Medical device for applying cyclic therapeutic action to a subject's foot

A medical device for applying a cyclic therapeutic action to a subject's foot, the device including a platform with at least three independently actuable inflatable bladders staggered therealong to solely underlie the subject's heel, his plantar arch and his foot's front portion including its metatarsals and its toes, respectively, whereby a travelling compressive wave can be cyclically applied to his foot's underside only.

FIELD OF THE INVENTION
 The invention is in the field of medical devices for applying a cyclic
 therapeutic action to a subject's lower limbs, and in particular to his
 feet.
 BACKGROUND OF THE INVENTION
 Many subjects suffering from a number of medical conditions including inter
 alia peripheral arterial and venous disease, hypertension, diabetes and
 deep vein thrombosis are treated by way of medical devices with one or
 more inflatable bladders for applying a cyclic therapeutic action to a
 subject's lower limbs, and in particular to his feet, for urging venous
 blood flow from his feet and legs to his heart.
 Venous blood flow can be urged by stimulation of one or both of two
 physiological mechanisms, namely, his calf's venous muscular pump and
 emptying of his foot's venous plexus. Medical devices for stimulating one
 or both of these mechanisms are illustrated and described inter alia in
 U.S. Pat. No. 2,531,074, U.S. Pat. No. 3,454,010, U.S. Pat. No. 3,683,897,
 U.S. Pat. No. 3,789,836, U.S. Pat. No. 4,003,374, U.S. Pat. No. 4,696,289,
 U.S. Pat. No. 4,945,905, U.S. Pat. No. 4,989,589, U.S. Pat. No. 5,117,812,
 U.S. Pat. No. 5,354,260, U.S. Pat. No. 5,396,896, U.S. Pat. No. 5,443,440,
 WO 88/09653, DE 30 09 408, and SU 0 1452-523.
 SUMMARY OF THE INVENTION
 In accordance with a first aspect of the present invention, there is
 provided a medical device for applying a cyclic therapeutic action to a
 subject's foot, the device comprising a platform with at least three
 independently actuable inflatable bladders staggered there along to solely
 underlie the subject's heel, his plantar arch and his foot's front portion
 including his metatarsals and his toes, respectively, whereby a travelling
 compressive wave can be cyclically applied to his foot's underside only.
 The medical device preferably has four inflatable bladders staggered along
 its platform in a non-overlapping fashion to solely underlie a foot's
 heel, its plantar arch, its metatarsus, and its toes, respectively. In
 addition, the inflatable bladders are so dimensioned and the spacing apart
 therebetween is such that they are substantially coextensive with a foot's
 underside. Also, the platforn is preferably formed with an arched plantar
 arch support for permanently supporting a foot's plantar arch and an
 arched toe support for pennanently supporting a foot's toes at their
 bases. Two basic embodiments of the medical device are envisaged:
 boot-like footwear designed to look like and be worn as conventional
 slippers worn in the home thereby precluding a person from having to
 change footwear for treatment purposes and, a normally flat, one-piece
 foldable wrap for more extended treatment periods, for example, when a
 subject is sleeping.
 In accordance with a second aspect of the present invention, there is
 provided a medical device for applying a cyclic therapeutic action to a
 subject's foot, the device comprising boot-like footwear for accommodating
 a subject's entire foot, and at least one inflatable bladder permanently
 disposed in said footwear and being in fluid communication with a pressure
 source for selectively applying pressure to the foot's underside,
 characterized in that said footwear has an externally accessible connector
 member permanently and directly attached to an exterior surface thereof,
 said conrector member being in permanent fluid communication with said at
 least one inflatable bladder and in selectively disconnectable fluid
 communication with said pressure source.
 In accordance with a third aspect of the present invention, there is
 provided a medical device for effecting dorsiflexion of a subject's foot,
 the device comprising a platform for supporting the subject's foot, and
 having an inflatable bladder for cyclically elevating the foot's front
 portion solely relative to said platform from a nonnal position there atop
 whereby the foot's front portion is flexed relative to the foot's
 remaining portion overlying said platform, said inflatable bladder having
 a first compartment overlying said platform and a second compartment
 hingedly connected to said first compartment along a trailing edge of said
 inflatable bladder directed towards the subject's heel and limiting means
 for limiting the maximum height of an edge of said second compartment
 remote from said trailing edge on inflation of said inflatable bladder
 whereby said inflatable bladder assumes an inflated triangular shaped
 configuration tapering towards the subject's heel.
 The particular design of the inflatable bladder is such that it enables a
 relatively high maximum height for a relatively small volume as say
 compared with a generally isosceles shaped inflatable of comparable
 dimensions, thereby enabling a high cycle rate even with a relatively
 small compressor.
 In accordance with a fourth aspect of the present invention, there is
 provided a medical device for effecting dorsiflexion of a subject's foot,
 the device comprising a platform for supporting the subject's foot, and
 having a wedge shaped support tapering towards the subject's heel for
 permanently supporting the foot's front portion in a flexed position
 relative to the foot's remaining portion overlying said platform; and an
 inflatable bladder mounted on said support for cyclically elevating the
 foot's front portion relative thereto from a normal position there atop.
 In accordance with a fifth aspect of the present invention, there is
 provided a medical device for applying a cyclic therapeutic action to a
 subject's foot, the device comprising a platform for supporting the
 subject's foot, and having an arched plantar arch support for permanently
 supporting the foot's plantar arch; and an inflatable bladder for
 cyclically elevating the foot's front portion relative to said platform
 from a normal position there atop whereby the subject's foot effects a
 rocking motion about said plantar arch support acting as a fulcrum-like
 member.
 In accordance with a sixth aspect of the present invention, there is
 provided a kit for installation on a wheelchair having a pair of foot
 supports for supporting a wheelchair bound subject's feet, the kit
 comprising: a rechargeable battery operated compressor; a pair of medical
 devices capable of being in fluid communication with said compressor and
 mountable on a foot support, each medical device capable of applying a
 cyclic therapeutic action to a subject's foot; and a controller for
 controlling the operation of the medical devices.
 By virtue of the kit of the present invention, a wheelchair bound subject
 can still undergo his everyday normal activities whilst receiving
 therapeutic treatment for poor venous blood flow by way of dorsiflexion of
 his feet and/or application of a travelling compressive wave to his feets'
 underside.
 In accordance with a seventh aspect of the present invention, there is
 provided a medical device for effecting plantar fiexion of a subject's
 foot, the device comprising a mounting member for mounting the medical
 device on the subject's leg, an elongated support member attached to said
 mounting member and downward depending for overlying at least a proximal
 portion of the foot's anterior surface, an inflatable bladder extending
 along the underside of said support member; and a resiliently flexible
 foot restraining member attached midway along said support member for
 encircling the foot's plantar arch.

DETAILED DESCRIPTION OF THE DRAWINGS
 With reference now to FIGS. 1-4, a medical device 1 is implemented as
 boot-like footwear 2 designed to accommodate a subject's left foot, the
 footwear 2 being constituted by a vamp 3 made of fabric-like sheet
 material and a sole 4. The vamp 3 has left and right hand vamp halves 6
 and 7 stitched together along their common edges except for their
 uppermost front portion 8 for enabling a subject's foot to be easily
 inserted into the footwear 2 and withdrawn therefrom, The vamp's heel
 portion 9 is strengthened by way of a heel patch 11 whilst a flap 12 with
 Velcro-type hook fasteners 13 for mating with Velcro-type loop fasteners
 14 on the right hand vamp half 7 (see FIGS. 3 and 4) is provided for
 fastening the footwear 2 on a subject's foot when accommodated therein.
 The flap 12 defines a generally triangular shaped pocket 16 having an
 aperture 17 adjacent an externally accessible connector member 18 secured
 to the left hand vamp half 6 towards the footwear's heel portion 9 by way
 of a tab 19 engaging a buckle-like member 21 provided along one side of
 the connector member 18 (see FIG. 4). The connector member 18 is adapted
 for selective connection to a complementary connector member 22 in
 permanent fluid communication with a pressure source 23 under the control
 of a controller 24. The connector members 18 and 22 are of the quick
 release self alignment magnetically latched type and have a first pair of
 magnets 26A and 26B at one end thereof and a second pair of magnets 27A
 and 27B at the other end of thereof. The pairs of magnets 26A, 26B and
 27A, 27B are polarized such that the connector member 22 can only be
 attached to the connector member 18 in a single pre-determined manner.
 The pressure source 24 has four outlet ports 28A-28D which are in fluid
 communication with four ports 29A-29D on the upstream side of the
 connector member 22 which, on connection of the connector member 22 to the
 connector member 18, are in turn in fluid communication with four ports
 31A-31D on the downstream side of the connector member 18 which are in
 turn in fluid communication with four inflatable bladders 32A-32D for
 independently inflating and deflating the inflatable bladders 32A-32D in
 accordance with a pre-determined heel-to-toe or toe-to-heel sequence.
 The inflatable bladders 32A-32D are adhered to the top side of a platform
 33 and are staggered there along in a non-overlapping fashion for applying
 pressure to the underside of a foot's toes, metatarsal region, plantar
 region, and heel, respectively. The inflatable bladders 32A-32D have
 laterally extending neck portions 34A-34D directed toward the left hand
 vamp half 6. The neck portions 34A-34D have apertures 35A-35D which are
 raised relative to the platform 33 and are connected to the four ports
 31A-31D via plastic tubes 36A-36D which extend between the juncture
 between the left hand vamp half 6 and the sole 4, and through the pocket
 16 to the connector member 18. In this manner the tubes 36A-36D are
 normally concealed from view and are so disposed that their presence is
 not felt by a subject when walking which would otherwise cause him some
 discomfort.
 The platform 33 is interdisposed between a relatively pliable upper sole
 member 37 and a more rigid lower sole member 38 of an inner sole
 construction 39 which is in turn interdisposed between the vamp 3 and the
 sole 4. The upper sole member 37 is peripherally attached to the vamp 3
 and the lower sole member 38 is peripherally attached to an underside of
 the upper sole member 37 and is initially provided with a lengthwise
 extending slit 39 through which the platform 33 is inserted into a
 receiving pocket 41 defined between the upper and lower sole members 37
 and 38 (see FIG. 3).
 The footwear 2 looks like conventional boot-like slippers except for the
 connector member 18 which is unobtrusively disposed on its innermost
 surface and can be worn instead of them. A subject can readily attach the
 connector member 18 to the connector member 22 by merely bringing the
 latter into proximity with the former whereupon the pairs of magnets 26
 and 27 effect a tight sealing connection therebetween for undergoing
 treatment. After the treatment, the connector member 22 can be readily
 detached from the connector member 18 by displacing his foot away from the
 former.
 With reference now to FIGS. 5 and 6, a medical device 50 is similar to the
 medical device 1 except that it is implemented as a normally flat,
 one-piece, foldable wrap 51 having a central portion 52 supporting the
 platform 33, left and right vamp portions 53 and 54, and a heel
 restraining member 56. The medical device 50 has the same platform 33 with
 the four inflatable bladders 32A-32D disposed thereon, the inflatable
 bladders 32A-32D converging towards neck portions 34A-34D with apertures
 35A-35D which in this case are raised above the platform 33 when the wrap
 51 is wrapped around a subject's foot to accommodate same. The apertures
 35A-35D are fitted with tubes 36A-36D in fluid communication with the
 connector member 18 for connection to the pressure source 23. The wrap 51
 is normally employed for long treatment periods, for example, when a
 subject is sleeping, however, by virtue of the arrangement of tubes
 36A-36D, a subject having his feet accommodated in wraps 51 can stand up
 without feeling any discomfort.
 With reference now to FIG. 7, a medical device 60 is similar to the medical
 device 10 and differs therefrom in that its platform 33 is formed with an
 arched plantar arch support 61 of height h.sub.1 for permanently
 supporting the foot's plantar arch and an arched toe arch support 62 of
 height h.sub.2 for permanently supporting the foot's toes at their base.
 The support 61 typically has a maximum height above the platform 33 of
 between about 0.7 cm and 1.2 cm and preferably about 1.0 cm whilst the
 support 62 typically has a maximum height of between about 0.3 cm and 0.7
 cm and preferably 0.5 cm above the platform 33. The supports 61 and 62
 provide a number of advantages including affording a more comfortable fit
 in a similar manner to orthopedic inner soles, facilitating the need for a
 smaller pressure source 23, and for enabling a more rapid attainment of a
 predetermined pressure in their associated inflatable bladders 32C and
 32A.
 With reference now to FIG. 8, the chart shows a heel-to-toe sequence for
 inflating and deflating the inflatable bladders 32A-32D which in
 contradistinction to the conventional distal to proximal direction of a
 travelling compression wave for effecting venous blood return, The
 heel-to-toe sequence in effect mimics a subject's walking for naturally
 stimulating his calf's venous muscular pump and his foot's venous plexus.
 With reference now to FIGS. 9-11, a medical device 70 for effecting
 dorsiflexion of a subject's foot includes a platform 71 with a heel
 support 72, a foot strap 73 and an inflatable bladder 74. The inflatable
 bladder 74 is disposed at one end of the platform 71 for solely underlying
 a foot's front portion, and is connected to a pressure source 76 under the
 control of a controller 77 for cyclically inflating it from a generally
 flat configuration (see FIG. 11A) to a wedge shaped configuration (see
 FIG. 11B) tapering toward the platform's other end.
 The inflatable bladder 74 includes a three section cover 78 having sections
 78A, 78B and 78C, the former two being formed as a pouch 79 for receiving
 a generally square single inflatable cell 81 whilst the latter one is a
 restraining member for limiting the maximum height of the inflated wedge
 shape. The inflatable cell 81 is divided into two equal sized compartments
 81A and 81B by two seams 82A and 82B lateral of a central portion 83
 enabling fluid communication between the compartments 81A and 91B. Each
 compartment 81A and 81B has a rigid member 84 lying there atop, and the
 compartment 81B is provided with an inlet port 86 which also serves to
 inflate the other compartment 81A.
 With reference now to FIG. 12, a medical device 90 is similar to the
 medical device 70 and also includes the arched plantar arch support 61 for
 effecting a cyclic dorsiflexion of a subject's foot combined with a
 rocking motion about the plantar arch support 61.
 With reference now to FIG. 13, a medical device 100 is similar to medical
 device 90 and also includes a wedge shaped support 101 tapering towards a
 foot's heel for permanently supporting a foot's front portion in a flexed
 position relative to the foot's remaining portion overlying the platform
 72, thereby facilitating better dorsiflexion which occurs with a more
 flexed position of a foot's front portion. The support 101 subtends an
 included angle .alpha. f about 30.degree. relative to the platform 72, and
 has a simple inflatable member 102 disposed thereon for effecting cyclic
 dorsiflexion of the subject's foot combined with a rocking motion about
 the plantar arch support 61.
 With reference now to FIGS. 14A and 14B, a medical device 110 has a
 platform 111 with an arched plantar arch support 112 and a pair of
 inflatable bladders 113 and 114 disposed lateral thereto and in fluid
 communication with a pressure source 116 under the control of a controller
 117 for effecting a rocking motion of a subject's foot about the plantar
 arch support 112 by way of the cyclic alternate actuation of the inflation
 bladders 113 and 114 for respectively elevating the foot's heel relative
 to the platform 111 whilst the foot's front portion is there atop and
 elevating the foot's front portion relative to the platform 111 whilst the
 foot's heel is there atop, thereby effectively rendering dorsi-plantar
 flexion of the subject's foot for facilitating emptying of the foot's
 venous plexus and activating his calf's venous muscular pump to pump
 venous blood from the subject's foot and leg towards his heart. The
 support 112 typically has a maximum height h.sub.3 above the platform 111
 of between about 1 cm and about 3 cm and preferably about 2 cm.
 With reference now to FIG. 15, a wheelchair 120 having left and right foot
 supports 121A and 121B is fitted with a medical system 122 for effecting
 dorsiflexion of a wheelchair bound subject's feet. The medical system 122
 includes a rechargeable battery operated compressor 123, a controller 124
 and two medical devices 126A and 126B. The compressor 123 and the
 controller 124 are carried on a rack 127 and the medical devices 126A and
 126B are respectively mounted on the wheelchair's foot supports 121A and
 121B whereby the medical system 122 is fully portable and therefore does
 not preclude the subject from continuing his everyday activities.
 With reference now to FIGS. 16A and 16B, a medical device 130 for plantar
 flexion of a subject's foot has a mounting member 131 for mounting the
 medical device 130 on a subject's leg. A support member 132 is
 substantially rigidly attached to the mounting member 131 for disposition
 along most of the subject's foot's anterior surface. An inflatable bladder
 133 extends along the underside of the support member 132, and is in fluid
 communication with a pressure source 134 under the control of a controller
 136. A resiliently flexible foot restraining member 137 attached about
 midway along to the support member 132 encircles the subject's foot's
 plantar arch whereupon cyclic inflation and deflation of the inflatable
 bladder 137 effects cyclic plantar flexion of the subject's foot thereby
 facilitating emptying of his foot's venous plexus and activating his
 calf's venous muscular pump to pump venous blood from the subject's foot
 and leg towards his heart.
 Various modifications and changes may be made in the configurations
 described above that come within the spirit of the invention. The
 invention embraces such changes and modifications coming within the scope
 of the claims appended hereto. For example, an inflatable bladder disposed
 under a foot's plantar arch can be divided into two inflatable bladders
 respectively disposed under a plantar arch's medial portion and its
 lateral portion. The medical devices 90, 100, 110 can also be provided
 with a heel support 72, and a foot strap 73. The wheelchair 120 can be
 provided with a medical system for applying any suitable cyclic action to
 a subject's feet by way of one of the medical devices described herein.