Patent Publication Number: US-2009227921-A1

Title: Bendable sole for compression foot cuff

Description:
FIELD OF THE INVENTION 
     The present invention generally relates to a sole for a compression foot cuff, and more particularly to such a sole that is bendable. 
     BACKGROUND 
     Compression devices for applying compressive forces to a selected area of a wearer&#39;s anatomy are generally employed to improve blood flow in the selected area. Compression devices that provide intermittent pulses of a compressed fluid (i.e. air) to inflate at least one inflatable chamber in a cuff or sleeve are particularly useful. This cyclic application of pressure provides a non-invasive method of prophylaxis to reduce the incidence of deep vein thrombosis (DVT), and the like. These compression devices find particular use during surgery on patients with high-risk conditions such as obesity, advanced age, malignancy, or prior thromboembolism. Patients who develop this condition often have swelling (edema) and tissue breakdown (venous stasis ulcer) in the lower leg. When a DVT occurs, the valves that are located within the veins of the leg can be damaged, which in turn can cause stasis and high pressure in the veins of the lower leg. 
     Generally, these compression devices are fluidly coupled to a source of pressurized fluid by one or more air tubes. Additionally, each compression device includes a flexible shell having one or more bladders disposed therein. The compression device is placed around the patient&#39;s foot or other selected portion whereupon a pressurized fluid is delivered into the bladder creating pressure at the part or parts of the body in contact with the bladder. 
     Compression cuffs adapted for use with a patient&#39;s foot may be used by themselves or combined with one or more additional compression cuffs or sleeves that are disposed on portions of a patient&#39;s leg for improving the treatment regimen. In general, each of the additional compression sleeves includes a plurality of separate inflatable chambers that are progressively arranged along a longitudinal axis of the sleeve from a lower portion to an upper portion of the limb. A pressure source, e.g. a controller, is provided for intermittently forming a pressure pulse within these inflatable chambers from a source of pressurized fluid during periodic compression cycles. The compression sleeves provide a pressure gradient along the patient&#39;s limbs during these compression cycles which progressively decreases from the lower portion to the upper portion of the limb (e.g. from the ankle to the thigh). 
     Compression cuffs that are adapted for use with a patient&#39;s foot generally include a heel strap with a tab portion that is adapted to fit around a portion of the patient&#39;s heel. This arrangement allows the compression cuff to be wrapped around and releasably attached to the patient&#39;s foot. The compression cuff may include a generally planar, rigid sole to direct expansion of the inflatable chamber toward the wearer&#39;s foot. The rigid sole needs to be located under that portion of the inflatable member that is acting on the portion of the foot to produce blood flow out of the foot. Applicants have discovered that the conventional planar, rigid sole may be uncomfortable for the wearer because of the rigidity of the sole. 
     Examples of compression cuffs are disclosed in U.S. Pat. Nos. 4,013,069 and 4,030,488 to Hasty, U.S. Pat. Nos. 4,029,087 and 5,795,312 to Dye, U.S. Pat. No. 5,626,556 to Tobler et al., and U.S. patent application Ser. No. 11/761,212 to Meyer et al., all of which are currently owned by Tyco Healthcare Group LP and are incorporated by reference herein in their entireties. Other examples of compression cuffs are disclosed in U.S. Pat. No. 4,696,289 to Gardner et al., U.S. Pat. No. 5,989,204 to Lina and U.S. Pat. No. 5,345,260 to Cook. An example of compression treatment method is disclosed in U.S. Pat. No. 6,231,532 to Watson et al., which is owned by Tyco Healthcare Group LP, the contents of which are hereby incorporated by reference herein in their entirety. 
     SUMMARY 
     In one aspect, a compression foot cuff for applying compression to a wearer&#39;s foot generally comprises an inflatable member including first and second fluid impermeable layers secured to one another to define an inflatable chamber. A is sole secured to the foot cuff in generally opposing relationship with the first layer of the inflatable member. The sole has a major axis extending between opposite ends of the sole. The sole includes a plurality of spaced apart, generally rigid members hingedly secured to one another along the major axis of the sole so that the sole is generally bendable out-of-plane. 
     In another aspect, a method of making a compression foot cuff for applying compression to a wearer&#39;s foot generally comprises forming a bladder by joining together generally opposed first and second layers of fluid impermeable material. A sole is formed including a plurality of generally rigid members secured to one another along an axis of the sole by a generally flexible member that is bendable so that the sole is generally bendable out-of-plane. The sole is secured in position relative to the bladder so that the sole is generally adjacent to the first layer of the bladder and in generally opposing relationship thereto. 
     In yet another aspect, a compression foot cuff for applying compression to a wearer&#39;s foot generally comprises an inflatable member including first and second fluid impermeable layers secured to one another to define an inflatable chamber. A sole is secured to the foot cuff in generally opposing relationship with the first layer of the inflatable member. The sole has a major axis extending between opposite ends of the sole. The sole includes a plurality of spaced apart, generally rigid members hingedly secured to one another along the major axis of the sole so that the sole is generally bendable out-of-plane. The sole is configured for bending out-of-plane along axes perpendicular to its major axis in a direction causing a central area of the sole to move toward the inflatable member and longitudinal ends of the sole to move away from the inflatable member, and to resist bending out-of-plane along the perpendicular axes causing the central area of the sole to move toward the inflatable member and the longitudinal ends of the sole to move away from the inflatable member. 
     In another aspect, a method of making a compression foot cuff for applying compression to a wearer&#39;s foot generally comprises forming a bladder by joining together generally opposed first and second layers of fluid impermeable material. A sole is formed including a plurality of generally rigid members secured to one another along an axis of the sole by a generally flexible member that is bendable so that the sole is bendable out-of-plane in one direction about a bend axis perpendicular to the axis of the sole and is generally not bendable out-of-plane in an opposite direction. The sole is secured in position relative to the bladder so that the sole is generally adjacent to the first layer of the bladder and in generally opposing relationship thereto. Forming the sole comprises forming the rigid and flex members to bend out-of-plane in one direction about a bend axis perpendicular to the axis of the sole, and to resist bending out-of-plane in the opposite direction. 
     In yet another aspect, a compression foot cuff for applying compression to a wearer&#39;s foot generally comprises an inflatable member including first and second fluid impermeable layers secured to one another to define an inflatable chamber. A sole is secured to the foot cuff in generally opposing relationship with the first layer of the inflatable member. The sole includes biasing member biasing the sole out-of-plane along axes perpendicular to its major axis in a direction causing a central area of the sole to move toward the inflatable member and longitudinal ends of the sole to move away from the inflatable member. 
     Other features will be in part apparent and in part pointed out hereinafter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded perspective of a first embodiment of a compression foot cuff in accordance with the present disclosure; 
         FIG. 2  is a perspective of a bladder of the foot cuff with a sole of a first embodiment attached thereto; 
         FIG. 3  is a perspective of the sole in  FIG. 2 ; 
         FIG. 4  is a front elevation of the sole in  FIG. 3 ; 
         FIG. 5  is similar to  FIG. 4  with the sole bent in a concave configuration; 
         FIG. 6  is similar to  FIG. 4  with the sole bent in a convex configuration; 
         FIG. 7  is a perspective of a bladder of a foot cuff with a sole of a second embodiment attached thereto; 
         FIG. 8  is a perspective of the sole in  FIG. 7 ; 
         FIG. 9  is a front elevation of the sole in  FIG. 8 ; 
         FIG. 10  is similar to  FIG. 9  with the sole bent in a convex configuration; 
         FIG. 11  is a perspective of a sole of a third embodiment; 
         FIG. 12  is a front elevation of the sole in  FIG. 11 ; 
         FIG. 13  is a perspective of a sole of a fourth embodiment; and 
         FIG. 14  is a front elevation of the sole in  FIG. 13 . 
     
    
    
     Corresponding reference characters indicate corresponding parts throughout the drawings. 
     DETAILED DESCRIPTION OF THE DRAWINGS 
     Referring now to the drawings, a compression foot cuff for applying compressive pressure to a wearer&#39;s foot is generally indicated at  10 . The foot cuff is adapted for use in a compression therapy system, which further includes a supply of pressurized air (not shown) and tubing connecting the supply of pressurized air to the foot cuff. 
     As shown best in  FIG. 1 , the foot cuff  10  includes an envelope, generally indicated at  12 , substantially enveloping or enclosing a bladder, generally indicated at  14 . The envelope  12  includes an inner contact layer  16  and an outer layer  18  secured to one another generally adjacent to corresponding perimeters of the layers to define an interior space for receiving and substantially enclosing the bladder  14  (broadly, “an inflatable member”) therein. The contact layer  16  and the outer layer  18  may be fixedly secured to one another at their peripheral edge margins, such as by heat welding, adhesives, sewing or other suitable ways. Alternatively, the contact layer  16  and the outer layer  18  may be releasably secured to one another. In use the contact layer  16  is adjacent to the wearer&#39;s foot and the outer layer  18  is located farthest from the foot. As used herein, the terms “inner” and “outer” indicate relative positions of respective components and surfaces with respect to the skin of the wearer&#39;s body part when the compression device is secured to the body part, and as such, an “inner” component or surface is more adjacent to the skin of the body part than an “outer” component or surface. 
     Contact layer  16  and outer layer  18  of the envelope  12  include ankle strap portions  19   a  and  19   b  respectively. Ankle strap portions  19   a ,  19   b  have a longitudinally projecting configuration for wrapping about a portion of the foot adjacent to the ankle. The ankle strap portions  19   a ,  19   b  can be sewn, RF welded, or sonic welded. However, in the illustrated embodiments, the ankle strap portions  19   a ,  19   b  are formed as one piece with the contact layer  16  and outer layer  18 , respectively. 
     Contact layer  16  of the envelope  12  is adapted for contacting the foot. Contact layer  16  is in one embodiment fabricated from a chemically treated material, with wicking ability, for wicking away moisture from the skin. In one embodiment, contact layer  16  includes a mesh-like fabric capable of wicking moisture away from the patient&#39;s skin. Furthermore, the contact layer  16  can be faced with a soft material toward the treatment surface of the patient. For example, the material can be a thin layer of open celled porous foam, napped cloth, or a layer of vapor permeable cloth permeable. It is understood that the cuff  12  may not include a contact layer within the scope of the present invention. 
     Outer layer  18  of the envelope  12  includes an opening  20  for permitting a pressurized fluid inlet passage therethrough. Outer layer  18  is configured for providing the attachment surface for a hook and loop feature of cuff  12 , as will be described in more detail herein below. Moreover, the outer layer  18  provides a soft material for cushioning effect against the top portion of the feet and may be fabricated from similar materials as contact layer  16  and in similar dimensions therewith for corresponding geometry. Alternatively, outer layer  18  may be fabricated from a laminated material, such as, for example, sontara fabric, open cell urethane foam, or loop fabric. It is understood that the cuff  12  may not include an outer layer within the scope of the present invention. 
     The bladder  14  is configured for positioning against the bottom portion of the foot. The bladder  14  includes an outer layer  22  and an inner layer (not shown) of air impermeable material (e.g., PVC) joined together in a suitable manner along a line  26  adjacent to their peripheries to define a single inflatable chamber  27 . The layers  22  may be joined to one another in a suitable manner such as by radio frequency (RF) welding. Other ways of joining the layers  22  include sewing, adhesive, heat sealing, etc. It is understood that the bladder  14  can include more than one inflatable chamber  27  within the scope of the present invention. The inflatable chamber  27  of the bladder  14  is adapted for receiving and retaining a pressurized fluid (e.g. air) for exerting compressive pressure to the foot during successive pressure application cycles. The inflatable chamber  27  has a port  34  and a tube  35  connected to the port for air or fluid to be introduced into the chamber during the start of a compression cycle and to be exhausted to end the compression cycle. The port  34  of the illustrated embodiment is a plastic component that is secured such as by heat welding or other means to the bladder  14 . It is understood that other ways of introducing air or fluid into the chamber  27  are within the scope of the invention. 
     Referring still to  FIGS. 1-6 , a sole, generally indicated at  36 , is disposed between the outer layer  18  of the envelope  12  and the outer layer  22  of the bladder  14  and is positioned to underlie the foot in use. The sole  36  may be secured to the outer layer  22  of the bladder or to the outer layer  18  of the envelope  12  using adhesive, for example, or the sole may be secured in position in other ways without departing from the scope of the invention. Generally, the sole  36  is bendable out-of-plane to provide flexibility and increased comfort to the patient. It is believed the sole  36  provides a counterforce to the outer layer  22  of the bladder  14  as the bladder is expanding to direct expansion toward the contact layer  16  and the user&#39;s foot. In this way, the inner layer  24  expands outward more than the outer layer  22  to direct compressive force toward the user&#39;s foot. 
     The sole  36  includes a plurality of generally rigid members  38  that are spaced apart along a major axis A 1  ( FIG. 3 ) of the sole extending between opposite ends. The generally rigid members  38  themselves are substantially unbendable in-plane and out-of-plane. The generally rigid members are hingedly secured to one another along the major axis A 1  by generally flexible members  40 . The generally flexible members  40  act as living hinges to allow the sole  36  as a whole to bend out-of-plane. More specifically and referring to  FIGS. 5 and 6 , the opposite axial ends of the sole  36  are bendable or flexible about a central transverse axis A 2  lying in a plane generally transverse to the major axis A 1 . The axial ends of the sole  36  may be flexed either inward ( FIG. 5 ) or outward ( FIG. 6 ) about the central transverse axis A 2  so that the sole may be bent in a generally concave configuration ( FIG. 5 ) or in a generally convex configuration ( FIG. 6 ), respectively. In the illustrated embodiment, the sole  36  is formed as a one-piece, integral structure. The sole  36  of the illustrated embodiment may be constructed from a polypropylene material using injection molding manufacturing techniques. As shown best in  FIGS. 4-6 , the generally flexible members  40  are thinner than the generally rigid members so that the generally flexible members function as living hinges. Other ways of making the sole  36  bendable out-of-plane, including other ways of making the generally rigid members  38  hingedly secured to one another, are within the scope of the present invention. For example, the generally rigid members  38  may be formed separately and secured to one another by hinge pins or other devices to make a hinged connection. 
     Referring to  FIG. 1 , hook fasteners  56 ,  58  are provided for securing the wrapped cuff  12  around a foot, and are positioned on the outer layer  18  of the cuff. Hook fastener  56  is mounted to strap portion  19   b  of outer layer  18  of foot cuff  12  while hook fastener  58  is mounted on a surface of outer layer  18 . In use, when ankle strap portions  19   a ,  19   b  are wrapped about the back of the foot, hook element  56  engages outer layer  18  to facilitate mounting of foot cuff  12  on the foot. An identification tab (not shown) may also be included for providing information such as the model number and manufacturer name. Hook fasteners  56 ,  58  may have tabs (not shown) without fastening material thereon to provide convenient gripping locations on the hook fasteners to thereby allow the practitioner to easily remove the hooks from the outer face  18   b  of outer layer  18 . The use and operation of the foot cuff  12  for applying compression therapy to the wearer&#39;s foot is generally known in the art and will not be described herein. 
     Referring now to  FIGS. 7-10 , a second embodiment of a sole for a compression device is generally indicated at  136 . This embodiment is similar to the prior embodiment, and therefore, like components are indicated by corresponding reference numerals, plus  100 . The main difference between the present sole  136  and the prior embodiment  36  is that the present sole is constructed to be bendable out-of-plane in one direction only. More specifically, the axial ends of the present sole  136  are bendable only outward about a central transverse axis A 2  so that the sole is configurable in a convex configuration ( FIG. 10 ). In other words, the sole  136  can bend in a direction that would cause the central portion of the sole to move in a direction toward the bladder  114  and the ends to move in a direction away from the bladder. This is not to say, the sole  136  moves relative to the bladder  114 , but the bladder provides a reference frame for describing how the sole may bend. The sole  136  is generally not configurable in a concave configuration. Stated another way, the sole  136  resists bending in a direction causing the central portion of the sole to move away from the bladder  114  and the ends of the sole to move in a direction toward the bladder. In this way, the sole  136  is bendable to generally conform to the arch of a bottom of a foot while it is believed that the sole will provide a better counterforce to the outer layer  22  of the bladder  14  as the bladder is expanding to direct expansion toward the contact layer  16  and the user&#39;s foot. 
     In the illustrated embodiment, the sole  136  includes a plurality of generally rigid members  138  that are spaced apart along a major axis A 1  of the sole extending between opposite ends. The generally rigid members  138  themselves are substantially not bendable in-plane or out-of-plane. The generally rigid members  138  extend generally transverse to the major axis A 1  of the sole and have inner surfaces that are generally planar. The inner surfaces are in generally opposing relationship with the outer layer  22  of the bladder  14 . The generally rigid members  138  taper away from the bladder  114  so that the members have generally triangular cross-sectional shapes. The generally rigid members are hingedly secured to one another along the major axis A 1  by generally flexible members  140 . Referring to  FIGS. 8-10 , transverse slots  142  in the flexible members  140  extending through the inner surface of the sole  136  allow the axial ends of the sole to flex or bend outward about a central transverse axis and prevent the ends from bending inward so that the sole as a whole is bendable only in the convex configuration. It will be understood that adjacent rigid members  138  will engage each other after only a small amount of bending toward a con cave configuration. Thus, bending in this direction is resisted. Other ways of making the sole capable of unidirectional, out-of-plane bending is within the scope of the present invention. In the illustrated embodiment, the sole  136  is formed as a one-piece, integral structure. The sole of the illustrated embodiment may be constructed from a polypropylene material using injection molding manufacturing techniques. 
     Referring to  FIGS. 11 and 12 , a third embodiment of a sole for a compression device is generally indicated at  236 . This embodiment is similar to the prior embodiment, and therefore, like components are indicated by corresponding reference numerals, plus  200 . The main difference between the sole  236  and the first embodiment  36  is that the sole  236  comprises a flexible member  241   a  and a biasing member  241   b . The biasing member  241   b  is secured to the sole  236  to bias it in the generally convex configuration. The flexible member  241   a  can be made of a soft material and provide no resistance to bending in any direction. The biasing member  241   b  of the sole  236  provides resistance to bending to the concave configuration and thus supports the bladder to apply pressure to the foot, when the bladder is inflated. However, the biasing member  241   b  preferably provides less resistance to bending toward the concave configuration. In the illustrated embodiment, the biasing member  241   b  is secured to flexible member  241   b  on the outer side of the sole  236  (i.e., adjacent to the outer layer  18  of the envelope  12 ), although the biasing member may be secured to the inner side of the sole within the scope of the invention. The biasing member  241   b  may be formed from a generally resilient material including plastic and metal. It is understood that the sole  236  may be of other configurations within the scope of the invention. Although the biasing member  241   b  has been shown as a flat, uniform piece of material, it may have other configurations, including configurations that are not contiguous with the perimeter of the flexible member  241   a.    
     Referring to  FIGS. 13 and 14 , a fourth embodiment of a sole for a compression device is generally indicated at  336 . This embodiment is similar to the first embodiment, and therefore, like components are indicated by corresponding reference numerals, plus  300 . The main difference between the present sole  336  and the first embodiment  36  is that the sole of the present embodiment is a laminate including a compressible member  343  and a biasing member  341 secured to the compressible member to bias it in the generally convex configuration. In the illustrated embodiment, the biasing member  341  is secured to an outer side of the compressible member  343  (i.e., adjacent to the outer layer  18  of the envelope  12 ), although the biasing member may be secured to the inner side of the compressible member within the scope of the invention. The biasing member  341  may be formed from a generally resilient material including plastic and metal. The compressible member  343  may be formed from a spongy or generally compressible material. The compressible member  343  provides increased comfort to the wearer. Other materials and other configurations of the biasing member and the compressible member are within the scope of the present invention. 
     Having described the invention in detail, it will be apparent that modifications and variations are possible without departing from the scope of the invention defined in the appended claims. 
     When introducing elements of the present invention or the preferred embodiment(s) thereof, the articles “a”, “an”, “the” and “said” are intended to mean that there are one or more of the elements. The terms “comprising”, “including” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. 
     In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained. 
     As various changes could be made in the above constructions, products, and methods without departing from the scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.