical body (20, 41, 56, 88) comprised of cylindrical subunits (32, 34, 36, 92, 94) capable of expansion. In another embodiment, rectangular members (34, 36) or elongate ribs (77) capable of expansion are provided. The implant can be used alone or in various combinations for the purpose of spinal fusion.

Claims

1. A method of maintaining the space between two adjacent vertebrae of a patient after removal of the disk from therebetween comprising the steps of:

inserting an elongate implant comprised of a central rod having two ends and an intermediate portion mounted thereto into the space between two vertebrae after removal of the disk therefrom, the implant having a length which approximates the anterior-posterior dimension of the body of the vertebrae and a vertical dimension small enough to allow the insertion of the implant;

rotating the central rod to expand the intermediate portion of the implant radially outwardly to conform the shape of the implant to the shape of the anatomical region of the disk space into which the implant is inserted; and

preventing the rotation of the central rod to prevent reversal of the outward radial expansion of the intermediate portion of the implant.

2. A method of claim 1 further comprising injecting cancellous bone chips into said disk space medial to the implant.

6. The method of claim 1 wherein expansion is accomplished by unwinding a plurality of spring-tensioned members comprising the intermediate portion of the implant, each of the members being mounted on and wound around a common longitudinal axis.

7. The method of claim 1 wherein rotation of the central rod causes first and second end caps having holes therethrough for receiving the central rod and comprising the ends of the implant to move closer together to force hinged members comprising the intermediate portion of the implant radially outwardly.

8. The method of claim 1 further comprising injecting cancellous bone chips into the disk space medial to the implant.

3. A method for fusing two adjacent vertebrae after removal of a portion of the disk from therebetween comprising the steps of:

inserting an elongate implant through an opening into a space between two adjacent vertebrae of a patient after removal of the disk from between the vertebrae, the implant having a length which approximates the anterior-posterior dimension of the body of the vertebrae and a vertical dimension small enough to allow insertion of the implant;

expanding the middle portion of the implant outwardly in a radial direction to conform the shape of the implant to the shape of the space from which the disk has been removed;

injecting cancellous bone chips into the space between the vertebrae medial to the implant; and

applying a physiologically compatible adhesive over the cancellous bone chips medial to the disk implant to close off the opening into the space from which the disk has been removed.

4. The method of claim 3 wherein expansion is accomplished by unwinding a plurality of spring-tensioned members comprising the middle portion of the implant, each of the members being mounted on and wound around a common longitudinal axis.

5. The method of claim 3 wherein expansion is accomplished by rotating a central rod, causing first and second end caps having holes therethrough for receiving the rod to move closer together to force hinged members comprising the middle portion of the implant radially outwardly.

9. A method of maintaining the space between two adjacent vertebrae of a patient after removal of a portion of the disk from therebetween comprising the steps of:

inserting an elongate implant into the space between two vertebrae after removal of a portion of the disk therefrom, the implant having a length which approximates the anterior-posterior dimension of the body of the vertebrae and a vertical dimension small enough to allow the insertion of the implant;

expanding the implant radially outwardly in the portion intermediate the ends thereof by rotating a central rod, causing first and second end caps having holes therethrough for receiving the rod to move closer together to force hinged members comprising the intermediate portion of the implant radially outwardly, to conform the shape of the implant to the shape of the anatomical region of the disk space into which the implant is inserted; and

preventing the reversal of the outward radial expansion of the intermediate portion of the implant.

10. A method of stabilizing the spine of a patient comprising the steps of:

removing a portion of an intervertebral disk of the patient;

inserting an elongate implant into the space between the vertebrae from which the portion of the intervertebral disk has been removed and off center relative to the bodies of the adjacent vertebrae, the implant having a length which approximates the anterior-posterior dimension of the bodies of the vertebrae and a vertical dimension small enough to allow insertion of the implant through the gap between the vertebrae and adjacent the dorsal spine thereof;

expanding the middle portion of the implant outwardly in a radial direction to conform the shape of the implant to the shape of the space from which the portion of the intervertebral disk was removed; and

injecting cancellous bone chips into the space between the vertebrae and medial to the implant.

11. The method of claim 10 further comprising applying a physiologically compatible adhesive over the cancellous bone chips to close off the gap through which the implant was inserted.