WO2020225839A1

WO2020225839A1 - Opto-haptic system to measure and represent forces opposing catheter or guide wire penetration into the vascular system for robots for endovascular surgery

Info

Publication number: WO2020225839A1
Application number: PCT/IT2020/050109
Authority: WO
Inventors: Guido Danieli
Original assignee: Guido Danieli
Priority date: 2019-05-08
Filing date: 2020-05-08
Publication date: 2020-11-12

Abstract

Opto-haptic system to measure and represent the forces that oppose the advancement of a catheter or a guide within the endovascular system. The system is obtained essentially by hanging actuator(s) (1), to which hemostatic valves (5) are fixed, to a hinge with a horizontal axis equipped with ball or roller bearings placed on the bed (8) or fixed to a slide (6) inclined towards the patient, and by connecting a force sensor (13) inside the Slave (1) or placed on a fixed point outside the system, to a wire (3) that connects the fixed part and the mobile part, so as to produce a fixed force acting on the sensor, a force that will vary if the guide or catheter meet resistance, while the force variation is shown on the display changing from green to red if the force becomes excessive, or in any other way, including the representation of the numerical value of the force itself.

Description

Opto-haptic system to measure and represent forces opposing catheter or guide wire penetration into the vascular system for robots for endovascular surgery.

State of the Art

It is known that in endovascular surgery, doctors usually manually push guides and catheters into the patient's arterial or venous system, observing their progress under fluoroscopy.

In such conditions, they can notice if the catheter or guide stops, but they are unlikely to appreciate the level of resistance that opposes the motion. Furthermore, robots have been proposed that tend to separate the doctor from the patient, who are currently without a force measurement system. Among these robotic systems one (ROSES, PCT / IT2018 / 050209) was developed by the Calabrian research group I led, and we set ourselves the problem of trying to provide feedback on the intensity of the forces involved.

Fortunately, our actuator that pushes and rotates guides and catheters is small, so it was relatively easy to incorporate the force sensor inside it, and find a way to measure the penetration force alone, without being disturbed by internal friction. In the following we understood that this sensor could also be placed externally.

As is well known haptic systems oppose a force to advancement in order to make the user have the sensation of being in the presence of a body that opposes penetration. However, since the forces in the case in question are very small, it becomes difficult to give the doctor the possibility of actually evaluating the extent of the force itself. For this reason, as already written in the previous patent application 102017000114767 0, a graphic representation of the force itself was thought, through columns on the screen that arise when the force is recorded and grow according to the entity of the force itself, possibly changing color. However in the aforementioned patent the force sensors were placed next to the motor, so that they would have substantially measured the torque delivered by the motor, which must also overcome the resistance of the internal mechanism, which made problematic the separation of the force exerted by the catheter from that of the transmission. However, a way has been found to measure only the feed force, as described in the following paragraph.

Description of the preferred embodiment

The basic idea is first of all to fix the hemostatic valve firmly to the robotic actuator, called Slave, while the Slave itself is fixed by pins fitted with ball bearings to a rod placed above the Slave itself, so as to result tilting in the direction perpendicular to that of motion of the catheter (or guide), or placed on a moderately inclined slide and free to slide in the direction of movement of the same. Then the sensor, placed inside the Slave or outside but firmly fixed to it, is connected to an external fixed point or the Slave is connected to the external sensor but fixed in position, so that the actuation system is slightly tilted forward. In this condition, a rather weak force acts on the sensor due precisely to the maintenance of the Slave in an inclined position. Now all the internal forces of the Slave are self-balanced and the sensor only feels the force transmitted by the wire that keeps it weakly inclined, constant and small, which varies only if there is external resistance to the advancement of the catheter.

This is illustrated in Figure 1, where you can see the Slave (1) hanging from the upper rod (2) and pulled from behind by a wire (3) that connects it to an extension of the rear bar (4), while from the front the hemostatic valve (5) is fixed to the Slave itself.

Similarly, Figure 2 shows the scheme of a pair of Slaves mounted at 90 °, hung from the usual upper pins and pulled by a wire connected to the sensor which is this time placed between the two coupled Slaves, which are as before connected to the hemostatic valves, which if the Slaves are placed in parallel, they should be two connected to a single initial catheter.

Figure 3 shows instead the case of a Slave mounted on a slide with variable inclination (6) and connected to a sensor placed in a fixed position.

Since then, especially in endovascular surgery applications, it is possible that the Slaves must be mounted on a single frame, on which it is also possible to vary the mutual position between them, it is sufficient that this same frame in this case is weakly inclined towards the patient and free to scroll (with very limited travel for safety reasons), fixing the frame to an external sensor (or vice versa the sensor placed on the frame and connected to an external fixed point) to have exactly the same previous situation, possibly keeping account of any dynamic effects due to motion between the Slaves. This is shown in Figure 4 where (7) indicates the free slide to move with a very limited stroke with respect to the fixed support anchored to the bed (8), with (9) the Slave fixed with respect to the slide, with (10) the mobile one, with (11) the rail on which it can move, with (12) the belt that moves it and with (13) the force sensor attached to the fixed support connected to the slide to measure the acting forces.

As previously described, the sensor, connected to the Slave microprocessor or to an independent one, transmits its signals to the system console, called the Master, which shows them on its screen as columns of increasing height.

Finally, Figure 5 shows the display of the Master which shows the column in this case horizontal and increasing as a function of the force applied; obviously the definitive edition may present itself in a different way, just as there may be a column on the right and one on the left to show separately the effects of the advancements of the catheter (on the left) and of the guide (on the right) what matters is to show how it could the entity of the acting force be represented, including a numerical representation of the force measured.

Of course, some form of filtering via software may be applied to the output of the transducer.

Finally, it should be noted that this same measuring system could also be applied as a retrofit to robot actuators for angioplasty or endovascular surgery already on the market.

Claims

Claims.

1. Opto-haptic system for measuring the forces that oppose the advancement of guides and catheters for robots for endovascular surgery, functioning thanks to the fact that the actuator or actuators of the system (Slave in our case), to which it must be fixed also the hemostatic valve, are hung by ball or roller bearings on a hinge with a horizontal axis, or placed on a slide inclined towards the patient, connecting the mobile system constituted by the Slave to a fixed point by cable, interposing a force sensor which it can be both contained in the Slave and placed on the fixed part, so that the direction of motion granted is parallel to the direction of the direction of motion or catheter or guide wire, so as to generate a small force on the wire that holds the Slave tilted which will then be recorded by the sensor and transmitted to the console, called Master, which will display the extent of the variation caused by the friction encountered by the guide or catheter by raising a column on the display, which will be of increasing height as a function of the recorded force, turning from green to red if this force becomes excessive or exposed in numerical form;

2. Opto-haptic system for measuring the forces that oppose the advancement of guides and catheters for robots for endovascular surgery, as in claim 1, in which the support slide of the Slaves, placed in series, admits the relative movement between the themselves, possibly taking into account the dynamic effects generated by the motion.