Title:
MEDICAL ELECTRICAL LEAD
Kind Code:
A1


Abstract:
A medical device lead is presented. The lead includes one or more jacketed conductive elements. The jacket comprises one or more covers. At least one conductive element includes a profiled longitudinal cover of polyether ketone (PEEK), the profiled longitudinal cover includes at least one protruding end.



Inventors:
Boser, Gregory A. (Richfield, MN, US)
Seifert, Kevin R. (Forest Lake, MN, US)
Garlough, Greg (Bloomington, MN, US)
Application Number:
12/211092
Publication Date:
03/19/2009
Filing Date:
09/15/2008
Assignee:
Medtronic, Inc. (Minneapolis, MN, US)
Primary Class:
Other Classes:
29/874
International Classes:
H01B7/00; H01R43/16
View Patent Images:



Primary Examiner:
ANTHONY, JESSICA LYNN
Attorney, Agent or Firm:
Medtronic, Inc. (Minneapolis, MN, US)
Claims:
1. A medical electrical lead comprising: a lead body that comprises one or more insulated conductive elements; wherein at least one conductive element includes a profiled longitudinal element of polyether ketone (PEEK), the profiled longitudinal element includes at least one protruding end.

2. The medical electrical lead of claim 1 wherein the profiled longitudinal element includes a plurality of protruding ends.

3. The medical electrical lead of claim 1 wherein the at least one protruding end exhibits a flare about less than 90 degrees.

4. The medical electrical lead of claim 1 wherein the at least one protruding end exhibits a flare about less than 60 degrees.

5. The medical electrical lead of claim 1 wherein the at least one protruding end exhibits a flare about less than 45 degrees.

6. The medical electrical lead of claim 2 wherein the plurality of protruding ends includes a first flared protruding end and a second flared protruding end.

7. The medical electrical lead of claim 2 wherein the first protruding end and a second protruding end form a first channel to receive a first conductive element.

8. The medical electrical lead of claim 1 further comprising: a second cover of polymeric material coupled to the first longitudinal element, the second longitudinal element comprises one of PEEK/ethylene-tetrafluoroethylene (ETFE), polyvinylidene fluoride (PVDF)/ethylene-tetrafluoroethylene (ETFE), ETFE, silicone, fluorinated ethylene propylene (FEP), perfluoroalkoxy (PFA), and perfluorinated ethylene propylene (EFEP).

9. The medical electrical lead of claim 1 further comprising: a third longitudinal element of polymeric material coupled to the first longitudinal element, the third longitudinal element comprises one of PEEK/ETFE, PVDF/ETFE, ETFE, silicone, FEP, PFA, and EFEP.

10. A method of forming a medical electrical lead comprising: extruding PEEK over a mandrel to form at least one profiled longitudinal element, the longitudinal element includes a first protruding end and a second protruding end; cooling the at least one longitudinal element; and placing at least one conductive element between the first and the second protruding ends.

11. The method of claim 9, further comprising forming a second longitudinal element comprising one of PEEK, and ETFE.

12. The method of claim 10 wherein the profiled longitudinal element includes a plurality of flared protruding ends.

13. The method of claim 10 wherein the at least one flared protruding end exhibits a flare about less than 90 degrees.

14. The method of claim 10 wherein the at least one flared protruding end exhibits a flare about less than 60 degrees.

15. The method of claim 10 wherein the at least one flared protruding end exhibits a flare about less than 45 degrees.

16. A medical electrical lead comprising: a lead body that comprises one or more insulated conductive elements, wherein at least one conductive element includes a profiled longitudinal element of PEEK, the profiled longitudinal element possessing a substantially elliptical cross-section.

17. The medical electrical lead of claim 16 wherein the profiled longitudinal element comprises one or more channels formed by a set of protruding ends.

18. The medical electrical lead of claim 16 wherein the profiled longitudinal element comprises one or more channels formed by a set of protruding ends.

19. A medical electrical lead comprising: a lead body that comprises one or more insulated conductive elements, wherein at least one conductive element includes a profiled longitudinal element of PEEK, the profiled longitudinal element possessing a first, second, and third channel for receiving a first, second and third conductive elements.

20. The medical electrical lead of claim 19 further comprising a second longitudinal element, the second longitudinal element comprising one of PEEK/ETFE, PVDF/ETFE, ETFE, silicone, FEP, PFA, and EFEP.

Description:

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority and other benefits from U.S. Provisional Patent Application Ser. No. 60/973,479 filed Sep. 19, 2007, incorporated herein by reference in its entirety.

The present application also claims priority and other benefits from U.S. Provisional Patent Application Ser. No. 60/972,114 filed Sep. 13, 2007, incorporated herein by reference in its entirety.

TECHNICAL FIELD

The disclosure relates to implantable medical devices and, more particularly, to implantable medical leads.

BACKGROUND

The human anatomy includes many types of tissues that can either voluntarily or involuntarily, perform certain functions. After disease, injury, or natural defects, certain tissues may no longer operate within general anatomical norms. For example, after disease, injury, time, or combinations thereof, the heart muscle may begin to experience certain failures or deficiencies. Certain failures or deficiencies can be corrected or treated with implantable medical devices (IMDs), such as implantable pacemakers, implantable cardioverter defibrillator (ICD) devices, cardiac resynchronization therapy defibrillator devices, or combinations thereof.

IMDs detect and deliver therapy for a variety of medical conditions in patients. IMDs include implantable pulse generators (IPGs) or implantable cardioverter-defibrillators (ICDS) that deliver electrical stimuli to tissue of a patient. ICDs typically comprise, inter alia, a control module, a capacitor, and a battery that are housed in a hermetically sealed container with a lead extending therefrom. It is generally known that the hermetically sealed container can be implanted in a selected portion of the anatomical structure, such as in a chest or abdominal wall, and the lead can be inserted through various venous portions so that the tip portion can be positioned at the selected position near or in the muscle group. When therapy is required by a patient, the control module signals the battery to charge the capacitor, which in turn discharges electrical stimuli to tissue of a patient through via electrodes disposed on the lead, e.g., typically near the distal end of the lead. Typically, a medical electrical lead includes a flexible elongated body with one or more insulated elongated conductors. Each conductor electrically couples a sensing and/or a stimulation electrode of the lead to the control module through a connector module. It is desirable to develop implantable medical electrical leads with new lead body subassemblies.

BRIEF DESCRIPTION OF DRAWINGS

Aspects and features of the present invention will be appreciated as the same becomes better understood by reference to the following detailed description of the embodiments of the invention when considered in connection with the accompanying drawings, wherein:

FIG. 1 is a conceptual schematic view of an implantable medical device in which a medical electrical lead extends therefrom;

FIG. 2 is a schematic view of a medical electrical lead;

FIG. 3A is a schematic view of a distal end of the medical electrical lead;

FIG. 3B is a cross-sectional view taken along plane A-A of the distal end of the medical electrical lead depicted in FIG. 3A;

FIG. 4A is a schematic view of a jacket that surrounds one or more conductive elements in a medical electrical lead;

FIG. 4B is a schematic sectional view of the jacket depicted in FIG. 4A;

FIG. 5A is a schematic view of an exemplary insulated conductive element;

FIG. 5B is a cross-sectional view of the insulated conductive element depicted in FIG. 5A;

FIG. 6A is a schematic view of an exemplary insulated multi-conductor element;

FIG. 6B is a schematic cross-sectional view of an exemplary insulated multi-conductor element depicted in FIG. 6A;

FIG. 7A is a schematic view of another exemplary insulated multi-conductor element;

FIG. 7B is a schematic cross-sectional view of an exemplary insulated multi-conductor element depicted in FIG. 7A;

FIG. 8A is a schematic view of an exemplary insulated multi-conductor element before its stretched;

FIG. 8B is a schematic view of an exemplary insulated multi-conductor element being stretched;

FIG. 8C is an exemplary insulated multi-conductor element in a relaxed position and returning to its original coiled shape;

FIG. 9 is a schematic view of an exemplary insulated multi-conductor element wrapped around a tubular insulative element or a coil liner;

FIG. 10A is a schematic view of yet another exemplary insulated multi-conductor element wrapped around a mandrel;

FIG. 10B is a cross-sectional view of the insulated conductive element depicted in FIG. 10A;

FIG. 11 is a flow diagram for forming a coiled jacketed conductive element;

FIG. 12A depicts a schematic oblique view of a portion of a lead body that includes at least one profile-shaped longitudinal element with channels for placement of one or more elongate conductive elements;

FIG. 12B is a cross-sectional view of the portion of a lead body depicted in FIG. 12A

FIG. 13A depicts a schematic oblique view of a portion of a lead body that includes at least one profile-shaped longitudinal element with channels for placement of one or more elongate conductive elements;

FIG. 13B is a side view of a longitudinal protruding end, depicted in FIG. 13A, used to form longitudinal channels for placement of one or more elongate conductive elements; and

FIG. 13C is a side view of another longitudinal protruding end, depicted in FIG. 13A, used to form longitudinal channels for placement of one or more elongate conductive elements.

DETAILED DESCRIPTION

The present disclosure relates to a medical electrical lead that includes a lead body. The lead body comprises at least one elongated conductive element, such as a cable, surrounded by an elongated jacket. The jacket can include one or more covers. The jacket can be formed through an extrusion process directly over the conductive element, which reduces or eliminates diametrical expansion of the coiled conductive element which can occur due to elastic “springback” or stress relaxation of the coiled composite structure. A first cover comprises ethylene-tetrafluoroethylene (ETFE) extruded directly over the conductive element. In one embodiment, the conductive element and the jacket, is then formed into a coil.

In one embodiment, the PEEK undergoes a molecular mobility process prior to or during introduction of the ETFE over an elongated conductive element. Exemplary molecular mobility processes can include thermal annealing, stress relieving, or other suitable means for a material to achieve a more flexible molecular structure.

Thermal processing can involve exposing the composite structure to a controlled heating and cooling schedule. Suitable temperatures can depend upon the type of polymeric material and/or number of covers or layer(s) employed, to form a jacket, a composite jacket, or one or more longitudinal elements that can house conductive elements. ETFE, for example, can be thermally processed at about 130-200 degrees Celsius (° C.). Thermal processing of ETFE onto an elongated conductive element causes the conductive element to substantially maintain a controlled pitch and diameter after coiling. For example, a conductive element such as a cable in a coil shape can substantially maintain up to about 99 percent of its original coil shape, after the conductive element has been released from, for example, a mandrel which is after a thermal processing has been performed. The final diameter and pitch of a coil shape is generally based upon the coil composite structure and its elastic “springback” or coil expansion from stress relaxation, the winding diameter/pitch, and the processing parameters used to set the coil shape. In one embodiment, a coiled cable is more resistant to flex fatigue compared to a linear or straight cable. Additionally, smaller coiled cable diameters are achieved through application of the principles described herein. In one embodiment, about 10 percent or more of a diameter reduction in the coiled conductive element is achieved through the principles described herein. In another embodiment, about 5 percent or more diameter reduction is achieved in the coiled conductive element through the principles described herein. In still yet another embodiment, about 2 percent or more diameter reduction is achieved in the coiled conductive element through the principles described herein. Smaller coiled cable diameters allow for smaller sized leads to be produced. Smaller sized leads can include 7 French or smaller. In another embodiment, smaller sized leads can include 6 French or smaller. In still yet another embodiment, smaller sized leads can include 5 French or smaller.

The principles described herein are applicable to all types of medical electrical leads. For example, the disclosure applies to cardiovascular leads (e.g. high voltage leads, low voltage leads etc.), neurological leads, or other suitable applications.

FIG. 1 depicts a medical device system 100. A medical device system 100 includes a medical device housing 102 having a connector module 104 (e.g. international standard (IS)-1, defibrillation (DF)-1, IS-4 etc.) that electrically couples various internal electrical components housed in medical device housing 102 to a proximal end 105 of a medical electrical lead 106. A medical device system 100 may comprise any of a wide variety of medical devices that include one or more medical lead(s) 106 and circuitry coupled to the medical electrical lead(s) 106. An exemplary medical device system 100 can take the form of an implantable cardiac pacemaker, an implantable cardioverter, an implantable defibrillator, an implantable cardiac pacemaker-cardioverter-defibrillator (PCD), a neurostimulator, a tissue and/or muscle stimulator. IMDs are implanted in a patient in an appropriate location. Exemplary IMDs are commercially available as including one generally known to those skilled in the art, such as the Medtronic CONCERTO™, SENSIA™, VIRTUOSO™, RESTORE™, RESTORE ULTRA™, sold by Medtronic, Inc. of Minnesota. Non-implantable medical devices or other types of devices may also utilize batteries such as external drug pumps, hearing aids and patient monitoring devices or other suitable devices. Medical device system 100 may deliver, for example, pacing, cardioversion or defibrillation pulses to a patient via electrodes 108 disposed on distal end 107 of one or more lead(s) 106. Specifically, lead 106 may position one or more electrodes 108 with respect to various cardiac locations so that medical device system 100 can deliver electrical stimuli to the appropriate locations.

FIG. 2 depicts lead 106. Lead 106 includes a lead body 117 that extends from proximal end 105 to a distal end 107. Lead body 117 can include one or more connectors 101, and one or more jacketed conductive elements 112a-d. A jacket (also referred to as a liner, longitudinal element, coating) extends along and longitudinally around the conductive elements 112a-d and can serve to contain or mechanically constrain one or more conductive elements 112a-d. A jacket can also insulate one or more conductive elements 112a-d. Connector module 104 can contain connectors 122, such as set screws, serve to electrically and mechanically connect conductive elements 112a-d to ports (not shown) of connector module 104. Conductive element 112c (also referred to as a “conductor coil,” torque coil”, “distal tip conductor”) can extend to the distal end 107 and can optionally be coupled to a retractable and/or extendable helical tip. One or more conductive elements 112a,b serve as, or are connected to, defibrillation coils 103a,b that deliver electrical stimuli, when necessary, to tissue of a patient. Lead 106 can also include a conductive element 112d that extends from the proximal end 105 to ring electrode 118 while another conductive element 112c extends from proximal end 105 to tip electrode 120.

Electrically conductive elements 112a-d can include coils, wires, coil wound around a filament, cables, conductors or other suitable members. Conductive elements 112a-d can comprise platinum, platinum alloys, titanium, titanium alloys, tantalum, tantalum alloys, cobalt alloys (e.g. MP35N, a nickel-cobalt alloy etc.), copper alloys, silver alloys, gold, silver, stainless steel, magnesium-nickel alloys, palladium, palladium alloys or other suitable materials. Electrically conductive element 112a-d is covered, or substantially covered, longitudinally with a jacket 130 (also referred to as a liner, a longitudinal element, a longitudinal member, a coating, a tubular element, a tube or a cylindrical element). In yet another embodiment, each conductive element 112a-d is surrounded by a tubular element, which can possess a circular or a non-circular cross-section. An outercover or outerjacket in a lead body 117 can exhibit a non-circular cross-section.

Typically, the outer surface of electrodes 108 such as the ring electrode 118, the tip electrode 120, and the defibrillation coils 103a,b are exposed or not covered by a jacket 130 or liner so that electrodes 108 can sense and/or deliver electrical stimuli to tissue of a patient. A sharpened distal tip (not shown) of tip electrode 120 facilitates fixation of the distal end of helically shaped tip electrode 120 into tissue of a patient.

Referring to FIGS. 3A-3B, and 4A-4B, lead body 117 can include one or more jackets 130 and one or more conductive elements 112a,b,d. In one embodiment, lead body 117 comprises one or more jackets 130 disposed in another jacket 130. In still yet another embodiment, lead body 117 comprises one or more jackets 130 with an outer cover 140 that surrounds the one or more jackets 130.

Each jacket 130 can include one or more covers, as depicted in FIGS. 4A-4B with cross-sectional segment 128. Each cover 146, 148, 150, and 152 can comprise one or more layers of polymeric compounds. Numerous embodiments of jacket 130 or liner are summarized in Table 1 and described in greater detail below. The first embodiment listed in Table 1 involves a single cover or first cover 144 of PEEK such that the inner lumen of first cover 144 is adjacent to a conductive element 112 a,b,d, a delivery device (not shown) such as a guide wire or stylet, or a lumen without a delivery device, or a conductive element 112c such as a conductor coil. PEEK is commercially available as Optima from Invibio located in Lancashire, United Kingdom. The first cover 144 of PEEK can be formed in a variety of ways. In one embodiment, the single cover or first cover of PEEK may be introduced or applied directly over a conductive element 112a-d through extrusion. Extrusion is the process of forming a continuous shape by applying force to a material through a die. Polymer extrusion is described, for example, in Chris Rauwendaal, pp. 1-30, 155-205, Polymer Extrusion (4th ed. 2001), which is incorporated by reference in relevant part. Generally, the polymeric material is heated in a barrel of the extruder until it attains or exceeds its melt temperature. Thereafter, the polymeric material is simultaneously extruded through a die of the extruder over the conductive element 112a-d while the conductive element 112a-d continues to move away from the extruder and/or the conductive element 112a-d moves radially. The polymeric material then forms into a first cover 144 (also referred to as first longitudinal element) over the conductive element 112a-d. After formation of first cover 144, the polymeric material is allowed to cool. There are numerous ways to cool the polymeric material. For example, the first cover 144 can be air cooled, which is a slow cooling process. Alternatively, the first cover 144 can be placed in a cool water bath. In yet another embodiment, the first cover 144 and the conductive element 112a-d can be placed into a cooler such as a refrigeration unit to quickly cool the polymeric material. The process of extruding polymeric material and allowing the polymeric material applies to each embodiment listed below.

The cover of PEEK can have a thickness of about 0.0005 inches to about 0.0015 inches. In another embodiment, the cover of extruded PEEK can possess a thickness that ranges from about 0.00020 inches to about 0.0012 inches. In yet another embodiment, he cover of PEEK has a thickness of about 0.0005 inches to about 0.0020 inches. The PEEK in combination with the conductive element 112a-d forms a composite structure. The composite structure is then formed into a coil shape. In one embodiment, the composite structure is formed into a coil through, for example, winding the conductive element 112a, b,d over a mandrel 702, a cylindrically shaped element, exemplarily depicted in FIG. 10A. In particular, the mandrel 702 can be a high tensile strength wire that is held under tension (i.e. both ends of the mandrel 702 are clamped) while the filars of the coil are wound around the diameter of the mandrel 702. While the mandrel 702 continues to rotate or move radially, filars of the coil are being wound or served around mandrel 702. The filars are simultaneously translated along mandrel 702 while being wound about mandrel 702. An exemplary amount of winding tension applied is about 15 grams; however, it is appreciated that other amounts of winding tensions can be used The amount of tension used can depend upon the geometry and/or the mechanical characteristics (e.g. break load or strength of the cable filars, yield strength of the cable filars, etc.) of the cable filars that are to be formed. Coil winding equipment is commercially available from Accuwinder Engineering Company located in San Dimas, Calif.

The coiled conductive element 112a, b,d can be mechanically constrained to minimize or eliminate diametrical and/or axial expansion of the coiled conductive element 112a, b,d. Exemplary methods for mechanically constraining the conductive element 112a,b,d can include clamping or bonding the proximal and distal ends of 112a,b,d to a mandrel 702 or other suitable fixture or component. The clamp(s) or clamp mechanism(s) can mechanically constrain or secure the coiled conductive element 112a,b,d against the mandrel 702, as depicted, for example, in FIG. 10 such that coiled conductive element 112a,b,d will not rotate or expand diametrically and/or axially. Exemplary clamping mechanisms can take the form of a mechanical clamp, toggle(s) or heat shrink tubing(s). The clamping mechanism can mechanically constrain the coil conductive element on the mandrel and hold the coiled conductive element in place during subsequent operations.

In one embodiment, after the extrusion coating process and the coiling process, no thermal processing is performed on the coiled conductive element 112a, b,d. In another embodiment, after the extrusion coating process and the coiling process, thermal processing is performed on the coiled conductive element 112a, b,d. In still yet another embodiment, after the extrusion coating process, thermal processing is performed on the conductive element 112a, b,d which is thereafter followed by a coiling process to coil the conductive element 112a, b,d. In yet another embodiment, after the extrusion coating process, the coiled conductive element 112a, b,d is thermal processed and can then undergo a coiling process. After coiling process, the coiled conductive element 112a, b,d undergoes a second thermal process.

The composite structure can then undergo a thermal process; however, it is appreciated that a thermal process may be unnecessary to form, for example, a coiled cable assembly. In one embodiment, the composite structure is placed or run through a chamber. For example, a chamber or oven, commercially available from Despatch Industries, Minneapolis, Minn., can be used to process the composite structure. In one embodiment, the temperature in the chamber is about 130° C. to about 210° C. In one embodiment, the temperature in the chamber is about 130° C. to about 210° C. The composite structure remains at this temperature for about 30 seconds to about 45 minutes and then is cooled to form the ETFE polymeric material and conductive element 112a,b,d in its coiled shape. The mechanical constraint is then removed such as through de-clamping or cutting the proximal and distal ends of the conductive element 112 from the mandrel.

The first embodiment listed in Table 1 relates to a jacket 130 formed of a first cover 144. First cover 144 of ethylene-tetrafluoroethylene (ETFE) can possess a thickness that ranges from about 0.0005 inches to about 0.0015 inches of extruded ETFE. In another embodiment, first cover 144 can possess a thickness that ranges from about 0.00020 inches to about 0.003 inches. A composite structure is composed of the first cover 144 over the conductive element 112a,b,d. The composite structure is formed into a coil shape and then mechanically constrained, as previously described.

The composite structure then undergoes thermal annealing or stress relieving in a chamber. The temperature in the chamber is about 130° C. to about 210° C. for about 30 seconds to about 30 minutes to allow the polymeric material to form jacket 130 around conductive element 112a,b,d. Thereafter, the mechanical constraint is removed.

The second embodiment listed in Table 1 relates to a jacket 130 formed of a first, and second covers 144, 146. First cover 144 of ETFE can possess a thickness that ranges from about 0.0005 inches to about 0.0015 inches of extruded ETFE. In another embodiment, first cover 144 can possess a thickness that ranges from about 0.00020 inches to about 0.003 inches. In another embodiment, first cover 144 can possess a thickness that ranges from about 0.00020 inches to about 0.001 inches. First cover 144 of ETFE is formed by extruding the ETFE over a conductive element 112a,b,d. After the first cover 144 of ETFE has been formed, a second cover 146 of ETFE is introduced over the first cover 144. Second cover 146 can possess a thickness that ranges from about 0.00020 inches to about 0.001 inches. A composite structure is composed of the first, and second covers 144, 146 respectively, over the conductive element 112a,b,d. The composite structure is formed into a coil shape and then mechanically constrained, as previously described.

The composite structure then undergoes thermal annealing or stress relieving in a chamber. The temperature in the chamber is about 130° C. to about 210° C. for about 30 seconds to about 30 minutes to allow the polymeric material to form jacket 130 around conductive element 112a,b,d. Thereafter, the mechanical constraint is removed.

The third embodiment listed in Table 1 relates to a jacket 130 formed of a first, second and third covers 144, 146, 148. First cover 144 of ETFE can possess a thickness that ranges from about 0.0005 inches to about 0.0015 inches of extruded ETFE. In another embodiment, first cover 144 can possess a thickness that ranges from about 0.00020 inches to about 0.001 inches. First cover 144 of ETFE is formed by extruding the ETFE over a conductive element 112a,b,d. After the first cover 144 of ETFE has been formed, a second cover 146 of ETFE is introduced over the first cover 144. Second cover 146 can possess a thickness that ranges from about 0.00020 inches to about 0.001 inches. A third cover 148 of ETFE is introduced over the second cover 146 in which the third cover 148 can possess a thickness that ranges from about 0.00020 inches to about 0.001 inches. A composite structure is composed of the first, second, and third covers 144, 146, 148 respectively, over the conductive element 112a,b,d. The composite structure is formed into a coil shape and then mechanically constrained, as previously described.

The composite structure then undergoes thermal annealing or stress relieving in a chamber. The temperature in the chamber is about 130° C. to about 210° C. for about 30 seconds to about 30 minutes to allow the polymeric material to form jacket 130 around conductive element 112a,b,d. Thereafter, the mechanical constraint is removed.

The fourth embodiment listed in Table 1 involves a first cover 144 of ETFE followed by a second cover 146 of fluorinated ethylene propylene (FEP). First cover 144 of ETFE can possess a thickness that ranges from about 0.0005 inches to about 0.0015 inches of extruded ETFE. In another embodiment, first cover 144 can possess a thickness that ranges from about 0.00020 inches to about 0.001 inches. After the first cover 144 of ETFE has been formed, a second cover 146 of FEP is introduced over the first cover 144. Second cover 146 can possess a thickness that ranges from about 0.00020 inches to about 0.001 inches. In another embodiment, second cover 146 can possess a thickness that ranges from about 0.00020 inches to about 0.003 inches. The composite structure, comprised of the first and second covers 144, 146 over the conductive element 112a,b,d, is formed into a coil shape and then mechanically constrained.

Thereafter, the composite structure undergoes thermal annealing or stress relieving in a chamber, as previously described. The temperature of the chamber is about 130° C. to about 210° C. for about 30 seconds to about 30 minutes to allow the polymeric material to form jacket 130 over conductive element 112a,b,d, after which time the mechanical constraint is removed.

The fifth embodiment listed in Table 1 relates to a jacket 130 formed of a first, second and third covers 144, 146, 148. First cover 144 of ETFE can possess a thickness that ranges from about 0.0005 inches to about 0.0015 inches of extruded ETFE. In another embodiment, first cover 144 can possess a thickness that ranges from about 0.00020 inches to about 0.001 inches. First cover 144 of ETFE is formed by extruding the ETFE over a conductive element 112a,b,d. After the first cover 144 of ETFE has been formed, a second cover 146 of ETFE is introduced over the first cover 144. Second cover 146 can possess a thickness that ranges from about 0.00020 inches to about 0.001 inches. A third cover 148 of FEP is introduced over the second cover 146 in which the third cover 148 can possess a thickness that ranges from about 0.00020 inches to about 0.001 inches. A composite structure is composed of the first, second, and third covers 144, 146, 148 respectively, over the conductive element 112a,b,d. The composite structure is formed into a coil shape and then mechanically constrained, as previously described.

The composite structure then undergoes thermal annealing or stress relieving in a chamber. The temperature in the chamber is about 130° C. to about 210° C. for about 30 seconds to about 30 minutes to allow the polymeric material to form jacket 130 around conductive element 112a,b,d. Thereafter, the mechanical constraint is removed.

The sixth embodiment listed in Table 1 involves a first cover 144 of ETFE followed by a second cover 146 of FEP. First cover 144 of ETFE can possess a thickness that ranges from about 0.0005 inches to about 0.0015 inches of extruded ETFE. In another embodiment, first cover 144 can possess a thickness that ranges from about 0.00020 inches to about 0.001 inches. After the first cover 144 of ETFE has been formed, a second cover 146 of perfluoroalkoxy (PFA) is introduced over the first cover 144. Second cover 146 can possess a thickness that ranges from about 0.00020 inches to about 0.001 inches. In another embodiment, second cover 146 can possess a thickness that ranges from about 0.00020 inches to about 0.003 inches. The composite structure, comprised of the first and second covers 144, 146 over the conductive element 112a,b,d, is formed into a coil shape and then mechanically constrained.

Thereafter, the composite structure undergoes thermal annealing or stress relieving in a chamber, as previously described. The temperature of the chamber is about 130° C. to about 210° C. for about 30 seconds to about 30 minutes to allow the polymeric material to form jacket 130 over conductive element 112a,b,d, after which time the mechanical constraint is removed.

The seventh embodiment listed in Table 1 relates to a jacket 130 formed of a first, second and third covers 144, 146, 148. First cover 144 of ETFE can possess a thickness that ranges from about 0.0005 inches to about 0.0015 inches of extruded ETFE. In another embodiment, first cover 144 can possess a thickness that ranges from about 0.00020 inches to about 0.001 inches. First cover 144 of ETFE is formed by extruding the ETFE over a conductive element 112a,b,d. After the first cover 144 of ETFE has been formed, a second cover 146 of ETFE is introduced over the first cover 144. Second cover 146 can possess a thickness that ranges from about 0.00020 inches to about 0.001 inches. A third cover 148 of PFA is introduced over the second cover 146 in which the third cover 148 can possess a thickness that ranges from about 0.00020 inches to about 0.001 inches. A composite structure is composed of the first, second, and third covers 144, 146, 148 respectively, over the conductive element 112a,b,d. The composite structure is formed into a coil shape and then mechanically constrained, as previously described.

The composite structure then undergoes thermal annealing or stress relieving in a chamber. The temperature in the chamber is about 130° C. to about 210° C. for about 30 seconds to about 30 minutes to allow the polymeric material to form jacket 130 around conductive element 112a,b,d. Thereafter, the mechanical constraint is removed.

The eighth embodiment listed in Table 1 relates to a jacket 130 formed of a first cover 144. First cover 144 of polyfluorotetraethylene (PTFE) such as PTFE (extruded and nonporous) can possess a thickness that ranges from about 0.0005 inches to about 0.0015 inches of extruded ETFE. In another embodiment, first cover 144 can possess a thickness that ranges from about 0.00020 inches to about 0.003 inches. A composite structure is composed of the first cover 144 over the conductive element 112a,b,d. The composite structure is formed into a coil shape and then mechanically constrained, as previously described.

The composite structure then undergoes thermal annealing or stress relieving in a chamber. The temperature in the chamber is about 130° C. to about 210° C. for about 30 seconds to about 30 minutes to allow the polymeric material to form jacket 130 around conductive element 112a,b,d. Thereafter, the mechanical constraint is removed.

The ninth embodiment listed in Table 1 relates to a jacket 130 formed of a first, and second covers 144, 146. First cover 144 of PTFE (extruded and nonporous) can possess a thickness that ranges from about 0.0005 inches to about 0.0015 inches of extruded PTFE (extruded and nonporous). Unlike other polymers, PTFE is not melt-processable. Fully dense or non-porous PTFE can be produced via a “paste extrusion” process. With this process a very fine PTFE resin is mixed with a hydrocarbon extrusion aid (e.g. mineral spirits etc.) and compressed to form a billet called a preform, which is “ram extruded” at high pressures. The resulting extruded form is then thermally treated to remove the extrusion aid and sinter the fine particles of PTFE together.

In another embodiment, first cover 144 can possess a thickness that ranges from about 0.00020 inches to about 0.003 inches. In another embodiment, first cover 144 can possess a thickness that ranges from about 0.00020 inches to about 0.001 inches. First cover 144 of PTFE (extruded and nonporous) is formed by extruding the PTFE (extruded and nonporous) over a conductive element 112a,b,d. After the first cover 144 of PTFE (extruded and nonporous) has been formed, a second cover 146 of PTFE (extruded and nonporous) is introduced over the first cover 144. Second cover 146 can possess a thickness that ranges from about 0.00020 inches to about 0.001 inches. A composite structure is composed of the first, and second covers 144, 146 respectively, over the conductive element 112a,b,d. The composite structure is formed into a coil shape and then mechanically constrained, as previously described.

The composite structure then undergoes thermal annealing or stress relieving in a chamber. The temperature in the chamber is about 130° C. to about 210° C. for about 30 seconds to about 30 minutes to allow the polymeric material to form jacket 130 around conductive element 112a,b,d. Thereafter, the mechanical constraint is removed.

The tenth embodiment listed in Table 1 relates to a jacket 130 formed of a first, second and third covers 144, 146, 148. First cover 144 of PTFE (extruded and nonporous) can possess a thickness that ranges from about 0.0005 inches to about 0.0015 inches of PTFE (extruded and nonporous). In another embodiment, first cover 144 can possess a thickness that ranges from about 0.00020 inches to about 0.001 inches. First cover 144 of PTFE (extruded and nonporous) is formed by extruding the PTFE (extruded and nonporous) over a conductive element 112a,b,d. After the first cover 144 of PTFE (extruded and nonporous) has been formed, a second cover 146 of PTFE (extruded and nonporous) is introduced over the first cover 144. Second cover 146 can possess a thickness that ranges from about 0.00020 inches to about 0.001 inches. A third cover 148 of fluorinated ethylene propylene (FEP) is introduced over the second cover 146 in which the third cover 148 can possess a thickness that ranges from about 0.00020 inches to about 0.001 inches. A composite structure is composed of the first, second, and third covers 144, 146, 148 respectively, over the conductive element 112a,b,d. The composite structure is formed into a coil shape and then mechanically constrained, as previously described.

The composite structure then undergoes thermal annealing or stress relieving in a chamber. The temperature in the chamber is about 130° C. to about 210° C. for about 30 seconds to about 30 minutes to allow the polymeric material to form jacket 130 around conductive element 112a,b,d. Thereafter, the mechanical constraint is removed.

The eleventh embodiment listed in Table 1 relates to a jacket 130 formed of a first, second and third covers 144, 146, 148. First cover 144 of PTFE (extruded and nonporous) can possess a thickness that ranges from about 0.0005 inches to about 0.0015 inches of PTFE (extruded and nonporous). In another embodiment, first cover 144 can possess a thickness that ranges from about 0.00020 inches to about 0.001 inches. First cover 144 of PTFE (extruded and nonporous) is formed by extruding the PTFE (extruded and nonporous) over a conductive element 112a,b,d. After the first cover 144 of PTFE (extruded and nonporous) has been formed, a second cover 146 of PTFE (extruded and nonporous) is introduced over the first cover 144. Second cover 146 can possess a thickness that ranges from about 0.00020 inches to about 0.001 inches. A third cover 148 of PFA is introduced over the second cover 146 in which the third cover 148 can possess a thickness that ranges from about 0.00020 inches to about 0.001 inches. A composite structure is composed of the first, second, and third covers 144, 146, 148 respectively, over the conductive element 112a,b,d. The composite structure is formed into a coil shape and then mechanically constrained, as previously described.

The composite structure then undergoes thermal annealing or stress relieving in a chamber. The temperature in the chamber is about 130° C. to about 210° C. for about 30 seconds to about 30 minutes to allow the polymeric material to form jacket 130 around conductive element 112a,b,d. Thereafter, the mechanical constraint is removed.

The tenth embodiment listed in Table 1 relates to a jacket 130 formed of a first, second and third covers 144, 146, 148. First cover 144 of PTFE (extruded and nonporous) can possess a thickness that ranges from about 0.0005 inches to about 0.0015 inches of PTFE (extruded and nonporous). In another embodiment, first cover 144 can possess a thickness that ranges from about 0.00020 inches to about 0.001 inches. First cover 144 of PTFE (extruded and nonporous) is formed by extruding the PTFE (extruded and nonporous) over a conductive element 112a,b,d. After the first cover 144 of PTFE (extruded and nonporous) has been formed, a second cover 146 of PTFE (extruded and nonporous) is introduced over the first cover 144. Second cover 146 can possess a thickness that ranges from about 0.00020 inches to about 0.001 inches. A third cover 148 of ethylene-tetrafluoroethylene based copolymer (EFEP) is introduced over the second cover 146 in which the third cover 148 can possess a thickness that ranges from about 0.00020 inches to about 0.001 inches. A composite structure is composed of the first, second, and third covers 144, 146, 148 respectively, over the conductive element 112a,b,d. The composite structure is formed into a coil shape and then mechanically constrained, as previously described.

The composite structure then undergoes thermal annealing or stress relieving in a chamber. The temperature in the chamber is about 130° C. to about 210° C. for about 30 seconds to about 30 minutes to allow the polymeric material to form jacket 130 around conductive element 112a,b,d. Thereafter, the mechanical constraint is removed.

Table 1, presented below, summarizes the various embodiments of jacket 130.

TABLE 1
Embodiments of jacket 130 that comprise
one or more polymeric compounds
No.First CoverSecond CoverThird CoverN Cover
1ETFE
2ETFEETFE
3ETFEETFEETFE
4ETFEFEP
5ETFEETFEFEP
6ETFEPFA
7ETFEETFEPFA
8PTFE
(extruded,
nonporous)
9PTFEPTFE (extruded,
(extruded,nonporous)
nonporous)
10PTFEPTFE (extruded,FEP
(extruded,nonporous)
nonporous)
11PTFEPTFE (extruded,PFA
(extruded,nonporous)
nonporous)
12PTFEPTFE (extruded,EFEP
(extruded,nonporous)
nonporous)

The insulated conductive element formed through jacket 130 over conductive element 112a,b,d can be helically wrapped around a mandrel (not shown). After winding the insulated cable onto the mandrel and mechanically restraining this composite structure, the polymeric material over the conductive element (e.g. cable etc.) can be annealed to minimize springback and allow the conductive element (e.g. cable etc.) to retain its coiled shape. After being removed from the mandrel, the conductive element (e.g. cable etc.) retains its coiled shape.

Insulated conductive element 200 is depicted in FIGS. 5A-5B. Insulated conductive element 200 includes a conductive element 112a,b,d (i.e. cable, coiled cable etc.) with a thin polymeric material 204 or cover that has been thermally processed (e.g. annealed etc.) to conductive element 112a,b,d. Polymeric material 204 comprises a first and second covers 124a,124b. Conductive element 112a,b,d has an outer diameter of about 0.09 inches or less. In one embodiment, conductive element 112a,b,d can be a 1×19 cable construction with filaments composed of MP35N/Ag core.

Referring to FIGS. 6A-6B, an insulated conductive element 300 is depicted that comprises a set of conductors 302a-c (i.e. three conductors) and an insulative layer or cover 304. Conductive element 300 such as a 1×19 cable MP35N/Ag core and has an outer diameter of about 0.055 inches. Insulative layer 304 comprises a layer of PEEK and a layer of ETFE. In one embodiment, each layer of PEEK and ETFE is about 0.0008 inches or less. In another embodiment, each layer of PEEK and ETFE is about 0.002 inches or less.

Referring to FIG. 7A-7B, insulated conductive element 400 comprises a set of conductors 402a-e (i.e. five conductors) and an insulative layer or cover 404. Conductive element 400 has an outer diameter of about 0.060 inches and is a 1×19 cable. Insulative layer 404 comprises a layer of PEEK and a layer of ETFE. In one embodiment, each layer of PEEK and ETFE is about 0.0008 inches or less. In another embodiment, each layer of PEEK and ETFE is about 0.002 inches or less.

Referring to FIGS. 8A-8C, jacketed conductive element 500 is shown as retaining its coiled shape despite being stretched. Conductive element 500 comprises a 1×19 cable construction with filaments composed of MP35N/Ag core with an insulative or jacketed layer, coating or cover. The insulative layer comprises a layer of PEEK and a layer of ETFE. In one embodiment, each layer of PEEK and ETFE is about 0.0008 inches or less. In one embodiment, each layer of PEEK and ETFE is about 0.002 inches or less. Referring to FIG. 8A, insulated conductive element 500 is depicted in a relaxed position (FIG. 8A) over a mandrel. While over the mandrel, conductive element 500 is thermally annealed. Referring to FIG. 8B, insulated conductive element 500 is depicted in a stretched position. Thereafter, insulated conductive element 500 moves to a relaxed position after being stretched (FIG. 8C). The insulated conductive element 500 retains 99% or more of its original coiled shape. In another embodiment, insulated conductive element 500 comprises 95% or more of its original coiled shape.

Referring to FIG. 9, insulated conductive element 600 is helically wrapped around a coil liner 130. Insulated conductive element 600 comprises a set of jacketed conductors 602 (i.e. five conductors cable-coil). Referring to FIG. 10A-10B, insulated conductive element 700 is helically wrapped around a mandrel 702. Insulated conductive element 700 comprises a set of conductors 702 (i.e. five conductors) and an insulative layer or cover.

FIG. 11 is a flow diagram of an exemplary computer-implemented method or a manual process to form at least one cover of PEEK over the conductive element. At block 800, a counter, x, is initiated to 1 in order to count the number polymer covers formed over a conductive element. At block 810, a polymer is extruded (also referred to as introduced) over the conductive element. Polymers with high elastic modulus (i.e. stiffness) such as PEEK are preferred since PEEK can be annealed or stress relieved to increase crystallinity and set the coil shape in conductive element 112a-c. At block 820, the polymer cover can undergo an optional thermal process.

At block 830, the counter, X, is incremented by adding 1 to the previous value of X. At block 840, a determination is made as to whether a sufficient number of polymer covers have been formed over the conductive element. In this embodiment, a determination is made as to whether X=N where N equals the number of pre-selected covers to be added to the conductive element. If X does not equal N, the process control returns to block 810 to extrude the same or different polymer over the previous polymer cover. If x does equal N, then the process goes to block 850, where the jacketed conductive element undergoes coiling, as previously described. If x does not equal N, the process returns to introducing another polymeric cover over the conductive element 112a-d. If x does equal N, no additional polymer covers are introduced over the conductive element 112a-d. At block 850, the jacketed conductive element is formed into a coil. At block 860, the coiled jacketed conductive element can undergo an optional thermal process. If the method is implemented on a computer, the number of polymeric covers formed over the conductive element and/or the types of polymeric material used for each cover can be displayed on a graphical user interface of a computer. The computer-implemented instructions are executed on a processor of a computer.

FIG. 12 depicts a distal portion of another lead body 900 that includes at least one profile-shaped longitudinal element, which provides channels for placement of one or more elongate conductive elements, and maintains physical and electrical isolation of each elongate conductive element. If the profile-shaped longitudinal element is bonded to the outer insulative tubular longitudinal element at the top of the profile features such as at each rib or protruding end, the resulting lead body 900 is effectively a multilumen construction which can possess a reduced diameter compared to lead bodies utilizing extruded multilumen tubing. The profile-shaped longitudinal element in lead body 900 can also provide enhanced kink resistance and flexibility compared with lead bodies utilizing non-profiled shaped longitudinal elements.

Lead body 900 can include an elongated longitudinal element 930 and one or more elongated conductive elements 112a-f (e.g. cable, coil etc.). Conductive elements 112a-f, also referred to as first, second, third, fourth, and a Nth conductive elements, where N is a whole number, can be individually disposed in polymeric longitudinal elements 930.

A longitudinal element 930, which extends along and longitudinally around the conductive elements 112a-f, can serve to contain or mechanically constrain one or more conductive elements 112a-f. Longitudinal element 930 can also insulate one or more conductive elements 112a-f. Longitudinal element 930 (also referred to as a liner, jacket, coating etc.) can comprise at least one profiled-shaped longitudinal element 904c formed from an extrusion process. In another embodiment, as depicted, longitudinal element 930 can include at least one profiled longitudinal element 904c along with one or more other covers 904a,b,d.

Longitudinal element 930 can be formed by extruding a polymeric material, selected from Table 1, such as PEEK, over a mandrel. For example, after the polymeric material is heated in the barrel of the extruder until it attains or exceeds its melt temperature, the polymeric material is simultaneously extruded through a die of the extruder over the mandrel while the mandrel continues to move away from the extruder and/or the mandrel moves radially. The polymeric material then forms into a first cover 904b (also referred to as first longitudinal element) over the mandrel. After formation of first cover 904b, the polymeric material is allowed to cool. There are numerous ways to cool the polymeric material. For example, the first cover 904b can be air cooled, which is a slow cooling process. Alternatively, the first cover 904b can be placed in a cool water bath. In yet another embodiment, the first cover 904b and the mandrel can be placed into a cooler such as a refrigeration unit to quickly cool the polymeric material.

After the first cover 904b has cooled, a second cover 904c is formed through a second extrusion process. The polymeric material is extruded through another die over the first cover 904b. The second cover 904c (also referred to as a second longitudinal element) is allowed to cool in a manner, as previously described. As depicted, in one embodiment, second cover 904c can comprise a longitudinal tube 908 with a set of elongated protruding ends 907 or ribs extending from the longitudinal tube. Second cover 904c, comprising longitudinal tube 908 with a set of elongated protruding ends 907, is a single extruded piece or element. Recessed regions 910 are located between each protruding end 907. In one embodiment, recessed regions 910 extend from the proximal to the distal end of the lead body.

In one embodiment, protruding ends 907 are substantially rounded. In another embodiment, protruding ends 907 are depicted as being substantially cylindrically shaped with rounded ends.

After second cover 904c has cooled, a set of lined or insulated conductive elements 112a-f, are helically served or wound within recessed areas 912 disposed between protruding ends 907. Serving or winding insulated conductive elements 112a-f into recessed areas 912 can be performed manually or automatically through a winding machine while optionally simultaneously introducing third cover 904d (also referred to as third longitudinal element, outer cover or overlay). In one embodiment, third cover 904d is extruded over insulated conductive elements 112a-f. Third cover 904d is then allowed to cool in a manner as previously described. In another embodiment, third cover 904d is produced or formed separately via extrusion and slid over insulated conductive elements 112a-f. In yet another embodiment, the polymeric material, selected from Table 1, is wrapped or served over insulated conductive elements 112a-f. The mandrel is then removed from jacket 930, which leaves a longitudinal lumen 905 in lead body 900 that can extend from the proximal to the distal ends of the lead body 900. Lumen 905 can remain empty or employed to house a coil or a delivery device.

A variety of different profile-shaped longitudinal elements can be formed through the principles described herein, as exemplified by lead body 1000 depicted in FIGS. 13A-13B. Lead body 1000 can include longitudinal elements 1114, 1116, and 1118, (also referred to as liners, tubular elements, etc.) one or more insulated conductive elements 1004a, with lumen 1120 extending the length of lead body 1000. Profile-shaped longitudinal element 1114 or cover, formed through the extrusion process previously described, comprises a tubular body with a plurality of flared protruding ends 1006 that extend seamlessly therefrom. Profile-shaped longitudinal element 1114 can possess an diameter D1 that can range from about 0.04 inches to about 0.060 inches, D2 that can range from about 0.030 inches to about 0.050 inches, and inner diameter, D3, can range from about 0.020 inches to about 0.040 inches.

Protruding ends 1006, formed as part of profile-shaped longitudinal element 1114, serve to separate elongated insulated conductive elements 112a-f from each other. Protruding ends 1006 extend from a proximal position 1008 to a distal position 1010 from longitudinal element 1114. Protruding end 1006 can possess a height that ranges from about 0.005 inches to about 0.015 inches. In one embodiment, the flared protruding ends 1006 can possess a distal end that can extend 2a between first and second sides 1012, 1014, respectively, which is about 90 degrees or less. In another embodiment, the flared protruding ends 1006 can possess a distal end that can extend 2a between first and second sides 1012, 1014, respectively, which is about 60 degrees or less. In still yet another embodiment, the flared protruding ends 1006 can possess a distal end that can extend 2a between first and second sides 1012, 1014, respectively, which is about 45 degrees or less. In another embodiment, longitudinal element 1114 can include one or more protruding ends 1106, depicted in FIG. 13C. Protruding ends 1106 can possess a distal end that can extend 2a between first and second sides 1112, 1114, respectively, which is about 90 degrees or less.

In this embodiment, the profiled-shaped cover is extruded over either a mandrel or a conductive element 112a-f. In this embodiment, the profiled-shaped cover is extruded over a mandrel. Thereafter, insulated conductive elements 112a-f are served between the recessed regions between each flared protruding ends 1006. Thereafter two additional covers are formed over profiled-shaped cover through, for example, extrusion, wrapping or other suitable means.

Co-pending U.S. patent application Ser. No. ______ entitled “MEDICAL ELECTRICAL LEAD” (Attorney docket number P0030357.00) filed by Gregory A. Boser and Kevin R. Seifert and assigned to the same Assignee as the present invention. This co-pending application is hereby incorporated herein by reference in its entirety.

Co-pending U.S. patent application Ser. No. ______ entitled “MEDICAL ELECTRICAL LEAD” (Attorney docket number P0030139.00) filed by Gregory A. Boser and Kevin R. Seifert and assigned to the same Assignee as the present invention. This co-pending application is hereby incorporated herein by reference in its entirety.

Co-pending U.S. patent application Ser. No. ______ entitled “MEDICAL ELECTRICAL LEAD” (Attorney docket number P0033694.00) filed by Gregory A. Boser and Kevin R. Seifert and assigned to the same Assignee as the present invention. This co-pending application is hereby incorporated herein by reference in its entirety.

The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.