NEUROMODULATION

FIELD OF THE INVENTION

[0001] Embodiments of the claimed invention relate to systems and methods for pain treatment, and in one embodiment, a system and method for neuropathic pain treatment and the treatment of positive symptoms caused by nerve injury such as tinnitus using neuromodulation.

BACKGROUND ART

[0002] Neuropathic pain is caused by abnormal nerve signaling in the nervous system and, as a result, often does not respond to conventional pain relief strategies. Currently, both central and peripheral neuromodulation are the most effective treatments of neuropathic pain.

[0003] Neuromodulation works by either actively stimulating nerves to produce a natural biological response, or by applying targeted pharmaceutical agents in tiny doses directly to the site of pain. With respect to the latter, neurostimulation devices involve the application of electrodes proximate to the peripheral nerves or the spinal cord. Peripheral nerve field stimulation (PNFS) and peripheral nerve stimulation (PNS) involves placing the leads just under the skin in a painful area of proximate to the nerves involved in pain. [0004] In spinal cord stimulation (SCS), soft, thin wires with electrical leads on their tips are placed through a needle in the back proximate to the spinal column. The leads are placed through a needle inserted in the back. A small incision is then made and a tiny, programmable generator is placed in the upper buttock or abdomen (under the skin), which emits electrical currents to the spinal column.

[0005] In either case, low- voltage electrical current passes from the generator to the nerve and stimulates the pain inhibition pathways. Neurostimulation does not eliminate pain, but rather creates a feeling of pleasant paraesthesia in the implantation area (PNS and PNFS). This results in a masking of the pain.

[0006] FIG. 1 illustrates a conventional spinal cord stimulation system. As described above, electrical leads 120 are implanted into the epidural space proximate to the spinal cord 110. Electrical pulses are generated by generator 130, implanted in the upper buttock, and passed through electrical leads 120, in order to stimulate spinal cord 110. This creates a pleasant paraesthesia in the area of pain.

[0007] These implantable neuromodulation systems and expensive and not exempt from placement complications. However, in certain cases, the indication of implantable neuromodulation systems is fully justified, as there are no other treatment alternatives. One of the problems of peripheral nerve neuromodulation is the continuous movement of the muscles and nerves around which the leads are implanted, which could result in wire leads changing position. Such change in position can reduce the amount of pain relief. Thus, it is essential that the distance between the electrode and nerve remains constant. [0008] Such a complication is illustrated in FIGS. 2 and 3. As shown in FIG. 2, lead 210 is implanted proximate to nerve 230, and generates electrical pulses 220 to stimulate nerve 230. When the patient is at rest, lead 210 and nerve 230 remain in this position. FIG. 3 illustrates the positioning of lead 210 and nerve 230 during movement. In such a case, separation is created between lead 210 and nerve 230, and electrical pulses 220 are unable to successfully stimulate nerve 230 due to this separation. This situation is very common, and in these cases, the technique does not work properly.

SUMMARY OF THE INVENTION

[0009] Thus, there still exists a need for systems and methods for neuropathic pain treatment that do not displace with muscle movement and that do not require leads. In view of the foregoing, an embodiment of the present invention provides a wireless micro-neurostimulator is provided that is comprised of microelectrode(s) placed inside nerve(s) for neurostimulation, to treat peripheral neuropathic pain and other lesions related to the nerve. The micro-neurostimulator is implanted percutaneously and placed by ultrasound-guided puncture.

[0010] The micro-neurostimulator can be recharged by induction charging, which allows recharging through the skin without wires penetrating the skin. Because the device is placed inside the nerve, however, the need for recharging is minimized. Advantageously, there is limited displacement of the micro-neurostimulator within the nerve due to muscle movement, and constant stimulus is provided because the device is moved with the nerve.

[0011] Another embodiment of the invention relates generally to systems and methods for neuropathic pain treatment using neuromodulation. According to one embodiment of the claimed invention, a system for neuropathic pain treatment using neuromodulation is provided comprising a leadless electrode configured to be implanted inside a nerve and to provide electrical stimulation to the nerve. According to another embodiment of the claimed invention, a method for neuropathic pain treatment using neuromodulation is provided. The method comprises implanting a leadless electrode inside a nerve, and applying electrical stimulation from the leadless electrode to the nerve. [0012] Still other aspects, features and advantages of the present invention are readily apparent from the following detailed description, simply by illustrating a number of exemplary embodiments and implementations, including the best mode contemplated for carrying out the present invention. The present invention also is capable of other and different embodiments, and its several details can be modified in various respects, all without departing from the spirit and scope of the present invention. Accordingly, the drawings and descriptions are to be regarded as illustrative in nature, and not as restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The present invention will be understood more fully from the detailed description given below and from the accompanying drawings of various embodiments of the invention, which, however, should not be taken to limit the invention to the specific embodiments, but are for explanation and understanding only.

[0014] FIG. 1 is an illustration of a conventional spinal cord stimulation system.

[0015] FIG. 2 is a diagrammatic representation of a conventional implanted lead for neurostimulation when the patient is at rest.

[0016] FIG. 3 is a diagrammatic representation of a conventional implanted lead for neurostimulation when the patient is in movement. [0017] FIG. 4 is an illustration of a leadless electrode implanted into a nerve in accordance with an embodiment of the invention.

[0018] FIG. 5 is a diagrammatic representation of a leadless electrode implanted into a nerve in accordance with an embodiment of the invention. [0019] FIG. 6 is a flowchart illustrating a method for neuropathic pain treatment using neuromodulation according to an embodiment of the invention.

[0020] FIG. 7 illustrates the use of a micro-optics cannula for monitoring the correct position of a micro-implantable stimulator according to an embodiment of the invention. DETAILED DESCRIPTION

[0021] Systems and methods for neuropathic pain treatment using neuromodulation are described. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the exemplary embodiments. It is apparent to one skilled in the art, however, that the present invention can be practiced without these specific details or with an equivalent arrangement.

[0022] Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views, FIG. 4 is an illustration of a leadless electrode 420 implanted into a nerve 410 in accordance with an embodiment of the invention. Similarly, FIG. 5 is a diagrammatic representation of leadless electrode 420 implanted into a nerve 410 in accordance with an embodiment of the invention. [0023] Leadless electrode 420 of FIGS. 4 and 5 may be, for example, a wireless microelectrode, micro-neurostimulator and/or miniaturized electrode. Thus, leadless electrode 420 provides a fully autonomic system not requiring tunneled or externalized wires. [0024] Leadless electrode 420 is placed inside nerve 410 in order to treat peripheral neuropathic pain and other lesions related to the nerve. Leadless electrode 420 may be implanted percutaneously at the intraepineural level, and may be placed by, for example, ultrasound-guided puncture.

[0025] Leadless electrode 420 can be charged and/or recharged by induction charging, which allows recharging through the skin without wires penetrating the skin. This minimizes the risk for infection. Because leadless electrode 420 is placed inside nerve 410, however, the need to recharging is minimized. In other words, leadless electrode 420 has very low energy requirements due to the intraepineural implantation.

[0026] Advantageously, leadless electrode 420 is not displaced due to muscle movement, as it is placed directly inside nerve 410. In addition, constant stimulus is provided because leadless electrode 420 is positioned directly inside nerve 410.

[0027] FIG. 6 is a flowchart 600 illustrating a method for neuropathic pain treatment using neuromodulation according to an embodiment of the invention. The method can be used to implement the systems described with respect to FIGS. 4 and 5, for example. At processing block 610, a leadless electrode is implanted inside a nerve. Optionally, the nerve can first be located using an ultrasound. In one embodiment, the ultrasound is used in conjunction with an optical cannula, as shown in FIG. 7. However, the use of the optical cannula is not always necessary. [0028] The leadless electrode can be implanted percutaneously. In one embodiment, the leadless electrode is placed at the intraepineural level. The leadless electrode can be a wireless microelectrode and/or a micro-neurostimulator.

[0029] At processing block 620, electrical stimulation is applied from the leadless electrode to the nerve. The electrical stimulation from the leadless electrode to the nerve can be provided constantly and/or continuously. In one embodiment, the leadless electrode is further charged and/or recharged. This can be done, for example, by induction charging through the skin, such that incision is not necessary.

[0030] Although shown and described with respect to a single nerve and a single leadless electrode, it is contemplated that any number of leadless electrodes can be implanted into any number of nerves. For example, two or more leadless electrodes can be implanted into a single nerve. In another example, one or more leadless electrodes can be implanted in two or more nerves.

[0031] The present invention has been described in relation to particular examples, which are intended in all respects to be illustrative rather than restrictive. Those skilled in the art will appreciate that many different combinations of materials and components will be suitable for practicing the present invention.

[0032] Other implementations of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. Various aspects and/or components of the described embodiments may be used singly or in any combination. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.