SURGICAL INSTRUMENT WITH INTEGRATED COMPRESSION AND DISTRACTION MECHANISMS

• US 20100030283A1
• Filed: 06/05/2009
• Published: 02/04/2010
• Est. Priority Date: 07/31/2008
• Status: Active Grant

• Current Assignee: Zimmer Biomet Spine, Inc. (Zimvie Incorporated)
• Original Assignee: Zimmer Spine Austin, Inc.
• Inventors: King, Emily E., Miller, Peter Thomas, Forton, Charles R., Riceman, Bruce A.
• Granted Patent: US 8,287,546 B2
• Time in Patent Office: Days
• US Class Current: 606/86.A
• CPC Class Codes: A61B 17/60 for external osteosynthesis, e.g. distractors, contractors
• CPC Class Codes: A61B 17/7032 Screws or hooks with U-shaped head or back through which longitudinal rods pass
• CPC Class Codes: A61B 17/7037 wherein pivoting is blocked when the rod is clamped
• CPC Class Codes: A61B 17/7077 for moving bone anchors attached to vertebrae, thereby displacing the vertebrae
• CPC Class Codes: A61B 17/7079 Tools requiring anchors to be already mounted on an implanted longitudinal or transverse element, e.g. where said element guides the anchor motion
• CPC Class Codes: A61B 17/708 with tubular extensions coaxially mounted on the bone anchors
• CPC Class Codes: A61B 17/7082 for driving, i.e. rotating, screws or screw parts specially adapted for spinal fixation, e.g. for driving polyaxial or tulip-headed screws driving other bone screws A61B17/8875
• CPC Class Codes: A61B 17/7091 for applying, tightening or removing longitudinal element-to-bone anchor locking elements, e.g. caps, set screws, nuts or wedges
• CPC Class Codes: A61B 2017/0256 for the spine
• CPC Class Codes: A61B 2017/681 Alignment, compression, or distraction mechanisms

Abstract

Embodiments disclosed herein provide a combination compressor/distractor useful for fitting a spinal stabilization system in a patient through minimally invasive surgery. The spinal stabilization system may comprise screws anchored in vertebrae. The vertebrae may need to be compressed or distracted. One embodiment of an instrument disclosed herein may comprise a shaft for engaging one of the screws through an extender sleeve. A driver may engage another screw through an opening of the instrument. Through this engagement, a surgeon may use the rack and pinion of the instrument to compress or distract one or more levels of the vertebrae in a parallel motion, which can be advantageous clinically in certain situations.

Claims

1. A surgical instrument, comprising:

an alignment tube constructed for receiving a driver;

a sliding bar connected to said alignment tube at a first angle, wherein a portion of said sliding bar comprises teeth;

a shaft having a threaded hole;

a pivot locking knob having a threaded end complementary to said threaded hole of said shaft; and

an elongated body having an opening constructed for accommodating said sliding bar, a gear mechanism for engaging said teeth of said sliding bar inside said elongated body, and a shaft connection mechanism for joining said shaft, said pivot locking knob, and said elongated body, wherein said shaft is movable about a pivot, wherein said shaft is lockable at a second angle relative to said elongated body utilizing said pivot locking knob, and wherein turning said gear mechanism which is engaged with said teeth of said sliding bar changes a linear distance between said shaft and said alignment tube.

2. The surgical instrument of claim 1, wherein said shaft comprises grooves constructed in a radial pattern on a surface surrounding said threaded hole.

3. The surgical instrument of claim 2, wherein said shaft connection mechanism comprises a nub having surface features complementary to said grooves in said radial pattern.

4. The surgical instrument of claim 1, wherein said shaft connection mechanism comprises a pin, a first nub having a first surface on which said pin is fixedly attached, and a second nub having an opening for receiving said threaded end of said pivot locking knob.

5. The surgical instrument of claim 1, wherein said elongated body comprises one or more windows through which said sliding bar is visible inside said elongated body.

6. The surgical instrument of claim 1, wherein said elongated body comprises a track pin, wherein said sliding bar comprises a track, and wherein said track pin and said track define a travel distance for said sliding bar relative to said elongated body.

7. The surgical instrument of claim 1, further comprising an alignment tube connection mechanism for connecting said sliding bar and said alignment tube, wherein said first angle is adjustable utilizing said alignment tube connection mechanism.

8. The surgical instrument of claim 1, wherein said second angle is adjustable utilizing said pivot locking knob.

9. The surgical instrument of claim 1, wherein said gear mechanism further comprises a circular gear for engaging said teeth of said sliding bar inside said elongated body and a tool portion for connecting said gear mechanism with a handle.

10. The surgical instrument of claim 9, wherein said elongated body further comprises a ratchet mechanism having a projection for engaging with said gear mechanism to prevent said circular gear from spinning.

11. A method for adjusting a distance between one or more levels of vertebrae, comprising:

inserting a shaft of a surgical instrument into a first extender sleeve, wherein said first extender sleeve is coupled to a first collar of a first bone fastener assembly anchored in a first vertebra, wherein said first bone fastener assembly is locked to prevent polyaxial movements, wherein said surgical instrument further comprises;

an alignment tube;

a sliding bar connected to said alignment tube at a first angle, wherein a portion of said sliding bar comprises teeth;

a pivot locking knob; and

an elongated body having an opening constructed for accommodating said sliding bar, a gear mechanism for engaging said teeth of said sliding bar, and a shaft connection mechanism for joining said shaft, said pivot locking knob, and said elongated body;

locking said shaft at a second angle relative to said elongated body utilizing said pivot locking knob;

inserting a driver through said alignment tube of said surgical instrument and into a second extender sleeve, wherein said second extender sleeve is coupled to a second collar of a second bone fastener assembly anchored in a second vertebra; and

manipulating a distance between said first vertebra and said second vertebra by moving said driver, said alignment tube, said second extender sleeve, said second bone fastener assembly, and said second vertebra in a linear motion parallel to said elongated body.

12. The method according to claim 11, wherein manipulating said distance between said first vertebra and said second vertebra further comprises:

turning said gear mechanism clockwise to increase said distance to thereby distract said first vertebra and said second vertebra;

or

turning said gear mechanism counterclockwise to decrease said distance to thereby compress said first vertebra and said second vertebra.

13. The method according to claim 11, further comprising:

adjusting said first angle;

adjusting said second angle;

or

adjusting said first angle and said second angle.

14. The method according to claim 11, further comprising:

engaging a ratchet lever with said gear mechanism to prevent said gear mechanism from turning.

15. The method according to claim 14, further comprising:

disengaging said ratchet lever from said gear mechanism.

16. A surgical system, comprising:

a first driver;

a second driver; and

a surgical instrument comprising;

an alignment tube constructed for receiving said first driver;

a sliding bar connected to said alignment tube, wherein a portion of said sliding bar comprises teeth;

a shaft having a lockable end;

a pivot locking knob having an end portion complementary to said lockable end of said shaft; and

an elongated body having an opening constructed for accommodating said sliding bar, a gear mechanism for engaging said second driver and said teeth of said sliding bar, and a shaft connection mechanism for joining said shaft, said pivot locking knob, and said elongated body, wherein said shaft is movable about a pivot, wherein said shaft is lockable at a pivot angle relative to said elongated body utilizing said pivot locking knob, and wherein turning said second driver attached to said gear mechanism which is engaged with said teeth of said sliding bar changes a linear distance between said shaft and said first driver.

17. The surgical system of claim 16, wherein said surgical instrument further comprises an alignment tube connection mechanism for connecting said sliding bar and said alignment tube.

18. The surgical system of claim 17, wherein said alignment tube connection mechanism further comprises a locking mechanism for locking said sliding bar and said alignment tube at an angle.

19. The surgical system of claim 16, wherein said elongated body of said surgical instrument further comprises a ratchet mechanism having a first portion constructed to engage with said gear mechanism and a second portion constructed to disengage from said gear mechanism.

20. The surgical system of claim 16, further comprising:

a spinal stabilization system comprising;

a first bone fastener assembly having a first collar and a first closure top;

a second bone fastener assembly having a second collar and a second closure top; and

a rod connecting said first bone fastener assembly and said second bone fastener assembly;

a first extender sleeve having a first end for receiving said shaft and a second end for coupling to said first collar of said first bone fastener assembly, wherein said first closure top locks said first bone fastener assembly relative to said rod; and

a second extender sleeve having a first end for receiving said first driver and a second end for coupling to said second collar of said second bone fastener assembly.