Patent Description:
The optical elements of the eye include both a cornea (at the front of the eye) and a lens within the eye. The lens and cornea work together to focus light onto the retina at the back of the eye. The lens also changes in shape, adjusting the focus of the eye to vary between viewing near objects and far objects. The lens is found just behind the pupil and within a capsular bag, the capsular bag being a thin, relatively delicate structure which separates the eye into anterior and posterior chambers.

With age, clouding of the lens or cataracts is fairly common. Cataracts may form in the hard central nucleus of the lens, in the softer peripheral cortical portion of the lens, or at the back of the lens near the capsular bag. Cataracts can be treated by the replacement of the cloudy lens with an artificial lens. Phacoemulsification systems often use ultrasound energy to fragment the lens and aspirate the lens material from within the capsular bag. This may allow the capsular bag to be used for positioning of the artificial lens and maintains the separation between the anterior portion of the eye and the vitreous humor in the posterior chamber of the eye.

During cataract surgery and other therapies of the eye, accurate control over the volume of fluid within the eye is highly beneficial. For example, while ultrasound energy breaks up the lens and allows it to be drawn into a treatment probe with an aspiration flow, a corresponding irrigation flow may be introduced into the eye so that the total volume of fluid in the eye does not change excessively. If the total volume of fluid in the eye is allowed to get too low at any time during the procedure, the eye may collapse and cause significant tissue damage. Similarly, excessive pressure within the eye may strain and injure tissues of the eye.

While a variety of specific fluid transport mechanisms may be used in phacoemulsification and other treatment systems for the eyes, aspiration flow systems can generally be classified in two categories: <NUM>) volumetric-based aspiration flow systems using positive displacement pumps (e.g. peristaltic); and <NUM>) vacuum-based aspiration systems using a vacuum source, typically applied to the aspiration flow through an air-liquid interface within a reservoir (e.g. Venturi). Both systems may be incorporated into one treatment system and/or cassette. Cassette ("pack") systems can be used to couple peristaltic pump drive rotors and/or vacuum systems of the surgical consoles to an eye treatment handpiece, with the flow network conduit of the cassette being disposable to avoid cross-contamination between different patients.

To mitigate any such occurrences of cross-contamination between different patients, staff operating a system typically begin each procedure with a fresh cassette and irrigation source prior to each case and monitor the fluid visually throughout surgery. However, conventional configurations do not efficiently provide for easily exchangeable cassettes which can optimally perform certain intended functions. As such, improvements are needed in the art to address these issues.

<CIT> discloses an ophthalmological device which provides suction flushing, having an aspiration function and an infusion function, as well as a replaceable cassette. The device comprises an aspiration conveyor device for motor-driven discharge of liquid from a surgical instrument into a waste container, and an infusion conveyor device for motor-driven supply of an infusion medium from an infusion container to the surgical instrument. <CIT> discloses a cassette having a molded flow channel contained on an elastomeric sheet that is bonded or mechanically attached to a rigid substrate. The flow channel projects outwardly from the exterior of the cassette so that a peristaltic pump having pump head rollers mounted radially from the axis of rotation of the pump motor compress the elastomeric flow channels against the rigid substrate during operation.

The present invention provides a system for distributing fluid in a surgical cassette as recited in claim <NUM>. Optional features are recited in the dependent claims. Aspects, embodiments, examples and methods of the present disclosure which are not claimed per se, are provided for illustrative purposes and are considered useful for giving context to the invention.

The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification. The drawings illustrate disclosed embodiments and/or aspects and, together with the description, serve to explain the principles of the invention, the scope of which is determined by the claims.

It is to be understood that the figures and descriptions have been simplified to illustrate elements that are relevant for a clear understanding of the present invention, while eliminating, for the purpose of clarity, many other elements found in typical surgical, and particularly optical surgical, apparatuses, systems, and methods. Those of ordinary skill in the art may recognize that other elements and/or steps are desirable and/or required in implementing the present invention. However, because such elements and steps are well known in the art, and because they do not facilitate a better understanding of the present invention, a discussion of such elements and steps is not provided herein. The disclosure herein is directed to all such variations and modifications to the disclosed elements and methods known to those skilled in the art.

The figures and descriptions provided herein may have been simplified to illustrate aspects that are relevant for a clear understanding of the herein described apparatuses, systems, and methods, while eliminating, for the purpose of clarity, other aspects that may be found in typical similar devices, systems, and methods. Those of ordinary skill may thus recognize that other elements and/or operations may be desirable and/or necessary to implement the devices, systems, and methods described herein. But because such elements and operations are known in the art, and because they do not facilitate a better understanding of the present disclosure, for the sake of brevity a discussion of such elements and operations may not be provided herein. However, the present disclosure is deemed to nevertheless include all such elements, variations, and modifications to the described aspects that would be known to those of ordinary skill in the art.

Embodiments are provided throughout so that this disclosure is sufficiently thorough and fully conveys the scope of the disclosed embodiments to those who are skilled in the art. Numerous specific details are set forth, such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. Nevertheless, it will be apparent to those skilled in the art that certain specific disclosed details need not be employed, and that exemplary embodiments may be embodied in different forms. As such, the exemplary embodiments should not be construed to limit the scope of the disclosure. As referenced above, in some exemplary embodiments, well-known processes, well-known device structures, and well-known technologies may not be described in detail.

A surgical cassette, also referred to as a medical pack, a fluidic cassette, or simply, a cassette, is used to facilitate irrigation and aspiration during surgical procedures, such as phacoemulsification surgery. The surgical cassette may be inserted and mounted to a surgical console and become part of an overall phacoemulsification surgery system. The surgical cassette may perform a myriad of functions, such as effluent material collection, tube pressure sensing, and control the flow of fluid through tubing encased within the cassette and between a surgical handpiece and a surgical console.

A surgical cassette typically comprises a front plate and a back plate, and may also include a gasket at least partially there between. The front plate and back plate may also be welded together to avoid the use of a gasket or other intermediate portion. Molded within either/or the front plate and the back plate may be pathways for tubing to be inserted thereby creating desired pathways for the tubing around the gasket. In an embodiment where there is a gasket, the gasket may comprise one or more valves and one or more sensors to promote fluid flow through the tubing along the desired pathways. In an embodiment where there is no gasket, any valves known in the art may be used, e.g. rotary valve.

Surgical cassettes may utilize different types of sensors to monitor vacuum, flow, and/or pressure of certain fluid lines or channels during the surgical process. Other single use cassettes may use a low cost pressure diaphragm on the cassette with a console mounted Linear Variable Differential Transformer (LVDT) to measure the deflection of the pressure diaphragm with either a low rate spring pushing the LVDT against the surface of the pressure diaphragm or a magnet coupling the LVDT to the surface of the diaphragm, or a combination of both a spring and magnet. The spring force and/or friction force associated with movement of the LVDT sensing element reduces the accuracy and repeatability of this type system. Other systems may use laser triangulation displacement sensors to measure the deflection of a pressure diaphragm. In addition, other systems may use a ferromagnetic element in the cassette which couples to a magnetic element in the console, which may be coupled with a strain gauge.

Referring now to <FIG>, a system <NUM> for treating an eye E of a patient P generally includes an eye treatment probe handpiece <NUM> coupled with a console <NUM> by a cassette <NUM>. Handpiece <NUM> generally includes a handle for manually manipulating and supporting an insertable probe tip. The probe tip has a distal end which is insertable into the eye, with one or more lumens in the probe tip allowing irrigation fluid to flow from console <NUM> and/or cassette <NUM> into the eye. Aspiration fluid may also be withdrawn through a lumen of the probe tip, with console <NUM> and cassette <NUM> generally including a vacuum aspiration source, a positive displacement aspiration pump, or both to help withdraw and control a flow of surgical fluids into and out of eye E. As the surgical fluids may include biological materials that should not be transferred between patients, cassette <NUM> will often comprise a sterilizable (or alternatively, disposable) structure, with the surgical fluids being transmitted through flexible and/or rigid conduits <NUM> of cassette <NUM> that avoid direct contact in between those fluids and the components of console <NUM>.

When a distal end of the probe tip of handpiece <NUM> is inserted into an eye E, for example, for removal of a lens of a patient P with cataracts, an electrical conductor and/or pneumatic line (not shown) may supply energy from console <NUM> to an ultrasound transmitter of handpiece <NUM>, a cutter mechanism, or the like. Alternatively, handpiece <NUM> may be configured as an irrigation/aspiration (I/A) and/or vitrectomy handpiece. Also, the ultrasonic transmitter may be replaced by other means for emulsifying a lens, such as a high energy laser beam. The ultrasound energy from handpiece <NUM> helps to fragment the tissue of the lens, which can then be drawn into a port of the tip by aspiration flow. So as to balance the volume of material removed by the aspiration flow, an irrigation flow through handpiece <NUM> (or a separate probe structure) may also be provided, with both the aspiration and irrigation flows being controlled by console <NUM>.

To avoid cross-contamination between patients without incurring excessive expenditures for each procedure, cassette <NUM> and its flexible conduits <NUM> may be disposable. However, the flexible conduit or tubing may be disposable, with the cassette body and/or other structures of the cassette being sterilizable. Cassette <NUM> may be configured to interface with reusable components of console <NUM>, including, but not limited to, peristaltic pump rollers, a Venturi or other vacuum source, a controller <NUM>, and/or the like.

Console <NUM> may include controller <NUM>, which may include an embedded microcontroller and/or many of the components common to a personal computer, such as a processor, data bus, a memory, input and/or output devices (including a user interface <NUM> (e.g. touch screen, graphical user interface (GUI), etc.), and the like. Controller <NUM> will often include both hardware and software, with the software typically comprising machine readable code or programming instructions for implementing one, some, or all of the methods described herein. The code may be embodied by a tangible media such as a memory, a magnetic recording media, an optical recording media, or the like. Controller <NUM> may have (or be coupled with) a recording media reader, or the code may be transmitted to controller <NUM> by a network connection such as an internet, an intranet, an ethernet, a wireless network, or the like. Along with programming code, controller <NUM> may include stored data for implementing the methods described herein; and may generate and/or store data that records parameters corresponding to the treatment of one or more patients.

Referring now to <FIG>, a simplified surgical console is illustrated, where a fluid path may be demonstrated under an exemplary embodiment. In this example, an irrigation source <NUM> may be configured as a bottle or bag hanging from an IV pole hanger <NUM>. It is understood by those skilled in the art that, while an integrated IV pole is illustrated, other configurations, utilizing standalone/static IV poles, pressurized infusion sources, and/or other suitable configurations, are contemplated by the present disclosure.

An exemplary irrigation path for fluid may be realized via tubing cassette <NUM> having cassette tubing interface <NUM>, which receives fluid from irrigation source <NUM> via drip chamber <NUM>. Irrigation line 156A and aspiration line <NUM> are coupled to handpiece <NUM>. Irrigation fluid may flow from drip chamber <NUM> through the irrigation tubing into tubing cassette <NUM>. Irrigation fluid may then flow from the tubing cassette through handpiece irrigation line 156A which may be coupled to an irrigation port on handpiece <NUM>. Aspirated fluid may flow from the eye through the handpiece aspiration line <NUM> back to tubing cassette <NUM> and into a waste collection bag <NUM>. A touch screen display <NUM> may be provided to display system operation conditions and parameters, and may include a user interface (e.g., touch screen, keyboard, track ball, mouse, etc. - see controller <NUM> of <FIG>) for entering data and/or instructions to the system of <FIG>.

Referring to <FIG>, an exemplary cassette system showing some of the components and interfaces that may be employed in a phaco system, such as ones illustrated in <FIG>. Handpiece <NUM> may be connected to (or coupled with) the input side of sensor <NUM>, typically by fluid pathways such as fluid pathway <NUM>. Sensor <NUM> may be a pressure, flow, or a vacuum sensor that measures pressure, flow or vacuum, respectively. In a preferred embodiment, sensor <NUM> is a pressure sensor. The output side of sensor <NUM> is connected to valve <NUM> and also connected to pump <NUM> within cassette <NUM> via fluid pathway <NUM>. Valve <NUM> maybe any known valve in the art, e.g. flow selector valve, rotary valve, etc. Valve <NUM> may also be coupled with pump <NUM>. The exemplary embodiment may configure valve <NUM> to interface between handpiece <NUM>, vacuum tank <NUM>, pump <NUM>, which may be a peristaltic pump but may be another type of pump, and collection <NUM>. In this configuration, the system may operate valve <NUM> to connect handpiece <NUM> with vacuum tank <NUM> or with pump <NUM> based on signals received from console <NUM> resulting from the surgeon's input to user interface <NUM> or touch screen display <NUM>. Handpiece <NUM> is connected to pump <NUM> and valve <NUM> provides fluidic connection and disconnection between handpiece <NUM> and tank <NUM>. As discussed herein in greater detail, an aspiration level sensor <NUM> may be communicatively coupled to vacuum tank <NUM>.

The valve <NUM> illustrated in <FIG> may provide a connection between vacuum tank <NUM> and fluid pathway <NUM>. The exemplary embodiment is not limited to one valve and may be realized using two valves each having at least two output ports, possibly connected together to provide the functionality described herein. For example, a pair of two valves may be configured in a daisy chain arrangement, where the output port of a first valve is directly connected to the input port of a second valve. Console <NUM> may operate both valves together to provide three different flow configurations. For example, using two valves, valve one and valve two, valve one may use output port one, which is the supply for valve two. Valve two may connect to one of two ports providing two separate paths. When valve one connects its input port to its second output port rather than the output port that directs flow to the second valve, a third path is provided. It is also envisioned that valve <NUM> may be or comprise one or more pinch valves. The one or more pinch valves may be located along fluid pathway <NUM>, <NUM> and/or <NUM>, or any other fluid pathway as discussed herein.

Console <NUM> may also comprise vacuum pressure center <NUM> which may provide a vacuum through fluid pathway <NUM> to vacuum tank <NUM>. The vacuum provided through fluid pathway <NUM> may be regulated by control module <NUM> based on signals received from aspiration control module <NUM> which may result from the surgeon's input to user interface <NUM> and/or based on other signals received from sensor <NUM>. Aspiration control module <NUM> may also control pump control <NUM> and allow for operation of pump <NUM> for the movement of fluid from both the handpiece <NUM> and the vacuum tank <NUM> to collector <NUM> via pathway <NUM>.

In the configuration shown, vacuum pressure center <NUM> includes a vacuum source <NUM>, such as a venturi pump and an optional control module <NUM> (and valve (not shown)), but other configurations are possible. In this arrangement, vacuum pressure center <NUM> may operate to remove air from the top of vacuum tank <NUM> and deliver the air to atmosphere (not shown). Removal of air from vacuum tank <NUM> in this manner may reduce the pressure within the tank, which may reduce the pressure in the attached fluid pathway <NUM>, to a level less than the pressure within eye <NUM>. A lower reservoir pressure connected through valve <NUM> may cause fluid to move from the eye, thereby providing aspiration.

Thus, while a single valve <NUM> is illustrated in <FIG> associated with aspiration, it is to be understood that this illustration represents a valve arrangement, including one or more valves (e.g. flow selector valve, rotary valve, or the like) performing the functionality described herein, and is not limited to a single device or a single valve. In the exemplary sensor <NUM>, a strain gauge or other suitable component may communicate or signal information to console <NUM> to provide an amount of vacuum sensed in the handpiece fluid pathway <NUM>. Console <NUM> may determine the actual amount of vacuum present based on the communicated information.

In an embodiment, sensor <NUM> monitors fluid pressure in the line, and can be used to determine when fluid flow should be reversed, such as encountering a certain pressure level (e.g. in the presence of an occlusion), and based on values obtained from the sensor <NUM>, the system may control valve <NUM> and the pumps illustrated. It is to be understood that while components presented in <FIG> and other drawings of the present application are not shown connected to other system components, such as console <NUM>, they are in fact connected for the purpose of monitoring and control of the components illustrated.

With respect to sensor <NUM>, emergency conditions such as a dramatic drop or rise in pressure may result in a type of fail-safe operation. The exemplary embodiment employs sensor <NUM> to monitor the flow conditions and provide signals representing flow conditions to the system such as via console <NUM> for the purpose of controlling components shown including but not limited to valve <NUM> and the pumps shown. The fluid pathways or flow segments of surgical cassette system <NUM> may include the fluid connections, for example flexible tubing, between each component represented with solid lines in <FIG>. In an embodiment, the fluid connections may include molded fluid channels.

Handpiece <NUM> may be connected to (or coupled with) the output side of irrigation pressure sensor <NUM>, typically by fluid pathways such as fluid pathway <NUM>. Sensor <NUM> may be a pressure, flow, or a vacuum sensor that measures pressure, flow or vacuum, respectively. In a preferred embodiment, sensor <NUM> is a pressure sensor. The input side of irrigation pressure sensor <NUM> is connected to valve <NUM> within cassette <NUM> via fluid pathway <NUM>. Valve <NUM> may be any known valve in the art, e.g. flow selector valve, rotary valve, etc. The exemplary embodiment may configure valve <NUM> to interface between handpiece <NUM>, irrigation tank <NUM>, pump <NUM>, which may be a peristaltic pump but may be another type of pump, and irrigation fluid source <NUM>. In this configuration, the system may operate valve <NUM> to connect handpiece <NUM> with gravity feed or pressurized irrigation based on signals received from console <NUM> resulting from the surgeon's input to user interface <NUM>.

The valve <NUM> illustrated in <FIG> may provide a connection between irrigation tank <NUM>, irrigation fluid source <NUM>, and fluid pathway <NUM>. The exemplary embodiment is not limited to one valve and may be realized using two valves each having at least two output ports, possibly connected together to provide the functionality described herein. For example, a pair of two valves may be configured in a daisy chain arrangement, where the output port of a first valve is directly connected to the input port of a second valve. Console <NUM> may operate both valves together to provide three different flow configurations. For example, using two valves, valve one and valve two, valve one may use output port one, which is the supply for valve two. Valve two may connect to one of two ports providing two separate paths. When valve one connects its input port to its second output port rather than the output port that directs flow to the second valve, a third path is provided. It is also envisioned that valve <NUM> may be or comprise one or more pinch valves. The one or more pinch valves may be located along fluid pathway <NUM>, <NUM>, <NUM>, <NUM> and/or <NUM>, or any other fluid pathway as discussed herein.

Console <NUM> may also comprise irrigation pressure center <NUM> which may provide a positive pressure through fluid pathway <NUM> to irrigation tank <NUM> using an applied pressure from pressure source <NUM>. The pressure provided through fluid pathway <NUM> may be regulated by control module <NUM> based on signals received from irrigation control module <NUM> which may result from the surgeon's input to user interface <NUM> and/or based on other signals received from sensor <NUM>. Irrigation control module <NUM> may also control pump control <NUM> and allow for operation of pump <NUM> for the movement of fluid from irrigation fluid source <NUM> to collector irrigation tank <NUM> via pathway <NUM>. As discussed herein in greater detail, an irrigation level sensor <NUM> may be communicatively coupled to irrigation tank <NUM>.

While a single valve <NUM> is illustrated in <FIG> associated with irrigation, it is to be understood that this illustration represents a valve arrangement, including one or more valves performing the functionality described herein, and is not limited to a single device or a single valve. In the exemplary irrigation pressure sensor <NUM>, a strain gauge or other suitable component may communicate or signal information to console <NUM> to provide an amount of pressure sensed in the handpiece fluid pathway <NUM>. In another embodiment, depending upon the sensor used, an amount of vacuum or flow may be sensed in the handpiece fluid pathway <NUM> and communicated to console <NUM>. Console <NUM> may determine the actual amount of pressure present based on the communicated information.

<FIG> illustrates an exemplary cassette system showing some of the features which may be employed in a phaco system. The illustrated cassette body <NUM> of cassette <NUM> is shown from the back side (or second side). Cassette body (or cassette fluidics portion) <NUM> may include a series of detents, also referred to as notches or catch surfaces, along its outer edge for receiving at least a portion of a retention device which may be associated with a surgical console to facilitate the retaining of the cassette to console and to at least partially assist in properly seating the cassette in the portion of the console meant to receive the cassette. As illustrated in <FIG>, a cassette may include at least three sets of detents capable of accepting an attachment means provide by the console, such as, for example, upper detents <NUM>, center detents <NUM>, and lower detents <NUM>. As will be described in greater detail below, the detents may be operated on in tandem or in a piecemeal fashion by a retention device of the surgical console.

An exemplary cassette may also include at least one pressurized fluid inlet <NUM> which may be in fluid communication with at least one filter within filter cavity <NUM>. The pressurized fluid, for example, air, may be supplied to the cassette through fluid inlet <NUM> and introduced into pressurized irrigation tank <NUM> and may be in further communication with pressure sensor <NUM>. There may similarly be at least one vacuum inlet <NUM> which may be in fluid communication with at least one filter within filter cavity <NUM>. The vacuum applied through vacuum inlet <NUM> may be in communication with vacuum tank <NUM> and may be in further communication with aspiration channel <NUM> and aspiration channel <NUM>. Each of the pressurized irrigation tank <NUM> and vacuum tank <NUM> may include a level sensing device <NUM> and <NUM>, respectively.

Irrigation fluid may enter the cassette through inlet <NUM> and may enter irrigation channel <NUM>. Irrigation valve <NUM> controls the flow of irrigation fluid and may allow for gravity fed irrigation fluid to be supplied to irrigation outlet <NUM> from irrigation channel <NUM> or pressurized irrigation fluid from pressurized irrigation tank <NUM>. In either instance, and even when irrigation valve <NUM> is in the "off" position relative to both irrigation fluid sources, the amount of pressure associated with the delivery of the irrigation fluid may be measured by irrigation sensor <NUM>. Similarly, aspiration pressure may be measured by the aspiration sensor <NUM> in close proximity to aspiration inlet <NUM>. Aspiration fluid which may enter though aspiration inlet <NUM> may enter aspiration channel <NUM> under pressure produced by at least one peristaltic pump, for example, and may also enter vacuum tank <NUM> under the influence of at least a partial vacuum through valve <NUM>.

As discussed above, cassette <NUM> may also include at least two rotary valves which may enable the cassette to change modes for aspiration and irrigation. The aspiration valve switches between flow mode aspiration and vacuum mode aspiration, with an off position between the two mode positions. The irrigation valve switches between gravity mode irrigation and pressurized irrigation, with an off position in between the two modes. In gravity irrigation mode, the bottle height may control the irrigation pressure. The irrigation valve may be turned such that the flow from the bottle flows through the irrigation valve to the pressure sensor and out to the surgical site through the handpiece. Note that the fluidic channel to the irrigation pump may be sealed off by means of the pump rollers sealing off the peristaltic pump bladder. If the irrigation pump is not running, there will be no flow through the pump.

The system may include a cassette having an internal flow interface as at least partially illustrated in <FIG> illustrates the back side (or second side) of a cassette <NUM>. Such a cassette flow interface may receive fluids, as described in greater detail herein, which may be driven by bladders joined to cassette <NUM> to move fluids through the cassette. Cassette fluidics portion (or cassette body) <NUM> may include a plurality of channels, each with at least one inlet and one outlet. Each channel formed in the cassette fluidics portion <NUM>. For example, channel <NUM> may have outlet <NUM> and outlet <NUM>. Each of outlet <NUM> and <NUM> may include a plurality of openings in which fluids may enter and exit the channel <NUM>. Similarly, channel <NUM> may have at least one inlet <NUM> and inlet <NUM>. When used for transmitting aspiration liquids during cassette engagement, fluids may travel through channel <NUM>, pass through outlets <NUM> and <NUM> and then enter drain channel <NUM> through inlet <NUM> and inlet <NUM>. The outlets from channel <NUM> may be in fluid communication with specific inlets in channel <NUM>. Each inlet and outlet described herein may be shaped to control flow and turbulence of the fluid to be moved through the cassette and may be circular, oval, and/or any shape which may impact fluid flow. As would be appreciated by those skilled in the art, the flow may be reversed and may be used for both irrigation and aspiration functions as desired by the user.

The cassette fluidics portion <NUM> may include channels that allow for simultaneous flow through a variety of inlets and outlets within the same channel network to provide desired flow characteristics, such as control of flow and turbulence. For example, irrigation fluid may enter the cassette <NUM> through channel <NUM> with fluid exiting through outlets <NUM>, <NUM>, and <NUM>. The fluid may enter channel <NUM> through inlets <NUM>, <NUM>, and <NUM>. The outlets from channel <NUM> may be in fluid communication with specific inlets in channel <NUM>. Each inlet and outlet described herein may be shaped to control flow and turbulence of the fluid to be moved through the cassette and may be circular, oval, and/or any shape which may impact fluid flow. As would be appreciated by those skilled in the art, the flow may be reversed and may be used for both irrigation and aspiration functions as desired by the user.

In some embodiments, as illustrated in <FIG>, channel <NUM> may have an inlet from an aspiration tube connection to a cassette, such as connection <NUM> and pressure sensor area <NUM> of <FIG>. The ports <NUM> and <NUM> of <FIG> may be channel <NUM> outlets. In some embodiments, channel <NUM> outlets may also be bladder inlets (i.e., inlet is larger, bypass is smaller). Ports <NUM> may be inlet ports to aspiration bladder section <NUM>. In some embodiments, port <NUM> may be a bypass port to <NUM>. Port <NUM> may be a bladder outlet port from <NUM> and port <NUM> may be the outlet for <NUM>. In some embodiments, channel <NUM> may be an aspiration drain channel with the drain connected to a drain hole <NUM>. In <FIG>, the aspiration bladder rollers may be configured to rotate counter-clockwise.

An irrigation pump, which may have clockwise rotating rollers in <FIG>, may supply fluid from <NUM> into channel <NUM>. Ports <NUM> of bladder section <NUM>, port <NUM> of bladder section <NUM>, and port <NUM> of bladder section <NUM> may be irrigation bladder inlet ports. The irrigation outlet ports may include: port <NUM> (bladder section <NUM>), port <NUM> (bladder section <NUM>) and port <NUM> (bladder section <NUM>), and direct flow from the bladder to the irrigation tank <NUM>, through channel <NUM>.

As illustrated in <FIG>, the front side (or a first side) of a cassette <NUM> is shown. The cassette <NUM> may include an assembly of bladders including at least one aspiration bladder. For example, aspiration bladder may include two sections, such as section <NUM> and section <NUM>. Further, the assembly of bladders may include an irrigation bladder. The irrigation bladder may include three sections, such as section <NUM>, section <NUM>, and section <NUM>.

An assembly of compressible bladders as illustrated in <FIG> on assembly <NUM> may be communicatively coupled to the back of cassette fluidics portion <NUM> and may form a part of cassette <NUM> and may comprise a plurality of bladders which may form at least the top portion of a fluid channel which may interoperate with the fluid channels illustrated in cassette fluidics portion <NUM>. For example, bladder <NUM> may communicatively connect outlet <NUM> and inlet <NUM>. Similarly, bladder <NUM> may communicatively connect outlet <NUM> and inlet <NUM>. Bladder <NUM> may communicatively connect outlet <NUM> and inlet <NUM>, bladder <NUM> may communicatively connect outlet <NUM> and inlet <NUM>, and bladder <NUM> may communicatively connect outlet <NUM> and inlet <NUM>. As illustrated in <FIG>, each of the bladders of assembly <NUM> may form a channel when placed against a planar surface, which channels may be linearly uniform and/or have a variable volume over their respective lengths. In some embodiments, an aspiration bladder may be mounted to a flat surface and an irrigation bladder may be mounted to and make a channel with a conical surface.

As illustrated in <FIG>, each bladder may have at least a minimum uniform channel volume throughout the channel as measured by a measured height formed between the bladder <NUM> and a planar surface represented by line <NUM>. The minimum uniform height may be greater than about <NUM> and may be less than about <NUM> (although each channel may be nonuniform in height and/or radius and may be designed to hold a specific volume of fluid). The minimum uniform radius of a channel may be greater than about <NUM> and may be less than about <NUM>. The minimum radius at position <NUM> may be <NUM>. At least one second radius may be found within the bladder, such as a height of <NUM> at position <NUM>. The at least one second length portion <NUM> may be bordered on each side by first length portion <NUM> and third length portion <NUM>. The change in height between first length portion <NUM> and second length portion <NUM> may occur gradually over the length of first length portion <NUM>, for example, or may occur over a small distance between the two portions sufficient to accommodate an angular rise. For example, such an angular rise may be equivalent to about <NUM> degrees from the top-most portion of first height portion.

As further illustrated in <FIG>, bladder <NUM> may have at least two foot portions <NUM> located in either end of the bladder which may be at least partially in communication with planar surface <NUM>. The top of bladder <NUM> may not follow the same geometry as the inner channel forming portion and may include additional angular elements. For example, first portion <NUM> may include a sloped portion on its proximate end while second portion <NUM> may include at least two sloped portions to accommodate any underlying channel height rise as between first portion <NUM> and third portion <NUM>. The thickness of the bladder may be substantially uniform over most of its length and may be generally concave over the channel forming portion of the bladder.

As further illustrated in <FIG>, cassette <NUM> may comprise cassette body <NUM> which may include on the front face assembly <NUM> and panel <NUM>. Valves <NUM> and <NUM> may be at least partially housed within cassette body <NUM> and in an embodiment, may be at least partially retained in cassette body <NUM> by panel <NUM>. Similarly, pressure sensors <NUM> and <NUM> may be placed in communication with cassette body <NUM> and in an embodiment, may be sealed and/or retained by panel <NUM>. As would be appreciated by those skilled in the art, assembly <NUM> and panel <NUM> may be combined into a single article and may be mechanically and/or chemically fastened to cassette body <NUM>. Tubing assembly <NUM> may include fluid pathways for both irrigation and aspiration, for example, to fluidly couple with a surgical handpiece. Tubing assembly <NUM> may be preferably connected to the bottom of cassette body <NUM> for ease of use but may be joined at any position to cassette body <NUM> as may be considered useful by those skilled in the art.

The back side of cassette body <NUM> may include filters <NUM> and may be sealed by plate <NUM>. As would be appreciated by those skilled in the art, plate <NUM> may be mechanically and/or chemically fastened to cassette body <NUM>, for example. Drain bag <NUM> may be fastened to the exterior of plate <NUM> and may be in fluid communication with one or more fluid conduits within cassette body <NUM>. Fluid from within the cassette body <NUM> may be expelled into fluid bag <NUM>, which may be replaceable and/or itself drained to allow for the expelling of more fluid than could be held in the volume of a single fluid bag <NUM>. Panel <NUM> may also have attached thereto handle <NUM> which may provide for easier handling of cassette <NUM>, for example during insertion and removal from a surgical console. Handle <NUM> may be attached at one or more points on panel <NUM> and may take any number of forms, such as, for example, a ring, square, or other geometric shape.

The bladder assembly may have portions offset from one another and may have portions in multiple planes, for example. One or more of the bladders may include conic portions, cylindrical portions, and wavy portions, for example. A first bladder assembly may be in a first plane and a second bladder assembly may be in a second plane. For example, as illustrated in <FIG> in an isometric view, the console engagement side of cassette <NUM> may include assembly <NUM> which may be shaped to compliantly accept a roller head assembly <NUM> (which is shown in repose from a surgical console). The roller head assembly <NUM> may comprise at least two pump heads, each of which may operate independently from each other. The outermost pump head, pump head <NUM>, for example, may comprise a vertically disposed surface (relative to cassette <NUM>) which may include a plurality of roller assemblies, such as roller assembly <NUM>. An inner pump head, pump head <NUM>, may have a non-linear shape and may, for example, be shaped as a conical frustum, for example. Each pump head may also be spring loaded and or otherwise moveable such that each pump head may have the ability to adjust to the orientation of a mating cassette. Each roller assembly may contain rollers having geometry to minimize slip between a portion of the roller assembly surface and a bladder. For example, a roller may have a conical geometry which allows the roller axis to pass approximately through the center of roller rotation.

<FIG> shows an illustration of the console interface or cassette receptacle for mating a single use cassette with the console. The irrigation and aspiration valves on the single use cassette will center on each of irrigation valve lever <NUM> and aspiration lever valve <NUM>, respectively, once the cassette has been mounted to the console interface <NUM>. As discussed herein, each one of the valve levers may operate responsive to at least one received signal indicative of at least one parameter. Such parameters may include, for example, fluid pressure and fluid volume associated with fluid in the system, whether or not the fluid is in communication with either valve. Similarly, a parameter associated with at least one of a vacuum, a positive pressure and gravity, may also be used.

Each of the irrigation valve and aspiration valve may be in fluid communication with each other. The valves may also be fluidly connected to a line under vacuum and/or to atmosphere. Similarly, the valves may receive one of either pressurized fluid or gravity-fed fluid and may provide a vent for at least one fluidly connected line. Either one of the valves may be partially open to at least one line communicatively connected thereto.

When cassette <NUM> is seated against roller head assembly <NUM>, the roller assemblies of the pump heads may communicatively engage the bladders of assembly <NUM>. For example, as shown in a cut-out view as illustrated in <FIG> and as discussed above, pump head <NUM> may comprise a roller assembly which may further comprise a roller <NUM>, roller body <NUM> and a spring means <NUM>. Roller <NUM> may be movably affixed to roller body <NUM> and may be under a downward force provided by spring means <NUM>, which itself may be affixed to both the pump head <NUM> and roller body <NUM>. Each roller <NUM> may engage a portion of a bladder <NUM> which may be removably affixed to a portion of assembly <NUM> and may engage a bladder with sufficient force as to deform the bladder and cause fluid flow within the channel formed between the bladder <NUM> and the assembly <NUM>. A roller may deform the bladder is a manner sufficient to stop all fluid flow.

Further, as illustrated in <FIG> and <FIG>, a portion of assembly <NUM> may include ports, such as ports <NUM> and <NUM>, which may correspond to inlets and outlets of fluid channels located on the opposite side of assembly <NUM> as discussed above. Shown without the pump head, the portion of assembly <NUM> may comprise multiple bladders, each creating a flow channel <NUM> between the bladder and assembly <NUM>. Although the illustration shows two ports into channel <NUM>, any number of ports may be provided.

As illustrated in the simplified block diagram of <FIG>, a control module associated with a surgical console may control at least one motor which may control the at least two pump heads. As discussed above, each individual pump head may be independently rotated and controlled from a dedicated motor and/or a single motor and may further be responsive to at least one spring mechanism to allow for adjustments in orientation of the pump heads relative to an engaged cassette. Each pump head may be controlled by a dedicated motor placed in line along a shaft which may itself have at least two independent drive shafts. The pump heads may provide peristaltic flow within the engaged cassette and
provide rotation in either a forward or reverse direction. As would be known to those skilled in the art, the control module may receive signals from the pump motor(s) and associated pump encoder(s) responsive to signals received from the surgical console and/or attached devices, such as, for example, a foot pedal and a surgical instrument.

The encoder may comprise an index line output on the motor shaft. There may be two hard stops within the cassette at the following positions: for irrigation at: pressurized irrigation connected and gravity irrigation connected; and for aspiration at: vacuum tank connected and vacuum tank disconnected. There may be a third position on the irrigation valve of irrigation off (no irrigation flow out of the cassette). It is possible to use the index line of the encoder or an absolute position encoder to know the physical orientation of the valve driver head. This may require alignment of the index position to the pump driver head position during manufacturing. A spring in the valve driver head may be used to mate with the rotary valve in the cassette without knowing the orientation of the valve driver head. This would rely on the spring loading to be reliable over wear and would allow the heads to be resistant to any misalignment with a part of the pump head and the cassette.

Similarly, during startup of the console, the motor may spin until the index line is activated, which may be used to place the valve driver head in a specific orientation and zero the encoder counts and motor driver step position. On cassette insertion, the valve stepper motor may spin so that the spring-loaded valve driver head may mate with the cassette. The motor may continue spinning until it hits a hard stop in the cassette. There may be a timeout or certain number of rotations to allow before setting an error that the valve head has not mated. The motor position at the hard stop (reported from either/both the motor driver step position and/or the encoder position) may be saved for returning to that position later during operation. The motor may rotate in the opposite direction to hit the second hard stop. When the motor contacts the hard stop (detect from the encoder and from step loss detection in the motor driver), the encoder and/or step position may be saved for returning to that position later during operation. The angular travel range between hard stops can be checked for an error condition (if there is foreign material or stiction stalling the motor before a hard stop), and the middle irrigation position of off can be set as the middle of the irrigation hard stop range.

Safe state for the system may be when gravity irrigation is connected and aspiration is stopped. The irrigation valve may need to return to the gravity position in a safe state error condition. In an embodiment, for example, the system may require either having the system battery backup always being present and sufficient for the <NUM> seconds of operation or providing enough capacitive hold on the 24V line and an indication that power is going down to move the valve to the intended position if the battery backup is insufficient.

A peristaltic pump consists of elements that pinch and articulate along the closed flexible fluid conduit created, in part, by an aspiration bladder, to force fluid through the conduit. At least two pinchers, particularly pump head rollers, or alternatively wipers, cams, or shoes, sequentially engage and pinch the conduit against a rigid structure and articulate along the conduit length to cause fluid flow. Before the lead pincher disengages the conduit, a subsequent pincher engaged the conduit and articulated along it to ensure continued fluid flow. During disengagement, a momentary disruption of downstream flow may occur as fluid fills the void as the conduit regains its pre-deformed shape. Similarly, upstream flow may be disrupted as the subsequent pincher engages the conduit and fluid is displaced. These disruptions may result in flow and/or pressure pulses both upstream and downstream flow. The present invention may eliminate such pulses upstream of the pump rather than merely mitigating such pulsation.

As may be known to those skilled in the art, one typical method to mitigate such pulsation may involve shaping a rigid structure to control the manner in which the pinchers engage and disengage the conduit to lessen the severity of pulsation by increasing pulse duration. Similarly, larger sections of bladder tubing may be used, as well as varying pump speed to cancel out known pulsations. Pulsation may also be diminished by employing a void in a rigid structure portion such that as three pinchers are simultaneously engaging the flexible conduit, the middle pincher momentarily encounters the rigid structure void thus reducing or eliminating its pinch before fully re-engaging the conduit. The manner in which the pincher encounters the void may mitigate pulsation upstream or downstream of the pump. Further still, other methods may employ a length of semicircular flexible open conduit with capped ends mounted and sealed to a rigid structure, with inlet and outlet flow are provided by ports in the rigid structure under the flexible conduit. In such embodiments, the ends of the fluid volume of these conduits may be tapered to control the manner in which the pinchers engage and disengage the conduit. In embodiments using a semi-circular open conduit, grooves in the rigid structure near the ends of the conduit may provide fluid bypass under the pinched conduit which lessens the severity of and increases the duration of pulses.

In an embodiment of the present invention, a pulseless peristaltic pump may eliminate pulses upstream (inlet side) by providing a flexible conduit of varying volume or displacement in the section of conduit that is engaged by the pinchers. The pulse caused by the subsequent roller engaging the flexible conduit may be absorbed inside of this length of flexible conduit which may result in pulseless flow into the pump. The pulse is essentially cancelled at its source. The present invention is easy to manufacture and does not require additional pump parts. In an embodiment of the present invention, roller tracks may be employed to promote constant pump speed and pulseless flow and decreases the cost and complexity of the pump motivating drive.

In an embodiment of the present invention, at least two separate flexible conduits, created in part by bladders, are arranged in a circular pattern, plumbed together in parallel, and engaged by a pump roller head, as illustrated by <FIG>. Each conduit may consist of a short length of semicircular or similarly shaped flexible open conduit (such as a bladder) that may be mounted and sealed to a cassette so that the cassette and bladder together form a fluid flow path, such as flow channel <NUM> as illustrated in <FIG>. Inlet and outlet flows are provided by ports in the cassette under each end of the bladders.

The bladder sections may be plumbed in parallel inside the cassette while a motor-driven rotating pump head with eight pump roller heads, for example, engages the cassette and bladders. The rollers may be arranged in a circular pattern with the rotational axis of each roller intersecting the pump head rotational axis. The rollers may rotate along a flat and annular path on the front face of the cassette while simultaneously manipulating the bladders. In an aspiration bladder, for example, upstream or inlet pulseless flow may be achieved by shaping the bladder so that the fluid volume of the conduit behind the first roller increases incrementally and exactly to absorb the fluid displaced as the second roller proceeds to pinch the bladders, as illustrated in <FIG>, for example. Thus, the pulse caused by the second roller may be absorbed inside of the bladder and may result in pulseless flow into the pump, which is embodied by a bulge in the bladder.

Bypass ports in the cassette may be placed slightly downstream of the location where the rollers initially seal a bladder against the cassette. These ports may promote pulseless performance by precisely defining pumping handoff from the first roller to the second. Pump speed may be held constant through each pump rotation pump to avoid flow and pressure variation. Two features of the pump promote constant speed by reducing torque pulses caused by interaction between rollers and cassette. Rollers are primarily supported by the front face of the cassette. This mitigates torque variation by providing a smooth, flat, and rigid roller track surface. The bladder wall thickness is tapered at each end of the bladders which effectively provide ramps instead of bumps where the rollers engage and disengage the bladders, as illustrated in <FIG>, for example.

Claim 1:
A system for distributing fluid in a surgical cassette (<NUM>), comprising:
a partially deformable bladder (<NUM>) partially disposed on a rigid surface (<NUM>), wherein the bladder (<NUM>) forms a channel (<NUM>);
a first port (<NUM>) and a second port (<NUM>) in fluid communication with the channel (<NUM>);
wherein at least two pump head rollers (<NUM>) are engaged with the at least partially deformable bladder (<NUM>), wherein a first of the least two pump head rollers (<NUM>) is upstream of the second of the at least two pump head rollers (<NUM>) in a first direction, characterized in that,
along the first direction, the channel comprises a first portion (<NUM>) and a second portion (<NUM>) having a substantially uniform first dimension separated by a third portion (<NUM>) having a second dimension that is larger than the first dimension, such that a fluid volume of the channel (<NUM>) downstream of the first pump head roller (<NUM>) increases incrementally to absorb fluid displaced upstream by the second pump head roller (<NUM>).