Method and device for surgical bone grinding
DCFirst Claim
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1. A bone grinder, comprising:
- a housing having a bone chute therethrough and a chamber intersecting said bone chute, wherein said bone chute has a bone segment entry portion for receiving bone segments, and an exit opening for exiting bone fragments of a predetermined size produced from said received bone segments;
a grinding assembly provided in said chamber, said grinding assembly rotatable about an axis traversing an extent of said bone chute, wherein said grinding assembly includes;
(a) a shaft rotatable about said axis, and (b) a plurality of cutting plates, each plate having opposed first and second sides, a corresponding thickness therebetween and an opening through said thickness of the plates between said opposed sides for matingly receiving said shaft, and at least one cutting edge between said opposed sides for fragmenting said bone segments within said entry portion when said cutting plate rotates with said shaft;
wherein at least two of said cutting plates are adjacent on said shaft so that for said adjacent cutting plates;
(c) said at least one cutting edge on each of said adjacent cutting plates have contiguous cutting paths, and, (d) said at least one cutting edge on both of said adjacent cutting plates are oriented in a same direction for fragmenting said bone segments.
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Abstract
A method and apparatus for grinding bone for use in orthopaedic procedures includes a bone shoot for receiving bone segments which are fed into a grinding assembly rotatable about an axis such that a plurality of cutting plates rotate about such axis to grind bone into uniform and desirable sized portions suitable for use in cementing of bone implants.
27 Citations
34 Claims
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1. A bone grinder, comprising:
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a housing having a bone chute therethrough and a chamber intersecting said bone chute, wherein said bone chute has a bone segment entry portion for receiving bone segments, and an exit opening for exiting bone fragments of a predetermined size produced from said received bone segments;
a grinding assembly provided in said chamber, said grinding assembly rotatable about an axis traversing an extent of said bone chute, wherein said grinding assembly includes;
(a) a shaft rotatable about said axis, and (b) a plurality of cutting plates, each plate having opposed first and second sides, a corresponding thickness therebetween and an opening through said thickness of the plates between said opposed sides for matingly receiving said shaft, and at least one cutting edge between said opposed sides for fragmenting said bone segments within said entry portion when said cutting plate rotates with said shaft;
wherein at least two of said cutting plates are adjacent on said shaft so that for said adjacent cutting plates;
(c) said at least one cutting edge on each of said adjacent cutting plates have contiguous cutting paths, and, (d) said at least one cutting edge on both of said adjacent cutting plates are oriented in a same direction for fragmenting said bone segments. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
wherein for a consecutive two of said cutting edges, E1 and E2, said leading face (L2) for E2 is therebetween, and the following conditions hold;
(i) L2 includes a concave portion of said rim;
(ii) a radius from a center of said at least one cutting plate to E2 is substantially tangent to L2;
(iii) for C being a maximal non-concave curvature of said rim between E1 and L2, and for a portion P on said rim between E1 and L2 wherein said rim has said maximal non-concave curvature C at P, then from P to E1, said rim has no concave portion that has a curvature greater than or equal to C.
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10. The bone grinder of claim 9, wherein E1 has a contiguous trailing portion of said rim, and said trailing portion is substantially planar.
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11. The bone grinder of claim 9, wherein said curvature C is less than a curvature of L2.
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12. The bone grinder of claim 9, wherein no portion of L2 is on a trailing side of the radius from the center of said at least one cutting plate to E2.
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13. The bone grinder of claim 9, wherein L2 is entirely non-convex.
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14. The bone grinder of claim 13, wherein L2 contacts the radius from the center of said at least one cutting plate to E2 at at most E2.
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15. The bone grinder of claim 9, wherein there is a smooth transition from L2 to E1, wherein a maximal curvature corresponds to a radius of approximately 0.046 inches.
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16. The bone grinder of claim 9, wherein an angle greater than 50 degrees is between:
- (a) a radius from a center of said at least one cutting plate to E2, and (b) a trailing portion of said rim that is contiguous to and trails the cutting edge E2 when said at least one cutting plate rotates.
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17. The bone grinder of claim 9, wherein said corresponding thickness of said at least one cutting plate and a height of a cutting tooth including E1 have relative proportions to one another so as to separate bone fragments from the bone segments that are approximately a same size as said thickness of said at least one cutting plate.
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18. The bone grinder of claim 17, wherein said size is in a range from approximately ⅛
- inch to approximately ¼
inch.
- inch to approximately ¼
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19. The bone grinder of claim 17, wherein said corresponding thickness of said at least one cutting plate and said height of said cutting tooth are substantially equal.
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20. The bone grinder of claim 1, wherein at least one of said cutting plates has a hardness in a range of 52 to 56 Rockwell.
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21. The bone grinder of claim 1, wherein at least one of said cutting plates is composed of 4-40C stainless steel.
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22. The bone grinder of claim 21, wherein said 4-40C stainless steel is double drawn.
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23. The bone grinder of claim 1, wherein for each cutting plate C1 of at least most of said cutting plates, there is one of said cutting plates C2, wherein C1 and C2 have contiguous cutting paths, and C1 includes a plurality of said cutting edges and said plurality of cutting edges are oriented in a same direction for cutting into said bone fragments as C2.
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24. The bone grinder of claim 23, wherein said plurality of said cutting edges of C1 are distributed substantially uniformly about a rim of C1.
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25. The bone grinder of claim 1 further including a gear box and a crank arm for manually rotating said shaft, wherein said gear box provides a gear reduction in a range of 2:
- 1 to 4;
1.
- 1 to 4;
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26. The bone grinder of claim 1, wherein said housing and said grinding assembly are included in a hand-held assembly also including a handle, wherein said hand-held assembly is manually detachable from a base, and wherein said hand-held assembly is operable for grinding bone whether detached from said base or attached to said base.
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27. The bone grinder of claim 26 further including a plunger and an operably connected linkage are used to force the bone segments toward and into contact with said grinding assembly, wherein said linkage is also connected to a grip portion for transferring pressure from said grip portion being manually gripped to a force for forcing the bone segments toward and into contact with said grinding assembly.
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28. The bone grinder of claim 1, wherein said handle is oriented at approximately 30°
- to 60°
from horizontal when said hand-held assembly is operably attached to said base for grinding bone.
- to 60°
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29. The bone grinder of claim 1, wherein for a first of said cutting plates, said first cutting plate is manually replaceable by another cutting plate, wherein said another cutting plate is matingly provided on said shaft in an operable grinding arrangement with at least a second of said cutting plates that was previously matingly received on said shaft with said first cutting plate.
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30. A bone grinder, comprising:
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a bone chute having an entry portion for receiving bone segments, and an exit opening for exiting bone fragments of a preferred size produced from said received bone segments;
a grinding assembly provided in said chamber, said grinding assembly rotatable about an axis traversing an extent of said bone chute, wherein said grinding assembly includes;
(a) a shaft rotatable about said axis, and (b) at least one cutting plate having a rim with a plurality of cutting edges thereon for cutting fragments of said bone segments within said entry portion when said at least one cutting plate rotates with said shaft;
wherein for a consecutive two of said cutting edges, E1 and E2, there is a leading face (L2) for E2 therebetween, wherein L2 is contiguous to E2, and L2 leads E2 when said cutting plate rotates for grinding; and
wherein the following conditions (i) through (iv) hold;
(i) L2 is non-convex, and includes a concave portion of said rim, wherein said concave portion is contiguous to E2;
(ii) substantially all of L2 is on a side, S, of a radius from a center of said cutting plate to E2, wherein S leads E2 when said cutting plate rotates for grinding;
(iii) for C being a maximal non-concave curvature of said rim between E1 and L2, and for a portion P on said rim between E1 and L2, wherein said rim has said maximal non-concave curvature C at P, then from P to E1, said rim has no concave portion that has a curvature greater than or equal to C;
(iv) said curvature C is less than a curvature of said concave portion of L2. - View Dependent Claims (31)
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32. A bone grinder, comprising:
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a housing having a bone chute therethrough and a chamber intersecting said bone chute, wherein said bone chute has a bone segment entry portion for receiving bone segments, and an exit opening for exiting bone fragments of a predetermined size produced from said received bone segments;
a grinding assembly provided in said chamber, said grinding assembly rotatable about an axis traversing an extent of said bone chute, wherein said grinding assembly includes;
(a) a shaft rotatable about said axis, and (b) a plurality of cutting plates, each plate having opposed first and second sides, a corresponding thickness therebetween and an opening through said thickness of the plates between said opposed sides for matingly receiving said shaft, and at least one cutting edge between said opposed sides for fragmenting said bone segments within said entry portion when said cutting plate rotates with said shaft;
wherein at least two of said cutting plates are adjacent on said shaft so that for said adjacent cutting plates (c) said at least one cutting edge on each of said adjacent cutting plates provides a contiguous cutting path with said at least one cutting edge on the other of said adjacent cutting plates, and, and (d) said at least one cutting edge on both of said adjacent cutting plates are oriented in a same direction for fragmenting said bone segments.
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33. A method for grinding bone, comprising:
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providing a housing having a bone chute therethrough and a chamber intersecting said bone chute, wherein said bone chute has a bone segment entry portion for receiving bone segments, and an exit opening for exiting bone fragments of a predetermined size produced from said received bone segments;
providing a grinding assembly provided in said chamber, said grinding assembly rotatable about an axis traversing an extent of said bone chute, wherein said grinding assembly includes;
(a) a shaft rotatable about said axis, and (b) a plurality of cutting plates, each plate having opposed first and second sides, a corresponding thickness therebetween and an opening through said thickness of the plates between said opposed sides for matingly receiving said shaft, and at least one cutting edge between said opposed sides for fragmenting said bone segments within said entry portion when said cutting plate rotates with said shaft;
wherein at least two of said cutting plates are adjacent on said shaft so that for said adjacent cutting plates;
(c) said at least one cutting edge on each of said adjacent cutting plates have contiguous cutting paths in said bone chute;
(d) said at least one cutting edge on both of said adjacent cutting plates are oriented in a same direction for fragmenting said bone segments; and
(e) grinding bone by placing said bone segments in said bone chute. - View Dependent Claims (34)
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Specification