Surgical cassette with multi area fluid chamber

Technical Field The present invention relates generally to a surgical cassette intended for use in microsurgical systems, and more particularly to cassettes intended for use in ophthalmic microsurgical systems.

Description of the Related Art [0002] During small surgery, and especially during ophthalmic surgery, small probes are inserted into the surgical site for cutting, removing or performing other tissue activities. During this type of surgery, infusion fluid is usually introduced into the eye, while the infusion fluid and tissue are sucked from the site of the procedure. The suction systems used until now are generally referred to as systems with flow rate control or vacuum control, depending on the type of pump used in the system. Each of these systems has some advantages.

[0003] In suction systems with vacuum control, the desired level of vacuum is set, which system tries to maintain. The flow rate depends on the intraocular pressure, vacuum level and flow resistance in the flow path. Information on the actual flow rate is not available. Suction systems with vacuum control usually use a Venturi or diaphragm pump. Suction systems with vacuum control have the advantages of short response times, control of falling vacuum levels, and good fluid performance when sucking in air, such as during an air / fluid exchange procedure. The disadvantages of such systems include the lack of flow rate information, resulting in high transient flow rate values ​​during phacoemulsification or fragmentation combined with no occlusion detection. Vacuum control systems are difficult to operate in a flow rate control mode due to problems with non-invasive real-time flow rate measurement.

[0004] In suction systems with flow rate control, the desired flow rate to be maintained by the system is set. Suction systems with flow rate control usually use a peristaltic, spiral or vane pump. Suction systems with flow rate control have the advantages of stable flow rates and automatic increase of the vacuum level in the event of occlusion. The disadvantages of such systems are relatively long response times, undesirable intermittent responses in the case of occlusion, when large susceptible components are used and the vacuum cannot be linearly lowered during tip occlusion. Systems with flow rate control are difficult to operate in a vacuum control mode, as time delays in measuring the vacuum can cause instability in the control loop, reducing performance in dynamic operation.

[0005] One of the currently available ophthalmic surgery systems is the MILLENIUM system from the Storz Instrument Company, which includes both a suction system with vacuum control (using a Venturi pump) and a separate suction system with flow control (using a spiral pump). Both pumps cannot be used simultaneously and each requires separate suction piping and a cassette.

[0006] Another currently available ophthalmic surgical system, ACCURUS® from Alcon Laboratories, Inc. It contains both a Venturi pump and a peristaltic pump that work in series. The Venturi pump sucks the material from the treatment site into a small collection chamber. Pump 1

EP 1 996 269B1

V4378PL00 / PJ peristaltic pumps the sucked material from this small collection chamber into a larger collecting bag. The peristaltic pump does not supply the suction vacuum to the treatment site. Therefore, this system works as a system with vacuum control.

[0007] US 5286262 describes a multi-purpose vessel collection that includes a closed vessel with elements for regulating the suction and insulation of the chamber, as well as a collection chamber intended for receiving blood through a tube connected to the wand or surgical drain. The accumulating chamber is divided into a filtered reinfusion chamber with a volumetric scale in the range from a few millimeters to two hundred millimeters, as well as a separate unfiltered chamber for a total volume of several liters. The vessel collection can perform all the conventional functions of a pediatric drain, reinfusion vessel, cardiotomy vessel, general purpose drainage device, or multi-site drainage device.

[0008] US 3742934 describes the construction of a body fluid storage bottle in which the container part is provided with fluid restriction means to obtain a container area with a reduced cross section, so that the initial filling of the lower part of the container, even the introduction of a small amount of fluid , caused a rapid increase in fluid level. In this case and using appropriate scale indicators, small amounts of fluid initially introduced into the bottle can be measured very precisely. Above the lowest, fluid-restricting portion of the bottle structure, the introduction of increasing amounts of liquid will produce a reduced vertical increase in fluid level at the top of the bottle structure.

[0009] US 4444548 describes a suction device for use in draining fluids from surgical wounds or other body cavities, which device comprises a housing having a vacuum chamber, at least a portion of which serves as a storage compartment for sucked fluids. The vacuum pump in the device has an inlet connected to the vacuum chamber to create a vacuum inside it. The storage compartment has an inlet for introducing the sucked fluid into it, and an outlet for emptying the compartment from the fluid is also present. Appropriate means are provided in the compartment to measure the amount of aspirated fluid accumulated in the storage compartment.

[0010] US 5582601 describes a cassette for collecting liquids in fluid suction systems that can be reused after sterilization. This cartridge includes a vacuum hole and a suction hole along the top wall of this cartridge. Suction piping is connected to the suction opening at one end and sits inside the standing retainer at the proximal edge of the upper wall at the opposite end. Inside the cassette contains structures to increase the flow impedance so that liquid is not drawn into the vacuum opening as the fluid level rises. Furthermore, a pivot mechanism located around the hub inside the chamber is present. [0011] Despite the presence of these conventional systems, there is still a need for improved suction and infusion jet automation in an ophthalmic surgical system.

SUMMARY OF THE INVENTION The present invention relates to a surgical cassette having an aspiration chamber according to claim 1. This chamber comprises a lower measuring part for enabling accurate measurements of changes in fluid level, and an upper storage part for enabling

EP 1 996 269B1

V4378PL00 / PJ storage of fluids during surgery. The cross-sectional area of ​​the measuring part is smaller than the cross-sectional area of ​​the storage part.

Brief Description of the Drawing [0013] For a more complete understanding of the present invention and its additional purposes and advantages, reference is made to the following description and the accompanying drawings, in which:

Figure 1 is a schematic diagram illustrating suction control in a microsurgical system;

Figure 2 is a front view of the surgical cassette body; and Fig. 3 is a rear view of the surgical cassette body of Fig. 2.

Detailed Description of Preferred Embodiments [0014] Preferred embodiments of the present invention and their advantages will best be understood by reference to Figs. 1-3 of the drawing, with similar reference numbers designating similar and corresponding elements in the various drawings.

The microsurgical system 10 includes a compressed gas source 12, shut-off valve 14, vacuum proportional valve 16, optional second vacuum proportional valve 18, pressure proportional valve 20, vacuum generator 22, pressure transducer 24, suction chamber 26, level sensor fluid 28, pump 30, opening 32 for collecting bag, suction opening 34, surgical device 36, computer or microprocessor 38, as well as proportional control device 40. The various components of the system 10 are fluidly connected via lines 44, 46, 48, 50, 52, 54, 56 and 58. The various components of the system 10 are electrically connected via connectors 60, 62, 64, 66, 68, 70, 72, 74, 76. The valve 14 is preferably an on / off solenoid valve. The valves 16-20 are preferably proportional solenoid valves. Vacuum generator 22 may be any useful device for generating a vacuum, but is preferably a vacuum module or a Venturi module that generates a vacuum when the shut-off valve 14 and vacuum proportional valves 16 and / or 18 are open and the gas from the compressed gas source 12 is passed through a vacuum generator 22. The pressure transducer 24 can be any useful device for direct or indirect pressure and vacuum measurement. The fluid level sensor 28 may be any useful device for measuring the level of fluid 42 inside the suction chamber 26, but is preferably capable of continuously measuring the level of fluid. The pump 30 may be any suitable vacuum generating device, but is preferably a peristaltic pump, a spiral pump or a vane pump. The microprocessor 38 is capable of performing feedback control, and preferably PID control. The proportional controller 40 may be any suitable device for proportional control of the system 10 and / or surgical device 36, but is preferably a foot operated controller.

[0016] System 10 preferably uses three different methods of suction control, vacuum control, suction control and flow rate control. These methods are described more fully in concurrent application US 11 / 158.238 filed June 21, 2005 and in concurrent application US 11 / 158.225 filed June 21, 2005, both of which are owned together with the present application and are incorporated herein by reference.

EP 1 996 269B1

[0017] In each of these methods, vacuum can be delivered to the surgical device 36 and the aspiration chamber 26 via lines 50, 56 and 58. The aspiration chamber 26 is filled with fluid 42 sucked by the surgical device 36. Fluid 42 contains liquid fluid infusion as well as aspirated ophthalmic tissue. The suction chamber 26 consists of a storage part 130 and a measuring part 132. The storage part 130 has a larger cross-sectional area than the measuring part 132. The cross-sectional area of ​​the storage part 130 is preferably up to 7.5 times greater than the cross-sectional area of ​​the measuring part 132, and most preferably it is about 7.5 times greater than the cross-sectional area of ​​the measuring part 132. The storage part 130 and the measuring part 132 are in fluid communication. The angle between the storage part 130 and the measuring part 132 is most preferably about 90 degrees. As can be seen in Figure 2, the suction chamber 26 is oriented so that the storage part 130 is positioned towards the top of the surgical cassette 100.

[0018] As shown in Figs. 2 and 3, the surgical cassette 100 has a body 102, including an aspiration chamber 26. For clarity, the lid which is sealed on the front side of the body 102 is not shown. For clarity, the platen is not shown which is tightly pressed against the rear side of the body 102. An opening 108 is fluidly connected to the line 50. The input 110 fluidly connects the measuring portion 132 of the suction chamber 26 and the line 56. As stated above, line 56 is fluidly connected to the surgical device 36 via opening 34 and line 58. Input 112 fluidly connects the measuring portion 132 of aspiration chamber 26 and line 52. Suction chamber 26, holes 32 and 34, line 52, 54, 56, opening 108, entrance 110, entrance 112 are preferably integrally formed in the body 102.

[0019] In operation, vacuum is supplied to the suction chamber 26. Fluid 42 is directed from the surgical device 36 to the suction chamber 26. The suction chamber 26 has two functions. One of these functions is to support continuous measurement of the fluid level, which can be used to determine the flow rate. Flow rate measurement can be obtained as follows:

Q ~ Αχ

At where Q is the flow rate, A is the cross-sectional area of ​​the measuring portion 132, DL is the fluid level change 28 measured by the fluid level sensor and Dt means the change in time. It is critical to have accurate and precise measurement of fluid level 42 in the suction chamber 26. To increase the sensitivity of the flow rate measurement, the cross-sectional area of ​​the suction chamber 26 perpendicular to the fluid level sensor 28 must be small. This function is performed by the measuring portion 132 of the suction chamber 26. Fluid 42 enters the measuring portion 132 of the suction chamber 26 via the input 110. The smaller cross-sectional area of ​​the measuring portion 132 allows the fluid level sensor 28 to accurately and accurately determine the fluid level in the chamber suction 26. Another function of the suction chamber 26 is to store an additional amount of fluid 42 to support uninterrupted surgery when replacing the collecting bag (not shown) in fluid communication with the opening 32 for the collecting bag. If during surgery there is a need to store fluid inside the aspiration chamber 26, as is the case during

EP 1 996 269B1

V4378EN00 / PJ collecting bag, the storage part 130 of the suction chamber 26 offers a large cross-sectional area, which gives a large volume for fluid storage.

[0020] The present invention is illustrated by means of an embodiment, and one of ordinary skill in the art can make various modifications. For example, the present invention may be implemented in an infusion chamber 26 of a surgical cassette having both a storage part 130 and a measuring part 132, and not in an aspiration chamber 26 as described above.

[0021] It is believed that the operation and structure of the present invention will be understood from the above description. Although the device and methods shown and described have been described as being preferred, various changes and modifications can be made without departing from the scope of the invention as defined in the following claims.