Percutaneous leads with laterally displaceable portions, and associated systems and methods

1. A patient treatment device, comprising a lead body that includes:

a first percutaneous portion carrying a plurality of electrodes and having a first aperture extending into the first percutaneous portion, the first percutaneous portion having a first diameter and a first portion of a bayonet fitting, the stylet;

a second percutaneous portion spaced apart from the first percutaneous portion and having a second aperture extending entirely through the second percutaneous portion, the second percutaneous portion having a second diameter; and

a third percutaneous portion positioned between the first and second portions along a deployment axis and having a third diameter less than the first and second diameters, the third portion having a stiffness in a direction transverse to the deployment axis that is less than a stiffness of the first portion transverse to the deployment axis, and less than a stiffness of the second portion transverse to the deployment axis, the third portion including multiple electrical signal paths between the second portion and the electrodes of the first portion; and

a stylet removably received in the first and second apertures, the stylet having a second portion of the bayonet fitting and the first percutaneous portion being releasably coupled with the bayonet fitting, with the stylet being rotatable about the deployment axis and translatable along the deployment axis relative to the first percutaneous portion between a secured position and an unsecured position.

2. The device of claim 1 wherein the third diameter is less than one quarter of the first diameter, and less than one quarter of the second diameter.

3. The device of claim 1 wherein the first portion has a uniform first diameter, and wherein the electrodes are exposed around a circumference of the first portion.

4. The device of claim 1 wherein the multiple electrical signal paths are part of a flexible electrical link that is coupled to the electrodes and is unsupported between the first and second portions in a direction transverse to the deployment axis.

5. The device of claim 4 wherein the electrical link includes an insulated wire.

6. The device of claim 5 , further comprising an axial reinforcing fiber arranged along the wire.

7. The device of claim 4 wherein the electrical link includes a ribbon of insulated wires.

8. The device of claim 4 wherein the second portion includes a plurality of electrical terminals, and wherein the electrical link is connected between the plurality of electrodes and the plurality of electrical terminals.

9. The device of claim 1 wherein the third portion does not include an aperture.

10. The device of claim 1 wherein the electrical signal paths of the third portion include multiple flexible electrical links, with individual electrical links coupled to corresponding individual electrodes and with the individual electrical links unsupported between the first and second portions in a direction transverse to the deployment axis, the individual electrical links being movable relative to each other between the first and second portions.

11. The device of claim 1 wherein the first portion includes a fixation device positioned to fix the first portion relative to adjacent tissue.

12. The device of claim 11 wherein the fixation device includes a tine.

13. The device of claim 11 wherein the fixation device includes a proximally-facing cup positioned annularly around the first portion and extending radially outwardly from the first portion.

14. The device of claim 1 wherein the second portion includes a fixation device positioned to fix the second portion relative to adjacent tissue.

15. The device of claim 14 wherein the fixation device includes a suture.

16. A patient treatment device, comprising a lead body that includes:

a first percutaneous portion carrying multiple electrodes and having a first aperture extending into the first percutaneous portion and a first portion of a bayonet fitting, the stylet;

a second percutaneous portion spaced apart from the first percutaneous portion, carrying multiple terminals and having a second aperture extending entirely through the second percutaneous portion;

a third percutaneous portion positioned between the first and second portions along a deployment axis, the third portion having a stiffness in a direction transverse to the deployment axis that is less than a stiffness of the first portion transverse to the deployment axis, and less than a stiffness of the second portion transverse to the deployment axis, the third portion including multiple individual wires coupled between individual electrodes and corresponding terminals, the individual wires being movable relative to each other at the third portion, wherein the third portion does not include a shaft disposed around the individual wires; and

a stylet removably received in the first and second apertures, the stylet having a second portion of the bayonet fitting and the first percutaneous portion being releasably coupled with a bayonet fitting, with the stylet being rotatable about the deployment axis and translatable along the deployment axis relative to the first percutaneous portion between a secured position and an unsecured position.

17. The device of claim 16 wherein:

the first portion has a generally uniform first diameter;

the electrodes are generally cylindrical in shape and aligned along the deployment axis;

the second portion has a second generally uniform diameter equal to or approximately equal to the first diameter, and wherein the third portion has a third diameter less than both the first and second diameters.

18. The device of claim 16 wherein the first portion has a first convex rounded surface that intersects the deployment axis at the proximal end of the first portion, and wherein the second portion has a second convex rounded surface that intersects the deployment axis at the distal end of the second portion, the first and second convex rounded surfaces being positioned to be exposed to patient tissue after implantation.

19. A patient treatment device, comprising a lead body that includes:

a first percutaneous portion carrying multiple electrodes and having a first aperture extending into the first percutaneous portion, the first percutaneous portion having a first diameter a first portion of a bayonet fitting, the stylet and including a first tissue fixation element;

a second percutaneous portion spaced apart from the first percutaneous portion, carrying multiple terminals and having a second aperture extending entirely through the second percutaneous portion, the second percutaneous portion having a second diameter and including a second tissue fixation element; and

a third percutaneous portion positioned between the first and second portions along a deployment axis, the third portion having a third diameter less than the first diameter and less than the second diameter, the third portion having a stiffness in a direction transverse to the deployment axis that is less than a stiffness of the first portion transverse to the deployment axis, and less than a stiffness of the second portion transverse to the deployment axis, the third portion including multiple individual wires coupled between individual electrodes and corresponding terminals, the individual wires being movable relative to each other at the third portion, wherein the third portion does not include a shaft disposed around the individual wires; and

a delivery stylet extending through the second aperture and into the first aperture, with the individual wires arranged externally to the stylet between the first and second portions, the stylet having a second portion of the bayonet fitting and the first percutaneous portion being releasably coupled with the bayonet fitting, with the stylet being rotatable about the deployment axis and translatable along the deployment axis relative to the first percutaneous portion between a secured position and an unsecured position.