Devices, systems, and methods using a steerable stylet and flexible needle

1 . A stylet comprising:

a flexible body;

a steerable portion fixedly coupled to the flexible body, the steerable portion including a bend-resistive tip and a bendable section, the bendable section including a plurality of articulable segments and a plurality of joint pivots disposed between the plurality of articulable segments, wherein each joint pivot of the plurality of joint pivots intersects a central longitudinal axis of the steerable portion, wherein each articulable segment of the plurality of articulable segments is linked by a corresponding actuation cable of a plurality of actuation cables, wherein the bend-resistive tip includes a distal end and a proximal end, and wherein the plurality of actuation cables extend through the flexible body of the stylet and terminate distal to the proximal end of the bend-resistive tip of the steerable portion of the stylet; and

a sensor element extending through the flexible body,

wherein the stylet is movable within a lumen of an elongate instrument between a retracted condition in which the steerable portion is retracted within the elongate instrument and an extended configuration in which the steerable portion at least partially extends from the elongate instrument.

2 . The stylet of claim 1 , wherein the sensor element is configured to measure at least one of a shape or a position of at least a portion of the stylet.

3 . The stylet of claim 1 , further comprising a sensor conduit configured to maintain an axial position of the sensor element in substantially parallel alignment with a longitudinal axis of the elongate instrument.

4 . The stylet of claim 1 , further comprising:

a plurality of actuation conduits within the flexible body; and

a plurality of actuation channels within the steerable portion of the stylet,

wherein each actuation cable of the plurality of actuation cables extends through a discrete actuation conduit of the plurality of actuation conduits and anchors within a discrete actuation channel of the plurality of actuation channels.

5 . The stylet of claim 4 , wherein each actuation conduit of the plurality of actuation conduits is positioned immediately adjacent a neighboring actuation conduit of the plurality of actuation conduits.

6 . The stylet of claim 5 , further comprising a sensor conduit configured to maintain an axial position of the sensor element in substantially parallel alignment with a longitudinal axis of the elongate instrument, wherein the plurality of actuation conduits are arranged circumferentially around the sensor conduit.

7 . The stylet of claim 1 , wherein each actuation cable of the plurality of actuation cables maintains its radial position relative to a longitudinal axis of the stylet as each actuation cable extends from the flexible body into the steerable portion.

8 . The stylet of claim 1 , wherein:

a first joint pivot of the plurality of joint pivots is disposed between a first articulable segment of the plurality of articulable segments and a second articulable segment of the plurality of articulable segments, the first articulable segment being adjacent to the second articulable segment; and

a second joint pivot of the plurality of joint pivots is disposed between the second articulable segment and a third articulable segment of the plurality of articulable segments, the second articulable segment being adjacent to the third articulable segment.

9 . The stylet of claim 8 , wherein the first joint pivot allows the first articulable segment to bend in a first plane relative to the second articulable segment, and wherein the second joint pivot allows the second articulable segment to bend in a second plane relative to the third articulable segment, the first plane being different than the second plane.

10 . The stylet of claim 9 , wherein the first articulable segment is configured to bend in the first plane in response to actuation of a first actuation cable of the plurality of actuation cables, and wherein the second articulable segment is configured to bend in the second plane in response to actuation of a second actuation cable of the plurality of actuation cables, the actuation of the second actuation cable occurring while the first actuation cable is actuated.

11 . The stylet of claim 1 , wherein a first set of actuation cables of the plurality of actuation cables is positioned adjacent a first side of a first joint pivot of the plurality of joint pivots and a second set of actuation cables of the plurality of actuation cables is positioned adjacent a second side of the first joint pivot of the plurality of joint pivots.

12 . The stylet of claim 1 , wherein the sensor element extends coaxially along a central longitudinal axis of the stylet.

13 . A minimally invasive system comprising:

a stylet comprising:

a flexible body; and

a steerable portion including a bend-resistive tip, a bendable section, and a sensor element extending through the flexible body, wherein the bend-resistive tip includes a distal end and a proximal end,

wherein the stylet is movable within a lumen of a needle between a retracted condition in which the steerable portion is retracted within the lumen of the needle and an extended configuration in which the steerable portion of the stylet at least partially extends from a distal end of the needle; and

a plurality of actuation cables extending through the flexible body of the stylet and terminating distal to the proximal end of the bend-resistive tip of the steerable portion of the stylet, wherein the bendable section includes a plurality of articulable segments and a plurality of joint pivots disposed between the plurality of articulable segments, wherein each joint pivot of the plurality of joint pivots intersects a central longitudinal axis of the steerable portion, wherein each articulable segment of the plurality of articulable segments is linked by a corresponding actuation cable of the plurality of actuation cables.

14 . The minimally invasive system of claim 13 , wherein the sensor element is configured to measure a shape or a position of at least a portion of the stylet.

15 . The minimally invasive system of claim 13 , wherein the stylet includes an outer diameter that closely approximates an inner diameter of the lumen of the needle such that the sensor element is substantially aligned with a longitudinal axis of the needle when the stylet is received within the lumen of the needle.

16 . The minimally invasive system of claim 13 , further including:

a plurality of actuation conduits extending through the flexible body; and

a plurality of actuation channels extending through the steerable portion,

wherein each of the plurality of actuation cables extends through one of the plurality of actuation conduits and returns through another of the plurality of actuation conduits.

17 . The minimally invasive system of claim 13 , further including:

a plurality of actuation conduits extending through the flexible body; and

a plurality of actuation channels extending through the steerable portion,

wherein each of the plurality of actuation cables extends through one of the plurality of actuation conduits and anchors within one of the plurality of actuation channels.

18 . The minimally invasive system of claim 13 , wherein:

a first joint pivot of the plurality of joint pivots allows a first articulable segment of the plurality of articulable segments to bend in a first plane relative to a second articulable segment of the plurality of articulable segments; and

a second joint pivot of the plurality of joint pivots allows the second articulable segment to bend in a second plane relative to a third articulable segment of the plurality of articulable segments, wherein the first plane is different than the second plane.

19 . The minimally invasive system of claim 18 , wherein the first joint pivot is disposed between the first articulable segment and the second articulable segment, and wherein the second joint pivot is disposed between the second articulable segment and the third articulable segment.

20 . The minimally invasive system of claim 19 , wherein the first articulable segment is configured to bend in the first plane in response to actuation of a first actuation cable of the plurality of actuation cables, and wherein the second articulable segment is configured to bend in the second plane in response to actuation of a second actuation cable of the plurality of actuation cables, the actuation of the second actuation cable occurring while the first actuation cable is actuated.