Patent Application
20110071622
This application is a continuation of German Patent Application No. DE 10 2009 042 465.2 filed Sep. 23, 2009, which is hereby incorporated by reference in it's entirety.
The invention relates to an instrument for the surgical treatment of aortic valve defects, in particular in young patients such as children.
The aortic valve (valva aortae) is arranged as valve system in the aortic opening of the left ventricle which opens during the systole under ventricular pressure of the blood and closes during the diastole under arterial pressure. The aortic valve has three valve leaflets which are attached via commissures at the annulus fibrosus. The valve leaflets have semilunar valve cusps (valvulae semilunares) which form a valve cusp sinus (sinus valsalvae). The valve cusps abut against each other with their free leaflet edges in the closed position in a sealing manner to prevent a back current of the blood from the aorta into the left ventricle. In the open position, the free edges of the elastic flexible cusps are moved away from each another.
Aortic valve defects can result in an aortic valve insufficiency or aortic valve stenosis. In case of the aortic valve insufficiency, the artic valve does not close completely whereas in case of the aortic valve stenosis, the opening of the aortic valve is narrowed. Different surgical methods for the treatment of aortic valve defects are known. The defect aortic valve can be completely or partially replaced by a mechanical or biological valve prosthesis. In addition, surgical methods are known in which the patient's own aortic valve remains intact to the greatest possible extent and the function is restored by surgical reconstruction. Typical here are in particular plicatures or tightening the cusps or reconstructions of the connection of the aortic valve. Valve prostheses involve the risk of rejections and thromboses. Therefore, a reconstruction of the aortic valve is to be preferred if this is possible.
Aortic valve defects in children, which are usually congenital, involve primarily aortic valve insufficiencies wherein the valve leaflets are malformed or not completely developed. In such patients, the reconstruction of the aortic valve is of particular importance to allow the aortic valve to grow along and to avoid a potentially lifelong medication.
The invention is based on the object to facilitate and improve the surgical treatment of aortic valve defects, in particular in young patients such as children.
This object is solved according to an instrument for the surgical treatment of aortic valve defects, in particular in young patients such as children, having the structures and features recited herein. Advantageous embodiments of the invention are specified in the sub-claims.
According to the invention, the surgeon is provided with an instrument which makes the surgical intervention easier and more reliable and by means of which a defect aortic valve can be converted into a functionally sufficient aortic valve. In case of acquired aortic valve insufficiencies, the natural aortic valve with its functional capability can be reconstructed. The instrument is in particular suitable for the correction of congenital aortic valve insufficiencies, wherein formally and functionally sufficient valve leaflets are made from the existing defect aortic valve leaflets.
The instrument according to the invention consists of a shaft having a proximal handle and a leaflet body arranged at the distal shaft end. The leaflet body has substantially the shape of the inner sinus of the valve leaflet. The instrument can be used in two ways. First, the instrument can be used as gage to palpate the valve leaflet. For this, a set of instruments each with differently sized leaflet bodies is used. By inserting the different leaflet bodies into a valve leaflet having a damage as small as possible, the surgeon can determine the optimal size of the valve leaflets. Subsequently, the instrument with the optimal leaflet body determined through the gaging is used as shaping body, around which the surgeon constructs a formally and functionally sufficient valve leaflet using the body's own valve tissue or pericardial tissue. The leaflet body of the instrument is used here in a similar manner as the last for manufacturing shoes. By shaping and suturing the tissue around the shaping leaflet body it is made easier for the surgeon to operatively construct a valve leaflet which is almost identical to the geometrical shape of the natural valve leaflet.
To optimize the handling of the instrument, the shaft of the instrument is flexible and in particular plastically deformable. The surgeon can bend the shaft for an optimal handling so as to insert the leaflet body in the anatomically most advantageous way and under the most advantageous visibility and surgery conditions into the respective valve leaflet.
In an advantageous embodiment, the shaft is made of a memory metal, e.g. a martensitic nickel-titanium alloy which is plastically deformable at room temperature and which adopts its original shape again upon exceeding the higher upper transition temperature. The instrument is available with a straight shaft and can be bent by the surgeon into the suitable shape for the subsequent use. The shaft maintains this shape until the transition temperature is exceeded during the instrument preparation in the washing machine and in the autoclave and the shaft of the instrument adopts its straight original shape again.
Hereinafter, the invention is explained in more detail by means of an exemplary embodiment illustrated in the drawing. In the figures:
a, b and c show the leaflet body of the instrument in different views.
The anatomical structure and shape of an aortic valve (valva aortae) is schematically illustrated in the
The aortic valve 10 has three valve leaflets 12. They fill the cross-section of the aortic valve 10 substantially in the form of three sectors of a circle as it is shown in
The instrument illustrated in an exemplary embodiment in the
The shaft 24 is preferably made of a memory metal, in particular a martensitic nickel-titanium alloy. In its original shape, the shaft 24 extends in a straight line. Due to the memory properties of the material, the shaft 24 is plastically deformable at room temperature and can be bent in any desired curvature shape. The shaft 24 maintains said curvature shape at room temperature. If the shaft 24 is heated above its upper transition temperature, which lies above the room temperature, e.g. during the instrument preparation in a washing machine or in the autoclave, it adopts its straight original shape again.
The leaflet body 28 has substantially the shape of the sinus 14 of the valve leaflets 12. Accordingly, the leaflet body 28 has two flat surfaces 30 which run substantially at an angle of 120° to each other and a circular-cylindrically curved outer surface 32. The cross-section of the leaflet body 28 thus corresponds substantially to the cross-section of the sinus 14 of the valve leaflet 12 in the closed position of the valves as it is shown in
The instrument 28 is produced with differently sized leaflet bodies 28 which correspond to the different sizes of the aortic valve 10, in particular in young patients such as children.
For a surgical operation of an aortic valve defect, in particular in young patients such as children, the surgeon selects first the aortic valve's 10 valve leaflet 12 with the best shape and gages the sinus 14 of the same. For this, he uses successively a plurality of instruments with differently sized leaflet bodies 28 to determine the size of the leaflet body 28 which corresponds best to the valve leaflet 12.
The defect or malformed valve leaflets 12 are then surgically constructed by using the selected leaflet body 28 as shaping body and the malformed or missing valve cusp 20 is formed around said leaflet body 28. For this, the surgeon uses the defect valve tissue or, if this is not sufficient, pericardial tissue can also be used. The tissue is formed around the leaflet body 28 and sutured. If necessary, the other valve leaflets 12 of the aortic valve 10 are constructed in the same manner.
By means of the instrument according to the invention, the surgeon can construct, in a relatively simple and reliable manner, geometrically identical valve leaflets 12 which come as close as possible to the natural shape of the valve leaflets 12. Since the valve leaflets are made of the patient's own body tissue, there are no problems with rejections and no risk of thrombosis.
10 Aortic valve
12 Valve leaflets
14 Sinus valsalvae
16 Sinotubular junction
18 Annulus fibrosus
20 Valve cusp
22 Free edge
24 Shaft
26 Handle
28 Leaflet body
30 Flat surfaces
32 Outer surface
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2009 042 465.2 | Sep 2009 | DE | national |
