KR102530796B1 - Screw For Implantable Medical Device - Google Patents

Abstract

A screw for an implantable medical device is disclosed.
The disclosed screw for an implantable medical device is implanted and fixed to a bone, and includes a body portion in which a groove is formed to guide insertion of a fastening mechanism and to be positioned in a fastening direction and to be transparent to medical device imaging; and a head portion positioned at one end of the body portion and mounted on the implantable medical device.

Description

Screw for implantable medical device {Screw For Implantable Medical Device}

The present invention relates to a screw for an implantable medical device, and more particularly, to a screw for an implantable medical device that is easy to fasten, has a strong fixing force, and allows the MRI image to be clearly displayed without distortion. will be.

Implantable Medical Devices are medical devices that are implanted into the human body to replace or assist part of bodily functions, transmit electrical stimulation, or inject medicines. With the increase, the need is increasing. The field of application of implantable medical devices is, for example, implantable pacemaker or implantable defibrillator for patients with heart disease, and implantable medicine injection that can inject anticancer drugs and painkillers for patients with chemotherapy and chronic diseases. There may be pumps and the like.

Currently, in order to increase the therapeutic effect of brain-related diseases, a method of treatment through repeated oral administration and intravenous administration for a continuous period is widely used. However, existing methods have limitations in that when the digestive system is weakened, it may be difficult to take the drug itself, many side effects may be caused by systemic circulation of the therapeutic agent, and the patient's physical pain and economic burden due to hospitalization and administration of the therapeutic agent are great. .

On the other hand, the method of direct administration to the brain has an advantage in that the effect is superior to that of the conventional method, but there are few side effects due to the systemic circulation of the drug. In the direct intracerebral administration method, for example, in the case of a patient with dementia, a therapeutic agent such as a chemical drug or stem cell may be directly administered to a target site, which is the hippocampus. However, drugs targeting the brain have difficulties in passing through the blood-brain barrier (BBB). In addition, in order to increase the therapeutic effect, it is necessary to repeatedly administer to the exact target site.

The drug is directly injected into the brain, and the effect can be maximized and the side effects of the drug can be minimized with only a small amount of injection. Therefore, intracerebral drug injection direct administration technology will become a new paradigm in the dementia treatment market.

Referring to Patent Literatures 1 and 2, a screw to be inserted into the skull is disclosed. First, Patent Document 1 relates to an intracerebral drug injection device, which functions to fasten an implantable medical device to the skull by inserting a screw. In addition, Patent Document 2 relates to a system for stereotactic access, and relates to a bone screw including an introducer positioned below the stereotactic access device and accommodated through a guide channel.

On the other hand, in animal experiments, when inserting screws for implantable medical devices into the skull, it was difficult to osseointegrate, images were distorted during MRI scans, and weak tightening was found. There is a need.

Publication No. 2019-0049183 (2019.05.09.) Publication No. 2016-01113180 (2016.09.28.)

The present invention was devised in view of the above points, and the purpose of the present invention is to provide a screw for medical devices in which images on MRI and X-ray images are not distorted and the position is clearly displayed, and the fixation force is maintained for a long time after the procedure. .

In order to achieve the above object, in the implantable medical device screw according to the present invention, it is implanted and fixed to the bone, is located in the fastening direction and has a groove formed to guide the insertion of the fastening mechanism and to be transparent to the medical device image taking. body part; and a head portion positioned at one end of the body portion and mounted on the implantable medical device.

The body part and the head part may satisfy at least one of Conditional Expression 1 and Conditional Expression 2 below.

<conditional expression 1>

D ₁ means the size of the outer diameter of the body part, and D ₂ means the size of the outer diameter of the head part.

<conditional expression 2>

L ₁ means the length of the body part, and L ₂ means the length of the head part.

At least one pressure reducing groove is formed at the end of the body portion and the thread is tapered to the end, and Conditional Expression 3 below may be satisfied.

<conditional expression 3>

L ₁ means the length of the body part, and L ₃ means the length of the part where the pressure reducing groove is formed.

The screw thread may satisfy Conditional Expression 4 below.

<conditional expression 4>

P denotes a pitch of threads formed on the outer circumferential surface of the body, and A ₁ denotes an angle at which the threads are formed.

The head part is forcibly fitted into the protrusion or groove provided at the end of the fastening mechanism to guide the fastening direction, and fixes the body to the fastening mechanism even before fastening to allow temporary fastening; And it may include an intersection portion that is formed by crossing each other horizontally and vertically around the fixing portion, and allows the body portion to be inserted in the fastening direction during rotation by fastening the fastening mechanism.

Each of the fixing part and the crossing part may satisfy Conditional Expression 3 below.

<conditional expression 5>

L ₄ means the depth of the intersection part, and D ₃ means the size of the outer diameter of the fixing part.

The fixing part may include a guide part that is formed to satisfy Conditional Expression 6 below and guides a direction in which the fastening mechanism is inserted.

<conditional expression 6>

Here, A ₂ means the angle of the bottom inner circumferential surface of the fixing part 150 .

Each of the head part and the body part may be made of titanium or polyetheretherketone.

a contrast agent contained in the groove and projected through medical device imaging; and a leak prevention cap preventing leakage of the contrast medium to the outside.

The contrast medium may include a group consisting of at least one of barium sulfate and sodium carboxymethyl cellulose.

Before inserting into the bone, the inside of the body part is filled with the contrast medium and then cooled and solidified, or the contrast medium and the solid agent may be mixed and filled and then UV irradiated to solidify the body.

In the screw for an implantable medical device according to the present invention, since the fastening portion of the head part is inclined at a predetermined angle to the left and right, there is an effect of being easily fastened without damage when fastened with a screwdriver.

In addition, the screw for an implantable medical device according to the present invention can clearly display the position of the screw without distorting the image on images such as X-ray and MRI as the contrast medium is filled in the internal space of the fastening part.

In addition, the screw for an implantable medical device according to the present invention is made of polyetheretherketone (PEEK) and has a biotransplantation stability that allows good osseointegration even after long-term implantation, and has an excellent fastening force for implantable medical devices.

In addition, the screw for an implantable medical device according to the present invention has an advantage in that the body portion further includes a leak-proof cap, so that the image is clearly displayed without leakage of the contrast agent to the outside.

1 is a cross-sectional view showing a state in which a drug is injected after finding and installing a target point in the skull of a patient using a drug injection device fastened to a screw for an implantable medical device according to an embodiment of the present invention.
Figure 2 is a side view showing a screw for an implantable medical device according to an embodiment of the present invention.
3 is a plan view of a head unit according to an embodiment of the present invention;
4 is a cross-sectional view taken along line A-A' of FIG. 2;
5 is a cross-sectional view taken along line BB′ of FIG. 3;

Hereinafter, a screw for an implantable medical device according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. Here, the accompanying drawings are partially exaggerated or simplified for convenience and clarity of explanation and understanding of the configuration and operation of the technology, and each component does not exactly match the actual size.

The term "fastening direction" used in the present invention means a direction in which the bone 1 is inserted, and "transverse direction" may mean a transverse direction crossing from the "fastening direction". In addition, the terms "first", "second", "one side" and "other side" used in the present invention are used to distinguish one component from other components, and each component is the term are not limited by

1 is a cross-sectional view showing a state in which a drug is injected after finding and installing a target point in the skull of a patient using a drug injection device fastened to a screw for an implantable medical device according to an embodiment of the present invention.

Referring to FIG. 1 , a drug injection device 10 may be inserted when performing a procedure on a brain disease-related patient P requiring drug injection into the brain. Here, the brain disease may be related to, for example, brain tumor, stroke, Alzheimer's disease as a dementia disease, Parkinson's disease as a mental disease, depression, schizophrenia, and the like. The drug injection device 10 is a scalp (subcutaneous layer) 3 in a 'U' shape at positions such as the temporal bone and parietal bone of the skull 1 in order to perforate and implant the skull 1 of the patient P. can be incised.

In addition, the drug injection device 10 is composed of a main body 11, a movable part 13, a guide tube 14, a main body fixing part 15, a sealing part 16, and a movable stopper 18.

The main body 11 is implanted into the skull 1, and the upper end of the main body 11 is located between the scalp 3 and the skull 1, and the lower end of the main body 11 can be inserted into the skull 1 and positioned. there is. The movable part 13 is inserted into the body 11 and has a spherical shape with an open top, and can change direction to a target point 7, which is a lesion in the brain parenchyma 5. Guide tube 14 may be inserted into the injection needle (Needle) (N) for injecting drugs related to brain disease therein. Here, the injection needle N may accommodate, for example, a trocar needle or a test needle therein. However, it is not limited thereto, and various surgical instruments and equipment such as navigation probes, stimulation leads, ablation probes or catheters, injection or fluid transfer devices, biopsy needles, extraction tools, etc. may be inserted to perform diagnostic and/or therapeutic procedures. can run

In addition, using the drug injection device 10, various therapeutic agents 9 that are drugs related to various brain diseases can be injected. For example, dementia-related chemicals such as amyloid hypotheses (substances that inhibit β-amyloid protein production), Aβ protein aggregation inhibitors, tau aggregation inhibitors, cholinease inhibitors, NMDA receptors or antagonists, cholinergic precursors, antioxidants, and diabetic drugs Drugs, human umbilical cord blood cells, human umbilical cord blood-derived mesenchymal stem cells, stem cells such as neural stem cells and bone marrow stem cells, drugs for treating mental disorders such as Parkinson's disease, depression, and schizophrenia, and drugs for treating brain tumors and strokes may be included. .

Here, the screw 100 may include at least two screws for fastening the upper part of the main body 11 and the upper part of the main body fixing part 15 to the skull 1.

On the other hand, the screw 100 is not limited to fastening the drug injection device 10 to the skull 1, and implantable medical devices such as pacemakers, implantable cardiac defibrillators, implants in bones in the body It is also possible to fasten and fix a type drug infusion pump.

2 is a side view showing a screw for an implantable medical device according to an embodiment of the present invention.

Referring to FIG. 2 , a screw 100 for an implantable medical device according to an embodiment of the present invention may include a body portion 150 and a head portion 110 .

The body portion 150 is implanted and fixed to the bone, and may be positioned inside in a fastening direction and formed with a groove 130 to guide insertion of a fastening mechanism (not shown) so as to be transparent for medical device imaging.

The head part 110 is located at one end of the body part 150 and can be mounted on an implantable medical device.

The body part 150 and the head part 110 may satisfy at least one of Conditional Expression 1 and Conditional Expression 2 below.

D ₁ means the size of the outer diameter of the body part, and D ₂ means the size of the outer diameter of the head part.

L ₁ means the length of the body part, and L ₂ means the length of the head part.

If the lower limit of Equation 1 is exceeded, since the diameter of the body portion 150 is larger than the diameter of the head portion 110, it may fall into a hole where it is fastened without being mounted after fastening.

In addition, when the upper limit of Equation 1 is exceeded, the head portion 110 may be relatively large, and thus the force is weakened compared to the body portion 150, thereby reducing the fixing force and making stable fastening impossible.

Accordingly, when the condition range of Equation 1 is satisfied, the implantable medical device screw 100 can fix the implantable medical device and improve implantation stability and fixing force.

On the other hand, when the lower limit of Equation 2 is exceeded, it may be difficult to fixally support the body part 150 to be transplanted as the length of the head part 110 becomes relatively long.

In addition, when the upper limit of Equation 2 is exceeded, as the body portion 150 is relatively long, it escapes from the skull 1 and compresses the brain parenchyma 5, which may cause side effects after transplantation.

Therefore, when the condition range of Equation 2 is satisfied, the implantable medical device screw 100 is implanted in the skull 1 by having an appropriate ratio between the head portion 110 and the body portion 150 to obtain an implantable medical device. can be fixed.

The body portion 150 has at least one pressure reducing groove 155 formed at the end and a screw thread tapered to the end, and may satisfy Equation 3 below.

L ₁ means the length of the body part, and L ₃ means the length of the part where the pressure reducing groove is formed.

If the lower limit of Equation 3 is exceeded, since the pressure reducing groove 155 is designed to be relatively longer than the length of the body 150, the function of the implantable medical device screw 100 may be lost and the fixing force may be weakened. That is, when implanted in the bone, the internal contact area is expanded, and the implantation torque and pressure increase, and tissue cells may be destroyed. At this time, if the implantation torque is too high, necrosis of bone tissue cells occurs and there is a high probability of failure of important osseointegration after bone transplantation.

In addition, when the screw 100 for an implantable medical device in which the pressure reducing groove 155 is hardly formed when the upper limit value of Equation 3 is exceeded, the pressure on the bone tissue during implantation can be increased. In this way, when transplanted for a long time, bone tissue may be damaged and inflammation may be caused, and severe transplant surgery side effects may occur.

Therefore, if the condition range of Equation 3 is satisfied, when the implantable medical device screw 100 having the pressure reducing groove 155 is implanted in the bone, the pressure damaging the bone tissue can be relatively weakened to minimize bone damage. there is.

In addition, the thread 157 may satisfy Equation 4 below.

P means the pitch of the thread 157 formed on the outer circumferential surface of the body portion 150, and A ₁ means the angle at which the thread 157 is formed.

If it is out of the lower limit of the pitch (P) range of Equation 4, the fastening time may be delayed. In addition, when the upper limit of the pitch (P) range of Equation 4 is out of range, even if it is fastened and fixed, it may be loosened finely even by small external vibration and the function of the screw may be lost.

Therefore, when the range of the pitch (P) of Equation 4 is satisfied, it can be easily implanted in bone, easily coupled to an implantable medical device, and wear due to tolerance can be somewhat reduced.

If the angle (A ₁ ) of Equation 4 is out of the lower limit, it may have a rectangular screw shape. Therefore, the fastening time may be delayed or fastening may not be easy. Even if it is fastened and fixed, the function of the screw may be lost due to fine loosening even with a small external vibration. In addition, when the angle (A ₁ ) of Equation 4 is out of the upper limit, the cross section of the screw thread 157 in contact with the bone is sharp and may cause damage to bone tissue during rotation when inserted in the fastening direction.

3 is a plan view of the head part 110 according to an embodiment of the present invention, and FIG. 4 is a cross-sectional view of FIG. 2 taken along line A-A'.

Referring to FIG. 3 , the head portion 110 may include a fixing portion 115 and an intersection portion 111 . The fixing part 115 may be force-fitted into a protrusion or groove provided at an end of the fastening mechanism. That is, the fixing part 115 may temporarily fasten the body 150 to the fastening mechanism even in a pre-fastening state in which it guides in the fastening direction without magnetic force (magnet). Therefore, when using the fixing unit 115, it is easy to implant the implantable medical device into the bone and the time required can be shortened.

The crossing portion 111 is formed by crossing each other horizontally and vertically around the fixing portion 150, and the body portion 150 can be inserted in the fastening direction during rotation by fastening the fastening mechanism.

In addition, the crossing portion 111 may perform a rotational movement by being force-fitted with the fastening mechanism. At this time, the rotational motion of the fastening mechanism may be converted so that the screw 100 for the implantable medical device linearly moves in the fastening direction. In addition, the crossing portion 111 is not limited to a cross shape, and may have various shapes such as a straight line shape and a curved shape so that the screw 100 for an implantable medical device rotates smoothly with respect to the binding mechanism.

Referring to FIG. 4 , each of the fixing part 150 and the crossing part 111 may satisfy Equation 5 below.

L ₄ means the depth of the intersection part 111 , and D ₃ means the size of the outer diameter of the fixing part 150 .

When the lower limit of Equation 5 is exceeded, the function of the fixing part 150 may be lost as the depth of the intersection 111 increases, and when the upper limit of Equation 5 is exceeded, the size of the outer diameter of the fixing part 150 As it becomes relatively large, rotational movement of the crossing portion 111 with the fastening mechanism may become difficult.

Therefore, when the condition range of Equation 5 is satisfied, the head part 110 has both the function of being force-fitted with the fastening mechanism to rotate the intersection part 111 and the function of temporarily coupling with the fastening mechanism of the fixing part 150. As it has, it can be easily fastened and fixed.

The fixing part 150 may include a guide part that is formed to satisfy Equation 6 below and guides the insertion direction of the fastening mechanism.

Here, A ₂ means the angle of the bottom inner circumferential surface of the fixing part 150 .

When the lower limit of Equation 6 is exceeded, when the fastening mechanism is fastened to the fixing part 150, the head part 110 may be bent outward due to the pressing force, and the outer end of the fixing part 150 may be broken. . In addition, when the upper limit of Equation 6 is exceeded, since both ends of the fixing part 150 may be too open, it may be difficult to fasten because the protrusion of the fastening mechanism cannot be held. Therefore, when Equation 6 is satisfied, since the fixing part 150 has a shape that becomes narrower towards the lower end, it is easy to fasten by holding the protrusion of the fastening mechanism during fastening, and it can be temporarily coupled with one fastening.

Meanwhile, each of the head part 110 and the body part 150 may be made of titanium or polyetheretherketone (PEEK). However, it is not limited thereto, and may be manufactured by applying various materials having body implant bonding properties.

5 is a BB′ cross-sectional view of FIG. 3 .

Referring to FIG. 5 , a contrast agent 170 contained in the groove 130 according to an embodiment of the present invention to be projected on medical device imaging and a leak-proof cap preventing the contrast agent 170 from leaking to the outside ( 190) may be further included.

The contrast agent 170 may include a group consisting of at least one of barium sulfate and sodium carboxymethyl cellulose.

On the other hand, as a modified example of the present invention, the screw 100 for an implantable medical device containing a contrast medium 170 may be solidified by filling the inside of the body portion 150 with the contrast medium 170 before being inserted into the bone and then cooling. Accordingly, the screw 100 for an implantable medical device may contain only the contrast medium 170 without the leakage prevention cap 190 . It is not limited to this modification, and in another modification, the contrast medium 170 and the solid agent may be mixed and filled, and then irradiated with UV to solidify.

The above embodiments are only exemplary, and various modifications and other equivalent embodiments may be made therefrom by those skilled in the art. Therefore, the true technical protection scope of the present invention should be determined by the technical spirit of the invention described in the claims.

P: patient N: needle
1: skull (bone) 3: scalp (subcutaneous layer)
5: brain parenchyma 7: target site
9: drug or treatment 10: drug injection device
11: main body 13: movable part
14: guide tube 15: main body fixing part
16: sealing part 18: movable stopper
100: screw for implantable medical device 110: head
111: crossing part 115: fixing part
130: Groove 150: Body
155: pressure reducing groove 170: contrast agent
190: leak-proof cap

Claims (11)

In the screw for implantable medical devices,
A body portion that is implanted and fixed to the bone, is located in the fastening direction, is transparent to medical device imaging, and has a groove formed to guide the insertion of the fastening mechanism; and
A head portion located at one end of the body portion and mounted on the implantable medical device;
the head part,
a fixing unit that is forcibly fitted into a protrusion or groove provided at an end of the fastening mechanism and guides the fastening direction in a fastening direction by fixing the body to the fastening mechanism so as to be temporarily fastened; and
A screw for an implantable medical device comprising an intersection portion formed by intersecting each other horizontally and vertically with the fixing portion as a center, and including an intersection portion for fastening the fastening mechanism to allow the body portion to be inserted in the fastening direction during rotational movement. According to claim 1,
The body part and the head part,
A screw for an implantable medical device that satisfies at least one of Conditional Expression 1 and Conditional Expression 2 below.
<conditional expression 1>

D ₁ means the size of the outer diameter of the body part, and D ₂ means the size of the outer diameter of the head part.
<conditional expression 2>

L ₁ means the length of the body part, and L ₂ means the length of the head part. According to claim 2,
The body part,
At least one pressure reducing groove is formed at the end and the screw thread is formed to be tapered to the end, and a screw for an implantable medical device that satisfies the following conditional expression 3.
<conditional expression 3>

L ₁ means the length of the body part, and L ₃ means the length of the part where the pressure reducing groove is formed. According to claim 3,
The screw thread,
A screw for an implantable medical device that satisfies Conditional Expression 4 below.
<conditional expression 4>

P denotes a pitch of threads formed on the outer circumferential surface of the body, and A ₁ denotes an angle at which the threads are formed. delete According to claim 1,
A screw for an implantable medical device, wherein each of the fixing part and the crossing part satisfies Conditional Expression 3 below.
<conditional expression 5>

L ₄ means the depth of the intersection part, and D ₃ means the size of the outer diameter of the fixing part. According to claim 6,
The fixing part,
A screw for an implantable medical device including a guide portion formed to satisfy the following conditional expression 6 and guiding a direction in which a fastening mechanism is inserted.
<conditional expression 6>

Here, A ₂ means the angle of the bottom inner circumferential surface of the fixing part 150 . According to claim 1,
Each of the head part and the body part,
A screw for implantable medical devices made of titanium or polyetheretherketone. The method of any one of claims 1 to 4 and 6 to 8,
a contrast agent contained in the groove and projected through medical device imaging; and
A screw for an implantable medical device further comprising a leak-proof cap preventing the contrast medium from leaking to the outside. delete According to claim 9,
A screw for an implantable medical device, characterized in that the contrast medium is filled into the body before being inserted into the bone and then cooled and solidified, or the contrast medium and solid are mixed and filled and then irradiated with UV to solidify.

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