Seal for lead bore of an implantable medical device

Abstract

A seal for use within a lead bore of an implantable medical device, the seal for forming a seal against an implantable medical lead inserted into the lead bore, the seal including a cylinder that engages a lead body. The cylinder has a contact length with the lead body of at least 0.010" and an average contact pressure of no more than (10 pounds / inch) / (contact length). Sufficient electrical isolation can be achieved even when debris particles are present between the inner cylinder and the lead body, while insertion force remains acceptable.

Description

Technical Field

[0001] The implementation plan involves a seal placed in the lead hole of an implantable medical device. Background Technology

[0002] The lead hole of the implantable medical device includes one or more electrical connectors that form an electrical connection with a corresponding electrical contact on the proximal end of the implantable medical lead's insertion lead hole. A conductor within the implantable medical lead carries electrical signals between the electrical contact and an electrode located near the distal end of the lead. These electrical signals can be stimulation signals delivered to tissue at the distal electrode. Alternatively, these signals can be sensed physiological signals occurring at the distal electrode and delivered to the sensing circuitry of the implantable medical device.

[0003] When carrying stimulation or sensing signals on implantable medical leads, it is useful to electrically isolate the electrical contacts at the proximal end from each other and from the body tissue surrounding the implantable medical device. For example, such isolation facilitates the delivery of signals intended for a given proximal contact and a corresponding distal electrode to those contacts and electrodes, while largely preventing any amount of signal leakage to the body or other proximal contacts at the proximal end of the lead. Similarly, such isolation facilitates the delivery of sensing signals obtained at a given distal electrode to the circuitry of the implantable device corresponding to the proximal contact paired with that distal electrode, while largely preventing any amount of signal leakage to the body or other proximal contacts at the proximal end of the lead. Likewise, it can potentially largely prevent other electrical signals present near the implantable medical device from leaking into the lead hole.

[0004] Electrical isolation is provided through seals within the leadhole of the implantable medical device. These seals are typically present between adjacent electrical connectors within the leadhole and also at the leadhole entrance on the surface of the implantable medical device. These seals typically provide a circumferential protrusion with an opening at its center, the diameter of which is smaller than the lead diameter, such that it makes contact with the lead body at the opening center to provide a seal around the lead body.

[0005] When a seal is formed, radial movement of the lead body stretches the opening in the protrusion, creating a small gap that allows a small amount of bodily fluid to pass through the seal. This lead body movement can occur during implantation or during normal bodily movement by the patient. Additionally, debris can become trapped between the seal and the lead body, creating such gaps. While a small amount of fluid may not always be a concern, in situations where the electrical signal of interest is very small and other nearby signals are large—such as sensing a relatively small neural signal from the brain in the presence of a relatively large cardiac signal near the implanted medical device—a small amount of fluid entering the lead hole can cause sufficient signal leakage to cause problems. Summary of the Invention

[0006] The implementation addresses these and other issues by providing a seal for the implantable medical device, which includes a cylindrical portion that engages the lead body. Instead of a contact point with the lead body created by a radially inward protrusion with a fixed position, the cylindrical portion contacts along the relatively long length of the lead body to establish sufficient electrical isolation, but with a relatively low average contact pressure to avoid high insertion force requirements.

[0007] An embodiment provides an implantable medical system including a lead and a housing defining a lead hole having a lead aperture, wherein the lead is present within the lead hole. Circuitry is present within the housing, and an electrical connector is located within the lead hole and electrically connected to the circuitry. A resilient sealing body is coupled to the housing, and the resilient sealing body includes a first cylinder defining a sealing aperture having a centerline. The first cylinder is located within the lead hole and contacts the lead body over a length exceeding 0.010 inches, with an average contact pressure not greater than (10 psi) / (contact length). A wall portion of the resilient sealing body is coupled to the housing, and the wall portion is coupled to the first cylinder, the first cylinder having a rest position in which the centerline forms a first angle relative to a first plane. The first cylindrical portion is movable relative to the wall portion to allow a change in the first angle of the centerline relative to the first plane.

[0008] An embodiment provides a method for electrically isolating electrical contacts of a therapeutic delivery element within a surrounding structure having a first orifice containing an electrical connector. The method includes providing a resilient sealing body located within the first orifice and coupled to the surrounding structure, the resilient sealing body including a first cylinder defining a sealing orifice configured to receive a portion of the therapeutic delivery element and establish electrical contacts between the therapeutic delivery element and the electrical connector of the first orifice. The method also includes generating contact between the first cylinder and the portion of the therapeutic delivery element over a contact length of at least 0.010 inches when the portion of the therapeutic delivery element is received by the first cylinder, wherein the average contact pressure is not greater than (10 psi) / (contact length).

[0009] One embodiment provides an implantable medical system including a lead having a proximal contact and a lead body. The implantable medical system also includes a lead extension comprising a distal end structure defining a lead aperture containing an electrical connector and at least one resilient sealing body comprising a first cylinder. The lead is present within the lead aperture such that the proximal contact contacts the electrical connector, and wherein the first cylinder contacts the lead body over a contact length of at least 0.010 inches, and the average contact pressure is no greater than (10 psi) / (contact length).

[0010] The embodiments described herein are primarily discussed for the head of an implantable medical device mounted on the housing for receiving the proximal end of a lead. However, this should not be considered limiting. The sealing element can be incorporated into any aspect of an implantable system requiring a sealing element that is movable relative to a wall portion of the sealing element. For example, such a sealing element can also be used at the distal end of a lead extension for receiving the proximal end of the lead. Attached Figure Description

[0011] Figure 1 Examples of implantable medical systems according to various embodiments are shown, which include implantable medical leads and implantable medical devices that may include seals.

[0012] Figure 2 A cross-sectional top view of a first example of a seal is shown, which includes an inner cylinder with a long contact length coupled to a front wall.

[0013] Figure 2A and Figure 2B yes Figure 2 An enlarged cross-sectional view of a seal that traps debris filaments between an inner cylinder and a structure inserted into the inner cylinder.

[0014] Figure 3 A cross-sectional top view of a second example of a seal is shown, which includes an inner cylinder with a long contact length, wherein there is no additional seal beyond the inner cylinder, and wherein the inner cylinder is coupled to the front wall.

[0015] Figure 4 A cross-sectional top view of a third example of a seal is shown, which includes an inner cylinder with a long contact length, wherein the inner cylinder is coupled to a rear wall.

[0016] Figure 5 A cross-sectional top view of a fourth example of a seal is shown, which includes an inner cylinder with a long contact length, wherein there is no additional seal extending beyond the inner cylinder, and wherein the inner cylinder is coupled to the rear wall.

[0017] Figure 6 A cross-sectional top view of a fifth example of a seal is shown, which includes an inner cylinder with a long contact length, wherein there is no additional seal beyond the inner cylinder, but there is a full-length outer cylinder, and wherein the inner cylinder is coupled to the front wall. Detailed Implementation

[0018] The implementation provides a seal for the lead hole of an implantable medical device. The implementation provides a sealed contact length greater than 0.010” for the lead body while maintaining an average contact pressure not greater than (10 psi) / (contact length). Some implementations may further allow the lead to be radially offset from the lead hole for center alignment while maintaining a sealed engagement with the lead body of the lead.

[0019] Figure 1 An implantable medical system 100 is illustrated, comprising an implantable medical device 102 and an implantable medical lead 104. The implantable medical device 102 includes a circuit housing 110 and a head 112 mounted to the circuit housing 110, the circuit housing and the head together forming a complete device housing. The circuit housing 110 provides a sealed enclosure for a circuit 114 and an associated battery 116 that powers the circuit. The circuit 114 may include a stimulation engine capable of generating stimulation pulses. The circuit 114 may also include, or alternatively include, sensing circuitry capable of receiving physiological signals. Examples of the implantable medical device 102 include, but are not limited to, neurostimulators, such as those for sensing and / or stimulating deep brain, spinal cord, pelvis, or peripheral nerves. Such devices can be used to deliver electrical stimulation therapy (and in some cases, therapeutic agents) to various tissue sites in a patient to treat a variety of symptoms or conditions, such as chronic pain, tremor, Parkinson's disease, other movement disorders, epilepsy, urinary or fecal incontinence, sexual dysfunction, obesity, or gastroparesis. In other examples, such devices may be cardiac devices for delivering electrical stimulation to the heart.

[0020] In order to transmit electrical signals, circuit 114 has an electrical connection 118 that establishes an electrical path with conductor 120 present in head 112. Electrical connection 118 may include a feedthrough that allows the electrical path to transition between the interior of circuit housing 110 and the interior of head 112 while maintaining a sealed relationship between circuit housing 110 and head 112.

[0021] The head 112 provides a lead hole 124 including a set of electrical connectors 122. Conductors 120 are electrically connected to the corresponding electrical connectors 122 to deliver electrical signals. The lead hole 124 also includes a set of seals 123 interleaved with the electrical connectors 122. A front seal 126 also provides an outer surface for the head 112 in the area at the opening of the lead hole 124. In this specific example, a second lead hole is present, also including an electrical connector with interleaved seals. Although conductors 120, electrical connectors 122, and seals 123 are... Figure 1 As can be seen, they are sealed together with the head 112 by a layer of liquid silicone rubber or other similar material in a sealed arrangement.

[0022] The proximal end of an implantable medical lead 104 is shown. At this proximal end, the lead includes proximal contacts 106 mounted to a lead body 108. These proximal contacts are conductors, such as metal rings. Conductors within the lead body 108 electrically connect the proximal contacts 106 to a distal electrode located at the distal end of the lead 104.

[0023] The proximal end of lead 104 is inserted into lead hole 124 of implantable medical device 102. Each proximal contact 106 is electrically coupled to a corresponding electrical connector 122. Each seal 123 engages lead body 108 between adjacent contacts 106. A front seal 126 engages the distal lead body 108 of the most distal proximal contact 106. In this example, the front seal 126 includes an opening 128 because it provides an outer surface of head 112 at lead hole 124. This example of lead 104 also includes a surface coating 109, such as a siloxane or parylene coating, to reduce friction as lead body 108 passes through front seal 126. This surface coating 109 may be effective for certain configurations of front seal 126 that might otherwise produce undesirable insertion friction.

[0024] Although Figure 1 This discussion pertains to the front seal 126, but it should be understood that the following description can be used at other sealing locations within the head 112. Figures 2 to 6 The discussion follows a similar structure. Furthermore, it should be understood that, although... Figures 2 to 6 A sealing orientation is shown, but the sealing orientation can be reversed, with the front side becoming the rear side, and vice versa. It should also be understood that although the example shows a single inner cylinder, multiple inner cylinders can be used, such as one inner cylinder located at the front of the front seal 126 and another inner cylinder located at the rear of the front seal 126. The following also relates to... Figures 2 to 6 Let's discuss other variations.

[0025] Figure 2 An example of seal 202 is shown, which can be Figure 1 The front seal 126, or a seal located at a different position within the head 112, includes an inner cylinder 206 having a transition portion 210 at the front wall 212. The seal 202 defines an orifice opening 204 and has a gap 208 between the inner cylinder 206 and an outer cylinder formed by the sealing body. In this example, the inner cylinder 206 lacks any internal protrusions that would result in more complete contact with the lead body along the length of the inner cylinder 206. For some embodiments of the seal 202, to facilitate entry and exit of the lead body through the cylinder 206, the inner surface of the cylinder 206 may include a surface coating 214 to provide lower friction. Examples of such surface coatings include siloxanes and parylene. As described above relative to... Figure 1 Instead of or in addition to surface coating 214, lead body 108 may include surface coating 109 to reduce friction. This example also includes additional seals 218, 220 and defines a rear opening 222.

[0026] The cylinder 206 of seal 202 is configured as a "long contact seal" with reduced average contact pressure, while having a longer contact length than conventional seals. Conventional seals typically have a contact length of about 0.005 inches, where the contact length is the length of the portion of the seal that contacts the structure received by the seal, substantially along its longitudinal axis. In contrast, exemplary seals according to embodiments of this disclosure may have a contact length of at least 0.010 inches, at least 0.025 inches, or at least 0.050 inches (in... Figure 2 The contact length is shown as 223.

[0027] Long-contact seals can be configured to have an average contact pressure within an acceptable range to accommodate reasonable insertion forces when a structure is inserted into the seal (e.g., when a lead body is inserted into seal 202). In one example, such a seal can be configured to have an average contact pressure no greater than K / contact length, where “K” is 10 psi. Accordingly, a seal with a contact length of at least 0.010 inches will exhibit an average contact pressure no greater than 1000 psi, while a seal with a contact length of at least 0.025 inches will exhibit an average contact pressure no greater than 400 psi, and so on. Contact pressure is the pressure exerted by the seal on a structure located within the seal and in contact with an internal portion of the seal (e.g., with cylinder 206 of seal 202) in a substantially vertical direction. Such structures within the cylinder may include the body and / or connector of a therapeutic delivery element, such as a lead, lead extension, catheter, or other element for delivering therapy to a patient. Average contact pressure is the integral of the contact pressure over the contact area between the seal and the structure located within the seal, divided by that contact area.

[0028] According to one embodiment of this disclosure, the seal may be formed of a material with a tensile modulus of elasticity at 5% engineered strain between 100 psi and 1000 psi, or between 400 psi and 2500 psi, or between 1500 psi and 2100 psi, to reduce contact pressure occurring between the inner cylinder 206 and a structure located within and in contact with the inner cylinder. In one example, the cylinder 206 may be formed of silicone rubber with a hardness of 20A to 90A. Alternatively, the cylinder 206 may be formed of polyurethane, such as 80A polyurethane. The cylinder may have a wall thickness of 224 when the cylinder 206 is not under strain of 0.008 inch to 0.030 inch. The head may also be formed of the same material as the cylinder 206.

[0029] Seals with a length of at least 0.010 inches, at least 0.025 inches, or at least 0.050 inches and exhibiting an average contact pressure of no more than (10 psi) / (contact length) may have an insertion force requirement ranging from 0.05 psi / seal to 0.5 psi / seal or between 0.03 psi / seal and 0.3 psi / seal.

[0030] Long contact seals with a contact length of 0.010 inches or greater and an average contact pressure determined as K divided by the contact length (where K is 10 psi) provide sufficient electrical isolation even when there are debris such as elongated polymer molded filaments between the seal 202 and structures such as the lead body inside the cylinder into which the seal is inserted. Figure 2A In such Figure 2 An enlarged cross-sectional view of the cylinder 206 of the seal 202, taken at its midpoint, is shown. The debris filament 230 is shown as being trapped between the cylinder 206 and a structure 232 (e.g., a lead body or extension body) inserted into and in contact with the inner surface of the cylinder 206. In some cases, this filament may extend along the length 223 of the seal 202. Figure 2 This creates a fluid leakage path.

[0031] Figure 2B yes Figure 2AAn enlarged view of portion 240 (shown by dashed lines). For an exemplary debris filament with a diameter of 242 of 0.001” and trapped between the cylinder 206 of the seal 202 and a structure 232 (e.g., a lead body) within the cylinder 206 of the seal, a gap 245 is created on each side of the filament. This gap may be generally triangular in shape, having a height 246 of approximately 0.001 inches and a width 248 of approximately 0.002 inches. The cross-sectional area of ​​each such gap is approximately 1 x 10⁻⁶ square inches. Assuming the debris filament extends the length 223 of the cylinder 206 of the seal 202, and if the resistivity of the body fluid is approximately 30 Ω-inch, the resistivity of the fluid passage formed by each gap along the length of the seal is (30 Ω-inch) x (seal contact length) / (0.000001 inch). 2 For a typical lip seal with a contact length of 0.005 inches, the resistivity of the fluid passage will be approximately 150 kΩ. However, for contact lengths of 0.010 inches or greater, a resistivity of at least 300 kΩ can be achieved. For contact lengths of 0.025 inches or greater or 0.050 inches or greater, resistivities of at least 750 kΩ and at least 1.5 megΩ can be achieved for each leakage passage, respectively. In this example where there are electrical leakage passages on each side of the debris filament, the total resistivity is 75 kΩ for a typical lip seal, but 150 kΩ for a long contact seal with a length of at least 0.010 inches, and at least 375 kΩ and at least 750 kΩ for contact seals with lengths of at least 0.025 inches and at least 0.050 inches, respectively. Therefore, long contact seals can provide sufficient electrical isolation even in environments where fluid ingress is permitted.

[0032] In this example, wall portion 212 defines a transition portion 210 between the end of the inner cylinder 206 and the end of the outer cylinder surrounding the inner cylinder 206. Because the rear end of the inner cylinder 206 is unattached, the transition portion 210 can serve as a hinge-like connection between the inner cylinder 206 and wall portion 212. Since the seal 202 is an elastomer, the transition portion 210 allows the rear end of the inner cylinder 206 to have a degree of freedom of movement within the gap 208, which allows the inner cylinder 206 to maintain a sealed engagement with the lead body 108 even when the lead body 108 can move freely. The following... Figures 3 to 6 The transition section of the additional examples discussed in the text can also provide this hinge-like connection, which provides the internal cylinders of those examples with a degree of freedom of movement to maintain a sealed engagement with the lead body 108.

[0033] For reference Figure 2 The long-contact seals described herein can also be incorporated into other sealing configurations, including... Figures 3 to 6Those shown. Figure 3 An example of a seal 302 is shown, which includes an inner cylinder 306 having a transition portion 310 at the front wall 312. The seal 302 defines an orifice opening 304 and has a gap 308 between the inner cylinder 306 and a head structure surrounding the seal body. In this example, the inner cylinder 306 lacks an inner protrusion that would result in more complete contact with the lead body along the length of the inner cylinder 306. In some embodiments of the seal 302, to facilitate entry and exit of the lead body through the cylinder 306, the inner surface of the cylinder 306 may include a surface similar to... Figure 2 Surface coating 214 and surface coating 314 are used to provide lower friction. As described above, relative to... Figure 1 and Figure 2 Instead of or in addition to surface coating 314, lead body 108 may include surface coating 109 to reduce friction. This example lacks any additional seals, and the inner cylinder 306 defines a rear opening 318 for the seal.

[0034] When the structure is inserted into the cylinder 306, the cylinder 306, having a seal 302 with a contact length 323 and a width 324, can also be configured as a long contact seal. The contact length of the cylinder 306 can be at least 0.010 inches, at least 0.025 inches, or at least 0.050 inches, and the average contact pressure is (10 psi) / contact length. The cylinder can be formed of a material having a tensile modulus of elasticity of 100 psi to 1000 psi, 400 psi to 2500 psi, or 1500 psi to 2100 psi at 5% engineered strain. This long contact seal can be combined with one or more of the other features described herein to allow the seal 302 to provide improved electrical isolation while also enhancing the ability of structures (e.g., leads or lead extensions) inserted into the cylinder 306 to move laterally.

[0035] The seals disclosed herein, including long-contact seals with an average contact pressure of 200 psi or less, can be used in various locations within the head. Such seals can be used as pre-seals to provide electrical isolation from electrical connectors and adjacent body tissues and fluids. Such seals can also be used between electrical connectors within the lead hole of the head to provide electrical isolation between connectors without unduly increasing lead insertion force. While lateral movement of the lead body, which reduces the effectiveness of conventional pre-seals, may be a minor issue, debris between the lead body and the seal remains a problem as it extends deeper into the lead hole of the head. Therefore, this length of contact between the cylinder 306 of seal 302 and the lead body provides sealing benefits for these additional sealing locations.

[0036] same, Figure 4An example of a seal 402 is shown, comprising an inner cylinder 406 having a transition portion 410 at its rear wall. A front wall 412 of the seal 402 defines an aperture opening 404. A gap 408 is formed between the inner cylinder 406 and an outer cylinder formed by a sealing body. In this example, the inner cylinder 406 lacks an inner protrusion that would result in more complete contact with the lead body along the length of the inner cylinder 406. In this example, to facilitate the entry and exit of the lead body through the cylinder 406, the inner surface of the cylinder 406 may include features similar to... Figure 2 Surface coating 214 and surface coating 414 are used to provide lower friction. As described above, relative to... Figure 1 and Figure 2 Instead of or in addition to surface coating 414, lead body 108 may include surface coating 109 to reduce friction. This example also includes additional seals 418, 420, and the inner cylinder 406 defines a rear opening 422 for the seal. When the structure is inserted into cylinder 406, cylinder 406, having a seal 402 with a contact length 423 and a width 424, may also be configured as a long-contact seal. The contact length of cylinder 406 may be at least 0.010 inches, at least 0.025 inches, or at least 0.050 inches, and the average contact pressure is (10 psi) / contact length. The cylinder may be formed of a material having a tensile modulus of elasticity of 100 psi to 1000 psi, 400 psi to 2500 psi, or 1500 psi to 2100 psi at 5% engineered strain. This long-contact seal can be combined with one or more of the other features described herein to allow seal 402 to provide improved electrical isolation while also enhancing the ability of structures (e.g., leads or lead extensions) inserted into cylinder 406 to move laterally.

[0037] Figure 5 An example of a seal 502 is shown, comprising an inner cylinder 506 having a transition portion 510 at its rear wall. The front end 512 of the inner cylinder 506 defines an aperture opening 504. The seal 502 has a gap 508 between the inner cylinder 506 and a head structure surrounding the seal body. In this example, the inner cylinder 506 lacks an inner protrusion that would result in more complete contact with the lead body along the length of the inner cylinder 506. In some embodiments of the seal 502, to facilitate entry and exit of the lead body through the cylinder 506, the inner surface of the cylinder 506 may include a surface similar to... Figure 2 Surface coating 214 and surface coating 514 are used to provide lower friction. As described above, relative to... Figure 1 and Figure 2Instead of or in addition to surface coating 514, lead body 108 may include surface coating 109 to reduce friction. This example lacks any additional seals, and the rear wall of seal 502 defines a rear opening 518 of the seal.

[0038] When the structure is inserted into the cylinder 406, the cylinder 506, having a seal 502 with a contact length 523 and a width 524, can also be configured as a long contact seal. The contact length of the cylinder 506 can be at least 0.010 inches, at least 0.025 inches, or at least 0.050 inches, and the average contact pressure is (10 psi) / contact length. The cylinder can be formed of a material having a tensile modulus of elasticity of 100 psi to 1000 psi, 400 psi to 2500 psi, or 1500 psi to 2100 psi at 5% engineered strain. This long contact seal can be combined with one or more of the other features described herein to allow the seal 502 to provide improved electrical isolation while also enhancing the ability of structures (e.g., leads or lead extensions) inserted into the cylinder 506 to move laterally.

[0039] Figure 6 An example of a seal 602 is shown, comprising an inner cylinder 606 extending the full length of the seal 602, wherein an outer cylinder surrounds the inner cylinder 606 over the full length of the seal 602. The inner cylinder 606 has a transition portion 610 at a front wall 612. The seal 602 defines an orifice opening 604 and has a gap 608 between the inner cylinder 606 and the outer cylinder surrounding the seal body. In this example, the inner cylinder 606 lacks an inner protrusion that would result in more complete contact with the lead body along the length of the inner cylinder 606. To facilitate entry and exit of the lead body through the cylinder 606, the inner surface of the cylinder 606 may include a surface similar to... Figure 2 Surface coating 214 and surface coating 614 are used to provide lower friction. As described above, relative to... Figure 1 and Figure 2 Instead of or in addition to surface coating 614, lead body 108 may include surface coating 109 to reduce friction. This example lacks any additional seals, and inner cylinder 606 defines a rear opening 618 for the seal, although it exists within the entire length of outer cylinder.

[0040] Similar to the seals 202, 302, 402 and 502 mentioned above, Figure 6The seal 602 can be sized to be a long contact seal with an average contact pressure not exceeding (10 psi) per contact length. Such seals can have a contact length of at least 0.010 inch, at least 0.025 inch, or at least 0.05 inch. As an alternative to or in addition to the surface coating 614, such seals generate reduced contact pressure on the lead body. Such seals 602 can also be used to maintain sufficient electrical isolation, even in the presence of debris filaments at various locations between the electrical connector, including the front sealing position and the lead hole deeper into the head. Such seals can be formed from materials having a tensile modulus of elasticity of 100 psi to 1000 psi, 400 psi to 2500 psi, or 1500 psi to 2100 psi at 5% engineered strain. In some examples, such seals are formed from silicone rubber with a hardness of 20A to 90A or polyurethane such as polyurethane 80A.

[0041] It should be understood that Figures 2 to 6 The example provided illustrates a sealing configuration utilizing a long-contact seal. It should be understood that long-contact seals can be incorporated into many other sealing configurations not shown herein, including at any sealing location where the contact length can be increased to 0.010 inches or more substantially along the longitudinal axis of the seal (e.g., the axis of the seal would be generally parallel to the longitudinal axis of the structure inserted into the seal). In some cases, the determination of whether an increase in length can be accommodated can be based on the spacing of the electrical contacts on the structure to be received by the seal.

[0042] The above text is in Figures 1 to 6 The embodiments described herein also apply to lead extensions other than the device head. For example, the lead extension may include a distal end forming a housing that provides a lead hole for receiving an electrical connector very similar to that of the device head. The proximal end of the lead can be inserted into the lead hole of the extension in the same manner as the lead is inserted into the lead hole of the device head. Therefore, any discussion of the use of seals in the lead hole of the device head as discussed herein should also be considered applicable to the use of seals in the lead hole of the lead extension. Furthermore, since the proximal end of the lead extension is inserted into the lead hole of the device head, the seal of the device head can thus operate in conjunction with the lead body of the lead extension to form a seal in the same manner as the lead has been inserted into the lead hole of the device head.

[0043] Although embodiments have been specifically shown and described, those skilled in the art will understand that various other changes in form and detail may be made without departing from the spirit and scope of the invention.

Claims

1. An implantable medical system, the implantable medical system comprising: A therapeutic delivery element having a proximal contact, a body, and a length; A housing defining a first aperture, within which the therapeutic delivery element is located; A circuit located within the housing for delivering treatment to a patient or sensing at least one of the patient's biosignals; An electrical connector, wherein the electrical connector is located within the first hole and is electrically connected to the circuit, wherein the proximal contact is in contact with the electrical connector; and An integral resilient sealing body is coupled to the housing and has a wall that provides an outer surface for part of the housing. The integral resilient sealing body includes a first cylinder defining a sealing orifice, the first cylinder being located within the first orifice and contacting the length of the therapeutic delivery element over a contact length of at least 0.010 inches, and the average contact pressure being no greater than (10 psi) / (contact length).

2. The implantable medical system of claim 1, wherein the contact length is at least 0.025 inches.

3. The implantable medical system of claim 1, wherein the contact length is at least 0.050 inches.

4. The implantable medical system of claim 1, wherein the first cylinder is formed of a material having a tensile modulus of elasticity of 100 psi to 1000 psi at 5% engineered strain.

5. The implantable medical system according to claim 1, wherein the integrated elastic sealing body is formed of silicone rubber with a hardness of 20A to 90A.

6. The implantable medical system of claim 1, wherein the first cylinder has a cylindrical wall with a thickness of 0.008 inches to 0.030 inches.

7. The implantable medical system of claim 1, wherein at least a portion of the integral resilient sealing body is formed to define a gap between at least a portion of the first cylinder and the first hole.

8. A method for electrical isolation of electrical contacts providing a therapeutic delivery element within a surrounding structure having a first hole including an electrical connector, the method comprising: An integral resilient sealing body is provided located within the first orifice and coupled to the surrounding structure. The integral resilient sealing body has a wall that provides an outer surface that is part of the surrounding structure and includes a first cylinder defining a sealing orifice that is configured to receive a portion of the treatment delivery element and establish an electrical contact between the treatment delivery element and the electrical connector of the first orifice. as well as When the portion of the treatment delivery element is received by the first cylinder, contact is made between the first cylinder and the portion of the treatment delivery element over a contact length of at least 0.010 inches, wherein the average contact pressure is not greater than (10 psi) / (contact length).

9. The method of claim 8, wherein the surrounding structure is the distal end of the lead extension.

10. The method of claim 8, wherein the surrounding structure is the device head of the medical device.

11. The method of claim 8, wherein the contact length is at least 0.025 inches.

12. The method of claim 8, wherein the contact length is at least 0.050 inches.

13. The method of claim 8, wherein the first cylinder is formed of a material having a tensile modulus of elasticity of 100 psi to 1000 psi at 5% engineered strain.

14. The method of claim 8, wherein the integral resilient sealing body is formed of silicone rubber with a hardness of 20A to 90A.

15. The method of claim 8, wherein at least a portion of the integral resilient sealing body is formed to define a gap between the first cylinder and at least a portion of the first hole.

16. An implantable medical system, the implantable medical system comprising: The lead wire has a proximal contact and a lead wire body; A lead extension includes a distal end structure defining a lead hole, the lead hole including an electrical connector and at least one integral resilient sealing body having a wall providing an outer surface of a portion of the lead extension, the integral resilient sealing body including a first cylinder, wherein the lead is present within the lead hole such that the proximal contact contacts the electrical connector, and wherein the first cylinder contacts the lead body over a contact length of at least 0.010 inches and the average contact pressure is not greater than (10 psi) / (contact length).

17. The implantable medical system of claim 16, wherein the contact length is at least 0.025 inches.

18. The implantable medical system of claim 16, wherein the contact length is at least 0.050 inches.

19. The implantable medical system of claim 16, wherein the first cylinder is formed of a material having a tensile modulus of elasticity of 100 psi to 1000 psi at 5% engineered strain.

20. The implantable medical system of claim 16, wherein the first cylinder is formed of a material having a tensile modulus of elasticity of 400 psi to 2500 psi at 5% engineered strain.

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