Surgical reference frame fixation device with cannulated post and method of use

• US 6,893,447 B2
• Filed: 09/24/2001
• Issued: 05/17/2005
• Est. Priority Date: 09/24/2000
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Nalluri, Prasad, Ferrell, Michael S., Dominguez, Leonel
• Primary Examiner(s): HO, UYEN T
• Application Number:
  US09/961,616
• Publication Number:
  US 20020038126A1
• Time in Patent Office: 1,331 Days
• Field of Search: 606/130, 606 54- 59, 606/86, 606 96- 98, 600414-417, 600/421, 600/424
• US Class Current: 606/130
• CPC Class Codes: A61B 17/0642 for bones, e.g. for osteosynthesis or connecting tendon to bone
• CPC Class Codes: A61B 2017/0641 having at least three legs as part of one single body
• CPC Class Codes: A61B 2017/0647 having one single leg, e.g. tacks
• CPC Class Codes: A61B 2017/0648 threaded, e.g. tacks with a screw thread
• CPC Class Codes: A61B 90/11 with guides for needles or instruments, e.g. arcuate slides or ball joints

Abstract

A surgical fixation device for mounting a stereotactic reference frame to a patient. The device includes a mounting bracket assembly, a cannulated post, a base, an anchor tube, a plurality of percutaneous pins, and a driving device. The mounting bracket assembly is connected to a top portion of the post, whereas the base is slidably coupled to a bottom portion of the post, and defines a plurality of legs. The anchor tube extends distally from the post. The percutaneous pins extend distally from the legs, respectively. Finally, the driving device is connected to the post and is adapted to selectively contact the base. Upon final assembly, the base is longitudinally moveable relative to the anchor tube. The base can be moved to a retracted position such that the anchor tube is readily securable to a bony structure of the patient'"'"'s anatomy. Once secured, the base can be moved distally such that the percutaneous pins engage the bony structure as well, thereby promoting overall stability of the device.

Claims

1. A surgical fixation device for use in mounting a stereotactic reference frame to a patient, the device comprising:

a mounting bracket assembly adapted to selectively maintain a stereotactic reference frame;

a cannulated post defining a top portion, a central portion, a bottom portion, and a central passage, the top portion being connected to the mounting bracket assembly;

a base slidably coupled to the bottom portion of the post, the base defining a plurality of legs;

an anchor tube connected to, and extending distally from, the bottom portion of the post;

a plurality of percutaneous pins respective ones of which extend distally from respective ones of the legs; and

a driving device connected to the post proximal the base, the driving device adapted to selectively contact the base;

wherein upon final assembly, the base is longitudinally moveable relative to the anchor tube.

2. The device of claim 1, wherein the anchor tube terminates in a distal end opposite the post and each of the percutaneous pins forms a distal point extending opposite the base, and further wherein the device is adapted such that the base is longitudinally movable between a retracted position in which the distal points are proximally retracted relative to the distal end and an extended position in which the distal points are less proximally displaced relative to the distal end.

3. The device of claim 2, wherein the device is adapted such that in the extended position, the distal points are substantially level with the distal end.

4. The device of claim 1, wherein the mounting bracket assembly includes a bracket and a nut, the nut being threadably connected to the top portion of the post to couple the bracket to the post.

5. The device of claim 4, wherein the mounting bracket assembly further includes a retention pin selectively connecting the bracket to a portion of the post so as to selectively prevent rotation of the bracket relative to the post.

6. The device of claim 1, wherein the central portion of the post includes a shoulder defining a lower stop surface for selectively contacting the driving device.

7. The device of claim 6, wherein the shoulder further defines an upper stop surface for selectively contacting a portion of the mounting bracket assembly.

8. The device of claim 6, wherein the central portion further includes a threaded surface distal the shoulder.

9. The device of claim 8, wherein the threaded surface is adapted to threadably engage the driving device.

10. The device of claim 1, wherein the bottom portion of the post defines an outer surface adapted for slidably receiving the base.

11. The device of claim 10, wherein the outer surface is hexagonal in transverse cross-section.

12. The device of claim 1, wherein the bottom portion of the post defines an interior threaded surface adapted to threadably engage the anchor tube.

13. The device of claim 1, wherein the base includes three legs.

14. The device of claim 13, wherein the three legs are equidistantly spaced.

15. The device of claim 1, wherein each of the legs includes a foot adapted to receive a respective one of the pins.

16. The device of claim 1, wherein the base further includes a central body from which the plurality of legs extend, the central body defining an internal bore having a transverse cross-sectional shape corresponding with a transverse cross-sectional shape of the bottom portion of the post.

17. The device of claim 16, wherein the transverse cross-sectional shape is non-circular.

18. The device of claim 16, wherein the central body defines an upper engagement surface adapted to selectively contact a portion of the driving device.

19. The device of claim 1, wherein three of the percutaneous pins are provided.

20. The device of claim 1, wherein the driving device is a wing nut.

21. The device of claim 1, wherein the driving device is rotatably secured to the post proximal the base.

22. The device of claim 21, wherein the driving device is threadably secured to the post and defines a distal abutment surface, and further wherein distal movement of the driving device relative to the post causes the distal abutment surface to apply a force onto the base.

23. The device of claim 1, wherein the anchor tube includes a proximal end adapted for connection to the bottom portion of the post.

24. The device of claim 23, wherein the anchor tube further includes an intermediate flange adapted to selectively contact the base.

25. The device of claim 23, wherein the anchor tube further includes a distal end and a central passage, the central passage of the anchor tube having a reduced diameter at the distal end thereof.

26. A method of maintaining a reference frame relative to a patient'"'"'s anatomy as part of a surgical stereotactic procedure, the method comprising:

providing a surgical fixation device including a mounting bracket assembly, a cannulated post connected to the mounting bracket assembly, a base slidably connected to the post, an anchor tube extending distally from the post, percutaneous pins extending distally from the base, and a driving device for selectively contacting the base;

articulating the surgical fixation device to a retracted position in which distal points formed by the percutaneous pins are proximally retracted relative to a distal end of the anchor tube;

forming an incision through skin of the patient to expose a bony structure;

inserting the distal end of the anchor tube through the incision;

securing the distal end of the anchor tube to the bony structure;

forcing the percutaneous pins into engagement with the bony structure via movement of the base; and

mounting a stereotactic reference frame to the mounting bracket assembly.

27. The method of claim 26, wherein the base includes three legs each maintaining a distally extending percutaneous pin, and further wherein forcing the percutaneous pins into engagement with the bony structure includes driving three of the percutaneous pins into the bony structure.

28. The method of claim 27, wherein the three percutaneous pins are equidistantly spaced relative to a circumference of the anchor tube.

29. The method of claim 26, wherein forcing the percutaneous pins into engagement with the bony structure includes manipulating the driving device to impart a distal movement onto the base.

30. The method of claim 29, wherein the driving device includes a wing nut threadably secured to the post proximal the base, and further wherein manipulating the driving device includes rotating the wing nut about the post such that the wing nut moves distally into contact with the base.

31. The method of claim 26, wherein the base is slidable relative to the anchor tube such that forcing the percutaneous pins into engagement with the bony structure includes sliding the base relative to the anchor tube.

32. The method of claim 26, further comprising:

piercing the skin with the percutaneous pins prior to securing the distal end of the anchor tube to the bony structure.

33. The method of claim 26, wherein securing the distal end of the anchor tube to the bony structure includes coupling the distal end to the bony structure with a bone screw.

34. The method of claim 33, wherein the anchor tube includes a central passage, and further wherein coupling the distal end to the bony structure with a bone screw includes locating a portion of the bone screw within the central passage of the anchor tube.

35. The method of claim 34, further comprising:

creating a pilot hole in the bony structure below the distal end of the anchor tube prior to inserting the bone screw.

36. The method of claim 35, wherein creating a pilot hole includes guiding a hand drill through aligned, central passages of the post and the anchor tube.

37. The method of claim 26, wherein forcing the percutaneous pins into engagement with the bony structure includes stabilizing the fixation device relative to the bony structure.

38. The method of claim 26, further comprising:

a. registering the patient'"'"'s anatomy with a stereotactic system after mounting the reference frame to the mounting bracket assembly;

b. removing the reference frame relative to the patient'"'"'s anatomy, wherein the anchor tube remains secured to the bony structure;

c. sterilizing the reference frame; and

d. re-mounting the reference frame to the mounting bracket assembly.

39. The method of claim 38, wherein removing the reference frame includes disassembling the reference frame from the mounting bracket assembly.

40. The method of claim 38, wherein the mounting bracket assembly includes a bracket adapted to receive the reference frame and a retention device for coupling the bracket to the post, and further wherein removing the reference frame includes manipulating the retention device to release the bracket from the post.

41. The method of claim 26, wherein the bony structure is a cranium.

42. The method of claim 26, wherein the bony structure is a vertebra.

43. The method of claim 26, wherein the bony structure is a pelvic bone.

44. A method of manufacturing a surgical fixation device adapted for maintaining a stereotactic reference frame, the method comprising:

providing a cannulated post defining a top portion, a central portion, a bottom portion and a central passage;

connecting a driving device to the central portion of the post;

slidably connecting a base to the bottom portion of the post, the base having a plurality of percutaneous pins extending distally therefrom;

securing an anchor tube to the bottom portion of the post such that the anchor tube extends distally therefrom; and

mounting a mounting bracket assembly to the top portion of the post, the mounting bracket assembly adapted to receive a stereotactic reference frame;

wherein upon final assembly, the driving device is positioned to selectively contact the base such that the driving device selectively dictates distal sliding movement of the base relative to the anchor tube.

45. The method of claim 44, wherein upon final assembly, the base is slidable between a retracted position in which distal points formed by the percutaneous pins are proximally retracted relative to a distal end of the anchor tube and an extended position in which the distal point are less proximally retracted relative to the distal end of the anchor tube.

46. The method of claim 44, wherein the driving device includes a wing nut, and further wherein connecting the driving device to the post includes threading the wing nut to threads formed on the central portion of the post.

47. The method of claim 46, wherein the central portion further includes a shoulder proximal the threads, the shoulder defining an outer dimension greater than an inner diameter of the wing nut, and further wherein connecting the driving device to the post further includes:

a. co-axially sliding the wing nut over the bottom portion of the post;

b. threadably connecting the wing nut to the threads; and

c. rotating the wing nut along the threads such that the wing nut is proximate the shoulder prior to slidably connecting the base to the post.

48. The method of claim 44, wherein the bottom portion of the post and a central body of the base define corresponding receiving surfaces that are non-circular in transverse cross-section, and further wherein slidably connecting the base to the post includes aligning the receiving surface of the base with the receiving surface of the post.

49. The method of claim 44, wherein the base forms a plurality of legs, the method further comprising:

securing respective ones of the percutaneous pins to respective ones of the legs.

50. The method of claim 49, wherein each of the percutaneous pins are threadably secured to the respective legs.

51. The method of claim 49, wherein upon final assembly, the anchor tube is centrally positioned relative to the legs.

52. The method of claim 44, wherein the anchor tube is threadably secured to the post.

53. The method of claim 44, wherein the anchor tube forms a passage, and further wherein upon final assembly, the passage of the anchor tube is aligned with the central passage of the post.

54. The method of claim 44, wherein the mounting bracket assembly includes a bracket forming a bore and a nut, and further wherein mounting the mounting bracket assembly includes:

placing the bore over the top portion of the post; and

threadably securing the nut to the top portion such that the nut retains the bracket relative to the post.

55. The method of claim 44, wherein the mounting bracket assembly includes a bracket and a retention pin, and further wherein mounting the mounting bracket assembly includes:

connecting the retention pin to the bracket and the post such that the retention pin prevents rotation of the bracket relative to the post.