Abstract:
The invention relates to an apparatus which actively moves the legs of a disabled person in a movement pattern that is similar to physiological walking. The inclination of the standing table can be adjusted between a horizontal and a vertical position as desired. The patient is fixed to the standing table by means of a belt gear. The aim of this kind of rehabilitating locomotion therapy is to activate the locomotion structures in the spinal cord in order to improve the muscular situation in a time optimal manner, to prevent the intensity of spasticity and to improve the circulatory conditions.

Description:
FIELD OF THE INVENTION 
     The invention relates to an apparatus and a process in order to begin a locomotion training of patients with walking impediments in an early phase of rehabilitation. 
     BACKGROUND OF THE INVENTION 
     In incompletely paraplegic patients the possibility has been shown to exist of improving walking ability up to normality by means of an adequate locomotion training. The required therapy at present takes place on a moving belt, where walking is first made possible for the patient by defined weight relief and partially by additional assisting guidance of the legs by physiotherapists (Wickelgren, I. Teaching the spinal cord to walk. Science, 1998, 279, 319-321). This kind of locomotion therapy can of course only be started when there is sufficient stability of the circulation, since the patient has to remain for a long time in an upright position. The required circulatory stability is as a rule not present in the first weeks after the onset of the spinal cord lesion. 
     In the rehabilitation of patients with limited motion of the legs or after orthopedic operations, various driven ortheses are already in use which actively move the legs of recumbent patients. 
     U.S. Pat. No. 5,239,987 (1993) describes such a system. In this apparatus, the legs are guided primarily in that the lower leg is moved relative to the thigh. However, no apparatus exists in which a knee extension with weight loading on the sole of the foot is attained in the extended phase (“standing phase”) of the movement cycle. Hip joint extension is also not present in the said mechanisms. 
     U.S. Pat. No. 4,986,261 (1991) describes an apparatus which also effects a hip joint extension. However, the knee joint is not moved there as in physiological walking. 
     None of the described systems make it possible to move the legs while the inclination of the patient can be simultaneously adjusted. 
     SUMMARY OF THE INVENTION 
     The present invention has as its object to make possible an intensive walking training (activation of the motion centers in the spinal cord) of paraparetic and hemiparetic patients, before they are physically able to take part in a moving belt training, that is, in a still unstable circulatory situation. The possibility is to be provided of steadily bringing the patient&#39;s body closer to the vertical position. The aim of the apparatus according to the invention is to provide a so-called “active standing table” (tilting table) which makes possible the movement of the legs of paraplegic patients in a manner physiologically similar to walking, without the necessity of having them stand upright. 
     This object is attained according to the invention with an active standing table according to the wording of patent claim  1 , and an associated process for the operation of the active standing table according to the wording of patent claim  8 . 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention is described in detail hereinafter using the accompanying drawings. 
     FIG. 1 shows a side view of an active standing table with a patient in a vertical position, 
     FIG. 2 shows an overall view of a first embodiment example of an active standing table in a horizontal position, 
     FIG. 3 shows a mechanism for the setting of the hip extension angle, 
     FIG. 4A shows the knee mechanism of FIG. 2, in a perspective diagram, 
     FIG. 4B shows the knee mechanism of FIG. 2, in a side view, 
     FIG. 5 shows the foot mechanism of FIG. 2, in a perspective diagram, 
     FIG. 6 shows a knee cuff of FIG. 2, in a perspective diagram, 
     FIG. 7 shows an overall view of a second embodiment example of an active standing table in a horizontal position, 
     FIG. 8A shows the knee mechanism of FIG. 7, in a perspective diagram, 
     FIG. 8B shows a top view of the eccentric drive of FIG. 7, 
     FIG. 9 shows the foot mechanism of FIG. 7, in a perspective diagram. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 shows a side view of the active standing table with a patient in a vertical position. A main support serves as a base, as is known for conventional standing tables. It consists of a chassis  1  with rollers  2  and  3  and a height-adjustable frame  6  (e.g., “Super Tilt Table”, Gymna Co., Belgium). The frame  6  can be height-adjusted manually or with a drive (not shown). A joint  7  is mounted on the frame  6  and articulates to the frame  6  a leg portion  8  consisting of two beams and two cross-struts (see FIG.  2 ). The leg portion  8  is further connected by means of a joint  9  to a head portion  10  (frame similar to that of the leg portion  8 ), on which a support surface  11  is situated, consisting of a wooden board with a foam lining. So that the angle of the standing table can be continuously increased toward the vertical during a therapy with the active standing table, the leg portion  8  can be rotated around the joint  7  by a drive  4  and can thus be set at an angle of inclination β 1  in order to be able to carry out a treatment in a known manner at different angles of inclination. The angle of inclination β 1  in the Figure is 90°, which corresponds to a vertical position of the patient. By means of the adjustability of the angle of inclination, patients with unstable blood circulation can be treated already in the recumbent position, and then continuously brought into the vertical position during the therapy, according to their status, the angle of inclination β 1  being gently increased. 
     It is possible to fix an inclination between the leg portion  8  and the head portion  10  with a mechanism  21  for setting the hip extension, a hip extension angle β 2  being thereby defined. A hip extension of the legs can thus be realized during the therapy. When the standing table is situated in a horizontal position, β 2  is always 180°, since the head portion  10  abuts on the frame  6 . If now the angle β 1  is increased, β 2  also is decreased, until the mechanism  21  comes up against its stop and the head portion is likewise brought upward. In this Figure, the angle β 2  is 172°, giving a hip extension value for the patient of 8°; preferred values are about 12°. 
     On the leg portion  8  there are a knee mechanism  13 , with two knee drives  24 , and a foot mechanism  14 . These two mechanisms can be displaced parallel to the leg portion, on two rails  15  which are fastened one on each side of the leg portion  8 , thus permitting the standing table to be suited to the anatomy of different patients. 
     In order to carry out a therapy, the support surface  11  is tilted into the horizontal position and brought, by means of the height adjustment of the main support, to the same height as the hospital bed on which the patient is lying. The patient is then transferred to the support surface  11 , so that his upper body comes to lie on the support surface, and his hip joints on the lower edge of the support surface. A locating belt  16  is then placed around the patient&#39;s hips, and is fastened with fastening bands  17  to eyelets  22  at the upper side of the support surface  11  and with fastening bands  18  to eyelets  23  at the lower side of the support surface. This fastening prevents an up and down movement of the upper body during the therapy. It is provided so as to minimize movements of the trunk, in order to prevent injuries to the possibly still unstable spine. The locating belt  16  corresponds to a belt such as is used in a standard manner for relieving weight in moving belt training of paraplegics (e.g., moving-belt belt article “Walker”, Hamster&#39;s Parachute Service Co., Austria). 
     When the patient is fastened to the support surface, the knee mechanism  13  is displaced on the rails  15  such that the knee drive  24  comes to lie directly under the hollows of the patient&#39;s knees. The knee mechanism is fixed there with securing screws  25 . The foot mechanism  14  is then also displaced, so that an extension (stretching) of the patient&#39;s legs presses footplates  19   a  and  19   b  down as far as a stop (see FIG.  5 ). The foot mechanism  14  is fixed in the correct position with securing screws  26 . Marks present on the rails  15  permit the position of the foot mechanism  13  and knee mechanism  14  to be read off. Using the marks, the settings can easily be reproduced in repeated therapies. 
     Knee cuffs  20  are then fastened around the patient&#39;s knees (see FIG.  6 ). These cuffs are fastened to the knee drives  24 , which thus pull the patient&#39;s knee down or push it up, during the therapy. This respectively effects a stretching or a bending of the legs. In the Figure, the patient&#39;s right leg is shown in the bent state and the left leg in the stretched state. It is to be mentioned that at the beginning of the therapy the two knee drives  24  are retract-ed. The patient can thus be easily transferred to the standing table. A knee drive is first extended when the treatment begins, thus bending a leg. 
     During the locomotion therapy, the knee drives  24  are alternately moved upward and downward, so that the legs of the patient move in a path of motion which is similar to that in normal walking. Thus the sensory input (afferent) from the legs provides information for the spinal locomotion centers in the spinal cord which is similar to that in physiological walking, and excites the locomotion centers to an activation. 
     FIG. 2 shows an overall view of a first embodiment example of an active standing table in a horizontal position. The main support, consisting of a chassis  1  with rollers  2   a ,  2   b ,  3   a  and  3   b , and the height-adjustable frame  6 , can again be seen. The leg portion  8 , a frame consisting of two beams  8 A and  8 A and also two cross struts  8 B and  8 B′, is connected to the frame  6  by means of the joint  7 . The leg portion  8  is further connected by means of the joint  9  to the head portion  10 , on which the support surface  11  is situated. The mechanism  21  for setting the hip extension is situated with the joint  9 . 
     The knee mechanism  13  with the two knee drives  24   a  and  24   b , and a foot mechanism  14 , are situated on the leg portion  8 , and can respectively be displaced on the rails  15   a  and  15   b  parallel to the leg portion  8 . The securing screws  25  and  26  are situated on the leg portion  13  [sic] and on the foot portion  14  [sic], and serve for fastening on the rails  15   a  or  15   b , respectively. 
     Eyelets  22   a ,  22   b ,  23   a  and  23   b  are installed on the support surface  11  for fixing the patient. 
     FIG. 3 shows a side view of the mechanism for setting the hip extension angle. The joint  9  can be seen, with a portion of each of the leg portion  8 , the head portion  10 , the support surface  11  and the rail  15 . An elbow  30  is installed on the leg portion  8 . A limiting screw  31  is situated in a screw thread in this elbow  30 . If the standing table is in the horizontal position (angle of inclination β 1 =0), the head portion  10  is situated on the main support of the tilting table and the angle β 2  is 180°. If now the angle of inclination is increased, the angle β 2  is decreased until the head portion  10  abuts against the screw head  43  of the limiting screw  31 , and the head portion is brought upward. If now the limiting screw  31  is screwed further into the elbow  30 , the angle β 2  becomes correspondingly greater; if screwed out, correspondingly smaller. A pointer  33  shows, on a scale  32 , what hip extension angle for the patient is set with the limiting screw. The hip extension angle corresponds to 180°−β 2 . 
     FIG. 4A shows the knee mechanism  13  of FIG. 2, in a perspective diagram. Rectangular tubes  41   a  and  41   b  (not shown) are situated on each side of a crosspiece  40 . These serve as guides for the knee mechanism  13  on the rails on the leg portion. The crosspiece  40  has two rectangular openings  40 ′ in which the two knee drives  24   a  and  24   b  are situated. These two drives are identical in construction, only one being numbered in the Figure. Bearings  42 ,  43   a  and  43   b  (not shown) are mounted on the crosspiece  40  on the under side, and suspension shafts  44   b  and also  45   b  can freely rotate in them. These suspension shafts are each attached to a baseplate  46   b . Due to this mounting, the knee drives can turn, so that they are moved around the rotation axis of the hip joint by the knee motion of the patient, during a bending or stretching. A motor  47   b  is fastened in the baseplate  46   b , and two guide tubes ( 48   b  or  49   b , not shown) are inserted. Likewise, a guide  50   b  is situated in the baseplate  46   b , and a threaded rod  51   b  is free to turn in it. The construction of the drive by means of a threaded rod is described in detail in FIG. 4B. A respective guide rod  52   b  and  53   b  can be displaced upward and downward in the respective guide tubes  48   b ,  49   b . If now the linear drive moves upward or downward, a plate  54   b  and a knee cushion  55   b  fastened to it are brought upward or downward. The patient&#39;s knee is caused to flex when the knee cushion moves upward, and is pulled into extension when the knee cuff (see FIG. 6) moves downward. The two guide bars  52   b  and  53   b , which are guided in the guide tubes  48   b  and  49   b , provide for the lateral stability of the knee drive, so that the patient&#39;s leg does not incline sideways. The guide tubes  48   b  and  49   b , and also the threaded rod  51   b , are mounted at the upper end in the plate  54   b  and at the lower end in a plate  62   b.    
     A protective sheath  56   a  made of rubber protects the patient from injury on the knee drives. 
     FIG. 4B shows a side view of the knee mechanism  13  of FIG.  2 . The principle of the drive is explained more accurately using this Figure. The crosspiece  40  can be seen, with the baseplate  46  let into the opening  40 ′. The suspension shaft  44  can be seen on the baseplate  46 , and permits a rotation of the knee drive around the axis indicated by the round arrow. The guide tube  48  permits the guide bar  52  to displace the threaded rod  51  through the guide  50 . The motor  47 , which is fixedly mounted in the baseplate  46 , drives a gearwheel  59  mounted on the guide  50  by means of a gearwheel  57  and a V-belt  58 . There is a screw thread in the gearwheel  59 . When now the gearwheel is driven by the motor  47 , the threaded rod  51  moves upward or downward in the baseplate  46 , as indicated by the straight arrow. 
     Respective limit switches  60  and  60 ′ are situated above and below on the baseplate  46 . These serve to indicate the attainment of an end position to a control unit which controls the movement of the drive. If the drive has reached the lowest point, the plate presses with the knee cuff on a contact button  61  and the limit switch  60  signals to the control unit that the motor has to run in the opposite direction. The drive then travels upward until the lower plate presses against a contact button  61 ′, and the limit switch  60 ′ sends the control unit a further signal to change over. 
     FIG. 5 shows the foot mechanism  14  of FIG. 2 in a perspective diagram. A respective rectangular tube  69   a ,  69   b  is fixedly connect ed to the lower side of a T-piece  63 . These serve as guides for the foot mechanism on the rails fastened to the leg portion. The foot mechanism can be secured by the fixing screws  26   a  and  26   b  at the correct place during therapy. A respective footplate  19   a  and  19   b , able to rotate around a bearing at the attachment point to the T-piece, is situated at either side at the upper end of the T-piece  63 . The footplates are of identical construction, all parts appearing symmetrically on both sides. The patient&#39;s feet can be introduced into respective elastic loops  65   a  and  65   b  on the footplates. They are then protected from slipping out by the heel holders  66   a  and  66   b.    
     The footplates  19   a  and  19   b  are each connected to a respective spring  67   a  or  67   b  (not shown). These are tensioned at a respective bolt  68   a  or  68   b  (not shown) when the footplate is pressed downward by the patient (in the direction of the arrow). This produces a pressure on the sole of the patient&#39;s foot in the extended phase of the movement cycle, and simulates a weight force like that experienced in walking. The strength of this weight force can be adjusted by a displacement of the bolt  68   a  into the respective holes  68   a ′. When the angle of inclination of the standing table becomes greater, normally the weight force which acts on the legs also becomes greater. This effect can be compensated and controlled in that the patient is pulled more or less upward with the fastening bands and the locating belt. 
     FIG. 6 shows a perspective diagram of a knee cuff of FIG. 2. A plate  70  is securely mounted on the upper ends of the threaded rod  49  and of the guide bars  54  and  55 . A yoke  71  is attached to this plate, and a knee cushion  53  can be fastened to the yoke by two clip mechanisms  72  and  72 ′. This knee cushion  53  is of foam material covered with plastic. The clip mechanism holds the knee cushion firmly enough to effect an extension of the knee when the knee drive is pulled downward. The connection is however released when the patient&#39;s knee cannot be extended for any reason in a faulty manipulation. This serves as a load protection for the patient&#39;s legs and protects him from injury. The clip mechanism releases the knee cushion at load forces or tensile forces of 150-200 N, preferably of 180 N. A knee cuff consisting of two hook-and-loop fastener bands  73  and  73 ′ is fastened to the knee cushion  53  and permits the patient&#39;s knee to be fastened to the knee cushion, in that the bands are mounted on the hook-and-loop strips  74 . The two bands are fastened to the knee such that the patient&#39;s kneecap is situated between the bands and is not subjected to pressure by them when the leg is extended. 
     FIG. 7 shows an overall view of a second embodiment example of an active standing table in a horizontal position. The basic construction is identical to that of the first embodiment example. Differently from this, in the present training apparatus the patient&#39;s legs are driven by an eccentric drive  81 , described in detail in FIG. 8, via a cable  80 , and not with a linear drive. A knee portion  82  and a foot portion  83  can be displaced on the rails  15   a  and  15   b  and thus matched to the leg length of the patient. 
     FIG. 8 shows the knee mechanism of FIG. 7 in a perspective diagram. It consists of an eccentric drive  81 , cables  80   a  and  80   b  (nylon cables), and also the knee portion  82 . A gear transmission  91  is installed on a motor  90  and drives an eccentric disk  92  with a pin  94  inserted into it. When the eccentric disk  92  rotates, the pin  94  now moves on a circular path. A slide  95  in which the pin  94  is guided is moved to and fro by this circular motion, the slide being itself guided in guide rails  96  and  97 . The movement of the slide  95  effects a tensile force on a respective one of the cables  80   a  or  80   b . The cables are guided over rollers  98   a ,  98   b ,  99   a ,  99   b ,  100   a  and  100   b  (not shown), and then pull the patient&#39;s knee into an extension by means of a hook  101   a  or  101   b  on the knee cuff. 
     Cushions  102   a  and  102   b  of foam material covered with plastic protect the hollows of the patient&#39;s knees from injury during extension, and press the knee toward flexion again when the cable  80   a  or  80   b  is relaxed. The cushions are on a plate  108  which has guide tubes  109   a  and  109   b  on either side, with fastening screws  110   a  and  110   b.    
     A respective tensioning device  103   a  or  103   b  is mounted on the cables  80   a  and  80   b , and enables the cables to be adjusted in length. This permits the tension on the hooks  101   a  or  101   b  to be adjusted so that the patient&#39;s knee is stretched as far as an extension by the movement of the eccentric disk  92 . 
     Hook-and-loop bands similar to those described in FIG. 6 can be used as knee cuffs with which the patient&#39;s knee is fastened to the hooks  101   a  or  101   b.    
     FIG. 8B shows a top view of the eccentric drive of FIG.  7 . The motor  90  can be seen, with the gear transmission  91  on which the eccentric drive  92  is situated. In this, various holes  93  are provided so that the pin  94  can be inserted into the eccentric disk  92  at different radii. The stroke length of the knee movement can be set larger or smaller by the different positioning of the pin  94  in the holes  93 . Rollers  104 - 107  are mounted on the slide  95  and mount the plate in the guide rails  96  and  97 . The two cables  80   a  and  80   b  are also fastened to the slide  95 . 
     In contrast to the first embodiment example, a considerably simpler control mechanism is required here, since the motor can simply rotate and the extension or flexion of the leg results automatically. The control unit controls only the speed of the motor  90  and thus controls the frequency of the movement of the patient&#39;s leg. In the first embodiment example, the control unit has to always switch the drive over on reaching the end positions, from an upward movement to a downward movement and vice versa. 
     FIG. 9 shows the foot mechanism  83  of FIG. 7 in a perspective diagram. Respective rectangular tubes  121   a  and  121   b  are securely connected to the underside of a plate  120 . These serve as guides for the foot mechanism on the rails fastened to the leg portion. The foot mechanism can be screwed fast with fastening screws  122   a  and  122   b  at the correct position in therapy. A support  123  is fastened to the plate  120  and a second support  124  is mounted on its upper end. A respective footplate  125   a  or  125   b  is situated on either side of the support  124 , and is capable of rotation around a bearing at the point of attachment to the support  124 . A respective footplate  125   a  or  125   b  is situated on either side of the support  124  and is capable of rotation around a bearing at the point of attachment to the support  124 . Respective levers  126   a ,  126   b  (not shown) are fastened to the footplates, and are connected together by means of a steel cable  127 . This steel cable  127  runs over a roller  128  and serves as a reciprocating mechanism. When a footplate is pressed downward, the other moves upward. Respective springs  129   a  or  129   b  are situated under the footplates  125   a  and  125   b , and are tensioned on respective plates  130   a  or  130   b . If one of the footplates pressed downward (extension) by the patient&#39;s leg, the other leg is automatically bent by the reciprocating mechanism. In addition, a weight force (afferent input) arises on the sole of the patient&#39;s foot due to the spring  129  when the leg is extended. 
     The patient&#39;s leg can be secured with respective cuffs  131   a  or  131   b , which are connected to the footplates  125   a ,  125   b  by means of respective connecting cables  132   a  or  132   b . It is thus laterally stabilized so as not to tilt to the side in the bent state. A heel holder  133   a  or  133   b  protects the patient&#39;s foot from slipping down from the footplate  125   a  or  125   b.    
     With the active standing table according to the invention, it is possible to control the course of movement of all joint planes (hip, knee, foot) of the patient&#39;s lower extremities in a physiological pattern (kinematic and kinetic) as similar as possible to that of walking. The most important movement quantities for a successful locomotion therapy (excitation of locomotive activity) are the hip joint extension and the weight loading of the sole of the foot during the extension phase of the leg. Both parameters can be individually matched to the patient&#39;s needs with the active standing table described here. 
     In addition the active standing table can be adapted to the individual differences of patients&#39; measurements. 
     Results can be attained with locomotion therapy on the active standing table, because training can be begun very early, i.e., even when the patient should not be raised upright.