Abstract:
The present invention provides a leaflet sizer comprising first and second commissure indication parts to be contacted with two commissures of a cardiac valve, the first and second commissure indication parts being movable relative to each other.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a Continuation of International Application No. PCT/JP2015/086525, filed on Dec. 28, 2015, which claims the benefit of Japanese Application No. 2015-001193 filed on Jan. 6, 2015, the contents of each of which are hereby incorporated by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to a leaflet sizer for measuring the size of a cardiac valve. The leaflet sizer is used at the time of, for example, aortic valvuloplasty or aortic valve reconstruction where for a cardiac valve, a leaflet material is formed from an artificial membrane or a biological membrane. 
       BACKGROUND 
       [0003]    JP 5106019 B2 (Patent Literature 1 described below) discloses a leaflet forming instrument. This leaflet forming instrument has plural leaflet sizers and a template. An example of the leaflet sizer is illustrated in  FIG. 2  of this literature. That is, the leaflet sizer in this literature has sizer blocks and handles, and an arc surface formed by cutting a column by an angle corresponding to a center angle of commissure parts is formed in the sizer block (claim  2 ). A stylus portion that positions both end parts of the arc surface in the commissure parts is provided in the sizer block. As illustrated in  FIG. 1  of the literature, the leaflet forming instrument disclosed in this literature has a shape in which the sizer blocks in plural sizes are respectively connected to the handles. 
         [0004]    Aortic valvuloplasty is introduced in, for example, Ozaki, S. “Aortic valvuloplasty using patient&#39;s own cardiac membrane” JINKOU ZOUKI Vol. 39, Issue 3, 2010, p.p. 157-161 (Non Patent Literature 1). In this literature, as described above, a leaflet sizer having sizer blocks and handles is also used (for example, see  FIG. 2 ). 
       CITATION LIST 
       [0005]    Patent Literature 1: JP 5106019 B2 
         [0006]    Non Patent Literature 1: Ozaki, S. “Aortic valvuloplasty using patient&#39;s own cardiac membrane” JINKOU ZOUKI Vol. 39, Issue 3, 2010, p.p. 157-161. 
         [0007]    Aortic valvuloplasty is a revolutionary medical approach. Meanwhile, the above leaflet forming instrument requires leaflet sizers in plural sizes. Even when one leaflet forming instrument includes plural leaflet sizers, about one or two leaflet sizer is used for one procedure in practice. Therefore, there is a problem that a large number of leaflet sizers become useless. 
         [0008]    The leaflet forming instrument is originally a disposable medical instrument. However, since a large number of leaflet sizers are not used at the time of a procedure as described above, there is a possibility that the leaflet forming instrument is re-used. 
         [0009]    Further, in the conventional leaflet sizer, with a sizer head formed in a fan shape, the handle is attached to a pivot part of the fan at an angle. Therefore, when the conventional leaflet sizer is inserted deep into the artery, there is a problem that the handle is touched to the anterior wall of aorta and the sizer is not easily inserted into a far part. 
         [0010]    An object of the present invention is to provide a leaflet sizer capable of preventing a situation in which the leaflet sizer is re-used. The present invention also relates to a leaflet sizer to be easily inserted into the aorta at the time of a procedure and hence the size of a leaflet is easily measured. 
       SUMMARY 
       [0011]    A first aspect of the present invention relates to one or a small number of leaflet sizer (or a leaflet sizer set) having functions of the conventional plural leaflet sizers. The leaflet sizer has first and second commissure pointing portions  11 ,  13  to be applied to two commissure parts in a cardiac valve. Thereby, the leaflet sizer can determine the size of the cardiac valve. In the leaflet sizer  15  of the first aspect of the present invention, relative positions of the first and second commissure pointing portions  11 ,  13  are variable. 
         [0012]    As an example of the leaflet sizer in which the relative positions of the first and second commissure pointing portions  11 ,  13  are variable, the leaflet sizer has a first support portion  21  supporting the first commissure pointing portion  11 , and the first support portion  21  is extendable and retractable. In this case, the leaflet sizer may further have a second support portion  23  supporting the second commissure pointing portion  13 . The second support portion  23  is also extendable and retractable. 
         [0013]    As an example of the leaflet sizer in which the relative positions of the first and second commissure pointing portions  11 ,  13  are variable, the leaflet sizer further has an indicator display portion  25  that displays an indicator corresponding to a distance of the two commissure parts when the first support portion  21  is extended or retracted. 
         [0014]    As an example of an extending and retracting function in the leaflet sizer in which the relative positions of the first and second commissure pointing portions  11 ,  13  are variable, the leaflet sizer has a leaflet sizer main body having a housing portion  27  for slidably housing the first support portion. 
         [0015]    As a preferred example of the leaflet sizer, the leaflet sizer further has a leaflet sizer main body  31  connected to the first and second commissure pointing portions  11 ,  13 , and a handle  33  connected to the leaflet sizer main body  31 , and the handle  33  exists at a position in the vicinity of one of the first and second commissure pointing portions  11 ,  13 . 
         [0016]    In another embodiment, the leaflet sizer may have a first arm  51 , a second arm  52 , and a coupling support point portion  53 . The first arm  51  and the second arm  52  cross each other around intermediate parts thereof. The coupling support point portion  53  openably and closeably couples the first and second arms  51 ,  52  at a crossing point of the first and second arms  51 ,  52 . In this embodiment, the first commissure pointing portion  11  is provided in a leading end of the first arm  51 , and the second commissure support portion  13  is provided in a leading end of the second arm  52 . In such a way, the relative positions of the first and second commissure pointing portions  11 ,  13  may be variable. 
         [0017]    In still another embodiment, the leaflet sizer may have a base portion  61 , a rod  62 , a first arm  63 , and a second arm  64 . The rod  62  is inserted into the base portion  61 . This rod  62  is capable of going forward and backward in the base portion  61  by being guided by the base portion  61 . The first arm  63  and the second arm  64  are coupled to this base portion  61 . The first and second arm portions  63  are opened and closed linked with actions of the rod  62  going forward and backward in the base portion  61 . In this embodiment, the first commissure pointing portion  11  is provided in a leading end of the first arm  63 , and the second commissure support portion  13  is provided in a leading end of the second arm  64 . In such a way, the relative positions of the first and second commissure pointing portions  11 ,  13  may be variable. 
         [0018]    A second aspect of the present invention relates to a leaflet sizer set  17  having plural leaflet sizer heads  15   a,    15   b,    15   c.  The leaflet sizer heads  15   a,    15   b,    15   c  are medical instruments respectively having first and second commissure pointing portions  11   a,    13   a  to be applied to two commissure parts in a cardiac valve for determining the size of the cardiac valve. Relative positions of the first and second commissure pointing portions are different respectively in the plural leaflet sizer heads  15   a,    15   b,    15   c.  That is, the leaflet sizer set  17  has the leaflet sizer heads in plural sizes. The plural leaflet sizers respectively have coupling holes  41   a,    41   b,    41   c  for coupling the plural leaflet sizer heads, and the plural leaflet sizer heads are integrated by a restraining body  43  passing through the coupling holes. 
         [0019]    The leaflet sizer of the first aspect of the present invention is one or a small number of leaflet sizer having the functions of the conventional plural leaflet sizers. Therefore, the number of the leaflet sizers to be unused at all but disposed can be reduced. As a result, re-use of the leaflet sizer can be prevented. 
         [0020]    In the leaflet sizer in which the handle is in the vicinity of one of the commissure support portions, the handle  33  is placed at the position in the vicinity of the aortic wall in comparison to the conventional sizer. Thus, when the sizer is inserted into the aorta, the handle is not easily touched to the anterior wall of aorta. As a result, the sizer is easily inserted into a far part of the aorta. 
         [0021]    In the leaflet sizer of the second aspect of the present invention, the plural sizers are integrated. Thus, even in a case where part of the sizers has been utilized, it is difficult to dispose only the part. Therefore, re-use of the leaflet sizer can be prevented. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]      FIG. 1  is a concept view illustrating an example of a leaflet sizer of the present invention. 
           [0023]      FIG. 2  is a concept view illustrating an example of the leaflet sizer of the present invention. 
           [0024]      FIG. 3  is a concept view illustrating an example of the leaflet sizer of the present invention. 
           [0025]      FIG. 4  is a concept view illustrating an example of the leaflet sizer of the present invention. 
           [0026]      FIG. 5  is a perspective view illustrating an example of an outer appearance of a crossing openable and closeable type leaflet sizer. 
           [0027]      FIG. 6  is an enlarged view illustrating a state where the crossing openable and closeable type leaflet sizer is closed. 
           [0028]      FIG. 7  is an enlarged view illustrating a state where the crossing openable and closeable type leaflet sizer is opened. 
           [0029]      FIG. 8  is a schematic view illustrating an action range of the crossing openable and closeable type leaflet sizer. 
           [0030]      FIG. 9  is a perspective view illustrating a state where a rod openable and closeable type leaflet sizer is closed. 
           [0031]      FIG. 10  is a perspective view illustrating a state where the rod openable and closeable type leaflet sizer is opened. 
           [0032]      FIG. 11  is a schematic view illustrating an action range of the rod openable and closeable type leaflet sizer. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0033]    Hereinafter, modes for carrying out the present invention will be described with using the drawings. The present invention is not limited to the modes to be described below but also includes corrections of the following modes appropriately done by those skilled in the art in an obvious range. 
         [0034]    A first aspect of the present invention is one or a small number of leaflet sizer having functions of the conventional plural leaflet sizers. The leaflet sizer is a known medical instrument as disclosed in Patent Literature 1 (JP 5106019 B2) and Non Patent Literature 1 (Ozaki, S. “Aortic valvuloplasty using patient&#39;s own cardiac membrane” JINKOU ZOUKI Vol. 39, Issue 3, 2010, p.p. 157-161) as described above. 
         [0035]      FIG. 1  is a concept view illustrating an example of a leaflet sizer of the present invention. As illustrated in  FIG. 1 , the leaflet sizer has first and second commissure pointing portions  11 ,  13  to be applied to two commissure parts in a cardiac valve. The first and second commissure pointing portions  11 ,  13  correspond to the stylus portion in Patent Literature 1 (JP 5106019 B2). The first and second commissure pointing portions  11 ,  13  are parts to be inserted into a cut valve ring part at the time of a procedure for respectively pointing the commissure parts positioned on both ends. By the first and second commissure pointing portions  11 ,  13 , the leaflet sizer can determine the size of a cardiac valve. In the leaflet sizer  15  of the first aspect of the present invention, relative positions of the first and second commissure pointing portions  11 ,  13  are variable. 
         [0036]    As an example of the leaflet sizer in which the relative positions of the first and second commissure pointing portions  11 ,  13  are variable, the leaflet sizer has a first support portion  21  supporting the first commissure pointing portion  11 , and the first support portion  21  is extendable and retractable. In this case, the leaflet sizer may further have a second support portion  23  supporting the second commissure pointing portion  13 . The second support portion  23  may also be extendable and retractable. The phrase “extendable and retractable” means that the relative positions of the first and second commissure pointing portions  11 ,  13  are variable. 
         [0037]    As an example of the leaflet sizer in which the relative positions of the first and second commissure pointing portions  11 ,  13  are variable, the leaflet sizer further has an indicator display portion  25  that displays an indicator corresponding to a distance of the two commissure parts when the first support portion  21  is extended or retracted. For example, in a housing portion  27 , a device that measures an end part of a leaflet sizer main body  31  existing in the housing portion  27  may be provided, and by measuring a position of the end part by this device, the relative positions of the first and second commissure pointing portions  11 ,  13  may be grasped and the grasped relative positions may be displayed on the indicator display portion  25 . 
         [0038]    As an example of an extending and retracting function in the leaflet sizer in which the relative positions of the first and second commissure pointing portions  11 ,  13  are variable, the leaflet sizer has the leaflet sizer main body  31  having the housing portion  27  for slidably housing the first support portion  21 . By the leaflet sizer main body  31  sliding inside the housing portion  27 , the relative positions of the first and second commissure pointing portions  11 ,  13  can be changed. 
         [0039]    As a preferred example of the leaflet sizer, the leaflet sizer further has the leaflet sizer main body  31  connected to the first and second commissure pointing portions  11 ,  13 , and a handle  33  connected to the leaflet sizer main body  31 . The handle  33  exists at a position in the vicinity of one of the first and second commissure pointing portions  11 ,  13 . In a case where the x coordinates of the first and second commissure pointing portions  11 ,  13  are 0 (×1) and ×2, respectively, and the x coordinate of the handle  33  is ×3, ×3 may preferably be 0 or more and 0.4×2 or less, or 0 or more and 0.3×2 or less, or 0 or more and 0.2×2 or less, or 0 or more and 0.1×2 or less. When the handle is displaced from the first commissure pointing portion  11 , the sizer is more balanced. Thus, ×3 may be 0.05×2 or more and 0.3×2 or less, or 0.1×2 or more and 0.2×2 or less. A part of the handle  33  in contact with the housing portion  27  or the leaflet sizer main body  31  may be the center of the housing body  27  or the leaflet sizer main body  31 . However, in that case, the handle is preferably inclined toward any of the first and second commissure pointing portions  11 ,  13 . 
         [0040]    As a preferred example of the leaflet sizer, a mark  29  exists in a center part of an edge part. This mark is useful for marking at the time of a procedure. 
         [0041]    In an example illustrated in  FIG. 1 , the sizer main body  31  exists in an edge part of a column. The example has a structure in which the first and second support portions  21 ,  23  are bent upward from both ends (or from the vicinity of both the ends) of the edge part. In this example, the first commissure pointing portion  11  and the first support portion  21  exist on the left side of the center of a main body part in  FIG. 1 , and the second commissure pointing portion  13  and the second support portion  23  exist on the right side of the center of the main body part in  FIG. 1 . Parts of the first and second support portions  21 ,  23  existing in the edge part are partly or entirely housed in the housing portion  27 . This example has a tubular body having an inner diameter which is the same as or larger than the outer shape of the edge part in such a manner that the housing portion  27  can house edge parts of the first and second support portions  21 ,  23 . 
         [0042]    Although not particularly shown in the figures, as an example of the extending and retracting function in the leaflet sizer in which the relative positions of the first and second commissure pointing portions  11 ,  13  are variable, the example being different from the above example, at least the edge part of any of or both of the first support portion  21  and the second support portion is extendable and retractable. In the example, the edge part has a spring structure, a bellows structure, and an elastic body. An example of the elastic body is rubber. 
         [0043]    For example, when a force is applied to the handle  33 , the first support body  21  housed in the housing portion  27  is moved in the left direction (or the right direction) in  FIG. 1 , and the relative positions of the first and second commissure pointing portions  11 ,  13  are extended. As a preferable mode of the example illustrated in  FIG. 1 , when the first support body  21  is moved in the left direction or the right direction in  FIG. 1 , the second support body  23  is moved in the opposite direction to the first support body  21 . This can be realized by a mechanism in which when the first support body  21  is moved, the second support body  23  is moved in the opposite direction. 
         [0044]    In an example illustrated in  FIG. 2 , any of or both of the first support portion  21  and the second support portion is hollow, and a coupling portion  30  is inserted into the hollow part thereof. Any of or both of the first support portion  21  and the second support portion can slide on the coupling part. In such a way, the relative positions of the first and second commissure pointing portions  11 ,  13  can be adjusted. In this example, a bar for the mark  29  for pointing the center extends from the center of the coupling portion  30 . In the example illustrated in  FIG. 2 , elements are described like a bar shape. However, in the example illustrated in  FIG. 2 , since the first and second support portions  21 ,  23  are positioned on the outer sides of the coupling portion  30 , the first and second support portions  21 ,  23  can have a smooth structure (rather bold structure). Therefore, this example can easily have a solid shape with which an actual procedure is easily performed. Specifically, the first and second support portions  21 ,  23  can be formed in a shape along the inner wall of blood vessel. 
         [0045]    A second aspect of the present invention relates to a leaflet sizer set  17  having plural leaflet sizer heads  15   a,    15   b,    15   c.  The leaflet sizer heads  15   a,    15   b,    15   c  are medical instruments respectively having first and second commissure pointing portions  11   a,    13   a  to be applied to two commissure parts in a cardiac valve for determining the size of the cardiac valve. Relative positions of the first and second commissure pointing portions are different respectively in the plural leaflet sizer heads  15   a,    15   b,    15   c.  That is, the leaflet sizer has the leaflet sizer heads in plural sizes. The plural leaflet sizers respectively have coupling holes  41   a,    41   b,    41   c  for coupling the plural leaflet sizer heads, and the plural leaflet sizer heads are integrated by a restraining body  43  passing through the coupling holes. 
         [0046]      FIG. 3  is a concept view illustrating the leaflet sizer. In this example, the plural leaflet sizer heads  15   a,    15   b,    15   c  are connected rotatably about the restraining body  43 . In an upper part of the restraining body, a handle  33  is formed. In a procedure, when the leaflet sizer head (for example,  15   b ) determined as proper by a practitioner is selected, the leaflet sizer head  15   b  is rotated and moved about the restraining body  43  by using the coupling hole  41   b.  Then, only the desired leaflet sizer head  15   b  can be taken out. The remaining leaflet sizer heads are also axially fixed to the restraining body  43  via the coupling holes  41   a,    43   c.  The remaining leaflet sizer heads  15   a,    15   c  act to press the artery and measure and test the leaflet size at the time of an actual procedure. 
         [0047]      FIG. 4  is a concept view illustrating the leaflet sizer. The leaflet sizer illustrated in  FIG. 4  has plural leaflet sizer heads  15   a,    15   b,    15   c.  The leaflet sizer heads  15   a,    15   b,    15   c  respectively have first and second commissure pointing portions  11   a,    13   a  to be applied to two commissure parts in a cardiac valve. Relative positions of the first and second commissure pointing portions are different respectively in the plural leaflet sizer heads  15   a,    15   b,    15   c.  That is, the leaflet sizer has the leaflet sizer heads in plural sizes. The plural leaflet sizers respectively have coupling holes  41   a  for coupling the plural leaflet sizer heads, and the plural leaflet sizer heads are integrated by a restraining body  43  passing through the coupling holes. In the example of  FIG. 4 , the size is written on the leaflet sizer head, so that the leaflet size is found in actual measurement. In this example, the leaflet sizer heads respectively have fixing holes  45   a,  and by letting one end of the loop shaped restraining body  43  pass through the fixing holes  45   a,  the restraining body  43  can be utilized as a handle. 
         [0048]    Next, a leaflet sizer according to another embodiment will be described with reference to  FIGS. 5, 6, 7, and 8 . The leaflet sizer illustrated in  FIGS. 5 to 8  is called as the “crossing openable and closeable type leaflet sizer” in the description of the present application. 
         [0049]    As illustrated in  FIG. 5 , the crossing openable and closeable type leaflet sizer has first and second arms  51 ,  52  crossing each other. A first commissure pointing portion  11  is provided in a leading end of the first arm  51 , and a second commissure pointing portion  13  is provided in a leading end of the first arm  62 . A coupling support point portion  53  is formed at a crossing point of the first arm  51  and the second arm  52 . This coupling support point portion  53  couples both the arms in such a manner that the first arm  51  and the second arm  52  are openable and closeable. For example, the coupling support point portion  53  may be formed by a pin, passing through the crossing point of the first arm  51  and the second arm  52  or the like. The phrase “openably and closably” means that relative positions of the leading ends of the first and second arms  51 ,  52  (that is, the first and second commissure pointing portions  11 ,  13 ) are variable. 
         [0050]    In the present embodiment, the leaflet sizer has a head  54  between the first commissure pointing portion  11  and the first commissure pointing portion  13 . As illustrated in  FIG. 5 , in a state where the first and second commissure pointing portions  11 ,  13  are closed, these pointing portions  11 ,  13  are preferably abutted with a side surface of the head  54 . This head  54  is attached to a leading end of a third arm  55 . The third arm  55  is coupled to the first arm  51  and the second arm  52  by the coupling support point portion  53 . In the present embodiment, the third arm  55  is basically immovable. That is, the first arm  51  and the second arm  52  are opened and closed so as to be moved to the left or the right side of the third arm  55  in an immovable state with the coupling support point portion  53  as a support point. Thereby, relative positions of the first arm  51  (first commissure pointing portion  11 ) and the second arm  52  (second commissure pointing portion  13 ) can be changed with the third arm  55  (head  54 ) as the center. 
         [0051]    Further, as illustrated in  FIG. 5 , the crossing openable and closeable type leaflet sizer includes a handle  33  and a guide  56 . The handle  33  serves as a gripping portion when the practitioner holds the leaflet sizer. Part of this handle  33  is inserted inside the guide  56 . A screw thread is formed in the part of the handle  33  entering the guide  56  and fitted to a screw hole formed inside the guide  56 . Therefore, by screwing the handle  33  in the fixed direction, the part of the handle  33  can be brought deeply inside the guide  56 . On the other hand, by screwing the handle  33  in the opposite direction, the part of the handle  33  can be pulled out from the inside of the guide  56 . 
         [0052]    As illustrated in  FIG. 5 , the first arm  51 , the second arm  52 , and the third arm  55  are inserted inside the guide  56  from the opposite side of the handle  33 . That is, as illustrated in the figure, the other ends of the first to third arms  51 ,  52 ,  55  opposite to the leading ends in which the pointing portions  11 ,  13  and the head  54  are provided are inserted inside the guide  56 . The other ends of the first to third arms  51 ,  52 ,  55  are coupled to the part of the handle  33 . Further, at least parts of the first and second arms  51 ,  52  inserted inside this guide  56  are made of a flexible material to be curved by applying a pressing force. The entire first and second arms  51 ,  52  can also be made of a flexible material. Therefore, when the part of the handle  33  is brought deeply inside the guide  56  by screwing the handle  33 , in accordance with the pressing force, the first and second arms  51 ,  52  are curved inside the guide  56 . 
         [0053]    Further, as illustrated in  FIG. 5 , projecting slide pins  57  are formed in the parts of the first and second arms  51 ,  52  inserted into the guide  56 . Rails  58  for guiding the slide pins  57  are formed in the guide  56 . In the example illustrated in  FIG. 5 , the rail  58  is a cut (slit) formed in the guide  56 . However, the rail  58  may be a groove formed in the guide  56 . The rail  58  is provided so as to be inclined at a predetermined angle with respect to the direction in which the handle  56  goes forward and backward. Further, although omitted in the figure, the rail  58  for guiding the slide pin  57  formed in the first arm  51  and a rail (not shown) for guiding a slide pin (not shown) formed in the second arm  52  are inclined in the opposite directions, that is, the crossing directions. Therefore, when the handle  33  is gradually brought into the guide  56 , the first arm  51  and the second arm  52  are guided by the rails  58 , so that the relative positions thereof are gradually brought apart from each other. In such a way, by biasing in the directions in which relative positions of the other ends of the first and second arms  51 ,  52  are brought apart, the relative positions of the first and second commissure pointing portions  11 ,  13  provided in the leading ends are also brought apart with the coupling support point portion  53  as a support point. Conversely, in order to bring the relative positions of the first and second commissure pointing portions  11 ,  13  close, an operation which is opposite to the above operation may be performed. Thereby, by a simple operation of screwing the handle  33 , the relative positions of the first and second commissure pointing portions  11 ,  13  can be changed. 
         [0054]      FIG. 6  illustrates a state where the leading ends of the first and second arms  51 ,  52 , that is, the first and second commissure pointing portions  11 ,  13  are closed.  FIG. 7  illustrates a state where the leading ends of the first and second arms  51 ,  52 , that is, the first and second commissure pointing portions  11 ,  13  are opened. The first and second arms  51 ,  52  are gradually spread from the closed state illustrated in  FIG. 6  to the opened state illustrated in  FIG. 7 . Therefore, by applying to commissure parts of a cardiac valve of a patient while adjusting a positional relationship of the first and second commissure pointing portions  11 ,  13 , the size of the cardiac valve can be measured. 
         [0055]      FIG. 8  schematically illustrates a state where a relation of relative positions of the first commissure pointing portion  11 , the second commissure pointing portion  13 , and the head  54  is changed in accordance with opening and closing of the first and second arms  51 ,  52 . In  FIG. 8 , a peak position of the head  54  is denoted by the reference sign P 1 , a peak position of the first commissure support portion  11  is denoted by the reference sign P 2 , and a peak position of the second commissure pointing portion  13  is denoted by the reference sign P 3 . As illustrated in  FIG. 8 , in the crossing openable and closeable type leaflet sizer, when the first and second arms  51 ,  52  are spread, the first and second commissure pointing portions  11 ,  13  are moved on the circumference of a circle centered at the coupling support point portion  33 . That is, the first commissure support portion  11  is moved from P 2  to P 2 ′, a distance from P 2  to the coupling support point portion  33  and a distance from P 2 ′ to the coupling support point portion  33  are equal. The same is applied to the second commissure support portion  13 . In the crossing openable and closeable type leaflet sizer, the peak position P 1  of the head  54  is immovable. When the size of a leaflet of a patient is measured by using the crossing openable and closeable type leaflet sizer, there is a need for paying attention to such a characteristic of the relationship of the relative positions of P 1 , P 2 , and P 3 . 
         [0056]    Next, a leaflet sizer according to still another embodiment will be described with reference to  FIGS. 9, 10, and 11 . The leaflet sizer illustrated in  FIGS. 9 to 11  is called as the “rod openable and closeable type leaflet sizer” in the description of the present application. 
         [0057]    As illustrated in  FIG. 9 , the rod openable and closeable type leaflet sizer has a base portion  61  for supporting a rod  62  so that the rod is capable of going forward and backward. This base portion  61  is fixed to a leading end of a bar shaped handle  33 . The base portion  61  has a through hole passing in the up and down direction inside thereof. The rod  62  is inserted into the through hole. The rod  62  goes forward and backward in the up and down direction by being guided by the base portion  61 . 
         [0058]    A first arm  63  and a second arm  64  are coupled outside the base portion  61 . A first commissure pointing portion  11  and a second commissure pointing portion  13  are respectively attached to leading ends of the first and second arms  63 ,  63  on the opposite side of ends coupled to the base portion  61 . Further, in the present embodiment, a third arm  65  is coupled outside the base portion  61 , and this third arm  65  is positioned between the first arm  63  and the second arm  64 . A head  66  is attached to a leading end of the third arm  65 . 
         [0059]    The rod openable and closeable type leaflet sizer also has a linking mechanism (not shown) that links the rod  62  and the first to third arms  63 ,  64 ,  65 . Such a linking mechanism is not particularly limited but can be appropriately designed by those skilled in the art. That is, as illustrated in  FIGS. 9 and 10 , the linking mechanism links forward and backward actions of the rod  62  and opening and closing actions of the first to third arms  63 ,  64 ,  65 . For example, as illustrated in  FIG. 8 , in a state where the rod  62  is pushed downward with respect to the base portion  61 , the first to third arms  63 ,  64 ,  65  are closed. On the other hand, in a state where the rod  62  is brought upward with respect to the base portion  61 , the first to third arms  63 ,  64 ,  65  are opened. By opening the first to third arms  63 ,  64 ,  65 , relative positions of the first commissure pointing portion  11  and the second commissure pointing portion  13  are brought apart. In such a way, by letting the rod  62  go forward and backward, an open and close state of the first to third arms  63 ,  64 ,  65  can be freely adjusted. Therefore, by applying to commissure parts of a cardiac valve of a patient while adjusting a positional relationship of the first and second commissure pointing portions  11 ,  13 , the size of the cardiac valve can be measured. 
         [0060]      FIG. 11  schematically illustrates a state where relative positions of the first commissure pointing portion  11 , the second commissure pointing portion  13 , and the head  66  are changed in the rod openable and closeable type leaflet sizer. In  FIG. 11 , a peak position of the head  66  is denoted by the reference sign P 1 , a peak position of the first commissure support portion  11  is denoted by the reference sign P 2 , and a peak position of the second commissure pointing portion  13  is denoted by the reference sign P 3 . As illustrated in  FIG. 11 , in the rod openable and closeable type leaflet sizer, P 1 , P 2 , P 3  are positioned on the circumference centered at a coupling support point portion  33 . When the first to third arms  63 ,  64 ,  65  are spread, the positions P 1 , P 2 , P 3  are changed to P 1 ′, P 2 ′, P 3 ′ in such a manner that the radius of a circle centered at the base portion  11  is extended. In the rod openable and closeable type leaflet sizer, extension width of P 1 , P 2 , P 3  are all uniform. That is, a distance from P 1  to P 1 ′, a distance from P 2  to P 2 ′, and a distance from P 3  to P 3 ′ are always equal. In such a way, by using the rod openable and closeable type leaflet sizer, the practitioner can measure the size of the leaflet assuming similar fan shapes. 
         [0061]    Next, an example of aortic valve reconstruction of forming an aortic valve by using a leaflet material formed by a patient&#39;s own cardiac membrane will be described. In this case, after the sternum is exposed, median sternotomy is performed. After that, an incision is made in the cardiac membrane. In a state where the heart is exposed, extracorporeal circulation is performed with an artificial heart and an artificial lung. After a cardiac arrest, the aortic valve is exposed. Meanwhile, the cardiac membrane acquired in advance is extended and fixed by a thread and in that state, soaked into a tissue fixative solution (for example, a solution containing glutaraldehyde). 
         [0062]    Next, part of three leaflets of the aortic valve to be removed is cut out. The leaflet sizer is applied to the cut part, and the size of the cut leaflet is measured (based on a distance between commissure parts). The cardiac membrane is taken out from the tissue fixative solution. Based on a template corresponding to the leaflet sizer (of the size corresponding to the commissure parts of the cut leaflet), a line is drawn on the cardiac membrane. The cardiac membrane is cut and a leaflet material is obtained. The leaflet material is soaked into for example a normal saline solution. 
         [0063]    Next, a leaflet is formed by using the obtained leaflet material. Basic tasks of specific procedures are the same as JP 5106019 B2. That is, with an indicator formed at a position corresponding to a center point of the leaflet as a mark, a suture is placed on a position pointed by the indicator and the center point is stitched up. With this center point as a basis, stitching is made toward the commissure parts. In a lower end region of a leaflet base portion  25 , intervals of a needle are preferably short. 
         [0064]    The embodiments of the present invention can be utilized in the field of medical instruments. 
       REFERENCE NUMERALS LIST 
       [0000]    
       
           11 : First commissure pointing portion 
           13 : Second commissure pointing portion 
           15 : Leaflet sizer 
           21 : First pointing portion 
           25 : Indicator display portion 
           27 : Housing portion 
           31 : Leaflet sizer main body 
           33 : Handle 
           51 : First arm 
           52 : Second arm 
           53 : Coupling support point portion 
           61 : Base portion 
           62 : Rod portion 
           63 : First arm 
           64 : Second arm