WO2013025678A1

WO2013025678A1 - Electrode lead tissue anchor

Info

Publication number: WO2013025678A1
Application number: PCT/US2012/050702
Authority: WO
Inventors: Brian P. Watschke; Jelica DANILOVIC
Original assignee: Ams Research Corporation
Priority date: 2011-08-16
Filing date: 2012-08-14
Publication date: 2013-02-21

Abstract

An electrode lead (104) configured for implantation in tissue (128) of a patient comprises a lead body (110), an electrode (112) attached to a distal end (114) of the lead body, and a tissue anchor (126) attached to the distal end. The tissue anchor comprises a permanent anchor member (130) and a dissolvable anchor member (132). In one embodiment, the dissolvable anchor member comprises mesh.

Description

ELECTRODE LEAD TISSUE ANCHOR

BACKGROUND

[0001] Implantable electronic stimulator devices, such as neuromuscular stimulation devices, have been disclosed for use in the treatment of various pelvic conditions, such as urinary incontinence, fecal incontinence and sexual dysfunction. Such devices generally include one or more electrodes that are coupled to a control unit by electrode leads. A stimulation therapy is applied to the tissue through the electrode leads to treat the condition of the patient. Exemplary implantable electronic stimulator devices and uses of the devices are disclosed in U.S. Patent Nos. 6,354,991, 6,652,449, 6,712,772 and 6,862,480, each of which is hereby incorporated by reference in its entirety.

[0002] The electrode leads are typically secured to the tissue of the patient using a tissue anchor, such as a helical coil. The primary objective of the tissue anchor is to prevent migration of the electrode lead within the tissue of the patient, as such movement may adversely affect the stimulation therapy. However, it may be necessary to move the anchor within the tissue in order to test the efficacy of the various tissue locations for electrodes, or completely remove the anchor and the attached lead from the patient. Conventional anchors typically do not facilitate such anchor movement within the tissue of the patient.

SUMMARY

[0003] Embodiments are directed to an electrode lead that is configured for implantation in tissue of a patient. In one embodiment, the electrode lead comprises a lead body, an electrode attached to a distal end of the lead body, and a tissue anchor attached to the distal end. In one embodiment, the tissue anchor comprises a permanent anchor member and a dissolvable anchor member. In one embodiment, the dissolvable anchor member comprises mesh.

[0004] Additional embodiments are directed to a method. In one embodiment of the method, a distal end of a lead body is fed into tissue of a patient. In one embodiment, the distal end includes an electrode and a tissue anchor comprising a permanent anchor member and a dissolvable anchor member comprising mesh. Next, the distal end of the lead body is affixed to the tissue using the dissolvable anchor member. [0005] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not indented to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. The claimed subject matter is not limited to implementations that solve any or all disadvantages noted in the Background.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] FIG. 1 is a side plan view of an exemplary electronic stimulator device, in accordance with embodiments of the invention.

[0007] FIGS. 2-4 respectively show top, side and front views of an exemplary tissue anchor in accordance with embodiments of the invention.

[0008] FIGS. 5-7 respectively show top, side and front views of an exemplary tissue anchor in accordance with embodiments of the invention.

[0009] FIG. 8 is a top view of a distal end of an electrode lead illustrating a permanent anchor member in a compact state, in accordance with embodiments of the invention.

[0010] FIG. 9 is a front view of the distal end of the electrode lead provided in FIG. 8.

[0011] FIG. 10 is a front view of a distal end of an electrode lead illustrating a permanent anchor member in a compact state, in accordance with embodiments of the invention.

[0012] FIGS. 11 and 12 respectively show side and front views of a distal end of an electrode lead having a permanent anchor member in an expanded state, in accordance with embodiments of the invention.

[0013] FIG. 13 is a flowchart illustrating a method in accordance with embodiments of the invention.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

[0014] Embodiments of the invention are described more fully hereinafter with reference to the accompanying drawings. The various embodiments of the invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Elements that are identified using the same or similar reference characters refer to the same or similar elements.

[0015] It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements may be present. In contrast, if an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements present.

[0016] It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. Thus, a first element could be termed a second element without departing from the teachings of the present invention.

[0017] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0018] FIG. 1 is a side plan view of an exemplary electronic stimulator device 100 in accordance with embodiments of the invention. In one exemplary embodiment, the stimulator device 100 is configured for implantation into a pelvic region of a patient to provide muscle and/or nerve stimulation that is used to control and/or treat a pelvic condition of the patient, such as pelvic pain, urinary incontinence, fecal incontinence, erectile dysfunction or other pelvic condition that may be treated through electrical stimulation. Embodiments of the invention may also be used with other types of stimulator devices used to treat other patient conditions through electrical stimulation. [0019] In one embodiment, the device 100 comprises a control unit 102, and one or more electrode leads 104. In one embodiment, the leads 104 each include a proximal end 106 which is electrically coupled to the control unit 102 via a connector 108. Each electrode lead 104 comprises a lead body 110 and one or more stimulation elements or electrodes 112 attached to, or formed on, a distal end 114 of the lead body 110. In one embodiment, the electrodes 112 are separated from each other by an insulative portion or element 116. The lead body 110 insulates electrical wires 118 connecting the control unit 102 to the electrodes 112. The lead body 110 can be in the form of an insulating jacket typically comprising silicone, polyurethane, or other flexible, biocompatible, and electrically insulating material. Additional electrode leads 104 or physiological sensors may be coupled to the control unit 102.

[0020] In one embodiment, the control unit 102 comprises circuitry including at least one processor for processing electrical signals received from the one or more electrodes 112 or physiological sensors (not shown). In one embodiment, the control unit 102 includes a pulse generator circuit in accordance with one or more embodiments described herein, which is configured to generate current pulses that are delivered to tissue of a patient through the one or more electrodes 112.

[0021] In one embodiment, the control unit 102 is enclosed within a hermetically sealed metal housing 120 commonly referred to as a "can." The can 120 generally comprises first and second halves that are joined together in a laser- welding operation about their perimeters after the battery power supply and electronic circuitry are inserted in the space defined by the two halves of the can.

[0022] A header 122 includes a connector block 124 that may be molded in the header or inserted after the header has been molded. Feed-through conductors from the electronic circuitry within the can 120 are coupled to electrical contacts of the connector block 124. The connector block 124 includes one or more ports, each of which receives the connector 108 of each lead 104 and electrically couples the connector 108 to the electronic circuitry of the control unit 102 via the feed- through conductors.

[0023] In one embodiment, the distal end 114 of the electrode lead 104 can be anchored to tissue 128 of the patient (e.g., urinary sphincter muscle, anal sphincter muscle, etc.) by means of a tissue anchor 126, formed in accordance with embodiments of the invention. In one embodiment, the anchor 126 includes a permanent anchor member 130 and a dissolvable or absorbable anchor member 132.

[0024] In one embodiment, the dissolvable anchor member 132 is configured to be entirely absorbed by the patient after a period of time following its implantation within the tissue 128. The dissolvable anchor 132 may be formed of polyglycolide or polyglycolic acid (PGA), polylactide or polylactic acid (PCA), polydioxanone (PDO, PDS), or polycaprolactone (PCL), for example. In some embodiments, the dissolvable anchor member 132 is configured to dissolve in approximately 7-60 days following its implantation.

[0025] In one embodiment, the dissolvable anchor member 132 is configured to partially dissolve. That is, the dissolvable anchor member 132 may include both dissolvable and non- dissolvable portions.

[0026] In one embodiment, the dissolvable anchor 132 is in the form of a dissolvable mesh. Exemplary embodiments of the dissolvable mesh 132 include Dexon™ mesh produced by Covidien, or a biologic mesh/sling material, such as porcine mesh, or a polypropylene with absorbable fibers. While embodiments described herein refer to the dissolvable anchor 132 as dissolvable or absorbable mesh, it is understood that the dissolvable anchor member 132 may take on other forms without departing from the spirit and scope of the invention.

[0027] In one embodiment, the dissolvable anchor member 132 may be used to temporarily tack the distal end 114 of the lead 104 to the tissue of the patient in which it is implanted. When the dissolvable anchor member 132 is in the form of mesh, the mesh 132 can act like Velcro® to temporarily secure the electrode lead 104 in the desired position within the tissue of the patient while allowing the dissolvable anchor 132 to be moved within the tissue relatively easy compared to conventional tissue anchors, such as helical coils. This temporary anchoring of the electrode lead 104 is useful during the testing phase of the implantation where it may be necessary to test various locations of the electrodes 112.

[0028] After the testing phase of the implantation, the dissolvable anchor member 132 can securely anchor the distal end 114 of the lead 104 to the tissue until the dissolvable anchor member 132 is absorbed by the patient. For instance, when the dissolvable anchor member 132 comprises mesh, tissue ingrowth within the mesh 132 assists in firmly securing the distal end 114 of the lead 104 at the desired location within the tissue of the patient for a limited period of time. This anchoring function is terminated after the mesh 132 is absorbed by the patient.

[0029] Embodiments of the permanent anchor member 130 operate as a long term stability enhancer to prevent migration of the electrodes 112 from the desired targeted electrical stimulation site within the tissue of the patient following the absorption of the dissolvable anchor member 132. In one embodiment, the permanent anchor member 130 is formed of a suitable biocompatible material that can be maintained within a patient for an extended period of time. In one embodiment, the permanent anchor member 130 is formed of silicone, polypropylene, or other permanent biocompatible material.

[0030] In one embodiment, the permanent anchor member 130 attaches the distal end 114 of the electrode lead to the dissolvable anchor member 132. In one embodiment, the permanent anchor member 130 allows the electrode lead 104 to be extracted at a later date if the patient is not a candidate for long term electrical stimulation therapy, or if the electrode lead needs to be replaced. Such an extraction would be more difficult if the mesh 132 did not dissolve. For instance, tissue ingrowth through the mesh 132 would require a physician to dissect the tissue surrounding the mesh in order to remove the mesh and the attached electrode lead 104.

[0031] FIGS. 2-4 respectively show top, side and front views of an exemplary form of the anchor 126 in accordance with embodiments of the invention. In one embodiment, the permanent anchor member 130 comprises a base 134 and a lead attachment portion 136. In one embodiment, the lead attachment portion extends from the base 134 and is configured to couple to the lead body 110 of an electrode lead 104. In one embodiment, the lead attachment portion 136 is extended through the mesh 132, as shown in the simplified side view of FIG. 4. The attachment of the lead body 110 to the lead attachment portion 136 sandwiches the mesh 132 between the lead 104 and the base 134, as shown in FIGS. 2 and 4. This prevents the permanent anchor member 130 from detaching from the mesh 132.

[0032] In one embodiment, the lead attachment portion 136 is coupled to a portion of the lead body 110. In one embodiment, the lead attachment portion 136 is coupled to the distal end 114 of the electrode lead 104. In one embodiment, the electrode lead 104 attaches to the lead attachment portion 136 such that the electrodes 112 are located outside the lead attachment portion 136, as shown in FIGS. 2 and 3. [0033] In one embodiment, the lead attachment portion 136 comprises a bore 142. The distal end 114 of the electrode lead 104 is secured to the permanent anchor member 130 by feeding the distal end 114 through the bore 142. In one embodiment, sufficient frictional resistance between the interior surface of the bore 142 and the lead body 110 maintains the connection between the lead attachment portion 136 and the lead body 110 when subjected to forces that are likely to be encountered while implanted within a patient. In one embodiment, an adhesive is used to secure the lead body 110 within the bore 142. In accordance with another embodiment, the lead attachment portion 136 comprises a clip that may be opened to receive the lead body 110 and latched closed to secure the lead body 110 to the permanent anchor member 130.

[0034] FIGS. 5-7 respectively show top, side and front views of an exemplary form of the anchor 126 in accordance with embodiments of the invention. This embodiment of the anchor 126 is similar to that described above with reference to FIGS. 2-4, except for the manner in which the permanent anchor member 130 is attached to the dissolvable anchor member 132. In one embodiment, the base 134 includes one or more suture holes 148. In one embodiment, sutures 150 are passed through the suture holes 148 and through the mesh 132 to secure the permanent anchor member 130 to the mesh 132. This embodiment of the invention may be combined with that described above with reference to FIGS. 2-4 by positioning the mesh 132 between the lead attachment portion 136 and the base 134, and securing the mesh 132 to the permanent anchor member 130 using the sutures 150.

[0035] In accordance with another embodiment, the permanent anchor member 130 is attached to the mesh 132 using a suitable biocompatible adhesive. In accordance with one embodiment, the biocompatible adhesive is absorbable by the patient.

[0036] FIGS. 8-12 illustrate a tissue anchor 126 formed in accordance with other embodiments of the invention. In one embodiment, the permanent anchor member 130 is attached to the lead body 110 and comprises a compact state and an expanded state. FIG. 8 is a top view of the anchor 126 illustrating the permanent anchor member 130 in the compact state. FIG. 9 is a front view of the anchor 126 illustrated in FIG. 8. FIG. 10 is a front view of the anchor 126 with the permanent anchor member 130 in the compact state in accordance with another embodiment of the invention. FIGS. 11 and 12 respectively show the anchor 126 after the dissolvable anchor member 132 has been absorbed by the patient. [0037] In one embodiment, the permanent anchor member 130 comprises portions that are displaced a greater radial distance from the lead body 110 when in the expanded state than when the permanent anchor member 130 is in the compact state, as shown in FIGS. 9 and 11. In one embodiment, the permanent anchor member 130 comprises a plurality of deployable members 152. The deployable members 152 each have distal ends 154 that are held in close proximity to the lead body 110 when the permanent anchor member 130 is in the compact state, as shown in FIGS. 8-10. The distal ends 154 are displaced radially from the lead body 110 when the permanent anchor member 130 is in the expanded state, as shown in FIGS. 11 and 12.

[0038] In one embodiment, the permanent anchor member 130 is maintained in the compact state using a suitable biocompatible adhesive 156, which is absorbable by the patient, as shown in FIGS. 8 and 9. In one embodiment, the adhesive 156 also attaches the permanent anchor member 130 to the dissolvable anchor member or mesh 132, as shown in FIGS. 8 and 9. As the dissolvable adhesive 156 is absorbed by the patient along with the dissolvable anchor member 132, the lead body 110 is separated from the mesh 132 and the deployable members 152 are released from their compact state (FIGS. 8 and 9) and move to their expanded state (FIGS. 11 and 12). This movement from the compact state to the expanded state is driven by the formation of the permanent anchor member 132 in a manner that makes the expanded state the quiescent state of the permanent anchor member 130. As a result, a spring-like bias force is generated by the permanent anchor member 130 while it is maintained in the compact state. This bias force drives the deployable members 152 to the expanded state when the constraint imposed by the adhesive 156 and/or the mesh 132 is released.

[0039] In one embodiment, the mesh 132 is formed around the permanent anchor member 132 to constrain the deployable members 152 in the compact state, as shown in FIG. 10. In one embodiment, a suitable dissolvable biocompatible adhesive is also used to maintain the permanent anchor member 130 in the compact state. The anchor 126 transitions from the compact state to the expanded state when the dissolvable anchor member 132 and/or the adhesive is absorbed by the patient.

[0040] The expansion of the deployable members 152 into the tissue of the patient stabilizes the location of the permanent anchor member 130 within the tissue 128 (FIG. 1) of the patient and, therefore, the distal end 114 of the electrode lead 104 within the tissue 128 of the patient. Tissue ingrowth and encapsulation of the distal end 114 of the lead body 110 and the deployable members 152 enhances the fixation of the lead body 110 within the tissue.

[0041] FIG. 13 is a flowchart illustrating a method in accordance with embodiments of the invention. At 160 of the method, a distal end 114 of a lead body 110 is fed into tissue 128 (FIG. 1) of a patient. In one embodiment, the distal end 114 of the lead body 110 comprises an electrode 112 and a tissue anchor 126 formed in accordance with one or more of the embodiments described above. In one embodiment, the tissue anchor 126 comprises a permanent anchor member 130 and a dissolvable anchor member 132 comprising mesh.

[0042] At 162, the distal end 114 of the lead body 110 is affixed to the tissue 128 using the dissolvable anchor member 132. As discussed above, when the dissolvable anchor member 132 comprises dissolvable mesh, the mesh operates to tack the distal end 114 of the lead body 110 to the tissue. This allows for temporary placement of the distal end 114 during a testing phase of the implantation of the electrode lead 104. In one embodiment, the location of the one or more electrodes 112 are tested while the distal end 114 is tacked to the tissue of the patient using the dissolvable anchor member 132. In one embodiment, the testing includes delivering electrical stimulation pulses to the tissue 128 through the one or more electrodes 112 using, for example, a stimulator device (100) or a testing unit, in accordance with conventional techniques.

[0043] At 164, the dissolvable anchor member 132 is dissolved within the tissue 128. In one embodiment, this takes place after the completion of the testing phase and the permanent implantation of the electrode lead 104 in the tissue of the patient. The distal end 114 of the lead body 110 is then anchored to the tissue using the permanent anchor member 130.

[0044] In one embodiment of step 166, the permanent anchor member 130 comprises a compact state and an expanded state, as described above with reference to FIGS. 8-12. In one embodiment of the method, the permanent anchor member 130 is maintained in the compact state using the dissolvable anchor member 132 during steps 160 and 162 of the method. In one embodiment, the permanent anchor member 130 is transitioned from the compact state to the expanded state responsive to the dissolving step 164.

[0045] In one embodiment, the permanent anchor member 130 comprises a plurality of deployable members 152 that are maintained adjacent the lead body 110 using the dissolvable anchor member 132 or an adhesive. As the permanent anchor member 130 is transitioned from the compact state to the expanded state, distal ends 154 of the deployable members 152 move radially relative to the lead body 110 responsive to dissolving the dissolvable anchor member 132 (step 164) or through the dissolving of the biocompatible adhesive.

[0046] In one embodiment, the lead body 110 is attached to the permanent anchor member 130 prior to the feeding step 160. In one embodiment, the lead body 110 is extended through a bore 142 of the permanent anchor member 130 to facilitate the attachment of the lead body 110 to the permanent anchor member 130.

[0047] In one embodiment, the permanent anchor member 130 is attached to the dissolvable anchor member 132 prior to the feeding step 160. In one embodiment, the permanent anchor member 130 is extended through the dissolvable anchor member 132 to facilitate the attachment of the permanent anchor member 130 to the dissolvable anchor member 132.

[0048] In one embodiment, the electrode lead 104 and anchor 126 formed in accordance with embodiments of the invention are provided in a kit. In one embodiment, the kit comes assembled with the permanent anchor member 130 attached to the mesh 132 and the lead body 110 attached to the permanent anchor member 130.

[0049] Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.

Claims

WHAT IS CLAIMED IS:

1. An electrode lead (104) comprising:

a lead body (110);

an electrode (112) attached to a distal end (114) of the lead body; and

a tissue anchor (126) attached to the distal end of the lead body comprising:

a permanent anchor member (130); and

a dissolvable anchor member (132).

2. The electrode lead of claim 1, wherein the dissolvable anchor member comprises dissolvable mesh.

3. The electrode lead of claim 1, wherein the permanent anchor member comprises a lead attachment portion (136) attached to the lead body.

4. The electrode lead of claim 3, wherein the lead body extends through a bore (142) of the lead attachment portion.

5. The electrode lead of claim 1, wherein the dissolvable anchor member is attached to the permanent anchor member.

6. The electrode lead of claim 5, wherein the permanent anchor member extends through the dissolvable anchor member.

7. The electrode lead of claim 6, wherein the permanent anchor member comprises first and second portions (134, 136) respectively located on first and second sides of the dissolvable anchor member.

8. The electrode lead of claim 1, wherein:

the permanent anchor member comprises a plurality of suture holes (148); and

the electrode lead comprises sutures (150) that pass through the suture holes and attach the permanent anchor member to the dissolvable anchor member.

9. The electrode lead of claim 1, further comprising a biocompatible adhesive (156) that bonds the permanent anchor member to the dissolvable anchor member.

10. The electrode lead of claim 1, wherein:

the permanent anchor member comprises a compact state and expanded state, wherein portions of the permanent anchor member are displaced a greater radial distance from the lead body when the permanent anchor member is in the expanded state than when the permanent anchor member is in the compact state; the permanent anchor member is biased toward the expanded state; and

the dissolvable anchor member maintains the permanent anchor member in the compact state.

11. The electrode lead of claim 10, wherein the permanent anchor member comprises a plurality of deployable members (152) each having distal ends (154) that are held by the dissolvable anchor member adjacent the lead body when the permanent anchor member is in the compact state, the distal ends of the deployable members move radially from the lead body when released by the dissolvable anchor member to place the permanent anchor member in the expanded state.

12. A method comprising:

feeding (160) a distal end (114) of a lead body (110) into tissue (128) of a patient, the distal end including an electrode (112) and a tissue anchor (126) comprising a permanent anchor member (130) and a dissolvable anchor member (132); and affixing (162) the distal end of the lead body to the tissue using the dissolvable anchor member.

13. The method of claim 12, further comprising testing the location of the electrode including delivering electrical stimulation pulses to the tissue through the electrode.

14. The method of claim 12, further comprising dissolving (164) the dissolvable anchor member within the tissue of the patient.

15. The method of claim 12, wherein:

the permanent anchor member comprises a compact state and an expanded state, wherein portions of the permanent anchor member are displaced a greater radial distance from the lead body when the permanent anchor member is in the expanded state than when the permanent anchor member is in the compact state; and the method further comprising maintaining the permanent anchor member in the compact state using the dissolvable anchor member.

16. The method of claim 15, further comprising:

dissolving (164) the dissolvable anchor member within the tissue of a patient; and transitioning the permanent anchor member from the compact state to the expanded state responsive to dissolving the dissolvable anchor member.

17. The method of claim 16, wherein:

the permanent anchor member comprises a plurality of deployable members (152) each having distal ends (154);

maintaining the permanent anchor member in the compact state using the dissolvable anchor member comprises holding the distal ends of the deployable members adjacent the lead body using the dissolvable anchor member; and

transitioning the permanent anchor member from the compact state to the expanded state comprises moving the distal ends of the deployable members radially relative to the lead body responsive to dissolving the dissolvable anchor member.

18. The method of claim 12, further comprising attaching the permanent anchor member to the lead body.

19. The method of claim 18, wherein attaching the permanent anchor member to the lead body comprises extending the lead body through a bore (142) of the permanent anchor member.

20. The method of claim 12, wherein:

the dissolvable anchor member comprises a dissolvable mesh; and

affixing the distal end of the lead body to the tissue using the dissolvable anchor member comprises affixing the distal end of the lead body to the tissue using the mesh.