Splittable sheath
A splittable sheath for an implantable medical device can include a jacket having an outer diameter and an inner diameter. A lumen can be defined by the inner diameter and extended from a proximal end to a distal end of the jacket. An electrode can be located at the distal end of the jacket. A signal wire can be disposed within the jacket and can be electrically coupled to the electrode. A rail can be configured to shield the signal wire from a cut path of a sheath splitter. In some examples, the sheath can further include a second rail. For instance, the signal wire can be located between a first rail and a second rail along the length of the sheath. The cut path can be located between the first rail and the second rail on a radially opposing side of the sheath from the signal wire.
1 . A splittable sheath for an implantable medical device, the sheath comprising:
a jacket including an annular wall extending from a proximal end to a distal end and having an outer diameter and an inner diameter, wherein the annular wall includes a jacket section and a jacket stripe section extending from the proximal end to the distal end, and wherein the jacket stripe section is constructed from a material that is softer than a material of the jacket section;
a lumen defined by the inner diameter and extended from the proximal end to the distal end of the jacket;
an electrode located at the distal end of the jacket;
a signal wire disposed within the jacket and electrically coupled to the electrode; and
a plurality of guard rails configured to shield the signal wire from a cut path of a sheath splitter, the plurality of guard rails defining a cut zone extending in a longitudinal direction along the jacket, wherein when the splittable sheath is unsplit the cut zone has a radial cut zone angle that is larger at the proximal end than at the distal end of the jacket.
2 . The splittable sheath of claim 1 , wherein the plurality of guard rails include a first rail separated from a second rail by the radial cut zone angle.
3 . The splittable sheath of claim 2 , wherein the signal wire is located between the first rail and the second rail along the length of the sheath, and wherein the cut path is located between the first rail and the second rail on a radially opposing side of the sheath from the signal wire.
4 . The splittable sheath of claim 3 , wherein:
at the proximal end, the cut zone angle is greater than 270 degrees, and
at the distal end, the cut zone angle is less than 90 degrees.
5 . The splittable sheath of claim 3 , wherein the cut zone is defined between the first rail and the second rail on a radially opposing side of the sheath from the signal wire.
6 . The splittable sheath of claim 1 , wherein the plurality of guard rails are exposed from the jacket at the proximal end.
7 . The splittable sheath of claim 1 , wherein the plurality of guard rails are constructed from a cut resistant material.
8 . The splittable sheath of claim 1 , wherein the plurality of guard rails are constructed from stainless steel.
9 . The splittable sheath of claim 1 , wherein the plurality of guard rails are configured to reduce debris formation caused by contact with the sheath splitter.
10 . The splittable sheath of claim 1 , wherein the plurality of guard rails include a solid cross section.
11 . The splittable sheath of claim 1 , wherein the signal wire is located at a bend plane along the cross section of the sheath.
12 . The splittable sheath of claim 1 , wherein the jacket includes two jacket stripe sections extending from the proximal end to the distal end.
13 . The splittable sheath of claim 1 , wherein the radial location of the signal wire remains constant along the length of the sheath.
14 . The splittable sheath of claim 1 , further comprising a pull wire disposed within the jacket, wherein the plurality of guard rails are further configured to shield the pull wire from the cut path.
15 . The splittable sheath of claim 1 , further comprising a lead disposed within the lumen of the sheath.
16 . A splittable sheath for an implantable medical device, the sheath comprising:
a jacket including an annular wall extending from a proximal end to a distal end and having an outer diameter and an inner diameter, wherein the annular wall includes a jacket section and a jacket stripe section extending from the proximal end to the distal end, and wherein the jacket stripe section is constructed from a material that is softer than a material of the jacket section;
a lumen defined by the inner diameter and extended from a proximal end to a distal end of the jacket;
an electrode located at the distal end of the jacket;
a signal wire disposed within the jacket and electrically coupled to the electrode; and
a first rail and a second rail each configured to shield the signal wire from a cut path of a sheath splitter, wherein the signal wire is located between the first rail and the second rail along the length of the sheath, wherein the cut path is located between the first rail and the second rail on a radially opposing side of the sheath from the signal wire, the first rail and the second rail each including a longitudinal segment extending in longitudinal direction along the jacket and defining a cut zone between the first rail and the second rail, and wherein when the splittable sheath is unsplit the cut zone has a radial cut zone angle that is larger at the proximal end than at the distal end of the jacket.
17 . A method for making a splittable sheath, the method comprising:
placing a lead liner over a lumen mandrel;
placing a signal wire liner over a signal wire mandrel;
locating a first rail mandrel and a second rail mandrel along an outer diameter of the lead liner, wherein the signal wire liner is located between the first rail mandrel and the second rail mandrel along the length of the sheath;
applying a jacket over the signal wire liner and the first and second rail mandrels, wherein the jacket includes an annular wall extending from a proximal end to a distal end,
wherein the annular wall includes a jacket section and a jacket stripe section extending from the proximal end to the distal end, and wherein the jacket stripe section is constructed from a material that is softer than a material of the jacket section;
removing each of the lumen mandrel, the signal wire mandrel, and the first and second rail mandrels, after the jacket is applied;
inserting a signal wire into the signal wire liner lumen, a first rail into the first rail lumen, and a second rail into the second rail lumen, after the lumen mandrel, the signal wire mandrel, and the first and second rail mandrels are removed, the first rail and the second rail each including a longitudinal segment extending in a longitudinal direction along the jacket and defining a cut zone between the first rail and the second rail, and wherein when the splittable sheath is unsplit the cut zone has a radial cut zone angle that is larger at the proximal end than at the distal end of the jacket; and
electrically coupling the signal wire to an electrode located on a distal end of the jacket.
18 . The method of claim 17 , further comprising disposing a braid around the signal wire liner and the first and second rail mandrels before applying the jacket, and wherein the jacket is extruded over the braid.
19 . The method of claim 17 , wherein applying the jacket includes placing an extruded profile over the signal wire liner, the first and second rail mandrels, and the lead liner.
20 . The method of claim 19 , wherein the extruded profile is heated to fuse the profile around the signal wire liner, the first and second rail mandrels, and the lead liner.
21 . The method of claim 17 , wherein placing the signal wire lumen includes placing the signal wire lumen along a bend plane of the sheath.
22 . The method of claim 17 , wherein inserting the first rail and the second rail includes inserting a first rail and a second rail that are constructed of a solid material to reduce debris formation.
23 . The method of claim 17 , wherein the first rail lumen and the second rail lumen are unlined and the first rail and the second rail are uncoated.