EXTENSION OF A PREVIOUSLY IMPLANTED LEAD OR ELECTRODE

A system and methods and disclosed for extending a previously implanted lead for connecting to an internal pulse generator (IPG), or for extending the lead to a new tissue target.

FIELD OF THE INVENTION

The field of the invention is the extension of a previously implanted lead or electrode to a tissue target.

BACKGROUND

Neuromodulation devices with a lead to a tissue target still face patient and clinician adoption hurdles. The trial lead is a major effort to demonstrate for a patient the potential result of a permanently implanted device. The trial lead is stimulated by various means, often from outside the body. The prior art trial lead is a temporary lead, often connected to an external pulse generator percutaneously. The trial lead is implanted surgically or otherwise and then removed from the body after a period of days. The patient and clinician then consider the desirability of implanting a permanent lead which would be connected to an implanted internal pulse generator (IPG). If the patient elects to have a permanent lead, a second surgical procedure is required for implanting a second lead at the tissue target. This scenario requires two procedures in which a permanent lead ends up implanted at the tissue target. Disturbing the tissue with a surgical procedure a second time can irritate that tissue and the second procedure also subjects the patient to infection risk. And, of course, the second procedure creates more expense. What is needed is a system and method for implanting at least one lead which can serve as the trial lead for a short period and then remain in place if the patient and clinician so choose: that is, the previously implanted lead can be extended and connected to an IPG.

ASPECTS OF THE INVENTION

The present invention enables the clinician to convert a previously implanted trial lead to a permanent lead so that the previously implanted lead can remain in place and be connected to an IPG and be used as a permanent lead for a fully implanted and permanent system. A lead which is well adapted to be the primary lead in the invention herein is the helical wire rope structure electrode is described in PCT/US2021/33007 (PCT '007) and which is fully adopted and incorporated as if set forth entirely herein. PCT '007 does not disclose connecting the primary lead2to an IPG3or other devices. Additionally, the system can also comprise traditional leads which existed prior to that disclosed in PCT '007.

The invention herein enables the clinician to convert a previously-implanted trial lead to a permanent lead. First, at least one lead1has been previously implanted as a trial lead in accordance with the disclosure in PCT '007 and can be powered with an external power source either through a percutaneous tail extending through the skin, or with a transcutaneous connection enabled by a collector just under the skin. If the patient elects for implantation of a permanent system, then the physician makes an incision near the proximal end of the lead, connects the proximal end to another lead or to another device which is outside the scope of this invention. There are numerous methods for these other leads and/or devices to be placed, as approved by regulatory bodies and as performed by clinicians.

Beyond the description of primary lead2shown in PCT '007, the lead has a “pin” connector end (elements7and17inFIG.4A) which can be passed through the same delivery needle as the helical wire rope structure electrode (element2inFIG.4A). During the trial period, electrical energy may be coupled directly into the pin end7placed in the subcutaneous tissue or, alternatively, a secondary helical wire rope structure with a socket (elements4and13inFIG.4A) may be reversibly connected to the needle delivered first helical wire rope structure with a pin. The latter option may provide a larger charge injection interface for improved subcutaneous coupling as compared to the pin only version.

Each primary lead has its own primary connector on its proximal end. With, say, a socket connector on its proximal end, this primary connector may then be connected to a pin (complementary connector) attached to a lead to one of the following: a commercially available adapter, an IPG, any other type of stimulator, or a helical wire rope structure.

Various embodiments of the system comprise a primary connector which is secured to the proximal end of a primary lead before it is implanted as a trial lead. The primary connector may comprise an internal cavity configured to receive and trap an expanding feature on a dockable connector on a separate secondary lead connected to the IPG, and may also comprise a seal integrated at the entry of the docking cavity to prevent tissue ingrowth and preserve the integrity of the interface.

Each type of indirect connection can be enclosed within a sheath, that is, a sacrificial sleeve, to be pierced or removed prior to placement of the complementary connector which inhibits cellular or fluid entry and maintain a connector for future mating.

The primary lead herein may be connected to a primary connector by an element which is selected from the group consisting of a boa-spring, a loop-through, and/or a direct welded connection to the primary lead or parts thereof to secure the primary lead electrically and mechanically to the indirect connector.

The system1herein inFIGS.1A-1Dis depicted in embodiments with the primary lead being a helical wire rope structure, although other embodiments of the system incorporate a traditional wire lead, i.e., non-helical wire rope structure. All of the embodiments inFIGS.1A-1Dare perspective views of the invention herein with a pin for insertion into a socketed device such as an IPG.FIG.1Ais an embodiment with a single primary and a single secondary lead.FIG.1Bis an embodiment with two primary and two secondary leads.FIG.1Chas four sets of primary and secondary leads with a pin connected to an IPG having a socket.FIG.1Dis a perspective of a similar set up with returns co-located on each of the secondary leads. Other embodiments, not shown, allow connections for more than four sets of primary and secondary leads to an IPG. In all these embodiments, the diameter of the primary connector is small enough to be injected through a cannula (e.g., 14-20 ga) with the primary lead, in one embodiment the diameter being 1 mm or less. In these embodiments, the system is configured to transfer energy from an IPG or other device to at least one tissue target wherein the system comprises at least one primary lead2having distal and proximal ends2a,2b, a primary connector4attached to each said proximal end, at least one secondary lead5which may be insulated except at its first and second ends5a,5b, a complementary connector7attached to each said first end, and a secondary connector8attached to each said second end such that, when the distal end is positioned near said at least one tissue target and the primary and complementary connectors are joined, the system is able to provide at least one completed electrical connection between a tissue target and an IPG. Each secondary lead may, in some embodiments, be grouped into a larger housing or insertion pin9for connecting to the IPG. A return10has one end10aconnected to a contact15and another end10bconnected to a return secondary connector14. The primary and complementary connectors can be any shape and design so that each connects to the other securely. For example, the primary connector can be a socket and the complementary connector can be a pin, and vice versa, and other designs can be employed in other embodiments.FIG.1Edepicts one embodiment of the secondary connector8connected to the second end5bof the secondary lead5and the return secondary connector14connected to an end10bof the return10.

FIG.2is a perspective view of an embodiment of the system with a socket for connecting to a pin device such as a lead, andFIG.2Ais a closer view of the socket. The difference betweenFIG.1AandFIGS.2and2Ais that the insertion pin9ofFIG.1Ais a socket9A, and all other elements ofFIGS.2and2Aare the same as labeled inFIG.1A. That is, the embodiment ofFIG.2can connect to a pin of another device such as a previously implanted lead. Other embodiments, not pictured, have multiple primary and second leads which are the same as the single primary and second lead ofFIG.2. These other embodiments would be similar toFIGS.1B,1C and1D, except that a socket9A is attached instead of a pin as inFIGS.1A-1D.FIG.2Ademonstrates schematically that the secondary lead5is connected to

FIG.3is a schematic of the invention herein in an embodiment with two secondary leads5and two returns10with a complementary connector7to a secondary lead to an IPG3having an opening3afor connection to the system herein via connectors8(A, B) and14(R(A) and R(B)). The secondary leads are connected to two secondary connectors8which connect to recessed connectors11(A, B) in an opening3ain the IPG3. The two returns are connected to return secondary connectors14and connect to additional connectors for the returns12.

FIG.4is a schematic of the invention in an embodiment with a socket with single primary and secondary leads and a return with a socket for connecting to a device having a pin. This embodiment differs in character from that inFIG.3(apart from reduction of primary and secondary leads from two to one) in that a socket9A has been substituted for the pin9ofFIG.3.

FIG.5Ais a cross-section of an embodiment of a primary connector4, here a socket, and a complementary connector7, here a pin, in a pre-insertion position. A slot4aallows expansion of the socket for insertion of the pin.FIG.5Bis a cross section during insertion, andFIG.5Cis post-insertion. A docking sleeve13will be pushed to the left to enclose the connectors and to keep them together.

FIG.6Ais a section view of one embodiment of a connection between the complementary connector7(pin) and the primary connector4(socket) before the docking sleeve13has been moved to lock them into place, andFIG.6Bis after the docking sleeve has been moved to the locked position. The primary lead2is connected to the complementary connector by any secure attachment17.FIGS.6C and6Dare additional embodiments

A group of embodiments of the invention establishes a direct connection of a previously implanted primary lead anywhere along its length to a lead to an IPG. A “direct connection” in this usage means no modification of the primary lead is needed. The mechanism for a direct connection is selected from the group consisting of a docking coil assembly, a hook and anvil, and a barracuda clip. Other mechanical connectors within this group may also be used.FIGS.7A and7Bshow one of the numerous possible embodiments of the direct connector. The direct connector, comprising a corkscrew and connection needle, is configured for insertion through a cannula (e.g., 14-20 ga) and for mating connections to be made in vivo. Serrations or jaws on the direct connectors provide a secure electrical and mechanical connection.

Via a “direct connector to socket adapter” extension scheme, a formerly placed lead with no additional modifications can be directly connected in vivo via a needle based procedure, with multiple connector designs described herein (see method 1). The lead can also be modified to include an integrated ‘pin’ connector, with methods and designs of securing the wire structure electrode material to the connectors described herein (see method 2). The ‘socket’ connector is also needle deliverable and extends the wire structure electrode electrical path once connected to the ‘pin’ end and provides an extended end for other devices to be connected to (see method 3).

FIGS.7A and7Bdepict an embodiment of a direct connector in an embodiment with a corkscrew18, and making a connection with a primary lead inFIG.7B. The corkscrew18is securely affixed to a connection needle19with a rounded tip20, and is inserted through a delivery device21to allow the tip and corkscrew to attach to the primary lead2. The connection needle is attached to an secondary lead5.

FIG.8is an image of two sets of primary and secondary leads connected to an IPG as implanted in an animal.

A zone of innervation can include nerve fibers which are connected to the spinal cord at different vertebra. So, in various embodiments of the invention, the number of leads for interface with the dorsal root ganglion can include two for each vertebra (bilateral) times the number of vertebra where the nerves for that zone attach to the spinal cord for a total of, say, four or six leads.

Delivery methods are conducted either immediately after placement of the electrode (unmodified or modified), or may be conducted at a later time following electrode implant. Devices to achieve the delivery are a series of cannulas with inner diameter larger than that of the cannula deliverable connectors and includes a holding mechanism that temporally secures the target connector in place. The holding mechanism has “soft jaws” that clamp around the target connector and restricts axial movement while the interconnect is formed. Once formed, the holding mechanism releases, with the delivery device retracted to allow full deployment of the “extension” devices described.

It must also be understood that the primary lead2and the secondary lead5may be separate devices. A first device comprises a primary lead2having distal and proximal ends2a,2band a primary connector4attached to said proximal end, said device configured for injecting fully into a body through a delivery device, and further configured such that the distal end2amay be placed near a tissue target and said proximal end2ais configured to pick up energy from a source internal or external to the body as a trial lead, and said primary connector4is available to be connected to a complementary connector7, which may be connected at the same time as the first device is implanted, or at a later time. A second device comprises at least one secondary lead5having first and second ends5a,5b, a complementary connector7attached to each said first end5a, and a secondary connector8attached to each said second end5band configured for connection to an IPG3or other device, the complementary connector7configured to be connected to a primary connector4on a proximal end2bof a primary lead2previously placed in a body.

In another embodiment, the second lead comprises a lead such as a helical wire rope structure with a socket connector.

Methods

The system may be placed using the following methods.

Method 1 comprises the steps of (1) placing near a tissue target a primary lead with a primary connector at the proximal end, (2) awaiting tissue ingrowth and testing functionality of the primary lead in a wireless stimulation setup, (3) tunneling to the primary connector end (under fluoroscopy or ultrasound) and forming a secure hold with the delivery system on to the primary connector, (4) placing the secondary lead with a complementary connector into a cannula and establishing interconnection with the primary connector and (5) disengaging the holding mechanism and retracting the delivery cannula to leave behind an extension with an exposed connector end to which additional devices and adapters may then be connected.

Method 2 comprises the steps of (1) placing a primary lead or electrode near a tissue target, (2) awaiting tissue ingrowth and testing its functionality, (3) forming a direct connection (e.g., with a corkscrew connector) to the proximal end of the primary lead using a minimally invasive needle based approach by tunneling to the target (under fluoroscopy or ultrasound), and (4) after placing the direct connector, removing the delivery cannula and connecting an adaptor or implantable stimulation device to be placed in a subcutaneous pocket.

Method 3 comprises the steps of either Method 1 or 2 also immediately after placement of the devices without a period of ingrowth.

Method 4 comprises the steps of Methods 1, 2, or 3, performed in an open cut down, although the minimally invasive cannula based methods are preferable for patient safety and comfort. The placement of an IPG to which the primary lead is connected is performed as an open cut down surgery.

Method 5 comprises the steps of Method 1 or 2 and the additional step of evaluating the usefulness of each of the implanted primary leads and connecting a subset of the implanted primary leads to a secondary lead.