KR20220090605A - Screw For Implantable Medical Device - Google Patents

Abstract

A screw for an implantable medical device is disclosed.
The disclosed screw for implantable medical device is to be implanted and fixed to the bone, the body portion is positioned in the fastening direction to be viewed through the medical device image, and a groove is formed to guide the insertion of the fastening device; 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

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 displays a position clearly without distortion of an MRI image will be.

Implantable medical devices are medical devices that are implanted in the human body to replace or assist part of body functions, deliver electrical stimulation, or inject medicines. With the increase, the need is increasing. The field of application of implantable medical devices is, for example, implantable cardiac pacemaker or implantable cardiac defibrillator for patients with heart disease, anticancer drug for patients undergoing chemotherapy and chronic disease, and implantable medicine injection that can constantly inject painkillers, etc. There may be a pump or the like.

Currently, in order to increase the therapeutic effect of brain-related diseases, treatment methods through repeated oral and intravenous administration over a continuous period are widely used. However, the existing method has limitations in that it may be difficult to take the drug itself if the digestive system is weakened, a number of side effects may be induced due to the systemic circulation of the therapeutic agent, and the physical pain and economic burden of the patient following inpatient treatment and administration of the therapeutic agent is large. .

On the other hand, the direct administration method to the brain has the advantage that the effect is excellent compared to the existing method, but there are few side effects due to the systemic circulation of the drug. In the intracerebral direct 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 point, which is the hippocampus, for treatment. However, there is a difficulty in that drugs targeting the brain must pass through the blood-brain barrier (BBB). And, in order to increase the therapeutic effect, it is necessary to repeatedly administer to the correct target point.

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

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

On the other hand, when inserting into the skull using general implantable medical device screws in animal experiments, osseointegration was difficult, the image was distorted during MRI, and problems were found that the tightening was weak. There is a need.

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

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

In order to achieve the above object, in the screw for implantable medical device according to the present invention, the screw is implanted and fixed to the bone, and is located in the fastening direction and has a groove to guide the insertion of the fastening device so as to be transparent for imaging of the medical device. 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 Expressions 1 and 2 below.

<Condition 1>

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

<Condition 2>

L ₁ is the length of the body, and L ₂ is the length of the head.

At least one pressure reducing groove is formed at the end of the body portion, and the screw thread is tapered to the end, and the following conditional expression 3 may be satisfied.

<Condition 3>

L ₁ means the length of the body part, L ₃ means the length of the portion in which the pressure reducing groove is formed.

The screw thread may satisfy the following Conditional Equation 4.

<Condition 4>

P means the pitch of the threads formed on the outer peripheral surface of the body part, A ₁ means the angle at which the threads are formed.

a fixing part for pre-fastening by fixing the body part with respect to the fastening mechanism even before the fastening state that the head part is forcibly fitted into the protrusion or groove provided at the end of the fastening mechanism to guide in the fastening direction; and intersecting each other horizontally and vertically with respect to the fixing groove to be connected to each other, and may include an intersecting portion for inserting the body portion in the fastening direction during rotational motion by fastening the fastening mechanism.

Each of the fixing part and the intersection part may satisfy the following conditional expression 3 (3).

<Conditional Expression 5>

L ₄ means the depth of the crossing portion, and D ₃ means the size of the outer diameter of the fixing portion.

The fixing part may include a guide part that is formed to satisfy the following conditional expression 6 and guides the insertion direction of the fastener.

<Conditional Expression 6>

Here, A ₂ refers to the angle of the inner peripheral surface of the hem of the fixing part 150 .

Each of the head part and the body part may be made of titanium or polyether ether ketone.

a contrast agent contained in the groove to be transparent for imaging of medical devices; and a leak prevention cap for preventing the contrast medium from leaking to the outside.

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

After filling the inside of the body with the contrast agent before insertion into the bone, it can be cooled to solidify, or the contrast agent and the solid agent can be mixed and filled and then irradiated with UV to solidify.

The screw for implantable medical device according to the present invention has the effect of being easily fastened without damage when the screwdriver is fastened because the fastening part of the head is inclined at a predetermined angle to the left and right.

In addition, the screw for an implantable medical device according to the present invention can be clearly marked without distorting the image on images such as X-rays and MRIs as the contrast medium is filled in the inner space of the fastening part.

In addition, the screw for implantable medical device according to the present invention is made of polyether ether ketone (PEEK), so that even after long-term implantation, bone fusion is good, the implant has stability in the living body, and the fastening force of the implantable medical device is excellent.

In addition, since the screw for implantable medical device according to the present invention further includes a leak-proof cap in the body portion, there is an advantage in that the image is clearly displayed without the contrast medium leaking to the outside.

1 is a cross-sectional view showing a state of injecting a drug 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;
Fig. 4 is a cross-sectional view taken along line A-A' of Fig. 2;
5 is a cross-sectional view taken along line B-B' 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 illustrated by exaggerating or simplifying a part 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 to be inserted into the bone 1, and “horizontal direction” may mean a transverse direction crossing from the “fastening direction”. In addition, terms such as "first", "second", "one side", and "other side" used in the present invention are used to distinguish one component from another component, and each component is the term are not limited by

1 is a cross-sectional view illustrating a state in which a drug is injected after finding and installing a target point in a patient's skull 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 , the drug injection device 10 may be inserted when performing an operation on a patient P related to a brain disease requiring drug injection into the brain. Here, the brain disease may be related to, for example, brain tumor, stroke, Alzheimer's, a dementia disease, Parkinson's, a mental disease, depression, schizophrenia, and the like. The drug injection device 10 punctures and implants the skull 1 of the patient P, and the scalp (subcutaneous layer) 3 is placed in the position of the temporal bone and parietal bone of the skull 1 in a 'U' shape. can be cut

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

The main body 11 is implanted in 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. have. The movable part 13 is inserted into the main body 11 and has a spherical shape with an open upper part and can be switched to a target point 7 that is a lesion in the brain parenchyma (5). In the guide tube 14, an injection needle (N) for injecting brain disease-related drugs therein may be inserted. Here, the injection needle (N) may accommodate, for example, a trocar needle, a needle for inspection, and the like therein. However, without being limited thereto, various surgical instruments and equipment, for example, navigation probes, stimulation leads, ablation probes or catheters, injection or fluid delivery devices, biopsy needles, extraction tools, etc. may be inserted to perform diagnostic and/or therapeutic procedures. can run

In addition, by using the drug injection device 10, various therapeutic agents 9, which are various brain disease-related drugs, may be injected. For example, dementia-related chemicals such as the amyloid hypothesis (substances that inhibit the production of β-amyloid protein), Aβ protein aggregation inhibitors, tau aggregation inhibitors cholinase inhibitors, NMDA receptors or antagonists, cholinergic precursors, antioxidants, diabetes drugs, etc. Drugs, human umbilical cord blood cells, human umbilical cord blood-derived mesenchymal stem cells, neural stem cells, stem cells such as bone marrow stem cells, drugs for treating psychiatric diseases such as Parkinson’s, depression, schizophrenia, brain tumors and stroke-related therapeutic drugs, etc. may be included. .

Here, the screw 100 may include at least two coupling the upper body 11 and the upper body fixing part 15 to the skull 1 .

On the other hand, the screw 100 is not limited only to fastening the drug injection device 10 to the skull 1, and implanted into the bones of the body, for example, a cardiac pacemaker, an implantable defibrillator, and implantation. It is also possible to fasten the type drug infusion pump, etc.

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

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

The head part 110 may be positioned at one end of the body part 150 and mounted on the implantable medical device.

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

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

L ₁ is the length of the body, and L ₂ is the length of the head.

If it deviates from the lower limit of Equation 1, since the diameter of the body 150 becomes larger than the diameter of the head 110, it may fall into a hole to be fastened without being mounted after fastening.

In addition, when the upper limit of Equation 1 is exceeded, the head part 110 may be relatively large, so that the force is weaker than that of the body part 150 , so that the fixing force is lowered, and stable fastening may not be possible.

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

On the other hand, if it is outside the lower limit of Equation 2, it may be difficult to fix and support the implanted body 150 as the length of the head 110 is relatively long.

In addition, if it is outside the upper limit of Equation 2, as the body portion 150 is relatively long, it presses out of the skull 1 to the cerebral 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 part 110 and the body part 150 to form an implantable medical device. can be fixed

At least one pressure reducing groove 155 is formed at the end of the body 150 and the thread is tapered to the end, and the following Equation 3 may be satisfied.

L ₁ means the length of the body part, L ₃ means the length of the portion in which the pressure reducing groove is formed.

When 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 the bone is implanted, the internal contact area expands and the implantation torque and pressure increase, so that 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 grafting.

In addition, when it is outside the upper limit of Equation 3, it is possible to increase the pressure on the bone tissue during implantation as the implantable medical device screw 100 in which the pressure reducing groove 155 is hardly formed. When transplanted for a long time as described above, bone tissue may be damaged, causing inflammation, and in severe cases, adverse effects of transplantation may occur.

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

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

P denotes the pitch of the threads 157 formed on the outer peripheral surface of the body 150, and A ₁ denotes the angle at which the threads 157 are formed.

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

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

If the angle (A ₁ ) of Equation 4 is out of the lower limit of the range, it may have a rectangular screw shape. Accordingly, the fastening time may be delayed or the fastening may not be easy. Even if it is fastened and fixed, it may be loosened finely even by a small external vibration, and the function of the screw may be lost. In addition, when the angle (A ₁ ) of Equation 4 is out of the upper limit of the range, the cross-section of the screw thread 157 in contact with the bone is sharp and there is a risk of causing damage to the bone tissue during rotational movement when inserted in the fastening direction.

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

Referring to FIG. 3 , the head part 110 may include a fixing part 115 and an intersection part 111 . The fixing part 115 may be press-fitted into a projection or groove provided at the end of the fastener. That is, the fixing part 115 can be pre-fastened by fixing the body part 150 with respect to the fastening mechanism even before the fastening state guiding the fastening direction in the fastening direction without magnetic force (magnet). Accordingly, when using the fixing unit 115, it is easy to implant the implantable medical device into the bone and the time can be shortened.

The intersecting part 111 is formed to cross each other horizontally and vertically around the fixing part 150 to be connected to each other.

In addition, the cross section 111 is press-fitted with the fastening mechanism can be rotated. At this time, the rotational motion of the fastening mechanism may be converted to linear motion of the implantable medical device screw 100 in the fastening direction. In addition, the cross section 111 is not limited to a cross shape, but may have various shapes such as a straight shape, a curved shape, etc. so that the screw 100 for implantable medical device rotates smoothly with respect to the fastening mechanism.

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

L ₄ denotes the depth of the crossing portion 111 , and D ₃ denotes 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 crossing part 111 deepens, and when it exceeds the upper limit of Equation 5, the size of the outer diameter of the fixing part 150 is As the cross section 111 becomes relatively large, rotational movement with the fastening mechanism may become difficult.

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

The fixing part 150 is formed to satisfy the following Equation 6 and may include a guide part for guiding the insertion direction of the fastener.

Here, A ₂ refers to the angle of the inner peripheral surface of the hem of the fixing part 150 .

When the lower limit of Equation 6 is exceeded, the head part 110 may be bent outwardly due to the pressing force when the fastener is fastened to the fixing part 150 , and the outer end of the fixing part 150 may be cracked. . In addition, when the upper limit of Equation 6 is exceeded, since both ends of the fixing part 150 may be too wide apart, it may not be possible to hold the protrusion of the fastening mechanism, so that the fastening may be difficult. Accordingly, when Equation 6 is satisfied, since the fixing part 150 has a shape that becomes narrower toward the lower end, it is easy to fasten by holding the protrusion of the fastening mechanism during fastening, and can be tentatively coupled with one fastening.

Meanwhile, each of the head part 110 and the body part 150 may be made of titanium or polyether ether ketone (PEEK). However, the present invention is not limited thereto, and may be manufactured by variously applying a material having body graft bonding properties.

5 is a cross-sectional view taken along line B-B' of FIG. 3 .

Referring to FIG. 5 , a contrast agent 170 that is contained in the groove 130 according to an embodiment of the present invention to be transparent for imaging of a medical device and a leak prevention cap that prevents 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 implantable medical device including the contrast agent 170 may be solidified by cooling after filling the body portion 150 with the contrast agent 170 before insertion into the bone. Accordingly, the screw 100 for implantable medical devices may contain only the contrast agent 170 without the leakage preventing cap 190 . It is not limited to such a modified example, and as another modified example, the contrast agent 170 and the solid agent may be mixed and filled and then irradiated with UV to be solidified.

The above-described embodiments are merely exemplary, and various modifications and equivalent other embodiments are possible by those of ordinary skill in the art to which the present invention pertains. Therefore, the true technical protection scope of the present invention will have to be determined by the technical idea of the invention described in the claims.

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

Claims (11)

In the screw for implantable medical device,
It is implanted and fixed to the bone, the body portion is located inside the fastening direction so as to be transparent to the imaging of the medical device, the groove is formed to guide the insertion of the fastening mechanism; and
An implantable medical device screw positioned at one end of the body part and including a head part mounted on the implantable medical device. The method of claim 1,
The body portion and the head portion,
An implantable medical device screw that satisfies at least one of the following Conditional Expressions 1 and 2.
<Condition 1>

D ₁ means the size of the outer diameter of the body portion, D ₂ means the size of the head portion outer diameter.
<Condition 2>

L ₁ is the length of the body, and L ₂ is the length of the head. 3. The method of claim 2,
The body part,
An implantable medical device screw that has at least one pressure reducing groove formed at the end and the thread is tapered to the end, and satisfies condition 3 below.
<Condition 3>

L ₁ means the length of the body part, L ₃ means the length of the portion in which the pressure reducing groove is formed. 4. The method of claim 3,
The screw thread is
An implantable medical device screw that satisfies the following Conditional Expression 4.
<Condition 4>

P means the pitch of the threads formed on the outer peripheral surface of the body part, A ₁ means the angle at which the threads are formed. According to claim 1,
The head part,
a fixing part for pre-fastening by fixing the body part with respect to the fastening mechanism even before the fastening state which is forcibly fitted into the protrusion or groove provided at the end of the fastening mechanism to guide in the fastening direction; and
A screw for an implantable medical device comprising an intersecting portion formed to cross each other horizontally and vertically with respect to the fixing groove to be connected to each other, and to insert the body portion in the fastening direction when the fastening mechanism is fastened to rotate. 6. The method of claim 5,
Each of the fixing part and the crossing part satisfies the following condition 3 for an implantable medical device screw.
<Conditional Expression 5>

L ₄ means the depth of the crossing portion, and D ₃ means the size of the outer diameter of the fixing portion. 7. The method of claim 6,
The fixing part,
A screw for an implantable medical device including a guide part that is formed to satisfy the following conditional expression 6 and guides the insertion direction of the fastener.
<Conditional Expression 6>

Here, A ₂ refers to the angle of the inner peripheral surface of the hem 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. 9. The method according to any one of claims 1 to 8,
a contrast agent contained in the groove to be transparent for imaging of medical devices; and
An implantable medical device screw further comprising a leak-proof cap for preventing the contrast medium from leaking to the outside. 10. The method of claim 9,
The contrast agent,
An implantable medical device screw comprising a group consisting of at least one of barium sulfate and sodium carboxymethyl cellulose. 11. The method of claim 10,
An implantable medical device screw, characterized in that the contrast medium is filled inside the body before insertion into the bone and then solidified by cooling or filled with a mixture of the contrast agent and the solid agent and then solidified by irradiating UV.

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