WO2009125347A2

WO2009125347A2 - Robotic device for lower limb functionality recovery in bed-bound post-stroke patients

Info

Publication number: WO2009125347A2
Application number: PCT/IB2009/051466
Authority: WO
Inventors: Silvestro Micera; Giuseppe Galardi; Maria Chiara Carrozza; Je Hyung Jung; Vito Monaco; Olivier Lefebvre; Giovanna Macri'; Sergio Bagnato
Original assignee: Scuola Superiore Di Studi Universitari E Di Perfezionamento Sant'anna; Fondazione Istituto San Raffaele -G.Giglio Di Cefalu'
Priority date: 2008-04-09
Filing date: 2009-04-07
Publication date: 2009-10-15
Also published as: ITFI20080071A1; EP2306957A2; WO2009125347A3

Abstract

Robotic device for regaining function in the lower limbs of patients confined to bed in the acute post-stroke phase, which comprises a device for supporting and restraining the patient when the latter is lying down (11),- b) a system (14) which provides for movement of the limbs such that the articular travel of the hip, knee and ankle is.similar to that performed when walking, according to the speed. The device further comprises: c) a system of walls (25), suitable for limiting the movements of abduction and adduction of the knees; d) a device (27), capable of preventing the hyperextension of the knees during the therapy cycle. Finally, the device is designed to hold screens and acoustic indicators, to send cognitive stimuli to the patients with the aim of encouraging proper neuromotorial re-education.

Description

TITLE

ROBOTIC DEVICE FOR LOWER LIMB FUNCTIONALITY RECOVERY IN BED- BOUND POST-STROKE PATIENTS

DESCRIPTION The present invention relates to the field of machinery for regaining motor function in neuropathological patients and, more particularly, it has as an object a robotic device for lower limbs functionality recovery of patients confined to bed during the acute phase, subsequent to a cerebrovascular event such as a stroke.

As is known a stroke causes, in the majority of victims, significant motor disabilities. Mostly, in these patients, motor dysfunctions associated with deambulation occur as a result both of the lesions caused by the accident and problems of a muscular and skeletal and cardiovascular nature consequent to the lack of motor activity. The typical motor dysfunctions associated with deambulation include muscle weakness, muscle paralysis, poor motor control and soft tissue contractures. After a stroke the nervous system passes from the acute phase of diaschisis, wherein there is a reduction in neuronal metabolism and in the cerebral haematic flow caused by the lesions arising from the accident, to a subsequent phase of continuous reconstruction, wherein there is cerebral reorganisation in response to the external stimuli linked to the activities and to the behaviour of the patient. Unnatural stimuli due, for example, to muscle hyposthenia, to disorders of the capacity for response to the same stimuli, to incorrect administration of rehabilitation therapy and to the loss of motor schemas invalidate the proper medulla reorganisation and, therefore, full recovery of motor ability.

Conventional rehabilitation currently provides, during the acute phase of the pathology, for administration of passive manipulation, suitable for avoiding complications correlated to lack of mobility, improving control of the torso and training postural transitions. These exercises play an important role in the general wellbeing of the patient yet are not useful in the same way as regards neuromotor re-education in that they are not designed specifically for this purpose. From what has been said it is clear that it is necessary to administer rehabilitation therapy as soon as possible after an accident, that is to say already in the phase wherein the patients, albeit confined to bed in that not yet capable of maintaining a safe erect posture, are in the phase wherein the central nervous system is reforming the neural paths with the aim of regaining the abilities lost. This therapy must be capable of sending alternate and bilateral stimuli to the central nervous system that are as natural as possible, in such a way as to direct remodelling of the areas of the brain towards recovery of such motor abilities as before the accident.

Devices are already known which allow performance of re-education of the lower limbs of patients confined to bed in the acute post-stroke phase. They mostly comprise a first part for the supporting and restraining of the patient when lying down and a second part for movement of the legs of the patient which provides, for each leg, a pedal whereon the sole of the patient's foot rests and means for moving the pedal on a plane parallel to the sagittal plane of the patient. Examples of these devices are shown, among other things, in the patents US5901581 , US6685658, FR2860975, and in the patent applications JP2003199799 and WO2006094018.

However the devices known to date have a series of aspects which do not make them optimal for their purpose.

A first aspect is linked to the fact that the movement applied to the legs does not follow a movement similar to that of real deambulation but instead a simple movement of the legs according to circular trajectories, without any control of the pedal and, consequently, of the angular travel of the ankle. Another aspect which makes devices of the known type inadequate is linked to the fact that they reduce the risk of hyperextension of the knee by direct manipulation of the thigh, therefore supplying unnatural sensory information and preventing the individual from feeling active during the movement control phase.

A further aspect which makes some of the known devices inadequate is inherent in the fact that they require the patient to be moved from the hospital bed to a support surface integrated with the same device or movement of the patient towards a device which requires, even if by means of a support, an erect position. This entails the need for additional staff for moving the patient, the detaching of any monitoring devices associated with the patient and a greater waste of time. Furthermore, another aspect which makes devices of the known type inadequate is linked to the fact that their structure and the types of movement mechanisms used are complex, which makes them expensive and difficult to use and maintain.

The object of the present invention is that of overcoming the limits of the devices of a known type for re-education of the lower limbs of patients confined to bed in the acute post-stroke phase, developing a device which allows re-education of the lower limbs via a movement similar to those produced during walking without phenomena of adduction and abduction of the knees or hyperextension of the same.

At the same time an object of the invention is that of providing a device for the re-education of the lower limbs of patients confined to bed in the acute post-stroke phase without them having necessarily to be moved onto a dedicated re-education device.

Another object of the invention is to provide a device for the re-education of the lower limbs of patients confined to bed in the acute post-stroke phase which is structurally simple and easy to use.

These and other objects, which will be made clearer further on, are achieved with a robotic device for the regaining of the function of the lower limbs of patients confined to bed in the acute post-stroke phase, which comprises a first part for the supporting and restraining of the patient when lying down and a second part for movement of the legs of the patient. The latter provides, for each leg, a pedal whereon the sole of the patient's foot rests and means for moving the pedal on a plane parallel to the sagittal plane of the patient. The device is characterised in that the pedal moving, controlled electronically, comprise means of independent rotation of the pedal around an axis orthogonal to the sagittal plane. The second part, by combining the movement of the pedals on the respective planes parallel to the sagittal plane with rotation of the same pedals on said planes, allows the achievement of a resulting leg movement similar to that which can be achieved during normal deambulation. The device further comprises:

- a third part, for preventing movements of abduction and adduction of the knees, which comprises, for each leg, a pair of vertical walls provided on opposite sides of each knee, capable of preventing movement thereof in the frontal plane, - a fourth part, for preventing the hyperextension of the knees during the deambulatory movement, which comprises two supports, one for each knee, and means of kinematic connection of the two supports which define a maximum distance between the knees. The kinematic connection means apply, when the knees are at the maximum distance and the upper knee support moves upwards, an action of upward movement to the lower knee support.

Further characteristics, and advantages, of the device according to the present invention will be made clearer by the following description of one of its embodiments, given by way of a non-limiting example with reference to the accompanying drawings in which:

- Fig. 1 is a three-quarter axonometric view from above of a device according to the invention associated with a hospital bed; - Fig. 2 shows the same view of Fig. 1 , with some parts of the device removed to allow a clearer view of the components;

- Fig. 3 shows a front view of the part of the device relating to the means for moving the legs;

- Fig. 4 shows the detail of the pedal of the device according to the invention; - Fig. 5 shows a front axonometric view of the part of device relating to means for preventing movements of abduction and adduction of the knees;

- Fig. 6 shows a front axonometric view of the part of device relating to means for preventing the hyperextension of the knees during the deambulatory movement.

Referring to the above mentioned drawings, reference numeral 1 1 denotes a first part of the device according to the invention, suitable for supporting and restraining the patient when lying down. More particularly this first part 11 comprises

(see Fig. 7) a frame 12 for the support of the pelvis, to be placed adjacent to the terminal end of the hospital bed 13. This frame 12 is composed of a platform 12a supported by three legs 12b whose feet 12c are of the height adjustable type. The dimensions of the platform 12a are such as to allow the resting of only the pelvis of the patient.

At the middle line of the platform 12a, from a frontal peripheral zone of the latter, a contact surface 12d develops upwards, against which the interior of the groin area of the patient abuts, thus preventing forward movement thereof. From the side panels of the platform 12a a belt 12e extends which surrounds and restrains the pelvis of the patient.

Frontally to the first part 1 1 there is a second part of the device, generally denoted by reference numeral 14, suitable for moving the legs of the patient.

The second part 14 comprises two mirror sections 14a and 14b, one for each leg. Each section is equipped with a pedal 15 whereon the sole of the patient's foot rests, and means 16 for movement of the pedal 15 on a plane parallel to the sagittal plane of the patient and around an axis Z orthogonal to the abovementioned sagittal plane.

The pedal 15 is formed by an L-shaped bracket such as to allow partial resting of the heel bone (the lower portion of the bracket whereon the heel bone rests is not shown). Tapes in Velcro® (not shown in the drawings) allow the foot to be restrained to the pedal.

According to the invention the means 16 for moving the pedal are controlled electronically and allow the achievement of a movement of the legs similar to that which can be achieved during normal deambulation, i.e. the reproduction of articular trajectories similar to those achieved during walking. According to an advantageous embodiment these pedal moving means 16 comprise means for translation of the pedal 15 in two directions orthogonal one to the other and lying on a plane parallel to the sagittal plane, and means 17 for rotation around the abovementioned axis Z orthogonal to the sagittal plane. In practice the moving means 16 constitute an electronically controlled orthogonal manipulator and the pedal is keyed thereto so as to create a system with three degrees of freedom.

In the embodiment described the two co-planar translations applied by the abovementioned pedal moving means 16 to the pedal 15 take place in a vertical direction and a horizontal direction.

As shown more particularly in Figs. 3 and 4, the pedal moving means 16 comprise a first actuator 17 suitable for allowing rotation around the axis Z of the relative pedal 15 on a support slider 18.

In the present embodiment the vertical translation means, generally denoted by

19, comprise a vertical guide 19a, whereon the slider 18 is positioned slidingly through interposition of a first prismatic joint 18a, and a first electric motor 19b, positioned at the lower end of this vertical guide 19a. The first electric motor 19b is kinematically connected to the slider 18 to allow translation thereof on the vertical guide 19a.

The horizontal translation means, generally denoted by 20, comprise, in this embodiment, a horizontal guide 20a whereon the vertical guide 19a is positioned slidingly through interposition of a second prismatic joint 20b. The horizontal translation means 20 also comprise a second electric motor 20c, placed at one end of the horizontal guide 20a. The motor 20c is kinematically connected to the vertical guide 19a to allow translation thereof on the horizontal guide 20a.

Each section 14a and 14b of the second part 14 of the device is mounted on a base 21 with two columns 22 for supporting for the horizontal guide 20a.

A horizontal sliding bar 23 is formed on the base 21 whereon the lower end of the vertical guide 19a and the support of the first electric motor 19b are positioned. The horizontal sliding bar 23 allows the weight of the vertical guide and of the first electric motor to be supported adequately.

The base 21 is provided with four wheels 21a, pivotable and brakeable if necessary, for moving the device from one bed to the other and appropriately positioning to a bed. The pedal moving means 16 are associated with electronic control and management means, not shown in the drawings, which allow the application on the pedal of the desired combinations of translation and rotational movement, whereby substantially any trajectory on a plane parallel to the sagittal plane can be set. This can be achieved in particular by applying to each pedal a combination of trajectories such as to reproduce a complete and natural deambulatory movement, i.e. trajectories such as to reproduce the articulations of hip, ankle and knee similar to those really occurring during walking according to the required speed.

The device according to the invention also comprises a third part 24 (see Fig. 5), for preventing movements of abduction and adduction of the knees. This third part 24 is positioned between sections 14a and 14b of the second part 14, in a position comprised between the pedals 15 and the pelvis supporting frame 12.

According to the invention the third part 24 comprises, for each leg, a pair of vertical walls 25 which define laterally a space for containing the knee, preventing movement thereof in the frontal plane, i.e. preventing lateral movement thereof. Means 26 are also present for regulation of the distance between the walls 25 of each pair, in such a way as to allow the adaptability to knees of different sizes. These regulation means 26 comprise, in this embodiment, a track 26a whereon the bases 25a of the walls 25 are mounted slidingly, and blocking clamps 26b positioned on these bases and suitable for acting on the rails of the track 26a. Between the walls 25 of each pair telescopic crosspieces 25b are provided for stiffening the overall structure of the third part 24. In this embodiment each wall 25 consists of a rectangular frame 25c supporting a transparent panel 25d which forms the actual lateral containment side. The use of the transparent panel allows staff to observe the movement of the knees between the walls.

Advantageously the outermost side of each pair 25 is divided into a lower portion 25' whereto an upper portion 25" is hinged horizontally and which can be tipped outwards to allow arrangement of the respective leg of the patient between the walls.

The device also comprises a fourth part 27 (see Fig. 6), suitable for preventing hyperextension of the knees during the deambulatory movement. The fourth part 27 comprises two supports 28, one for each knee, and means

29 for kinematic connection of the two supports 28 which define the maximum distance in height between the knees achievable during deambulation. These kinematic connection means 29 apply bending of the extended knee by means of the extension of the bent knee so as to prevent occurrence of the risk of knee hyperextension. More particularly, when the knees are at the maximum distance and the upper knee support moves upwards, the kinematic connection means 29 apply an action of upward movement to the lower knee support.

Referring to the embodiment described, each support 28 is in the form of a casing which envelops the knee and allows bending thereof. On the two side panels of the casing two elements 28a for reducing friction are positioned, such as for example small freely rotating balls, suitable for coming into contact with the walls 25.

In this configuration the kinematic connection means 29 comprise a cable 29a whose ends are attached on the respective upper parts of the casings 28. The cable is passed via two through elements 29b, such as two pulleys, positioned at the top of the innermost walls of the pairs of walls 25. Pulleys 29b allow the cable sliding direction to be reversed.

A final characteristic of the device according to the present invention relates to the presence of means, generally denoted with the numeral 30 in Figure 1 , dedicated to sending cognitive stimuli during the rehabilitation therapy, such as for example screens and acoustic indicators. These are associated with electronic means of management and control of the movement and their purpose is to report, via sounds and/or graphic elements, indications concerning the motor performance achieved during the therapy. In particular, these means of cognitive stimulation 30 provide information correlated to the cyclical nature of the step, indicating, for example, which of the two legs is forward or how close the trajectory of the articular joints of the patient is to the desired one. The device is thus capable of simultaneously administering manipulation of the limbs and cognitive stimuli in accordance with the step cycle, increasing, in fact, the efficacy of the rehabilitation action compared to other re-education devices. The operation of the device is the following. The device is brought frontally to the bed of the patient with the frame 12 positioned adjacent to the end of the bed. The height of the pelvis supporting platform is adjusted in accordance to the dimensions of the bed. Subsequently the pelvis supporting platform, the walls for preventing adduction and abduction of the knee and, finally, the two orthogonal manipulators 16, which allow movement of the pedal, are laid at the bed, in this order. The presence of lockable wheels allows the position of the manipulators to be fixed and render them immobile during the therapy administration step.

The patient, who has previously put on the knee casings 28, is moved forwards, bringing the pelvis onto the support surface 12a, with the internal groin area abutting against the contact surface 12d. The pelvis is then blocked by means of the belt 12e. The legs are inserted between the respective walls 25 and the supports 28 are fixed to the knees, passing the cable 29a in the pulleys 29b. Preliminarily the upper portions 25" of the outermost walls are tipped outwards to allow the positioning of the legs and the operations of attaching of the supports 28 of the knees. The feet are attached by means of Velcro® tapes to the respective pedals 15. Then the walls portions 25" are raised and the distance between the walls relative to each leg is appropriately adjusted in such a way that the elements for facilitating sliding 28a of the supports 28 are in contact with the same walls. The device is now ready for re-education operation. The electronic means of management and control are brought into operation, with consequent actuation of the electric motors 17, 19a and 20a and the required trajectory is applied to pedals 15.

The electronic management of the motors also allows setting of the most appropriate deambulation speed.

The electronic management and control means also allow trajectories different from that of classic deambulation to be set, useful for other types of re-education exercises.

The invention described in this way fulfils the purposes intended for it. In fact a robotic device has been provided for regaining the functionality of the lower limbs of patients confined to bed in the acute post-stroke phase which allows the lower limbs to be made to perform trajectories on a plane parallel to the sagittal plane similar to those achieved during deambulation. These trajectories are achieved without there being risks of hyperextension, abduction or adduction of the knees, to the full advantage of the restoring of correct movement. The device proposed is in practice capable of moving the legs, leaving the patient the sensation of being able to control the critical phases of the step cycle, including hyperextension of the knee, reducing interference between manipulator and leg to a minimum.

The particular structure allows positioning of the device directly at the feet of the bed, allowing use thereof without the need for extensive moving of the patient but instead simply performing a small translation of the patient on the bed.

Moreover the components of the device are formed by structurally simple elements which inevitably leads to low production costs and to easier maintenance.

Finally, the combination of rehabilitation therapy associated with cognitive stimuli according to the step cycle represents an important aspect in relation to what is contained in literature in that it is proposed to perform motor capacity re-education, improving control of the limb from the neuromotor viewpoint, since it increases the efficacy of the therapeutic action, encouraging the recovery of neural reorganisation.

The device designed in this way may undergo a number of modifications and variants, all coming within the sphere of the same inventive concept. Moreover all the details may be replaced by other technically equivalent elements without thereby departing from the scope of the invention. In practice the materials used, provided they are compatible with the specific use, as well as the dimensions, may be any type according to needs and the state of the art.

Where the features and techniques mentioned in any claim are followed by reference signs, the latter have been included, by way of an example, for the sole purpose of increasing the intelligibility of the claims and consequently have no limiting effect on the interpretation of each element that they identify.

Claims

1. Robotic device for lower limb functionality by recovery in patients confined to bed in the acute post-stroke phase, comprising a first part (11) for supporting and restraining of the patient when lying down and a second part (14) for moving the legs of the patient which comprises, for each leg, a pedal (15) whereon the sole of the patient's foot rests and means (16) for moving said pedal (15) on a plane parallel to the sagittal plane of the patient, characterised in that said pedal moving means (16), controlled electronically, comprise means (17) for independent rotation of said pedal (15) around an axis (Z) orthogonal to the sagittal plane, said second part (14), by combining the movement of the pedals (15) on respective planes parallel to the sagittal plane with the independent rotation of the same pedals on said planes, being capable of achieving a resulting movement leg similar to that which can be achieved during normal deambulation, said device further comprising a third part (24), for prevention of the movements of abduction and adduction of the knees, comprising, for each leg, a pair of vertical walls (25) defining a space there between for containing the knee and suitable for preventing the movement of the knee in the frontal plane, a fourth part (27), for prevention of knee hyperextension during the deambulatory movement, comprising two supports (28), one for each knee, and means (29) of kinematic connection of said two supports (28) which define a maximum distance between the knees, said means of kinematic connection (29) applying, when said knees are at the maximum distance and the upper knee support (28) moves upwards, an action of movement upwards on the lower knee support (28).

2. Device according to claim 1 , characterised in that said pedal moving means (16) comprise means (19, 20) for translation of the pedal (15) in two directions orthogonal one to the other and lying on a plane parallel to the sagittal plane, as well as said means (17) for rotation around said axis (Z) orthogonal to the sagittal plane.

3. Device according to claim 2, characterised in that said second part (14) comprises two mirror sections (14a, 14b), one for each leg, whereon respective pedals (15) are provided, said movement means (16) comprising for each section (14a, 14b) a first actuator (17) suitable for allowing rotation around the axis (Z) of the relevant pedal (15) on a support slider (18), said means (19, 20) for translation of the pedal (15) comprising a vertical guide (19a) to which said slider (18) holding the pedal (15) is slidably connected a first electric motor (19b), positioned on said vertical guide (19a), kinematically connected to said slider (18) to allow translation thereof on the vertical guide (19a), a horizontal guide (20a) to which a slide (20b) is slidably connected, said vertical guide (19a) being attached to said slide (20b), a second electric motor (20c) positioned on said horizontal guide (20a), kinematically connected to said slide (20b) to allow the translation thereof on the horizontal guide (20a).

4. Device according to claim 3, characterised in that each section (14a, 14b) of said second part (14) comprises a base (21) with columns (22) raising therefrom for supporting said horizontal guide (20a), a horizontal sliding bar (23) being further provided on said base, the lower end of said vertical guide (19a) and the support of the first electric motor (19b) being slidably connected to said bar (23).

5. Device according to any one of the previous claims, characterised in that it comprises means (26) for adjusting the distance between the walls (25) of each pair, in such a way as to allow adaptability to knees of different sizes.

6. Device according to claim 5, characterised in that said means (26) for adjusting the distance between the walls (25) comprise a track (26a) whereon the bases (25a) of said walls (25) are mounted slidingly, and locking clamps (26b) positioned on said bases (25a) and suitable for acting on the rails of the track (26a), between the walls (25) of each pair telescopic crosspieces (25b) being provided for stiffening the overall structure of said third part (24).

7. Device according to claim 5 or 6, characterised in that each wall (25) comprises a frame (25c) for supporting a transparent panel (25d).

8. Device according to one of claims 5 to 7, characterised in that the outermost wall of each pair of walls (25) is divided into a lower portion (25') and an upper portion (25") hinged horizontally to the lower portion and outwardly tillable to allow positioning of the respective leg of the patient between the walls (25).

9. Device according to any one of the previous claims, characterised in that said means (29) for kinematic connection of said two supports (28) comprise a cable (29a) whose ends are fixed to said supports (28), said cable being made to pass via at least one through element (29b) positioned above the zone that can be occupied by the knees and capable of allowing reversal of the cable sliding direction from below upwards and vice versa.

10. Device according to claim 9, characterised in that it comprises two through elements (29b) formed by pulleys placed on the top of the innermost walls of each pair of walls (25).

11. Device according to claim 9 or 10, characterised in that on the side panels of each support (28) there are elements for reduction of friction (28a) capable of coming into contact with said walls (25).

12. Device according to one of claims 9 to 11, characterised in that each support (28) comprises a casing for surrounding the knee and allowing bending thereof, the ends of said cable (29a) being attached to the upper portion of said casing.

13. Device according to any one of the previous claims, characterised in that said first part (11) comprises a frame (12) for support of the pelvis of the patient, to be positioned adjacent to the terminal end of the bed (13), said frame (12) comprising in turn a platform (12a) of dimensions such as to allow resting of only the pelvis of the patient, a contact surface (12d), against which the interior of the groin area of the patient abuts, extending upwards from said platform (12a), and a belt (12e) for surrounding and blocking the pelvis of the patient, extending from the side edges of said platform (12a).

14. Device according to claim 13, characterised in that said platform (12a) is supported by legs (12b) whose feet (12c) are of the height adjustable type.

15. Device according to any one of the previous claims, characterised in that it comprises means (30) for sending cognitive stimuli during rehabilitation therapy, associated with electronic means for management and control of the movement of the pedal.

16. Device according to claim 14, characterised in that said means of cognitive stimulation (30) provide screens and/or acoustic indicators reporting information correlated to the cyclical nature of the step.