Patent Application
20090326608
The present application is generally directed to programming an implantable pulse generator to provide an electrical stimulation therapy to a patient by successively shifting a locus of electrical stimulation.
Neurostimulation systems are devices that generate electrical pulses and deliver the pulses to nerve tissue to treat a variety of disorders. Neurostimulation systems generally include a pulse generator and one or more leads. The pulse generator is typically implemented using a metallic housing that encloses circuitry for generating the electrical pulses, control circuitry, communication circuitry, a rechargeable battery, etc. The pulse generation circuitry is coupled to one or more stimulation leads through electrical connections provided in a “header” of the pulse generator. Specifically, feedthrough wires typically exit the metallic housing and enter into a header structure of a moldable material. Within the header structure, the feedthrough wires are electrically coupled to annular electrical connectors. The header structure holds the annular connectors in a fixed arrangement that corresponds to the arrangement of terminals on a stimulation lead.
Spinal cord stimulation (SCS) is an example of neurostimulation in which electrical pulses are delivered to nerve tissue in the spine typically for the purpose of chronic pain control. Other examples include deep brain stimulation, cortical stimulation, cochlear nerve stimulation, peripheral nerve stimulation, vagal nerve stimulation, sacral nerve stimulation, etc. While a precise understanding of the interaction between the applied electrical energy and the nervous tissue is not fully appreciated, it is known that application of an electrical field to spinal nervous tissue can effectively mask certain types of pain transmitted from regions of the body associated with the stimulated nerve tissue. Specifically, applying electrical energy to the spinal cord associated with regions of the body afflicted with chronic pain can induce “paresthesia” (a subjective sensation of numbness or tingling) in the afflicted bodily regions. Thereby, paresthesia can effectively mask the transmission of non-acute pain sensations to the brain.
Also, each exterior region, or each dermatome, of the human body is associated with a particular spinal nerve root at a particular longitudinal spinal position. The head and neck regions are associated with C2-C8, the back region extends from C2-S3, the central diaphragm is associated with spinal nerve roots between C3 and C5, the upper extremities correspond to C5 and T1, the thoracic wall extends from T1 to T11, the peripheral diaphragm is between T6 and T11, the abdominal wall is associated with T6-L1, lower extremities are located from L2 to S2, and the perineum from L4 to S4. In conventional neurostimulation, when a patient experiences pain in one of these regions, a neurostimulation lead is implanted adjacent to the spinal cord at the corresponding spinal position. By example, to address chronic pain sensations that commonly focus on the lower back and lower extremities using conventional techniques, a specific energy field is typically applied to a region between vertebrae levels T8 and T12.
Positioning of an applied electrical field relative to a physiological midline is also important. Nerve fibers extend between the brain and a nerve root along the same side of the dorsal column as the peripheral areas the fibers represent. Pain that is concentrated on only one side of the body is “unilateral” in nature. To address unilateral pain, electrical energy is applied to neural structures on the side of a dorsal column that directly corresponds to a side of the body subject to pain. Pain that is present on both sides of a patient is “bilateral.” Accordingly, bilateral pain is addressed through application of electrical energy along both sides of the column and/or along a patient's physiological midline.
Accordingly, at any particular vertebral level, it is possible to stimulate a number of nerve fibers and structures of the spinal cord and, thereby cause the patient to experience paresthesia over several areas of the patient's body. Clinicians typically attempt to define a neurostimulation therapy by stimulating nerve fibers associated with locations of chronic pain while excluding nerve fibers associated with non-afflicted locations. To define an acceptable neurostimulation therapy, a clinician selects values for a number of programmable parameters. For example, the clinician may select parameters defining pulse amplitude, pulse width, and pulse frequency. The clinician may also select electrode polarities for deliver of the pulses. The process of selecting values for the parameters can be time consuming and may require a great deal of trial and error before an acceptable therapeutic program is identified. In some cases, the clinician may test various electrode polarity combinations by manually specifying each combination based on intuition or some idiosyncratic methodology. The clinician may record notes on the efficacy and side effects of each combination after delivery of stimulation via that combination. In this manner, the clinician is able to later compare and select from the tested combinations.
In one embodiment, a method assists programming a single-source pulse generator to apply stimulation pulses to tissue of a patient using a controller device by a clinician. The method comprises: (i) defining a set of unique electrode combinations in the controller device, each electrode combination of the set comprising at least one cathode and at least one anode, each electrode combination within the set providing a unique locus of stimulation for a single stimulation pulse applied at a base location relative to loci of stimulation of other electrode combinations of the set applied at the base location, the set of unique electrode combinations defining a two-dimensional range of multiple loci of stimulation along longitudinal and lateral directions; (ii) providing one or more user interfaces to the clinician to control pulse generation and delivery by the single-source pulse generator, the one or more user interfaces comprising one or more controls that enable the clinician to relocate a locus of stimulation; and (iii) processing input from the clinician related to relocation of a locus of stimulation, the processing comprising (i) automatically selecting an electrode combination from the set, and (ii) automatically modifying an electrode combination used by the single-source pulse generator to deliver electrical stimulation pulses to the selected electrode combination.
The foregoing has outlined rather broadly certain features and/or technical advantages in order that the detailed description that follows may be better understood. Additional features and/or advantages will be described hereinafter which form the subject of the claims. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the appended claims. The novel features, both as to organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the appended claims.
Implantable pulse generator 150 typically comprises a metallic housing that encloses pulse generating circuitry, control circuitry, communication circuitry, battery, etc. of the device. An example of pulse generating circuitry is described in U.S. Patent Publication No. 20060170486 entitled “PULSE GENERATOR HAVING AN EFFICIENT FRACTIONAL VOLTAGE CONVERTER AND METHOD OF USE,” which is incorporated herein by reference. A microprocessor and associated charge control circuitry for an implantable pulse generator is described in U.S. Patent Publication No. 20060259098, entitled “SYSTEMS AND METHODS FOR USE IN PULSE GENERATION,” which is incorporated herein by reference. Circuitry for recharging a rechargeable battery of an implantable pulse generator using inductive coupling and external charging circuits are described in U.S. patent Ser. No. 11/109,114, entitled “IMPLANTABLE DEVICE AND SYSTEM FOR WIRELESS COMMUNICATION,” which is incorporated herein by reference. An example of a commercially available implantable pulse generator is the EON® pulse generator available from Advanced Neuromodulation Systems, Inc. Although an implantable pulse generator is described according to some embodiments, other pulse generators could be similarly programmed. For example, an external trial stimulator may be programmed according to alternative embodiments.
One or more stimulation leads 160 are electrically coupled to the pulse generating circuitry of pulse generator 150, e.g., through the electrical contacts of the header of pulse generator 150 or through a lead extension device. As shown in
As shown in
When used to initially program implantable pulse generator 150 or to subsequently revise such programming, the clinician selects values for a number of programmable parameters in order to define the stimulation therapy to be delivered to a patient. The clinician may select pulse amplitude, pulse width, pulse frequency, and electrode combinations. The clinician may also combine multiple sets of such stimulation parameters to define one or more “multi-stimulation set” programs, which are known in the art. The multi-stimulation set programs may allow pain in distinct regions of the body to be treated simultaneously, to permit differences in therapy to be delivered at different times of the day or for different patient activities, etc. Controller 110 preferably stores software code defining a number of interfaces to facilitate the selection of stimulation parameters and stimulation programs. The screens of the various interfaces are provided to the clinician via display 112 and the clinician inputs data relevant for the various screens using controls 111 and/or the touch-screen functionality of display 112. Upon selection of the respective stimulation parameters, controller 110 communicates the stimulation parameters to pulse generator 150 using suitable communication circuitry (preferably via a wireless RF signal) as is known in the art.
In preferred embodiments, controller 110 stores software code that permits a clinician to test a number of electrode combinations in an efficient manner. The software enables the clinician to shift a locus of stimulation longitudinally and laterally. For example, the clinician may attempt to relocate or move the locus of the stimulation rostrally along the spinal cord in order to change the perceived location of paresthesia in the patient. The clinician may relocate the locus of stimulation by selecting one or more graphical controls of a user interface. The software processes input from the user interface and automatically modifies the electrode polarities used to apply the stimulation pulses to nerve tissue in response to such input. As multiple movements (rostrally, caudally, left relative to midline, right relative to midline) are selected by the clinician, the software automatically applies different patterns of electrode polarities thereby providing respective incremental movements in the locus of stimulation.
Electrode combination 206 is the same as electrode combination 201 except that electrode combination 206 is shifted upward along the stimulation lead by one electrode position. That is, electrode combination 206 comprises cathode 206a at the fifth electrode position and anode 206b in the sixth electrode position while electrode combination 201 comprises cathode 201a at the fourth electrode position and anode 201b at the fifth electrode position. As can be appreciated, at this point, further upward shifts may occur from electrode combination 206 by utilizing the other electrode combinations 202-205 shifted up by one electrode position relative to the positions shown in
Other electrode combinations may be employed according to alternative embodiments.
The locus of stimulation can also be shifted in a lateral manner by employing successive unique electrode combinations.
Representative embodiments preferably enable a clinician to move the locus of stimulation laterally and longitudinally along two adjacent columns of electrodes by defining a set of electrode combinations for such movement.
Suppose electrode combination (X,Y) is the current electrode combination. To move the locus of stimulation to the “right,” electrode combination (X+1, Y) would be selected according to the indexing used in
In preferred embodiments, software of controller 110 provides one or more interfaces that allow a clinician to move the locus of stimulation using a set of electrode combinations by selecting suitable graphical controls of the interface(s).
As shown in
Some embodiments are advantageous for programming a single-source stimulation system. As used herein, a single source-stimulation stimulation is a stimulation system that provides a single output pulse at any given time. Some embodiments are advantageous for such systems, because some embodiments provide a methodology for a clinician to incrementally shift the locus of stimulation between electrodes without requiring multiple simultaneous stimulation pulses.
In other embodiments, shifting of the locus of stimulation using different electrode combinations may be applied initially. After identifying multiple electrode combinations that possess loci of stimulation “close” to a desired loci, current “fractionalization” or “steering” may occur to further refine the locus of stimulation between such electrode combinations. For example, two closely-timed stimulation pulses on the identified electrode combinations may provide a time-domain summation to adjust the locus of stimulation. Alternatively, depending upon device capabilities, two simultaneous pulses may be applied to the identified electrode combinations. By utilizing different electrode combinations and, then, applying current fractionalization or steering, the programming process may occur in a more efficient manner. That is, the clinician may utilize the electrode combinations to more quickly identify an approximate “best” region for stimulation and then fine-tune stimulation within that region using pulse fractionalization or steering.
In another embodiment, shifting of the loci of stimulation for respective stim sets of a multi-stim set program may occur by incrementally shifting respective sets of electrode polarities pertaining to the respective stim sets of the program. As used herein, a “stim set” refers to a set of parameters which define a pulse to be generated and how the pulse is to be delivered. Each stim set may define a pulse amplitude, a pulse width, (optionally a pulse delay), an electrode combination, etc. The multi-stim set program includes multiple such stim sets. Execution of a multi-stim set program by a pulse generator involves repeatedly generating and delivering pulses in a successive manner for each stim set of the program. The generation of pulses in this manner may occur according to a program frequency.
User interface 800 (shown in
Although certain representative embodiments and advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate when reading the present application, other processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the described embodiments may be utilized. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.
This application claims the benefit of U.S. Provisional Application No. 61/075,506, filed Jun. 25, 2008, the disclosure of which is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 61075506 | Jun 2008 | US |
