A multi-lead multi-electrode system and method of manufacturing the multi-lead multi-electrode system includes a multi-electrode lead that may be used to deploy multiple separable electrodes to different spaced apart contact sites, such as nerve or muscle tissues, for example, that are spatially distributed over a large area.

FIELD OF THE DISCLOSURE

The present disclosure relates generally to a multi-lead multi-electrode system having multiple separable electrodes, methods, and components related thereto.

BACKGROUND

In the past decade, there have been significant advances in development of neurotechnology to stimulate neural and muscle tissue to replace lost function due to neurological disability or neutoruma. For example, there are commercially available systems for deep brain stimulation to treat symptoms of Parkinson's disease and other neuromotor and neuropsychological diseases; vagal nerve stimulation for treating some types if intractable epilepsies and depression, gastric stimulation for gastroparesis, stimulation of the peroneal nerve for foot drop, sacral nerve stimulation for urinary urge incontinence and incontinence, pacing of respiratory and abdominal muscles for respiratory insufficiency, and treatment of unmanageable and pathological pain in various sites of the body.

Most often, a single lead is used to target a single stimulation site, for example for vagal nerve stimulation. Here, there is a single electrode contact site connected via the lead to a stimulating device. In some instances a single lead contains multiple electrode contacts in concentric circles along its longitudinal axis placed at a pre-determined distances. Such a lead is used to stimulate close but longitudinally spatially separated excitable neural tissue, for example, for deep brain stimulation for treating Parkinson's disease spinal cord stimulation for pain management and inner ear (cochlear) stimulation for treating hearing loss. Since, in all of the above multi-electrode lead configurations the contacts are placed on an inseparable substrate at a predetermined distance, they cannot be used for stimulating multiple sites that are spatially distributed over a large 2-dimensional area such as for gastric stimulation.

Additionally, for some functional outcomes, multiple nerve or muscle tissues may have to be stimulated in a coordinated manner to achieve the best functional outcome. For example, for restoring respiration in high quadriplegic subjects and in other respiratory disorders, along with phrenic nerve multiple muscles that are spatially distributed need to be stimulated. In gastroparesis and in other gastric disorders, spatially distributed muscles and nerve endings need to be stimulated and/their activity needs to be sensed.

In addition, there have been attempts to provide sensory feedback to upper extremity amputees by stimulation of the peripheral nerves. Such peripheral nerve stimulation will also require multiple nerves to be targeted to provide information about multiple sensory sources and modalities to the amputee. In order to develop the next generation of neural driven prostheses for amputees, it will also be necessary to record multiple motor intents by recording from different sites, for example different peripheral nerves or muscle tissues. Some specific examples are discussed briefly hereinafter.

MedImplant Patent OS-P5330342, from September 1976, shows a system with a coiled lead of multiple connecting elements partially encased and then each individual connecting element is left free. Each individual connecting element is coiled. No protective bundling method is revealed.

U.S. Pat. No. 7,967,817 refers to a multi-electrode lead containing multiple electrode contacts in concentric circles along its longitudinal axis placed at a pre-determined distances.

U.S. Pat. No. 6,505,075 is an example for peripheral nerve stimulation to treat pain using longitudinal circular multi-contact lead.

U.S. Pat. No. 3,699,956 describes a percutaneous lead that provides fixation and minimizes bacterial penetration.

U.S. Patent Application Publication No. 2007/0255369 describes a percutaneous lead with flaps acting as anchors.

U.S. Pat. No. 4,934,368 describes two nerve cuff electrodes as a separate leads.

There is a need for a multi-electrode lead with separable electrode contacts to target nerve or muscle tissues that are spatially distributed over a large area.

SUMMARY

According to some aspects of the present disclosure, a multi-electrode lead and/or a packaging system for such a multi-electrode lead includes any one or more of the components described herein.

According to some aspects of the present disclosure, a multi-lead multi-electrode system includes any one or more of the components described herein.

According to some aspects of the present disclosure, a method of fabricating a multi-electrode lead includes any one or more of the fabrication steps described herein.

Additional optional aspects and forms are disclosed, which may be arranged in any functionally appropriate manner, either alone or in any functionally viable combination, consistent with the teachings of the disclosure. These and other aspects and advantages will become apparent upon consideration of the following detailed description.

DETAILED DESCRIPTION

This disclosure describes a multi-lead multi-electrode system that may be used to deploy multiple separable electrodes (contact sites) to different nerve or muscle tissues, for example, nerve or muscle tissues that are spatially distributed over a large area, and a process for packaging such a system.

A multi-electrode lead is defined as a longitudinal structure that can link a plurality of sensing or stimulating elements (electrodes) at its distal end to a stimulating or recording device or devices at its proximal end using connecting elements. Examples of connecting elements include metal wires that conduct electrical signals, ribbon cables that connect to an array of electrodes, optical fibers that conduct light, and similar devices. Preferably, the multi-electrode lead could be used as a lead across the skin connected to an external connector or device or as an implantable lead that connects to an implantable device.

Turning now to the drawings,FIGS. 1-8illustrate a packaging system for a single multi-electrode lead.FIG. 1illustrates a multi-electrode lead12with electrodes1on one end, or distal end, a stimulating or recording device2on the other end, or proximal end, and elongate connecting elements3, such as wires and/or fiber optic strands, extending between the one end and the other end. The connecting elements3are coated with a thin film of biocompatible material that insulates it from the body fluids. The connecting elements3are secured together in a bundle between the proximal and distal ends. The bundle of connecting elements may be coiled over a partial length to provide strain relief and allow flexibility to the multi-electrode lead. In some instances this coiling may not be present. In some instances, connecting elements3outside the coil sheath4may individually be coiled. The electrodes1and the distal ends of the connecting elements3are separated or readily separable, i.e., not bundled or connected together or easily and readily separable such as along a frangible section or removable temporary connection, such that the electrodes may be placed on or in a patient in a spaced apart array to be operatively engaged with a plurality of spaced apart nerve or muscle tissues that are spatially distributed over a large area, such as to span multiple organs and/or muscle groups and/or nerve regions.

FIG. 2illustrates the coiled portion of the multi-electrode lead12ensheathed, i.e., sheathed within, such as by being surrounded and at least partly encased within a sheath or casing, in a coil sheath4. The coil sheath4is preferably formed of a tube of biocompatible material. The ensheathing element (e.g., the coil sheath4) may extend beyond the coiled portion. The coil sheath keeps the coiled bundle in place.

FIG. 3illustrates individual connecting elements ensheathed separately by individual protective sheaths5. Each protective sheath5is preferably formed of a tube of biocompatible material. This ensheathing of individual connecting elements3permits separation of individual electrode contacts. The length of the connecting elements3may be varied. The individual ensheathing tubes (e.g., the protective sheaths5) extend beyond the electrode so that the terminal ends can be bundled together with an end sheath6as illustrated inFIG. 4. The end sheath6is preferably formed of a tube of biocompatible material. The end sheath6preferably forms a snug fit around all of the individual ensheathed connecting elements3. The end sheath6preferably allows the individual connecting elements3to remain in a single manageable bundle.

FIG. 5illustrates a protective biocompatible tube forming an outer sheath7that overlaps the coil sheath4on one end of the multi-electrode lead12and extends beyond the end sheath6on the other end. This outer sheath7is preferably a slit tube that allows insertion of the multiple ensheathed connecting elements3. The outer sheath7may be closed using different methods. One method is to use circumferential sutures8applied over the end sheath6and the coil sheath4portions of the lead12such that direct compression force is not applied to the individual connecting elements3. Another method, which is illustrated inFIG. 6, is to use a continuous run threaded suture9, which may be aligned longitudinally along the bundle, and which may be easily unraveled during surgery.

FIG. 7illustrates flap like structures, such as flaps10, that are attached to the coil sheath4. These flaps10may be made of biocompatible material, such as silicone, and may be pre-attached to the coil sheath4either during the process of making the coil sheath4tube or with a medical adhesive. The flaps10are pliable and preferably approximately 300 to 500 microns in thickness allowing them to be easily bent. These flaps10can be sutured to fascia or other tissue through or near which the lead12is being tunneled to anchor the lead. For percutaneous leads, the flaps10may be positioned on the portion of the lead adjacent to the inner surface of the skin. On insertion of the lead12, the flaps10may be spread by the inner surface of the skin, as illustrated inFIG. 8, thereby providing a barrier for exteriorizing of the lead12through the skin11. The flaps10also provide a barrier for migration of external infectious agents into the body. The flaps10can be coated with antibacterial, anti-inflammatory agents during the lead insertion process.

As illustrated inFIGS. 9A and 9B, multiple such multi-electrode leads12can be prepared with their proximal ends connected to a single device, such as an external connector13or an implantable pacemaker14.

For deployment, individual multi-electrode leads12are routed to the vicinity of the target site for the electrode contact. The sutures8and/or9securing the outer sheath7are removed and the individual connecting elements3with their protective sheaths5and end sheath6are lifted along the slit portion of the outer sheath7, which is discarded. Each individual connecting element3may be removed from the end sheath6as needed. The individual protective sheath5from the connecting element3is removed and the electrode1, electrode array, or distal end is anchored to and/or inserted into the targeted tissue.

In one embodiment, a multi-lead multi-electrode system including one or more of the multi-electrode leads12may be used for recording peripheral nerve motor activity from multiple nerves at multiple sites using longitudinal intrafascicular electrodes. In such a distributed intrafascicular multi-electrode (DIME) system, there may be multiple leads targeting multiple nerves, where each multi-electrode lead is made up of 6 connecting elements. The connecting element consists of a Pt—Ir (90-10) wire of 25.4 μm diameter coated with biocompatible PTFE material of 7.6 μm thickness. Each Pt—Ir wire may be encased in a protective sheath consisting of a biocompatible polyimide tube of 160 microns inner and 179 micron outer diameter. Six such elements may be encased in an end sheath formed of a biocompatible silicone tube of 508 micron inner diameter and 940 micron outer diameter. The coil sheath formed of a biocompatible silicone tube has inner and outer diameters of 300 and 600 microns, respectively. The outer sheath formed of a biocompatible silicone tube has a 1400 microns inner diameter and 2000 microns outer diameter.

FIG. 10illustrates method steps for a typical process of fabricating the lead12. At30, elements3are prepared for connecting to the lead12. At31, the connecting elements3are coiled and inserted into the coil sheath4. At32, the active electrode contacts1are created. At33, the connecting elements3and the active electrode contacts1outside of the coil sheath4are inserted into the protective sheath5. At34, all of the protective sheaths5are bundled together and inserted into the end sheath6. At35, the entire bundle, from the coil end to the end sheath6, is inserted into the outer sheath7. At36, the outer sheath7is closed, for example, with the suture8and/or9. At37, the proximal end is connected to an operative device14, such as a recording device or a stimulating device, or to a connector that connects to such an operative device.

FIG. 11illustrates one preferred embodiment of a multi-lead multi-electrode management system constructed in accordance with the teachings of this disclosure. In this arrangement, a separate ground electrode25that is not part of the packaged lead12is also illustrated. At least one, and preferably more than one of the multi-electrode leads12are connected to the operative device24. Further, the ground electrode25is operatively connected with one or more of the multi-electrode leads12. However, a multi-lead multi-electrode management system is not limited to the components shown inFIG. 11, and may include additional components or fewer components.

As illustrated inFIG. 12, the outer sheath7ofFIG. 5may be prepared by first making a transverse cut14at the proximal end and subsequently slitting the outer sheath longitudinally along its length15.

As illustrated inFIG. 13, the coil sheath4may have an anchoring structure17at its distal end. The anchoring structure17serves to hold the suture8or9securing the outer sheath7to coil sheath4in place. In the illustrated embodiment, the anchoring structure17has an “arrow head” shape including a raised circumferential “ridge” like structure with a conical tip. The ridge structure is preferably formed by patterning silicone on top of the coil sheath.

FIG. 14illustrates one exemplary arrangement of the flaps10ofFIGS. 7 and 8, the flaps10having the form of a petal anchor19. The petal anchor19can be fabricated using any flexible tube like structure, preferably made out of biocompatible material. In one embodiment, the petal anchor19is fabricated using a silicone tube as illustrated inFIG. 14. One end of the tube is split into 3 or more parts of desired length along its length to form multiple petal like structures18extending from a base portion20. The parts18are preferably equally sized. The petal base20can be reinforced by adding an additional layer of silicone.

FIG. 15illustrates a fully assembled coil sheath4with a “ridge” like structure17at the distal end, and the petal anchor19at the proximal end. During percutaneous implantation, for example into a human patient, the petal like structures18the petal anchor19open up once the coil sheath4is pushed across the skin11, as illustrated inFIG. 16. Once open, the anchor19serves to reduce the in-out movement of the lead into and/or out of the patient, thereby minimizing the chance of infection due to “pistoning” effect. The petal anchor19also provides a barrier for exteriorizing of the lead12through the skin11.

FIG. 17illustrates an individual protective sheath5along with proximal1704and distal1706apertures. As previously illustrated inFIG. 3, individual connecting elements3may each be ensheathed by individual protective sheaths5that may comprise a tube of biocompatible material. Sterilization of connecting elements3is required in order to introduce them in a human body and is achieved by adequate penetration of a sterilization agent into the space between the protective sheath5and connecting elements3. As illustrated inFIG. 17, in order to allow the sterilization agent to reach the connecting elements3, apertures1704,1706are introduced to the protective sheathes5.

Apertures1704,1706may be distributed along the entire length of the protective sheath5or over defined lengths of the protective sheath5. In one embodiment, the protective sheaths5are manufactured of a biocompatible polyimide tube of approximately 160 microns inner and 170 microns outer diameter and the length of the tube5is approximately 150 millimeters. Apertures1704,1706may be laser drilled for the first quarter or proximal end, and last quarter or distal end, of the protective sheath5, covering approximately 4.5% of the surface area of the protective sheath5. In this embodiment, there are no apertures in the middle portion of the sheath5.

In one embodiment, a total of 12,000 apertures1704,1706may be drilled, 600 on each end of the protective sheath5. In one straight line at the proximal and distal ends, 1500 apertures of approximately 15 μm diameter are drilled with 50 μm distance between the apertures. This pattern may be repeated around the circumference of the tubing at approximately 45 degrees for a total of 8 lines of apertures along the length of the protective sheath5. The apertures1704,1706facilitate penetration of the sterilization agent from either end of the protective sheath5and allow sufficient diffusion of the sterilization agent to the middle half of the sheath5. The solid surface of the central portion of the sheath5(e.g., the section without apertures) offers stiffness and improves the manipulation and management of the individual highly flexible connecting elements3inserted into the protective sheath5during deployment and implantation.

FIG. 18illustrates approximate dimensions in centimeters (cm) for one embodiment of the system illustrated inFIG. 1, whileFIG. 19illustrates approximate dimensions for one embodiment of the system illustrated inFIG. 5. Other dimensions may be used depending on the particular application involved.

In other exemplary arrangements, connecting elements3may be micro fiber-optic cables for optical stimulation connected to different types of electrodes, such as thin film longitudinal intrafascicular electrodes (tfLIFE), transverse intrafascicular multichannel electrodes (TIME), flat interfaced nerve electrodes (FINE), and other electrode configurations or combinations of two different electrode configurations as would be well understood in the art.

A multi-electrode lead, multi-lead multi-electrode management system, and/or method of making a multi-electrode lead in accordance with the teachings of the present disclosure may be useful in one or more ways, including but not limited to:1. Multi-site gastric muscle/enteric nerve stimulation, recording and simultaneous stimulation and recording for treatment of gastroparesis, obesity, dysmotility and other gastric disorders;2. Multi-site stimulation of peripheral, cranial and spinal nerves for pain management;3. Multi-site stimulation of peripheral nerves for sensory feedback from prostheses or other external device with sensing elements;4. Multi-site recording from peripheral nerves for identifying multiple motor intents for potential use in control of prostheses;5. Multi-site stimulation of multiple muscles, such as intercostal muscles, abdominal muscles and diaphragm for respiratory assistance;6. Multi-site stimulation of phrenic nerves (left and right) for phrenic pacing for respiratory assistance;7. Multi-site stimulation of nerves for functional electrical stimulation after paralysis for activities such as hand grasp, pinch, standing, walking;8. Multi-site recording from multiple muscles using implanted electrodes for control of prostheses;9. Multi-site recording and/or stimulation of nerve or muscle tissue involved in the control of bladder and/or bowel function; and10. Multi-site recording and/or stimulation of nerve or muscle tissue involved in the control of the spleen or other organs involved in the immune system or other systems that are innervated by autonomic nervous system tissue.

The multi-electrode lead, multi-lead multi-electrode management system, and/or method of making a multi-electrode lead of the present disclosure in some arrangements may provide solutions for various practical hurdles posed by the commercially available multi-electrode leads. For example, current commercially available multi-electrode leads are typically a single macro lead that connects to electrode contacts that are evenly placed in concentric circles. This type of configuration of lead is not possible to implant in micro structures such as peripheral or cranial nerves or implanting in soft movable structures such as gastric muscles. The proposed packaging process for multi-electrode systems of the present disclosure, however, would facilitate in some arrangements targeting peripheral or cranial nerves, gastric and other nerve or muscle tissues that are spatially distributed over a large area or span various organs.

In another example, in commercially available multi-electrode leads, the inter-electrode distance is pre-determined. Intraoperatively, the only way the inter-electrode distance can be changed is by choosing different pairs of electrodes. In the proposed multi-electrode lead configuration of the present disclosure, however, there is in some arrangements full flexibility of specifying the intra-electrode distance at the time of implantation.

In a further example, packaging according to the teachings of the present disclosure in some arrangements can prevent or minimize entanglement of individual connecting elements.

Additionally, packaging according to the teachings of the present disclosure in some arrangements allows management of the lead and connecting elements during a surgical procedure.