Surgical instrument for cone-shaped sub-trochanteric rotational osteotomy

• US 5,409,489 A
• Filed: 01/12/1993
• Issued: 04/25/1995
• Est. Priority Date: 01/12/1993
• Status: Expired due to Fees

• Current Assignee: Georges Sioufi
• Original Assignee: Georges Sioufi
• Inventors: Sioufi, Georges
• Primary Examiner(s): Brown, Michael A.
• Application Number:
  US08/003,507
• Time in Patent Office: 833 Days
• Field of Search: 606/61, 606/62, 606/79-80, 606/86, 606/87, 606/88, 606/96, 606/97, 606/98, 606/102, 606/104
• US Class Current: 606/80
• CPC Class Codes: A61B 17/1604 Chisels; Rongeurs; Punches; Stamps
• CPC Class Codes: A61B 17/1668 for the upper femur A61B17/164 takes precedence
• CPC Class Codes: A61B 17/1721 for applying pins along or parallel to the axis of the femoral neck
• CPC Class Codes: A61B 17/1732 for bone breaking devices
• CPC Class Codes: A61B 17/746 the longitudinal elements coupled to a plate opposite the femoral head

Abstract

A surgical instrument and kit including it, for use to carry out a cone-shaped sub trochanteric rotational osteotomy. The instrument has a guide that is fixed to a cervical screw which has been previously inserted into the femoral head along the axis of the cone to be cut. A drill bit driven in rotation about its own axis passes through the guide in an oblique hole extending at an angle equal to half the angle of the cone to be cut. The drill bit penetrates the lateral wall of the femur as close as possible to the cervical screw. Cutting of the cone is achieved by lateral displacement of the drill bit in a circular motion, which is progressively enlarged as the bit moves forward. In addition to the instrument, the kit contains a chisel with cutting wings, which is insertable in the cervical screw to allow the wings to make slits in the bone. Once the bone is cut and the guide and drill bit have been removed, the ill weight-bearing zone of the patient'"'"'s femoral head is rotated and replaced by a healthy zone of the femoral head. This kit also has a compression plate which is insertable on the cervical screw and simultaneously in the slits done by the cutting wings of the chisel. This compression plate is used to fasten the femoral head to the femur in its new position.

Claims

1. A surgical instrument for use to make a cut shaped as a cone in the proximal femur of a patient, said cone having a tip located on the postero lateral side at the sub-trochanteric level, a base located at the trans-trochanteric level and a central axis aligned with the axis of the femoral neck, all in the aim of reorienting at a given degree the femoral head in the acetabulum in a rotational fashion depending on the need of the patient, so as to transfer an ill zone in said femoral head from a weight bearing zone to a non-weight bearing zone, said instrument comprising:

a) a cutting guide attachable to a hollowed cervical screw previously inserted into the femoral head along the central axis of the cone to be cut, said guide, once fastened, being free to rotate relative to said cervical screw around the axis of said cervical screw;

b) a drilling bit passing through said guide in an oblique hole having a slope which corresponds to half the angle of the cone to be cut, in order to penetrate the bone at the level of the lateral wall of the femur as close as possible to said cervical screw and thus cut the cone by lateral displacement of the bit in a circular motion which is progressively enlarged as the drill bit moves forward in the femur head, thus initiating cutting of the cone from its tip to its base; and

c) means to connect the drill bit on the guide to drive it in rotation about its own axis, said means being also devised to allow the bit to be moved forward while it is rotated about the axis of the cervical screw,

wherein said means to connect said drill bit and drive it in rotation includes a rectilinear sliding system comprising an adjustment screw with a large number of threads per unit of length, for advancing said bit along its own axis.

2. An instrument as defined in claim 1, wherein said means to connect said drill bit and drive it in rotation also includes a supporting arm attachable to said guide to keep said bit in alignment with said oblique hole.

3. An instrument as defined in claim 2, wherein means to connect said drill bit and drive it in rotation also includes a turbine.

4. An instrument as defined in claim 3, wherein said guide includes at least four of said oblique holes each with a different slope, said slopes ranging between 25°

and 35°

, and wherein said means to connect said drill bit and drive it in rotation are so devised as to allow said drill bit to pass into any one of said four oblique holes to as to extend at the angle of the corresponding slope.

5. An instrument as defined in claim 2, wherein said guide includes at least four of said oblique hole each with a different slope, said slopes ranging between 25°

and 35°

, and wherein said means to connect said drill bit and drive it in rotation are so devised as to allow said drill bit to pass into any one of said four oblique holes to as to extend at the angle of the corresponding slope.

6. An instrument as defined in claim 1, wherein said guide has a detachable handle which allows said guide to be turned around itself about the axis of said cervical screw.

7. An instrument as defined in claim 1, wherein means to connect said drill bit and drive it in rotation also includes a turbine.

8. An instrument as defined in claim 7, wherein said guide includes at least four of said oblique hole each with a different slope, said slopes ranging between 25°

and 35°

, and wherein said means to connect said drill bit and drive it in rotation are so devised as to allow said drill bit to pass into any one of said four oblique holes to as to extend at the angle of the corresponding slope.

9. An instrument as defined in claim 1, wherein said guide includes at least four of said oblique hole each with a different slope, said slopes ranging between 25°

and 35°

, and wherein said means to connect said drill bit and drive it in rotation are so devised as to allow said drill bit to pass into any one of said four oblique holes to as to extend at the angle of the corresponding slope.

10. A surgical instrument for use to make a cut shaped as a cone in the proximal femur of a patient, said cone having a tip located on the postero lateral side at the sub-trochanteric level, a base located at the trans-trochanteric level and a central axis aligned with the axis of the femoral neck, all in the aim of reorienting at a given degree the femoral head in the acetabulum in a rotational fashion depending on the need of the patient, so as to transfer an ill zone in said femoral head from a weight bearing zone to a non-weight bearing zone, said instrument comprising:

a) a cutting guide attachable to a hollowed cervical screw previously inserted into the femoral head along the central axis of the cone to be cut, said guide, once fastened, being free to rotate relative to said cervical screw around the axis of said cervical screw;

b) a drilling bit passing through said guide in an oblique hole having a slope which corresponds to half the angle of the cone to be cut, in order to penetrate the bone at the level of the lateral wall of the femur as close as possible to said cervical screw and thus cut the cone by lateral displacement of the bit in a circular motion which is progressively enlarged as the drill bit moves forward in the femur head, thus initiating cutting of the cone from its tip to its base; and

c) means to connect the drill bit on the guide to drive it in rotation about its own axis, said means being also devised to allow the bit to be moved forward while it is rotated about the axis of the cervical screw,

wherein said guide is supported by a holding arm which is attachable to the femur in such a manner as to allow said guide to rotate about the axis of said cervical screw.

11. An instrument as defined in claim 10, wherein said holding arm includes means to adjust the angle of attachment of said holding arm to said guide and the angle of attachment of said holding arm to the femur, and means to adjust the length of the said holding arm.

12. An instrument as defined in claim 11, wherein said holding arm has a curve shaped central section, said central section having means allowing it to rotate completely about itself.

13. An instrument as defined in claim 10, wherein said holding arm has a curve shaped central section, said central section having means allowing it to rotate completely about itself.

14. An instrument as defined in claim 10, wherein means to connect said drill bit and drive it in rotation includes a rectilinear sliding system comprising an adjustment screw with a large number of threads per unit of length, for advancing a said bit along its own axes.

15. An instrument as defined in claim 14, wherein means to connect said drill bit and drive it in rotation also includes a turbine.

16. An instrument as defined in claim 15, wherein said guide includes at least four of said oblique hole each with a different slope, said slopes ranging between 25°

and 35°

, and wherein said means to connect said drill bit and drive it in rotation are so devised as to allow said drill bit to pass into any one of said four oblique holes to as to extend at the angle of the corresponding slope.

17. An instrument as defined in claim 10, wherein said guide includes at least four of said oblique hole each with a different slope, said slopes ranging between 25°

and 35°

, and wherein said means to connect said drill bit and drive it in rotation are so devised as to allow said drill bit to pass into any one of said four oblique holes to as to extend at the angle of the corresponding slope.

18. A surgical instrument for use to make a cut shaped as a cone in the proximal femur of a patient, said cone having a tip located on the postero lateral side at the sub-trochanteric level, a base located at the trans-trochanteric level and a central axis aligned with the axis of the femoral neck, all in the aim of reorienting at a given degree the femoral head in the acetabulum in a rotational fashion depending on the need of the patient, so as to transfer an ill zone in said femoral head from a weight bearing zone to a non-weight bearing zone, said instrument comprising;

.

a) a cutting guide attachable to a hollowed cervical screw previously inserted into the femoral head along the central axis of the cone to be cut, said guide, once fastened, being free to rotate relative to said cervical screw around the axis of said cervical screw;

b) a drilling bit passing through said guide in an oblique hole having a slope which corresponds to half the angle of the cone to be cut, in order to penetrate the bone at the level of the lateral wall of the femur as close as possible to said cervical screw and thus cut the cone by lateral displacement of the bit in a circular motion which is progressively enlarged as the drill bit moves forward in the femur head, thus initiating cutting of the cone from its tip to its base; and

c) means to connect the drill bit on the guide to drive it in rotation about its own axis, said means being also devised to allow the bit to be moved forward while it is rotated about the axis of the cervical screw,

wherein said means to connect said drill bit and drive it in rotation includes a turbine.

19. An instrument as defined in claim 18, wherein said guide includes at least four of said oblique holes each with a different slope, said slopes ranging between 25°

and 35°

, and wherein said means to connect said drill bit and drive it in rotation are so devised as to allow said drill bit to pass into any one of said four oblique holes to as to extend at the angle of the corresponding slope.

20. A surgical instrument for use to make a cut shaped as a cone in the proximal femur of a patient, said cone having a tip located on the postero lateral side at the sub-trochanteric level, a base located at the trans-trochanteric level and a central axis aligned with the axis of the femoral neck, all in the aim of reorienting at a given degree the femoral head in the acetabulum in a rotational fashion depending on the need of the patient, so as to transfer an ill zone in said femoral head from a weight bearing zone to a non-weight bearing zone, said instrument comprising:

a) a cutting guide attachable to a hollowed cervical screw previously inserted into the femoral head along the central axis of the cone to be cut, said guide, once fastened, being free to rotate relative to said cervical screw around the axis of said cervical screw;

b) a drilling bit passing through said guide in an oblique hole having a slope which corresponds to half the angle of the cone to be cut, in order to penetrate the bone at the level of the lateral wall of the femur as close as possible to said cervical screw and thus cut the cone by lateral displacement of the bit in a circular motion which is progressively enlarged as the drill bit moves forward in the femur head, thus initiating cutting of the cone from its tip to its base; and

c) means to connect the drill bit on the guide to drive it in rotation about its own axis, said means being also devised to allow the bit to be moved forward while it is rotated about the axis of the cervical screw,

wherein said drill bit has a free end with a peripheral wall and appointed extremity that are very sharp and cutting, a base portion which allows said bit to be rigidly connected to said guide and to be driven in rotation, and a central portion with a surface that is smooth and non cutting.

21. An instrument, as defined in claim 20, wherein the middle portion of said drill bit is made of a flexible and resistant spring or cable.

22. An instrument, as defined in claim 21, wherein said middle portion of the drill bit is surrounded by a a slim and resistant protection guard.

23. An instrument, as defined in claim 22, wherein said protection guard includes one or more ball bearings.

24. An instrument, as defined in claim 20, wherein said middle portion of the drill bit is surrounded by a slim and resistant protection guard.

25. An instrument, as defined in claim 24, wherein said protection guard includes one or more ball bearings.

26. A surgical kit for use to make a cut shaped as a cone in the proximal femur of a patent, said cone having tip located on the postero lateral side at the sub-trochanteric level, a base located at the transtrochanteric level, and a central axis aligned with the axis of the femoral neck, all in the aim of reorienting rotationally at a given degree the femoral head in the acetabulum depending on the need of the patient, so as to allow displacement of a ill zone of the femoral head outside a weight bearing zone to a non weight bearing zone, said bit comprises, in combination:

a) a surgical instrument comprising

a cutting guide attachable to a hollowed cervical screw previously inserted into the femoral head along the central axis of the cone to be cut, said guide, once fastened, being free to rotate relative to said cervical screw around the axis of said cervical screw;

a drilling bit passing through said guide in an oblique hole having a slope which corresponds to half the angle of the cone to be cut, in order to penetrate the bone at the level of the lateral wall of the femur as close as possible to said cervical screw and thus cut the cone by lateral displacement of the bit in a circular motion which is progressively enlarged as the drill bit moves forward in the femur head, thus initiating cutting of the cone from its tip to its base; and

means to connect the drill bit on the guide to drive it in rotation about its own axis, said means being also devised to allow the bit to be moved forward while it is rotated about the axis of the cervical screw;

b) a chisel insertable into the cervical screw, said chisel having a distal extremity from which projects a plurality of cutting wings oriented at angle with respect to each other;

c) a compression plate insertable in said cervical screw after the cone has entirely been cut and after said surgical instrument has been removed, said plate having a proximal extremity provided with the same number of blades as the number of wings of the chisel, said blades being insertable in the slits left in the bone by said cutting wings of said chisel, said proximal extremity being provided with a central hole sized to fit into the distal extremity of said cervical screw, and means allowing it to be fastened to the patient'"'"'s femur;

d) a compression screw insertable in the said compression plate, and attachable to said centrally cervical screw; and

e) a stabilizing hook member attachable to the greater trochanter and reattachable by compression to said compression plate.

27. A surgical kit as defined in claim 26, wherein said compression plate has means to allow said stabilizing hook member to be fastened to said compression plate.

28. A surgical kit as defined in claim 27, wherein said stabilizing hook member includes an end part supporting two rigid hooks, two flexible metallic cables which project from said rigid hooks, a cable coupling plate, and two threaded screws which extend from said metallic cables.