Interspinous, interlaminar space expander and measurement instrument
An interspinous, interlaminar space expander and measurement instrument for preparing an interspinous, interlaminar space between adjacent vertebrae to receive an implantable interspinous, interlaminar stabilization device is provided. The instrument includes an indicator which measures both height of the space and applied force to maintain that height.
1. An instrument for evaluating an interspinous, interlaminar space between adjacent vertebrae, comprising:
a pair of handles connected at a pivoting hinge, each handle having a gripping portion at one end and extending into a leg extension at another, each of the leg extensions terminating at a tip having a bearing surface for engaging a bone surface, wherein the tip of each leg extension extends at an angle less than 180 degrees relative to the leg extensions,
a spring bias mechanism between the pair of handles, and
a combination distance and force measurement component in cooperation with the pair of handles, the component being configured to measure a distance of the interspinous, interlaminar space, and a force for maintaining said distance, wherein the combination distance and force measurement component includes a single main body coupled to at least one of the pair of handles, the main body including at one portion thereof a series of indicia representing units of distance and, at another portion thereof, a series of indicia representing units of force.
2. The instrument of claim 1 , wherein each of the leg extensions extends at an angle relative to the handles in at least first and second intersecting planes.
3. The instrument of claim 2 , wherein each of the leg extensions extends at a right angle relative to the handles in each of the first and second intersecting planes.
4. The instrument of claim 1 , wherein the tips extend at a right angle relative to the leg extensions.
5. The instrument of claim 1 , wherein the bearing surface includes a surface feature for enhanced bone contact.
6. The instrument of claim 1 , wherein the spring bias mechanism comprises a pair of interconnected leaf springs.
7. The instrument of claim 1 , wherein the combination distance and force measurement component is slidingly attached to one of the handles and fixedly attached to the other of the handles.
8. The instrument of claim 1 , wherein the combination distance and force measurement component main body has a channel and a translatable shaft movable therein.
9. The instrument of claim 8 , further including a knob for maintaining the handles in position relative to one another against the translatable shaft of the combination distance and force measurement component.
10. The instrument of claim 8 , wherein the translatable shaft includes a band to indicate a measured unit of distance when viewed through a window of the main body near the indicia representing units of distance.
11. The instrument of claim 8 , further including a pointer extending from one of the handles for resting against the main body near the series of indicia representing units of distance.
12. The instrument of claim 1 , wherein movement of the gripping portion of the handles towards one another effects spreading apart of the tips.
13. The instrument of claim 1 , wherein the units of distance are millimeters.
14. The instrument of claim 1 , wherein the distance measured represents a height of the interspinous, interlaminar space between the adjacent vertebrae.
15. The instrument of claim 1 , wherein the units of force are Newtons.
16. The instrument of claim 1 , wherein the force measured represents an amount of tension between the adjacent vertebrae.
17. The instrument of claim 1 , wherein the angle between each tip and each leg extension is in the range of about 60 to 120 degrees.
18. The instrument of claim 1 , wherein the angle between each tip and each leg extension is in the range of about 75 to 105 degrees.
19. The instrument of claim 1 , wherein the leg extensions and the tips are configured to bear a load.
20. An instrument for evaluating an interspinous, interlaminar space between adjacent vertebrae, comprising:
a pair of handles connected at a pivoting hinge, each handle having a gripping portion at one end and extending into a leg extension at another, each of the leg extensions terminating at a tip having a bearing surface for engaging a bone surface,
a spring bias mechanism between the pair of handles, and
a combination distance and force measurement component in cooperation with the pair of handles, the component being configured to measure a distance of the interspinous, interlaminar space, and a force for maintaining said distance, the combination distance and force measurement component including a single main body coupled to at least one of the pair of handles, the main body including at one portion thereof a series of indicia representing units of distance and, at another portion thereof, a series of indicia representing units of force;
wherein the leg extensions extend at an angle relative to the handles in at least first and second intersecting planes.