Instrument of patterning cusp for cardiac valve reconstruction and component thereof

Abstract

In a case of repairing an aortic valve by forming a valve cusp with a biomembrane, the shape and the size of a valve cusp can be determined easily. An instrument including a valve cusp sizer for measuring the size of the valve cusp and a template for scribing lines for the shape of a valve cusp conforming to the measured size of the valve cusp, in which the valve cusp sizer has a plurality of differently-sized sizer blocks attached to each of the top ends of grip members respectively and each sizer block has an arcuate surface formed by cutting each of differently-sized circular cylinders at an angle conforming to the central angle for the commissure portions and, the template is formed with a scribing portion including a substantially semi-circular valve cusp base forming portion.

Claims

1. A method of treatment of abnormal valve cusp syndrome, the method comprising: excising a plurality of abnormal valve cusps selected from the group of left coronary cusp, right coronary cusp and noncoronary cusp; inserting a cusp sizer at a portion where the plurality of abnormal valve cusps are excised, wherein the cusp sizer comprises a sizer block with an arcuate surface with an angle conforming to the central angle for commissure portions of an aortic valve, the arcuate surface comprising two probe portions disposed on both ends thereof; an upper surface of the sizer block being curved in a concave shape and comprising an index which is a center marker for defining a central point from which stitching is started; measuring the size of the excised valve cusps by: making the sizer block abut the valve annulus of an aorta from which the valve cusps are excised, the central point for the base of each valve cusp between the commissure portions being visible; confirming the two probe portions of the sizer block fit to both of the commissure portions of one of the excised abnormal valve cusps, thereby reading nominal diameter of the cusp sizer; obtaining a new valve cusp formed of a pericardium by: scribing lines for a cusp shape by drawing along an inner peripheral surface of a scribing portion of a template which relates to the nominal diameter to the pericardium; and cutting the pericardium in accordance with the lined cusp shape; dipping the new valve cusp formed of a pericardium in saline; abutting the cusp sizer having the nominal diameter in a manner that the two commissure portions of the excised valve cusp conforms to the two probe portions of the sizer block; putting a thread to a valve annulus at a position indicated by the index; stitching the central point of the base of the valve cusp; and stitching toward the commissure points from the central point, thereby reconstructing the aortic valve.

2. The method in accordance with claim 1, wherein dipping the new valve cusp comprises dipping the new valve cusp in one of a left coronary cusp dipping portion, right coronary cusp dipping portion and a noncoronary cusp dipping portion of a vessel, the left coronary cusp dipping portion comprising an identification tag of the left coronary cusp dipping portion; the right coronary cusp dipping portion comprising an identification tag of the right coronary cusp dipping portion; and the noncoronary cusp dipping portion comprising an identification tag of the noncoronary cusp dipping portion.

3. The method in accordance with claim 1, wherein obtaining the new valve cusp comprises obtaining the new valve cusp by: lining for a cusp shape by drawing along an inner peripheral surface of a scribing portion of a template which relates to the nominal diameter to the pericardium, the inner peripheral surface of the scribing portion comprising: an inner peripheral surface of a valve cusp base forming portion of the template which has a diameter as a sum of a diameter defined as the nominal diameter and an allowance for stitching margins; and an inner peripheral surface of a coaptation zone forming portion in which both end edges thereof are extended in a manner that the portion is gradually widened from both ends of the valve cusp base forming portion angled shape portion of the template to a free margin portion thereof, and a center of the free margin portion being protruded at the top end thereof and having an angled shape.

4. The method in accordance with claim 1, wherein the plurality of abnormal valve cusps comprises three or all abnormal valve cusps selected from the group of left coronary cusp, right coronary cusp and noncoronary cusp.

Description

BRIEF EXPLANATION OF THE DRAWINGS

(1) FIG. 1 is an explanatory view showing an example of a valve cusp forming instrument according to the invention.

(2) FIG. 2 is an explanatory view showing a valve cusp sizer.

(3) FIG. 3 is an explanatory view showing a template.

(4) FIG. 4 is an explanatory view showing another embodiment of a template.

(5) FIG. 5(a) is an explanatory view showing an aortic valve before excising a valve cusp.

(6) FIG. 5(b) is an explanatory view showing an aortic valve from which a valve cusp has been excised.

(7) FIG. 5(c) is an explanatory view showing the state of measuring the size of a valve cusp.

(8) FIG. 6 is an explanatory view showing the template in the state of use.

(9) FIG. 7 is an explanatory view showing a petri dish type vessel for preparing each cusp individually.

(10) FIG. 8 is a schematic view of a heart.

(11) FIG. 9(a) is an explanatory view showing an aortic valve in a closed state.

(12) FIG. 9(b) is an explanatory view showing an aortic valve in an open state.

(13) FIG. 10(a) is a view showing an aortic valve in which valve cusps are calcified.

(14) FIG. 10(b) is a view showing an aorta valve from which all valve cusps are excised.

(15) FIG. 10(c) is a view showing the state of measuring the inner diameter of an aortic valve by using an existent sizer.

(16) FIG. 10(d) is a view showing an aorta replaced with a prosthetic valve by existent aortic valve replacement.

(17) FIG. 11 is an explanatory view showing a model of a valve cusp.

PREFERRED EMBODIMENTS OF THE INVENTION

(18) The present invention intends to easily determine the shape and the size of a valve cusp in a case of reconstructing, a tricuspid cardiac valve such as an aortic valve by replacing only the valve cusp which is no more usable using, an autologuous biomembrane, etc.

(19) For this purpose, an instrument of patterning a valve cusp used for aortic valve reconstruction by stitching a valve cusp patterned from an artificial membrane or a biomembrane to a portion of a tricuspid cardiac valve such as an aortic valve from which the abnormal cusp has been excised includes;

(20) a valve cusp sizer for measuring the size of a valve cusp conforming to the size of a cardiac valve, and

(21) a template for scribing lines of the shape of the valve cusp on the artificial membrane or the biomembrane conforming to the measured size of the valve cusp.

(22) The valve cusp sizer has a plurality of differently-sized sizer blocks for measuring the length of a valve annulus extending from one commissure portion of a cusp to a valve annulus to the other commissure portion of the cusp to the valve annulus of an excised valve cusp, where each of the seizer blocks is attached to each of the top ends of grip members respectively and each of the sizer blocks has with an arcuate surface formed by cutting each of differently-sized circular cylinders at an angle conforming to the central angle for the commissure portions.

(23) The template is formed with a scribing portion including a substantially semi-circular valve cusp base forming portion having a diameter as a sum of a nominal diameter defined as a diameter of a circular cylinder constituting the arcuate surface of a sizer block whose arcuate surface conform at both ends thereof to both of the commissure portions of the excised valve cusp when the cusp sizer is inserted to a valve annulus from which the valve cusp has been excised and an allowance for stitching margins, and a coaptation zone forming portion in contiguous with the valve cusp base forming portion.

First Embodiment

(24) FIG. 1 shows an instrument 1 of this embodiment which includes a valve cusp sizer 2 for measuring the size of a valve cusp conforming to the size of a cardiac valve, a template 3 for scribing lines of a shape of the valve cusp on an artificial membrane or a biomembrane conforming to the measured size of the valve cusp, and a base plate 4 for maintaining the artificial membrane or the biomembrane in a planar state upon scribing the lines for the shape of the cusp by using the template 3.

(25) The valve cusp sizer 2, the template 3, and the base plate 4 are contained in a stainless steel case 5, and they can be sterilized in a state as they are contained therein by an sterilizing autoclave.

(26) In the case 5, a main body 51 for containing the valve cusp sizer 2, and a cover 52 for containing the template 3 and the base plate 4 are opened and closed by a hinge 53, and a partition plate 54 is disposed therebetween.

(27) The cusp sizer 2 has a plurality of differently-sized sizer blocks G.sub.1 to G.sub.8 for measuring the length of the valve annulus from one commissure portion of a valve cusp to a valve annulus to another commissure portion of the valve cusp to the valve annulus of an excised valve cusp, and each of the sizer blocks is attached to each of the top ends of grip members 21, 21.

(28) Then, as shown in FIG. 2, each of the sizer blocks G.sub.1 to G.sub.8 has, as a basic shape, a partial circular cylinder 23 formed by cutting different-sized circular cylinder 22 at an angle conforming to the central angle for the commissure portions of the aortic valve (120° in this embodiment, while assuming that the central angles for three commissure portions K are equal).

(29) The outer peripheral surface is formed as an arcuate surface 24 to be abutted against the valve annuls of an aorta from which an abnormal valve cusp has been excised, and contact probe portions 25 of a predetermined length for positioning and abutting both ends of the arcuate surface 24 against the commissure portions K, K are formed in parallel with the central axis of the arcuate surface 24.

(30) The diameter of the circular cylinder 22 (arcuate surface 24) is used as the nominal diameter (D.sub.1 to D.sub.8) for defining the size of the valve cusp. In this embodiment, sizer blocks G.sub.1 to G.sub.8 having eight types of nominal diameters D.sub.1 to D.sub.8 from 17 to 31 mm on every 2 mm step are used while considering the personal differences for the diameter of adult aorta.

(31) Then, numerical values for the nominal diameters D.sub.1 to D.sub.8 are indented to the grip members 21 such that the size of the sizer block D.sub.1 to D.sub.8 attached to the top ends thereof can be read.

(32) Further, the central point P.sub.C for the base B of the valve cusp is at a position lower than the bottom end C.sub.L of a coaptation zone (refer to FIG. 11). Therefore, the upper surface 26 for each of the sizer blocks G.sub.1 to G.sub.8 is formed being curved in a concave shape such that the central point P.sub.C for the base B of the valve cusp between the commissures portions K, K where the valve cusp is to be stitched can be seen when each of the contact probe portions 25 is abutted against each of the commissure portions K, K from which the valve cusp has been excised.

(33) Further, an index 27 as a center marker for defining the central point P.sub.C is formed at a position of the upper surface thereof corresponding to the central point P.sub.C in a case of starting stitching from the central point P.sub.C.

(34) Then, the grip member 21 is attached to the center of the partial circular cylinder 23 that forms each of the sizer blocks G.sub.1 to G.sub.8 such that it does not hinder the observation of the valve annulus in a state of abutting the arcuate surface 24 of each of the sizer blocks G.sub.1 to G.sub.4 to the valve annulus, and the grip member 21 is inclined by a predetermined angle θ (θ=30°) in this embodiment) relative to the central axis X to the side opposite to the arcuate surface.

(35) FIG. 3 shows the template 3 which is put over the artificial membrane or the biomembrane for scribing the lines of the shape of the valve cusp by using a sterilized surgery skin marker, etc. and in which a plurality of scribing portions 31 having differently-sized shapes of the valve cusp are perforated.

(36) The scribing portion 31 is formed as a semi-circular-rectangular part comprising a substantially semi-circular base forming portion 32 and a substantially rectangular coaptation forming portion 33 in contiguous therewith.

(37) When assuming that a valve cusp sizer 2 is inserted to a valve annulus from which a valve cusp has been excised and that contact probes 25 formed on both ends of the arcuate surface of a sizer block Gn (G.sub.1 to G.sub.8) conform to both of the commissure portions of the excised valve cusp, the valve cusp base forming portion 32 has a diameter as a sum of the diameter defined as a nominal diameter Dn of the circular cylinder and an allowance for stitching margins 2W on both right and left sides (Dn+2w). The stitching margin is designed as: w=3 mm in this embodiment.

(38) Further, the coaptation zone forming portion 33 is formed as a rectangular shape having a width equal with the diameter of the cusp base forming portion 32 from both ends of the cusp base forming portion 32 to the free margin portion 34 at the top end, and having a length h of 12 mm which is necessary and sufficient as the height for the coaptation zone.

(39) Then, nominal diameters D.sub.1 to D.sub.8 are described as guide numbers for respective scribing portions 31. Thus, the scribing portion 31 conforming to the measured nominal diameter Dn of the aorta measured by the cusp sizer 2 can be selected easily.

(40) FIG. 4 shows another improved template 6, in which the shape of the scribing portions 61 is improved for further decreasing the back flow blood.

(41) This embodiment is identical with the first embodiment in that a cusp base forming portion 62 is formed of a semi-circle having a diameter as a sum of the nominal diameter Dn and an allowance for the stitching margins 2w on both right and left sides (Dn+2w).

(42) A coaptation zone forming portion 63 is formed as a pentagonal shape in which both end edges thereof are extended for a length h conforming to the height of the coaptation till it reaches the free margin 64 at the top end while being gradually widened from both ends of the semi-circular cusp base forming portion 62, and the center of the free margin portion 64 at the top end thereof is protruded into an angled shape.

(43) In this embodiment, the maximum width α of the coaptation zone forming portion 62 is designed as: α=1 mm and the protrusion length β at the center of the free margin portion 64 is designed as: β=2 to 3 mm.

(44) In this embodiment, an allowance is provided for the length of the free margin portion 64 by gradually increasing the width thereof while maintaining the substantially rectangular shape as the coaptation zone forming portion 63, and air tightness is improved when the valve cusps are closed to reliably prevent backflow of the blood by increasing the height for the central portion where three valve cusps are in contact with each other.

(45) The base plate 4 is formed, for example, of a stainless steel plate in which perforations 41 are formed at the periphery thereof for putting and stretching threads 43 that are passed through the biomembrane or the artificial membrane (refer to FIG. 1, FIG. 6).

(46) The constitution of the embodiment of the present invention is as has been described above and the operation thereof is to be described to an example for the treatment of aortic valve stenosis with reference to FIG. 5 and FIG. 6.

(47) Aortic valve reconstruction is applied, for example, by leaving two valve cusps 12, 12 that can function normally by removing a calcium component by a supersonic surgical aspirator as they are and replacing only one valve cusp 12a that cannot be repaired by decalcification with a prosthetic valve cusp formed of an autologuous pericardium among three valve cusps 12 of an aortic valve 11 suffering from aortic valve stenosis caused by deposition and calcification of calcium.

(48) In this case, skins, subcutis, and fascia are at first incised to exteriorize sternum, which is subjected to medium sternotomy and then the pericardium is incised. Then, extracorporeal circulation is started by a pump oxygenator in a state of exposing the heart and, after stopping cardiac activity, the aortic valve 11 is exposed on the side of the aorta.

(49) Then, the pericardium is incised into an appropriate size and the pericardium 42 is extended over the base plate 4 and dipped in a histological fixture such as glutaraldehyde in a fixed state by putting around threads 43.

(50) Then, as shown in FIG. 5(a) to (b), among three valve cusps 12 of the aortic valve 11, one valve cusp 12a is excised by applying a surgical knife along the fixing edge 13 thereof, a cusp sizer 2 is inserted to the portion as shown in FIG. 5(c) to measure the size of the excised valve cusp 12a.

(51) Specifically, differently-sized sizer blocks G.sub.1 to G.sub.8 of the cusp sizer 2 are inserted successively and abutted to the valve annulus of the aorta 10 from which the valve cusp 12a has been excised, and a sizer block Gn in which the contact probe portions 25 disposed on both ends of the arcuate surface 24 thereof conform to both of the commissure portions K, K of the excised valve cusp 12a is confirmed and the nominal diameter Dn for the cusp sizer 2 is read.

(52) When the nominal diameter Dn that determines the cusp size is decided, the pericardium 42 dipped in glutaraldehyde is taken out together with the base plate 4, over which the template 3(6) is placed, and lines for the cusp shape is drawn along the inner peripheral surface of the scribing portion 31 (61) conforming to the nominal diameter Dn on the autologuous pericardium 42 by a skin marker 44. Then, it is detached from the base plate 4 and cut into the scribed shape by a shear sizer and dipped in physiological saline for preventing drying.

(53) In a case of forming, for example, only one valve cusp, the valve cusp-formed of the pericardium 42 may be dipped in a vessel such as a tray or a Petri dish containing physiological saline. However, the tricuspid valve of the aortic valve includes three members of right coronary valve cusp, left coronary valve cusp, and non-coronary valve cusp. In a case of forming two or more of them and if the size of respective cusps are different subtly, when they are happened to be stitched erroneously, this brings about a trouble in the aortic valve reconstruction.

(54) In order to prevent this, as shown, for example, in FIG. 7, a petri dish type vessel 7 for preparing each cusp individually is used. The vessel is partitioned into three parts of a right coronary cusp dipping portion 8R, a left coronary cusp dipping portion 8L, and a non-coronary cusp dipping portion 8N by partition walls 7a, and identification tags 9R, 9L, 9N are attached for identifying respective dipping portions 8R, 8L, 8N. By filling the respective dipping portions 8R, 8L, 8N with physiological saline and dipping valve cusps formed of the pericardium 42 into respective dipping portions 8R, 8L, 8N, a risk of erroneously stitching them during surgery can be prevented.

(55) Then, when the valve cusp can be formed from the autologuous pericardium 42, the cusp sizer 2 having the nominal diameter Dn is again abutted so as to conform the contact probe portions 25 thereof to both commissure portions K, K of the excised valve cusp 12a, a thread is put to a valve annulus at a position indicated by an index 27 formed to a position corresponding to the central point P.sub.C of the base B of the valve cusp with reference to the index 27, the central point P.sub.C of the base B of the valve cusp is stitched and then they are stitched successively toward respective commissure portions K, K with the point Pc as a reference.

(56) Thus, the aortic valve can be reconstructed by stitching a valve cusp formed of the autologuous pericardium to a portion where the valve cusp 12a has been excised.

(57) Since the valve cusp formed as described above is made of the autologuous pericardium, it does not cause rejection. Further, since the valve annulus of the aortic valve can be utilized as it is, no additional valve annulus is formed and projected into the aorta and, accordingly, the pressure loss during opening of the valve is extremely small.

(58) While the description has been made to a case of forming the valve cusp with the pericardium, the present invention can be applied also to a case of forming the valve cusp with a heterogenic biomembranes of animals such as cattle, horses and swinery, as well as with artificial membranes.

INDUSTRIAL APPLICABILITY

(59) As has been described above, the present invention is applicable use of forming a valve cusp of optimal size and shape upon treatment of abnormal valve cusp syndrome by cardiac valve reconstruction of stitching a valve cusp formed of an artificial membrane or a biomembrane to a portion of a tricuspid cardiac valve such as an aortic valve from which an abnormal valve cusp has been excised.

DESCRIPTION OF THE REFERENCES

(60) 1 valve cusp forming instrument 2 valve cusp sizer. 3 template. G.sub.1 to G.sub.8 sizer block 21 grip member 22 circular cylinder 24 arcuate surface 25 contact probe portion 31 scribing portion 32 valve cusp base forming portion 33 coaptation zone forming portion D.sub.1 to D.sub.8 nominal diameter