CN111840786A - Implantable medical device and associated connector enclosure assembly - Google Patents

Abstract

An implantable medical device having a connector enclosure is disclosed. A connector enclosure assembly for a medical device may provide a wire channel. The wire passage includes electrical connectors and a seal therebetween within the connector enclosure assembly. Various other aspects may be included in combination with the wire passage, including an angled housing of the connector enclosure assembly, a feedthrough pin extending to the electrical connector, wherein the feedthrough pin may include an angled section, and a set screw passage angled relative to the wire passage to provide fixation of the wire within the wire passage. In one example, the connector enclosure includes a fill port that opens to an elongated chamber within the connector enclosure.

Description

Implantable medical device and associated connector enclosure assembly

Technical Field

The present disclosure relates to implantable medical devices and systems, such as implantable medical devices for providing stimulation therapy to a patient. More particularly, the present disclosure relates to a connector enclosure assembly and corresponding system having a connector surgical tool that can be used with an implantable medical device, and methods of manufacturing such assemblies, devices, and systems.

Background

Implantable Medical Devices (IMDs) typically include a connector enclosure assembly mounted on a sealed enclosure. The connector enclosure assembly receives the proximal end of the medical lead and provides an electrical connection between circuitry of the medical device within the enclosure and a conductor of the medical lead. The connector enclosure assembly may provide a way to secure the medical lead in place while also providing isolation of the electrical connection from the external environment, such as bodily fluids.

Medical devices are expected to become smaller and less obtrusive. This is particularly true for implantable medical devices, where small devices allow for the formation of smaller subcutaneous pockets within the patient. However, the smaller size presents design challenges, particularly with respect to connector enclosure assemblies, where a specific number of electrical contacts may be present. Furthermore, medical leads are typically implanted such that there is an excess of lead near the medical device, and orienting the excess lead as it exits the medical device while maintaining a relatively small subcutaneous pocket is an additional challenge.

Sacral Neuromodulation (SNM) by IMDs is a method of treating bladder and bowel control symptoms by modulating nerves that contribute to control of the pelvic floor and lower urinary tract. The mechanism of action of SNM is the generation of an electric field that modulates sacral nerve function. The sacral nerve affects the behavior of the pelvic floor, lower urinary tract, urinary and anal sphincters, and colon. Unlike oral drugs that target the muscle component of bladder control, SNM provides control of symptoms by directly modulating neural activity.

IMDs for SNM are designed to achieve therapy by generating an electric field via the following system components: programmable neurostimulators and leads. A hermetically sealed battery powers the neurostimulator. The system operates by conducting electrical pulses generated by a neurostimulator through a lead system to generate an electric field around a lead electrode. The field may be electrically defined as having a frequency, a pulse width, and an amplitude; these parameters are programmable. The same field can be generated with either a current controlled output (amplitude measured in microamps) or a voltage controlled output (amplitude measured in millivolts); the field and its effect on the nerve is the same whether the field amplitude is measured in microamps or millivolts.

A plurality of devices are used to configure and manage parameters that define the stimulation produced by the implantable system. The clinician uses the clinician programmer to configure the patient's treatment, and the patient uses the patient programmer to manage their treatment within the range configured by the clinician. The clinician programmer allows the clinician to individually customize the therapy, check for MRI eligibility status, and turn the MRI mode on or off by selecting from a wide range of non-invasive programming parameters and stimulation modes. The clinician programmer interrogates and programs the neurostimulator using telemetry, and displays its current parameters.

The patient programmer allows the patient to turn therapy on and off, to adjust the amplitude within preset clinician-specified limits, to change the therapy configuration (within the clinician-configured therapy configuration), to check for MRI eligibility status, and to turn the MRI mode on or off.

A positive response to the test stimulus from the temporary external neurostimulator is applied to the patient to conform to the IMD. Temporary percutaneous leads (basic evaluation) or long-term leads and percutaneous extensions (advanced evaluation) may be used with external neurostimulators for test stimulation.

Following successful test stimulation, the IMD is placed in a subcutaneous pocket formed by blunt dissection of the subcutaneous tissue in the upper hip region. If the implant is not ready for advanced assessment, a long-term lead is implanted percutaneously near the sacral nerve, and the correct position is confirmed intraoperatively by observing a 1-2 milliamp motor response. The lead is tunneled subcutaneously to connect to the IMD.

Voiding dysfunction is common and may be idiopathic or may have different causes, such as neurological disease or local urogenital factors. Common types of voiding dysfunction include overactive bladder and urinary retention. In many cases, the etiology of voiding dysfunction is well established, such as detrusor hyperreflexia in patients with multiple sclerosis, which leads to urgency and urge incontinence, or urinary retention in patients with benign prostatic hyperplasia, which results from obstruction of the bladder outlet. However, in some cases, the etiology of the micturition problem is unclear and micturition dysfunction is unresponsive to conventional treatment regimens. Once conservative drug therapy and pelvic floor rehabilitation with anticholinergics and/or tricyclic antidepressants has been exhausted, OAB is difficult to control. Similarly, once the blockage has been cleared, there are few options for patients with urinary retention other than clean intermittent catheterization. SNM therapy effected by IMDs provides another treatment for patients with OAB or non-obstructive urinary retention for which conservative treatment has failed and for which irreversible major surgery, such as dilatation cystoplasty or urinary diversion, is contemplated. The rationale for SNM is based on the fact that the nerve roots of S2-S4 provide the main autonomic and somatic innervation of the lower urinary tract (including the pelvic floor, urethra, and bladder).

Bowel control is the result of the synergy of the rectal and anal sphincters. Contributing to the sphincter action are both smooth muscle (internal anal sphincter) and striated muscle components (external anal sphincter and puborectal sling). The activity of striated muscle components is both reflex and spontaneous. In terms of reflexivity, it produces an anal canal closing pressure sufficient to counteract either an intra-abdominal pressure increase or a reduction in the closing pressure of the internal anal sphincter. Spontaneous contraction delays defecation. Insufficiency of both constituents leads to urge and stress urinary incontinence. Determinable muscle damage to the striated sphincter can be surgically treated by repair or supplementation with autologous or artificial materials. A functional defect without a determinable defect is a therapeutic dilemma. Direct electrical stimulation of peripheral nerve sources (i.e., the S2-S4 nerve roots) by established methods in urology for neuromodulation of the striated pelvic floor, urethra, and anal sphincter muscle results in increased function thereof. Thus, SNM therapy achieved by IMDs may also be used to treat fecal incontinence.

SNM generates an electric field near the sacral nerve to modulate neural activity that affects the behavior of the pelvic floor, lower urinary tract, urinary and anal sphincters, and colon. Unlike oral drugs that target the muscle component of bladder control, SNM provides control of symptoms by directly modulating neural activity. The field may be electrically defined as having a frequency (rate), pulse width, and amplitude.

Disclosure of Invention

An implantable medical device having a connector enclosure is disclosed. A connector enclosure assembly for a medical device may provide a wire channel. The wire passage includes electrical connectors and a seal therebetween within the connector enclosure assembly. Various other aspects may be included in combination with the wire passage, including an angled housing of the connector enclosure assembly, a feedthrough pin extending to the electrical connector, wherein the feedthrough pin may include an angled section, and a set screw passage angled relative to the wire passage to provide fixation of the wire within the wire passage. In one example, the connector enclosure includes a fill port that opens to an elongated chamber within the connector enclosure. The fill port may include an opening on a surface of a housing of the connector enclosure. The opening may include a counterbore. In one example, the counterbore is configured to receive a tool to deposit a filler material within the elongated chamber. The present disclosure also discloses a method of depositing a fill material within an elongated chamber.

The devices and systems of the present disclosure will be used for the same clinical conditions and indications, the same intended purposes, use at the same site in the body, and for the same patient population as previous systems and devices used for SMN. The lead has the same anchoring system as the previous tipped lead, the same number of electrodes to provide the same treatment, also made of the same material and spacing. Both the constant current stimulation control of the devices and systems of the present disclosure and the constant voltage control of previous devices and systems allow clinicians to titrate the stimulation dose to the desired effect.

Minor differences between the present system and previous systems (e.g., constant current, rechargeable battery, material, braided lead body, MRI) are not expected to cause the present device to produce significantly different clinical results in terms of relevant key performance (e.g., expected clinical outcome, particular intended purpose, duration of use, etc.). Validation and validation activities to be performed (e.g., bench testing, modeling, system testing, and artifact (availability) testing) are expected to prove that the present system and previous systems are clinically equivalent, and that previous treatment safety and performance is maintained in the present system.

Previous and current system components have similar principles of operation and key performance requirements, are used under the same conditions of use, are used at the same site in the body, and use similar deployment methods. Previous and current system components are similar in design, specification, and nature in many areas, and where they differ, evidence has been listed that will provide evidence that the differences will not affect device security and performance.

The materials used in the present system are selected based on appropriate physical and biological properties, taking into account their intended use and potential interactions with the bodily fluids/tissues with which they come into contact. The materials used in the present system are the same or substantially similar to those in previous systems and have a defined history of use in implantable medical devices.

Drawings

Fig. 1 is a perspective view of an exemplary implantable medical device system according to the principles of the present disclosure;

FIG. 2 is an exploded perspective view of an implantable medical device according to the principles of the present disclosure and that may be used with the system of FIG. 1;

fig. 3 is a perspective view of another example of an implantable medical device system according to the principles of the present disclosure;

fig. 4 is a perspective view of the implantable medical device of fig. 3 with a portion of the canister removed to show internal features;

FIG. 5 is a perspective view of the implantable medical device of FIG. 3 with the connector enclosure removed to further illustrate internal features;

FIG. 6 is a perspective view of an example connector enclosure assembly that may be used with an implantable medical device;

FIG. 7 is another perspective view of the connector enclosure assembly of FIG. 6 that may be used with an implantable medical device; and

fig. 8 is a cross-sectional view of an example of a connector enclosure assembly in which a medical lead resides within a lead channel.

Detailed Description

Aspects of the present disclosure provide implantable medical devices, methods of manufacturing such implantable medical devices, and implantable medical device systems including such implantable medical devices.

Fig. 1 shows an implantable medical device system 20. System 20 includes an Implantable Medical Device (IMD)30 and an implantable medical lead 32. In general, implantable medical device 30 may be of various types, such as devices for generating electrical stimulation and/or for sensing physiological signals for various medical applications such as neurological or cardiac therapy. The implantable medical lead 32 includes a proximal end 40 of a lead body at which a series of electrical contacts 42 are located. Each electrical contact 42 has a respective conductor within the lead body that extends to a distal end (not shown) where a series of electrodes are present. During use, the proximal end 40 is inserted into the implantable medical device, thereby establishing an electrical connection between the electrical contacts 42 of the implantable medical lead 32 and the electrical connector carried by the implantable medical device 30. The stimulation signal generated by the implantable medical device 30 is delivered to the distal end of the implantable medical lead 32 and to the target tissue, and/or the signal sensed at the target tissue by the distal end of the implantable medical lead 32 is delivered to the implantable medical device 30. The system of the present disclosure may optionally include one or more additional components, such as one or more handheld programmers configured and programmed to wirelessly connect with implantable medical device 30.

In some non-limiting embodiments, the system 20 and implantable medical device 30 are configured to be useful or suitable for providing stimulation therapy to a patient (e.g., sacral neuromodulation, among others). Thus, in some embodiments, system 20 can alternatively be described as an implantable programmable neuromodulation system that delivers electrical stimulation to the sacral nerve. The sacral neuromodulation therapy provided by system 20 may be suitable for management of chronically refractory dysfunction of the pelvis and lower urinary tract or bowel, including overactive bladder, fecal incontinence, and non-obstructive urinary retention.

Sacral neuromodulation generates an electric field near the sacral nerve to modulate neural activity that affects the behavior of the pelvic floor, lower urinary tract, urinary and anal sphincters, and colon. The system 20 is configured to generate an electric field using the current-controlled stimulation to modulate the sacral nerve. Electrical stimulation is delivered to biological tissue carrying current in ionic form using a metal electrode provided with an implantable medical lead 32 carrying current in electronic form. The interface between the electrode and the tissue includes a non-linear impedance that is a function of the voltage across the interface. During current-controlled stimulation, the amount of current is adjusted. The voltage is varied according to the actual value of the impedance so that the change in impedance will not affect the total amount of current delivered to the tissue. The current-controlled waveform ensures that the electric field in the tissue is independent of electrode polarization or voltage drop at the electrode-electrolyte interface. Alternatively, in other embodiments, the system of the present disclosure may be configured or programmed to use voltage controlled stimulation.

Fig. 2 illustrates an example of an implantable medical device 30 suitable, for example, for generating sacral neuromodulation therapy stimulation signals. The implantable medical device 30 may be configured to provide a small form factor (e.g., a volume on the order of about 3 cubic centimeters in some non-limiting embodiments) while generating a desired stimulation signal over an extended period of use. In some embodiments, the implantable medical device 30 can be used as a power source for the sacral neuromodulation therapy described above. A smaller form factor or size may allow for a smaller implantation site incision and a smaller subcutaneous pocket, which may result in a more discrete implantation, as compared to conventional stimulation type implantable medical devices. In some embodiments, the implantable medical device 30 includes various features that facilitate small form factor dimensions while providing desirable performance attributes, such as remotely programmable stimulation signals or electrical pulses at therapeutic levels of interest, Magnetic Resonance Imaging (MRI) compatibility, and remote charging.

In some embodiments, the implantable medical device 30 includes or defines a connector enclosure assembly 50, a set screw 52, a primary enclosure assembly or canister 54, circuitry 56, a battery 58, and an optional desiccant assembly 60. Details regarding the various components are provided below. Generally, the circuit 56, battery 58 and desiccant assembly 60 are held within the canister 54. The battery 58 is electrically coupled to the circuitry 56. The connector enclosure assembly 50 is assembled to the can 54 and includes one or more conductor fingers 70 electrically connected to individual circuit components of the circuit 56, particularly contact pads 72. With this configuration, electrical signals generated by the circuitry 56 are transferred to the connector enclosure assembly 50 through the conductor fingers 70. The connector enclosure assembly 50 also forms or defines an access passage 74 that is sized to receive the proximal end 40 of the implantable medical lead 32. Electrical connectors disposed within the connector enclosure assembly 50 engage the electrical contacts 42 and are electrically connected to respective ones of the conductor fingers 70, thereby connecting the circuitry 56 with the implantable medical lead 32. Set screw 52 provides an electrical ground between implantable medical lead 32 and canister 54 when the implantable medical lead is inserted into access channel 72.

The canister 54 may take various forms suitable for holding the circuitry 56 and battery 58 and for assembly with the connector enclosure assembly 50. In some embodiments, canister 54 includes opposing shield bodies 250, 252, an insulating cup 254, and an end cap 256. The shield bodies 250, 252 may be made of a surgically safe, strong material (e.g., titanium, such as titanium alloy 6a1-4VELI alloy according to ASTM F136) and collectively form a sleeve, e.g., the shield bodies 250, 252 may be secured to one another by, for example, laser seam welding applied to the interface edges. The sleeve, in turn, defines an open volume sized and shaped to receive the insulating cup 254. To facilitate the final construction, a pressure sensitive adhesive liner 260 may be provided with the first shield body 250, which liner is removed prior to assembly to the insulating cup 254. The bottom open to the sleeve collectively defined by the shield bodies 250, 252 is closed by an end cap 256. The end cap 256 and connector enclosure assembly 50 may be assembled (e.g., welded) to the shield bodies 250, 252 to provide a hermetically sealed housing.

The insulating cup 254 serves as a frame sized and shaped to fit closely between the shield bodies 250, 252. The insulating cup 254 spatially secures the circuit 56 and the battery 58 by a cavity of appropriate size and shape. The insulating cup 254 may be formed of a non-conductive or insulating material, such as a polymer.

In some non-limiting embodiments, circuitry 56 may include various electrical components and connections suitable for providing a pulse generator for therapeutic stimulation, such as, in some non-limiting embodiments, a constant current stimulation engine, sensing circuitry for measuring physiological parameters, telemetry (e.g., inductive telemetry at 175 KHz) for communicating with external devices, memory, and recharging circuitry. For example, the circuitry 56 may deliver stimulation signals to the contact pads 72 and may process or act on sensing signals received at the contact pads 72. Circuitry 56 optionally provides various stimulation signal parameters, such as current-controlled amplitude with a resolution of 0.1mA steps, an upper limit of 12.5mA, and a lower limit of 0.0 mA; a rate of 3-130 kHz; the pulse width increment is 10 mus, the step size is maximum 450 mus and minimum 20 mus.

The battery 58 may take various forms suitable for generating the desired stimulation signal, and in some embodiments is a rechargeable battery. For example, the battery 58 may incorporate lithium ion (Li +) chemistry, although other battery configurations known in the art are also acceptable.

The desiccant assembly 60 is sized and shaped for installation within the canister 54 and provides or carries a suitable desiccant material to promote a dry environment within the canister 54.

The connector enclosure assembly 50 may be mounted to the tank 54 in a hermetically sealed manner. The conductor fingers 70 and the ground conductors 124 are arranged to extend to corresponding ones of the contact pads 72 and are soldered, such as pressure gas soldered. The desiccant assembly 60 may be placed into the canister 54 after the welding process, or otherwise delayed until the remaining step is the addition of the second shield body 252. In this way, the desiccant is exposed to ambient conditions for only a short period of time before the interior of canister 54 is isolated from the exterior. This may preserve the effectiveness of the desiccant.

Fig. 3 illustrates another example of a medical device system 100 including an IMD 102 and an implantable medical lead 104. The IMD 102 may be of various types, such as devices for generating electrical stimulation and/or sensing physiological signals for various medical applications (e.g., neural or cardiac therapy). The implantable medical lead 104 includes a proximal end 112 of a lead body at which a series of electrical contacts 114 are located. Each electrical contact has a respective conductor within the lead body that extends to a distal end (not shown) where a series of electrodes are present.

The implantable medical lead 104 is implanted into the body with the distal end routed to a desired location so that the electrodes contact the tissue of interest. The proximal end 112 is inserted into the connector enclosure assembly 106 of the IMD 102 via the access port 110. Within the connector enclosure assembly 106, an electrical connector is in contact with each contact 114. Circuitry within the canister 108 provides stimulation signals and/or monitoring for sensing signals by electrically connecting to the connections within the connection enclosure assembly 106. The electrical circuit is thereby also connected to the electrode at the distal end of the implantable medical lead 104 such that a stimulation signal may be provided to the tissue at the electrode and/or a sensing signal may be obtained from the tissue.

In this particular example, the canister 108 relies on separate components to form a hermetically sealed enclosure for the circuitry. That is, the canister 108 includes a bottom cover 116 that may be welded in place or may be integrally formed with the canister 108, and has a base plate 130, shown in fig. 2, which in this example is a component of the connector enclosure assembly 106. During manufacture, the connector enclosure assembly 106 is joined to the tank 108 by bonding (e.g., by welding) the base plate 130 to the top edge of the tank 108. The canister 108, bottom cap 116, and connector assembly 106, as well as including the base plate 130, may be made of a rigid, biocompatible material, such as various grades of titanium.

Fig. 4 illustrates the IMD102 with one side of the can 108 removed to reveal internal components. In this example, IMD102 includes a battery 120 and circuitry 122 housed within an insulative cup 118. The insulating cup 118 may securely hold the components within the can 108 while isolating the components from contact with the can 108. The insulating cup 118 may be constructed of an insulator such as a liquid crystal polymer. In this example, circuit 122 includes electrical contact pads 124. During assembly of the IMD102, the conductors 126 extending from the connector enclosure assembly 106 are aligned with and bonded to the electrical contact pads 124 (e.g., by soldering, spot welding, etc.). As discussed in more detail below, these conductors 126 provide electrical connections between the circuitry 122 and feedthrough pins that provide electrical connections to electrical connectors within the connector enclosure assembly 106.

In this example, since conductors 126 extend from feedthrough pins 136 to contact pads 124, no flex circuit is employed to provide the interconnection. Thus, the structure for interconnecting the flex circuit to the feedthrough pins is omitted.

The conductors 126 pass through a support body 128 secured to the underside of a bottom plate 130. The support body 128 holds the conductors in place for interconnection to feedthrough pins of the connector enclosure assembly 106, and also in place for bonding to the contact pads 124 of the circuitry 122 within the can 108.

Fig. 5 illustrates IMD 102 with the connector enclosure removed to show the set of electrical connectors 132, set screws 134, and feedthrough pins 136. The connector enclosure that has been removed may be constructed of a polymer molded over the component or, in some examples, may be machined from metal. For example, where the connector enclosure is machined from metal, including vias that allow feedthrough pins 136 to avoid contact with the metal enclosure walls, the set of connectors 132 are surrounded by an insulator that separates the connectors 132 from the metal enclosure walls. In addition, the interior of the connector enclosure may be filled with an insulator (e.g., silicone) to further isolate the conductors from the metal enclosure. In this particular example, the feedthrough pins extend up to the connection 132 and make electrical connection with the connection 132. In other examples, an intermediate conductive structure may be present to interconnect feedthrough pin 136 and connector 132.

Fig. 6 and 7 illustrate a connector enclosure assembly 202 that may include features of the connector enclosure assemblies 50, 106 in IMDs 30, 102, respectively. Fig. 6 shows the connector enclosure assembly 202 in a perspective view, in which the protruding portion 220 of the housing 204 can be seen. Set screw 224 is positioned within opening 222 defining a set screw channel. For example, where the housing 204 is constructed of metal, the opening 222 may be machined into the housing 204 having a threaded cylindrical wall such that the set screw 224 is directly threaded into the housing 204. In other embodiments, a separate set screw block having a threaded cylindrical wall to receive set screw 224 may be mounted within housing 204 instead of providing housing 204 with threads. Fig. 7 shows the connector assembly 202 in a perspective view, wherein there is an opening 226 on the protruding portion 220 of the connector enclosure assembly 202 that establishes access to the wire channels. Each of fig. 6 and 7 show the opening 206 leading to the fill port 228.

Fig. 8 illustrates a cross-sectional view of the connector assembly 202 showing the intersecting nature of the set screw channel defined by opening 222 and the wire channel defined by opening 226. In this example, the set screw 224 and set screw channel are at least partially present within the protruding portion 220. The set screw 224 may be tightened against the medical lead 210 to secure the medical lead 210 in place within the lead channel. In this example, the set screw 224 threads directly into the opening 222 formed by the housing 204.

In this example, the set screw 224 functions as a dummy electrical connection in the distal-most position since there are no electrical conductors connecting the set screw 224 back to the circuitry of the medical device. Thus, the set screw 224 may be exposed to the patient's tissue, thus eliminating the use of a backing ring to cover the set screw 224 to shield the set screw from the tissue. In this example, the set screw 224, which is electrically connected to the housing 204, allows the set screw 224 to establish an electrical connection from a connector on the lead body 210 to the housing 204 and/or tissue. This connection to the housing 204 allows the screw 224 to electrically ground an electromagnetic shield that may be present within the lead body 210 for Magnetic Resonance Imaging (MRI) safety purposes.

Housing 204 also defines an elongated cavity 264 that houses electrical connector 240 surrounded by a seal (e.g., distal-most seal 234), and aligns electrical connector 240 with opening 226 to further define the wire passage. In this particular example, the seal including the distal-most seal 234 includes two axially spaced circumferential sealing ridges 236 and 238 to ensure that the electrical connector is adequately sealed from bodily fluids that may migrate into the guidewire channel. Having two circumferential sealing ridges 236, 238 helps seal the wires in the event that there may be some degree of misalignment of the wire body connectors with the connector enclosure assembly 202 connectors.

In this example, the elongated cavity 264 of the housing 204 includes a distal abutment 232 that separates the region where the set screw 224 is located relative to the region where the electrical connector 240 is located. One or more of electrical connections 240 are actively driven by the circuitry of the medical device, so sufficient electrical isolation ensures that housing 204 and set screw 224 are not inadvertently activated. In this example, electrical connector 240 (e.g., a connector available under the trade name Bal Seal from Bal Seal engineering of Foothill Ranch, california) is flangeless. This allows intermediate seal 234 to omit the groove for receiving the flange, which ultimately reduces the width of seal 234 and the connector-to-connector spacing, while seal 234 surrounds the outer peripheral surface of electrical connector 240.

The distal-most seal 234 of this example includes a flap 230 on the distal side that abuts an abutment 232. The elongated cavity 264 of the housing 204 may be filled with a non-conductive filler material, such as Liquid Silicone Rubber (LSR), via the fill port 228, and the filler material engages the flapper 230 to force the flapper to seal against the abutment 232. The shell 204 also includes a fill port 228 in communication with the elongated cavity 264 that allows excess fill material to escape from the elongated cavity 264 within the shell 204. When the baffle 230 is forced against the abutment 232, excess filler material may escape the housing 204 via the fill port 228. In one example, the filler material may be introduced into the elongated cavity 264 from a tool inserted into the opening 206 of the fill port 228.

The fill port 228 may have, for example, a uniform diameter or may have a varying diameter, such as a counterbore 229 at the opening 206 of the housing 204. For example, the fill port 228 may have a length that extends from the opening 206 on the surface of the housing 204 to the elongated cavity 264. In one example, the diameter of the fill port 228 along the length may be uniform or, as shown, vary. For example, the fill port may include a first diameter over a length adjacent the elongated cavity 264 and a second diameter over a length adjacent the opening 206 or the counterbore 229. In one example, the second diameter may be greater than the first diameter. In one example, the first and second diameters may be coaxial, or the axis of the counterbore 229 may be offset from the axis of the diameters over a length proximate the elongated cavity 264. This example shows a counterbore 229 having a cylindrical depth along the axis of the cylinder, but other shapes of counterbore 229 are also contemplated. For example, the counterbore may be funnel shaped or have a cylindrical wall and a funnel shaped base.

In one example, the diameter of the opening 206 and the counterbore 229 are sized to engage a filling tool that may be used to deposit a filling material into the elongated cavity 264. For example, during manufacture, the shell 204 is presented to a filling tool to fill the elongated cavity 264 with a filling material. The filling tool may include a tip that includes an outer diameter that is less than the diameter of the opening 206. The counterbore 228 may be configured to be shaped to mate with the tip of a filling tool and the axis of the fill port 228 along the length adjacent the elongated cavity 264 may be configured to mate with an opening on the tip of the filling tool to deposit the filling material directly into the fill port 228. The tip of the filling tool is inserted into a counterbore 229, which includes a depth configured to receive the tip of the filling tool. The opening on the tip of the filling tool may be aligned with the axis of the filling port 228 on the length adjacent the elongated cavity 264. Once inserted, the filling tool deposits the filling material under pressure into the housing 204, the filling material entering the filling port 228 and then the elongated cavity 264. Once the elongated cavity 264 has received a sufficient amount of the fill material, the fill tool stops depositing. The filling tool is removed from counterbore 229. Excess fill material may escape via fill port 228 and be removed. The counterbore 229 provides a suitable interface for a filling tool that may preferably align the filling tool over a consistent diameter filling port 228 during manufacturing.

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

Claims (4)

1. An implantable medical device and system substantially as shown and described herein.

2. An implantable medical device having a fill port in a housing, the fill port having a counter bore, substantially as shown and described herein.

3. A method of depositing a filler material into a connector enclosure assembly substantially as shown and described herein.

4. A method of depositing a filler material into a connector enclosure assembly having a fill port with a counterbore configured to receive a tip using a fill tool having the tip substantially as shown and described herein.

Images