EP2155129A2

EP2155129A2 - Plantar orthesis for treatment of venous insufficiency

Info

Publication number: EP2155129A2
Application number: EP08737458A
Authority: EP
Inventors: Carlo Subini
Original assignee: Rizzoli Ortopedia SpA
Current assignee: Rizzoli Ortopedia SpA
Priority date: 2007-04-19
Filing date: 2008-04-17
Publication date: 2010-02-24
Also published as: WO2008129389A3; ITPI20070051A1; WO2008129389A2

Abstract

Plantar orthesis (1) for treatment of lower limb diseases of a patient, in particular, owing to phenomena of venous insufficiency, comprising an insole (2) having a rearfoot support zone (41), a midfoot support zone (42) and a transversal stepped protrusion (43). The insole is made so that, during the gait of a patient, the rearfoot support zone (41), receiving a pressure from the patient's foot in the rearfoot support phase (51), causes the midfoot support zone and the plantar arch zone (52) that produces a pressure to the same. This is combined with the action of the transversal stepped protrusion (43), which is adapted to cause opening/closing the metatarsal heads of the forefoot (53), to assist the blood reflux.

Description

TITLE PLANTAR ORTHESIS FOR TREATMENT OF VENOUS INSUFFICIENCY

DESCRIPTION

Field of the invention The present invention relates to a foot orthosis for treatment of lower limb diseases, in particular, of the chronic venous insufficiency. Description of the prior art

As well known, chronic venous insufficiency, or CVI, is a rather common disease due to bad blood circulation that tends to stop at the ends of the body. The lower limbs have a deep venous circulation and a surface circulation, connected to each other by many vessels, or perforating veins. The venous tree, furthermore, has inner valves capable of keeping the blood flow in an antigravitational direction.

The return path of the blood from the periphery to the heart is carried out, in fact, against the force of gravity and is assisted especially by squeezing the plantar arch by the body weight and by the contraction of the calf muscle.

More in detail, the return path of the blood from the lower limbs to the heart begins in the periphery, at the capillary branches and is assisted by squeezing the venous sponge in the plantar arch and by muscle pumping, i.e. by the contractions of the muscles of the calf that cause pumping the blood in a thoracic direction, and additionally the intravasal valves that close and prevent the blood to fall backwards. When the blood cannot be pumped upwards, owing to a plurality of possible factors, it stays in the veins of the legs. The blood stagnation causes an increase of the pressure in the veins, enlarging the vein walls and causing the blood to leak into the tissues. The stagnation causes, furthermore, an inflammatory process with accumulation of oxygen free radicals that can damage the cells of the vein walls. The oxidation makes the vessels more fragile and permeable, contributing to the formation of edema and to worsening the clinical history.

A diffused disease caused by a bad blood circulation in the lower limbs is called chronic venous insufficiency, or CVI. This is usually recognized as two large groups of venous insufficiencies, according to the prevailing cause thereof. The first one is called organic venous insufficiency, caused by real alterations to the veins, such as varicous veins, after-effects of venous thrombosis, etc., whereas the second one is called functional venous insufficiency, i.e. due to hyper- work of the veins caused by an excessive activity, posture modification, lymphedema, etc. The varicous veins, which are permanent dilations of the wall of the veins, are associate, in particular, to the number of pregnancies, to the use of oral contraceptives, to water retention and to overweight. Other factors that trigger the onset of varicous veins are familiarity, working posture, chronic constipation. Even a past venous thrombosis of the deep veins assists the onset of varicous veins with a mechanism of hemodynamic compensation.

Physical defects such as flatfoot or hollow foot, which change the normal biomechanics of the gait, and cause posture alterations of the back and of the knees, not assist the pushed of the blood towards the heart and then cause venous insufficiency. In case of lymphedema, i.e. of alteration of the lymphatic vessels, there is a functional overload of the venous system that that makes up for the missing work of the lymphatic system.

A variety exists of types of plantar orthoses used for treatment of lower limb diseases correlated to a low blood circulation. The majority of such plantar orthoses has a stiff protrusion at the plantar arch of with the object of stretching the tissues of the plantar boundary of the foot and of avoiding collapse of astragalus bone. However, such plantar orthoses succeed only in part to restore the blood circulation of the foot.

In EP 0060253 an insole of resilient material is described equipped with expandable chambers, which according to the load on the patient's foot cause a reaction in determined points of the foot sole. However, this plantar orthosis is not capable of applying an effective action that reactivates the blood circulation on the lower limbs of the patient. Summary of the invention

It is then a feature of the present invention to provide a plantar orthosis for treatment of lower limb diseases, in particular, of venous insufficiency, capable of restoring the venous pumping responsible of the blood reflux.

It is also a feature of the present invention to provide a plantar orthosis for treatment of lower limb diseases, in particular, of venous insufficiency, which is more effective with respect to similar devices of the prior art.

It is another feature of the invention to provide a plantar orthosis that is structurally easy and cheap.

These and other features are accomplished with one exemplary plantar orthosis, according to the present invention, for treatment of lower limb diseases, comprising: an insole adapted to be arranged in a shoe and to support the gait of a patient, the insole having a rearfoot support zone, a midfoot support zone and a forefoot support zone;

- stimulating means associated with the insole at the support of the midfoot and of the plantar arch and adapted to apply, during the gait of the patient, a pressure on the midfoot and on the plantar arch of the patient's foot, a transversal stepped protrusion associated with the insole at the support of the forefoot, the transversal stepped protrusion being adapted to open/close the metatarsal heads during the gait of the patient to assist the blood reflux.

Advantageously, actuating means are provided associated with the insole at the rearfoot support zone, said actuating means receiving a pressure from the foot actuates the stimulating means, such that during the next phase of plantar support, the plantar arch and the midfoot, starting from a not pressed condition, are subject to an action by the stimulating means, this action compressing the venous sponge of the foot for stimulating the blood reflux towards the leg of the blood accumulated in the venous sponge, the blood reflux being assisted by the action of the transversal stepped protrusion that opens progressively the metatarsi, previously closed, according to a fan-like configuration.

Owing to the configuration of the insole according to the invention, moreover, during the support phase of the forefoot, the actuating means are not more forced by the rearfoot support zone, such that the stimulating means reduce the pressure on the midfoot and on the plantar zone, the transversal stepped protrusion maintaining the action on the metatarsal bones that remain open according to a fan-like configuration assisting the blood reflux.

Furthermore, when detaching the foot from the ground, the actuating means continue not to be forced by the rearfoot support zone, such that the stimulating means stop, or reduce, the pressure on the midfoot and on the plantar zone, and contemporaneously the reaction is reduced or ends of the transversal stepped protrusion, so that the metatarsal bones close again approaching to each other, blocking again the blood reflux.

Advantageously, the insole comprises at least a first and a second layer overlapped to each other, the actuating means and the stimulating means being arranged between the first and the second layer. Advantageously, the second layer extends above the first layer between the rearfoot support zone and the zone of metatarsal heads at which the transversal stepped protrusion is provided .

Advantageously, the actuating means are arranged in a housing made at the surface of the second layer that in use faces towards the first layer.

Advantageously, the actuating means and the stimulating means comprise respectively: a first reservoir of flexible material arranged at the rearfoot support zone, a second reservoir also of flexible material arranged at the midfoot and plantar arch support zone, the second reservoir being in fluid dynamic connection with the first reservoir, the first and the second reservoir being selectively inflated by a fluid circulating between them responsive to the position of the load of the patient's body on the foot during the gait. Advantageously, the first and the second reservoir are connected by a duct. Alternatively, the first and the second reservoir are connected by a first duct having a check valve adapted to cause the fluid to move from the first to the second reservoir and to prevent backflow, and at least one second duct having a check valve adapted to cause the fluid to move from the second to the first reservoir and to prevent backflow.

Advantageously, the fluid is selected from the group comprised of: a gas; a liquid.

Advantageously, the actuating means and the stimulating means are associated with at least one sensor adapted to measure a value of pressure on the actuating means and to transmit it to a control unit adapted to actuates selectively the stimulating means responsive to value of the data of pressure.

Advantageously, when the pressure increases owing to patient's load at the rearfoot support zone, the sensor operates the stimulating means.

Advantageously, the second layer is made of thermoplastic materials, such that it moulds directly on the patient's foot in order to fit perfectly to the shape thereof.

Advantageously, the first layer is made of expanded plastic material.

In an exemplary embodiment of the invention, the actuating means comprises a cylinder/piston arranged at the rearfoot support zone and the stimulating means comprise a cylinder/piston arranged at the plantar arch and midfoot support zone, the cylinders being connected to each other by a duct, such that by squeezing one of them, the other moves up and vice- versa. This way an effect is obtained similar to what described above, in the four phases of rearfoot support, plantar support, forefoot support and detaching the foot from the ground. In a further exemplary embodiment of the invention, the actuating means comprises a plate arranged at the rearfoot support zone and the stimulating means comprise a plate arranged at the plantar arch and midfoot support zone, the cylinders being connected to each other by an arm hinged to said insole, such that by squeezing one of them, the other moves up and vice- versa, obtaining the same effect in the said four steps .

Brief description of the drawings. The invention will be made clearer with the following description of an exemplary embodiment thereof, exemplifying but not limitative, with reference to the attached drawings wherein:

Figure 1 shows a perspective view of a plantar orthosis for treatment of lower limb diseases, in particular, chronic venous insufficiency, according to the invention;

Figure 2 shows a foot in a phase of rearfoot support; - Figure 3 shows in detail an exploded perspective view of a first exemplary embodiment of the orthosis of figure 1;

Figure 4 shows a perspective partially cross sectional view of the orthosis of figure 3 in the rearfoot support phase;

Figures from 5 to 8 show diagrairanatically the phenomena that occur on the plantar orthosis of figure

1 and on the patient's foot, in the four phases of rearfoot support, plantar support, forefoot support and detaching the foot from the ground;

Figure 9 shows a view similar to figure 4, but in the forefoot support phase;

Figures 10 and 11 show a forefoot respectively in a configuration with metatarsal heads closed and open;

Figure 12 shows a perspective view of an exemplary embodiment of the orthosis of figure 1;

Figures 13 and 14 show perspective partially cross sectional views of the plantar orthosis according to figure 12 in two different working configurations;

Figures 15 and 16 show perspective partially cross sectional views of an exemplary embodiment of the plantar orthosis according to figure 12 in two different working configurations; - Figure 17 shows a further exemplary embodiment of the actuating means and of the stimulating means of the orthosis according to the invention.

Description of preferred exemplary embodiments. With reference to figures 1 and 2, a plantar orthosis 1, according to the invention, for treatment of lower limb diseases of a patient, in particular, owing to venous insufficiency, comprises an insole 2 having a rearfoot support zone 41, a midfoot support zone 42 and a transversal stepped protrusion 43. According to the present invention, the insole is made so that, during the gait of a patient, the rearfoot support zone 41, receiving a pressure from the patient's foot in the rearfoot support phase 51, enlarges the midfoot support zone at the plantar arch 52 producing a pressure on the latter. This action combines with the action of the transversal stepped protrusion 43, which is adapted to cause opening/closing the metatarsal heads of the forefoot 53, to assist the blood reflux. Owing to this, a gait with the plantar orthosis 1 as above described allows to obtain the results described hereinafter.

To this purpose, in a first exemplary embodiment of the invention shown in an exploded view in figure 3, the insole 2 can comprise a first layer 3, for example of foam material of polyethylene copolymers, and a second layer 4, for example of linear polyester on a two weft textile base. Second layer 4 is used for forming two reservoirs 11 and 12 united by a duct 13. More precisely, the first reservoir 11 is arranged in the rearfoot zone 41 of the insole, whereas the second reservoir 12 is arranged in the midfoot and plantar arch zone 42. As shown in figure 3, the reservoirs 11 and 12 can be arranged in a housing 6 with complementary shape, for example made at the surface 4b of the second layer 4 that in use faces towards first layer 3.

Reservoir 11 can have, for example, a substantially elliptical shape, corresponding substantially to the shape of the rearfoot support zone 51 (figure 2) , whereas reservoir 12 has an elongated shape and is arranged transversally to the foot. The shape, the size and the position of reservoir 12 can be obtained according to the anatomical shape of the patient's foot, and are adapted to apply a correct action, as hereinafter described, in the plantar arch and midfoot support zone 52.

As shown in figure 4, the reservoirs 11 and 12 are selectively filled with a fluid 20, for example air or water, which inflates either reservoir 11, now or reservoir 12, according to the position of the load of the patient's body on the foot 50. More in detail, as diagrammatically shown in figure 4, and with reference also o the position of the foot of figure 2, when the patient rests on the rearfoot zone 51 the pressure of the body weight on zone 4 squeezes reservoir 11 causing a movement of the fluid 20 towards reservoir 12 (see also figure 5), which is inflated and raises zone 42 that is located at the midfoot and plantar arch 52 of the patient's foot. Zone 42 remains inflated, owing to the fluid present in reservoir 12, until the patient does not raise rearfoot 51 from zone 41.

Normally the action of second reservoir 12 depends on the variation of volume subsequent to the interactions with first reservoir 11, according to the distribution of the loads between the two reservoirs, in turn according to the weight of the patient, the geometry of the reservoirs, the type of fluid, the static pressure of the fluid, the conformation of the shoe. The choice of the size of the duct 13, furthermore, is adapted to change the viscoelastic behaviour of reservoirs 11 and 12.

In an alternative exemplary embodiment not shown in the figures but easily implemented by a skilled person, the first and the second reservoir 11 and 12 are connected by a first duct having a check valve adapted to cause the fluid to move from the first to the second reservoir and to prevent backflow, and at least one second duct having a check valve adapted to cause the fluid to move from the second to the first reservoir and to prevent backflow. In more detail, with reference to figure 5, during the phase of rearfoot support, the load acting on rearfoot 51 squeezes the zone 41 compressing reservoir 11, having essentially a storage function, transferring part of the fluid in it contained to reservoir 12. More in detail, during this phase reservoir 12 is pressurized in order to cause zone 42 to inflate by applying a first triggering action in the zone 52 of the plantar arch and midfoot support of the foot 50 of the patient. This first stimulus is in any case only partial, since the load of the weight of the patient is born about completely from the rearfoot 51.

After the rearfoot support phase, a successive phase follows diagrammatically shown in figure 6. In this configuration, in which the foot is completely supported by the ground, distributing the load between rearfoot 51, midfoot 52 and forefoot 53. The zone 41 with reservoir 11 continues to be flat, maintaining reservoir 12 of zone 42 inflated, which is thereafter raised by applying a stimulating action on zone 52 of the midfoot and of the plantar arch, thus compressing the venous sponge and stimulating the blood reflux towards the leg of the blood accumulated in the venous sponge. This blood reflux is assisted by the action of the transversal stepped protrusion 43 that, after receiving part of the load on the foot, reacts on the forefoot 53 by opening of metatarsal bones, which were previously closed at an angle αl (figure 10) , to a fan-like configuration according to an angle α2 (figure 11) .

After the phase of rearfoot support a step of forefoot support 53 follows, during which the load acting on rearfoot 51 is low, or zero (figure 7) . During this step the load dos not act any more on the zone 41 with reservoir 11, and the pressure of the midfoot on zone 42 assists pumping the fluid from reservoir 12 to reservoir 11 (see also figure 9). As shown in figure 7 the action of zone 42 is thereafter lower, or even stopped, and then the compression of the venous sponge is also reduced, whereas the action of the transversal stepped protrusion 43 remains active, which assists still a residual blood reflux from the venous sponge of the foot towards the leg.

Finally, during the last phase of the gait, shown in figure 8, there is the detachment of foot 50 from the ground. During this phase, reservoirs 11 and 12 are subject to a minimum load or are unloaded, and therefore the compression of the venous sponge is reduced further with respect to the previous step, or it ends completely, and the blood flow supplies blood to the venous sponge. The absence of load reduces, or dtops, also the reaction of the transversal stepped protrusion 43. Therefore, the metatarsal bones 55 close again approaching to each other (figure 10) creating again an angle αl, with αl< α2, avoiding the blood reflux.

Therefore, with this repeated action, which is carried out with the gait cycles, a compromised venous pumping action owing to venous insufficiency is recovered.

In an alternative exemplary embodiment, as diagrammatically shown in figures from 12 to the 14, the actuating means comprises a sensor of force 21 arranged at the rearfoot support zone 41 and the stimulating means comprise an actuator 22 arranged at the plantar arch and midfoot support zone 42. In particular, the sensor of force 21 detects a value of pressure at the insole 2 and sends it to a control unit 25 that operates the actuator 22, for example of electromechanical type, responsive to the value of pressure. More in detail, one of the possible mode of operation is the following: when the pressure increases owing to patient's load at the zone 41, control unit 25 operates actuator 22 (figure 13) , which raises stimulation zone 42 of the plantar arch. Instead, without force rearfoot 51 support, the control unit 25 discharges actuator 22 (figure 14), which lowers plantar arch stimulation zone 42. Then, even if in a different way with respect to figures 3 and 4, the system is capable to execute all the steps of figures from 5 to 8. In a further alternative exemplary embodiment, diagrammatically shown in figures from 15 to 16, the actuating means comprises a cylinder/piston 31 arranged at the rearfoot support zone 41 and the stimulating means comprise a cylinder/piston 32 arranged at zone 42, set between plantar arch and the midfoot. The two cylinders 31 and 32 are connected by a duct 33, such that by squeezing one of them, the other moves up and vice-versa. In particular, the piston 31 is pressed during the action of the heel in the rearfoot support zone 41, lifting piston 32 (figure 17) . Instead, without force in rearfoot support zone 41 and in midfoot zone 42, like during the situations of figures 7 and 8, cylinder/piston 31 is raised (figure 16) . Also here, even if differently from figures 3 and 4, the system is capable of executing all the steps of figures from 5 to 8.

Finally, in a further exemplary embodiment, diagrammatically shown in figure 17, the stimulating means comprises a plate 61 arranged at the rearfoot support zone (not shown in the figure) and a plate 62 arranged at the zone set between the plantar arch and the midfoot. The two plates 61 and 62 are connected by an arm 63, hinged at point 65 to a support 64 integral to the insole, creating substantially a first type lever. This way, by squeezing one of the two plates, the other moves up and vice-versa. In particular, starting from the position indicated as dotted line, the plate 61 is pressed during the action of the heel in the rearfoot support zone, causing plate 62 to raise (position indicated as continuous line) , which pushes under the plantar arch and the midfoot, as shown by analogy to figures 5 and 6. Instead, without force in the rearfoot support zone and in the midfoot zone, like figures 7 and 8, the plate 31 is raised (shown with dotted line) . Also here, even if different from figures 3 and 4, the system is capable of carrying out all the steps of figures from 5 to 8.

The foregoing description of a specific embodiment will so fully reveal the invention according to the conceptual point of view, so that others, by applying current knowledge, will be able to modify and/or adapt for various applications such an embodiment without further research and without parting from the invention, and it is therefore to be understood that such adaptations and modifications will have to be considered as equivalent to the specific embodiment. The means and the materials to realise the different functions described herein could have a different nature without, for this reason, departing from the field of the invention. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.

Claims

1. Plantar orthesis for treatment of lower limb diseases, in particular, venous insufficiency, said plantar orthosis being characterised in that it comprises:

- an insole adapted to be arranged in a shoe and to support the gait of a patient, said insole having a rearfoot support zone, a midfoot support zone and a forefoot support zone; - stimulating means associated with said insole at said midfoot support zone and/or the plantar arch zone and adapted to apply, during the gait of the patient, a pressure at the midfoot and/or the plantar arch, - a transversal stepped protrusion associated with said insole at said forefoot support zone, said transversal stepped protrusion being adapted to cause the opening/closing of foot metatarsal heads during the gait of the patient to assist a blood reflux.

2. Plantar orthesis, according to claim 1, wherein actuating means are provided associated with said insole at said rearfoot support zone, said actuating means, in the rearfoot support phase of the patient's foot, when receiving a pressure from the foot, actuates said stimulating means, such that during the next phase of plantar support, the plantar arch and the midfoot, starting from a not pressed condition, are subject to an action by said stimulating means, said action compressing the venous sponge of the foot for stimulating the blood reflux towards the leg of the blood accumulated in accumulated in the venous sponge, this blood reflux being assisted by the action of the transversal stepped protrusion that, starting from the plantar support phase, causes progressively the metatarsal bones, previously closed, to reach a fan-like configuration .

3. Plantar orthesis, according to claim 1, wherein during the support phase of the forefoot, said actuating means are not forced by the rearfoot support zone, said stimulating means reducing the pressure at the midfoot and/or the plantar arch, said transversal stepped protrusion maintaining the action on the metatarsal bones that remain open according to a fan-like configuration assisting blood reflux.

4. Plantar orthesis, according to claim 1, wherein when detaching the foot from the ground, said actuating means continue not to be forced by the rearfoot support zone, said stimulating means stopping, or reducing, the pressure on the midfoot and on the plantar zone and, always when detaching from the ground, the reaction of the transversal stepped protrusion is reduced or ends, such that the metatarsal bones close again approaching to each other blocking again the blood reflux.

5. Plantar orthesis, according to claim 1, wherein said insole comprises at least a first and a second layer overlapped to each other, said actuating means and said stimulating means being arranged between said first and said second layer.

6. Plantar orthesis, according to claim 5, wherein said second layer extends above said first layer between said rearfoot support zone and the zone of metatarsal heads, at which said transversal stepped protrusion is provided.

7. Plantar orthesis, according to claim 5, wherein said actuating means are arranged in a housing made at the surface of said second layer that in use faces towards said first layer.

8. Plantar orthesis, according to claim 1, wherein said actuating means and said stimulating means comprise respectively: - a first reservoir of flexible material arranged at said rearfoot support zone,

- a second reservoir also of flexible material arranged between said midfoot and said plantar arch, said second reservoir being in fluid dynamic connection with said first reservoir, said first and said second reservoir being selectively inflated by a fluid circulating between them responsive to the position of the load of the patient's body on the foot during the gait.

9. Plantar orthesis, according to claim 8, wherein said first and said second reservoir are connected by a duct of predetermined cross section, chosen in order to give a viscoelastic behaviour to said second reservoir.

10. Plantar orthesis, according to claim 8, wherein said first and said second reservoir are connected by at least one first duct having a check valve adapted to allow the movement of said fluid from said first to said second reservoir and to prevent backflow, and at least one second duct having a check valve adapted to allow the movement of said fluid from said second to said first reservoir and to prevent backflow.

11. Plantar orthesis, according to claim 1, wherein said actuating means and said stimulating means are associated with at least one sensor adapted to measure a value of pressure on said actuating means and to transmit it to a control unit adapted to actuate selectively said stimulating means responsive to value of said value of pressure.

12. Plantar orthesis, according to claim 5, wherein said first layer is of foam material, in particular, based on copolymers of polyethylene, and said second layer is obtained by a plastic flexible material compact on a textile base, in particular, in linear polyester on a two weft textile base.

13. Plantar orthesis, according to claim 1, wherein said second layer is made of thermoplastic materials, such that it moulds directly on the patient's foot in order to fit perfectly to the shape thereof.

14. Plantar orthesis, according to claim 1, wherein said actuating means comprises a cylinder/piston arranged at the rearfoot support zone and said stimulating means comprises a cylinder/piston arranged at the plantar arch and midfoot support zone, said cylinders being connected to each other by at least one duct, such that by squeezing one of them, the other moves up and vice-versa

15. Plantar orthesis, according to claim 1, wherein said actuating means comprises a plate arranged at the rearfoot support zone and said stimulating means comprise a plate arranged at the plantar arch and midfoot support zone, said plates being connected to each other by an arm hinged to said insole, such that by squeezing one of them, the other moves up and vice-versa.