Devices and methods for interlocking surgical screws and nails

• US 20060084997A1
• Filed: 10/05/2005
• Published: 04/20/2006
• Est. Priority Date: 10/05/2004
• Status: Active Grant

• Current Assignee: Michigan State University
• Original Assignee: Michigan State University
• Inventors: Dejardin, Loic M.
• Granted Patent: US 8,435,238 B2
• Time in Patent Office: Days
• US Class Current: 606/62
• CPC Class Codes: A61B 17/1725 for applying transverse screws or pins through intramedullary nails or pins
• CPC Class Codes: A61B 17/72 Intramedullary pins, nails or other devices A61B17/744 takes precedence
• CPC Class Codes: A61B 17/725 with locking pins or screws of special form
• CPC Class Codes: A61B 17/7283 with special cross-section of the nail
• CPC Class Codes: A61B 17/8625 Shanks, i.e. parts contacting bone tissue
• CPC Class Codes: A61B 17/8635 Tips of screws
• CPC Class Codes: A61B 17/921 for intramedullary devices
• CPC Class Codes: A61D 1/00 Surgical instruments for veterinary use
• CPC Class Codes: A61F 2002/307 Prostheses for animals
• CPC Class Codes: A61F 2250/0081 Prosthesis for animals

Abstract

The present invention demonstrates and improved interlocking nail and screw combination to repair fracture bones. The preferred combination uses an hourglass shaped intramedullary nail wherein the larger ends of the nail have holes capable of receiving screws. The holes may, or may not be conical. Further, the holes may or may not be threaded. The surgical screws have a variety of thread patterns, or lack threads. A non-threaded end is believed to improve healing because of a larger core diameter as compared to a comparably sized threaded screw end.

Claims

1. An intramedullary nail and screw combination, comprising:

a) an intramedullary nail, comprising a first end section, a central section and second end section, wherein each have a diameter and wherein at least one of the end sections has at least one substantially transverse conical hole therethrough, wherein the transverse conical hole has an inner surface, and wherein the diameter of the first and second end sections are larger than the diameter of the central section; and

b) one or more screws each comprising a cylindrical first end section, a conical central section, and a cylindrical second end section with threads;

wherein the conical central section of the screw has an outer surface configured to fit with the transverse conical hole inner surface.

2. The intramedullary nail and screw combination of claim 1, further comprising threads on the conical central section of the screw.

3. The intramedullary nail and screw combination of claim 2, wherein the nail is formed of a material which has a first hardness and the screw is formed of a material which has a second hardness, and the second hardness is greater than the first hardness.

4. The intramedullary nail and screw combination of claim 2, wherein the threads on the conical central section of the screw are deformable.

5. The intramedullary nail and screw combination of claim 1, further comprising threads in the transverse conical hole.

6. The intramedullary nail and screw combination of claim 5, wherein the threads in the transverse conical hole are deformable.

7. The intramedullary nail and screw combination of claim 1, further comprising threads on the conical central section of the screw and threads in the transverse conical hole.

8. The intramedullary nail and screw combination of claim 7, wherein the threads on the conical central section of the screw are sized so as to allow interlocking with the threads in the transverse conical hole.

9. The intramedullary nail and screw combination of claim 1, wherein, once joined, the screw conical central section outer surface and the transverse conical hole inner surface are resistant to separation when being acted upon by torsional or bending forces.

10. A method for providing support for a fractured bone, comprising:

a) providing;

i) a bone comprising a cortex and an inner volume within the cortex;

ii) an intramedullary nail, comprising a first end section, a central section and second end section, wherein each have a diameter, and wherein at least one of the end sections has at least one substantially transverse conical hole therethrough, wherein the transverse conical hole has an inner surface, and wherein the diameter of the first and second end sections are larger than the diameter of the central section; and

iii) one or more screws each comprising a cylindrical first end section, a conical central section, and a cylindrical second end section with threads;

wherein the conical central section of the screw has an outer surface configured to fit with the transverse conical hole inner surface;

b) placing at least a portion of the intramedullary nail into the inner volume of the bone; and

c) inserting the screw into the transverse conical hole such that the screw conical central section outer surface contacts the conical hole inner surface and the cylindrical first end section of the screw protrudes from the nail and contacts the bone cortex, the conical central section of the screw contacts the nail, and the cylindrical second end section of the screw protrudes from the nail and threads into the bone cortex.

11. The methods of claim 10, wherein inserting the screw into the transverse conical hole further comprises tightening the screw in the transverse conical hole.

12. The method of claim 10, wherein the screw conical central section further comprises threads and the transverse conical hole further comprises threads, and wherein inserting the screw into the transverse conical hole further comprises tightening the screw in the transverse conical hole so that the screw conical central section threads and the transverse conical hole threads interlock.

13. The method of claim 10, wherein the method is practiced during a surgical procedure on a human.

14. The method of claim 10, wherein the method is practiced during a surgical procedure on an animal which is not human.

15. A method for providing support for a fractured bone, comprising:

a) providing;

i) a subject with a fractured bone, said fractured bone comprising a cortex and an inner volume;

ii) an intramedullary nail, comprising a first end section, a central section and second end section, wherein each have a diameter and wherein at least one of the end sections has at least one substantially transverse conical hole therethrough, wherein the transverse conical hole has an inner surface, and wherein the diameter of the first and second end sections are larger than the diameters of the central section; and

iii) one or more screws each comprising a cylindrical first end section, a conical central section, and a cylindrical second end section with threads;

wherein the conical central section of the screw has an outer surface configured to fit with the transverse conical hole inner surface;

b) placing at least a portion of the intramedullary nail into the inner volume of the bone;

c) drilling one or more holes through the bone cortex in a location which is substantially in line with a transverse conical hole in the nail; and

d) inserting the screw into the hole in the bone cortex and transverse conical hole such that the screw conical central section outer surface contacts the conical hole inner surface, the cylindrical first end section of the screw protrudes from the nail and contacts the bone cortex, the conical central section of the screw contacts the nail, and the cylindrical second end section of the screw protrudes from the nail and threads into the bone cortex.

16. The method of claim 15, wherein the subject is human.

17. The method of claim 15, wherein the subject is not human.

18. The method of claim 15, further comprising removing the screw and nail from the bone after the fracture heals.