Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Reexamination Certificate
1999-11-02
2001-09-18
Nguyen, Anhtuan T. (Department: 3763)
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
C604S164070, C604S164130
Reexamination Certificate
active
06290675
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a device for withdrawing a catheter or a probe from a body cavity or a body vessel, with a drive which is preferably a friction drive and engages the axially movable part of the catheter.
BACKGROUND OF THE INVENTION
Catheters or probes are increasingly used in invasive medicine. Such catheters or probes enable body cavities or the vascular system to be analyzed or treated, e.g. intravascular ultrasonic probes being used in diagnostic medicine. While classical angiography only enables changes in longitudinal section and in particular stenoses in blood vessels to be identified, information about the condition of vascular walls can be successfully obtained with such intravascular ultrasonic catheters. In particular, information about calcification, lipoid or fibrotic structures of vascular walls can be obtained with such intravascular ultrasonic catheters, which information in particular serves as a check following interventions, such as, e.g., a stent implantation, to determine whether there are vascular wall injuries or not. Besides intravascular ultrasonic catheters, in which at least one piezoelectric crystal is arranged at the probe head to obtain an image, probes have already been used for treatment, such as, e.g., for intravascular radiation. When a so-called imaging catheter is equipped with only one crystal to obtain an image of the internal wall of a vessel, it is required for completely imaging the vascular wall to rotate this catheter about its axis during withdrawal, so that the image can be obtained as a spirally developed view of the vascular wall. Besides a regulated or constant number of revolutions, a regulated or constant speed during withdrawal of the catheter is a prerequisite. Besides such rotatably driven imaging catheters, there are also known structures having a plurality of crystals which are scanned in a corresponding phase. In such so-called “phased array” catheters, the rotation of the catheter can be omitted. However, an unavoidable prerequisite for a reproducible evaluation of the images is again a defined, in particular constant driving speed during withdrawal of the catheter. For intravascular radiations, too, a uniform feed is essential for the exact dosage. Moreover, during the uniform feed a concentration or ion gradient can be determined in vessels and organs.
The hitherto known devices for withdrawing catheters are relatively heavy and large. In rotating intravascular ultrasonic catheters the heavy motor required for rotational drive is then placed in a corresponding holding device and moved in the longitudinal direction of the catheter together with the axially movable part of the catheter. At the operating table there is hardly any room for such large and heavy devices, so that their handling is relatively laborious. Moreover, such devices usually cannot be sterilized without additional measures, and it is therefore necessary to use them in a corresponding sterile package, which further complicates their handling. Moreover, these known heavy and large devices are very expensive and usually can only be used in connection with a specific drive, e.g. for an intravascular ultrasonic catheter.
NL 10 00 685 C2 shows and describes a device for the controlled movement of a catheter, which comprises a resilient frame open on one side, in which a driving device connected with one end of the frame, such as, e.g., an arm or a pinion, cooperates with the catheter passed into openings in the frame. The frame is compressed manually, with the catheter being moved through the driving device. An adjusting screw enables the compression to be limited and thus a defined stroke and a defined path of movement of the catheter to be adjusted. Additionally, electric contacts are provided at the frame, with which a signal corresponding to the movement of the catheter can be produced during the compression of the frame.
U.S. Pat. No. 4,233,991 A shows and describes a device for withdrawing a urethral catheter, which comprises withdrawing the catheter through a spindle drive connected to a motor. The catheter is connected to the spindle drive via clamping devices.
SUMMARY OF THE INVENTION
The object of the invention is to provide a small and multi-purpose device for withdrawing a catheter, which enables different catheters to be safely driven for different purposes in the same way so as to withdraw the catheter. Besides very small sizes, the device according to the invention must also enable a correspondingly simple handling and be adaptable to different catheters or probes without extensive adaptations. To achieve this object, the device according to the invention essentially consists in that the drive comprises at least one member, which is mounted on a shaft or the like extending transversely to the direction of pull, which member cooperates with at least a counter-member, such that in operation the catheter or probe is held between said members, and that said at least one member is connected to a driving means for actuating said at least one member. In a preferred embodiment of the device according to the invention the drive is formed by at least one roller which is mounted for rotation around a shaft extending transversely to the direction of pull, which roller cooperates with at least one spring-loaded counter-roller, the rollers enclosing the catheter or the probe, and the at least one roller is connected to a driving motor. Owing to the fact that a friction drive is used, in which the withdrawable part of the catheter or the probe is gripped and conveyed between at least two rotating rollers, a substantially shorter and smaller device can be used for any path of movement when withdrawing a catheter or a probe, while the separate simultaneous rotational movement of such a withdrawing part is not adversely affected. Owing to the fact that one of the rollers is pressed in a spring-loaded fashion against at least one driven roller, the feeding or withdrawing movement of the catheter can be controlled in a very exact manner, while also the driving motor and, if required, the energy supply can be accommodated in the correspondingly small device. In principle, this drive can also be a crawler drive or, e.g., a drive with a driven roller which cooperates with two spring-loaded rollers, so as to obtain as gentle a friction engagement as possible, with a high transmission of pull.
The structure is advantageously of such a type that the driving motor is connected to the roller or rollers via a driving gear. Thus the requirements can be met with very small driving motors which rotate at a correspondingly higher number of revolutions, while the force required for withdrawing the catheter is guaranteed by the gear reduction.
The object of providing a small device is guaranteed in a very simple,manner in that the axis of the driving motor is arranged substantially parallel to the direction of pull in a housing carrying the rollers and that the roller or rollers is or are driven via a spindle drive with a shaft crossing the axis or axes of the roller or rollers. In such a structure the total drive for withdrawing a catheter or a probe can be accommodated in a very small housing, which device, in view of its simple structure, can be formed as a disposable device at correspondingly low cost. For repeated use of the same drive, a sterilization should be effected. The use of a spindle drive also permits the arrangement of a very small driving gear. In a a small housing several transmission steps can be provided between the driving motor and the spindle, so that a correspondingly large gear reduction can be achieved between the motor and the driving spindle, as a result of which the normally desired linear driving speed can be exactly maintained between 0.25 and 1 mm/sec.
In view of the small sizes the structure can advantageously be of such a type that the driving motor is connected to a power source disposed in the housing, which power source may be, e.g., a battery or an accumulator. The battery or accumulator may be arranged in a
Brenner Werner
Glogar Dietmar
Hassan Ali
Petrović Dragan
Vujanic Aleksandar
Endosonics Corporation
Leydig , Voit & Mayer, Ltd.
Nguyen Anhtuan T.
Thompson Michael
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