Abstract:
A method and apparatus for providing concurrent applications of intermittent pneumatic compression therapy and vacuum assisted closure therapy generally comprises a wound dressing for introduction of a negative pressure into a wound on a patient&#39;s foot and a foot wrap for application of positive, compressive forces to substantially all of the patients foot. A suction pump, having an associated vacuum sensor and first feedback mechanism, supplies negative pressure to the wound dressing. A ventable source of pressurized gas, having an associated pressure transducer and second feedback mechanism, supplies positive force to the foot wrap. At least one control system is operably associated with the suction pump and ventable source of pressurized gas for controlling the negative and positive applications of pressure to the patient&#39;s foot. Controlled modes for operation include continuous or intermittent application of one or both therapies and simultaneous or cycled application of the therapies.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
   This is a continuing application, under 35 U.S.C. § 120, of U.S. application Ser. No. 09/458,280, filed Dec. 10, 1999, now U.S. Pat. No. 7,214,202 which is a divisional application of U.S. application ser. No. 08/903,026, filed Jul, 30, 1997, now U.S Pat. No. 6,135,116 which claims the benefit of U.S. application Ser. No. 60/053,902, filed Jul. 28, 1997; the prior applications are herewith incorporated by reference in their entirety. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to methods and apparatus for treating foot ulcers. More particularly, the invention relates to methods and apparatus for applying positive and/or negative pressures to treat foot ulcers such as diabetic ulcers, arterial ulcers, venous stasis ulcers, pressure ulcers, and the like. 
   2. Description of the Related Art 
   Foot ulcers can be devastating—they are difficult to heal and are potentially limb-threatening. One of the difficulties is that a patient will often lose sensation in the area of an ulcer and, as a result, the patient tends to abuse the ulcer without notice. Foot ulcers, in particular, are troublesome because they are out of the patient&#39;s sight, especially when located on or near the patient&#39;s heel. Unseen and unfelt, the patient does not realize that the foot ulcer is colliding into a wheelchair, bedpost or the like. Consequently, the onset of a foot ulcer may place the foot at a significant risk for progression toward sepsis, gangrene and, ultimately, amputation. 
   Current treatment options for foot ulcers are varied, but all tend to be costly and traumatic; greater efficacy is thus desired. One of the most common treatment options is debridement of necrotic tissue followed by an attempt to physically close the ulcer, typically with sutures, skin grafts or the like. Unfortunately, many patients do not respond quickly, or at all, to such traditional treatment and the patient&#39;s condition often worsens. The resulting economic and emotional costs to the patient, and the patient&#39;s family, are staggering. 
   On the positive side, there have long been techniques available for promoting healthy circulation of body fluids. The concept of applying positive and/or negative pressure to help affect circulation is ancient, and many have sought to apply this concept to the foot in the form of inflatable boots that squeeze the foot and/or leg. Some have applied alternating positive and negative pressures, in a cyclic fashion, to first force blood out of the foot with positive pressure and then draw blood back into the foot with negative pressure. Recent products offered by Applicant under the trade designation “PLEXIPULSE” have provided intermittent compression, for a variety of indications, through pneumatic force externally applied to the foot. Such products are used, for example, to help prevent venous stasis and to promote circulation or to help treat and assist healing of cutaneous ulceration. 
   Another approach, for treatment of wounds, is represented by Applicant&#39;s products recently made commercially available under the trade designations “V.A.C.” or “VACUUM ASSISTED CLOSURE.” The “V.A.C.” products generally comprise the application of negative pressure directly to a wound site, either on a continuous or intermittent basis. Such therapy units direct negative pressure to the wound site through a disposable pad, which includes a wound dressing and associated tubing, filters and drainage receptacles. The dressing itself includes a porous foam dressing sized to fit within the wound, the tubing directs the negative pressure into the foam, and the combination is sealed into the wound with the use of an adhesive drape that overlaps the entire wound site as well as a margin of surrounding intact skin. This therapy is promising for treatment of pressure ulcers and chronic open wounds, including decubitus ulcers and diabetic ulcers. 
   Both of the above-described therapies are currently available as of the filing date of this present application; despite the availability of such progressive therapies, however, foot ulcers continue to present serious concerns for patients and caregivers. It is therefore a fundamental object of the present invention to advance upon the prior art by providing an improved method and apparatus for effecting intermittent pneumatic compression concurrently with vacuum assisted closure. Many additional problems, obstacles and challenges present in existing modalities for the treatment of foot ulcers will be evident to caregivers and others of experience and ordinary skill in the art. 
   SUMMARY OF THE INVENTION 
   In accordance with the foregoing objects, the present invention—an improved method and apparatus for providing concurrent applications of intermittent pneumatic compression and vacuum assisted closure—generally comprises a wound dressing for introduction of a negative pressure into a wound on a patient&#39;s foot and a foot wrap for application of positive, compressive forces to substantially all of the patients foot. A suction pump, having an associated vacuum sensor and first feedback mechanism, supplies negative pressure to the wound dressing. A ventable source of pressurized gas, having an associated pressure transducer and second feedback mechanism, supplies positive force to the foot wrap. At least one control system is operably associated with the suction pump and ventable source of pressurized gas for controlling the negative and positive applications of pressure to the patient&#39;s foot. 
   In preparation for operation, the wound dressing is preferably first applied to the patient&#39;s foot followed by application of the foot wrap. Each is then in turn operably connected to its respective pressure source. Specifically, for application of the wound dressing, a porous pad, having plastic tubing inserted therein for connection to the suction pump, is inserted at least partially into the wound on a patient&#39;s foot. The wound dressing, and margin of impact surrounding the wound, is then preferably covered with a wound drape. The foot wrap, having fluid connection hardware associated therewith, is then placed in operable position over the wound dressing. Finally, the pad&#39;s plastic tubing is placed in fluid communication with the suction pump and the foot wrap&#39;s connection hardware is placed in fluid communication with the ventable source of pressurized gas. 
   In operation, negative pressure to the wound dressing is monitored and adjusted as necessary, by an integrated control system, to achieve desired therapy. Similarly, the positive, compressive force delivered to substantially the entire foot through the foot wrap is monitored and adjusted as necessary, also by an integrated control system, to achieve the desired therapy. Also effected by the integrated control system, the application timing of each component therapy is adjustable to allow concurrent application of pneumatic compression therapy and vacuum assisted closure therapy. It is to be understood that such concurrent therapy may entail continuous or intermittent application of one or both therapies and may or may not involve simultaneous application of the therapies. 
   Finally, many other features, objects and advantages of the present invention will be apparent to those of ordinary skill in the relevant arts, especially in light of the foregoing discussions and the following drawings, exemplary detailed description and appended claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Although the scope of the present invention is much broader than any particular embodiment, a detailed description of the preferred embodiments follows together with illustrative figures, wherein like reference numerals refer to like components, and wherein: 
       FIG. 1  illustrates, for reference purposes, regions  101 - 106  of a typical foot  100 ; 
       FIG. 2  shows, in a schematic block diagram, a first configuration  200  of the preferred embodiment of the present invention; 
       FIG. 3  shows, in perspective view, exemplary foot compression wraps  301 ,  302  as are utilized in the implementation of the preferred embodiment of the present invention; 
       FIG. 4  shows, in semi-perspective view, an exemplary wound closure dressing  402  and fluid reservoir  401  as are utilized in the implementation of the preferred embodiment of the present invention; 
       FIG. 5  shows, in a schematic block diagram, a second configuration  500  of the preferred embodiment of the present invention; 
       FIGS. 6A and 6B  illustrate, in plan view, application, as taught for implementation of the preferred embodiment of the present invention, of a wound closure dressing  402 ,  404  to a human foot  100 ; 
       FIGS. 7A-7D  illustrate, in perspective view, application, as taught for implementation of the preferred embodiment of the present invention, of a foot compression wrap  301 ,  302  to a human foot  100 ; and 
       FIG. 8  shows a wound closure dressing  404  and foot compression wrap  301  as simultaneously applied to a human foot  100  in implementation of the preferred embodiment of the present invention. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   By this reference, the full disclosures of Applicant&#39;s U.S. patent application Ser. No. 08/039,574 filed Mar. 23, 1993 and U.S. patent application Ser. No. 08/517,901 filed Aug. 22, 1995, are each incorporated herein as though set forth in their respective entireties. Copies of each of these applications are submitted herewith, through an accompanying Information Disclosure Statement, for entry into this application&#39;s file wrapper. 
   Although those of ordinary skill in the art will readily recognize many alternative embodiments, especially in light of the illustrations provided herein, this detailed description is exemplary of the preferred embodiments of the present invention, the scope of which is limited only by the claims appended hereto. 
   For reference purposes, various regions  101 - 106  of a typical foot  100  are shown in  FIG. 1 . Region  101  is referred to as the ankle region. Region  102  is referred to as the heel region. Region  103  is referred to as the plantar arch region. Region  104  is referred to as the metatarsal head, or ball, region. Region  105  is referred to as the toe region. Region  106  is referred to as part of the dorsal aspect region. Although these regions are shown as being mutually exclusive, this representation is for purposes of illustration only. It should be understood that one region may overlap another. For example, reference to the heel region  102  is not necessarily confined to that region illustrated in the drawings; the reference may actually include the heel region  102  and overlapping portions of adjacent regions such as the ankle region  101  or plantar arch region  103 . The same may be true of references to the metatarsal head  104 , or other, regions. Ulcers may occur either centrally or on either side of the foot  100  in any of the regions  101 - 106  shown; however, clinical evidence has shown that ulcers are most prevalent in the heel region  102  and the forefoot beneath the metatarsal head region  104 . A representative location  1   10  of an ulcer is designated with a dashed margin in  FIG. 1 , at the bottom of the heel region  102 . 
     FIG. 8  illustrates a typical preferred application of the present invention for treating and ulcer, or other wound, at ulcer location  110 . Using the various apparatus and methods described further herein, localized negative pressure is induced on a foot  100  at the ulcer location  110  while positive, compressive force is applied to the foot  100 . The resulting combination actively stimulates healing at the ulcer site  110  while also promoting healthy circulation of blood and nutrients. 
   Referring to  FIGS. 2-4 , there is shown a first configuration  200  of a system for therapeutic treatment of foot ulcers such as that shown at the ulcer location  110 . This first configuration generally comprises an efficient combination of previously available vacuum assisted closure and intermittent pneumatic compression technologies for concurrent application of positive and negative pressures to an affected foot. According to the first configuration  200  of the preferred embodiment, there is generally provided an intermittent pneumatic compression unit  201  and a vacuum assisted closure unit  202  in operable communication with a single embedded micro-controller unit  203 . The micro-controller unit  203  may be implemented in any of a variety of hardware and/or software designs as will be apparent to those of ordinary skill in the relevant arts. As will be apparent herein, the micro-controller unit  203  provides a single point of feedback driven control for both the intermittent pneumatic compression unit  201  and the vacuum assisted closure unit  202 . 
   The intermittent pneumatic compression unit  201  of the first-configuration  200  generally comprises an oscillating air compressor  204  in fluid communication with an air reservoir  205  through a one-way check valve  206 . As will be understood further herein, the check valve  206  serves to prevent pneumatic back flow from the air reservoir  205  to the oscillating air compressor  204  during periods in which the air compressor  204  is not in operation. The air reservoir  205  of the preferred embodiment is in fluid and operable communication with one or more foot compression wraps  301 ,  302  through a series of three-way solenoid valves  207 - 209 , ports  210 ,  211 , connectors  303 ,  304  and plastic, or other suitable material, tubing  305 ,  306 . 
   Each of the solenoid valves  207 - 209  of the pneumatic compression unit  201  is chosen to be normally closed (when the coils are not energized) to the air reservoir  205  and normally open (when the coils are not energized) between the foot compression wraps  301 ,  302  and the atmosphere. When the coils are energized, atmosphere is closed off and a two-way pneumatic flow path is established between the air reservoir  205  and the foot compression wraps  301 ,  302 . Two of the solenoid valves  208 ,  209  are designated as the left foot solenoid valve  208  and the right foot solenoid valve  209 . Through this designation, independent control is maintained for inflation of either the left foot compression wrap  301 , the right foot compression wrap  302 , or both  301 ,  302 . As will be further understood herein, the third solenoid valve  207  is necessary only in an alternate embodiment of the present invention and, even then, may be dispensed with in implementations utilizing solenoid valves  208 ,  209  having a “no-flow” capability. 
   The vacuum assisted closure unit  202  of the first configuration  200  of the preferred embodiment generally comprises a vacuum pump  212  in fluid communication with a fluid reservoir  401  through a dryer filter  214 . An intake vent  213  is provided for connection, through appropriate tubing  403 , of a porous foam dressing  402  to be inserted into a patient&#39;s wound  110 , as will be understood further herein. The dryer filter  214  serves to protect the vacuum pump  212 , which is not readily decontaminated, from the potentially hazardous or infectious wastes drawn from the wound site  110 . A port  215  is provided for releasable connection to the fluid reservoir  401  in order that the reservoir  401  may be removed and discarded when full. 
   Various sensors are provided to promote safety in the operation of the system  200 . For example, a mercury activated tilt sensor  216  indicates attitudes in which there is a danger of spilling fluids from the reservoir  401 , a push-button interlock switch  217  in the back of the reservoir port indicates improper or incomplete placement of the reservoir  401 , and a capacitively-activated level sensor  218  indicates a full condition of the reservoir  401 . Feedback from any of these sensors  217 - 219  will cause termination of vacuum pump  212  operation, as will be understood herein. Those of ordinary skill in the art will quickly recognize that many other safety features may be integrated into the system  200  as desired. 
   Further details as to the construction and operation of the intermittent pneumatic compression unit  201 , including the foot compression wraps  301 ,  302 , may be gleaned from Applicant&#39;s U.S. patent application Ser. No. 08/039,574 filed Mar. 23, 1993 which has been incorporated herein by reference. Details as to the construction and operation of the vacuum assisted closure unit  202  may be gleaned from Applicant&#39;s U.S. patent application Ser. No. 08/517,901 filed Aug. 22, 1995 which also has been incorporated herein by reference. Those products embodying the foregoing applications, commercially available from Kinetic Concepts, Inc. of San Antonio, Tex. under the trade designations “PLEXIPULSE” and “V.A.C.” are presently preferred by Applicant for implementation of this present invention. It is to be understood, however, that many other intermittent pneumatic compression and vacuum assisted closure products, as well as products for sequential therapy, wound drainage and other related therapies, are also presently available. Most all of these products should be considered functional equivalents for implementation of this present invention. 
   According to the preferred embodiment of the present invention, there is provided a single embedded micro-controller unit  203  for operation of both the intermittent pneumatic compression unit  201  and the vacuum assisted closure unit  202 . The micro-controller unit  203 , intermittent pneumatic compression unit  201  and vacuum assisted closure unit  202  all receive electrical power through a conventional wall plug  219  fitted with a hospital grade EMI/RFI filter, fuse and switch unit  220 . A power supply  222  is provided with the micro-controller unit  203  for conversion of alternating current to direct current at an appropriate voltage level for the integrated circuitry and displays  229 ,  230  present on the unit  203 . The micro-controller unit  203  is fitted with a conventional variable speed cooling fan  221 , as is known in the art. 
   Additionally, the micro-controller unit  203  is provided with a solenoid valve control circuit  223 , a compressor control circuit  224 , a vacuum pump speed control circuit  225 , a vacuum pump control circuit  226 , a pressure sensor  227  and a vacuum sensor  228 . Each circuit  223 - 226  of the unit  203  is operatively connected, directly or indirectly, to the system components being controlled and to the various sensors  227 ,  228  upon which operation of the system components is based. In operation, the solenoid valve control circuit  223  opens or closes the left and/or right solenoid valves  208 ,  209  according to a predetermined timing cycle in order to intermittently apply positive forces to substantially all, but in particular the plantar region  103 , of the patient&#39;s foot  100 . 
   In a preferred mode referred to as the “equilibrium mode,” the oscillating air compressor  204  fills the air reservoir  205  to an automatically determinable target pressure, typically in the range of 350 mm Hg as measured by the pressure sensor  227 . Once the pressure within the air reservoir  205  reaches the target pressure, the compressor  204  is shut off under the control of the compressor control circuit  224 . Upon release of the compressed air into the left and/or right foot compression wraps  301 ,  302 , an equilibrium pressure is reached between the air reservoir  205  and the wraps  301 ,  302 . This equilibrium pressure, typically in the range of 160 mm Hg, is then measured by the pressure sensor  227  whereby an accurate indication of the actual pressure delivered to the plantar region arch  103  is obtained. The compressor control circuit  224  of the micro-controller unit  203  is then able to make use of this measurement to adjust, for subsequent compression cycles, the pressure of the air initially delivered to the air reservoir  205 . Through this compression cycle-by-compression cycle adjustment scheme, the actual force applied to the patient&#39;s plantar region  103  may be robustly and accurately controlled, largely independent of wrap placement, changes in swelling or edema, or patient movements. Finally, at the end of the compression cycle and under the control of the solenoid valve control circuit  223 , air is exhausted from the left and/or right foot compression wraps  301 ,  302 , to the atmosphere, through the left and/or right solenoid valves  208 ,  209 . 
   Alternatively, a third solenoid valve  207  may be incorporated to implement a timed-mode embodiment of the present invention. In this alternate embodiment, the oscillating air compressor  204  may operate continuously, the pressure ultimately delivered to the plantar regions  103  being controlled by the timed opening and closing of the third solenoid valve  207 . According to the timed-mode embodiment, the air reservoir  205  is filled to the extent of the air compressor&#39;s capability, typically in the range of 800-900 mm Hg. Measurement of the initial pressure within the air reservoir is not necessary, so long as a relatively high pressure may be obtained within the capability of the air compressor  204 . In operation, the solenoid valve control circuit  223  opens or closes the left and/or right solenoid valves  208 ,  209  in order to pre-select either the left or right foot, or both feet, for application of positive forces to the corresponding plantar regions  103 . Substantially concurrent with the left and/or right foot selection, the solenoid valve control circuit  223  opens, for a short period of time, and then closes the third solenoid valve  207 , causing a substantially impulsive burst of air to be released from the air reservoir  205  into the left and/or right foot compression wraps  301 ,  302 . Following closure of the third solenoid valve  207 , the pressure sensor  223  measures the pressure of the air released into the left and/or right foot compression wraps  301 ,  302 . If necessary in order to achieve the desired compression wrap pressure, the open time of the third solenoid valve  207  may then be increased or decreased for subsequent compression cycles. Alternatively, the solenoid valve control circuit  223  may be implemented to produce only very short bursts of air from the air reservoir  205  into the foot compression wraps  301 ,  302 . In this implementation, the number of bursts per compression cycle, and/or the time there between, may be increased or decreased during the present compression cycle, or in subsequent compression cycles, in response to the measured pressure in the foot compression wraps  301 ,  302 . Like the equilibrium mode embodiment, the timed-mode embodiment provides a compression cycle-by-compression cycle adjustment scheme by which the actual force applied to the patient&#39;s plantar region  103  may be robustly and accurately controlled, largely independent of wrap placement, changes in swelling or edema, or patient movements. Finally, at the end of the compression cycle and under the control of the solenoid valve control circuit  223 , air is exhausted from the left and/or right foot compression wraps  301 ,  302 , to the atmosphere, through the left and/or right solenoid valves  208 ,  209 . 
   In a further modification of the timed-mode embodiment, it is possible to dispense with the third solenoid valve  207  in favor of utilizing left and right solenoid valves  208 ,  209  having an intermediate “no-flow” capability. According to this modification, the left and right solenoid valves  208 ,  209  are normally closed (when the coils are not energized) between the foot compression wraps  301 ,  302  and both the air reservoir  205  and the atmosphere, i.e. are in a “no-flow” state. Short bursts of air are then delivered from the air reservoir  205  to the left and/or right foot compression wraps  301 ,  302 , according to the foregoing timed-mode methods, by toggling the left and/or right solenoid valves  208 ,  209  between their no-flow states and their states of open flow between the air reservoir  205  and respective wrap  301 ,  302 . At the end of the compression cycle, air is exhausted from the wraps  301 ,  302  by opening the flow paths to the atmosphere. Although technologically feasible, such solenoid valves are not as of this date readily available; therefore, the three-valve implementation of the timed-mode embodiment is presently preferred over the two-valve implementation of the timed-mode embodiment. 
   In further operation, the negative pressure induced by the vacuum pump  212  is measured by a vacuum sensor  228  in fluid communication with the fluid reservoir  401  through an interposed orifice restrictor  231 . The restrictor  231  serves to protect the vacuum sensor  228  from the relatively large negative pressures necessary in the treatment process as these pressures are typically too excessive for direct measurement under presently available sensor technologies. Vacuum feedback is monitored by the vacuum pump control circuits  226  to adjust the speed, through the vacuum pump speed control circuit  225 , of the vacuum pump&#39;s motor in order to increase or decrease delivered vacuum. Additionally, the vacuum pump control circuit  226  monitors the various safety features  216 - 218  of the vacuum assisted closure unit  202  in order to effect shut down of the system  200  in the event of a hazardous condition. 
   Finally, all operations may be monitored through a liquid crystal display (LCD) readout  229  and/or light emitting diode (LED) display bar  230 . Other feedback mechanisms, such as computer interfaces and others known to those of ordinary skill in the art, may be incorporated as desired. All such user interfaces are considered within the scope of the present invention. 
   In a second configuration  500  of the preferred embodiment, shown in  FIG. 5 , the oscillating air compressor  204  and vacuum pump  212  are replaced by a single integrated compressor and vacuum pump unit  501  having internally thereto two separate plenums  502 ,  203 . Operation is identical to that of the first configuration  200 , with the exception that instead of speed control of the motors of the compressor  204  and vacuum pump  212 , a clutch mechanism similar to that of automobile air conditioning units is utilized. Such mechanisms are readily understood by those of ordinary skill in the art. In essence, the appropriate control circuits  224 ,  225  generate pulse streams by which the respective clutch mechanisms are activated in pulse width modulated fashion. 
   Referring to  FIGS. 6A and 6B , there is shown the typical application of a wound closure dressing  402  to an example ulcer  110 . Following debridement of necrotic tissue in and around the wound site  110 , a porous foam dressing  402 , having inserted therein tubing  403  for establishing fluid communication with the vacuum assisted closure unit  202 , is inserted into the site  100 . The porous foam dressing  402  and tubing  403  are anchored, and substantially sealed, within the wound site  110  by a covering of adhesive drape  404 . The drape  404  physically covers the wound site  110  as well as the margin of impact  601  surrounding the wound site  110 . A typical application, therefore, has a diameter of approximately four to eight inches, as measured if the drape  404  was laid flat. 
   In operation, the vacuum assisted closure unit  202  applies negative pressure, through the tubing  403 , to the ulcer site  110 . The porous foam dressing  402  serves to promote distribution of this negative pressure throughout the ulcer site  110 . As a result, this distribution may be considered substantially uniform. The adhesive drape  404 , itself or in concert with such other provisions as may be implemented by caregivers, serves to provide a seal around the wound site  110 . This seal provides infection control for the wound while also minimizing leaks of the negative pressures applied thereto. 
   Referring now to  FIGS. 7A-7D , there is shown the application of a foot compression wrap  301  to a foot  100 . As shown particularly in  FIG. 7A , the wrap  301  is first laid flat, generally beneath the heel, plantar arch and metatarsal head regions  102 - 104  of the foot  100 . Then, as shown in  FIG. 7B , a first tab  702  is wrapped about the dorsal aspect region  106  of the foot  100 . A second tab  703 , as shown in  FIG. 7C , is next also wrapped about the dorsal aspect region  106  of the foot  100  and secured to the outside of the first tab  702  by conventional securing means such as, for example, releasably engageable hook and loop type material as is known by those of ordinary skill in the art and commercially available under the trademark “VELCRO.” In the preferred embodiment of the present invention, a trademark “VELCRO” type patch  704  of hook-type material engages the outer surface of the wrap  301  which comprises hook compatible loop-type material. Finally, as shown in  FIGS. 7C and 7D , a third tab  705  is wrapped about the ankle region  101  of the foot  100  and secured over the dorsal aspect region  106  by a tab  706  of hook-type material. As can be seen with reference to  FIGS. 7A-7D , it is a specific object of such a foot compression wrap to cover a substantial portion of the foot with the inflatable bladder  701  integral thereto. In accordance with this object, both the deep and peripheral veins in the foot are compressed by operation of the intermittent pneumatic compression unit  201 . This enables virtually complete emptying, on an intermittent basis, of the blood in the foot  100  to which the wrap  301 ,  302  is applied. 
   As clearly shown in  FIG. 8 , depicting the foot  100  with both the porous wound dressing  402 , with drape  404 , and the foot compression wrap  301  in operable position, portions of the heel region  102  and toe region  105  are not covered by the foot compression wrap  301  notwithstanding the object of compressing substantially the entire foot  100 . This serves to enable viewing, by caregivers, of the exposed portions of the toe region  105  and heel region  102  for purposes of assessing the health of the foot  100  while the foot compression therapy is ongoing. This also readies skin on the foot  100  to minimize accumulation of moisture and the attendant risks of maceration. 
   In implementing the present invention, the wound closure dressing  402 ,  404  is applied first, in its entirety, and then the foot compression wrap  301  is applied. Due to the varying locations of ulcers on the foot  100 , application of the foot compression wrap  301  may overlap the wound dressing site  601 . Many applications within the scope of the present invention will also involve lapping the inflatable bladder  701  of the foot compression wrap  301  over the actual ulcer site  110 . In such applications, the foam dressing  402  also serves the added function of helping to cushion the actual ulcer site  110  from the compressive action of the foot compression wrap  301 . As shown in  FIG. 8 , the foot compression wrap  301  may overlap a portion of the ulcer site  110  to an extent that the inflatable bladder of the foot compression wrap  301  applies a compressive force over and onto the ulcer site  110 . 
   Once the wound closure dressing  402  is operatively situated on an ulcer site  110  on the foot  100  of the patient and the foot compression wrap  301  or  302  is applied over the wound closure dressing  402  and its drape  404 , the foot compression wrap  301  is then operatively connected to the intermittent pneumatic compression unit  201  and the wound dressing  402  is operatively connected to the vacuum assisted closure unit  202 . Vacuum assisted closure therapy and intermittent pneumatic foot compression therapy can then be concurrently implemented, i.e., either simultaneously or in some indefinitely repeated cycle between positive and negative applications during which, it is to be understood, temporal overlap of positive and negative applications may or may not occur. 
   In the preferred embodiment of the present invention, the vacuum assisted closure unit  202  is provided with various settings for both intermittent and continuous application of negative pressure to the wound closure dressing  402 . The most preferred selection of therapy options, i.e., intermittent or continuous vacuum, has not been determined at this time, although it is contemplated that either setting may be applicable. In any case, typical implementation of the invention will involve some periods of time during which negative pressure is actually applied to the ulcer site  110  notwithstanding the substantially concurrent application of compressive forces via the foot compression wrap  301 ,  302 . 
   In a second mode of application of the present invention, the applications of positive and negative pressures are timed such that negative pressure is applied to the ulcer site  110  over a first period of time and positive pressure is then applied to substantially the entire foot  100  over a second period of time. Such alternating applications of negative pressure and positive pressure over the corresponding regions of the foot are then repeated indefinitely for the duration of the therapy. 
   While the foregoing description is exemplary of the preferred embodiments of the present invention, those of ordinary skill in the relevant arts will recognize the many variations, alterations, modifications, substitutions and the like as are readily possible, especially in light of this description, the accompanying drawings and claims drawn thereto. For example, while the preferred embodiment of the present invention calls for implementation of the intermittent pneumatic compression unit  201  and the vacuum assisted closure unit  202  in a single integrated unit  200 ,  500 , those of ordinary skill in the art will recognize that, in the alternative, the present invention may be practiced, with only some corresponding loss in efficiency, with separate units for provision of intermittent compression therapy and vacuum assisted closure therapy. Such individual units are readily available and exemplary ones are described in detail in U.S. patent application Ser. No. 08/039,574 filed Mar. 23, 1993 and U.S. patent application Ser. No. 08/517,901 filed Aug. 22, 1995, each of which has been incorporated herein by reference. Products embodying each of these applications are commercially available from Kinetic Concepts, Inc. of San Antonio, Tex. under the trade designations “PLEXIPULSE” and “V.A.C.” In such an alternate embodiment, calling for separate therapy units, synchronization of the therapy timing may be provided by interface circuitry, manual adjustment of the individual units or any number of other techniques readily available to those of ordinary skill in the relevant arts. Further, other modifications, such as the provision of independent, switched control of the intermittent pneumatic compression unit  201  and vacuum assisted closure unit  202  within the single integrated unit  200 ,  500 , should be considered design expedients, within the scope of the present invention, especially in light of the foregoing exemplary description and appended claims. In any case, because the scope of the present invention is much broader than any particular embodiment, the foregoing detailed description should not be construed as a limitation of the scope of the present invention, which is limited only by the claims appended hereto.