Abstract:
A method and apparatus for diagnosing and treating neural dysfunction is disclosed, which comprises taking the energy output from a high frequency generator module and delivering this energy as in a pulsed manner to a treatment electrode. In one exemplary embodiment, a temperature set point is utilized, and the pulses are modified to limit the energy delivered such that the temperature is limited. One exemplary method of modifying pulses includes reducing the amplitude of the pulses. Another exemplary method of modifying pulses includes reducing pulse width. Another exemplary embodiment of modifying pulses includes only delivering full width and amplitude pulses.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims priority to U.S. Provisional Patent Application Ser. No. 60/709,235, filed Aug. 18, 2005, the entire contents of which are specifically incorporated herein by reference. 
     
    
     FIELD  
       [0002]     The presently described system relates generally to the advancement of medical technology, processes, and systems for the treatment of pain, neurological disorders, and other clinical maladies related to neural dysfunction. More specifically, the present disclosure is directed at a system for producing therapeutic lesions or tissue alterations by means of a high frequency generator connected to a patient. In below-described exemplary embodiments, therapeutic energy is delivered in a pulsed rather than continuous manner. Various specific exemplary embodiments of this device accommodate specific exemplary clinical applications and designs.  
       BACKGROUND  
       [0003]     The general use of radiofrequency and high frequency generator systems which deliver electrical output to electrodes that are connected to a patient&#39;s body is known in the clinical literature and art.  
         [0004]     By reference, an example of radiofrequency heat lesioning generators used in clinical practice for the treatment of neural disorders is the Radionics RFG-3C+(Burlington Mass.).  
         [0005]     This device is capable of delivering high frequency energy to patient tissue via an adapted electrode, and associated ground or reference electrode. This device is also capable of delivering low frequency stimulation pulses that are used to accurately localize the electrode placement before treatment.  
         [0006]     Parameters that may be measured by these devices include impedance, HF voltage, HF current, HF power, and electrode tip temperature. Parameters that may be set by the user include time of energy delivery, desired electrode temperature, stimulation frequencies and durations, and level of stimulation output. In general, electrode temperature is a parameter that may be controlled by the regulation of high frequency output power.  
         [0007]     These devices have various user interfaces that allow the selection of one or more of these treatment parameters, as well as various methods to display the parameters mentioned above.  
         [0008]     In a one application of these devices, a patient complains of back pain, or some other pain of nocioceptive or neuropathic origin. A doctor then performs diagnostic blocks with local anesthetic by injecting the anesthetic into the areas that is suspected of generating the pain. If the patient receives temporary pain relief from these injections the doctor concludes that the pain generators were in the location where he made these injections. Unfortunately, the origin of pain is poorly understood; perceived pain at a certain level in the back, for instance, can actually be created from many different and multiple sources.  
         [0009]     Once a location has been identified, the clinician will decide to deliver high frequency energy to this location to permanently destroy the pain generator. A ground or reference plate will be placed on the patient&#39;s thigh to provide a return path for the high frequency energy. An insulated electrode with a small un-insulated tip will he placed at the expected target. Stimulation pulses will be delivered at a sensory frequency (typically 50 Hz), and a stimulation voltage will be placed on the electrode. The clinician is looking for a very low threshold of response from the patient (e.g., less than 0.5 V) to ensure that the electrode is close to the sensory nerves. They will then perform a stimulation test at a muscle motor frequency (e.g., 2 Hz), and increase the stimulation voltage output to 2 v. In this instance, they are looking for no motor response in the patient&#39;s extremities as this would indicate the electrode was too close to the motor nerves. Treatment in this area could cause paralysis. Upon successful completion of these tests, high frequency energy is typically delivered for one or more minutes, while maintaining an electrode tip temperature between 70 and 90 degrees. Alternatively, high frequency energy may be delivered for one or more minutes, but in a pulsed-mode where the high frequency energy is on for a short period of time and off for a long period of time, thus not producing any appreciable heating (reference is made to commonly assigned U.S. Pat. No. 6,161,048, the entire contents of which are specifically incorporated by reference herein).  
       SUMMARY  
       [0010]     The above-described and other disadvantages of the art are overcome and alleviated by the present method and system for taking the energy output from a high frequency generator module and delivering this energy as in a pulsed manner to a treatment electrode. In one exemplary embodiment, a temperature set point is utilized, and the pulses are modified to limit the energy delivered such that the temperature is limited. One exemplary method of modifying pulses includes reducing the amplitude of the pulses. Another exemplary method of modifying pulses includes reducing pulse width. Another exemplary embodiment of modifying pulses includes only delivering full width and amplitude pulses. These exemplary embodiments will be more fully described hereinbelow.  
         [0011]     The above discussed and other features and advantages of the present system will be appreciated and understood by those skilled in the art from the following detailed description and drawings.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]     Referring now to the figures, which are exemplary embodiments and wherein the like elements are numbered alike:  
         [0013]      FIG. 1  represents a simple exemplary embodiment of the presently described system;  
         [0014]      FIG. 2  illustrates an exemplary temperature feedback control mechanism;  
         [0015]      FIG. 3  is another exemplary embodiment showing the representation of the temperature of an electrode in graphical form;  
         [0016]      FIG. 4  is another exemplary embodiment which also illustrates the graphing of the EMG signal;  
         [0017]      FIG. 5  is another exemplary embodiment showing one method of representing pre and post-treatment sensory stimulation thresholds; and  
         [0018]      FIG. 6  is another exemplary embodiment showing three distinct mode selections, as well as an exemplary method to record sensory stimulation thresholds. 
     
    
     DETAILED DESCRIPTION  
       [0019]     Referring to  FIG. 1 , an exemplary embodiment is illustrated. Mode select switch  20  allows the user to selectively connect an electrode  60 , to a high frequency power source. This permits the high frequency power source to selectively be connected to the electrode for the purpose of doing impedance measurements or stimulation threshold testing. The high frequency energy is delivered to the electrode and the electrode temperature is measured and compared to the user set temperature, represented by  40  in  FIG. 1 . In this embodiment the electrode temperature is displayed on a two-dimensional graphics panel identified by  10  in the figure. Also within the graphics display is a representation of temperature vs. time displayed in graphic format. An indicator light, represented by  30  in  FIG. 1 , indicates whether the electrode is active at that particular moment.  
         [0020]     It is very important to note two things from this figure—one is that to the high frequency power source that delivers the high frequency energy and/or low frequency stimulation pulses could be incorporated into this device or could be a separate stand-alone unit, with this device interposed between the high frequency power source and the electrodes. Though the figure shows this device as being AC line connected (that is requiring an electrical outlet for the unit to be plugged into), a battery-operated device would also contemplated.  
         [0021]     It should also be understood that mode selection could be done in many ways and the features of this user interface could be achieved with or without displays, and could use up/ down pushbuttons rather than rotatable selector knobs. For instance, mode select could connect the electrode to the high frequency device, and could also have a position may connect the electrode to an EMG measuring circuit, where the EMG signal may be displayed on a two-dimensional graphics display. An additional position on the mode select would be high frequency energy delivery where either continuous or pulsed high frequency energy may be delivered to the electrode, and a feedback circuit may be incorporated to maintain the electrode tip at a temperature equal to set temp.  
         [0022]     The present disclosure recognizes that where pulsed high frequency is delivered to an electrode, and where a temperature set point is utilized, temperature regulation at the electrode is problematic. The present disclosure recognizes that each pulse delivered should be the same amplitude and pulse width. Three exemplary methods of limiting the energy delivered (and thus, regulating the temperature) are described herein.  
         [0023]     One exemplary method of limiting the energy delivered comprises reducing the amplitude of the pulses. Another exemplary method comprises reducing the pulse width of the pulses. The above methods may be effective to limit the energy delivered even if, as often occurs, the amplitude of the pulses or the pulse shapes vary during treatment and among different patients.  
         [0024]     Another exemplary method comprises delivering only substantially full width and amplitude pulses. In an exemplary implementation of this method, if a temperature set point is reached, no pulses are delivered until the temperature falls below the set point. This is a very uniform method of controlling delivery of pulses. Using this technique, however, results in delivering varying numbers of pulses for a defined treatment time. This method may therefore be further refined by using a treatment scheme wherein pulses are counted (i.e., counting pulses or “doses”) as opposed to defining a time of treatment. In such scheme, treatment is not measured in seconds, but rather in pulses, e.g., 240 pulses or 300 pulses. Using such technique, temperature may be regulated and uniform delivery of treatment is attained.  
         [0025]     With further regard to the instrument illustrated at  FIG. 1 , it should also be noted there are many ergonomic manifestations of this invention and it would be possible to add additional displays, buttons, and/or indicators to allow and/or assist the operator in controlling the device. For instance,  FIG. 1  has an RF on indicator light, represented by  50 , which will indicate whenever high frequency energy is being delivered to the electrode output.  
         [0026]      FIG. 2  is an exemplary logic control diagram indicating a basic exemplary feedback mechanism for the temperature control electrode. HF power, identified as  10 A in the figure, is delivered system. The temperature of the electrode receiving this HF energy, as well as the user set temperature, is measured and a decision point is reached, represented by  20 A in the figure. If the electrode temperature is greater than the user set temperature, the HF power is turned off to the electrode. This action is represented by block  30 A in  FIG. 2 . Then this process starts all over again, where the electrode temperature is once again compared to the user set temperature. Conversely, if the measured temperature for that particular electrode is less than the user set temperature the HF remains on, and again, the electrode temperature is subsequently compared to the user set temperature. In this way temperature feedback is realized, which will maintain the electrode temperature at the same level as the user set temperature.  
         [0027]     In  FIG. 3 , another exemplary embodiment of the user interface is illustrated. As identified by  10 D and  40 D, it is clear that electrode temperature and/or other pertinent parameters need not be displayed on a two-dimensional screen. These could he represented, for instance, by LED or LCD digits.  30 D again represents a two-dimensional graphics display, in this case displaying temperature. Again, a graphics display is not necessary to realize the presently described system and method. To demonstrate exemplary options for user interface, the mode selector has been represented by a series of buttons that are associated with indicator lights identified as  20 D in the figure and Set temp has been identified as up/ down arrows as shown by  50 D. The electrode output has been schematically represented by  60 D.  
         [0028]     In  FIG. 4 , additional exemplary embodiments of the device are shown where, this time, the mode select  20 E, has a position for EMG in addition to a High Frequency energy delivery position. On the two-dimensional display, an EMG signal can be represented, thus identifying electrophysiological activity of a nerve before and/or after the High Frequency treatment. For completeness,  60 E identifies the electrode output, were once again three have been illustrated, although any number greater than 1 is possible with the present system and method. The Set temp user interface has been represented in this diagram as a knob  50 E, though as mentioned earlier there are other contemplated ways to achieve this user interface.  40 E identifies the actual set temperature. IOE is indicating that the temperature displays of the electrodes (—) is not relevant since they would indicate body temperature (37° C.), though this temperature could he displayed if desired.  
         [0029]      FIG. 5  is an exemplary embodiment showing a sensory stimulation graph  30 F, being displayed on the device. In this particular diagram, the electrode has associated with it a thin line and a fat line  35 F indicating pre- and post- stimulation sensory thresholds for the electrode. Again, there are many contemplated ways that these parameters could be represented, and this is just an example of one of many ways in which to achieve a representation of these parameters that are identifiable to the user. The mode select switch, identified as  20 F, has settings for both High Frequency energy and stimulation. The dashes (—), indicated by  10 F in the figure, represent temperature, which is irrelevant in this mode, since with no energy delivery there is no therapeutic heating and the electrode will be reading body temperature (which could of course be displayed). The electrode output, represented by  60 F, once again indicate an electrode connection. Set temp is represented by  5 F in the figure, and its associated value is represented by  40 F in the figure and is depicted as a two digit display.  
         [0030]      FIG. 6  is another exemplary embodiment. Illustrated is a mode select button,  10 G, which allows the user to select between EMG, HF, and stimulate modes. When stimulate or EMG mode is selected, a digit(s) represented by  90 G, indicates whether the electrode is selected. In this embodiment, the user set temperature is identified as a knob indicated by  30 G, and the set temperature value is represented by  80 G in the figure, and is incorporated within a two-dimensional graphics display  20 G. A time vs. temperature graph is indicated by  110 G in the figure, and the electrode temperature, if HF is selected on the mode select, is indicated by  100 G in the figure.  40 G once again indicates an electrode output.  60 G identifies a log button. This button is used in stimulate mode, since the user must identify what stimulation voltage threshold is to be saved for future display.  
         [0031]     While the disclosure has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the disclosure. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the disclosure without departing from the essential scope thereof. Therefore, it is intended that the disclosure not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this disclosure, but that the disclosure will include all embodiments falling within the scope of the appended claims.