JPH056029B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a drive mechanism made of a shape memory alloy used as a drive means for changing the direction of the distal end of a medical tube for injecting a contrast medium into the pancreatic duct or bile duct, for example.

For medical diagnosis, the method of injecting a contrast medium into the pancreas and bile duct to perform X-ray photography is extremely important.
In this case, as a method for injecting a contrast medium into the pancreas and bile duct, a method is used in which a contrast medium injection tube is orally introduced through an insertion channel of an endoscope. In other words, the tip of the contrast medium injection tube is guided into the duodenum through an endoscope, and the tip of the tube is inserted through the papilla into the pancreas and bile duct, and then the contrast medium is injected through the tube. ing.

However, the pancreatic duct and bile duct, especially the bile duct, run upwards, so when inserting the contrast agent injection tube, press the forceps elevator of the endoscope against the tip of the tube and squeeze. Therefore, the tube cannot be inserted unless it is bent and the tip of the tube is aligned with the direction of travel of the bile duct. Therefore, conventional contrast medium injection tubes are made of synthetic resin such as Teflon (registered trademark), which is relatively easily bent.

In this way, the contrast medium injection tube is inserted into the bile duct, but the opening of the bile duct at the papilla is extremely narrow, and the direction of travel of the bile duct varies depending on each case, so it is usually not clear. Therefore, the degree of bending of the contrast medium injection tube often depends on experience and intuition. However, in reality, it is often extremely difficult to insert the tube because the direction of the bend does not match the running direction of the bile duct. In such cases, the tube for contrast medium injection has to be pulled out from the insertion channel of the endoscope, the curvature is removed by hand, and the tube is reinserted and the operation is repeated.

In addition, when inserting a contrast agent into the next pancreatic duct after injecting a contrast agent into the bile duct, the direction of travel of the pancreatic duct is different from the direction of travel of the bile duct, so pull out the contrast agent injection tube from the insertion channel and bend it manually. I try to do this after removing the . In other words, in the conventional case, it was necessary to repeatedly insert and remove the contrast medium injection tube each time, which was extremely troublesome, and the procedure time was considerably prolonged, placing a heavy burden on the operator and the patient.

Therefore, once inserted into the body in this way,
It is only necessary to be able to easily correct the bending of the distal end of the medical tube while the tube remains inserted, without having to take the trouble of pulling the medical tube out of the body, so that the next operation can be performed quickly and easily. It would be desirable to provide a drive mechanism for this purpose.

The present invention has been made focusing on the above circumstances,
The object thereof is to provide a drive mechanism made of a shape memory alloy that can be used to drive, for example, to change the direction of the tip of a medical tube by using a drive member made of a shape memory alloy.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. In this embodiment, a drive mechanism made of a shape memory alloy is applied to drive the tip of a contrast agent injection tube to curve.

Reference numeral 1 in FIG. 1 is a tube for injecting the contrast medium, and this tube 1 is made of material that is harmless to living bodies, such as polyamide, tetrafluoroethylene, or a copolymer of tetrafluoroethylene and hexafluoropropylene.
It is made of synthetic resin with a small coefficient of friction. A cylindrical base 2 is coaxially attached and fixed to the base end of the tube 1. The tube 1 is attached to the side of the cap 2 through the internal hollow part of the cap 2.
An injection port 4 having an injection hole 3 communicating therein is provided. A knob 7 of a core body 6 is detachably attached to the rear end opening 5 of the cap 2. The core body 6 is made of a relatively rigid material such as synthetic resin, and the knob 7 is adhesively fixed to the rear end of the core body 6.

The core body 6 is inserted into the tube 1 through the base 2, but a gap is formed between it and the inner surface of the tube 1, which is large enough to allow the contrast medium to flow, as will be described later. . In addition, the core body 6
without its tip penetrating tube 1,
The length is set to reach near the rear end of the tip portion 1a of the tube 1. However, since the core 6 is not located within the tip 1a of the tube 1, the tip 1a can easily and freely bend without being affected by the core 6. The shape has become curved.

Further, within the thickness of the distal end portion 1a of the tube 1, a plurality of biasing drive members 8 formed in a linear shape are embedded in parallel along the longitudinal direction of the tube 1, as shown in FIG. Arranged. Each drive member 8 is made of a shape memory alloy. As this shape memory alloy, a material such as a Cu-Zn-Al alloy or a Ti-Ni alloy is used, for example. The driving member 8 becomes straight when the shape memory alloy is the matrix phase (high temperature phase), and even if the tip portion 1a is curved, it is biased into a straight line. There is. Furthermore, if an external force is applied at room temperature (body temperature) to cause plastic deformation,
A martensitic transformation occurs to form a martensitic phase. In addition, since it is used for medical tubes inserted into the body, the shape memory alloy used must have a temperature Af at which the reverse transformation from martensitic phase to matrix phase ends, for example, 50°C. ing.

On the other hand, as shown in FIG. 2, the tips of separate lead wires 9, 9 are connected to the rear ends of two upper and lower driving members 8 buried within the thickness of the tip portion 1a. Further, the tips of the two drive members 8 are connected by another lead wire 10. In other words, the two driving members 8... are connected to the lead wires 9, 9, 1
The driving members 8 are connected in series by the driving members 8 so that current flows over the entire length of the driving members 8.
Furthermore, as shown in FIG.
is led to the rear end of the tube 1 through the wall thickness of the tube 1, and then led out to the outside, and is connected to the power supply 11 and the energization operation switch 1 in the external power supply circuit.
Connected to 2. By closing the switch 12, a current is supplied to the drive members 8 connected in series through the lead wires 9, 9, 10, thereby forming a means for heating the drive members 8 with Joule heat (resistance heat). are doing.

Next, a method of using the contrast medium injection tube 1 will be explained with reference to FIGS. 4 to 6.

First, the tube 1 is guided through the insertion channel 15 of the endoscope 14, which has been introduced into the descending limb 13 of the duodenum, and its distal end 1a is led out into the descending limb 13 of the duodenum. Furthermore, the bile duct 17 is
It has a bending habit that matches the direction of travel. After this, as shown in FIG.
Insert. However, since the opening of the bile duct 17 is extremely narrow, the running direction of the bile duct 17 cannot be clearly known, and therefore, the curve of the distal end 1a tends to not match the running direction of the bile duct 17. In such a case, it is very difficult to insert it as is. Therefore, if the degree of bending is small, it is better to make the bending habit stronger, but if the bending is too large, close the switch 12 of the external power supply circuit and connect the lead wires 9, 9, 1.
A current is supplied to the drive members 8 made of shape memory alloy through the drive member 8 through the drive member 8 made of a shape memory alloy. As a result, the drive members 8 connected in series are heated by the Joule heat generated by themselves. The shape memory alloy that forms the drive members 8 is in a martensitic phase when it is bent, but when it is heated and reaches a reverse transformation end temperature Af, for example 50°C, its shape memory is retained. As a result, a shape restoring force in the same direction that tends to straighten is generated, forcing the tip 1a to become straight. Therefore, open the switch 12, and after cooling down the forceps elevator stand 1.
6, etc., make an appropriate bend again and bend the tip part 1.
a into the bile duct 17. After it is inserted securely, a syringe (not shown) or the like is connected to the injection port 4, and the contrast medium is press-fitted.

After the contrast medium has been injected into the bile duct 17, if the contrast medium is to be further injected into the pancreatic duct 18, the tube 1 can be inserted into the insertion channel 15 of the endoscope 14, and the external power circuit switch can be turned on. 12 is closed, and current is supplied to the driving members 8 to heat them in the same manner as described above. As a result, the driving member 8...
tries to be straight and makes the tip 1a straight. Then, the forceps are inserted into the pancreatic duct 18 with an appropriate bend using a forceps lifter 16 or the like.

According to the above configuration, the driving member 8 made of a shape memory alloy that straightens the leading end when heated is provided at the tip 1a of the tube 1, and the driving member 8 can be heated by passing an electric current through the driving member 8.
The bending tendency of the distal end portion 1a can be easily removed without pulling out the tube 1 itself from the body cavity. In addition, the burden on both the patient and the operator can be greatly reduced.

Further, the plurality of drive members 8... are connected to lead wires 9,
Since they are connected in series by 9 and 10, the overall electrical resistance of the drive members 8 can be increased, and current can flow over the entire length of the drive members 8. Thereby, when heating the driving members 8 to the transformation point Af, only a small current is required. Furthermore, the power supply can be made smaller. Furthermore, since the drive members 8 are arranged so that their shape recovery forces are in the same direction, their deformation drive force can be increased.

As explained above, in the drive mechanism of the present invention, a plurality of drive members are connected in series by lead wires, so that the overall electric resistance of the drive members can be increased, and the drive mechanism of the drive members is Current can be passed along the entire length. Thereby, when heating the drive member to the transformation point, only a small current is required. Moreover, since each drive member has its shape recovery force directed in the same direction, its drive force can be increased.

[Brief explanation of drawings]

Fig. 1 is an overall perspective view showing an embodiment of the present invention, Fig. 2 is a side sectional view of the vicinity of the distal end of the embodiment, and Fig. 3 is a side sectional view of the proximal portion of the embodiment. , and FIGS. 4 to 6 are explanatory diagrams of the state of use, respectively. DESCRIPTION OF SYMBOLS 1...Tube, 1a...Tip part, 8...Driving member, 9...Lead wire, 10...Lead wire, 11
...Power supply, 12...switch.

Claims (1)

[Claims] 1 A plurality of drive members made of shape memory alloy are arranged and provided so that the shape recovery forces are in the same direction,
A shape memory alloy characterized in that a lead wire is provided to connect each drive member in series, and means is provided for supplying current to the drive member through the lead wire to heat the drive member made of the shape memory alloy. A drive mechanism consisting of.