Flexible cutting tool and methods for its use

• US 6,068,642 A
• Filed: 08/31/1998
• Issued: 05/30/2000
• Est. Priority Date: 03/01/1996
• Status: Expired due to Term

• Current Assignee: Distalock, Llc
• Original Assignee: Orthopedic Innovations Inc. (Wi-LAN Inc.)
• Inventors: Sutton, Gregg S., Stursa, Bruce Wayne, Johnson, Wesley D., Peterson, Francis C.
• Primary Examiner(s): Buiz, Michael
• Assistant Examiner(s): TRINH, HOA B
• Application Number:
  US09/142,065
• Time in Patent Office: 638 Days
• Field of Search: 606/180, 606/167, 606/166, 606/170-171, 606/173, 128/898, 128/899, 604/22
• US Class Current: 606/180
• CPC Class Codes: A61B 17/1615 Drill bits, i.e. rotating tools extending from a handpiece to contact the worked material
• CPC Class Codes: A61B 17/1631 Special drive shafts, e.g. flexible shafts A61B17/1642, A61B17/164 take precedence
• CPC Class Codes: A61B 17/17 Guides or aligning means for drills , mills, pins or wires
• CPC Class Codes: A61B 17/1757 for the spine
• CPC Class Codes: A61B 17/32002 with continuously rotating, oscillating or reciprocating cutting instruments
• CPC Class Codes: A61B 2017/00261 Discectomy
• CPC Class Codes: A61B 2017/00867 shape memory effect
• CPC Class Codes: A61B 2017/320733 with a flexible cutting or scraping element, e.g. with a whip-like distal filament member

Abstract

A cable comprising helically wound superelastic fibers and having a drilling tip provided at its distal end is housed in an elongated holder through which the cable may be advanced, the holder having a distal end for supporting the cable during a drilling operation and through which the distal end of the cable may protrude. The holder includes contains a cable support shaped to bend the cable through a predetermined angle adjacent its distal end and to support the cable as it is rotated and advanced. A motor is attached to the cable remote from the distal end of the cable to rotate the cable in a direction tending to tighten the cable fibers.

Claims

1. A cutting tool comprising:

an elongated, flexible cutting element having a longitudinal axis about which the cutting element may be rotated and comprising at least one cable, each at least one cable comprising an outer layer of helically wound fibers, and cutting means comprising at least one fiber having a cutting edge disposed at the distal end of the cutting element to perform a cutting function when the cutting element is rotated;

a motor attached to said cutting element remote from its distal end for rotating the cutting element about its longitudinal axis; and

an elongated holder having an opening for supporting the cutting element and through which the cutting element may be advanced axially, the holder having a distal end and opening for supporting the cutting element during a drilling operation and through which the distal end of the cutting element protrudes and advances, the holder including a cutting element support shaped to orient the longitudinal axis of the cutting element adjacent its distal end and to maintain such orientation as the cutting element is rotated and advanced in a cutting operation.

2. The cutting tool of claim 1 wherein said at least one cable is made of superelastic alloy fibers.

3. The cutting tool of claim 1 wherein the cutting element comprises a single cable and wherein the fibers are helically wound in a clockwise or counterclockwise direction toward said distal end and wherein said motor rotates the cable in the other direction.

4. The cutting tool of claim 3 wherein the at least one fiber defines a loop adjacent the distal end of the cable, the loop tending to enlarge under centrifugal force and axial compression.

5. The cutting tool of claim 3 wherein the distal end of the cable is woven to define an open basket configuration.

6. The cutting tool of claim 1 wherein said at least one fiber is cut across its width at an angle perpendicular to the longitudinal axis of the cutting element.

7. The cutting tool of claim 3 wherein said cable is so formed as to enable fibers adjacent the distal end of the cable to separate from each other slightly, whereby, in a drilling operation, the diameter of the hole that is drilled is slightly larger than the diameter of the cable adjacent but spaced from its distal end.

8. The invention of claim 7 wherein the cable and motor are selected so that fibers at the distal end of the cable are enabled to separate from each other under centrifugal force as the motor rotates the cable.

9. The invention of claim 7 wherein the cable is so formed as to enable the fibers adjacent the distal end of the cable to bow outwardly as the cable is axially compressed against a floor of a bore.

10. The cutting tool of claim 1 wherein said elongated holder includes a supporting surface positioned to contact and support said at least one cable at one or more points along its length.

11. The cutting tool of claim 10 wherein said elongated holder has a hollow interior with interior walls thereof forming said supporting surface.

12. The cutting tool of claim 6 wherein said elongated holder comprises a tubular support housing and supporting said at least one cable throughout substantially its entire length.

13. The cutting tool of claim 1 including a separate drill bit secured to the distal end of the at least one cable.

14. The cutting tool of claim 1 wherein said flexible cutting element comprises a bundle of cables so formed as to enable individual cables adjacent the distal end of the cutting element to separate from each other slightly, whereby, in a drilling operation, the diameter of the hole that is drilled is slightly larger than the diameter of the cable bundle adjacent but spaced from its distal end.

15. The cutting tool of claim 14 wherein the flexible cutting element and motor are selected so that cables at the distal end of the cutting element are enabled to separate from each other under centrifugal force as the motor rotates the cutting element.

16. The cutting tool of claim 14 wherein the cutting element is so formed as to enable cables adjacent their distal ends to bow outwardly as the cable bundle is axially compressed against a floor of a bore.

17. The cutting tool of claim 1 including a drive tube gripping said cutting element and rotationally driven by said motor, said drive tube being telescopically moveable with respect to said elongated holder so that movement of the drive tube distally with respect to the elongated holder causes said cutting element to protrude from the cutting element support.

18. In a surgical procedure, a method for fastening an intramedullary rod to the bone within which the rod is received, the method comprising the steps of:

providing a drill including an elongated, flexible cutting element having a longitudinal axis about which the cutting element may be rotated and comprising a cable or bundle of parallel cables each cable comprising an outer layer of helically wound fibers, and cutting means disposed at the distal end of the cutting element to perform a cutting function when the cutting element is rotated;

a motor attached to said cutting element remote from its distal end for rotating the cutting element about its longitudinal axis, and an elongated holder receivable in the intramedullary rod, the holder having a distal end for supporting the cutting element during a drilling operation and having an opening through which the distal end of the cutting element protrudes, the holder including a cutting element support shaped to orient the cutting element through substantially a right angle adjacent its distal end and to maintain such orientation as the cutting element is rotated and advanced distally;

positioning the holder in the intramedullary rod and aligning the hole in the holder with a preformed hole in the rod;

advancing said cutting means distally through the aligned holes in the holder and rod and against and through said bone while rotating said cutting element and continuously maintaining the cutting means at least partially within the hole being drilled;

locating the point of exit of the drill from the bone; and

inserting a screw fastener inwardly through the bone and intramedullary rod.

19. The method of claim 18 including the step of advancing said cutting element through soft tissues overlying said bone and through the skin.

20. The method of claim 18 wherein said fibers are formed at the distal end of the cutting element so as to themselves form said cutting means, and wherein said cutting element is rotated so that fibers at the distal end of the cutting element separate from each other so as to drill a hole in said bone of a diameter larger than the diameter of the cutting element adjacent but spaced from its distal end.