Devices for introduction into a body via a substantially straight conduit to form a predefined curved configuration, and methods employing such devices
View Patent ↗A device for introduction into a body in a straight configuration and assuming within the body a predefined curved configuration, includes an elongated element formed from a number of segments interconnected so as to form effective hinges therebetween. When the elongated element is confined to a straight state, the effective hinges transfer compressive forces from each segment to the next so that the elongated element can be pushed to advance it through a conduit. When the elongated element is not confined to a straight state, the effective hinges allow deflection of each segment relative to adjacent segments until abutment surfaces of the segments come into abutment, thereby defining a fully flexed state of the elongated element with a predefined curved configuration. The device can be produced with a wide range of two-dimensional and three-dimensional curved forms, and has both medical and non-medical applications.
1. A drill attachment comprising:
a drill member comprising:
(a) a rotatable drive shaft for communication with a drive input, the rotatable drive shaft including a distal flexible portion;
(b) a drill tip associated with the distal flexible portion of the rotatable drive shaft so as to rotate with the rotatable drive shaft;
(c) a sheath for enveloping at least a portion of the distal flexible portion of the rotatable drive shaft, the sheath including a plurality of segments; and
(d) an outer conduit through which the sheath extends and is movable therethrough,
wherein at least part of said sheath is sized for insertion into a hole drilled by said drill tip, and wherein successive segments of the sheath are configured to assume a predefined deflected position relative to adjacent segments when projecting beyond the outer conduit, but are limited to a straightened configuration within the outer conduit, such that, when a portion of the sheath is advanced relative to the outer conduit so as to extend beyond the outer conduit, the drill tip advances together with said portion of the sheath so as to drill the hole along a curved pathway.
2. The drill attachment of claim 1 , wherein said outer conduit is too large for insertion into the hole drilled by said drill tip, such that said drill tip advances along a curved pathway from a point of entry into a body.
3. The drill attachment of claim 1 , wherein a part of said outer conduit is sized for insertion into the hole drilled by said drill tip, such that said drill tip advances together with said part of said outer conduit along a straight path into a body to a first depth prior to following the curved pathway.
4. The drill attachment of claim 3 , further comprising a flange associated with said outer conduit to limit penetration of said outer conduit to said first depth.
5. The drill attachment of claim 1 , additionally comprising a biasing element deployed to bias the outer conduit towards said drill tip.
6. The drill attachment of claim 1 , wherein the segments of the sheath are connected to each other by pivotal connections.
7. The drill attachment of claim 1 , wherein the outer conduit includes a rectangular shaped internal cross section.
8. The drill attachment of claim 1 , wherein said sheath is configured to define an arcuate curved pathway.
9. The drill attachment of claim 1 , wherein said sheath is configured to define a helical curved pathway.
10. A method comprising the steps of:
(a) providing the drill attachment of claim 1 ;
(b) driving said drive shaft so as to rotate; and
(c) advancing said drill tip with said sheath into a body so as to drill a channel, at least part of said channel having a curved path.
11. The method of claim 10 , wherein said channel is straight to a first depth and then follows said curved path.
12. The method of claim 10 , wherein said curved path is arcuate.
13. The method of claim 10 , wherein said curved path is helical.
14. The method of claim 10 , wherein the body comprises a bone.
15. The method of claim 14 , further comprising employing at least part of said drill member as an orthopedic implant.
16. The method of claim 14 , further comprising withdrawing said drill member from said channel and inserting at least part of an orthopedic implant into said channel.
17. The method of claim 10 , wherein said channel passes through two vertebral bodies.
18. The method of claim 10 , wherein the body comprises at least part of at least one vertebral body.
19. A drill attachment comprising:
a drill member comprising:
(a) a rotatable drive shaft for communication with a drive input, the rotatable drive shaft including a distal flexible portion;
(b) a drill tip associated with the distal flexible portion of the rotatable drive shaft so as to rotate with the rotatable drive shaft;
(c) a sheath for enveloping at least a portion of the distal flexible portion of the rotatable drive shaft, the sheath including a plurality of segments; and
(d) an outer conduit through which the sheath extends and is movable therethrough,
wherein successive segments of the sheath are configured to assume a predefined deflected position relative to adjacent segments when projecting beyond the outer conduit, but are limited to a straightened configuration within the outer conduit, such that, when a portion of the sheath is advanced relative to the outer conduit so as to extend beyond the outer conduit, the drill tip advances along a curved pathway, and wherein said sheath is sized for insertion into a hole drilled by said drill tip, such that said drill tip advances along a straight path into a body to a first depth prior to following the curved pathway.
20. The drill attachment of claim 19 , further comprising a flange associated with said outer conduit to limit penetration of said outer conduit to said first depth.