JP6975464B2 - Implantable motion assist device - Google Patents

Description

The present invention relates to an implantable motion assist device that is implanted and used in the wearer's body in order to assist movements centered on joints such as hip joints and knee joints.

This type of implantable motion assist device is disclosed in Patent Documents 1 and 2. In the powered artificial joint disclosed in Patent Document 1, an actuator is incorporated in the artificial joint, and an assist force for moving the artificial joint is applied to the artificial joint. Artificial joints are not suitable for people who have healthy joints but have difficulty walking or other movements due to weakened muscles.

In the implantable motion assisting device disclosed in Patent Document 2, each of the two rims driven by the electric motor is fixed to each bone connected to the joint, and the assisting force from the electric motor is applied to each bone. I am doing it. It can be used for people who have healthy joints but have difficulty in walking and other movements.

In the operation assist device disclosed in Patent Documents 1 and 2, the rotational force of the electric motor is transmitted to each bone via a rigid body member. A rigid member for transmitting an assist force rotates in the front-rear direction of the human body around a mechanical joint axis provided in the motion assist device. The assist force generated by the motion assist device acts on the joints of the human body centering on a fixed position.

The movement of each joint of the human body is complicated. For example, in the knee joint, the joint axis of the knee joint twists and moves in the anteroposterior and vertical directions with the flexion and extension movement of the knee. In ball joints such as hip joints and shoulder joints, the center of the joint does not move substantially, but in addition to anterior-posterior flexion and extension movements, adduction / abduction movements, internal rotation / external rotation movements, and These complex movements occur.

In a conventional general motion assist device, an assist force transmission system is configured from a rigid body member, and the central position of the assist force that assists the bending and stretching motion is fixed. With such a motion assist device, it is not possible to follow a complex motion centered on a human body joint, and it is not possible to reproduce the original natural motion. When the motion assist device is attached, the movement of the joint portion assisted by the motion assist device is constrained by the motion of the motion assist device. As a result, an unnecessary force acts on the joint portion of the human body, and the joint may not move, or the wearer may feel restrained or uncomfortable.

On the other hand, Patent Documents 3 and 4 propose an exterior type operation assist device. In the motion assist device described in Patent Documents 3 and 4, the movement of the joint axis in the anteroposterior direction and the up-down direction accompanying the flexion / extension movement of the knee joint is taken into consideration. It is equipped with a mechanism that moves the axis of rotation of the assisting force of the bending and stretching movements in the front-back and up-down directions according to the bending and stretching movements of the human body.

Japanese Unexamined Patent Publication No. 2006-26197 Japanese Unexamined Patent Publication No. 2009-95382 Japanese Unexamined Patent Publication No. 2007-275482 Japanese Unexamined Patent Publication No. 2013-70783

The implantable motion assist device, which is the object of the present invention, assists a motion such as a walking motion without using an artificial joint as described in Patent Document 2. In such an implantable motion assist device, the movement of the joint axis of the human body accompanying the bending and stretching motion has not been considered conventionally. Further, an implantable motion assist device suitable for use in a hip joint or the like in which an adduction / abduction motion, an medial / external rotation motion, and a combined motion thereof occur in addition to a flexion / extension motion has not been proposed.

It is conceivable to apply the exterior-type motion assist device described in Patent Documents 3 and 4 above to the implantable motion assist device used for the knee joint. That is, it is conceivable to adopt a mechanism for moving the rotation axis of the assist force on the device side in the front-back and up-down directions. However, the mechanism for moving the rotation axis of the assist force in the exterior type operation assist device uses a complicated link mechanism or a plurality of actuators to move the rotation axis in the front-rear direction. Such a mechanism has a complicated structure, is not easy to miniaturize, and is not suitable for implantation in the body.

Further, the conventional mechanism reciprocates the rotation axis of the assist force along a trajectory uniquely determined. However, the movement of the joint axis of the joint portion of the human body accompanying the bending and stretching movement in walking motion and the like is complicated. Even if the center of rotation of the assist force on the side of the motion assist device is moved along a uniquely determined trajectory, the joint may not move. In addition, it may not be possible for the wearer to realize an assist operation that does not give a feeling of restraint or discomfort.

Further, in the exterior type operation assist device, for example, it is possible to play with the state in which the device is attached to the human body. This play makes it relatively easy to absorb the deviation between the movement of the joints of the human body and the movement of the device. In the implantable motion assist device, the device components are arranged in a limited space in the body. Each component is fixed to each of the pair of bones connected to the joint without play. When a gap occurs between the movement on the device side and the movement on the human body side, it acts as a large binding force on the wearer's joint.

An object of the present invention is to provide an implantable motion assist device capable of transmitting a required assist force to a joint portion without restraining the natural movement of each joint of the human body.

The implantable motion assist device according to the present invention is used by being implanted in the body to assist the movement of the wearer's joints. In the implantable motion assist device according to the present invention, the pair of bones that perform relative movement around the joint are called the first and second bones, and the first bone or the tendon connected to the first bone is the first. If the second bone or the tendon connected to the second bone is called the second part, the tensile force for assisting the movement in the first direction in the relative movement is the first, It is characterized by having a flexible linear member used for transmitting between the second portions and an actuator that applies a tensile force to the linear member.

In the present invention, the "linear member" means a wide and long member, and includes various forms of elongated members called strings, wires, ropes, tapes, bands and the like. Further, various cross-sectional shapes such as a circular cross-section, a flat elliptical cross-section, and a hollow cross-section are included. Further, it includes a linear member made of one linear material and a linear member in the form of a thread obtained by bundling a plurality of linear materials (fibrous materials). The linear member may be a member having sufficient tensile strength to transmit the required assisting force and having sufficient flexibility or flexibility to follow the movement of the joints of the human body. Just do it. As the material of the linear member, for example, carbon fiber, titanium, a high molecular polymer, or the like can be used.

In the present invention, for example, a linear member is bridged between the first and second portions, and an actuator is engaged with the linear member so that the length of the bridging portion of the linear member can be increased or decreased. Let me.

Alternatively, the wire can be attached so that the actuator can be attached to one side of the first and second portions, one end of the linear member can be attached to the other side, and the other end side of the linear member can be pulled. Engage the actuator with the other end of the shaped member.

In a joint whose main extension / flexion movement is, for example, a knee joint, the actuator is driven in a direction in which the length of the bridging portion of the linear member is shortened. Alternatively, the linear member is directly pulled by the actuator. As a result, an assisting force for the stretching movement in which both bones are relatively stretched around the knee joint can be applied as a tensile force via the linear member. When the length of the bridging part of the linear member is returned to the original length, or when the linear member is loosened, the assist force (tensile force) is released and the bending motion in which both bones approach each other becomes possible. ..

Similarly, even in the case of a ball joint type joint, for example, a hip joint, an assist force for bending and stretching movements centered on the hip joint can be applied in the form of a tensile force. Further, an assist force for adduction motion or abduction motion, and an assist force for internal rotation motion or external rotation motion can be applied from the actuator in the form of a tensile force via a linear member.

The transmission path of the assist force is formed by a flexible linear member, and the rotation axis or the rotation center of the assist force is not defined on the device side. The assist force always acts on the joint around the joint axis or the center of the joint of the human body. It is possible to transmit assist force while following the natural movement of both bones centered on the joints of the human body. For example, in the case of a joint such as a knee joint where flexion movement is the main, the assist force is always centered on the joint axis of the human body joint without restraining the movement of the joint axis of the joint accompanying the flexion / extension movement of both bones. Will be added. Further, in a ball joint system joint, for example, in a hip joint, a linear member arranged so that an assist force is applied in the flexion / extension direction between bones connected to the hip joint is a part on the human body side centered on the joint center. It bends or twists following the movement in each direction. For example, it does not restrain the adduction / abduction movement centered on the hip joint.

According to the present invention, by using a flexible linear member, it is possible to simulate a motor function centered on a joint by an inherent muscle or the like. Therefore, unlike the conventional device composed of rigid body links, the mobility of the joints can be maintained at each joint in the human body, and the wearer's joints are assisted with no binding force or discomfort or with less discomfort. You can apply force.

In the present invention, it is desirable that at least a part of the linear member is covered with the tubular member. It is desirable that the tubular member has at least flexibility among flexibility and elasticity.

Flexibility of a tubular member means flexibility or flexibility that can follow the movement of a linear member. Further, the elasticity of the tubular member means the elasticity that can follow the increase / decrease in the length of the bridging portion of the linear member. Usually, it suffices if a tubular member having a length corresponding to the maximum bridge length is arranged and has elasticity that can be reduced to a length corresponding to the minimum bridge length.

The linear member embedded in the human body moves within a predetermined range as the human body moves around the joint. The linear member may come into direct contact with the surrounding human tissue and cause damage. By covering the linear member with a tubular member (tube, sheath) from a material that does not cause adverse effects such as damage even if it comes into contact with surrounding human tissue, the human body within the range of movement of the linear member It can prevent damage to the tissue. Further, in this way, it becomes possible to use various materials as the linear member without being restricted by the adaptability to the human body tissue.

In the present invention, it is desirable to arrange a damper in the transmission path of the tensile force between the actuator and the linear member. As the "damper", for example, a flexible elastic body such as a coil spring, a torsion spring, a leaf spring, and rubber, and various other elastic members can be used. The elastic member does not substantially elastically deform when the required tensile force is transmitted, and elastically deforms when a tensile force exceeding the required tensile force is applied, and the transmitted tensile force has a predetermined magnitude. Do not exceed that.

When the actuator is stopped, an external force may act from the side of the joint portion via the linear member. For example, in the case of a knee joint, the knee joint may be unintentionally flexed or extended due to the wearer tripping on a step or the like. In such a case, a large impact force acts on parts such as the linear member and the actuator, and these parts may be damaged. By arranging a damper, for example, a coil spring on the transmission path of the tensile force, the impact force can be alleviated and adverse effects such as damage to each part can be avoided.

In the present invention, in order to transmit a tensile force for assisting a movement in a second direction opposite to the first direction in a relative movement centered on a joint portion between the first and second parts. It may have an elastic member for use by bridging between the first part and the second part.

For example, a linear member that gives an assist force in the flexion direction or extension direction centered on a joint, and an elastic member that gives a return force for returning the flexion state to the extension state or a return force for returning the extension state to the flexion state. Can be used in combination with. Similarly, a combination of a linear member that gives an assist force in the adduction direction or the abduction direction centered on the joint and an elastic member that gives a return force to return the adduction state or the abduction state to the original state. Can be used. Further, a combination of a linear member that gives an assist force in the internal rotation direction or the external rotation direction centered on the joint and an elastic member that gives a return force for returning the internal rotation state or the external rotation state to the original state is used. be able to.

Here, as the "elastic member", a flexible elastic body such as a tension coil spring, a compression coil spring, a torsion spring, a leaf spring, and rubber, and various other elastically deformable members such as elastic expansion and contraction are used. Can be done.

In the present invention, various actuators can be used as the actuator. For example, a member that winds up and unwinds a linear member by a rotary motion can be used. Further, a device that pulls in and outs the linear member by a linear motion, a device that pulls the linear member by a stretching motion of the telescopic member, and the like can be used.

Further, the actuator can be arranged on the surface of the first or second bone or inside the first or second bone.

On the other hand, as the actuator, a polymer actuator used as an artificial muscle or the like can be used. In this case, for example, a polymer actuator can be used to form a part of the linear member. As such a polymer actuator, for example, an actuator element provided with a dielectric layer made of PVC proposed in Japanese Patent Application Laid-Open No. 2015-122935 by the applicant of the present application can be used.

Various members (mounting methods) are used to attach the linear members (first and second linear members) to the first and second portions so that the tensile force can be transmitted. Can be used. For example, a nail, a screw or a bolt used to fix a linear member to a first part or a second part, a strip member used to fasten a linear member to a first part or a second part, a wire. An adhesive material used for joining the shaped member to the first portion or the second portion, a suture member used for suturing the linear member to the first portion or the second portion, and the like can be used.

In the present invention, in order to construct the assist force transmission mechanism without imposing an excessive load on the wearer's joints, bones, etc., an intramedullary nail may be inserted and fixed in the medullary cavity of the bone. In this case, a linear member or actuator can be attached to the intramedullary nail.

Next, the linear member can be used to apply an assisting tensile force in either the first direction of the relative movement around the joint and the opposite second direction. For example, a set of linear members or 2 so that expansion and contraction are performed in opposite phase in order to apply a tensile force for assisting both flexion and extension movements to the joint portion via the linear member. A set of linear members may be arranged. In addition, one set so that expansion and contraction are performed in opposite phases in order to give an assist force by a linear member to both relative movements centered on joints such as hip joints, for example, adduction movements and abduction movements. The linear member or two sets of linear members may be arranged.

Therefore, in the present invention, when the linear member is used as the first linear member, it assists the movement in the second direction opposite to the first direction in the relative movement centering on the joint portion. One or more flexible second lines for use across the first and second sites so that the tensile force is transmitted to the first and second sites. It has a member. The actuator is connected to the first and second linear members so that the length of the bridging portion between the first and second portions of the first and second linear members increases or decreases in opposite phase. NS.

Instead, the linear member is used as a bridging portion between the first and second portions, with a first bridging portion for transmitting a tensile force that assists the movement in the first direction in relative motion. A bridge between the first and second parts so that a second bridge portion for transmitting a tensile force that assists the movement in the second direction opposite to the first direction is formed. You may. In this case, the actuator is engaged with the linear member so that the lengths of the first and second bridging portions increase or decrease in opposite phases.

Further, in the present invention, in order to assist the movement in the first direction in the relative movement around the joint portion, the first linear member and the first actuator are arranged to assist the movement in the second direction. A second linear member and a second actuator can be arranged for this purpose.

The implantable motion assist device of the present invention can be used, for example, as a device that assists the wearer's flexion / extension movement centered on the hip joint, adduction / abduction movement or medial / external rotation movement, and flexion / extension movement centered on the knee joint. can. Further, the implantable motion assist device of the present invention can be widely used for a person who can move by himself / herself but has difficulty in healthy movement and has a different degree of difficulty in movement. Furthermore, it can also be used for people who cannot perform movements such as walking due to lack of muscle strength.

It is a schematic block diagram at the time of looking at the body-embedded walking assist device of Embodiment 1 to which this invention was applied from the front side of a human body. FIG. 3 is a schematic configuration diagram when the implantable assist device of FIG. 1 is viewed from the left outside of the human body. FIG. 2 is a schematic configuration diagram showing a state in which the left hip joint and the left knee joint in the upright state of FIG. 2 are flexed. It is explanatory drawing which shows the knee joint assist mechanism of the body implant type of Embodiment 2 to which this invention was applied, and the explanatory drawing of the linear motion actuator.

[Embodiment 1]
Embodiment 1 shown in FIGS. 1 to 3 applies the present invention to an implantable walking assist device including a hip joint motion assist unit and a knee joint motion assist unit.

(overall structure)
FIG. 1 is a schematic configuration diagram of the implantable walking assist device according to the first embodiment when viewed from the front side of the wearer. FIG. 2 is a schematic configuration diagram of an upright state when the implantable walking assist device is viewed from the left outside, and FIG. 3 is a schematic configuration diagram showing a state in which the left hip joint and the left knee joint are flexed from the upright state. The implantable walking assist device 1 (hereinafter, simply referred to as “assist device 1”) is embedded in the wearer's body, in this example, in the left leg 11, and the hip joint 12 and the hip joint 12 accompanying the walking motion of the left leg 11 It assists the bending and stretching movement of the knee joint 13.

The assist device 1 is embedded in the left hip joint 12 and is embedded in the hip joint motion assist unit 2 that assists the anterior-posterior flexion / extension movement during walking around the hip joint 12 and the left knee joint 13. It is provided with a knee joint motion assist unit 4 that assists in bending and stretching movements before and after walking around the knee joint 13.

The assist device 1 includes, for example, a human body-mounted battery power supply (not shown) and a control unit (not shown), and the drive power from the battery power supply to the hip joint operation assist unit 2, the knee joint operation assist unit 4, and the control unit. Is supplied. The control unit controls the drive of the hip joint movement assist unit 2 and the knee joint movement assist unit 4 in conjunction with the movement of the human body by, for example, a control method using a neural oscillator model. The applicant of the present application proposes such a control method in Japanese Patent Application Laid-Open No. 2015-44240.

(Hip joint movement assist unit)
The hip joint movement assist unit 2 is provided on an intramedullary nail 21 inserted into the intramedullary cavity of the femur 14, a screw screw 22 for fixing the intramedullary nail 21 to the femur 14, and, for example, the ilium 15 on the pelvic side. It has a screw screw 23 to be fixed, and a rotary actuator 24 for generating an assist force to which a housing 24a is fixed to the screw screw 23.

Further, as shown in FIGS. 2 and 3, the hip joint operation assist unit 2 includes the front winding shaft 25 and the rear winding shaft 26, which are rotatably supported by the housing 24a of the rotary actuator 24, and the femur. It has a screw screw 27 fixed to the epiphysis on the upper side of the bone 14, and a first string 28 and a second string 29, which are flexible linear members. These first and second strings 28 and 29 are, for example, narrow tape-shaped or band-shaped strings.

The first string 28 is unwound from the front winding shaft 25 located on the front side of the human body and spanned over the screw front end 27a located on the same side of the screw screw 27. Similarly, the second string 29 is unwound from the rear winding shaft 26 located on the rear side of the human body and spanned over the screw rear end 27b located on the same side of the screw screw 27. Therefore, the first string 28 and the second string 29 are bridged between the ilium 15 and the femur 14 on the pelvic side at positions in front of and behind the human body with the hip joint 12 sandwiched between them.

In this example, the anterior take-up shaft 25 supported by the housing 24a fixed to the screw screw 23 fixed to the pelvis side functions as a part for bridging the first string 28 to the bone on the pelvis side. The screw front end 27a of the screw screw 27 on the side of the femur 14 functions as a site for connecting (fixing) the first string 28 to the femur 14. Similarly, the posterior take-up shaft 26 functions as a site for bridging the second string 29 over the bone on the pelvic side, and the screw rear end 27b of the screw screw 27 on the femur 14 side is the second string. It functions as a site for bridging (fixing) 29 to the femur 14.

Here, the bridging portion 28a between the front take-up shaft 25 and the screw front end 27a of the screw screw 27 in the front first string 28 is covered with a flexible tube 31. The tube 31 has, for example, a bellows structure and can be expanded and contracted in the length direction thereof. Similarly, the bridging portion 29a between the rear take-up shaft 26 and the screw rear end 27b of the screw screw 27 in the rear second string 29 is covered by the flexible tube 32. The tube 32 also has a bellows structure, for example, and can be expanded and contracted in the length direction thereof.

For example, a pinion 33 is coaxially fixed to the rotating shaft 24b of the rotary actuator 24. The front transmission gear 34 and the rear transmission gear 35 are engaged with the pinion 33 from the front-rear direction of the human body. The front transmission gear 34 is coaxially fixed to the front take-up shaft 25, and the rear transmission gear 35 is coaxially fixed to the rear take-up shaft 26.

The first string 28 is wound, for example, clockwise around the front take-up shaft 25, and the second string 29 is wound counterclockwise around the rear take-up shaft 26. For example, in the state of FIG. 2, when the rotary actuator 24 is driven and the rotary shaft 24b rotates in one direction, the first string 28 is wound around the front take-up shaft 25 and the front side is taken up as shown in FIG. The length of the bridging portion 28a of the first string 28 spanning from the take-up shaft 25 to the screw front end 27a of the screw screw 27 of the femur 14 is shortened. In other words, the distance from the front take-up shaft 25 to the screw front end 27a is shortened.

As a result, the rotational force of the rotary actuator 24 is applied to the femur 14 via the first string 28 as an assist force in the direction in which the femur 14 bends forward with respect to the pelvis around the center of the hip joint 12. It works. Since the tube 31 has elasticity and contracts as the length of the bridging portion 28a decreases, it does not interfere with the winding operation of the first string 28.

Further, as shown in FIG. 3, the second string 29 on the rear side is unwound by the rotation of the rear winding shaft 26 in the same direction, the length of the bridging portion 29a becomes long, and the femur is formed. It does not interfere with the bending motion of 14. As the bridging portion 29a becomes longer, the tube 32 expands accordingly, so that the second string 29 is not exposed and comes into contact with the surrounding human tissue.

When the rotary actuator 24 is rotated in the opposite direction, the length of the bridging portion 28a of the first string 28 on the front side becomes long, and the length of the bridging portion 29a of the second string 29 on the rear side becomes short. As a result, the rotational force of the rotary actuator 24 acts on the femur 14 via the second string 29 as an assist force in the direction in which the femur 14 extends posteriorly with respect to the pelvis around the hip joint 12. Also in this case, the tubes 31 and 32 expand and contract according to the change in the length of the bridging portions 28a and 29a, and return from the state of FIG. 3 to the state of FIG. 2, for example.

Here, when an adduction or abduction motion, an internal rotation or an external rotation motion, or a combined motion thereof occurs in a portion on the side of the femur 14 centering on the hip joint 12, it is flexible. Some first and second strings 28, 29 bend or twist following such movements. Therefore, it is possible to prevent the hip joint motion assist unit 2 from becoming an obstacle to the adduction / abduction motion. Further, if the rotary actuator 24 is driven and controlled so as to unwind and rewind the first and second strings 28 and 29 in accordance with such an adduction / abduction motion, the wearer does not feel restrained or uncomfortable. Can perform adduction and abduction movements.

Further, a flexible linear member such as a string is laid so that a tensile force that assists one or both of the adduction / abduction motion and the inward / outward rotation motion can be applied, and the extension length is rotated. It can also be increased or decreased by an actuator such as an actuator. By doing so, it is possible to assist the adduction / abduction movement and the internal / external rotation movement.

The rotary actuator 24 includes, for example, an electric motor and a speed reducer that decelerates the output rotation and transmits the output rotation to the rotary shaft 24b. Further, the embedding position of the rotary actuator 24 is set to a position slightly upward from the left lateral position of the hip joint 12, for example, so that the embedding space can be easily secured.

(Knee joint movement assist unit)
Next, the knee joint movement assist unit 4 has a screw screw 42 for fixing the above-mentioned intramedullary nail 21 inserted into the intramedullary cavity of the femur 14 and the lower end portion 21b of the intramedullary nail 21 to the femur 14. The housing 44a is fixed to the intramedullary nail 41 inserted into the tibia 17, the screw screw 43 for fixing the upper end side portion 41a of the intramedullary nail 41 to the tibia 17, and the screw screw 42 on the side of the femur 14. It has a rotary actuator 44 for generating an assist force.

Further, the knee joint motion assist unit 4 is fixed to the anterior take-up shaft 45 and the posterior take-up shaft 46, which are rotatably supported by the housing 44a of the rotary actuator 44, and the epiphysis on the upper side of the tibia 17. It has a screw screw 47 and a flexible first string 48 and a flexible second string 49.

The first string 48 is unwound from the front winding shaft 45 located on the front side of the human body and spanned over the screw front end 47a located on the same side of the screw screw 47. Similarly, the second string 49 is unwound from the rear winding shaft 46 located on the rear side of the human body and spanned over the screw rear end 47b located on the same side of the screw screw 47. The first string 48 and the second string 49 are bridged between the femur 14 and the tibia 17 at the positions before and after the human body with the knee joint 13 sandwiched between them.

The anterior take-up shaft 45 functions as a member for connecting the first string 48 to the side of the femur 14, and the screw front end 47a of the screw screw 47 on the side of the tibia 17 hangs the first string 48 to the tibia 17. It functions as a member for passing. Similarly, the posterior take-up shaft 46 functions as a member for bridging the second string 49 to the femur 14, and the screw rear end 47b of the screw screw 47 on the tibia 17 side holds the second string 49. It functions as a member for bridging over the tibia 17.

The bridging portion 48a between the front take-up shaft 45 of the front first string 48 and the screw front end 47a of the screw screw 47 is covered with a flexible tube 51. The tube 51 has, for example, a bellows structure and can be expanded and contracted in the length direction thereof. Similarly, the bridging portion 49a between the rear take-up shaft 46 of the rear second string 49 to the screw rear end 47b of the screw screw 47 is covered by the flexible tube 52. The tube 52 also has a bellows structure, for example, and can be expanded and contracted in the length direction thereof.

A pinion 53 is coaxially fixed to the rotation shaft 44b of the rotation actuator 44. The front transmission gear 54 and the rear transmission gear 55 are engaged with the pinion 53 from the front-rear direction of the human body. The front transmission gear 54 is coaxially fixed to the front take-up shaft 45, and the rear transmission gear 55 is coaxially fixed to the rear take-up shaft 46.

The first string 48 is wound, for example, clockwise around the front take-up shaft 45, and the second string 49 is wound counterclockwise around the rear take-up shaft 46. For example, in the state of FIG. 2, when the rotary actuator 44 is driven and the rotary shaft 44b rotates in one direction, the second string 49 is unwound from the rear take-up shaft 46 as shown in FIG. The length of the bridge portion 49a of the second string 49 spanned from the posterior anterior take-up shaft 46 to the screw rear end 47b of the screw screw 47 of the tibial bone 17 becomes longer.

As a result, the rotational force of the rotary actuator 44 acts on the tibia 17 via the second string 49 as an assist force in the direction in which the tibia 17 flexes posteriorly with respect to the femur 14 around the knee joint 13. .. The tube 52 is elastic and stretches as the length of the bridging portion 49a increases, and does not interfere with the winding operation of the second string 49.

Further, the first string 48 on the anterior side is unwound by the rotation of the anterior winding shaft 45 in the same direction, the length of the bridging portion 48a is shortened, and the first string 48 on the anterior side does not interfere with the extension movement of the tibia 17. As the bridging portion 48a becomes longer, the tube 51 shrinks accordingly, so that the first string 48 is not exposed and comes into contact with the surrounding human tissue to cause damage.

When the rotary actuator 44 is rotated in the opposite direction in the state of FIG. 3, as shown in FIG. 2, the length of the bridging portion 48a of the first string 48 on the front side becomes shorter, and the length of the second string 49 on the rear side becomes shorter. The length of the bridging portion 49a becomes long. As a result, the rotational force of the rotary actuator 44 acts on the tibia 17 via the first string 48 with the assist force in the direction in which the tibia 17 extends forward with respect to the femur 14 around the knee joint 13. Also in this case, the tubes 51 and 52 expand and contract according to the change in the length of the bridging portions 48a and 49a.

The rotary actuator 44 includes, for example, an electric motor and a speed reducer that decelerates the output rotation and transmits the output rotation to the rotary shaft 44b. Further, the embedding position of the rotary actuator 44 is set to a position slightly upward from the left lateral position of the knee joint 13, for example, so that the embedding space can be easily secured.

(Modified example of Embodiment 1)
In the above example, in the hip joint 12 and the knee joint 13, the first and second strings 28, 29, 48, and 49 are arranged one by one before and after the hip joint 12. It is also possible to use a plurality of strings as the first and second strings, respectively. Further, by routing one or a plurality of strings that function as the first and second strings, the front bridging portions 28a and 48a become long, and the rear bridging portions 29a and 49a become short. It is also possible to.

Further, for example, in the knee joint 13, a state in which a compressive force acts between the femur 14 and the tibia 17 with an elastic member such as a coil spring or a torsion spring instead of the second string 49 on the posterior side which is the flexion side. It is also possible to bridge it to. For example, by pulling the string in a direction in which its length becomes shorter, the extension motion of the knee joint can be assisted, and the flexion motion of the knee joint can be assisted by the compressive force of the elastic member. Further, it is possible to use the string and the elastic member on the side of the hip joint 12.

Further, in the knee joint 13, a first string 48 for extension on the anterior side is bridged between the femur 14 and the tibia 17. Instead, a first string 48 can be bridged between the first femur 14 and the patella 18 so that the tibia 17 extends through the patella 18.

Furthermore, in the above example, an assist force is generated by using a rotary actuator. Instead of this, it is also possible to use a polymer actuator used for artificial muscles and the like. In this case, for example, a part of the first and second strings 28, 29, 48 and 49 is formed by a polymer actuator and expanded and contracted in the direction of the string length to form the bridging portions 28a, 29a and 48a. The length of 49a can be increased or decreased.

In the above example, the wearer's bone is reinforced by using an intramedullary nail. When the wearer's bone is strong, the actuator, the first and second strings, and the like can be fixed to each bone without using an intramedullary nail.

[Embodiment 2]
FIG. 4A is an explanatory diagram showing a knee joint assist mechanism according to the second embodiment to which the present invention is applied, and FIG. 4B is an explanatory diagram showing a linear motion actuator. The knee joint assist mechanism 100 includes an extension assist unit 110 that is embedded in the left leg of the wearer and assists the extension movement in the anterior-posterior direction of the human body centering on the left knee joint 13, and a flexion assist unit 130 that assists the flexion movement. , A human-mounted control unit 150 with a built-in battery power supply and control mechanism.

The control unit 150 controls the drive of the extension assist unit 110 and the flexion assist unit 130 in conjunction with the movement of the human body by, for example, a control method using a neural oscillator model (see JP-A-2015-44240). For example, the control unit 150 alternately drives and controls the extension assist unit 110 and the flexion assist unit 130 in the walking motion to assist the knee joint movement.

The extension assist unit 110 is a flexible wire 111 used to transmit the tensile force for assisting the extension movement to one of the femur 14 and the tibia 17, which is connected to the knee joint 13, in this example, the tibia 17. And a linear motion actuator 120 attached to the femur 14 in order to apply a tensile force to the wire 111.

The lower end 111a of the wire 111 is fixed to the anterior portion of the upper end of the tibia 17. The wire 111 extends upward through the patella 18, and the upper end 111b of the wire 111 is connected to the side of the linear actuator 120. The amount of traction of the wire 111 by the linear actuator 120 is required to be about 60 mm in order to extend the knee joint 13 from 90 ° to 0 °. A linear actuator with a stroke exceeding this may be used.

The fixing portion 112 for fixing the lower end 111a of the wire 111 to the tibia 17 can be a fixing portion by a nail, a screw, a bolt, a fastening band or the like, or a fixing portion by adhesion or suturing. The portion of the wire 111 that contacts the human tissue is covered by a flexible and stretchable cylinder 113. This makes it possible to prevent the moving wire 111 from damaging the human tissue.

The linear actuator 120 is, for example, arranged along the lateral side surface of the femur 14 and fixed to the femur 14. For example, the linear actuator 120 can be manufactured as the intramedullary nail 21 in the first embodiment and embedded in the femur 14.

Explaining with reference to FIG. 4B, the linear motion actuator 120 is a ball screw type actuator, which is a slender cylindrical case 121, a ball screw shaft 122 extending coaxially inside the case, and a ball screw shaft 122. It includes a matching ball screw 123 and a servo motor 124 that rotationally drives the ball screw 122. In some cases, a motor and a reducer are combined to secure the required torque. The ball screw shaft 122 is supported by the cylindrical case 121 in a rotatable state, and the ball screw 123 is supported by the cylindrical case 121 in a slidable and non-rotatable state along the ball screw shaft 122. .. When the servomotor 124 is driven to rotate the ball screw shaft 122, the ball screw 123 slides along the ball screw shaft 122 in the front-rear direction indicated by the arrow 126.

The upper end 111b of the wire 111 is connected to the ball screw 123 via a coil spring 125 that functions as a damper. When the ball screw 123 slides backward, the wire 111 is pulled and pulled in (the wire spanning length from the tip position 120a of the linear actuator 120 to the lower end 111a of the wire 111 connected to the tibia 17 side). Is shortened.). The tensile force in the direction of extending the tibia 17 to the femur 14 in the anterior direction of the human body with the knee joint 13 as the center via the wire 111 acts as an assist force. When the ball screw 123 is slid forward, the wire 111 is loosened and the tibia 17 is released from tension. The wearer can freely flex the tibia 17 posteriorly with respect to the femur 14 around the knee joint 13.

Returning to FIG. 4A again, the bending assist unit 130 has the same structure as the extension assist unit 110, but the mounting position is different. The flexion assist unit 130 has a flexible wire 131 used to transmit a tensile force for assisting the flexion movement to one of the bones connected to the knee joint 13, in this example, the tibia 17, and a tensile force to the wire 131. It is equipped with a linear acting actuator 140.

The lower end 131a of the wire 131 is fixed to the posterior portion of the upper end of the tibia 17 or fibula 19. For example, the lower end 131a of the wire 131 is fixed to the biceps femoris attachment or the posterior cruciate ligament attachment in the tibia 17. The upper end 131b of the wire 131 is connected to the side of the linear actuator 140. The linear actuator 140 is, for example, arranged along the medial side surface of the femur 14 and fixed to the femur 14.

When the linear actuator 140 is driven and the ball screw is slid backward, the wire 131 is pulled. A tensile force in the direction of bending the tibia 17 posteriorly with respect to the femur 14 around the knee joint 13 via the wire 131 acts as an assist force. When the ball screw is slid forward, the wire 131 is loosened and the tensile force is released.

[Other embodiments]
INDUSTRIAL APPLICABILITY The present invention is an implantable motion assist device attached to the shoulder joint to assist movements other than walking, for example, raising and lowering the arm, and is attached to the elbow joint to assist movements such as bending and stretching of the elbow. It can be used as an implantable motion assist device. In addition, it can be used as a device for assisting movement by being attached to a joint portion of a human body other than these.

Claims (17)

An implantable motion assist device that is implanted and used in the body to assist the wearer's joint movements.
When the pair of bones that perform relative movement around the joint are the first and second bones, the first bone or the tendon connected to the first bone is called the first site, and the first part is called the first part. Assuming that the second bone or the tendon connected to the second bone is called the second part,
A flexible linear member used to transmit a tensile force for assisting a movement in the first direction in the relative movement between the first and second portions.
It has an actuator that applies the tensile force to the linear member, and has an actuator .
The actuator is engaged with the linear member so that the length of the linear member bridged between the first and second portions can be increased or decreased directly or via the actuator.
An implantable motion assist device in which the tensile force is transmitted between the first and second portions when the actuator is driven in a direction in which the bridging length is shortened. In claim 1,
It has a cylindrical member that covers at least a part of the linear member, and has a cylindrical member.
The tubular member is an implantable motion assist device having at least flexibility among flexibility and elasticity. In claim 1,
An implantable motion assist device having a damper arranged in the transmission path of the tensile force between the actuator and the linear member. In claim 1,
In order to transmit the tensile force for assisting the movement in the second direction opposite to the first direction in the relative movement between the first and second parts, the first part and the said part. An implantable motion assist device having an elastic member for use by straddling between the second parts. In claim 1,
The actuator is an implantable motion assist device that is a rotational drive mechanism, a linear motion mechanism, or an expansion / contraction mechanism that applies the tensile force to the linear member by rotational motion, linear motion, or expansion / contraction motion. In claim 5,
The mounting position of the actuator is an implantable motion assist device in the surface or inside of the first bone or the second bone. In claim 1,
The actuator is an implantable motion assist device, which is a stretchable polymer actuator forming a part of the linear member. In claim 1,
In order to attach the linear member to the first and second portions so that the tensile force can be transmitted.
A nail, screw or bolt used to fix the linear member to the first part or the second part.
A strip-shaped member used to fasten the linear member to the first portion or the second portion.
An adhesive used to join the linear member to the first portion or the second portion, and
An implantable motion assist device having at least one of a suture member used for suturing the linear member to the first portion or the second portion. In claim 1,
It has an intramedullary nail used for inserting and fixing in the medullary cavity of at least one of the first and second bones.
The intramedullary nail is an implantable motion assist device that is a mounting portion of at least one of the linear member and the actuator. In claim 1,
The linear member includes a portion used as a bridging portion to be bridged between the first and second portions.
The actuator is an implantable motion assist device that engages with the linear member so that the length of the bridging portion can be increased or decreased. In claim 10,
Assuming that the linear member is the first linear member and the tensile force is called the first tensile force, it is assumed.
The first and second parts so that the second tensile force assisting the movement in the second direction opposite to the first direction in the relative movement is transmitted to the first and second parts. It has a flexible second linear member for use across the parts.
The actuator has the first and second linear shapes so that the length of the bridging portion between the first and second portions of the first and second linear members increases or decreases in opposite phase. An implantable motion assist device that engages with a member. In claim 10,
It is assumed that the bridging portion of the linear member is referred to as a first bridging portion and the tensile force is referred to as a first tensile force.
The linear member includes the first bridging portion and a second bridging portion for transmitting a second tensile force that assists the movement in the second direction opposite to the first direction. Is a linear member used by being bridged between the first and second parts so that the above-mentioned first and second parts are formed.
The actuator is an implantable motion assist device that engages with the linear member so that the lengths of the first and second bridging portions increase or decrease in opposite phases. In claim 1,
A cylindrical member that covers at least a part of the linear member,
It has a damper arranged in the transmission path of the tensile force between the actuator and the linear member, and an intramedullary nail used for inserting and fixing into the respective medullary cavities of the first and second bones. Ori,
The tubular member has at least flexibility among flexibility and elasticity.
The joint is a knee joint and
The actuator is a rotary actuator for use by attaching to the intramedullary nail that is inserted and fixed to the femur, which is the first bone.
One end of the linear member is an implantable motion assist device that is an end for connecting to the intramedullary nail that is inserted and fixed to the tibia, which is the second bone. In claim 1,
The actuator is an actuator for being attached to one of the first and second portions for use.
One end of the linear member is an end for connecting to the other of the first and second portions.
The actuator is an implantable motion assist device that engages with the linear member so that the other end of the linear member can be pulled. In claim 13,
It has an intramedullary nail used for inserting and fixing in the medullary cavity of at least one of the first and second bones.
An implantable motion assist device in which the actuator is incorporated in the intramedullary nail. In claim 13,
Flexible used to transmit a second tensile force between the first and second portions to assist movement in the second direction opposite to the first direction in the relative movement. The second linear member and
It has a second actuator that applies the second tensile force to the second linear member.
The second actuator is an actuator attached to one of the first and second portions and used.
One end of the second linear member is an end for connecting to the other of the first and second portions.
The second actuator is an implantable motion assist device engaged with the second linear member so that the other end of the second linear member can be pulled. In claim 1,
A cylindrical member that covers at least a part of the linear member,
It has a damper arranged in the transmission path of the tensile force between the actuator and the linear member.
The tubular member has at least flexibility among flexibility and elasticity.
The joint is a knee joint and
The actuator is a linear actuator for attachment to the surface or the inside of the femur, which is the first bone, and is used.
One end of the linear member is an end for connecting to the tibia, which is the second bone.
The linear motion portion of the linear motion actuator is an internal implantable motion assist device connected to the other end of the linear member via the damper.

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