Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
  • A61N1/00—Electrotherapy; Circuits therefor
  • A61N1/02—Details
  • A61N1/04—Electrodes
  • A61N1/05—Electrodes for implantation or insertion into the body, e.g. heart electrode
  • A61N1/0551—Spinal or peripheral nerve electrodes
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
  • A61N1/00—Electrotherapy; Circuits therefor
  • A61N1/02—Details
  • A61N1/04—Electrodes
  • A61N1/05—Electrodes for implantation or insertion into the body, e.g. heart electrode
  • A61N1/0551—Spinal or peripheral nerve electrodes
  • A61N1/0553—Paddle shaped electrodes, e.g. for laminotomy

Definitions

• the present invention is related to spinal cord stimulation therapy and more particularly to medical electrical leads for delivering the stimulation therapy.
• BACKGROUND Electrical stimulation of a spinal cord, which induces pain-relieving paresthesia, can be provided by implantable systems that include electrodes coupled to elongate electrical leads. Such electrodes may be percutaneously or surgically introduced into the epidural space surrounding the spinal cord.
• Medical electrical leads which include an array of electrodes provide flexibility for selection from a variety of stimulation patterns upon implantation without having, to physically reposition the lead within the epidural space.
• Such leads, wherein the electrode array is coupled along a body of the lead or along a distal paddle-like termination of the lead body are known in the art. However, there is still a need for new spinal cord lead assembly methods providing improved manufacturing flexibility.
• Figure IA is a plan view of a medical electrical lead, according to some embodiments of the present invention.
• Figure IB is an end view of the lead shown in Figure IA.
• Figure 1C is a section view, through section line D-D of Figure IA.
• Figures 2A-B are a perspective views of the lead shown in Figure IA.
• Figure 3 A is a schematic including a portion of the spinal canal cut away so that the lead of Figure IA may be seen implanted in the epidural space surrounding a spinal cord.
• Figure 3B is an end view of the implanted lead shown in Figure 3 A.
• Figure 4 is a plan view including a partial section of a portion of a lead body assembly, according to some embodiments of the present invention.
• Figures 5A-B are plan views of mating mold halves, which may be used to couple lead bodies, according to some methods of the present invention.
• Figure IA is a plan view of a medical electrical lead 10O 5 according to some embodiments of the present invention.
• Figure IA illustrates lead 100 including a first column 12 of electrodes AE1-AE8 and a second column 14 of electrodes BEl- BE8 coupled to an insulative distal portion 10, which may be formed from silicone rubber; a first lead body A and a second lead body B each extend proximally from distal portion 10 to corresponding connectors 102 and 104.
• each lead body A, B includes a plurality of insulated conductors; each conductor of each of the pluralities of conductors couples a corresponding electrode of electrodes AE1-AE8 and BE1-BE8 to a corresponding connector contact of contacts AC1-AC8 and BC1-BC8, according to methods known to those skilled in the art, which will be described in greater detail below.
• connectors 102 and 104 may either be connected directly to a stimulation device or to an extension, or adaptor, which includes one or two connectors for connection with the stimulation device.
• Figure IA further illustrates a strain relief 15 extending prpximally from distal portion 10 over lead bodies A, B.
• Figure IB is an end view of lead 100; and
• Figure 1C is a section view through section line D-D of Figure IA.
• FIGS IB-C illustrate each of electrodes AEl- AE8 of first column 12 and each of electrodes BE1-BE8 of second column 14 including an approximately planar electrode surface 11 ; each electrode surface 11 of first column 12 is angled toward each electrode surface 11 of second column 14, such that planes (represented by dashed lines in Figure 1 C), which extend along and approximately orthogonally out from each column 12, 14 intersect one another.
• a surface area of each electrode surface 11 is approximately six square millimeters, a longitudinal spacing between each electrode AEl -AE8 and BE1-BE8, within each column 12, 14 is approximately foi ⁇ r millimeters, edge-to-edge, and approximately seven millimeters, center-to-center, and a spacing between columns 12 and 14 is between approximately three and four millimeters, center-to-center, and between approximately one and two millimeters, edge-to-edge.
• Figure IA illustrates each electrode surface 11 of first column 12 longitudinally aligned with the corresponding electrode surface 11 of second column 14, the scope of the present invention is not so limited, and alternate embodiments may include staggered columns of electrode surfaces.
• FIG. 1 further illustrates distal portion 10 including a first surface 13 extending between an inner edge 602 of each electrode surface 11 of first column 12 and an inner edge 604 of each electrode surface 11 of second column 14, and a second surface 16 extending from an outer edge 612 of each electrode surface 11 of first column 12 to an outer edge 614 of each electrode surface 11 of second column 14.
• first surface 13 curves in a concave fashion and second surface 16 extends behind fh * st and second columns 12, 14 and includes an approximately flat portion 17 disposed opposite first and second columns 12, 14.
• Figures 2A-B are perspective views of lead 100, which further illustrate first surface 13 and flat portion 17 of second surface 16.
• distal portion has a length between . approximately sixty millimeters and approximately seventy millimeters, a width between approximately eight and approximately twelve millimeters, and a thickness, defined from flat portion 17 of surface 16 across to first surface 13, of approximately two millimeters; and, surface 13 has a radius of curvature of approximately nine millimeters.
• Figure 1C further illustrates electrodes AE6 and BE6, representative of each electrode of columns 12 and 14, respectively, extending, in a cantilever fashion, laterally away from respective lead bodies A, B, which extend into distal portion 10.
• Each electrode AE1-AE8 and BE1-BE6 may be coupled, as such, for example, by laser welding, directly to the respective conductor within the corresponding lead body A, B 5 or to a conductive ring, which is coupled to the respective conductor and disposed about the corresponding lead body A 5 B.
• surface 11 of each electrode AE1-AE8 and BE1-BE6 protrudes slightly from adjacent portions of surfaces 13, 16, but, according to alternate embodiments, electrode surfaces 11 are flush with adjacent portions of surfaces 13, 16.
• Figure 3 A is a schematic including a portion of the spinal canal cut away so that lead 100 may be seen implanted in the epidural space of a spinal cord 30; and ' Figure 3B is an end view of the implanted lead 100.
• Figures 3A-B illustrate distal portion 10 of lead implanted in the epidural space such that electrode surfaces 11 are in intimate contact with the dura mater 35 surrounding spinal cord 30.
• Methods for implanting surgical spinal cord leads, such as lead 100 are well known to those skilled in the art.
• the pre-formed profile of distal portion 10, along with the angled arrangement of electrode surfaces 11, as described in conjunction with Figure 1C, may greatly enhance the conformance of distal portion 10 about spinal cord 30 such that electrodes 11 contact the dura mater 35, as shown, for relatively efficient stimulation of spinal cord 30.
• the preformed shape of distal portion 10 facilitates the fit of distal portion 10 within the epidural space.
• Figure 4 is a plan view including a partial section of a portion of a lead body assembly 40, according to some embodiments of the present invention.
• Figure 4 illustrates assembly 40 including four conductors 451-454 wotxnd in a coil 45 and each conductor 451-454 coupled to a conductive ring 401-404, respectively, which is, in turn, coupled to an electrode 41-44, respectively.
• Conductors 451-454 are isolated from one another by an overlay of insulation material surrounding each of conductors 451-454, examples of which include, but are not limited to, polyimide, polytetrafluoroethylene (PTFE), and ethylene tetrafluoroethylene (ETFE).
• PTFE polytetrafluoroethylene
• ETFE ethylene tetrafluoroethylene
• each conductor 451-454 is hooked in a slot of the corresponding conductive ring 401-404, and laser welded thereto, and each electrode 41-44, whose active electrode surface is shown facing into the page, is coupled to the corresponding ring 401-404 via a laser weld, for example, as illustrated along line 440.
• conductor 45 extends proximally to a connector, for example, similar to connectors 102 and 104 of Figure IA 5 where each conductor 451-454 is coupled to a corresponding connector contact, for example, in manner similar to that described for rings 401-404.
• FIG. 4 illustrates assembly 40 including only four conductors and electrodes
• lead body A or lead body B, of Figure IA which each include eight conductors and electrodes, may incorporate an assembly constructed in a similar manner to that of assembly 40, but including four additional conductors, rings and electrodes.
• a step of coupling electrodes to rings is performed prior to coupling two of lead body assemblies 40 together.
• conductive rings 401-404 may form electrode surfaces of completed lead assemblies that include assembly 40, and have been originally manufactured for independent use, for example, as percutaneous spinal cord stimulation leads.
• each electrode for example, electrodes 41-44
• Figure 4 further illustrates insulation members 46, 47, 48 and 49 each extending around a portion of coil 45.
• an adhesive for example, silicone medical adhesive, is injected, per arrow C, to fill lumens of members 46, 47, 48 and 49, prior to coupling a two of assemblies 40 together.
• Coupling two of assemblies 40 together may be accomplished by forming a paddle-like insulative member around the pair assemblies 40 either by a transfer or an insert molding method, known to those skilled in the art; the paddle-like member, according to some embodiments is similar to distal portion 10 described in conjunction with Figures 1A-2B.
• Figures 5A-B are plan views of mating mold halves 51 , 53, which may be used to couple lead bodies, via a transfer molding method, after electrodes 41-44 have been coupled to conductors 451-454.
• Figure 5 A illustrates first mold half 51 including a cavity 512 for forming, in conjunction with a cavity 532 of mating mold half 53 shown in Figure 5 B, a paddle-like insulative distal portion, for example, distal portion 10 illustrated in Figures IA- 2B.
• Figure 5 A further illustrates electrode reliefs 514 disposed at locations in cavity 512 to correspond with positions of electrode surfaces of electrodes 41 -44 of each of two assemblies 40 that will be placed between mold halves 51, 53. Reliefs 514 prevent the flow of injected material, for example, MDX silicone rubber, which forms the paddle-like member, into sites corresponding to electrode surfaces of electrodes 41-44, so that the electrode surfaces will not be covered with the insulative material.
• MDX silicone rubber which forms the paddle-like member
• Figure 5B further illustrates mold half 53 including a relief 518 for placement of a sheet of mesh material, which will be embedded within the paddle-like member, for example, as illustrated in Figure 1C where the mesh is denoted by item number 18.
• Mesh 18 may enhance the structural integrity of the coupling of lead bodies A and B by distal portion 10. After the molding process is completed, excess mesh material may be trimmed away about the perimeter of the paddle-like member.
• a profile of cavity 512, in between reliefs 514 may have a convex curvature, for example, to form surface 13, and a profile of cavity 513 may include a flat portion, for example, to form surface 17.

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• Health & Medical Sciences (AREA)
• Neurology (AREA)
• Neurosurgery (AREA)
• Orthopedic Medicine & Surgery (AREA)
• Cardiology (AREA)
• Heart & Thoracic Surgery (AREA)
• Engineering & Computer Science (AREA)
• Biomedical Technology (AREA)
• Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
• Radiology & Medical Imaging (AREA)
• Life Sciences & Earth Sciences (AREA)
• Animal Behavior & Ethology (AREA)
• General Health & Medical Sciences (AREA)
• Public Health (AREA)
• Veterinary Medicine (AREA)
• Electrotherapy Devices (AREA)

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• 2007
  • 2007-01-23 WO PCT/US2007/060907 patent/WO2007127510A1/en active Application Filing
  • 2007-01-23 WO PCT/US2007/060904 patent/WO2007127509A1/en active Application Filing
  • 2007-01-23 EP EP07710272.1A patent/EP2024008B1/de not_active Not-in-force
  • 2007-01-23 EP EP07756404A patent/EP2026873A1/de not_active Withdrawn

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