Patent Publication Number: US-2009227923-A1

Title: Cooling system for orthopedic cast

Description:
FIELD 
     The field generally relates to orthopedics and a system and method for controlling the temperature of a body surface contained within an orthopedic device. 
     BACKGROUND 
     The treatment of broken bones or trauma often involves the use of a wrap or cast whereby the site of injury is stabilized and/or supported for healing purposes. Conventionally, such devices are comprised of orthopedic bandages or other flexible materials used in conjunction with a settable composition. The bandages function as a buffering fabric and comprise cotton or other flexible material. The settable composition is typically a curable liquid resin that is capable of hardening upon activation by a solvent, heat or irradiation (e.g., Plaster of Paris or fiberglass). When applied to an injured appendage, the flexible materials are first wrapped around the injured area to form a flexible sleeve. Thereafter, the settable composition is applied to the outer portion of the flexible sleeve and allowed to harden, thereby immobilizing the injured limb contained therein. 
     While the hardened cast provides sufficient rigidity to support the limb, conventional casts are often uncomfortable to wear because they retain heat and cause discomfort such as itching. Further, the trauma itself often manifests itself in the form of swelling which results from the accumulation of bodily fluids underlying the skin adjacent to the site of the trauma. When the patient is wearing a hardened cast to support the area, such swelling not only results in patient discomfort, but also inhibits recovery, as the cast results in the increased application of pressure against the tissue and surrounding nerve and organ structures. Conventional hardened casts do not facilitate the reduction of swelling as such casts are not meant to be easily removed and do not expand to alleviate the increased pressure caused by such swelling. In an attempt to remedy the discomforts provided by casts of the prior art, it is known to use porous or woven base materials for the flexible sleeve. This, however, has not proven ideal because the interstices of the woven material are blocked by the curable composition when it is applied to the exterior of the flexible sleeve. 
     Alternatively, other types of conventional casts attempt to actively cool the body part within the cast. Several mechanisms have been developed to achieve this goal, including the application of cold compresses such as ice packs for prescribed periods of time to the site of trauma. This method has met with only limited success as the cold compresses are oftentimes initially too cold for the patient to comfortably endure and, as a result, the patient is unable to tolerate the cooling effects of the compresses for the prescribed period of time. Furthermore, because the compress removes heat from the body, the temperature of the compress itself progressively increases, thereby diminishing its temperature reducing affects. Such methods also require that the cast be removed for a period of time while the cold compress is in place, thereby leaving the site of trauma unsupported and vulnerable when the compress is in use. 
     It is further known to incorporate tubes into the interior of a cast such that cold fluid can be pumped therethrough to cool the limb. This method has also not proven ideal for several reasons. Primarily, the tubes must be of a sufficient diameter to allow fluid to flow therethrough, which is uncomfortable to the patient due to the resultant pressure on the injured limb within the cast. In addition, such systems require the patient to be connected to a fluid reservoir, and such systems have a tendency to leak; two undesirable characteristics given that exposure to moisture can reduce the integrity and strength of the cast. Such cast systems are also rather costly to manufacture and are not easily removed once the treatment is completed. Accordingly, it is desirable to produce a cast and therapy system that is capable of reducing the temperature of the encased body part in order to reduce swelling and to provide a more comfortable experience to the patient. 
     SUMMARY 
     In one embodiment, a wrap comprises a first inner layer, at least one wire and an outer layer. The first inner layer is formed from a flexible material and is configured to conform to the body surface of the user. At least one wire is thereafter applied to the body surface on top of the first inner layer. Once the first inner layer and the at least one wire are applied, the outer layer is applied, thereby surrounding the first inner layer and the at least one wire. In one embodiment, the outer layer comprises a hardening substance such that the outer layer provides some rigidity and protection to the layers and the body part encased therein. The wrap further comprises a plug coupled to the outer layer of the wrap. The plug is in electrical communication with the at least one wire encased within the outer layer. 
     In one embodiment of a therapy system, the therapy system includes the above-described wrap and an external cooling device. The external cooling device is capable of generating a cooling effect that can be transferred to the interior of the wrap. An electrical cord is coupled with the external cooling device and may be used to transmit the cooling effect to the wrap. When the plug is mounted on the outer layer of the wrap, the electrical cord of the external cooling device can be removably coupled therewith and used to transmit the cooling effect to the interior of the wrap. In this manner, the cooling effect generated by the external cooling device is transferred to the encased body party through the at least one wire of the wrap. 
     In an alternative embodiment, the external cooling device comprises a Peltier thermoelectric device having a plurality of conductors and a heat sink. Further, an external power supply is coupled with the external cooling device and provides sufficient power to run the external cooling device and generate the cooling effect. The external cooling device and the power supply can be combined into a single electronics package that is portable and separate from the wrap. 
     The therapy system and wrap described herein may be used to treat an injured body part of a patient. In one embodiment, a therapy system is provided comprising a wrap having a first inner layer, at least one wire and an outer layer. The therapy system also comprises an external cooling device having at least one Peltier thermoelectric device, a power supply, and an electrical cord. The power supply can either be housed within the same electronics package as the Peltier thermoelectric devices, or it can be separate, such as a wall outlet or battery source. Once the wrap is secured to the patient&#39;s injured body part as previously described above, the wrap is removably coupled with the external cooling device by way of the electrical cord. The external cooling device generates a cooling effect, which is transferred through the electrical cord and the at least one wire to the body part encased within the wrap. Because the Peltier thermoelectric devices are housed within an external cooling device, the resultant heat generated through the operation of the Peltier thermoelectric device is concentrated in the heat sink and is dissipated away from the patient. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows schematic view of one embodiment of a wrap applied to a target body surface. 
         FIG. 2A  shows a cross-sectional view of the wrap of  FIG. 1  taken along line A-A of  FIG. 1 . 
         FIG. 2B  shows a cross-sectional view of the wrap of  FIG. 1  taken along line B-B of  FIG. 1 . 
         FIG. 3  shows a cross-sectional view of another embodiment of a wrap applied to a target body surface. 
         FIG. 4  shows a schematic view of one embodiment of a therapy system comprising the wrap of  FIG. 1 . 
         FIG. 5  shows a schematic view of another embodiment of a therapy system comprising the wrap of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of scope is intended by the description of these embodiments. 
       FIGS. 1 ,  2 A, and  2 B show one embodiment of a wrap  10  applied to a target body surface  20 . Specifically,  FIG. 1  shows a side view of the wrap  10 .  FIG. 2A  shows a cross-sectional view of the wrap  10  of  FIG. 1  taken along the line A-A of  FIG. 1 .  FIG. 2B  shows a cross-sectional view of the wrap  10  of  FIG. 1  taken along the line B-B of  FIG. 1 . In this embodiment, the wrap  10  comprises an orthopedic cast that is capable of cooling the body part to which it is attached. However, it will be recognized that the wrap  10  may comprise any item that may be worn or carried on a user&#39;s body, including bandages, harnesses, dressings, splints, or any other type of dressing that may be applied to an area of trauma. The wrap  10  is adapted to be secured to a target body surface  20 , which may include, for example and without limitation, any part of a body such as a wrist, neck, arm, knee, or leg. The wrap  10  may further be formed in various shapes to fit the contours of the target body surface  20 . For example, wrist and knee wraps comprise rectangular shaped strips that can encircle the appropriate body part, whereas a shoulder wrap includes a sleeve area for mounting over the patient&#39;s shoulder and down the patient&#39;s arm. Further, more than one wrap  10  may be applied to an individual at a time and therefore may be used to treat multiple injury sites. 
     In the embodiment shown in  FIGS. 1 ,  2 A, and  2 B, the wrap  10  has a first inner layer  12 , at least one wire  14 , an outer layer  16 , and a plug  18 . The first inner layer  12  comprises a flexible material capable of conforming to the target body surface  20  to which the wrap  10  is attached. For example, the first inner layer  12  may comprise a thermally conductive material such as conductive mesh, a ventilated cushion material, a cotton material, a synthetic material, a buffering fabric, or any material that is capable of being shaped to contact and envelope the target body surface  20 . When the first inner layer  12  is wrapped around the injured area, it forms a flexible sleeve that is in direct contact with the target body surface  20 . In one embodiment, the first inner layer  12  comprises strips of material that are wrapped and fitted around the target body surface  20 . In an alternative embodiment, the first inner layer  12  is preformed into a flexible sleeve, such that the first inner layer  12  immediately fits snuggly and comfortably around the target body surface  20 , thereby reducing the amount of time required for application. 
     The outer layer  16  of the wrap  10  encases the first inner layer  12 , generally does not directly contact the underlying target body surface  20  and, as is known in the art, may comprise a settable composition. For example, the outer layer  16  may be initially applied to the inner layer  12  in a series of wet, flexible strips that harden upon drying to form an orthopedic cast. Alternatively, the outer layer  16  may be pre-formed to correspond to the shape of the inner layer  12  and/or the target body surface  20  such that when the outer layer  16  is secured to the inner layer  12  it immediately provides rigidity to the wrap  10 . 
     The outer layer  16  may comprise Plaster of Paris, fiberglass, plastic, neoprene or any other material that is capable of providing some degree of rigidity to the wrap  10 . It will be appreciated that the degree of rigidity present in the outer layer  16  may vary depending on the preferred treatment for a particular ailment. In one embodiment, the outer layer  16  functions to substantially immobilize the target body surface  20  and provide protection and support thereto. In an alternative embodiment, the outer layer  16  exhibits minimal rigidity and is relatively flexible and soft to provide functional stabilization and variable support to the target body surface  20 . By altering the rigidity of the outer layer  16 , the wrap  10  can be used to effectively treat broken bones, bone fractures or soft tissue injuries. 
     The outer layer  16  of the wrap  10  further comprises a plug  18  coupled therewith. In the embodiment shown in  FIG. 1 , the plug  18  is positioned adjacent to the target body surface in a convenient manner; however, it will be appreciated that the plug  18  may be positioned on any portion of the outer layer  16 . The plug  18  has a first end and a second end and can comprise any type of electrical connector or conductive device that is capable of receiving electrical current from a conductor. The first end of the plug  18  comprises a mating surface  30 . The mating surface  30  may be a female socket or male plug configured to respectively receive or be received by a conductive device. The second end of the plug is embedded within the outer layer  16  and is configured to couple with the at least one wire  14  such that the plug  18  and the at least one wire  14  are in electrical communication. 
     In the embodiment shown in  FIG. 1 , the first end of the plug  18  protrudes from the surface of the outer layer  16  of the wrap  10 , and the second end of the plug  18  is positioned slightly within the outer layer  16 . In this manner, the mating surface  30  of the first end of the plug  18  is positioned to receive a conductive device. Alternatively, the body of the plug  18  may be encompassed within the outer layer  16  such that only a minimal portion of the first end of the plug  18  protrudes from the outer layer  16 . Still further, the body of the plug  18  may be wholly encompassed within the outer layer  16  such that the mating surface  30  of the first end of the plug  18  is flush with the exterior of the outer layer  16  (see  FIG. 4 ). 
     The arrangement of the wrap  10  further comprises the at least one wire  14  that is capable of transmitting a cooling effect to the target body surface  20 . The at least one wire  14  is positioned between the first inner layer  12  and the outer layer  16  of the wrap  10  and comprises relatively thin, flexible, conductive members. The at least one wire  14  can be configured in any manner so long as the various parts and/or pieces of the wire  14  are in electrical communication with the plug  18 . For example, the conductive members of the at least one wire  14  may be independent elements that stem from a common trunk, or the conductive members may be configured into one continuous strand. Further, the at least one wire  14  may be arranged in a specific pattern and embedded into a mesh. It will be appreciated that the most effective configuration of the at least one wire  14  will depend on the nature of the injury to be treated and the location of the target body surface  20 . 
     Referring back to  FIGS. 1 ,  2 A, and  2 B, the at least one wire  14  extends substantially along the length of the first inner layer  12  so as to be positioned in close proximity with the target body surface  20 . In the embodiment shown in  FIG. 2A , the at least one wire  14  is coupled with the first inner layer  12  in such a manner that the at least one wire  14  does not directly contact the target body surface  20 . In an alternative embodiment, the at least one wire  14  is secured to the first inner layer  12  in a suitable manner, such as by way of electrodeposition. In yet another embodiment, the at least one wire  14  is embedded within the first inner layer  12 , thereby minimizing the thickness of the wrap  10 . 
       FIG. 3  shows an alternative embodiment of the wrap  10  of  FIGS. 1 ,  2 A, and  2 B. The wrap  300  in  FIG. 3  comprises a first inner layer  312 , at least one wire  314 , a second inner layer  315 , and an outer layer  316 . It will be recognized that the only difference between the wrap  300  and the wrap  10  is the addition of a second inner layer  315 . Depending on the particular trauma that is being treated by the wrap  300 , the second inner layer  315  may comprise any type and thickness of layer(s) deemed necessary, provided the outer layer  316  may be applied thereon. In this manner, a user can control the thickness, density and rigidity of the wrap  300 . Because the second inner layer  315  is not positioned in between the at least one wire  314  and the target body surface  20 , the second inner layer  315  does not substantially effect the transmission of cooling effect from the at least one wire  314  to the target body surface  20 . 
     Now referring to  FIG. 4 , a schematic view of one embodiment of a cast cooling system  400  is shown. The cast cooling system  400  comprises wrap  410 , which is identical to the wrap  10  of  FIGS. 1 ,  2 A, and  2 B. Similar to wrap  10 , wrap  410  comprises a first inner layer  412 , at least one wire  414 , and outer layer  416 , and a plug  418 . The cast cooling system  400  further comprises an external cooling unit  450 . As shown in  FIG. 4 , the external cooling unit  450  comprises a cooling device  454  and a power supply  460 , both housed within a housing  452 . The housing  452  provides protection to the components housed therein and may be any housing unit known in the art. In one embodiment, the housing  452  is stationary and configured to rest in one location. In an alternative embodiment, the housing  452  is mobile, such that the housing may be easily maneuvered by the user. For example, the housing  452  may have wheels attached thereto or comprise any other mechanism capable of facilitating the mobility of the housing  452 . Accordingly, because the power supply  460  is contained within the housing  452 , the external cooling unit  450  may be portable and transferred by the user at their convenience. 
     As previously described, the housing  452  contains the cooling device  454 . The cooling device  454  may comprise any cooling device known in the art that is capable of producing a cooling effect transmittable through a conductive material. In the embodiment shown in  FIG. 4 , the cooling device  454  comprises a Peltier thermoelectric device having at least two conductors  456  and a heat sink  458 . 
     Generally, the Peltier thermoelectric device is a solid-state, active heat pump that transfers heat from one side of the device to the other against a temperature gradient (from cold to hot). The conductors  456  of the Peltier thermoelectric device are comprised of dissimilar materials connected to each other at least two junctions. Due to these junctions and the use of dissimilar materials, when the Peltier thermoelectric device is connected to a DC voltage source, the current drives a transfer of heat from one junction to the other. In this manner, the Peltier thermoelectric device causes one side to cool, while the other side heats up. Accordingly, the Peltier thermoelectric device achieves heat transfer through the consumption of electrical energy. 
     The cooling device  454  obtains the requisite electrical energy from the power supply  460 . In the embodiment shown in  FIG. 4 , the power supply  460  is contained within the housing  452  and is electronically coupled the cooling device  454 . The power supply  460  may be any power supply that is capable of producing a sufficient amount of energy to support the functionality of the cooling device  454 . In the embodiment shown in  FIG. 4 , the power supply  460  is of the type that generates DC voltage. 
     In an alternative embodiment, the power supply may be independent of the housing  452  and the external cooling device  450 . Now referring to  FIG. 5 , wherein identical numerals indicate identical parts, a schematic view of an alternative embodiment of the therapy system  400  is shown. In this embodiment, a power supply  570  is positioned outside of the housing  452  and the housing  542  only contains the cooling device  454  and any other electrical components necessary to generate and transmit a cooling effect. Further, the housing  452  comprises a power cord  580  extending therefrom. The end of the power cord  580  that is not attached to the housing  452  comprises a detachable coupling  588  configured to mate with the external power supply  570 . The external power supply  570  may be any power supply known in the art, such as a wall outlet, generator, or battery source. In one embodiment, the detachable coupling  588  is configured to couple with a wall outlet such that the cooling device  554  is portable and convenient to use. Further, it will be recognized that any combination of power supplies may be used in connection with the therapy system  400 . For example, a power supply  460  may be housed within the housing  452  and an external power supply  570  may be removably coupled with the housing  452  by power cord  580 . 
     Now referring back to  FIG. 4 , the external cooling unit  450  further comprises an electrical cord  462  that extends from the housing  452  and is in electrical communication with both the cooling device  454  and the power supply  460 . The electrical cord  462  comprises any cord that is capable of transmitting electrical current and has a first end and a second end. The first end of the electrical cord  462  is coupled with the housing  452 , thereby forming an electrical connection with the cooling device  454  contained therein. The second end of the electrical cord  462  comprises a detachable coupling that is configured to removably mate with the mating surface  430  of the plug  418 . When the detachable coupling of the electrical cord is mated with the mating surface  430  of the plug  418 , the electrical cord  462  provides an electrical connection between the external cooling unit  450  and the wrap  410 . In this manner, the at least one wire  414  is in electrical communication with the cooling device  454  and the power supply  460  of the external cooling unit  450 . 
     The wrap  410  is applied by securing the various layers thereof around the target body surface  20 . It will be recognized that the layers of the wrap  410  may be applied to the target body surface  20  in any order so long as the outer layer  416  comprises the outermost component. For example, in one embodiment, the first inner layer  412  is applied first so that the first inner layer  412  is in direct contact with the target body surface  20 . Thereafter the at least one wire  414  is applied over the first inner layer  412 . In an alternative embodiment, the at least one wire  414  is embedded within the first inner layer  412  and the first inner layer  412  and the at least one wire  414  are applied in tandem. 
     After the first inner layer  412  and the at least one wire  414  are applied, the plug  418  is positioned in such a manner that the plug  418  can be easily coupled with the outer layer  416  of the wrap  10 . Further, the mating surface  430  of the plug  418  is positioned to be exposed to the exterior of the wrap  410 . Thereafter, any number of filler layers may be wrapped around the first layer  412  and the at least one wire  414  (e.g., second inner layer(s)  315 ). Such filler layers may comprise cushioning for the patient&#39;s comfort, or functional layers for compression to increase the support provided to trauma site. 
     Once all of the interior layers have been wrapped around the target body surface  20 , the outer layer  416  is applied. The exact method used to apply the outer layer  416  will depend upon what type of material selected to form the outer layer  416 . For example, when the outer layer  416  comprises Plaster of Paris, a bandage impregnated with plaster is moistened and wrapped around the interior layers of the wrap that have been previously applied to the target body surface  20 . Thereafter, the bandage is allowed to set and harden, thereby forming a hard, protective coating. In an alternative embodiment, the outer layer  416  comprises a neoprene bandage, which is fitted over the previously applied interior layers. Thereafter, straps are employed to secure the neoprene-based outer layer  416  in place. Irrespective of the type of material selected for the outer layer  416 , the plug  418  is embedded within the outer layer  416  such that the mating surface  430  is positioned to receive the detachable coupling of the electrical cord  462 . The exact placement of the plug  418  in the outer layer  416  is dependent upon the particular requirements of the injury at issue. 
     In operation, the cast cooling system  400  can be used to treat an area of trauma by supporting the injured area and concurrently reducing the temperature thereof to facilitate the reduction of swelling, pain or discomfort in the area. Further, because the external cooling unit  450  is removably coupled with the wrap  410 , the cooling therapy can be applied in a convenient, non-intrusive manner. For example, when the patient is experiencing pain or discomfort to the area of trauma, he or she can simply plug the external cooling unit  450  into the wrap  410  to initiate the cooling therapy. When the therapy session is complete, the patient simply unplugs the wrap  410  from the external cooling unit  450  and returns to his or her normal activities, unhindered by any extraneous equipment. 
     The cooling effect is generated by the external cooling unit  450  and transferred to the target body surface  20  by the at least one wire  414 . As previously indicated, when the cooling device  454  operates, the current flowing through it has two effects: cooling and heating. Depending in the direction of the current flowing through the conductors  456 , the cooling effect and the heating effect can be transmitted in different directions. Accordingly, current is applied to the cooling device  454  in such a manner so that the cooling effect is transmitted through the electrical cord  462  to the at least one wire  414 , and the heating effect is channeled to the heat sink  458 . In this manner, the at least one wire  414  within the wrap  414  cools the target body surface  20  without removing the wrap  410 . 
     As noted above, the unwanted heating effect generated by the cooling device  454  is accumulated in the heat sink  458  and allowed to dissipate into the surrounding atmosphere. The heat sink  458  is located within the housing  452  and, as such, the heat is dispelled away from the user. Accordingly, the heat released from the heat sink  458  is not proximate to the user and therefore does not interfere with the cooling therapy. While the methods described herein are illustrated using a Peltier device as the cooling device  454 , it will be recognized that any cooling device may be used, provided the cooling device is capable of transferring the cooling effect to the at least one wire  414  within the wrap  410  through the electrical cord  462 . 
     When the treatment to the user&#39;s body part is complete and/or it is necessary to remove the wrap  410  from the target body surface  20 , the wrap  410  may be removed using methods known in the art. For example, a cast saw may be used to simply cut the wrap  410  from the user&#39;s body part. The various layers of the wrap  410 , including the at least one wire  414 , are easily cut through and removed. Thereafter, the entire wrap  410  may be discarded and replaced if necessary. It will be recognized that the application and removal of the wrap  410  can be completed by efficient processes that are known in the art. 
     The embodiments described herein are only offered by way of non-limiting examples, as other versions are possible. It is anticipated that a variety of other modifications and obvious changes will be apparent to those having ordinary skill in the art and such modifications and changes are intended to be encompassed within this description and the following and any later added claims.