KR20190069084A - A multi-modular helical magnetic millirobot - Google Patents

Abstract

The present invention relates to a multi-modular helical magnetic millirobot, capable of travelling a curved blood vessel, and more particularly, a multi-modular helical magnetic millirobot, capable of inserting a robot into a body with a minimum tissue dissection of 3 to 4 mm in the same manner as a case of a single module in spite of a shape that a plurality of modules are combined. According to the multi-modular helical magnetic millirobot, (a) a blood clot in a blood vessel can be physically removed, (b) stricture and obstruction of the blood vessel are prevented since the blood clot is removed, (c) a drug stent capable of preventing recurrence of the blood clot after removal thereof and providing a drug for angioplasty is mounted, (d) the drug stent is driven as necessary and can be driven even without withdrawal to the outside of the body after being inserted into the body, and (e) a robot can be driven by an external magnetic field so as to be wirelessly driven.

Description

[0001] A MULTI-MODULAR HELICAL MAGNETIC MILLIROBOT [0002]

The present invention relates to a multi-module helical magnetometer capable of traveling a bent blood vessel, and even if a plurality of modules are combined, a robot having a minimum tissue incision of 3 to 4 mm or less To a multi-module helical magnetic milling robot capable of inserting a robot into a body.

In addition, the present invention can be reinforced to (a) physically remove blood clots in blood vessels, (b) prevent blood vessels from stenosis due to the removal of blood clots, (c) (D) a drug stent is provided, which is adapted to be driven as needed, and which can be inserted into the body without being withdrawn from the body again (E) a robot can be driven according to an external magnetic field, so that the robot can be driven wirelessly.

Generally, chronic complete stenosis occurs when lipid-rich cholesterol is deposited on the inner wall of the blood vessel and the lumen is occluded.

The multilayered lipid and thrombus complexes constituting the stenotic lesion thus formed are replaced with collagen as time passes. These collagens form a mass of multimolecular molecules from a single molecule, and the cross-linking reaction and the calcination and then calcified to form a mechanically stable phosphorylated layer to prevent blood circulation.

As a method of treating such chronic stricture, a method of reperfusion and a method of physically perforating a fibrin-collagen complex by chemical decomposition are used.

It is generally known that rotary cutting methods are particularly useful for hardened stricture lesions with calcification. However, currently used physical perforation methods are difficult to penetrate the central part of the lesion along the center of the blood vessel in the process of penetrating the hard calcified lesion, and it is difficult for the angiostatic agent to be injected in the direction of blood flow through the occlusion area of the blood vessel Therefore, there is a problem that it is difficult to secure the shape of the blood vessel after the passage of the entire stricture of the stomach, thereby causing damage and puncture of the inner wall of the blood vessel during the physical procedure.

Therefore, the success rate of vascular intervention is 95% in patients without chronic complete stenosis, but only 70% in patients with chronic complete stenosis.

In addition, a typical mechanism of conventional chronic stricture treatment is to treat with a high stiffness and using a large, sharp wire at the front.

However, such a device has a disadvantage in that it is difficult to precisely align the center of the stent when the wire is pushed and difficult to adjust the direction.

Thus, minimally invasive procedures using microrobots have been actively studied in the treatment of vascular diseases such as chronic obstructive pulmonary disease. In the case of using a microrobot, the incision can be minimized to reduce the suffering of the patient, And does not require a high degree of proficiency by a practitioner as compared with a conventional surgical method.

However, the technology related to the micromanibs disclosed in the related art has a difficulty in securing reliability for driving.

For example, Japanese Patent Application Laid-Open No. 10-2014-0026957 discloses a micro robot and system for treating blood vessels. This technique is applied to blood vessel treatment microsurgical devices capable of removing stenosis of blood vessels wirelessly using an alternating current magnetic field. A microrobot of the present invention includes a housing 110 having a cutting tool 111 at one end and a guide hollow portion 112 formed therein; Since the hammer driving of the microrobot can be performed by the alternating gradient magnetic field generated by the external gradient magnetic field coil part including the permanent magnet 120 which is located in the guide hollow part 110 and can be moved back and forth, So that effective blood vessel treatment can be performed.

However, the above-described technique can (a) physically remove the thrombus in the blood vessel, and (b) reinforce the vessel so as to prevent the vessel from being obstructed due to the removal of the thrombus, (c) a drug stent is mounted that can prevent the recurrence of thrombosis after thrombus removal and can provide a drug to form a blood vessel, (d) allow the drug stent to be driven as needed, (E) the robot can be driven according to an external magnetic field, so that it is not possible to achieve all the purposes of enabling wireless driving.

Published Japanese Patent Application No. 10-2014-0026957 (Mar.

An object of the present invention is to provide a multi-module helical magnetometer capable of traveling a curved blood vessel, and even if a plurality of modules are combined, The present invention provides a multi-module helical magnetic milling robot capable of inserting a robot into a body by incision.

It is a further object of the present invention to provide a method for the prevention of clogging of blood vessels by (a) physically removing blood clots in blood vessels, (b) (D) a drug stent is provided, which is adapted to be driven as needed, after which it is inserted into the body and then returned to the outside of the body (E) a robot can be driven according to an external magnetic field, so that the robot can be driven in a wireless manner, and a multi-module helical magnetic milling robot is provided.

In order to achieve the above object, a multi-module helical magnetometer according to the present invention is a multi-module helical magnetometer (MHMM), wherein each module is connected by a universal joint, Wherein the rotary tip is driven by an external rotating magnetic field (ERMF), and the head module and the tail module including the spiral-shaped body are operated by driving the rotary tip to move within the blood vessel.

In addition, the MHMM includes a head module, a body module, and a tail module, and the ends of the modules include first to fourth connection portions C-1 to C-4 for connecting the universal joints, respectively , And the first connecting part (C-1) to the fourth connecting part (C-4) are rotated by 90 ° relative to each other and perpendicular to each other.

The body module may include a compressed stent on one side of the stent, and a stent cover for compressing the stent outside the stent is formed in a spiral shape. The stent is inflated when the stent cover is removed .

The stent driving unit is connected to the stent cover through a shaft thereof so that when the stent driving unit is driven, the stent cover moves from the body module to the tail module To be moved.

In addition, when the stent is expanded as the stent cover is removed from the body module, the expanded stent supports the inner wall of the blood vessel from which the thrombus is removed by the rotary tip.

Further, the rotary tip uses an NdFeB magnet, wherein the magnet has a magnetization of 955,000 A / m, a thickness of 2 mm, and an inner diameter and an outer diameter of 2.5 mm and 5 mm.

A multi-module helical magnetic milling robot according to the present invention is a multi-module helical magnetic milling robot capable of traveling a curved blood vessel, and even if a plurality of modules are combined, There is an advantage that the robot can be inserted into the body with a minimum tissue incision within ~ 4 mm.

Further, by such a multi-module helical magnetic milling robot,

(a) physically remove blood clots in the blood vessel,

(b) can be reinforced so as to prevent stenosis of the blood vessel due to the removal of the thrombus,

(c) a drug stent is mounted that can prevent the recurrence of thrombosis after thrombus removal and provide a drug to form a blood vessel,

(d) the drug stent is driven to be driven as needed, and is capable of driving the drug stent without being withdrawn from the body after being inserted into the body,

(e) Since the robot can be driven according to an external magnetic field, there is an advantage that it can be wirelessly driven.

1 shows a multi-module helical magnetometer according to the present invention.
FIG. 2 is a diagram showing a motion of a multi-module helical magnetic milling robot according to the present invention in a blood vessel and a schematic structure (b) of an MHMM. FIG.
FIG. 3 shows a multi-module helical magnetic milling robot according to the present invention, in which (a) shows a rotary head mounted on a head module attached to an end, (b) shows a head module (C) shows the geometric configuration of the universal joint connecting the two adjacent modules of the MHMM.
FIG. 4 shows that, when all the Ø _{k and k + 1} are 0, the angular velocity and the acceleration of each module are constant but vary during rotation as the order of Ø _{k, k + 1} and module (k) increases.
FIG. 5 shows an experimental setup for verifying an MHMM according to the present invention, wherein (a) is an MNS for generating and controlling an ERMF, (b) is an MHMM, and (c) (D) shows the MHMM in the in-line state, (e) shows the MHMM in the arc state, and (f) shows the MHMM in the zigzag form.
6 illustrates the helical navigation and unclogging operations of the MHMM in a horizontal bifurcated glass tube with a beating flow that implements a vein flow mimicking a human cardiovascular system.

The terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary meanings and the inventor can properly define the concept of the term to describe its invention in the best possible way And should be construed in accordance with the principles and meanings and concepts consistent with the technical idea of the present invention.

Therefore, the embodiments described in the present specification and drawings are only the most preferred embodiments of the present invention and are not intended to represent all of the technical ideas of the present invention. Therefore, various equivalents And variations are possible.

Before describing the present invention with reference to the accompanying drawings, it should be noted that the present invention is not described or specifically described with respect to a known configuration that can be easily added by a person skilled in the art, Let the sound be revealed.

The present invention relates to a multi-module helical magnetometer capable of traveling a bent blood vessel, and even if a plurality of modules are combined, a robot having a minimum tissue incision of 3 to 4 mm or less To a multi-module helical magnetic milling robot capable of inserting a robot into a body.

In addition, the present invention can be reinforced to (a) physically remove blood clots in blood vessels, (b) prevent blood vessels from stenosis due to the removal of blood clots, (c) (D) a drug stent is provided, which is adapted to be driven as needed, and which can be inserted into the body without being withdrawn from the body again (E) a robot can be driven according to an external magnetic field, so that the robot can be driven wirelessly.

Obstructive vascular disease caused by arterial stenosis or clogging in the human cardiovascular system for a long time has continued to be the main cause of death.

These therapies use low-invasive therapies, called percutaneous coronary interventions, but only limited application because of the structural limitations of the tethered devices used.

On the other hand, since the multi-module helical magnetic millirobot (MHMM) according to the present invention does not require a power transmission device or an actuator, the multi-module helical magnetic milling robot can be efficiently miniaturized, , It is advantageous to drive the blood vessel in a narrow and twisted body.

The multi-module helical magnetometer according to the present invention comprises a head module, a body module and a tail module as shown in FIG. 1 of the accompanying drawings.

1 shows a multi-module helical magnetometer according to the present invention.

The head module is located at the leading end of the traveling direction of the MHMM and has a rotary tip for allowing the MHMM to proceed at an end of the traveling direction of the MHMM. And a first connecting portion C-1 is formed on the rear side of the head body.

The rotary tip has an axis having a direction perpendicular to the traveling direction of the MHMM and the shaft is enclosed in a guide portion formed on the advancing direction side of the head body so that only a part of the rotary tip is exposed, It is possible to prevent the blood vessel wall from being damaged when the blood vessel is rotated in the blood vessel even if it moves inside the blood vessel.

Since the head body is formed in a spiral shape, the thrombus formed on the blood vessel wall can be removed while moving inside the blood vessel.

The head module may be connected to the body module by connecting the first connection part C-1 to the second connection part C-2 of the body module.

At this time, the first connection part C-1 and the second connection part C-2 are formed so that the end of the shaft can be inserted, and they are rotated by 90 ° to be perpendicular to each other.

The four ends of the shaft are inserted and fixed in the first connection part C-1 and the second connection part C-2 by configuring the connection axis as a '+' shape as shown in FIG. 1, So that it can be rotated in four directions. That is, the connection axis is composed of a universal joint.

This also applies to the third connecting portion C-3 and the fourth connecting portion C-4 for connecting the body module and the tail module, which will be described later.

The body module has a second connecting portion C-2 and a third connecting portion C-3 at both ends thereof.

A rod connecting the second connecting portion C-2 and the third connecting portion C-3 is connected, and a self-expandable stent is wrapped around the rod.

In addition, a stent cover is formed on the outer side of the stent so as to be helical. When the MHMM moves, it is possible to move the body module which is not formed in a screw-like spiral shape. Also, .

The tail module includes a fourth connecting portion C-4 connected to the third connecting portion C-3 of the body module, and a rear portion of the fourth connecting portion C-4 includes a screw- Body. A stent driving unit is formed on the rear side of the tail body.

At this time, the stent driving unit is driven by an external magnetic force, and a shaft is formed at each end, inserted into a ring formed in the tail body of the tail module, and rotated about the axis.

That is, the stent driving unit is composed of a magnet, and a stent releasing cord is connected to the shaft, so that the stent is connected to the stent cover. Thus, as the stent driver rotates, the stent is wound and the stent cover can be moved from the body module to the tail module.

As such, when the stent cover is moved to the tail module, the stent is inflated and bulky because of the restriction, thereby preventing the blood vessel from being stuck due to the support of the thrombus-removed blood vessel.

The magnet driving of the stent driving part is the same as the driving principle of the rotary tip described in the specification of the present invention, but uses a relatively slow rotating magnetic field rather than the rotary tip.

The movement of the MHMM within the blood vessel is illustrated in FIG. 2 of the accompanying drawings. FIG. 2 is a diagram showing a motion of a multi-module helical magnetic milling robot according to the present invention in a blood vessel and a schematic structure (b) of an MHMM. FIG.

The rotary tip of the head module is driven by an external rotating magnetic field (ERMF) shown in Fig. 2, in which the magnet of the rotary tip is driven.

The rotary tip of this head module can rotate along the axis of the spiral body body and the rotary tip as shown in Fig.

FIG. 3 shows a multi-module helical magnetic milling robot according to the present invention, in which (a) shows a rotary head mounted on a head module attached to an end, (b) shows a head module (C) shows the geometric configuration of the universal joint connecting the two adjacent modules of the MHMM.

At this time, since the magnetic moment (m) used in the rotary tip always coincides with the applied magnetic field based on the magnetic torque equation, the ERMF shown in FIG. 3 (b) can be expressed by the following equation.

That is, the following formula (1) is for spirally moving the head module forward or backward along the axis P of the head body.

Where B ₀ is the size of the ERMF, ω is the angular velocity, U is the unit vector of the vertical of P, and δ is the angle of the rotary tip from P.

Equation (1) is used to control the direction of the head module when? Is 0 (static magnetic field) and? Is not 90 占.

Therefore, ERMF (ω ≠ 0, δ ≠ 0) can simultaneously control the direction and rotational motion of the head module.

When it is assumed that any number of additional modules are connected in series by the universal joints to the head module to constitute the MHMM as described above, the geometrically bent tube can be configured as shown in Fig. 2 (a).

At this time, if the head module is spirally rotated by the ERMF, the remaining modules on the rear side of the head module are simultaneously rotated along the head module rotating in a spiral manner.

For example, two unit vectors rotating with respect to the k-th module connected to the k-th universal joint and the k + 1-th module and r _k and r _{k + 1} rotating with respect to the _{k +} Can be defined as (c) of Fig.

These vectors because it keeps always a right angle to each other during the rotation _{(r k · r k +1 =} 0) k + angular displacement of the first module of the angular relationship between (k and k + 1) are the Euler angles (Euler angles) and rotation Can be derived as the following equation (2) using the rotation matrices.

Where k and k + 1 are the angles between the kth module and the k + 1th module. At this time, the angular displacement of the k-th module can be expressed by the head module angular position (? ₁ ) by the following equation (3).

Based on this, the angular velocity and acceleration of the k-th module can be expressed by the angular velocity and acceleration of the head module by calculating the first and second time derivatives of Equation (2), respectively.

Also, it can be seen that the rotational motion of each module is non-linearly related to the other module through [Equation 2] and [Equation 3].

(Ω ₁ , ω ₂ and ω ₂₎ of the angular velocity of the head module, the body module and the tail module with respect to the change of Ø _{k, k + 1} for a given constant angular velocity (ω ₁ = 2π rad / s ? ₃ ), and the changes in the accelerations? ₁ ,? ₂ and? ₃ can be calculated as shown in FIG.

FIG. 4 shows that, when all the Ø _{k and k + 1} are 0, the angular velocity and the acceleration of each module are constant but vary during rotation as the order of Ø _{k, k + 1} and module (k) increases. That is, the angular velocity faster than the head module through FIG. 4 can increase this variation.

FIG. 4 is a graph showing changes in angular velocity and acceleration of a head module, a body module and a tail module according to the degree of change of Ø _{k, k + 1} , Appeared to be unstable during rotation.

This may cause rattling or shaking during rotation of the MHMM, which may result in undesirable pressure on the robot body and the tube wall.

Hence, Equation (3) is used to determine appropriate operating conditions such as the number of modules, the curvature of the tube and the speed of the navigation so that the MHMM can be operated in a stable and safe manner.

Various experiments have been carried out to verify the multi-module helical magnetometer according to the present invention having the above-described structure.

First, a magnetic navigation system (MNS) is constructed to generate and control various external rotating magnetic fields (ERMF) (see FIG. 5 (a)).

The MNS consists of three pairs of uniform coils (Helmholtz coils in the x-axis, uniform saddle coils in the y-axis, and uniform saddle coils in the z-axis), and the input current of the coils can be independently controlled simultaneously on the control panel.

In addition, a flow generator with a maximum flow rate of 1000 cc / min was installed in the MNS to establish an extracorporeal beating flow environment.

In addition, MHMM was made of ultraviolet curable acrylic plastic using a three-dimensional printing technique based on a multi-jet molding (see (d), (e) and (f) of FIG. 5).

The magnet was applied to a rotary tip using an NdFeB magnet, having a magnetization of 955,000 A / m, a thickness of 2 mm, and an inner diameter of 2.5 mm and an outer diameter of 5 mm.

The rotary tip is covered with a bump whose outer diameter is repeated with irregularities, and can generate an unclogging motion which is operated by the ERMF.

The experimental method was first investigated in a straight glass tube filled with static water having an inner diameter of 10 mm in order to investigate the hydrodynamic thrust of the MHMM and the head module alone.

At this time, the ERMF is set to B ₀ = 10mT, P = [100] ^T , δ = 90 ° and 50π rad / s (25Hz) It was possible to generate the helical navigation operation at the moving speed.

However, MHMM was expected to have a relatively larger propulsion-to-weight ratio because the MHMM was two times heavier than the head module only and the helical thread area was three more, (Fig. 5 (b) and Fig. 5 (c)).

As expected, the angular velocity of the ERMF required to maintain the vertical equilibrium position of MHMM was measured at 59 π rad / s (25 Hz) when B ₀ = 10 mT, P = [100] ^T and δ = 90 °, The angular velocity of the ERMF required for only the head module was measured to be much higher than 110 rad / s.

Also, as shown in FIG. 6, the MHMM showed a spiral search motion in a vein flow simulating a human cardiovascular system.

The angular velocity required to maintain the current position of the MHMM is 36π rad / s (see FIG. 6) when the water flow rate is 300 cc / min and the pulsation frequency is 1.2 Hz in a horizontal bifurcated glass tube 10 mm in diameter 18Hz).

6, the average moving speed of the MHMM located at the outlet of the tube is 8 mm / s when the B ₀ = 10 mT, P = 100, ^T , ω = 50 π rad / s and δ = 90 ° in Step 1 of FIG. It travels spirally along the x-axis and reaches a two-pronged point.

와 δ=45°로 바뀌었을 때, 하부 분지로 이동하였다(STEP 2).After that, the MHMM determines that P and δ of ERMF are

And δ = 45 °, it moved to the lower branch (STEP 2).

At a faster ERMF (ω = 80π rad / s), the MHMM can perform unclogging at the point of clogging (STEP 3). In this case, the tail module of the MHMM was arranged along the x-axis (Ø _2,3 = 30 °) due to the relatively short lower branch, and rattling occurred during the rotation movement. It can be seen that the ruggedness of the ERMF increases strongly as the angular velocity increases.

및 [100]^T로 순차적으로 변화시킴으로써 생성되었다.Then, the MHMM moves to the back of the bifurcation point again by the inversion of the ERMF used in STEP 2 as in STEP 4, and the additional navigation operation of the MHMM to move the MHMM again as in STEP 5 and 6 is performed by the ERMF P To

And [100] ^T , respectively.

Thus, if the MHMM is operated within stable working conditions, the circular MHMM is expected to be able to effectively generate navigation and unclogging operations in curved tubes that are simply operated by the ERMF.

It is obvious that the present invention is not limited to the structure of the drawings, as it is possible to design variously within the technical scope of the present invention.

Claims (9)

In a multi-module helical magnetometer (MHMM)
Wherein each module is connected by a universal joint, wherein a rotary tip provided at the tip of the head module is driven by an external rotary magnetic field (ERMF), and a head module and a tail module including a spiral- Wherein the robot is capable of moving within the blood vessel.
The method according to claim 1,
The MHMM,
A head module, a body module, and a tail module,
And first connecting portions C-1 through C-4 for connecting the universal joints to ends of the respective modules,
The first to fourth connection portions C-1 to C-
And a direction perpendicular to the rotation of the adjacent ones by 90 [deg.].
The method of claim 2,
The body module includes:
A compressed stent is formed on one side,
Wherein the stent cover is formed in a spiral shape for interrupting the compression of the stent to the outside of the stent,
Wherein the stent is inflated when the stent cover is removed.
The method of claim 3,
The tail module,
And a stent driving unit composed of a magnet coupled axially to the rear end,
The stent driving unit includes:
Wherein the stent cover is connected to the stent cover via a shaft thereof so that the stent cover is moved from the body module to the tail module when the stent driver is driven.
The method of claim 4,
Wherein when the stent is inflated as the stent cover is removed from the body module, the expanded stent supports the inner wall of the blood vessel from which the thrombus has been removed by the rotary tip.
The method according to claim 1,
The rotary tip includes:
NdFeB-based magnets are used, wherein the magnets have a magnetization of 955,000 A / m, a thickness of 2 mm, and an inner diameter and an outer diameter of 2.5 mm and 5 mm are used. .
The method according to claim 1,
Wherein the ERMF is derived by the following equation.

(Where B ₀ is the magnitude of the ERMF, ω is the angular velocity, U is the unit vector perpendicular to P, and δ is the angle of the rotary tip from P).
The method of claim 7,
When the head module is spirally rotated by the ERMF, the body module and the tail module simultaneously rotate along the head module,
Two unit vectors rotating with respect to any one module k and the next module k + 1 and r _k and r _{k +1} rotating with respect to the k + 1th module maintain a right angle to each other,
Wherein r _k and r _{k +1} are derived using the Euler angles and the rotation matrix as shown in the following equation.

The method of claim 8,
, And the displacement of any one of the modules (k) is expressed by an angular position (? ₁ ) by the following equation.

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