The present invention relates to a surgical instrument for suturing a surgical part such as an incised part or a wound in biological tissue and stopping bleeding from the surgical part, and more particularly to a surgical needle made of a shape memory alloy which has been variously shape memory-processed.
Development of various medical instruments is proceeding. For example, a stent constructed of a stainless steel mesh in order to prevent stricture of a blood vessel has been devised, and a stent constructed of a shape memory alloy also has recently been devised. (Refer to Patent Literatures 1 and 2.)
Development of other medical instruments also has advanced, and, for example, various instruments and suture needles have been devised in order to suture a wound in a patient. For example, Patent Literature 3 discloses a suture needle in which a surface of a needle tip has been subjected to blasting in order to reduce piercing resistance when the needle pierces through biological tissue, and Patent Literature 4 discloses a suture needle in which a spiral concave groove is formed in the needle from its distal end side to proximal end side so as to reduce the piercing resistance and thereby provide good suture which is not prone to impose a load on the biological tissue. Also, Patent Literature 5 discloses a surgical needle having a shape memory effect, and Patent Literature 6 discloses a suture thread having the shape memory effect.
However, a conventional surgical needle has required skill and time since the surgical needle, whenever used, has been used in combination with a suture thread to suture an incised part and stop bleeding from the incised part. Further, there has been a demand for quick, safe and reliable immobilization (or cauterization) of biological soft tissue in surgery under a scope or robotic surgery which limits the use of hands.
Patent Literature 1: Japanese Patent Application Publication No. Hei 10-337333
Patent Literature 2: Japanese Patent Application Publication No. 2011-010866
Patent Literature 3: Japanese Patent Application Publication No. 2005-334193
Patent Literature 4: Japanese Patent Application Publication No. 2007-229026
Patent Literature 5: Japanese Patent No. 3700089
Patent Literature 6: Japanese Patent No. 3193971
The present invention has been made in view of the above circumstances. An object of the present invention is to provide a surgical needle capable of shortening operation time by ligating an incised part without the use of a threaded surgical needle, and also capable of cauterizing the incised part.
As a result of devoting efforts to studies in view of the above object, the inventors have brought the present invention to completion by finding out that, instead of the conventional concept that a thread is used to suture soft tissue, transformation of a shape memory alloy is utilized to suture an incised part or a wound, and also, cauterization of the incised part or the wound is done to immobilize tissue near and around the incised part or the wound.
Specifically, the present invention provides a surgical needle including a shape memory alloy which has been shape memory-processed to return, at a temperature equal to or higher than its transformation point, to its original shape selected from a group consisting of a ring shape, a spiral shape, a coil shape and a clinch shape.
The shape memory alloy is characterized by being shaped in an arcuate shape, a spiral shape or a substantially U-shape. Also, in a preferred embodiment of the present invention, at the temperature equal to or higher than the transformation point, the shape memory alloy returns from the arcuate shape to the ring shape or the spiral shape, or returns from the spiral shape to the coil shape, or is transformed from the substantially U-shape into the clinch shape.
Return of the shape memory alloy to the original shape can be accomplished by heating the shape memory alloy through energization. In the surgical needle of the present invention, suture and/or hemostasis of an incised part can be done by ligation of the incised part or cauterization around the incised part.
Further, desirably, the surgical needle of the present invention is formed in such a manner that its end portion is sharp-edged.
The transformation point of the shape memory alloy is selectable from substantially a range of 30° C. to 110° C., depending on a mixing ratio between nickel and metal such as titanium which make up the shape memory alloy. Preferably, the transformation point of the shape memory alloy is set equal to or higher than 40° C., taking suture of biological tissue into account.
According to the surgical needle of the present invention, the operation time required to ligate an incised part or a wound in various organs (such as the digestive tract) in the body or the skin or the like can be shortened, and besides, the incised part or the wound can be cauterized, which in turn enables controlling the speed and strength of ligation and a cauterization range. Specifically, the speed of the ligation can be controlled by changing an applied voltage. Also, the strength of the ligation and the cauterization range can be controlled by changing the voltage and energization time.
Use of the surgical needle of the present invention makes it unnecessary to employ a threaded suture needle, shortens the operation time required to ligate an incised part or a wound in an organ such as the digestive tract in the body or the skin or the like, and allows cauterization of the wound.
Also, the surgical needle of the present invention can be used in surgery under a scope such as endoscopic surgery or robotic surgery, thus allowing simple and easy operation of a tool or an instrument (such as a forceps) taken out of a forceps hole in a leading end portion of an endoscope.
The present invention relates to a surgical needle made of a shape memory alloy which has been shape memory-processed to return to a predetermined shape at a temperature equal to or higher than its transformation point. The surgical needle of the present invention is made of the shape memory alloy, and, after the surgical needle has bitten into soft tissue, the shape memory alloy is energized and thereby heated to return to its original shape, and thereby, a physical ligation effect and a cauterization effect for surrounding soft tissue can be achieved to thus enable closing an incised part and stopping bleeding from the incised part.
The surgical needle which has been shape memory-processed by using the shape memory alloy can be flexibly transformed at a temperature lower than the transformation point (martensite) and returns to the original shape at or above the transformation point (austenite). Thus, for example, if a shape memory alloy having a transformation point of 40° C. is shape memory-processed, the shape memory alloy can be flexibly transformed below the transformation point, such as at room temperature, and returns to its original shape when heated to the transformation point or higher.
The surgical needle of the present invention, as compared to a stent for blood vessel, is different from the stent in intended use, approach and mechanism of operation in the following respects. Specifically, the stent for blood vessel assumes a mesh structure, and, after staying in a blood vessel, the stent undergoes a temperature change such as warm water injection thereby to return to its original shape and consequently expand an inner diameter of the blood vessel.
Meanwhile, the surgical needle of the present invention is characterized in that (i) its use is intended for ligation and hemostasis, (ii) the approach involves inserting the needle into a soft part such as biological tissue, and thereafter heating a suture instrument by energizing the suture instrument through a forceps, tweezers or the like, and (iii) the mechanism of operation involves using a shape restoring force of the shape memory alloy to ligate an incised part or a wound, and utilizing the effect of cauterizing the surroundings of the incised part or the wound.
Further, the surgical needle of the present invention is configured so that the needle in itself bites into soft tissue and returns to the original shape to suture an incised part, and the surgical needle of the present invention is different from the conventional surgical needle and suture thread (refer to Patent Literatures 5 and 6, for example) in that the surgical needle of the present invention does not use a suture thread in itself.
The shape of the surgical needle of the present invention is not particularly limited, provided only that it permits suture of biological tissue, and the shape memory alloy which has been shape memory-processed is shaped in such a shape as to facilitate suture of an incised part and a cauterization operation for surrounding tissue. For example, preferably, the shape after returning to the original shape is a ring shape, a spiral shape, a coil shape or a clinch shape.
Also, the shapes before returning to the original shape include a sharply or gently curved sharp (or an arcuate shape) given to a surgical sharp or round needle or the like, the shape (or a substantially C-shape) of an arcuate needle having sharp-edged ends, a spiral shape, and a substantially U-shape, in order that the needle can easily bite into soft tissue in the incised part. (See
Return of the shape memory-processed surgical needle to the original shape can be accomplished by heating the shape memory alloy to its transformation point or higher. There are various methods for heating the shape memory alloy to the transformation point or higher; for example, the surgical needle may be energized through tweezers or a forceps capable of power supply thereby to produce Joule heat and utilize the Joule heat to heat the shape memory alloy to the transformation point or higher. An electrode may be connected beforehand to the tweezers or the forceps so as to enable supplying a current. Also, after the insertion of the surgical needle of the present invention into biological tissue around an incised part or a wound, an electrode terminal capable of current supply may be connected to the surgical needle to apply the current to the surgical needle. Incidentally, heat may also be supplied to the surgical needle to increase the temperature of the surgical needle to the transformation point or higher and allow the surgical needle to return to the original shape.
Description will be given below with regard to more specific embodiments of the present invention.
The shape memory alloy has the property of returning to its original shape when the shape memory alloy reaches a temperature equal to or higher than its transformation point, and the surgical needle of the present invention can utilize the property to ligate an incised part or a wound. Further, the shape memory alloy is of relatively high electrical resistance and thus produces Joule heat during energization. The shape of the shape memory alloy can return from martensite to austenite by the heat produced by the energization.
The shape memory alloy is an alloy of nickel and metal selected from titanium, aluminum, cobalt, iron, manganese and the like, and varies in molecular structure from one to another of two phases, namely, the martensite and the austenite. For example, a typical shape memory alloy assumes the martensite below 25° C. and assumes the austenite at or above 32° C.; however, this can be adjusted by changing a mixing ratio between nickel and titanium or the like and may be changed as appropriate for adaptation to the required transformation point. To shape memory-process the shape memory alloy, a wire of the shape memory alloy is wound around a jig having a predetermined shape or the alloy is charged into a mold, and the whole jig or mold is put in an oven and is subjected to heat treatment (at about 400° C. to 500° C. for about an hour). After the heat treatment, the shape memory alloy is removed from the jig or the mold, and the shape memory alloy can be shaped in the desired one of the shapes illustrated in
Preferably, the surgical needle of the present invention has the transformation point in a range of 40° C. to 100° C. When the surgical needle has such a transformation point, the surgical needle is transformed from the martensite into the austenite to return to the original shape, for example by heating the surgical needle to at least 40° C. or higher. Also, the proportion of nickel in the shape memory alloy may be reduced to increase the transformation point to about 50° C., thereby preventing the surgical needle from returning to the original shape after merely suturing biological tissue in a patient, and also achieving a structure such that the surgical needle does not return to the original shape unless the surgical needle is externally heated to 50° C. or higher. The surgical needle which achieves greater ease of use can be provided by setting the transformation point of the shape memory alloy in this manner. The transformed surgical needle stays in an incised part or a wound to thus close the incised part or the wound and hence enable preventing tissue therearound from becoming damaged.
Heating temperature of the shape memory alloy can be controlled by changing electric power applied to a resistor, since energization is based on the electric power. Specifically, the amount of Joule heat is proportional to the product of resistance R and the square of current I, and thus, the amount of heat produced can be adjusted by utilizing this relationship. A temperature for cauterization of soft tissue around an incised part lies for example between 50° C. and 100° C. inclusive, or is preferably equal to or higher than 70° C.
Next, the shape memory-processed surgical needles will be described more specifically.
Each of the surgical needles having the shapes illustrated in
Incidentally, besides the embodiment of the shape memory processing and shaping illustrated in
As illustrated in
As illustrated in
Here,
As illustrated in
The surgical needle 12 may pierce through the incised part while rotating from one side thereof toward the other side thereof, or may suture the wound while rotating along the incised part. Details will be described later.
In the embodiments illustrated in
As illustrated in
After the entry of the leading end 12a of the surgical needle 12 into the other side of the incised part, a current is passed through the surgical needle 12 via the forceps or the tweezers. When energization starts, heat is produced according to metal resistance of the shape memory alloy which forms the surgical needle 12. When the temperature of the surgical needle 12 rises to the transformation point or higher by the produced heat, the spiral pitch becomes narrower, and the surgical needle 12 returns from the spiral shape to the coil shape. In addition, the wound can be cauterized by further energization.
In
In the present invention, the shape memory alloy is shape memory-processed in such a manner that the spiral pitch becomes narrower, and the shape memory alloy may be shape memory-processed in such a manner that the curvature radius of the spiral becomes smaller (see
Also, the surgical needle 12 of the present invention may be used for a spot-shaped incised part or wound, as illustrated in
Next, description will be given with reference to
As illustrated in
As described above, the surgical needle of the present invention can be used in endoscopic surgery or robotic surgery as well as manual operation. There are various instruments for the endoscopic surgery and various devices for use in the robotic surgery, and, for example, when ligating an incised part or a wound, a person who performs surgery is required to have highly technical skill; however, the use of the surgical needle of the present invention enables achieving easy and quick ligation of the incised part or the wound. Further, according to the surgical needle of the present invention, not only ligation but also cauterization can be simultaneously performed. For example, an operation for ligating the incised part has heretofore been complicated; specifically, one end of a thread is held by one of the left and right forceps so as to form a ring, and the other end of the thread is passed through the ring by the other forceps. However, the use of the suture instrument of the present invention enables easily closing the incised part.
Also, the surgical needle of the present invention is of a stay type, does not need a thread for suture, eliminates a need to thread a suture needle, involved in the conventional suture needle, and enables providing a medical suture instrument which achieves greater ease of use. Also, suture and cauterization of a wound can be simultaneously performed, and a treatment effect which is not to be found in the prior art can be expected.
2 surgical needle
2
a leading end
2
b rear end
4 surgical needle
6 surgical needle
12 coil-shaped surgical needle
12
a leading end
12
b rear end
40 tube
40
a opening
50 forceps
Number | Date | Country | Kind |
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2011-249366 | Nov 2011 | JP | national |
Filing Document | Filing Date | Country | Kind |
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PCT/JP2012/079638 | 11/15/2012 | WO | 00 |