Patent Application
20160346042
The present invention relates to a tubular endoprosthesis designing apparatus, a tubular endoprosthesis manufacturing method, and a tubular endoprosthesis designing program.
As a stent graft employed in stent graft implantation according to conventional techniques, a stent graft is known configured to have an opening (fenestration, side hole) in its tubular wall (see Patent documents 1 and 2, for example). In a case in which there is an aneurysm in the vicinity of an orifice of a branched vessel, by placing a stent graft having such an opening at such a lesion, such an arrangement is capable of blocking the flow of blood to the aneurysm without inhibiting the flow of blood to the branched vessel.
The following documents are referred to:
Japanese Patent Application Laid Open No. 2010-227486
Japanese Patent Application Laid Open No. 2013-52282
In the process of manufacturing such a stent graft having an opening, before the stent graft implantation, first, two-dimensional CT (Computed Tomography) images are acquired for the blood vessels of the patient, for example. Subsequently, three-dimensional blood vessel images are constructed by means of software based on the two-dimensional blood vessel images thus acquired. Next, a stent graft having an optimal structure is designed according to the blood vessel structure in a region in which the stent graft is to be implanted, based on the two-dimensional blood vessel images and the three-dimensional blood vessel images. Furthermore, the stent graft is designed to have an opening at the optimal position such that the stent graft does not inhibit the blood that flows through the branched vessel after the stent graft is implanted at a lesion.
However, it is needless to say that there are individual differences in blood vessel structure. That is to say, there is a difference in the position and the shape of an aneurysm among patients. Accordingly, it is difficult to design the optimal position of such an opening without a doctor's many years of experience or otherwise technical support based on experience.
Such a problem can also occur in other kinds of tubular endoprostheses in addition to such a stent graft, examples of which include a synthetic graft having no stent framework.
One or more embodiments of the present invention provide a technique for allowing the designer to easily design a tubular endoprosthesis having an opening at an optimal position in its tubular wall.
The present inventors have conducted strenuous investigations in order to achieve the aforementioned purpose. As a result, the present inventors have found that there is a difference in the position of a sheath after it is inserted into a blood vessel, according to the shape of curvature of the blood vessel in a region in which the tubular endoprosthesis is to be implanted. This has a large effect on the implantation position (position deviation) of the tubular endoprosthesis. In order to solve such a problem, it has been found that, by simulating the insertion of the sheath into the blood vessel after the information with respect to the shape of curvature of the blood vessel is acquired, and by determining the position of the opening based on the simulation results, such an arrangement is capable of determining an optimal position of the opening formed in the tubular wall of the tubular endoprosthesis in a simple manner. It should be noted that description will be made regarding an embodiment of the present invention with reference to the corresponding symbols. However, the present invention is not restricted to such an embodiment.
One or more embodiments of the invention proposes a tubular endoprosthesis designing apparatus (which corresponds to the tubular endoprosthesis designing apparatus 1 shown in
Such an arrangement is capable of determining, in a simple manner, the optimal position for each opening to be formed in the tubular endoprosthesis.
First, description will be made below regarding the outline of the present invention.
The present inventors constructs a blood vessel model based on the blood vessel images, and designed and formed a stent graft based on the same blood vessel images. Furthermore, the present inventors conducted an experiment of implanting the stent graft thus formed in the blood vessel model thus formed. As a result of the experiment, the present inventors have found that, as the degree of twisting of the blood vessel in the vicinity of the branched vessel becomes larger, it becomes more difficult to provide alignment between an opening (fenestration, side hole) of the stent graft and the orifice of the branched vessel.
Accordingly, the present inventors have accumulated research on the cause of the mechanism in which, as the degree of twisting of a blood vessel in the vicinity of a branched vessel becomes larger, it becomes more difficult to provide alignment between the opening of the stent graft and the orifice of the branched vessel. As a result of these investigations, the present inventors have found that, in a case of employing a sheath formed in a shape that is curved in a predetermined single direction, or otherwise a sheath formed such that it can be curved in a predetermined single direction, as a sheath for housing a stent graft, there is a difference in the trajectory of the sheath when it passes through a blood vessel according to the degree of twisting of the blood vessel. This has a large effect on the implantation position (position deviation) of the stent graft.
Description will be made below regarding the “twisting of the blood vessel” described above. In a case in which the “blood vessel” is the thoracic aorta, in some cases, the blood vessel is curved not only in a U shape (inverted U shape) on a virtual plane, but also curved in a front-back direction (forward direction or otherwise backward direction), i.e., in a direction that is orthogonal to the direction in which the blood vessel is curved on the virtual plane. The aforementioned “twisting of the blood vessel” represents the shape of curvature of the blood vessel in the front-back direction. That is to say, in some cases, in addition to a curve in a virtual plane, a given blood vessel has another curve in a direction having a vector component that is orthogonal to the virtual plane. That is to say, the “twisting of the blood vessel” represents a curve of the blood vessel in a direction having a vector component that is orthogonal to the aforementioned virtual plane.
In a case in which a blood vessel has relatively slight twisting (in a case in which there is almost no twisting in the blood vessel), the sheath is passed through the interior of the blood vessel along its center axis. Accordingly, a stent graft deployed from the sheath is implanted within the blood vessel such that the edge of the stent graft with greater curvature approximately matches the edge of the blood vessel with greater curvature.
In contrast, an experiment conducted by the present inventors shows that, in a case in which there is relatively severe twisting in a blood vessel, the sheath does not always pass through the blood vessel along its center axis. That is to say, it has been found that, in some cases, the sheath deviates from the center axis of the blood vessel when it passes through a region in which the blood vessel has severe twisting. In a case of employing a stent graft having curvature in a predetermined single direction, and in a case in which such a stent graft is housed in the sheath such that the direction of curvature of the stent graft matches the direction of curvature of the sheath, in some cases, the stent graft is deployed from the sheath in a state in which it has deviated from the center axis of the blood vessel. In this case, there is a low probability that the stent graft will be implanted within the blood vessel such that the edge of the stent graft with greater curvature matches the edge of the blood vessel with greater curvature.
In a case in which a blood vessel has relatively slight twisting, before an opening is formed in the tubular wall of the stent graft, for example, the distance between the edge of the blood vessel with greater curvature and the orifice of the branched vessel (which corresponds to the “shortest distance L1” described later) is calculated, and the position of the opening is determined such that the distance thus calculated matches the distance between the edge of the stent graft with greater curvature and the opening (which corresponds to the “shortest distance Lf” described later). That is to say, the position of the opening is determined so as to satisfy the relation Lf=L1. In a case in which there is no factor that has an effect on the implantation of the stent graft, such an arrangement is capable of providing alignment between the opening and the orifice of the branched vessel in a relatively simple manner.
In contrast, in a case in which there is relatively severe twisting in the blood vessel, because of the cause described above, with such an arrangement in which the position of the opening is determined based on only a single condition of the distance between the edge of the stent graft with greater curvature and the opening matching the distance between the edge of the blood vessel with greater curvature and the orifice of the branched vessel, it is difficult to provide alignment between the opening and the orifice of the branched vessel.
The present inventors have found that, by simulating the insertion of the sheath into a blood vessel based on information with respect to the degree of twisting of the blood vessel, and by determining the position of the opening based on the simulation result, such an arrangement is capable of determining, in a simple manner, an optimal position of the opening to be formed in the tubular wall of the stent graft.
Next, detailed description will be made below regarding an embodiment of the present invention with reference to the drawings. It should be noted that an existing component or the like may be substituted as appropriate for each component employed in the present embodiment. Also, various modifications may be made, examples of which include a combination with other existing components. Accordingly, description of the present embodiment is by no means intended to restrict the technical scope of the present invention described in the appended claims.
The tubular endoprosthesis designing apparatus 1 supports the design of a stent graft 6. The tubular endoprosthesis manufacturing apparatus 2 supports the manufacture of the stent graft 6 based on the design made by the tubular endoprosthesis designing apparatus 1.
The tubular endoprosthesis designing apparatus 1 includes a three-dimensional model generating unit 10, a simulation unit 20, and an opening position determination unit 30. In one embodiment, the three-dimensional model generating unit 10, the simulation unit 20, and the opening position determination unit 30 are each configured as a software-implemented component provided by a computer 200 shown in
The hard disk 230 stores an operating system, a program (tubular endoprosthesis design program) to be used to execute a tubular endoprosthesis designing method for designing the stent graft 6, a correction value table (see Table 1 described later), and the like. It should be noted that the hard disk 230 may preferably be configured as a non-temporary recoding medium. For example, instead of the hard disk 230, non-transitory storage medium such as EPROM, flash memory, or the like, or otherwise a CD-ROM may be employed.
The CPU 210 uses the memory 220 as appropriate so as to read out the data stored in the hard disk 230 and to execute a program or calculation.
Returning to
The stent graft 6 is formed such that it is curved in an arched shape, i.e., is curved in a predetermined direction. Furthermore, openings 61, 62, and 63 each having a predetermined shape are formed in the tubular wall of the stent graft 6. The openings 61 through 63 are formed such that they respectively face the orifices of the brachiocephalic artery A10, the left common carotid artery A20, and the left subclavian artery A30, each of which branch from the thoracic aorta A1.
The sheath 5 is formed such that it is curved in an approximately J shape, i.e., such that it is curved in a predetermined direction. The sheath 5 is configured as a tubular member formed of a flexible material. The stent graft 6 is housed in the sheath 5 in a state in which the direction in which the stent graft 6 is curved matches the direction in which the sheath 5 is curved.
Returning to
The opening position determination unit 30 determines the position of each of the openings 61 through 63 to be formed in the tubular wall of the stent graft 6, based on the simulation result obtained by the simulation unit 20 and the information with respect to the shape of twisting of the thoracic aorta A1 in a region in which the stent graft 6 is to be implanted. Description will be made below with reference to
Description will be made below regarding the “twisting of the blood vessel” with reference to the thoracic aorta A1 as an example shown in
The “edge line R1 of the thoracic aorta A1” represents the line that passes through the side of the thoracic aorta A1 with the greatest curvature. The “edge line R2 of the sheath 5” represents the line that passes through the side of the sheath 5 with the greatest curvature. The “edge line R3 of the stent graft 6” represents the line that passes through the side of the stent graft 6 with the greatest curvature. Here, the “line that passes through the side with the greatest curvature” represents a line that passes through the outermost point of each slice portion that forms a curved object.
First, as shown in
Next, the opening position determination unit 30 determines a position deviation L2 between the edge line R1 of the thoracic aorta A1 in a region in which the stent graft 6 is to be implanted and the edge line R2 of the sheath 5 in a state in which the sheath 5 is inserted into this region. Specifically, the opening position determination unit 30 calculates, as the position deviation L2, the shortest distance between the edge line R1 of the thoracic aorta A1 and the edge line R2 of the sheath 5 in the vicinity of the aforementioned edge point P1.
Next, the opening position determination unit 30 acquires a correction value L4 that corresponds to the position deviation L2 with reference to a correction value table shown in the following Table 1.
It should be noted that the aforementioned position deviation L2 becomes larger according to an increase in the degree of twisting of the thoracic aorta A1. That is to say, the position deviation L2 indirectly represents the degree of twisting of the thoracic aorta A1. Accordingly, the position deviation L2 can be used by the opening position determination unit 30 as the information with respect to the shape of twisting of the thoracic aorta A1 in a region in which the stent graft 6 is to be implanted.
Next, the opening position determination unit 30 substitutes the aforementioned shortest distance L1 and the aforementioned correction value L4 into the following Expression (3), so as to calculate a shortest distance Lf between the edge line R3 of the stent graft 6 and an edge point Q1 of the opening 61. The edge point Q1 represents a reference point defined on the edge of the opening 61. Also, a tangent line RQ1 represents a tangent line to the edge of the opening 61 defined such that it passes through the edge point Q1, and such that is in parallel with the edge line R3 of the stent graft 6 (see
[Expression 3]
Lf=L1+L4 (3)
Description will be made below with reference to
As shown in
In a case in which the edge line R2 of the sheath 5 deviates from the edge line R1 of the thoracic aorta A1 in the negative direction along the Z axis and in a case in which the shortest distance L1 is greater than the absolute value of the correction value L4 as shown in
In a case in which the edge line R2 of the sheath 5 deviates from the edge line R1 of the thoracic aorta A1 in the negative direction along the Z axis and in a case in which the shortest distance L1 is smaller than the absolute value of the correction value L4 as shown in
The tubular endoprosthesis manufacturing apparatus 2 performs membrane member preparation step (Step S1), following which the flow proceeds to Step S2. In the membrane member preparation step, the tubular endoprosthesis manufacturing apparatus 2 prepares a membrane member to be used as a graft. It should be noted that the membrane member thus prepared is configured as a membrane sheet, and is cut in a predetermined size according to a standard specification, for example.
The tubular endoprosthesis designing apparatus 1 performs opening position determination step (Step S2), following which the flow proceeds to Step S3. In the opening position determination step, the tubular endoprosthesis designing apparatus 1 determines the position of each of the openings 61 through 63 to be formed in the membrane member prepared in Step S1, details of which will be described later with reference to
The tubular endoprosthesis manufacturing apparatus 2 performs opening formation step (Step S3), following which the flow proceeds to Step S4. In the opening formation step, the tubular endoprosthesis manufacturing apparatus 2 forms each of the openings 61 through 63 in the membrane member prepared as a sheet member in Step S1 at a position determined in Step S2 such that they conform to the standard specification. Examples of a method for forming each of the openings 61 through 63 include punching using a press die.
The tubular endoprosthesis manufacturing apparatus 2 performs graft formation step (Step S4), following which the flow proceeds to Step S5. In the graft formation step, the tubular endoprosthesis manufacturing apparatus 2 joins both ends of the membrane sheet member in which the openings 61 through 63 have been formed in Step S3, so as to form a cylindrical graft. Examples of such a method for joining both ends of the membrane sheet member include bonding using an adhesive agent, pressure bonding, welding, and suturing using thread.
The tubular endoprosthesis manufacturing apparatus 2 performs graft fixing step (Step S5), thereby completing the manufacturing of the stent graft 6 shown in
The tubular endoprosthesis designing apparatus 1 instructs the three-dimensional model generating unit 10 to perform a first step (Step S11), following which the flow proceeds to Step S12. In the first step, the tubular endoprosthesis designing apparatus 1 instructs the three-dimensional model generating unit 10 to generate a three-dimensional model AA of a blood vessel in which the stent graft 6 is to be implanted.
The tubular endoprosthesis designing apparatus 1 instructs the simulation unit 20 to perform a second step (Step S12), following which the flow proceeds to Step S13. In the second step, the tubular endoprosthesis designing apparatus 1 instructs the simulation unit 20 to simulate a state in which the sheath 5 is inserted into the three-dimensional model AA generated in Step S11.
The tubular endoprosthesis designing apparatus 1 instructs the opening position determination unit 30 to perform a third step (Step S13), following which the flow returns to Step S3 shown in
The tubular endoprosthesis designing apparatus 1 as described provides the following advantages.
The tubular endoprosthesis designing apparatus 1 instructs the simulation unit 20 to simulate a state in which the sheath 5 is inserted into the three-dimensional model AA generated by the three-dimensional model generating unit 10. Furthermore, the tubular endoprosthesis designing apparatus 1 instructs the opening position determination unit 30 to determine each of the positions of the openings 61 through 63 to be formed in the tubular wall of the stent graft 6, based on the simulation result obtained by the simulation unit 20 and the information with respect to the shape of twisting of the thoracic aorta A1 in a region in which the stent graft 6 is to be implanted. Thus, even if there is an effect on the implantation position (deviation) of the stent graft 6 due to individual differences in the shape of twisting of the thoracic aorta A1 among patients, such an arrangement is capable of determining an optimal position for each of the openings 61 through 63 giving consideration to this effect due to such individual differences. Such an arrangement is capable of determining, in a simple manner, the optimal position for each of the openings 61 through 63 to be formed in the stent graft 6.
Furthermore, in the tubular endoprosthesis designing apparatus 1, the opening position determination unit 30 uses the information with respect to the shape of twisting of the thoracic aorta A1 (information with respect to the shape of curvature of the thoracic aorta A1 in a region in which the stent graft 6 is to be implanted). Thus, the tubular endoprosthesis designing apparatus 1 is capable of determining an optimal position for each of the openings 61 through 63 to be formed in the tubular wall of the stent graft 6 giving consideration to the shape of twisting of the thoracic aorta A1.
Moreover, the tubular endoprosthesis designing apparatus 1 is configured to determine each of the positions of the openings 61 through 63 based on the position relation between the edge line R1 of the thoracic aorta A1 in a region in which the stent graft 6 is to be implanted and the edge line R2 of the sheath 5 in a state in which it is inserted into this region. Thus, such an arrangement is capable of determining an optimal position for each opening regardless of the degree of twisting (degree of curvature) of the blood vessel.
Moreover, the tubular endoprosthesis designing apparatus 1 is capable of determining an optimal position for each of openings 61 through 63 in a relatively simple manner using the aforementioned Table 1 and Expression (3).
With the tubular endoprosthesis manufacturing system 100 including the tubular endoprosthesis designing apparatus and the tubular endoprosthesis manufacturing apparatus 2 as described above, such an arrangement is capable of manufacturing the stent graft 6 having the openings 61 through 63 each formed at an optimal position.
The opening position determination unit 30A determines each of the positions of the openings 61 through 63 to be formed in the tubular wall of the stent graft 6, based on the simulation result obtained by the simulation unit 20 and the information with respect to the shape of twisting of the thoracic aorta A1 in a region in which the stent graft 6 is to be implanted, in the same manner as the opening position determination unit 30. It should be noted that the opening position determination unit 30A uses the Expression (4) described below instead of the aforementioned Table 1 and Expression (3).
Specifically, first, the opening position determination unit 30A instructs the simulation unit 20 to calculate, as a simulation result, the shortest distance L1 between the edge line R1 of the thoracic aorta A1 in a region in which the stent graft 6 is to be implanted and the edge point P1 of the orifice of the brachiocephalic artery A10, in the same manner as the opening position determination unit 30.
Next, the opening position determination unit 30A instructs the simulation unit 20 to calculate, as a simulation result, the position deviation L2 between the edge line R1 of the thoracic aorta A1 in a region in which the stent graft 6 is to be implanted and the edge line R2 of the sheath 5 in a state in which it is inserted into this region, in the same manner as the opening position determination unit 30.
In a case in which there is relatively severe twisting in the thoracic aorta A1, in some cases, such an arrangement leads to misalignment, i.e., deviation between the edge line R3 of the stent graft 6 and the edge line R2 of the sheath 5 after the stent graft 6 is deployed from the sheath 5.
In order to solve such a problem, as a next step, the opening position determination unit 30A instructs the simulation unit 20 to calculate, as a simulation result, a position deviation L3 between the edge line R2 of the sheath 5 in a state in which it is inserted into a region in which the stent graft 6 is to be implanted and the edge line R3 of the stent graft 6 in a state in which it is implanted after it is deployed to this region from the sheath 5.
As a method for calculating the position deviation L3, for example, a state of the stent graft 6 may be simulated from the time point at which it is deployed from the sheath up to the time point at which the stent graft 6 is implanted. In the simulation, the position deviation may be calculated between the edge line R2 of the sheath 5 and the edge line R3 of the stent graft 6 in a state in which the stent graft 6 is implanted (distance between the edge line R2 of the sheath 5 and the edge line R3 of the stent graft 6 along an arc defined on a virtual cross-sectional plane that includes a section of the sheath 5 and a section of the stent graft 6 and that is orthogonal to the center axis of the thoracic aorta A1). As an another method for obtaining the position deviation L3, a relation expression between the position deviation L3 and the position deviation L2 may be derived based on measurement data, and the position deviation L3 may be obtained using the relation expression thus derived.
The opening position determination unit 30A substitutes the aforementioned shortest distance L1 and the aforementioned position deviations L2 and L3 into the following Expression (4), so as to calculate the shortest distance Lf between the edge line R3 of the stent graft 6 and the edge point Q1 of the opening 61.
[Expression 4]
Lf=L1+L2+L3 (4)
With the tubular endoprosthesis designing apparatus 1A described above using Expression (4) instead of the aforementioned Table 1 and Expression (3), such an arrangement provides the same effects as those provided by the tubular endoprosthesis designing apparatus 1.
As the information with respect to the shape of twisting of the thoracic aorta A1 in a region in which the stent graft 6 is to be implanted, the tubular endoprosthesis designing apparatus 1A instructs the opening position determination unit 30A to use the following two position relations calculated as the simulation results by the simulation unit 20. One of the aforementioned two position relations is the position relation between the edge line R1 of the thoracic aorta A1 in a region in which the stent graft 6 is to be implanted and the edge line R2 of the sheath 5 in a state in which it is inserted into this region. The other of the aforementioned two position relations is the position relation between the edge line R2 of the sheath 5 in a state in which it is inserted into a region in which the stent graft 6 is to be implanted and the edge line R3 of the stent graft 6 in a state in which it is implanted in this region after it is deployed from the sheath 5. With such an arrangement, each of the positions of the openings through 63 is determined using the aforementioned two position relations. Thus, such an arrangement is capable of determining a further optimal position for each of the openings 61 through 63 regardless of the degree of twisting (degree of curvature) of the thoracic aorta A1.
Detailed description has been made with reference to the drawings regarding the embodiments of the present invention. However, such a specific configuration is not restricted to the aforementioned embodiments. Also, various kinds of design changes may be made, which are encompassed within the technical scope of the present invention.
For example, description has been made above in the aforementioned embodiments with reference to the stent graft as an example of a tubular endoprosthesis. However, the application of the present invention is not restricted to such an arrangement. Also, the present invention is applicable to other kinds of tubular endoprostheses to be implanted in the body, examples of which include a synthetic graft and the like. It should be noted that examples of such a stent graft include a stent graft for the abdominal aorta and a stent graft for the thoracoabdominal aorta, in addition to the stent graft for the thoracic aorta. Also, such a stent graft is not restricted to an arrangement in which a stent is arranged within a graft (a so-called endoskeletal structure). Also, such a stent graft may be configured as an arrangement in which a stent is arranged on the outer side of a graft (a so-called exoskeletal structure). Also, such a stent graft may be configured as an arrangement in which a graft is adhered to each of the inner face and the outer face of the stent.
Description has been made in the aforementioned embodiments regarding an aneurysm as an example of a lesion. However, the lesion to which the present invention is applicable is not restricted to such an aneurysm. For example, the present invention is applicable to other kinds of lesions such as varicose veins, narrowed blood vessels, etc. It should be noted that examples of the aforementioned aneurysm include an aortic aneurysm, cerebral aneurysm, peripheral aneurysm (popliteal aneurysm, iliac aneurysm, etc.). Examples of the aforementioned varicose veins include a varix of the lower extremity.
Description has been made in the aforementioned embodiments regarding the stent graft 6 configured such that it is curved in a predetermined direction. However, the present invention is not restricted to such an arrangement. Also, the stent graft 6 may be configured to have a straight structure (linear structure) as a basic structure and to have a portion that can be curved in a predetermined direction. Also, the stent graft 6 may be configured to have a portion that can be curved in various directions.
Description has been made in the aforementioned embodiments regarding the sheath 5 configured such that it is curved in a predetermined direction. However, the present invention is not restricted to such an arrangement. Also, the sheath 5 may be configured to have a straight structure (linear structure) as a basic structure and to have a portion that can be curved in a predetermined direction.
Description has been made in the aforementioned embodiments regarding an arrangement in which the three-dimensional model AA is generated by the three-dimensional model generating unit 10 provided as a software component by means of the computer 200. That is to say, the three-dimensional model AA is configured as a virtual model on the computer. However, the present invention is not restricted to such an arrangement. For example, the three-dimensional model AA may be configured as a model formed of a material by means of a 3D printer.
Description has been made in the aforementioned embodiments regarding an arrangement in which, after the position is determined for each of the openings 61 through 63, the openings 61 through 63 are each formed in the membrane sheet member at the corresponding position thus determined. However, the present invention is not restricted to such an arrangement. Also, the openings 61 through 63 may each be formed in a cylindrical graft at a predetermined position. In this case, position alignment may be made between the cylindrical graft and the stent based on the shortest distance Lf calculated using the aforementioned Expression (3) or otherwise Expression (4), so as to fix the graft to the stent.
Description has been made in the aforementioned embodiments regarding an arrangement in which, in the determination of the position of the opening 61, the edge point P1, which is defined as a single reference point on the orifice of the brachiocephalic artery A10, is used as the reference position of the orifice of the brachiocephalic artery A10. However, the present invention is not restricted to such an arrangement. Also, multiple edge points defined on the orifice of the brachiocephalic artery A10 may be used as the reference positions. In this case, the same number of edge points may be defined on the edge of the opening 61, and the multiple edge points thus defined may be employed as the reference positions of the opening 61, instead of employing the single edge point Q1 defined on the edge of the opening 61.
Description has been made in the aforementioned embodiments regarding an arrangement in which, in determination of the position of the opening 61, the edge point P1 defined on the edge of the orifice of the brachiocephalic artery A10 is employed as a reference position of the orifice of the brachiocephalic artery A10. However, the present invention is not restricted to such an arrangement. Also, a central position of the orifice of the brachiocephalic artery A10 may be employed as the reference position. In this case, a central portion of the opening 61 may be employed as its reference position instead of employing the edge point Q1 defined on the edge of the opening 61.
Description has been made in the aforementioned embodiments regarding an arrangement in which a single reference position is defined for each of the three branched vessels, and a single reference position is defined for each of the openings 61 through 63. Subsequently, the opening position is determined for each of the openings 61 through 63. However, the present invention is not restricted to such an arrangement. For example, a single reference position may be defined for all three branched vessels in the same manner as in a coordinate system. In this case, after a single reference position is determined for all the openings 61 through 63, the opening positions of the openings 61 through 63 may be determined at the same time.
Also, in the aforementioned first embodiment, the correction value table may be updated as appropriate.
Description has been made in the aforementioned embodiments regarding an arrangement in which the tubular endoprosthesis manufacturing apparatus 2 performs the membrane member preparation step, the opening formation step, the graft formation step, and the graft fixing step, as an example. However, such steps may be performed manually without employing the tubular endoprosthesis manufacturing apparatus. Description has been made in the aforementioned embodiments regarding an arrangement in which the tubular endoprosthesis designing apparatus 1 or 1A performs the opening position determination step (first step through third step). Also, an arrangement may be made without involving such a tubular endoprosthesis designing apparatus. For example, in the first step, such a three-dimensional model of the blood vessels may be formed as a transparent or translucent model (mock-up). Also, the following second and third steps may be performed using the three-dimensional model thus formed.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2015111501 | Jun 2015 | JP | national |
