Releasing a material within a medical device via an optical feedthrough

In general, the disclosure is directed toward releasing material within a medical device via an optical feedthrough. A system for releasing material with a medical device comprises a cup that holds a material, wherein the cup includes a discharge port, a seal disc that seals the material within the cup, an optical feedthrough assembly coupled to the cup, a shell that defines a chamber within a medical device, wherein the optical feedthrough assembly is coupled to the shell, and a radiant energy source that shines a beam through the optical feedthrough assembly to puncture the seal disc to allow the material to enter the chamber via the discharge port.

TECHNICAL FIELD

The invention relates to medical devices.

BACKGROUND

A variety of medical devices are used for chronic, e.g., long-term, delivery of therapy to patients suffering from a variety of conditions, such as chronic pain, tremor, Parkinson's disease, epilepsy, urinary or fecal incontinence, sexual dysfunction, obesity, or gastroparesis. As examples, electrical stimulation generators are used for chronic delivery of electrical stimulation therapies such as cardiac pacing, neurostimulation, muscle stimulation, or the like. Pumps or other therapeutic agent delivery devices may be used for chronic delivery of therapeutic agents, such as drugs. Typically, such devices provide therapy continuously or periodically according to parameters contained within a program. A program may comprise respective values for each of a plurality of parameters, specified by a clinician.

Manufacturing of medical devices and, in particular, medical devices configured for chronic implantation, may be complex. An outer housing of such implantable medical devices (IMDs) may be hermetically sealed to prevent fluid ingress. Additionally, IMDs may be sterilized prior to implantation within a patient. Since failure of an IMD may require surgical explantation of the IMD, IMDs may also be tested to help ensure that they will function as intended throughout their useful life.

SUMMARY

In general, the disclosure is directed toward releasing material within a medical device via an optical feedthrough. Radiant energy may be transferred across an optical feedthrough embedded in a shell of a medical device chamber. Utilizing radiant energy to release a material within a medical device may simplify the manufacturing process by allowing the loading and release of the material to occur at whatever stage of the manufacturing process is advantageous for improving the medical device's flow through the manufacturing operation.

In one embodiment, the invention is directed to a system comprising a cup that holds a material, wherein the cup includes a discharge port, a seal disc that seals the material within the cup, an optical feedthrough assembly coupled to the cup, a shell that defines a chamber within a medical device, wherein the optical feedthrough assembly is coupled to the shell, and a radiant energy source that shines a beam through the optical feedthrough assembly to puncture the seal disc to allow the material to enter the chamber via the discharge port.

In another embodiment, the invention is directed to a method comprising sealing a material within a cup using a seal disc, wherein the cup includes a discharge port, coupling an optical feedthrough assembly to the cup, coupling the optical feedthrough assembly to a shell that defines a chamber within a medical device, and applying radiant energy through the optical feedthrough assembly to puncture the seal disc to allow the material to enter the chamber via the discharge port.

In another embodiment, the invention is directed to a system comprising means for sealing a material within a cup, wherein the cup comprises a discharge port, means for coupling an optical feedthrough assembly to the cup, means for coupling the optical feedthrough assembly to a shell that defines a chamber within a medical device, and means for applying radiant energy through the optical feedthrough assembly to puncture the means for sealing the material within the cup to allow the material to enter the chamber via the discharge port.

DETAILED DESCRIPTION

In general, the disclosure is directed toward performing chemical, metallurgical and biological processes inside the one or more compartments that comprise a medical device. These operations include, but are not limited to, melting, cutting, curing, welding, depyrogenation, and the controlled release and/or mixing of materials within a medical device via an optical feedthrough. Radiant energy may be transferred into or out of a chamber of a medical device across an optical feedthrough embedded in a shell of the medical device chamber. Utilizing radiant energy to release a material within a medical device, to connect previously isolated compartments, cure a substance that has been placed inside the medical device, or to depyrogenate surfaces within the medical device, allows the manufacture and test of each of the individual compartments that will ultimately comprise the medical device to proceed independently, and in parallel, rather than sequentially. This provides a more desirable manufacturing flow, reducing lead-time and enabling measurement of many of the medical device's key quality attributes to be performed on the individual compartments, rather than on the final medical device. Since the measurement of major quality characteristics is performed earlier, on less expensive components, scrap costs are reduced.

FIG. 1is a conceptual diagram illustrating an implantable medical device (IMD) system2including a delivery catheter4coupled to IMD6. In the example illustrated in FIG.1, IMD6is an implantable therapeutic agent delivery device and, therefore, implantable medical device system2may be referred to as implantable therapeutic agent delivery system2. Although the techniques described in this disclosure may be generally applicable to a variety of medical devices including external and implantable medical devices, application of such techniques to IMDs and, more particularly, implantable therapeutic agent delivery devices will be described for purposes of illustration. The disclosure will refer to an implantable therapeutic agent delivery system for purposes of illustration, but without limitation as to other types of medical devices.

The techniques described in this disclosure may be generally applicable to a variety of medical devices including external and implantable medical devices. For example, techniques described in this disclosure may be applicable to a therapeutic agent delivery device configured to deliver a drug or other therapeutic agent to a patient, e.g., via one or more catheters. As another example, techniques described in this disclosure may be applicable to an electrical stimulator configured to deliver electrical stimulation therapy to a patient via one or more stimulation electrodes. Examples medical devices, such as therapy therapeutic agent delivery devices and electrical stimulators, are described in further detail in U.S. Provisional Patent Application No. 61/080,089 to Skelton et al., which was filed on Jul. 11, 2008 is entitled “POSTURE STATE MANAGEMENT FOR POSTURE-RESPONSIVE THERAPY,” and is incorporated herein by reference in its entirety. The techniques described in this disclosure may also be applicable to non-medical devices, such as nanodevices and/or devices with one or more sterile components. Application of the techniques of this disclosure to implantable medical devices (IMDs), e.g., IMD6, will be described for purposes of illustration, but without limitation as to other types of medical or non-medical devices.

As shown inFIG. 1, system2includes an IMD6and external programmer8shown in conjunction with a patient10. In the example ofFIG. 1, IMD6is an implantable therapeutic agent delivery device configured to deliver a therapeutic agent proximate to spinal cord12of patient10, e.g., for relief of chronic pain or other symptoms. Example therapeutic agents include, but are not limited to, pharmaceutical agents, insulin, pain relieving agents, anti-inflammatory agents, gene therapy agents, or the like. A therapeutic agent is delivered from IMD6to spinal cord12of patient10via one or more outlets of catheter4. AlthoughFIG. 1is directed to deliver a therapeutic agent to spinal cord12, system2may alternatively be directed to any other condition that may benefit from the delivery of a therapeutic agent. In addition, patient10is ordinarily a human patient.

IMD6may operate using parameters that define the method of therapeutic agent delivery. IMD6may include programs, or groups of programs, that define different delivery methods for patient10. For example, a program that controls delivery of a drug or other therapeutic agent may include a titration rate or information controlling the timing of bolus deliveries. Patient10may use external programmer8to adjust the programs or groups of programs to regulate the therapy delivery.

In the example ofFIG. 1, catheter4includes one or more infusion outlets that are placed adjacent to the target tissue of spinal cord12. One or more infusion outlets may be disposed at a distal tip of a catheter4and/or at other positions at intermediate points along catheter4. Catheter4may be implanted and coupled to IMD6. Alternatively, catheter4may be implanted and coupled to an external stimulator, e.g., through a percutaneous port. In some cases, an external device may be used on a temporary basis to evaluate potential efficacy to aid in consideration of chronic implantation for a patient.

IMD6may deliver a therapeutic agent to a target tissue via catheter4. In the example illustrated byFIG. 1, the target tissue is spinal cord12. Delivery of a therapeutic agent to spinal cord12may, for example, prevent pain signals from traveling through the spinal cord and to the brain of the patient. Patient10may perceive the interruption of pain signals as a reduction in pain and, therefore, efficacious therapy may result. In other examples, IMD6may deliver a therapeutic agent to other target tissue sites, such as nerves, smooth muscle, and skeletal muscle.

A user, such as a clinician or patient10, may interact with a user interface of external programmer8to program IMD6. Programming of IMD6may refer generally to the generation and transfer of commands, programs, or other information to control the operation of IMD6. For example, external programmer8may transmit programs, parameter adjustments, program selections, group selections, or other information to control the operation of IMD6, e.g., by wireless telemetry. As one example, a user may select programs or program groups. Again, a program that controls delivery of a drug or other therapeutic agent may include a titration rate or information controlling the timing of bolus deliveries. A group may be characterized by multiple programs that are delivered simultaneously or on an interleaved or rotating basis.

In some cases, external programmer8may be characterized as a physician or clinician programmer if it is primarily intended for use by a physician or clinician. In other cases, external programmer8may be characterized as a patient programmer if it is primarily intended for use by a patient. A patient programmer is generally accessible to patient10and, in many cases, may be a portable device that may accompany the patient throughout the patient's daily routine. In general, a physician or clinician programmer may support selection and generation of programs by a clinician for use by IMD6, whereas a patient programmer may support adjustment and selection of such programs by a patient during ordinary use.

IMD6may be constructed with a biocompatible housing, such as titanium or stainless steel, or a polymeric material such as silicone or polyurethane, and surgically implanted at a site in patient10near the pelvis. IMD6may also be implanted in patient10at a location minimally noticeable to patient10. Alternatively, IMD6may be external with one or more percutaneously implanted catheters. For delivery of a therapeutic agent to spinal cord12, IMD6may be located in the lower abdomen, lower back, upper buttocks, or other location to secure IMD6. Catheter4may be tunneled from IMD6through tissue to reach the target tissue adjacent to spinal cord12for therapeutic agent delivery. In addition, IMD6may be refillable to allow chronic therapeutic agent delivery.

Although IMD6is shown as coupled to only one catheter4positioned along spinal cord12, additional catheters may also be coupled to IMD6. Multiple catheters may deliver drugs or other therapeutic agents to the same anatomical location or the same tissue or organ. Alternatively, each catheter may deliver therapy to different tissues within patient10for the purpose of treating multiple symptoms or conditions. In some embodiments, IMD6may be an external device which includes a percutaneous catheter that forms catheter4or that is coupled to catheter4, e.g., via a fluid coupler.

In some examples, IMD6may comprise an electrical stimulator. An electrical stimulator may perform therapy functions similar to a therapeutic agent delivery device via delivery of electrical stimulation therapy instead of therapeutic agent stimulation therapy. In examples in which IMD6is an electrical stimulator, catheter4may include one or more stimulation electrodes (not shown inFIG. 1) and the parameters for a program that controls delivery of stimulation therapy by IMD6may include information identifying which electrodes have been selected for delivery of stimulation according to a stimulation program and the polarities of the selected electrodes.

A program that controls delivery of electrical stimulation by IMD6may also include a voltage or current amplitude. Electrical stimulation delivered by IMD6may take the form of electrical stimulation pulses or continuous stimulation waveforms. In examples in which IMD6delivers stimulation pulses, a stimulation program may also define a pulse width and pulse rate. Electrical stimulation may be used to treat tremor, Parkinson's disease, epilepsy, urinary or fecal incontinence, sexual dysfunction, obesity, or gastroparesis. In this manner, IMD6may be configured to provide therapy taking the form of deep brain stimulation (DBS), pelvic floor stimulation, gastric stimulation, or any other stimulation therapy. In other embodiments, IMD6may be capable of performing both therapeutic agent delivery and electrical stimulation therapy.

FIG. 2is a functional block diagram illustrating various components of an IMD6. In the example ofFIG. 2, IMD6includes a processor20, memory22, therapy module24, telemetry circuit26, and power source28. Memory22may store instructions for execution by processor20, therapy data, and any other information regarding therapy or patient10. Therapy information may be recorded for long-term storage and retrieval by a user, and the therapy information may include any data created by or stored in IMD6. Memory22may include separate memories for storing instructions, program histories, and any other data that may benefit from separate physical memory modules.

Processor20controls therapy module24to deliver therapeutic agent and/or electrical stimulation via catheter4according to therapy instructions stored within memory22. Components described as processors within IMD6, external programmer8or any other device described in this disclosure may each comprise one or more processors, such as one or more microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), programmable logic circuitry, or the like, either alone or in any suitable combination.

Processor20may access locations in memory22to retrieve therapy parameters for a program and control therapy module24to deliver therapy via the indicated program parameters. Therapy module24, e.g., under control of processor20, then makes use of the therapy parameters in delivering the therapeutic agent and/or electrical stimulation to patient10. Processor20also may control telemetry circuit26to send and receive information to and from external programmer8.

In examples in which IMD6is configured to deliver a therapeutic agent to patient10, therapy module24may include a reservoir to hold the therapeutic agent and a pump mechanism to force the therapeutic agent out of catheter4and into patient10. Memory22may contain programs or groups of programs that define the therapeutic agent delivery therapy for patient10, and processor20may control therapy module24according to therapy instructions stored within memory22. A program may indicate the bolus size or flow rate of the therapeutic agent, and processor20may control therapy delivery accordingly.

In examples in which IMD6is configured to deliver electrical stimulation, therapy module24may include stimulation generation circuitry to generate stimulation pulses or waveforms and switching circuitry to switch the stimulation across different electrode combinations, e.g., in response to control by processor20. In particular, processor20may control the switching circuitry on a selective basis to cause therapy module24to deliver electrical stimulation to selected electrode combinations. In other embodiments, therapy module24may include multiple current or voltage sources to drive more than one electrode combination at one time. Memory22may contain programs or groups of programs that define the electrical stimulation therapy for patient10, and processor20may control therapy module24according to therapy instructions stored within memory22. A program may indicate an electrode combination, the polarities of the selected electrodes, and a voltage or current amplitude. When electrical stimulation pulses are delivered, a program may also include a pulse width and pulse rate.

Telemetry module24includes any suitable hardware, firmware, software or any combination thereof for communicating with another device, such as external programmer8. Under the control of processor20, telemetry module24may receive downlink telemetry from and send uplink telemetry to programmer8with the aid of an antenna, which may be internal and/or external. Processor20may provide the data to be uplinked to programmer8and the control signals for the telemetry circuit within telemetry module24, e.g., via an address/data bus. In some examples, telemetry module24may provide received data to processor20via a multiplexer.

Wireless telemetry between IMD6and external programmer8may be accomplished by radio frequency (RF) communication or proximal inductive interaction of IMD6with external programmer8. Telemetry circuit26may send information to and receive information from external programmer8on a continuous basis, at periodic intervals, at non-periodic intervals, or upon request from IMD6or programmer8. To support RF communication, telemetry circuit26may include appropriate electronic components, such as amplifiers, filters, mixers, encoders, decoders, and the like.

The various components of IMD6are coupled to power source28, which may include a rechargeable or non-rechargeable battery or a supercapacitor. A non-rechargeable battery may be selected to last for several years, while a rechargeable battery may be inductively charged from an external device, e.g., on a daily or weekly basis.

FIG. 3is a conceptual diagram illustrating a cross-sectional view of material release assembly30and chamber32of implantable therapeutic agent delivery device6. In the example illustrated inFIG. 3, material release assembly30is configured to release propellant into chamber32of implantable therapeutic agent delivery device6. Although the techniques described in this disclosure may be generally applicable to a release of any suitable material within a medical device, propellant release is described herein as one example application of releasing a material within a medical device, but without limitation as to other types of materials that may be released.

IMD6includes reservoir34configured to hold a therapeutic agent. Reservoir34is expandable and includes bellows36that aid in allowing reservoir34to expand. Reservoir34is enclosed within chamber32. In the illustrated example, chamber32is configured to hold a propellant. Material release assembly30may release a specific volume of propellant into chamber32. For example, material release assembly30may be filled with a measured amount of propellant for release into chamber32. Once released into chamber32, the propellant, e.g., in the form of gas, exerts pressure on reservoir34. The pressure may aid in driving the therapeutic agent from reservoir34to a pump mechanism of therapy module22(FIG. 3), which dispenses the therapeutic agent based on therapy parameters values of a selected program, e.g., at a rate defined by a selected program. The pressure that the propellant exerts on reservoir34may allow reservoir34to fully compress.

Chamber32may be enclosed within shell38. More specifically, shell38defines chamber32such that once material release assembly30releases the propellant into chamber32, the propellant is confined within the boundaries of shell38. In the example illustrated inFIG. 3, outer housing39of IMD6defines a portion of shell38, and material release assembly30is embedded in the portion of housing39that defines a portion of shell38. As described with further detail with respect toFIGS. 4 and 5, material release assembly30may be partially embedded within shell38such that an outer surface of material release assembly30remains uncovered.

Although material release assembly30is coupled to an outer housing39of IMD6in the example of propellant release illustrated in theFIGS. 3, in other examples material release assembly30may be coupled to other portions of shell38or any other shell that defines a chamber within IMD6. In general, material release assembly30may be coupled to a portion of a shell that defines a chamber within IMD6to facilitate release of a material within the chamber. A shell that defines a chamber does not necessarily include a portion of outer housing39of IMD6. For example, IMD6may include one or more shells that are fully enclosed within housing39, and each of the shells may define a chamber within IMD6.

FIG. 4is a conceptual diagram illustrating a perspective view of various components of material release assembly30. Material release assembly30comprises cup40, seal disc42, and optical feedthrough assembly44. Cup40is configured to hold the material intended from release into chamber32(FIG. 3) defined by shell38. Cup40may take the form of any shape and is not limited to the shape of cup40illustrated inFIG. 4. The material may be inserted into cup40and seal disc42may be coupled to cup40to seal the material within cup40. Cup40may be filled with a measured amount of material to allow material release assembly30to release a specific amount of material into chamber32. In general, the material may be a gas.

Cup40includes discharge port46, which may take the form of a hole in cup40. In order to seal the material within cup40, sealing disc42may couple to cup40such that the material is prohibited from escaping from both discharge port46and the opening47of cup40. For example, seal disc42may be coupled to cup40at a location between the material and discharge port46. The coupling between cup40and seal disc42is described with further detail with respect toFIG. 6.

Optical feedthrough assembly44includes optical window48. Optical window48may be configured to allow radiant energy to pass through. For example, optical window48may be transparent. The shape and material composition of optical window48may be selected based on the desired optical characteristics of optical window48. Optical window48may, for example, be constructed of glass, sapphire, polymer, and/or crystalline material. For example, optical window48may be constructed of single-crystal sapphire or thermal shock resistant borosilicate glass. Optical feedthrough assembly44may also comprise ferrule fitting49. Ferrule fitting49may be sized, shaped, and/or otherwise configured to allow optical feedthrough assembly44to be coupled to cup40.

Optical feedthrough assembly44may be configured to fit within an aperture defined by shell38of cavity32(FIG. 3). A portion of shell38is shown inFIG. 4for purposes of illustration. In the example illustrated inFIG. 4, shell38defines aperture54that may be configured to accept optical feedthrough assembly44.

FIG. 5is a conceptual diagram illustrating a perspective view of material release assembly30coupled to shell38such that optical feedthrough assembly44remains uncovered by shell38. Optical feedthrough assembly44may be welded or otherwise coupled to shell38. As one example, optical feedthrough assembly44may be welded to shell38around the perimeter of aperture54.

In some examples in which outer housing39(FIG. 3) of IMD6forms a portion of the shell38of chamber32(FIG. 3), optical feedthrough assembly44may be coupled to housing39. In such examples, aperture54may comprise an aperture of housing39. In examples in which IMD6is configured for implantation within patient10(FIG. 1), housing39of IMD6may be constructed of biocompatible materials, such as titanium or stainless steel, or a polymeric material such as silicone or polyurethane. Housing39may also be hermetically sealed to prevent fluid ingress. In such examples, the interface between optical feedthrough assembly44and housing39may be hermetically sealed, e.g., using biocompatible materials.

As illustrated inFIGS. 4 and 5, radiant energy source50, e.g., laser50, may shine beam52through optical window48and onto seal disc42. As described in further detail with respect toFIG. 6, beam52may puncture a hole in seal disc42to allow the material to escape from cup40to chamber32(FIG. 3). By coupling material release assembly30to shell38of chamber32, the material may be released into chamber32after chamber32has been fully sealed. Additionally, if material release assembly30is coupled to an outer housing39(FIG. 3) of IMD6, the material may be released into chamber32after the entire IMD6has been fully assembled and sealed. Therefore, material release assembly30may allow a material to be released into chamber32at a later stage in the manufacturing process.

FIG. 6is a conceptual diagram illustrating a cross-sectional view of material release assembly30. Seal disc42may seal the material within cup40. For example, cup40may define a lip60that accepts seal disc42. After seal disc42is placed on lip60of cup40, seal disc42may be welded to cup40. For example, welding may occur around the circumference of seal disc42where seal disc42joins cup40. One or both of cup40and seal disc42may be constructed of titanium and/or other metals to facilitate welding. In this manner, seal disc42may enclose a material, e.g., material61, within cavity62of cup40and prevent the material from escaping from discharge port46. In some examples, cup40may be filled with a measured amount of material to allow material release assembly30to release a specific amount of material into chamber32(FIG. 3).

Cup40may also define a lip64that mates with a lower lip of optical feedthrough assembly44, and once optical feedthrough assembly44is placed on lip64, optical feedthrough assembly44may be welded to cup40. For example, welding may occur around the circumference of optical feedthrough assembly44where optical feedthrough assembly44joins cup40. Although welding is described as an example means for coupling cup40to seal disc42and optical feedthrough assembly44, other systems and techniques for coupling elements together may be utilized. For example, cup40may be coupled to seal disc42and/or optical feedthrough assembly44via an adhesive, such as an epoxy.

Optical feedthough assembly44may also define an upper lip66. Upper lip66may mate with aperture54of shell38. For example, aperture54may be configured to abut against upper lip66of optical feedthrough assembly44. Once optical feedthrough assembly44is placed within aperture54of shell38, optical feedthrough assembly44and shell38may be coupled together.

In examples in which aperture54comprises an aperture of the outer housing39(FIG. 3) of IMD6and IMD6is configured for implantation within patient10, the interface between optical feedthrough assembly44and housing39may be hermetically sealed. As one example, optical feedthrough assembly44may be welded to housing39around the perimeter of aperture54, e.g., where optical feedthrough assembly44joins housing39, to create a hermetic seal.

Once material release assembly30has been assembled and coupled to shell38, beam52may shine through optical window48and onto seal disc42. Beam52may puncture a hole in seal disc42to allow the material within cavity62to escape from cup40via discharge port46. Since discharge port46is enclosed within shell38of chamber32(FIG. 3), the material transfers from cup40to chamber32via discharge port46. By coupling material release assembly30to shell38of chamber32, the material may be released into chamber32after chamber32has been fully sealed. Additionally, if material release assembly30is coupled to an outer housing39(FIG. 3) of IMD6, the material may be released into chamber32after the entire IMD6has been fully assembled and sealed. Therefore, material release assembly30may allow the material to be released into chamber32at a later stage in the manufacturing process.

In some examples, IMD6may include a plurality of material release assemblies30to facilitate release of one or more materials into the same or different chambers within IMD6. For example, IMD6may include two material release assemblies30that release the same or different material into two different chambers. As another example, IMD6may include a plurality of material release assemblies30that release different materials into one chamber. Once released the different materials may mix within the chamber. This may be particularly useful when reducing exposure to the mixed materials is desirable, e.g., when a mixture of the released materials is hazardous. Additionally, each of the plurality of material release assemblies30may be filled with a measured amount of material such that the chamber receives a controlled composition of the material mixture. By controlling the amount of material inserted into each material release assembly30, the mixing ratio may be controlled.

Additionally or alternatively, one optical feedthrough assembly44may allow access to multiple cups40that are individually sealed with respective seal discs42.FIG. 7is a conceptual diagram illustrating a cross-sectional view of material release assembly70that includes two individually sealed cups40A and40B. Cups40A and40B may take the form of any shape and are not limited to the shape of cups40A and40B illustrated inFIG. 7.

Material release assembly comprises cups40A and40B, sealing discs42A and42B, discharge ports46A and46B, and optical feedthrough assembly44. Cups40A and40B may each hold a material, e.g., materials41A and41B respectively, for release into chamber32(FIG. 3). Cups40A and40B may be individually sealed by seal discs42A and42B, respectively. A measured amount of material may be sealed within each of cups40A and40B. Cups40A and40B may hold the same or different material as well as the same or different amounts of material.

Cups40A and40B may be coupled to optical feedthrough assembly44. For example, cup40A may be coupled to optical feedthrough assembly44at outer edge72A and cup40B may be coupled to optical feedthrough assembly44at outer edge72B. In the illustrated example, cups40A and40B are joined at their interface74. In other examples, cups40A and40B may be unjoined. Optical feedthrough assembly44is coupled to shell38, as described with respect toFIG. 6.

Beams52A and52B of radiant energy may shine through optical window48of optical feedthrough assembly44to puncture seal discs42A and42B, respectively. Puncturing seal discs42A and42B allows the materials held in cups40A and40B to enter chamber32(FIG. 3) via discharge ports46A and46B. Two discharge ports46A and46B are illustrated inFIG. 7for purposes of example. In other examples, the materials from cups40A and40B may enter chamber32via the same discharge port.

FIG. 8is a flow diagram illustrating an example technique for releasing a material within IMD6. Although the technique illustrated inFIG. 8is described with respect to the example of material release assembly30illustrated inFIG. 6, techniques for releasing a material within a medical device are applicable to other embodiments of material release assemblies. First, a material is inserted into cup40, which defines discharge port46(80). Cup40may be filled with a measured amount of material to allow material release assembly30to release a specific amount of material into chamber32(FIG. 3). After the material is inserted into cup40, the material is sealed within cup40using seal disc42(82). For example, seal disc42may be inserted into cup40such that seal disc42abuts lip60of cup40. Once inserted, seal disc42may be coupled to cup40to seal the material within cup40. For example, seal disc42may be welded to cup40about the circumference of seal disc42. In general, seal disc42may be positioned between the material and discharge port46to prevent the material from escaping from discharge port46.

After the material is sealed within cup40, optical feedthrough assembly44is coupled to cup40(84). Cup40may include lip64configured to mate with a lower lip of optical feedthrough assembly44to aid in coupling cup40and optical feedthrough assembly44. As one example, optical feedthrough assembly44may be welded to cup40around the circumference of optical feedthrough assembly44where optical feedthrough assembly44joins cup40.

In examples in which aperture54comprises an aperture of the outer housing39(FIG. 3) of IMD6and IMD6is configured for implantation within patient10, the interface between optical feedthrough assembly44and housing39may be hermetically sealed. As one example, optical feedthrough assembly44may be welded to housing39around the perimeter of aperture54, e.g., where optical feedthrough assembly44joins housing39, to create a hermetic seal.

Once material release assembly30has been assembled and coupled to shell38, radiant energy, e.g., in the form of beam52(FIG. 4), is applied through optical feedthrough assembly44to puncture seal disc42(88). Puncturing seal disc42allows the material within cup40to escape via discharge port46. Since discharge port46is enclosed within shell38of chamber32(FIG. 3), the material transfers from cup40to chamber32via discharge port46. By coupling material release assembly30to shell38of chamber32, the material may be released into chamber32after chamber32has been fully sealed. Additionally, if material release assembly30is coupled to an outer housing39(FIG. 3) of IMD6, the material may be released into chamber32after the entire IMD6has been fully assembled and sealed. Therefore, material release assembly30may allow a material to be released into chamber32at a later stage in the manufacturing process.