Implantable microstimulators with programmable multielectrode configuration and uses thereof

Abstract

Miniature implantable stimulators (i.e., microstimulators) with programmably configurable electrodes allow, among other things, steering of the electric fields created. In addition, the microstimulators are capable of producing unidirectionally propagating action potentials (UPAPs).

What is claimed is:  
     
         1 . A microstimulator capable of being electrically positioned, comprising: 
 at least two programmably configurable electrodes for applying steerable electric fields;    electrical circuitry electrically connected to the at least two electrodes, wherein the electrical circuitry generates stimulation pulses applied by the electrodes, which stimulation pulses are variable to create steerable electric fields;    programmable memory connected to the electrical circuitry, which programmable memory stores stimulation parameters determining the activated electrodes and the stimulation pulses generated by the electrical circuitry and applied by the activated electrodes; and    a power source connected to the electrical circuitry, which power source provides operating power to the microstimulator.    
     
     
         2 . The microstimulator of  claim 1  further comprising a multiplicity of programmably configurable electrodes for applying steerable electric fields.  
     
     
         3 . The microstimulator of  claim 2  wherein the electrodes are positioned along and around the microstimulator.  
     
     
         4 . The microstimulator of  claim 3  wherein the electric fields are steerable radially around the microstimulator and longitudinally along the microstimulator.  
     
     
         5 . The microstimulator of  claim 1  wherein the electrodes are programmably configurable prior to implantation and after implantation.  
     
     
         6 . The microstimulator of  claim 1  further comprising at least one hard-wired electrode.  
     
     
         7 . The microstimulator of  claim 1  further comprising a lead, wherein at least one of the electrodes is positioned on the lead.  
     
     
         8 . The microstimulator of  claim 7  wherein the lead is no longer than about 150 mm in length.  
     
     
         9 . The microstimulator of  claim 1  wherein each activated electrode is configured as one of an anode, cathode, and an open circuit.  
     
     
         10 . The microstimulator of  claim 9  further comprising at least one configurable group of electrodes comprising at least two activated electrodes.  
     
     
         11 . The microstimulator of  claim 9  wherein the stimulation parameters include controlling the amount of current flowing from at least one of the electrodes that is activated.  
     
     
         12 . The microstimulator of  claim 1  further comprising an external programmer that adjusts the stimulation parameters.  
     
     
         13 . The microstimulator of  claim 1  wherein the stimulation parameters are fixed.  
     
     
         14 . The microstimulator of  claim 1  further comprising at least one sensor that senses a physical condition of a patient.  
     
     
         15 . The microstimulator of  claim 14  wherein the sensed physical condition is used to adjust the stimulation parameters.  
     
     
         16 . The microstimulator of  claim 15  wherein the stimulation parameters are automatically adjusted.  
     
     
         17 . The microstimulator of  claim 1  wherein the stimulation parameters include controlling the amount of current flowing from at least one of the electrodes that is activated.  
     
     
         18 . The microstimulator of  claim 1  wherein the electrodes are programmed to unidirectionally propagate action potentials.  
     
     
         19 . The microstimulator of  claim 18  further comprising at least one lead and wherein at least one electrode is positioned on the at least one lead.  
     
     
         20 . The microstimulator of  claim 18  further comprising at least one cuff electrode wherein at least one electrode is positioned on the at least one cuff and the at least one cuff is attached to the microstimulator via a lead.  
     
     
         21 . The microstimulator of  claim 18  further comprising at least one cuff electrode wherein the at least one cuff electrode is incorporated into the microstimulator.  
     
     
         22 . The microstimulator of  claim 18  wherein the microstimulator is programmed to create a stimulation pulse with a plateau pulsewidth of about 10 μsec to about 5 msec and a decaying trailing phase with a fall time of about 50 μsec to about 5 msec and a charge recovery pulse with a plateau pulsewidth of about 50 μsec to about 10 msec and a decaying trailing phase with a fall time of about 50 μsec to about 5 msec.  
     
     
         23 . A microstimulator, comprising: 
 at least two programmably configurable electrodes for applying steerable electric fields;    means for generating stimulation pulses applied by the electrodes, which stimulation pulses are variable to create steerable electric fields, and which generating means are connected to the at least two electrodes;    means for storing stimulation parameters, which stimulation parameters determine the activated electrodes and the stimulation pulses applied by the activated electrodes, which storing means are connected to the means for generating stimulation pulses; and    means for providing operating power to the microstimulator, which power means are connected to the means for generating stimulation pulses.    
     
     
         24 . The microstimulator of  claim 23  wherein each activated electrode is configurable as one of an anode, cathode, and an open circuit.  
     
     
         25 . The microstimulator of  claim 24  further comprising at least one configurable group of electrodes comprising at least two activated electrodes.  
     
     
         26 . The microstimulator of  claim 24  wherein the stimulation parameters control the amount of current flowing from at least one of the activated electrodes.  
     
     
         27 . The microstimulator of  claim 23  further comprising means for adjusting the stimulation parameters.  
     
     
         28 . The microstimulator of  claim 23  further comprising means for sensing a physical condition of a patient.  
     
     
         29 . The microstimulator of  claim 28  wherein the sensed physical condition is used to adjust the stimulation parameters.  
     
     
         30 . The microstimulator of  claim 23  further including means for providing unidirectional propagation of action potentials.  
     
     
         31 . A method of electrically positioning a microstimulator, wherein the microstimulator comprises: 
 at least two programmably configurable electrodes for applying steerable electric fields,    electrical circuitry electrically connected to the electrodes, which electrical circuitry generates stimulation pulses applied by the electrodes,    programmable memory electrically connected to the electrical circuitry, which programmable memory stores stimulation parameters, and    a power source connected to the electrical circuitry, which power source provides operating power to the microstimulator;    said method comprising: 
 determining the electrodes to activate and the stimulation pulses to apply with the activated electrodes using the stimulation parameters stored in the programmable memory; and  
 generating the stimulation pulses using the electrical circuitry and based on the stimulation parameters, which stimulation pulses are variable to create steerable electric fields that electrically position the microstimulator.  
   
     
     
         32 . The method of  claim 31  further comprising adjusting the stimulation parameters to configure each activated electrode as one of an anode, cathode, and an open circuit.  
     
     
         33 . The method of  claim 32  further comprising adjusting the stimulation parameters to configure at least two activated electrodes into at least one configurable group of electrodes.  
     
     
         34 . The method of  claim 31  further comprising adjusting the stimulation parameters to steer the electric fields at least one of radially around the microstimulator and longitudinally along the microstimulator.  
     
     
         35 . The method of  claim 31  further comprising adjusting the stimulation parameters to control the amount of current flowing from at least one of the electrodes that is activated.  
     
     
         36 . The method of  claim 31  wherein the microstimulator further comprises at least one sensor for sensing at least one physical condition of a patient and the method further comprises sensing at least one physical condition of the patient.  
     
     
         37 . The method of  claim 36  further comprising using the sensed physical condition to adjust the stimulation parameters.  
     
     
         38 . The method of  claim 31  further comprising configuring the electrodes to provide unidirectional propagation of action potentials.