Abstract:
A thermostimulation system and method. The inventive thermostimulation system is adapted for use with a console for providing electrical currents for thermal and electrical stimulation in response to a first input from an operator via at least one electrical connector. Generally, the inventive thermostimulation system includes at least one inline control system coupled to the console via electrical connector for regulating the currents to an associated thermostimulation pad via a second connector. The pad has a temperature sensor adapted to provide a feedback signal to the inline control system. In more specific embodiments, plural pads and inline control systems are connected to the console. Each inline control system has a first microprocessor for providing heat and stimulation current control for the pad and a second microprocessor for providing overcurrent safety control for the pad. Each inline control system has a display and a patient over-temperature control switch. Each pad has a connector integrated multilayer construction with a heating element implemented with a wire matrix and slots for flexibility. In addition to a temperature sensor, each pad also includes two electrical stimulation contacts having a wire conductor along the length thereof. Each pad is connected to an associated inline control system via a flat connector. Specially designed strain relief grommets are provided on both ends of the flat cable.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to therapeutic systems. More specifically, the present invention relates to methods and apparatus for providing electrical and thermal stimulation. 
         [0003]    2. Description of the Related Art 
         [0004]    For a variety of therapeutic applications, several treatment modalities are currently known in the art including electrical stimulation, heat therapy and thermostimulation. Electrical stimulation involves the application of an electrical current to a single muscle or a group of muscles. The resulting contraction can produce a variety of effects from strengthening injured muscles and reducing oedema to relieving pain and promoting healing. Many electrical stimulation systems are limited to two to four channels and therefore allow only two to four pads to be applied to a patient. The pads are usually quite small and typically powered with a battery. This results in the application of a small amount of power and a low treatment depth of the resulting electric field. The shallow depth of the electric field generated by conventional electrical stimulation systems limits performance and patient benefit. Some systems have attempted to address this limitation by applying more current, often from a line or main supply source. However, the small size of conventional electrical stimulation pads is such that on the application of larger amounts of power, i.e. the use of higher currents, patients often report the experience of pain or discomfort. 
         [0005]    Heat therapy or thermal stimulation itself is very useful as it has a number of effects such as relaxation of muscle spasm and increased blood flow that promotes healing. However, combination therapy, i.e. the synergistic use of other modalities such as massage, ultrasound and/or electrical stimulation has been found to be more effective than heat therapy alone. 
         [0006]    Thermostimulation is one such combination therapy that involves the use of heat therapy and electrical stimulation simultaneously. With thermostimulation, the healing benefits of heat are provided along with the strengthening, toning, pain relieving and healing benefits of electrical stimulation. Moreover, the application of heat has been found effective in that it allows the patient to tolerate higher currents. This yields higher electric fields strengths, greater depths of penetration and therefore, more positive results than could be achieved with electrical stimulation without heat. 
         [0007]    Unfortunately, there are several problems associated with conventional thermostimulation systems. One problem is due to poor or inadequate pad design. That is, conventional pads are small, hard and die cut with sharp flat edges. The rectangular shape of the pads does not conform to the natural shape of muscle tissue. In addition, conventional pads tend to exhibit a current fall off over the length of the pad. This limits the performance of conventional pads. Further, the connectors are subject to detachment and therefor often fail to comply with government requirements in certain countries. (See for example EN standard 60601-2-35 for medical electrical devices.) 
         [0008]    Further, conventional thermostimulation pads are not waterproof. As a consequence, sweat from the patient combined with the pad gel can cause the stimulation connector and press studs to short directly to the patient, which can result in the patient being shocked or burned. 
         [0009]    Moreover, conventional thermostimulation pads are generally inflexible and yield to breakage of the heating element if bent or folded too frequently. More significantly, conventional thermostimulation pads are not designed to detect, measure and/or monitor temperature of the pad when on the patient. Consequently, effective temperature regulation is not provided with conventional thermostimulation systems. 
         [0010]    Hence, a need remains in the art for an improved system or method for thermostimulation therapy that is more safe and effective. 
       SUMMARY OF THE INVENTION 
       [0011]    The need in the art is addressed by the thermostimulation system and method of the present invention. The inventive thermostimulation system is adapted for use with a console for providing electrical currents for thermal and electrical stimulation in response to a first input from an operator via at least one electrical connector. Generally, the inventive thermostimulation system includes at least one inline control system coupled to the console for regulating the currents to an associated thermostimulation pad. The pad has a temperature sensor adapted to provide a feedback signal to the inline control system. 
         [0012]    In more specific embodiments, plural pads and inline control systems are connected to the console. Each inline control system has a first microprocessor for providing heat and stimulation current control for the pad and a second microprocessor for providing over-temperature control for the pad. Each inline control system has a display and a button to allow confirmation of temperatures of more than 38 degrees Celsius. Each pad has a connector integrated multilayer construction with a heating element implemented with a wire matrix and slots for flexibility. In addition to a temperature sensor, each pad also includes two electrical stimulation contacts having a wire conductor along the length thereof. Each pad is connected to an associated inline control system via a flat cable. Specially designed strain relief grommets are provided on both ends of the flat cable where they terminate with the pad or inline control system. 
         [0013]    The inventive thermostimulation method includes the steps of applying a thermostimulation pad with connector integrated multilayer construction to a patient having a temperature sensor adapted to feedback a temperature signal; coupling the pad to a console via an inline control system; setting the console to generate predetermined electrical currents to the inline control system for thermal and electrical stimulation via a first connector; and regulating the temperature of the pad via the inline control system in response to the predetermined electrical current for thermal stimulation and the feedback temperature signal. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1  is a perspective view of a typical thermostimulation system implemented in accordance with conventional teachings. 
           [0015]      FIG. 2  is a simplified block diagram of a typical thermostimulation electrical system provided within the console of  FIG. 1 . 
           [0016]      FIGS. 3   a - 3   c  illustrate the typical conventional thermostimulation pad of  FIGS. 1 and 2  in more detail.  FIG. 3   a  is a top view of the pad,  FIG. 3   b  is a sectional side view taken along the line  3   b - 3   b  of  FIG. 3   a , and  FIG. 3   c  is a bottom view of the pad. 
           [0017]      FIG. 4  is a simplified perspective view of a thermostimulation system implemented in accordance with an illustrative embodiment of the present teachings. 
           [0018]      FIG. 5  shows a perspective bottom view of the pad of  FIG. 4 . 
           [0019]      FIG. 6  is an exploded upside down view of a portion of the pad of  FIG. 4  in disassembled relation. 
           [0020]      FIG. 6   a  is a top plan view of the heating element of the illustrative embodiment of the pad of  FIG. 4 . 
           [0021]      FIG. 6   b  is a magnified view of a portion of the heating element of  FIG. 6   a.    
           [0022]      FIGS. 6   c - g  show the grommet used in the pad of  FIG. 4 . 
           [0023]      FIG. 6   c  shows an upper section of the illustrative implementation of the grommet. 
           [0024]      FIG. 6   d  shows a lower section of the illustrative implementation of the grommet. 
           [0025]      FIG. 6   e  is a top view of the grommet. 
           [0026]      FIG. 6   f  is a side view of the grommet. 
           [0027]      FIG. 6   g  is a perspective view of the upper section of the grommet. 
           [0028]      FIG. 7  is a perspective side view of the inline control system of  FIG. 4  fully assembled. 
           [0029]      FIG. 8  is a perspective side view of the inline control system of  FIG. 7  disassembled. 
           [0030]      FIG. 9  is a sectional side view of the inline control system of  FIG. 4  fully assembled. 
           [0031]      FIG. 10  below is an electrical block diagram of the inventive system including the control system elements. 
           [0032]      FIGS. 11   a - c  are flow diagrams of the firmware in accordance with an illustrative embodiment of the present teachings. 
           [0033]      FIG. 11   a  is a flow diagram of the firmware executed by the main microcontroller of  FIG. 10 . 
           [0034]      FIG. 11   b  is a flow diagram of the firmware executed by the safety microcontroller of  FIG. 10 . 
           [0035]      FIG. 11   c  is a flow diagram of the firmware executed by the main and safety microcontrollers of  FIG. 10  for a self-test mode of operation. 
       
    
    
     DESCRIPTION OF THE INVENTION 
       [0036]    Illustrative embodiments and exemplary applications will now be described with reference to the accompanying drawings to disclose the advantageous teachings of the present invention. 
         [0037]    While the present invention is described herein with reference to illustrative embodiments for particular applications, it should be understood that the invention is not limited thereto. Those having ordinary skill in the art and access to the teachings provided herein will recognize additional modifications, applications, and embodiments within the scope thereof and additional fields in which the present invention would be of significant utility. 
       Conventional Thermostimulation System 
       [0038]      FIG. 1  is a perspective view of a typical thermostimulation system implemented in accordance with conventional teachings. The system  10 ′ includes a conventional thermostimulation console  20 ′ and a plurality of thermostimulation pads  30 ′. The console may be purchased from Ross Estetica of Barcelona Spain. (See http://corporativa.ross.es/rosseng/ross/indexross.htm.) 
         [0039]      FIG. 2  is a simplified block diagram of a typical thermostimulation electrical system provided within the console of  FIG. 1 . The system  10 ′ includes a power supply  22 ′ disposed in the console  20 ′ that provides current for the pads  30 ′ through a set of attenuators  24 ′ and  26 ′ for each pad  30 ′. The first attenuator  24 ′ regulates current to a set of stimulation contacts  32  and  34  provided on an exposed surface of the pad  30 ′ and the second attenuator  26 ′ regulates current to a heating coil  36 ′ embedded within the pad. A pad select switch  28 ′ provides an enable signal for each attenuator under operator control and outputs the setting level status to the operator via a display  29 ′. Note that the system  10 ′ only sets the heat and stimulation current levels. As no temperature sensor is provided in the conventional pad  30 ′, no pad temperature regulation or control is possible. 
         [0040]    In addition, it should also be noted that the electrical arrangement of  FIG. 2  is provided for illustration only. Other electrical arrangements may be known and used in the art. 
         [0041]      FIGS. 3   a - 3   c  illustrate the typical conventional thermostimulation pad  30 ′ of  FIGS. 1 and 2  in more detail.  FIG. 3   a  is a top view of the pad,  FIG. 3   b  is a sectional side view taken along the line b-b of  FIG. 3   a , and  FIG. 3   c  is a bottom view of the pad. The conventional pads  30 ′ are fabricated of silicone sheets glued together to encapsulate a foil heater with a separate wire for an electrostimulation pad. The pads are die cut from rolled sheets of silicone and therefore typically have sharp edges that are often uncomfortable to the patient. The upper surface is translucent and the bottom surface is gray silicone. 
         [0042]    As best illustrated in the side view of  FIG. 3   b , the conventional pad  30 ′ includes the first and second electrically conductive strips  32 ′ and 34′ for electrostimulation. Shown more clearly in the bottom view of  FIG. 3   c , the strips  32 ′ and 34′ are fabricated of carbon loaded silicone (i.e., polymerized siloxane or polysiloxane) or other suitable material. Returning to  FIG. 3   b , the conductive strips  32 ′ and  34 ′ are secured to a pad body  38 ′ by a layer or pad of glue  35 ′. 
         [0043]    Typically, the pad body  38 ′ is also fabricated of silicone. A second layer of silicone  39 ′ is provided on the pad body  38 ′ for structural support. The upper surface of the second layer  39 ′ is typically treated with a primer (not shown) and the heating element  36 ′ is mounted between the primed second layer  39 ′ and a primed third layer of silicone  42 ′. The heating element  36 ′ is typically a coil fabricated with aluminum foil. 
         [0044]    Stimulation current is provided via wires  70 ′ attached to the conductive strips  32 ′ and  34 ′ by first and second press stud type connectors  44 ′ and  46 ′. Though not shown in  FIG. 3   b , the connectors  44 ′ and  46 ′ extend through the third, second and first structural layers  42 ′,  39 ′ and  38 ′ sequentially to connect with the electrical stimulation strips  32 ′ and  34 ′. Silicone covers  48 ′ and  49 ′ extend around the upper end of the connectors  44 ′ and  46 ′ respectively to protect the patient from electrical burns. In  FIG. 3   b , the cover  48 ′ is shown depressed to expose the connector  44 ′ to illustrate that a wire from the console  20 ′ may be clipped thereto. 
         [0045]    A second set of connectors  52 ′ and  54 ′ extend through the third layer  42 ′ to the heating coil  36 ′ and provide electrical connectivity thereto. Silicone covers  56 ′ and  58 ′ are provided for the second set of connectors  52 ′ and  54 ′ respectively. 
         [0046]    As noted above, there are several shortcomings associated with the conventional pad design set forth above. That is, conventional pads are hard and die cut with sharp flat edges. The rectangular shape of the pads does not conform to the natural shape of muscle tissue. In addition, conventional pads tend to exhibit a current fall off over the length of the pad. This limits the performance of conventional pads. Further, the connectors are subject to detachment and therefor often fail to comply with government requirements in certain countries i.e., EN standard 60601-2-35 for medical electrical devices. In addition, conventional thermostimulation pads are not waterproof and have recesses into which materials can be deposited which are difficult to clean and could carry risk of infection from patient to patient. As a consequence, sweat from the patient combined with the pad gel can cause the stimulation connector and press studs to short directly to the patient, which can result in the patient being shocked or burned. Moreover, conventional thermostimulation pads are too hard and, being too inflexible, yield to frequent bending and breakage of the coil disposed therein. More significantly, conventional thermostimulation pads are not designed to detect, measure and/or monitor temperature. Hence, a need remains in the art for an improved system or method for thermostimulation therapy that is more safe and effective. As discussed more fully below, the inventive pads address this need in the art. 
       Inventive System 
       [0047]    Overall System 
         [0048]      FIG. 4  is a simplified perspective view of a thermostimulation system implemented in accordance with an illustrative embodiment of the present teachings. As shown in  FIG. 4 , the system  10  includes a conventional thermostimulation console  20 ′ with, in accordance with the present teachings, a plurality of novel thermostimulation pad assemblies  30  electrically coupled thereto. Each pad assembly  30  includes a novel inline control system  40  and an associated multilayer injection molded dual function (heat and stimulation) pad  50  of unique design and construction with integrated sensor in accordance with the present teachings. Each control system  40  is connected to an associated pad  50  via a cable  60 . As discussed more fully below, in the best mode, the cable  60  is flat. 
         [0049]    Pads 
         [0050]      FIG. 5  shows a perspective bottom view of the pad  50  of  FIG. 4 .  FIG. 6  is an exploded upside down view of a portion of the pad  50  of  FIG. 4  in disassembled relation. As shown in  FIGS. 5 and 6 , the pad  50  includes first and second elongate substantially parallel conductive strips  552  and  554 . In the illustrative embodiment, each conductive strip has a Shore hardness of 50 A—i.e. medical grade (USB Class 6) ten percent (10%) carbon loaded silicone. For example, Wacker LR 3162 could be used. This product has an electrical resistance of 1 kΩ per cm. In the illustrative embodiment, the strips are 51.5 millimeters (mm) wide, 521 mm in length and 1.85 mm thick. Those of ordinary skill in the art will appreciate that the present teachings are not limited to the dimensions of the illustrative embodiment. 
         [0051]    A polymer connector  556  is coupled to one end of the first and second strips  552  and  554  and serves as an end piece therefor and the second end of each strip is free. In the illustrative embodiment, the connector  556  is fabricated of Shore 40 A silicone and serves as an insulator and support for wires  558  and  559  that provide a connection to the strips  552  and  554  respectively. In practice, one of the strips is powered a positive contact and the other provides a negative contact. 
         [0052]    The two strips  552  and  554  are molded and then the end piece  556  is molded separately. These pieces are glued together and placed back into a mold and the next layer  560  is over-molded over the assembly to provide a single molded piece consisting of the strips  552 ,  554 , end piece  556 , and layer  560 . In the preferred embodiment, the over-layer  560  is made of medical grade Shore 40 A polymer or other material suitable for a particular application. Note the grooves  553  and  555  and recess  557  within the over-layer adapted to receive and seat the strips  552  and  554  and the end piece  556  respectively. The wires  558  and  559  are then laid into the slots running through the overmould layer and into the grooves in the stimulation strips  552  and  554 . The wires are then glued in place using a carbon loaded RTV (room temperature vulcanized) silicone glue. This allows for the electrical current to be passed from the wires  558  and  559  to the stimulation strips  552  and  554 . Once cured, the remaining space in the slot in the  560  overmould layer is filled with non-conductive RTV silicone glue up to the same level of the surface of the overmould layer  560 . 
         [0053]    As shown in  FIG. 6 , a heating element  570  is provided over the layer  560 . In the best mode, the heating element  570  is implemented as a built in wire matrix and is held in place with a layer of silicone  580 . First and second temperature sensors  572  and  574  are mounted in the heating element  570 , one is a live sensor measuring temperature and feeding this information back to the control box and the second is a back up should the first sensor fail. In the illustrative embodiment, each temperature sensor is implemented as a conventional 1 kilo-ohm RTD (resistive temperature detector). In the illustrative embodiment, the heating element is a wire matrix bonded in silicone with a thickness of 0.75 mm, over the majority of the surface apart from where the RTDs are mounted, and is rated at 400 watts per square meter using 24 volts alternating current. Note the provision of slots  576  in the heating element  570 . These slots serve to improve flexibility in all planes of the element. 
         [0054]    In the illustrative embodiment, as illustrated in the top plan view of  FIG. 6   a  and the magnified view of  FIG. 6   b , the extension  578  of the heating element  570  has a number of solder connections to facilitate electrical connection of the heating element  570  to the cable  60 . The extension tab  578  is adapted to be received within a strain relief grommet  582  in the heater over-layer  580  along with the extensions  562  of the end piece  556  and  564  of the layer  560 . In the illustrative embodiment, the grommet does not come into contact with the extension  578 . The grommet  582  receives the flat cable  60  which is then stripped back and the associated wires are connected to the various solder pads on the extension  578 .  FIG. 6   c  shows the upper section  584  of the illustrative implementation of the grommet  582 .  FIG. 6   d  shows the lower section  586  of the illustrative implementation of the grommet  582 .  FIG. 6   e  is a top view of the grommet,  FIG. 6   f  is a side view of the grommet and  FIG. 6   g  is a perspective view of the upper section of the grommet  582 . In the preferred embodiment, the grommet  582  is made of TPU (thermoplastic polyurethane) and is implemented in two halves, an upper section  584  and a lower section  586 . The upper and lower sections  584  and  586  are glued together and these sections are glued to the flat cable  60 . In the best mode, the upper and lower sections  584  and  586  of the grommet  582  are glued together and to the cable  60  with cyanoacrylate glue. 
         [0055]    Those skilled in the art will appreciate that the present invention is not limited to the materials utilized in the fabrication of the illustrative embodiment. Other materials may be used without departing from the scope of the present teachings. 
         [0056]    In the illustrative embodiment, the heater over-layer  580  is Shore 40 A medical grade silicone in construction. Nonetheless, as noted above, it should be noted that the present invention is not limited to any particular material or hardness. 
         [0057]    Each pad is assembled from the stimulation side. In the best mode, the structure of the pad  50  is based on a multi-step injection molding process, with over-molding of the various layers to build up the base of the pad to the complete pad thickness and embed and encapsulate the various components within it, such as the electrostimulation wires and heating element. The final step is to insert and bond the top lid of the pad into the assembled structure. The steps of the injection molding process include moulding of the stimulation strips, over moulding of the stimulation strips to encapsulate the stimulation wires to create the patient facing surface of the pad and the moulding of the lid of the pad  580  which encapsulates the heating element and creates the upper facing surface of the pad and seals in the flat cable and grommet. 
         [0058]    Hence, in accordance with the present teachings, the strips  552  and  554  and the layers  560 ,  570  and  580  and the grommet  582  are molded into a single unitary multilayer injection molded dual function (heat and electrostimulation) construction. 
         [0059]    Flat Cables 
         [0060]    Returning to  FIG. 4 , a novel flat cable  60  connects each pad to its associated inline control and a conventional cable  70  is used to connect each inline control system to the console  20 . The flat cables  60  enhance patient comfort. In the illustrative embodiment, the flat cable  60  linking the control system  40  to the pad  50  is approximately 2.5 meters long and 17.38 mm wide. The cable  60  has inner core of 14 insulated wires, with an outer protective sheath in a white polyvinyl chloride (PVC). Flat cables are commercially available from manufacturers such as Spectra Strip of Hampshire, Great Britain. 
         [0061]    Inline Control System 
         [0062]      FIG. 7  is a perspective side view of the inline control system  40  of  FIG. 4  fully assembled. 
         [0063]      FIG. 8  is a perspective side view of the inline control system  40  of  FIG. 7  disassembled. As shown in  FIG. 8 , the control system  40  includes a two part injected molded ABS plastic housing  410  with an upper casing  412  and a lower casing  414 . The housing  410  is adapted to retain a multilayer printed circuit board  418  on which an integrated circuit  420  is disposed. A microprocessor (not shown) is provided by the integrated circuit  420 . Numerous additional electrical components are mounted onto the printed circuit board  418  along with a liquid crystal display (LCD)  422 . 
         [0064]    As shown in  FIG. 8 , a small Perspex window  430  protects the LCD  422 . In the best mode, the LCD display  422  shows both the target and actual temperatures for the associated pad. The window  430  seats within an aperture  426  in the upper casing  412  of the housing  410 . A plate  430  contoured to fit within a depression on the upper surface of the upper casing  412  is fitted with a manual override switch  432 . The switch  432  connects to the control circuitry on the printed circuit board  418  via a flexible wire  434  and pins  436 . 
         [0065]    In the illustrative embodiment, a switch is used to enable the user to confirm when a user wants to heat a pad  50  above 38 degrees Celsius. The round cable  70  coming from the console  20  enters the top of the control system  40  and is held in place by a second grommet  438 . The flat cable  60  enters the system  40  from the bottom and is held in place by a third grommet  440  that is also used as a strain relief device at the cable termination with the pad. In the illustrative embodiment, this grommet is a standard, over-the-counter cable retention fixator. As discussed more fully below, the third grommet  440  is a two section grommet which captures the flat cable as it enters the system  40 . The system  40  is then held together by four screws  416 . As illustrated in the sectional side view of  FIG. 9 , when secured together, the upper and lower casings  412  and  414  provide first and second chambers for seating the second grommet  438  and the third grommet  440 . 
         [0066]    Electronics 
         [0067]    As mentioned above, each pad has a heating element, two RTD sensors (one for active temperature control and another for backup) and two stimulation pads that make electrical contact with the user. 
         [0068]      FIG. 10  is an electrical block diagram of the inventive system  10  including the control system elements  40 . The circuitry of the control system  40  is powered by the heating current from the console  20 . The control system  40  provides intelligent operation for the pad  50 , monitoring the current going to both electrostimulation pads  552  and  554  and the heating element  570 . These currents can be set at different levels by the control system  40  depending on the program selected or manually adjusted after a program is selected. The conventional console  20  does not allow for the temperature to be measured or monitored but instead typically has a heating current level setting described as a “heating percentage”. Since a regulation or control functionality is not conventionally available, the current sent to the pads could allow them to heat to more than 42 degrees Celsius, a level which is outside of safe levels and the requirements set by the EN60601-2-35 standard. 
         [0069]    As illustrated in  FIG. 10 , in the illustrative embodiment, each control system  40  is implemented with first and second microcontrollers (implemented in the best mode with microprocessors)  404  and  402 , that control and interrupt the current to the stimulation electrodes  552  and  554  and the heating element  570  of  FIG. 6  respectively. The first controller  404  serves as a main controller and the second controller  402  serves as a safety controller. As discussed more fully below, each microcontroller runs unique software (i.e. firmware) stored on a tangible medium, such as an electrically erasable programmable read only memory (EPROM), in the integrated circuit  420  of  FIG. 8 . 
         [0070]    Software 
         [0071]      FIGS. 11   a - c  are flow diagrams of the firmware executed by the microprocessors in accordance with an illustrative embodiment of the present teachings.  FIG. 11   a  is a flow diagram of the firmware executed by the main microcontroller  402  of  FIG. 10 .  FIG. 11   b  is a flow diagram of the firmware executed by the safety microcontroller  402  of  FIG. 10 .  FIG. 11   c  is a flow diagram of the firmware executed by the main and safety microcontrollers of  FIG. 10  for a self-test mode of operation. Both microcontrollers monitor the heating power control devices to determine whether they perform the correct on-off switching action or have failed as a short circuit or an open circuit. During the power up stage, the MMC and SMC communicate using an asynchronous communications link. In the illustrative embodiment, the microprocessors communicate with each other every second to pass status information using an I2C serial interface. 
         [0072]    The MMC  404  sends messages to the SMC to tell it which test is being performed and then the SMC  402  sends the results of the tests at each stage. Only if all the stages pass with no failures is power applied to the heating circuit  570  in the pad. 
         [0073]    During power up ( 602 ), or at a power setting greater than five percent (5%) of maximum, the main microcontroller (MMC)  404  performs a self-test ( 604 ) to detect any possible failures and then communicates with the safety microcontroller (SMC)  402 . As illustrated in  FIG. 11   c , the self-tests are synchronised such that all hardware functionality is tested before enabling heating power to the patient. 
         [0074]    The pad assembly, including the electronics, is calibrated. Calibration information is stored in an EPROM (not shown) within the MMC  404 . In order that the SMC  402  can accurately determine whether the associated regulated pad is overheating, a calibrated maximum temperature value is passed from the MMC to the SMC during the power up procedure. 
         [0075]    After checking for faults ( 606 ) the MMC  404  enables stimulation ( 608 ) and monitors the percentage power setting of the console  20  (see steps  614 - 616 ). This is used to set a target temperature for the pad. This target temperature is displayed on the LCD  422 . Should the target temperature be greater than 38° C. the software  600  requires the operator to press the front panel switch on the console  20  to confirm the intention to set a higher temperature. Table I below lists illustrative target temperatures corresponding to various power levels. 
         [0000]                                TABLE I                       Power setting %   Target Temperature                            5-20   36           20-30   37           30-40   38           40-50   39           50-60   40            60-100   41                        
In the illustrative embodiment, a reduction in target temperature would not have to be confirmed.
 
         [0076]    During the pre-heating stage of a procedure the CTEMS unit demand 100% heat for three minutes. This is to heat up the pads prior to placement on a patient. This is interpreted as a demand for 41° C. and if this temperature is not confirmed by the operator the unit will heat up to the safety temperature of 38° C. 
         [0077]    The MMC controls the temperature using a PID control loop. The actual temperature is measured using the temperature sensor  572  embedded in the pad. The SMC monitors the pad temperature using the other temperature sensor  574 . 
         [0078]    There is a two colour LED in the front facing section of the connection box. This will flash red and green and is used to provide status information. 
         [0000]    
       
         
               
               
               
             
           
               
                   
                 TABLE II 
               
               
                   
                   
               
               
                   
                 LED 
                 Information 
               
               
                   
                   
               
             
             
               
                   
                 Green flashing 
                 Heating up to target 
               
               
                   
                 Green continuous 
                 Target reached 
               
               
                   
                 Red flashing 
                 Over temperature, when actual is above 
               
               
                   
                   
                 target but not above 42° C. 
               
               
                   
                 Red continuous 
                 Fault, heating and stimulation disabled. This 
               
               
                   
                   
                 could be temperature above 42° C. or a 
               
               
                   
                   
                 hardware fault. 
               
               
                   
                   
               
             
          
         
       
     
         [0079]    As shown in  FIG. 11   b , after performing self-tests ( 634 ) the SMC  402  measures the safety temperature via the second sensor  574  and disables the associated pad  50  if the specified maximum temperature is reached or exceeded. 
         [0080]    Operation 
         [0081]    The following describes the method of operation of the inventive system  10  in accordance with an illustrative implementation thereof: 
         [0082]    1. First, the operator plugs the pad cord  70  into the front of the console  20 . 
         [0083]    2. Next, the operator selects the desired program and starts the preheating phase. The display will flash at 41° C. and then heat up to 38° C. unless the override button  432  ( FIG. 8 ) is pressed at which stage it would heat to 41° C. The preheating phase lasts for 3 minutes (and can be repeated). 
         [0084]    3. Once the preheating is complete, the user presses “pause” on the system itself and the LCD display on the connection box will go blank. 
         [0085]    4. The patient is laid on the bed and the pads are strapped to the patient in the desired configuration. 
         [0086]    5. The operator then presses pause again and the program starts. The LCD  422  will then show the actual and target temperature again and the user will have to press the membrane button on each pad if the system program has a current % of 40% or above to allow the pad to heat to above 38° C. 
         [0087]    6. The pad control system  40  will then monitor the temperature and ensure that it does not go above the desired level. 
         [0088]    7. If the LED goes continually red for a period of more than a couple of minutes pad control system  40  will interrupt all the currents (both electrical stimulation and heat) to the pad and the operator will put the system on pause and replace the pad. 
         [0089]    Thus, the present invention has been described herein with reference to a particular embodiment for a particular application. Those having ordinary skill in the art and access to the present teachings will recognize additional modifications, applications and embodiments within the scope thereof. 
         [0090]    It is therefore intended by the appended claims to cover any and all such applications, modifications and embodiments within the scope of the present invention. 
         [0091]    Accordingly,