DE102015202967B4 - Flow restrictor for a fluid line in a phacoemulsification system - Google Patents

Abstract

Flow restrictor for a fluid line in a phacoemulsification system, comprising: - a pressure generating device with a pressure piece for applying a compressive force to the fluid line, and - a counter-holder, which is adapted to receive the pressure applied by the pressure piece on the fluid line pressure force, the pressure piece or the Contra-holder in a zone which is brought into contact with the fluid conduit, having a recess which has a variable cross-sectional area in its longitudinal extent.

Description

The invention relates to a flow restrictor for a fluid line in a phacoemulsification system and to a phacoemulsification system having such a flow limiter.

There are several surgical techniques for treating cataract clouding, which is called cataract in medicine. The most widely used technique is phacoemulsification, in which a thin hollow needle is inserted into the eye lens and excited to ultrasonic vibrations. The vibrating hollow needle emulsifies in its immediate vicinity the lens such that the resulting lens particles can be sucked through a conduit by means of a pump. In this case, a flushing fluid (irrigation fluid) is supplied, wherein the suction of the particles and the fluid is carried out by an aspiration line. Once the lens has been completely emulsified and removed, a new artificial lens can be placed in the empty capsular bag so that a patient treated in this way can regain good vision.

When crushing the eye lens by an ultrasonically vibrating hollow needle, it is unavoidable that during surgery a relatively large lens particles so in front of the tip of the hollow needle comes to rest that this needle tip or its suction is blocked. This condition is called occlusion. In such a case, a commonly used peristaltic pump in the aspiration line builds a multiple stronger suction pressure compared to an occlusion-free operation. In addition, a strong energy input for the movement of the hollow needle done, so that the hollow needle clogging lens particles is shattered. Alternatively, a reversal of the direction of the peristaltic pump can remove the lens particles from the needle tip again, so that again a conventional suction of the fluid and the small lens particles can be done. In such a moment, an occlusion is thus broken, whereby the previously applied high negative pressure decreases very rapidly. The resulting suction can lead to not only small lens particles and fluids are drawn to Aspirationsleitung, but also a part of the capsular bag comes into contact with the hollow needle. If the capsular bag is punctured, this leads to considerable complications for the patient, which must be avoided at all costs. In addition, in the suction, a large amount of fluid can be sucked out of the anterior chamber of the eye, so that there is a risk that the eye collapses. Again, this can lead to significant complications for the patient, which must be avoided at all costs.

If a pressure pump such as a venturi pump is used, a flow rate in a fluid line results directly from the set negative pressure, which depends on the resistance in the fluid line. If there is an occlusion breakthrough as described above, a high volume flow can also be extracted at a given negative pressure in the aspiration line, as a result of which a strong pressure fluctuation can occur in the eye, so that the stability of the eye chamber is endangered. This can lead to significant complications for the patient, which must be avoided at all costs.

In order to make congestion of the hollow needle occur as rarely as possible, an operator aims for the highest possible negative pressure in the aspiration line, so that lens particles do not stick in front of the hollow needle, but can be sucked off. However, there is a risk that too much fluid is sucked out of the anterior chamber of the eye and the anterior chamber already collapses without an occlusion breakthrough. The surgeon is thus forced to work with a relatively low negative pressure in the aspiration line, so that the flow in the aspiration line is not too large.

In DE 10 2012 018 983 A1 "In the ophthalmic surgical apparatus for phacoemulsification, which has an aspiration line, a suction vacuum pump and a flow restrictor, wherein the flow rate is adjustable to an amount ranging from 5 milliliters per minute to 100 milliliters per minute, and the flow restrictor is located upstream of the vacuum suction pump when viewed in the suction direction is.

In US 2005/0 054 971 A1 For example, a method and apparatus for providing modulated fluid delivery and aspiration during a surgical procedure, such as phacoemulsification, is described.

• – eine Aspirationsleitung mit einem distalen und proximalen Ende und einem Aspirationsanschluss, der in dem distalen Ende definiert ist;
• – eine Fluidtransportvorrichtung, die mit dem proximalen Ende der Aspirationsleitung wirkverbunden ist;
• – einen Flussbegrenzer, der mit der Aspirationsleitung zwischen der Fluidtransportvorrichtung und dem Aspirationsanschluss wirkverbunden ist;
• – einen ersten Vakuumsensor, wobei der erste Vakuumsensor mit der Aspirationsleitung zwischen dem Anschluss und dem Begrenzer wirkverbunden ist; ein zweiter Vakuumsensor mit der Aspirationsleitung zwischen dem Begrenzer und der Fluidtransportvorrichtung wirkverbunden ist; und

das System ein Computerprogrammprodukt aufweist, das ein computernutzbares Medium mit einer Befehlsfolge enthält, die, wenn sie durch einen Prozessor ausgeführt wird, den Prozessor dazu bringt, ein Verfahren zum Messen eines Druckunterschieds zwischen dem ersten und zweiten Vakuumsensor auszuführen.In US 2008/0 125 698 A1 An aspiration system is described which comprises:

• An aspiration line having a distal and proximal end and an aspiration port defined in the distal end;
• A fluid transport device operatively connected to the proximal end of the aspiration line;
• A flow restrictor operatively connected to the aspiration line between the fluid transport device and the aspiration port;
• - A first vacuum sensor, wherein the first vacuum sensor with the aspiration line between the terminal and the limiter is actively connected; a second vacuum sensor is operatively connected to the aspiration line between the restrictor and the fluid transport device; and

the system includes a computer program product including a computer usable medium having a thread that, when executed by a processor, causes the processor to perform a method of measuring a pressure differential between the first and second vacuum sensors.

It is therefore an object to provide a device with which no occlusion breakthrough pressure fluctuations in the aspiration and in the eye of a patient can occur. With the device, it should also be possible to be able to adjust the flow or volume flow in an aspiration line in a simple manner very fine and in addition to a very low value. The device should also enforce as little as possible with suctioned lens particles and clog. The device should also allow that at a relatively high suction pressure only a low flow in the aspiration line occurs. It is a further object to provide a phacoemulsification system with such a device.

The object of the device is achieved by the subject matter of patent claim 1. Advantageous developments of the invention are the subject of the dependent claims. The object of the phacoemulsification system is solved by the subject matter of patent claim 9.

• – eine Druckerzeugungsvorrichtung mit einem Druckstück für das Aufbringen einer Druckkraft auf die Fluidleitung, und
• – einen Gegenhalter, welcher geeignet ist, die von dem Druckstück auf die Fluidleitung aufgebrachte Druckkraft aufzunehmen,

wobei das Druckstück oder der Gegenhalter in einer Zone, die mit der Fluidleitung in Kontakt gebracht ist, eine Aussparung aufweist, die in ihrer Längserstreckung eine veränderliche Querschnittsfläche besitzt.The device according to the invention is a flow restrictor for a fluid line in a phacoemulsification system, comprising:

• - A pressure generating device with a pressure piece for applying a compressive force on the fluid line, and
• A counter-holder, which is suitable for receiving the pressure force applied by the pressure piece to the fluid line,

wherein the pressure piece or the counter-holder in a zone which is brought into contact with the fluid line, a recess which has a variable cross-sectional area in its longitudinal extent.

The flow restrictor has a pressure generating device with a pressure piece which is suitable for applying pressure to a fluid line, such as an aspiration line. The pressure leads to a deformation of the fluid line, if the fluid line can not escape, but is held by a counter-holder in a predetermined position. The pressure piece or the counter-holder is not provided in a zone which is brought into contact with the fluid line, with a substantially planar surface, but the pressure piece or the counter-holder has in the contact zone on a recess which in its longitudinal extent a variable cross-sectional area has. This makes it possible, when applying a compressive force on the fluid line to deform them so that only a very small cross section of the fluid line for the flow of a fluid is achieved. The variable cross-sectional area of the recess is advantageous because, depending on the position where the pressure is applied to the fluid line, a different sized remaining cross-sectional area in the fluid line adjusts.

This has the effect that, in the event of an occlusion breakthrough, a flow can be limited so much that there is no longer the danger of sucking off too large an amount of fluid from the anterior chamber of the eye. The known dangerous pressure fluctuation in the eye is reduced considerably. If due to the achieved small cross-sectional area in the fluid conduit, a lens particle should clog the conduit, by rapidly reducing the pressure force on the fluid conduit whose cross-sectional area can be increased rapidly. So no filter or the like needs to be cleaned, so there is no longer interruption of the operation. When the compressive force applied to the fluid conduit produces a relatively small cross-sectional area within the fluid conduit, it is ensured that the flow in the fluid conduit is limited so that a relatively high suction pressure may be applied without causing instability of the anterior chamber of the eye.

The stated tasks are thus completely solved by the flow restrictor according to the invention.

It should be noted that the flow restrictor is not part of the suction pump or pressure pump. The flow restrictor is also not in direct contact with a part of such a pump. In particular, the pressure piece is not a ball or roller of a peristaltic pump. The flow restrictor can thus be installed independently of a pump used in a Phakoemulsifikationssystem. The flow restrictor may be provided for an aspiration line or an irrigation line.

In one embodiment of the invention, the pressure piece or the counter-holder is displaceable in a direction parallel to the longitudinal extent of the fluid line or in a direction with an equidistant distance from the fluid line. Thus, it is possible to achieve a rapid change in the cross-sectional area in the fluid line, as a function of the Zone in which the pressure force is applied to the fluid line, another cross-sectional area of the recess of the counter-holder or the pressure piece comes into effect.

Preferably, the recess is formed by a groove which widens steadily in its longitudinal extent and / or deepened. Such a recess is easy to produce. In addition, if the contact of the pressure piece or the counter-holder is displaced to the fluid line in a direction parallel to the longitudinal extension of the fluid line, results in a linear change in the cross-sectional area in the fluid line, so that a simple adjustment of the cross-sectional area in the fluid line is possible.

Preferably, the cross section of the channel is triangular, circular arc or at least partially parabolic. Such geometries allow good guidance of the fluid conduit when a compressive force is applied. An at least partially parabolic cross-section is advantageous because at the edges of the recess a smooth transition to the adjacent plane is possible and the fluid line rests against a sharp edge when compressed.

If the ratio of the depth of the channel to its length is less than 1:10, preferably less than 1:20, a very fine and very accurate adjustment of the fluid line cross section can be achieved.

According to a further embodiment of the invention, the pressure piece has at least partially a round cross-section. Such a round cross-section results in the application of a compressive force on the fluid line to a uniform decrease in the pressure force in the edge region of the zone, which is in contact with the fluid line. This mechanically protects the fluid line and reduces the risk of crack initiation due to sharp edges. Preferably, the pressure piece provided with an at least partially round cross-section is displaceable in the longitudinal extent of the fluid line. This can be changed by unrolling the pressure piece of the fluid line cross section in a simple manner. Preferably, the pressure piece is designed as a roller. Thus, the pressure piece with high surface quality and can be produced in a simple manner.

Preferably, a circumferential line of the pressure piece is designed such that the distance from the axial center of the pressure piece along a radial line grows to a peripheral point proportional to an increasing tilt angle. By a pivoting movement of such a pressure piece, a pressing force can be linearly increased or reduced to the fluid line in a simple manner, wherein no transverse movement of the pressure piece in the longitudinal extension of the fluid line is required. The pivotal movement of the pressure piece is preferably achieved by an electric motor or by hydraulics or pneumatics, so that a change in the fluid line cross-section is very quickly possible. In the event of a blockage in the fluid line, the blockage can thus be quickly eliminated by a very rapid enlargement of the fluid line cross section.

Further advantages and features of the invention will be explained with reference to the following drawings, in which:

1 a schematic representation of a Phakoemulsifikationssystems with a flow restrictor according to the invention;

2 a schematic representation of the principle of operation of the flow restrictor according to the invention;

3 a schematic representation of a first embodiment of the flow restrictor according to the invention in a front view;

4 a schematic representation of a second embodiment of the flow restrictor according to the invention in a front view;

5 a schematic representation of the first embodiment of the flow restrictor according to the invention, when no pressure force is exerted on a fluid line;

6 a schematic representation of the first embodiment of the flow restrictor according to the invention, when a compressive force of medium height is exerted on the fluid line;

7 a schematic representation of the first embodiment of the flow restrictor according to the invention, when a very high pressure force is exerted on the fluid line;

8th a diagram relating to the dependence of the depth of a recess in a pressure piece or a counter-holder of the flow restrictor according to the invention to the associated fluid line cross-section;

9 a perspective view of a first counter-holder with a recess which is used in the first embodiment of the flow restrictor according to the invention;

10 a perspective view of a second counter-holder with a recess which is used in the first embodiment of the flow restrictor according to the invention;

11 different geometries for a recess in a counter-holder of the flow restrictor according to the invention in the front view;

12 a perspective view of a flow restrictor according to the first embodiment with a pressure piece, which has a round cross-section;

13 a side view of a flow restrictor according to a third embodiment; and

14 a cross-sectional view of in 13 shown flow restrictor.

In 1 is a schematic representation of a phacoemulsification system 100 with a flow restrictor according to the invention 1 shown. The phacoemulsification system 100 has a container 2 with an irrigation fluid 3 on, which along an irrigation line 4 to a handpiece 5 with a hollow needle 6 is directed. The hollow needle 6 allows smashing (emulsification) of a lens by an ultrasonic oscillatory motion 7 one eye 8th , The smashed lens particles become fluid through the hollow needle 6 into an aspiration line 9 conveyed, wherein the suction pressure by a pump 10 provided. The extracted lens particles and the aspiration fluid then pass into a collecting container 11 , Between the handpiece 5 and the pump 10 is the flow restrictor according to the invention 1 which limits the flow rate or the volume flow in the aspiration line 9 causes. The flow limiter 1 is an independent component and not part of the pump 10 , The flow limiter 1 is also not directly with the pump 10 interacts, but works regardless of the pump used 10 ,

The operating principle of the flow limiter 1 is in 2 shown. One in the aspiration line 9 flowing aspiration fluid 91 gets to a throttle 20 with a length L and a diameter D. The aspiration fluid 91 jams in front of the throttle 20 so that a pressure difference between the pressure p1 before the throttle 20 and the pressure p2 after the throttle 20 is present.

mit Δp als Druckdifferenz, Q_D als Volumenstrom, η als dynamischer Viskosität des Fluids, L als Länge der Drossel bzw. des engen Querschnittes und R als Radius der Drossel bzw. des engen Querschnittes kann die Druckdifferenz innerhalb einer Hohlnadel 6 berechnet werden. Innerhalb der Hohlnadel 6 mit einem Innendurchmesser von üblicherweise 0,5 mm bzw. einem Innenradius von R = 0,25 mm und einer Länge von L = 30 mm entsteht bei einem Volumenstrom in der Hohlnadel von etwa Q_D = 60 ml/min und einer dynamischen Viskosität von Aspirationsfluid in Höhe von η = 1,0 kg/ms eine Druckdifferenz in Höhe von Δp = 150 mmHg, wobei 1 mmHg etwa 133,3 kg/ms² ist.It is believed that a hollow needle 6 how a throttle works, the following relationships apply: According to the equation

with Δp as the pressure difference, Q _D as the volume flow, η as the dynamic viscosity of the fluid, L as the length of the throttle or the narrow cross-section and R as the radius of the throttle or the narrow cross-section, the pressure difference within a hollow needle 6 be calculated. Inside the hollow needle 6 with an inner diameter of usually 0.5 mm or an inner radius of R = 0.25 mm and a length of L = 30 mm is formed at a volume flow in the hollow needle of about Q _D = 60 ml / min and a dynamic viscosity of Aspirationsfluid in the amount of η = 1.0 kg / ms, a pressure difference of Δp = 150 mmHg, where 1 mmHg is about 133.3 kg / ms ² .

It is further assumed that the aspiration line following the needle 9 also acts as a throttle, the aspiration line 9 has an inner diameter of usually 1.3 mm or an inner radius of R = 0.65 mm and a length of L = 2000 mm, the pressure in the aspiration line is approximately Δp = 215 mmHg. Thus, from the entrance of the hollow needle to the end of an aspiration line, a pressure difference of approximately 365 mmHg builds up when the volume flow 60 ml / min. If a higher r suction pressure is applied, the volume flow increases immediately, since the pressure difference in the hollow needle with subsequent aspiration line in the amount of about 365 mmHg remains unchanged. However, if a surgeon wishes to work with a pressure differential of about 700 mmHg, this can be achieved with the flow restrictor of the present invention. With a throttle length of about L = 5 mm and an inner radius of the fluid line of about 0.15 mm, the pressure difference increases by a further 300 mmHg. With the flow restrictor according to the invention, it is possible to adjust such a pressure difference infinitely and very accurately, with a variation of 0 to about 400 mmHg at a flow rate of 60 ml / min is possible.

A first embodiment of the flow restrictor according to the invention 1 shows 3 , A pressure generating device 21 has a pressure piece 22 on, with a pressure force on a fluid line, here an aspiration line 9 , can be applied. The pressure piece 22 is in a console 25 stored and can move vertically up and down. The pressure piece 22 acts on the aspiration line 9 , which by a counterpart 23 is worn, which is a recess 24 having a depth T. The console 25 is with the backstop 23 coupled.

According to a second embodiment, see 4 , is the recess 24 in the pressure piece 22 provided, whereas the counterpart 23 no recess 24 having. The remaining structure of the second embodiment corresponds to the structure of the first embodiment according to 3 ,

The operation of the flow restrictor 1 is based on the very schematic 5 to 7 explained below. In 5 is this Pressure piece 22 the flow restrictor 1 placed so high that the aspiration line 9 not yet compressed. The depth of the recess 24 is T2, the fluid line cross-sectional area is FA0. When the pressure piece is moved down a distance s ₁ , cf. 6 , causing the aspiration line 9 a compressive force acts, deforms the aspiration line 9 such that the fluid line cross-sectional area decreases to the amount FA1. With increasing downward movement of the pressure piece up to the height s ₂ , the aspiration line 9 further compressed, cf. 7 , The material of the aspiration line 9 It is always better in the recess 24 into, so that in a mutual contact of the Aspirationsleitungsinnenwand in the area 91 a fluid line cross-sectional area FA2 remains. This fluid passage cross-sectional area FA2 is zero when no recess 24 is available. With increasing depth T of the recess 24 Also, the fluid line cross-section FA increases. In 8th is the relationship between the depth T2 of the recess 24 and the associated fluid line cross-sectional area FA2. Generally, it can be said that the profile of the recess 24 in one area 92 the aspiration line 9 repeated in a similar way, cf. 7 , By lowering the pressure piece 22 along the distance s, the free fluid line cross-section FA can thus be accurately adjusted, the depth T of the recess prevents complete closure of the line. Thus, a clogging of the line can be prevented.

9 shows a perspective view of a first counter-holder 23 with a recess 24 , which is a channel that widen and deepen steadily in its longitudinal extension. The depth of the recess 24 begins at zero and increases steadily, so that a variable cross-sectional area A is achieved. The cross-sectional area, starting from the point P0 with an amount of zero, reaches an amount A1 about one third of the length of the channel at the position P1. After approximately another third of the length at the position P2, the cross-sectional area reaches an amount A2 and at the edge of the channel at the position P3 an amount A3, see hatched areas in FIG 9 , So if the aspiration line 9 lies in this groove and the pressure piece 22 at position P2, the aspiration line 9 as compressed as this 7 is shown, the fluid line cross-sectional area reaches an amount FA2 which corresponds approximately to the cross-sectional area A2 of the counter-holder at the position P2, cf. 9 , Depending on the position of the pressure piece 22 over the counterpart 23 can thus be achieved a different size fluid line cross-sectional area, so that the pressure loss in the aspiration line 9 is very finely adjustable.

In 10 is a second counterholder 23 shown, with the depth of the recess 24 in the longitudinal extension of the recess 24 is the same and only the width of the recess 24 changes in the longitudinal direction.

The cross-sectional shape of the recess 24 in a counterholder 23 or a pressure piece 22 can have different geometries. In 11 are different cross-sectional shapes for a recess 24 in a counterholder 23 shown. Advantageously, a triangular cross-section 24A , a circular arc-shaped cross-section 24B or an at least partially parabolic cross-section 24C , These forms are suitable for receiving the aspiration line 9 as it is a good guide for the aspiration line 9 Offer. The recess 24C allows a very smooth transition to the adjacent surface of the counter-holder, see reference numerals 241 so the aspiration line 9 in fully compressed state rests on any sharp edge.

12 shows in a perspective and schematic representation of the pressure generating device 21 with a console 25 which has a horizontal guide groove 27 and vertical guide grooves 28 for the positioning of the pressure piece 22 having. The pressure piece 22 has a round cross section and is designed in the form of a roller. The roller has an axial center M and is in the longitudinal extension of the fluid line 9 by means of the guide groove 27 displaced. The displacement can be through a rotation 29 the roller or by a translational movement 30 the roll done.

13 shows a further embodiment of the flow restrictor 1 in a side view and in 14 in a cross-sectional view with a pressure piece 22 and the compressed aspiration line 9 which is in a recess 24 according to 9 in a counterholder 23 is arranged. The pressure piece 22 has a perimeter 221 , which is designed so that the distance from the axial center M of the pressure piece 22 grows along a radial line to a circumferential point U proportional to an increasing tilt angle φ. The distance thus increases from the amount a1 (distance from M to U1) increasingly to the amount a2 (distance from M to U2), see 13 , By pivoting the pressure piece 22 around the center of the axis M, the aspiration line 9 in a zone 242 in which the pressure piece 22 with the fluid line 9 is thus brought to a predetermined fluid line cross-sectional area FA2 compressed. This is advantageous because a pivoting movement of the pressure piece 22 can be done very quickly, allowing a rapid increase or decrease in the pressure difference in the aspiration line 9 is possible.

The Applicant reserves the right to claim all features disclosed in the application documents as essential to the invention, provided they are novel individually or in combination with respect to the prior art. It is further pointed out that features are included in the individual figures, which in themselves can be advantageous. The person skilled in the art immediately recognizes that a particular feature described in one figure can also be advantageous without taking over further features from this figure. Furthermore, the person skilled in the art recognizes that advantages can also result from a combination of several features shown in individual or in different figures.

Claims (9)

Flow restrictor for a fluid line in a phacoemulsification system, comprising: - A pressure generating device with a pressure piece for applying a compressive force on the fluid line, and A counter-holder, which is suitable for receiving the pressure force applied by the pressure piece to the fluid line, wherein the pressure piece or the counter-holder in a zone which is brought into contact with the fluid line, a recess which has a variable cross-sectional area in its longitudinal extent. Flow restrictor according to claim 1, wherein the pressure piece or the counter-holder is displaceable in a direction parallel to the longitudinal extent of the fluid line. Flow restrictor according to one of the preceding claims, wherein the recess is formed by a groove which widens steadily in its longitudinal extent and / or deepened. Flow restrictor according to claim 3, wherein the cross section of the channel is triangular, circular arc or at least partially parabolic. A flow restrictor according to any one of claims 3 or 4, wherein the ratio of the depth of the trough to its length is less than 1:10. Flow restrictor according to one of the preceding claims, wherein the pressure piece has at least partially a round cross-section. Flow restrictor according to claim 6, wherein the pressure piece in the longitudinal extent of the fluid line is displaceable. A flow restrictor according to any one of claims 6 or 7, wherein a peripheral line of the pressure piece is made such that the distance from the axis center of the pressure piece increases along a radial line to a peripheral point proportional to an increasing tilt angle. Phacoemulsification system with a flow restrictor according to one of claims 1 to 8.

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