Patent Abstract:
A system and method of receiving a cassette to a console of a phacoemulsification system. The system and method may include receiving the cassette in close proximity to a cassette receptacle comprising a receiving surface, sensing variations in at least two variable resistances mounted respectively diagonally about the receiving surface, and comparing the variations as between the at least two variable resistances to assess an attitude of the cassette. The system and method may optionally include clamping the cassette responsively to the comparing step.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of U.S. patent application Ser. No. 13/776,988, filed on Feb. 26, 2013, which claims priority to U.S. provisional application No. 61/612,307, entitled “Surgical Cassette”, filed on Mar. 17, 2012, the entire contents of which are hereby incorporated by reference in their entirety for all purposes as if fully set forth herein. 
    
    
     TECHNICAL FIELD OF THE INVENTION 
     The present invention is generally related to methods, devices, and systems related to apparatuses for controlling surgical fluid flows, particularly during treatment of an eye. 
     BACKGROUND OF THE INVENTION 
     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. This capsular bag is a thin, relatively delicate structure which separates the eye into anterior and posterior chambers. 
     With age, clouding of the lens or cataracts are 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 humour 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 have been used in phacoemulsification and other treatment systems for the eyes, aspiration flow systems can generally be classified in two categories: 1) volumetric-based aspiration flow systems using positive displacement pumps; and 2) vacuum-based aspiration systems using a vacuum source, typically applied to the aspiration flow through an air-liquid interface. These two categories of aspiration flow systems each have unique characteristics that render one more suitable for some procedures than the other, and vice versa. 
     Among positive displacement aspiration systems, peristaltic pumps (which use rotating rollers that press against a flexible tubing to induce flow) are commonly employed. Such pumps provide accurate control over the flow volume. The pressure of the flow, however, is less accurately controlled and the variations in vacuum may result in the feel or traction of the handpiece varying during a procedure. Peristaltic and other displacement pump systems may also be somewhat slow. 
     Vacuum-based aspiration systems provide accurate control over the fluid pressure within the eye, particularly when combined with gravity-fed irrigation systems. While vacuum-based systems can result in excessive fluid flows in some circumstances, they provide advantages, for example, when removing a relatively large quantity of the viscous vitreous humour from the posterior chamber of the eye. However, Venturi pumps and other vacuum-based aspiration flow systems are subject to pressure surges during occlusion of the treatment probe, and such pressure surges may decrease the surgeon&#39;s control over the eye treatment procedure. 
     Different tissues may be aspirated from the anterior chamber of the eye with the two different types of aspiration flow. For example, vacuum-induced aspiration flow may quickly aspirate tissues at a significant distance from a delicate structure of the eye (such as the capsular bag), while tissues that are closer to the capsular bag are aspirated more methodically using displacement-induced flows. 
     Conventionally, fluid aspiration systems include a console and a fluidic cassette mounted on the console. The fluidic cassette is typically changed for each patient and cooperates with the console to provide fluid aspiration. Generally, a single type of cassette is used by a particular console, regardless of whether the procedure will require positive displacement aspiration, vacuum-based aspiration, or both. U.S. Pat. No. 8,070,712; U.S. Published Application 20080114311; and U.S. Published Application 20080114291 provide examples of cassettes currently used in the marketplace, the contents of each are herewith incorporated by reference in their entirety as if set forth herein. 
     Such a cassette is typically physically mated to the afore-discussed console. In providing the physical association between the cassette and the console, at least the aspiration/pumping aspects discussed above must be properly aligned as between the cassette and the console, at least in order to provide proper functionality to the fluid aspiration systems. As such, misalignment may lead to system malfunction, inoperability, or poor performance. However, currently available systems that provide for the alignment of placement and attitude of the cassette onto the console suffer from a variety of issues, including jamming, breakage, and inability to assess a sound alignment and cassette attitude, among others. 
     In light of the above, it would be advantageous to provide improved devices, systems, and methods for eye surgery. 
     SUMMARY OF THE INVENTION 
     The present invention provides a surgical cassette having a front plate, a back plate, and a gasket, wherein at least a portion of the gasket is located between the front plate and the back plate. The gasket may also have one or more valves and a sensor; and the one or more valves and the sensor are accessible through the back plate. The surgical cassette may also have one or more tube retainers configured and dimensioned to guide a portion of a tube into a desired shape. The desired shape may be capable of being used with a peristaltic pump. The tube retainers may be configured and dimensioned to constrain the tube to prevent axial or torsional movement of the tube. 
     The present invention also provides a surgical system having a console, a handpiece, and a cassette, wherein the cassette couples the handpiece with the console. The cassette may have a front plate, a back plate, and a gasket, wherein at least a portion of the gasket is located between the front plate and the back plate. The gasket may have one or more valves and a sensor; and the one or more valves and the sensor may be accessible through the back plate. 
     The present invention also provides a surgical cassette having a front plate having a top portion, a bottom portion, and a front surface, wherein the front plate comprises a handle and thumb shield located between the top portion and the bottom on the front surface. The thumb shield may be located above the handle and comprises a first surface, wherein the first surface comprises a horizontally extending raised surface to constrain a thumb from extending above the top portion. 
     The present invention also provides a surgical cassette having a surface, wherein the surface comprises one or more raised surfaces having a substantially circular shape and wherein the one or more raised surfaces are configured and dimensioned to provide at least one high point for coupling with an engagement mechanism. The engagement mechanism may be selected from the group consisting of a position mechanism and a clamping mechanism. The position mechanism may be selected from the group consisting of a linear actuator, a rotary actuator, and a magnetic coupling. The clamping mechanism may be selected from the group consisting of an electrical actuator, a hydraulic actuator, and pneumatic actuator. 
     The present invention also provides a gasket having a body, wherein the body is deformable and has a front surface and a back surface. The front surface may have one or more raised contours that create one or more channel that are configured and dimensioned to control fluid flow through one or more corresponding channels of a surgical cassette. The back surface may have one or more elevated portions that correspond to the one or more channels of the front surface and act as a valve. The gasket may also have a deformable membrane having an annular surface capable of coupling with a transducer of a surgical console. 
     The present invention also provides a system and method of receiving a cassette to a console of a phacoemulsification system. The system and method may include receiving the cassette into immediate proximity of a cassette receptacle comprising a receiving surface, sensing variations in detectors mounted diagonally about the receiving surface indicative of pressure asserted by the received cassette about the receiving surface, and comparing the variations as between the detectors to assess an attitude of the received cassette. The system and method may optionally include clamping the cassette responsively to the comparing step. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention is best understood with reference to the following detailed description of the invention and the drawings in which: 
         FIG. 1  schematically illustrates an eye treatment system in which a cassette couples an eye treatment probe with an eye treatment console; 
         FIG. 2  illustrates an exemplary surgical cassette having a surgical fluid pathway network for use in the system of  FIG. 1 ; 
         FIG. 3  is a perspective view of an exemplary drain bag port; 
         FIG. 4 a    is a back view of an exemplary surgical cassette; 
         FIG. 4 b    is a perspective back view of an exemplary surgical cassette; 
         FIG. 4 c    is a perspective back view of an exemplary surgical cassette; 
         FIG. 5 a    is an exploded view of an exemplary surgical cassette; 
         FIG. 5 b    is a top view of the back of the front plate of an exemplary surgical cassette; 
         FIG. 6  is an exploded view of an exemplary surgical cassette; 
         FIG. 7  is an exploded view of an exemplary surgical cassette; 
         FIG. 8  is a perspective view of the front of an exemplary surgical cassette; 
         FIG. 9 a    is a perspective view of the front of an exemplary surgical cassette with a drain bag; 
         FIG. 9 b    is a perspective view of the back of an exemplary surgical cassette with a drain bag and flexible conduit; 
         FIG. 10 a    is a perspective view of the back of an exemplary gasket; 
         FIG. 10 b    is a perspective view of the front of an exemplary gasket; 
         FIG. 11  is a top view of an exemplary surgical console; 
         FIG. 11 a    is a perspective view of the front of an exemplary surgical console; 
         FIG. 12  is a top view of an exemplary surgical console with a surgical cassette coupled therewith; 
         FIG. 13  is a perspective view of an exemplary surgical consol with a surgical cassette coupled therewith; 
         FIG. 14 a    is a cross-sectional view of an exemplary surgical cassette clamping mechanism; 
         FIG. 14 b    detailed view of the exemplary surgical cassette interface (part A) as illustrated in  FIG. 14   a;    
         FIG. 15 a    is a perspective view of an exemplary surgical cassette clamp; 
         FIG. 15 b    is a perspective view of an exemplary surgical cassette clamp; 
         FIG. 16 a    is a cross-sectional view of an exemplary surgical cassette detection mechanism; 
         FIG. 16 b    is a cross-sectional view of an exemplary surgical cassette detection mechanism; 
         FIG. 17 a    is a cross-section view of an exemplary peristaltic pump roller assembly; 
         FIG. 17 b    is a detailed view of the exemplary peristaltic pump roller assembly (part B) as illustrated in  FIG. 17   a;    
         FIG. 18  is a cross-sectional view of an exemplary surgical cassette illustrating the peristaltic pump tube and peristaltic pump profile; 
         FIG. 19  is a schematic illustration of an exemplary spring-loaded depressable shaft potentiometer; and 
         FIGS. 20 a  and 20 b    are rear and front views, respectively, of cross sectional views of a console&#39;s cassette receiver including potentiometers. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Reference will now be made in detail to embodiments of the invention, examples of which are illustrated in the accompanying drawings. While the invention will be described in conjunction with the embodiments, it will be understood that they are not intended to limit the invention to those embodiments. On the contrary, the invention is intended to cover alternatives, modifications, and equivalents, which may be included within the spirit and scope of the invention as defined by the appended claims. 
     Referring to  FIG. 1 , a system  10  for treating an eye E of a patient P generally includes an eye treatment probe handpiece  12  coupled to a console  14  by a cassette  100  mounted on the console. Handpiece  12  may include 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 the console  14  and/or cassette  100  into the eye. Aspiration fluid may also be withdrawn through a lumen of the probe tip, with the console  14  and cassette  100  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  100  will often comprise a disposable (or alternatively, sterilizable) structure, with the surgical fluids being transmitted through flexible conduits  18  of the cassette that avoid direct contact in between those fluids and the components of console  14 . 
     When a distal end of the probe tip of handpiece  12  is inserted into an eye E, for example, for removal of a lens of a patient with cataracts, an electrical conductor and/or pneumatic line (not shown) may supply energy from console  14  to an ultrasound transmitter of the handpiece, a cutter mechanism, or the like. Alternatively, the handpiece  12  may be configured as an irrigation/aspiration (I/A) 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  12  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  12  (or a separate probe structure) may also be provided, with both the aspiration and irrigations flows being controlled by console  14 . 
     So as to avoid cross-contamination between patients without incurring excessive expenditures for each procedure, cassette  100  and its flexible conduit  18  may be disposable. Alternatively, the flexible conduit or tubing may be disposable, with the cassette body and/or other structures of the cassette being sterilizable. Regardless, the disposable components of the cassette are typically configured for use with a single patient, and may not be suitable for sterilization. The cassette will interface with reusable (and often quite expensive) components of console  14 , which may include one or more peristaltic pump rollers, a Venturi or other vacuum source, a controller  40 , and the like. 
     Controller  40  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 touch screen user interface  42 ), and the like. Controller  40  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  40  may have (or be coupled to) a recording media reader, or the code may be transmitted to controller  40  by a network connection such as an internet, an intranet, an Ethernet, a wireless network, or the like. Along with programming code, controller  40  may include stored data for implementing the methods described herein, and may generate and/or store data that records perimeters with corresponding to the treatment of one or more patients. Many components of console  14  may be found in or modified from known commercial phacoemulsification systems from Abbott Medical Optics Inc. of Santa Ana, Calif.; Alcon Manufacturing, Ltd. of Ft. Worth, Tex.; Bausch and Lomb of Rochester, N.Y.; and other suppliers. 
       FIG. 2  illustrates a surgical cassette of the present invention, including components of surgical cassette  100 . Surgical cassette  100  is an assembly of fluid pathways and connected tubing configured to manage one or more of the following: fluid inflow, fluid outflow, fluid vacuum level, and fluid pressure in a patient&#39;s eye E when coupled with console  14 . Surgical cassette  100  may include grip loop handle  101 , which provides a sterile means for holding and positioning surgical cassette  100  under finger grip control. In an embodiment, grip loop handle  101  is designed for an index finger to pass completely thru the loop of the handle. The grip loop handle  101  may also be designed for the pad of the thumb to rest on outer top surface of grip loop handle  101 . 
     In an embodiment, surgical cassette  100  may include a thumb shield  102 . As illustrated in  FIG. 2 , thumb shield  102  may have a raised border above grip loop handle  101 , which is configured and dimensioned to surround a sterile gloved thumb to reduce potential for contact with non-sterile surfaces during insertion of surgical cassette  100  into console. Thumb shield  102  may have one or more surface elements. For example, thumb shield  102  may have one or more generally horizontally extending raised surfaces to constrain the tip of the thumb from extending beyond the upper shielded coverage of the frame of surgical cassette  100 . Thumb shield  102  may have in the alternative or in addition to the one or more horizontally extending raised surface, one or more generally vertically extending raised surfaces to constrain the side of the thumb from slipping sideways (left or right) beyond the coverage of the thumb shield  102  constraining surface(s). 
     In an embodiment, surgical cassette  100  may include drain bag port  103 . As illustrated in  FIG. 2 , drain bag port  103  is an axially extending cylindrical port with a central opening to enable the transfer of fluid from the inside of the surgical cassette  100  manifold to an externally attached collection reservoir such as drain bag or collection vessel  140  (see  FIGS. 9 a  and 9 b   ). In an embodiment as illustrated in  FIG. 3 , drain bag port  103  may have one or more recessed notches  103   a  in the end face of drain bag port  103  to provide one or more gaps for fluid to flow into an externally attached bag. Such a feature helps to minimize the potential for the bag surface to obstruct fluid outflow through the port. Inside surface feature  103   b  may be configured to accept a male slip luer fitting to support the connection to external tubing sets. 
     As illustrated in  FIG. 2 , surgical cassette  100  may include a drain bag hook  104 . Drain bag hook  104  is a mechanical feature extending outward from the surface of surgical cassette  104  and is configured to interface with a corresponding slot feature in the drain bag  140  (see  FIG. 9 a   ) to support the weight of the drain bag as it collects fluid. 
     Surgical cassette  100  may also include one or more clamping domes  106 . As illustrated in  FIG. 2 , clamping domes  106  may be a raised pattern of spherical domed surfaces with a single high-point to provide low friction wiping contact surfaces during loading and concentrate axial clamping forces in specific zones after loading surgical cassette  100  with console  14 . It is also envisioned that the one or more clamping domes  106  may be of any shape or size suitable for its function or desired aesthetic look and feel. 
     In an embodiment, surgical cassette  100  may include peristaltic pump tube  107 .  FIG. 4 a    shows the backside of surgical cassette and peristaltic pump tube  107 . Peristaltic pump tube  107  may be an elastomeric length of tubing that is configured to generate positive displacement of fluid flow in the direction of pump roller (not shown) when a portion of the tubing is compressed between the peristaltic pump rollers of console  14  and the backing plate pump profile  108  of the surgical cassette  100 . It is also envisioned that any type of flow-based pump and corresponding components may be used with surgical cassette  100 . In an embodiment, backing plate pump profile  108  may be comprised of contoured surfaces formed on the inside of cassette frame/front plate  100   a  to provide a compressing tubing while creating peristaltic pumping flow. 
     As illustrated in  FIGS. 4 a , 4 b , and 4 c   , surgical cassette  100  may have axial mating plane surfaces  105 . Axial mating plane surfaces  105  are outer border faces of cassette frame/front plate  100   a  that form a surface mating with console  14  within cassette receiver  123  after loading. 
     In an embodiment, surgical cassette  100  may also include one or more peristaltic tube form retainers  109 . (See  FIGS. 4 a , 4 b , 4 c   ,  5 ,  6 , and  18 ) Clamping surfaces formed between the cassette frame/front plate  100   a  and backing plate  100   b  are configured to axially retain the tubing to maintain consistency of tubing stretch and provide centering of tubing within peristaltic pump profile  108 . Form retainers  109  may comprise mating sections  109   a  of cassette frame front plate  100   a . Form retainers  109  are configured and dimensioned to shape peristaltic pump tube  107  and in the embodiment illustrated in the figures, to guide peristaltic pump tube  107  into an approximately 180 degree turn on each end of tube  107 . 
     In an embodiment as illustrated in  FIGS. 4 a , 4 b , and 4 c   , backing plate  100   b  may be recessed within cassette frame/front plate  100   a  such that when surgical cassette  100  is inserted into console  14 , backing plate  100   b  does not touch the cassette receiver  123 . In the alternative, backing plate  100   b  may be configured and dimensioned to touch cassette receiver  123 . 
     Referring to  FIGS. 5 a , 5 b   ,  6 ,  7 , and  18 , surgical cassette  100  may also include one or more pump tube interface ports  110 . Pump tube interface ports  110  are inlet and outlet transition ports to transition fluid flow from internal molded manifold fluid flow channels  111  to peristaltic pump tube  107 . In an embodiment, surgical cassette  100  may also include one or more manifold fluid flow channels  111 . Manifold fluid flow channels  111  are fluid flow pathways formed as raised surfaces allowing fluid to flow in internal channels between the raised surfaces and outer perimeter sealing border of gasket  120  to retain fluid within the manifold fluid flow channels  111  under positive pressure and vacuum conditions. Manifold fluid flow channels  111  may comprise irrigation flow channel  111   a , which is a pathway with an inlet tubing port from balance salt solution (BSS) irrigation bottle metered by valves to one or more, preferably two outlet ports: (1) irrigation tubing outlet port  118  connected to an external surgical handpiece  12  flowing fluid to the eye, which may be metered or controlled by irrigation valve  113 ; and (2) venting line  111   b  providing BSS irrigation fluid into an aspiration line of flexible conduits  18  which may be metered or controlled by vent valve  114 . 
     Manifold fluid flow channels  111  may also have aspiration flow channel  111   b . Aspiration flow channel  111   b  may include a pressure/vacuum sensor element  111   c , a pumping outlet port  111   d , and two inlet ports comprising aspiration fluid inflow from tubing line connected to external surgical handpiece  12  and venting fluid inflow from BSS irrigation bottle, which may be metered by vent valve  114 . Manifold fluid flow channels  111  may also comprise vent flow channel  111   c . Vent flow channel  111   c  is a pathway configured to provide BSS irrigation fluid into the aspiration line, which may be metered by vent valve  114  to reduce vacuum level in the aspiration line following handpiece  12  tip obstruction or occlusion. Manifold fluid flow channels  111  may also have manifold channel sealing surfaces  112 , which comprise the top surface or portion thereof of the channels  111 . 
     Referring to  FIGS. 4 a , 4 b , 4 c   ,  5 , and  6 , surgical cassette  100  may include irrigation valve  113 , which in an embodiment may have a dome-like shape. Irrigation valve  113  may be an elastomeric deformable surface which allows irrigation flow from a BSS bottle to external surgical handpiece  12  when uncompressed and shuts off flow when deformed inwards towards manifold fluid flow channels  111 . Surgical cassette  100  may also include vent valve  114 , which in an embodiment may have a dome-like shape. Vent valve  114  may be an elastomeric deformable surface which allows irrigation flow from the BSS bottle through the aspiration line that coupled with the external surgical handpiece  12  resulting in vacuum level reduction when uncompressed and shuts off flow when deformed inwards towards manifold fluid flow channels  111 . The level of fluid flow may be controlled based upon the level of compression of valves ( 113  and  114 )—from full flow to intermediate flow to no flow. 
     In an embodiment illustrated in  FIGS. 5 a , 5 b   , and  6 , surgical cassette  100  may have irrigation valve control surface  115 . Irrigation valve control surface  115  may be a raised sealing surface in manifold fluid flow channels  111  that provides irrigation fluid flow reduction or shutoff from the BSS irrigation bottle to an irrigation inlet fitting of surgical handpiece  12  when irrigation valve control dome is compressed or activated. Surgical handpiece  100  may also include vent valve control surface  116 . Vent valve control surface  116  may be a raised sealing surface in manifold fluid flow channels  111  that provides shutoff of venting of irrigation fluid flow from the BSS irrigation bottle to an aspiration fitting of surgical handpiece  12  when vent valve  114  is compressed or activated. 
     In an embodiment illustrated in  FIG. 8 , surgical cassette  100  may include irrigation inlet tubing port  117 , irrigation outlet tubing port  118 , and aspiration outlet tubing port  119 . Irrigation inlet tubing port  117  may be a connection port for tubing extending to the BSS irrigation bottle to deliver irrigation fluid to manifold fluid flow channels  111 . Irrigation outlet tubing port  118  may be a connection port for tubing extending to the surgical handpiece  12  irrigation fitting to deliver irrigation fluid from manifold fluid flow channels  111  to patient&#39;s eye E. Aspiration outlet tubing port  119  may be a connection port for tubing extending to the surgical handpiece  12  aspiration fitting for removing fluid from a patient&#39;s eye E by means of a pump, such as a flow-based pump, preferably a peristaltic pump comprising the peristaltic pump tube  107 . In an embodiment, surgical cassette  100  may also include or in the alternative of drain bag port  103 , optional drain port  103   c , which may be connected to an external tubing line or reservoir. In an embodiment, drain port  103   c  may be closed by a plug or similar device known in the art. 
     Surgical cassette  100  may include gasket  120  as illustrated in  FIGS. 10 a  and 10 b   , which may be an integrated elastomeric fluid channel sealing gasket. Gasket  120  may include a vacuum/pressure sensor diaphragm  120   a , irrigation valve control dome  113 , and vent valve control dome  113 . Gasket  120  may also include fluid channel sealing surfaces  120   b . Vacuum/pressure sensor diaphragm  120   a  may be a sealed flexible annular membrane with a central magnetic coupling disk which deforms: (1) proportionally outwards under fluid pressure conditions compressing a magnetically-coupled force displacement transducer of console  14  allowing for non-fluid contact measurement of fluid pressure level inside the aspiration fluid pathways of surgical cassette  100 ; and (2) proportionally inwards under fluid vacuum conditions extending the magnetically-coupled force displacement transducer of console  14  allowing for non-fluid contact measurement of fluid vacuum level inside the aspiration fluid pathways of surgical cassette  100 . In an embodiment, gasket  120  may have one or more fluid channel sealing surfaces  120   d , which may be a raised lip portion of the gasket  120 . In the embodiment shown in  FIG. 10 a   , two such sealing surfaces  120   b  are illustrated. 
     In an embodiment, gasket  120  may be molded onto the backing plate  100   b  by co-molding or any other process known in the art. Co-molding the gasket  120  and backing plate  100   b  result in a combination of elastomeric features of gasket  120  and rigid features of backing plate  100   b.    
     In an embodiment, surgical cassette  100  may also include pressure/vacuum sensor concentric alignment ring  121  as illustrated in  FIGS. 4 a , 4 b , 4 c , and 5 a   . Alignment ring  121  may include a pattern of a radially oriented rib features defining a circular arc of a specific diameter and location to provide for concentric alignment between the center of the magnetically-coupled force displacement transducer  131  of console  14  and the center of vacuum/pressure diaphragm  120   a  of surgical cassette  100 . The pattern may comprise one or more radially oriented rib features, preferably a minimum of three radially oriented rib features. 
     In  FIGS. 11, 11   a ,  12  and  13 , fluidics module  122  is illustrated according to an embodiment of the present invention. Fluidics module  122  comprises an assembly of components mounted in console  14  for interfacing with surgical cassette  100 . Fluidics module  122  may have one or more of the components described herein. Fluidics module  122  may have cassette receiver  123 , cassette pre-load detection pin  124 , and pre-load detection switch  125  (shown in  FIG. 16 a   ). Cassette receiver  123  may be a section of fluidics module  122  defining an engagement area for loading and aligning surgical cassette  100  in its intended position relative to various components of fluidics module  122 . Cassette receiver  123  may have tapered lead-in pre-alignment surfaces  123   a , which may include outside vertical and horizontal border surfaces of cassette receiver  123  that may be tapered towards the center of the opening of cassette receiver  123  to guide surgical cassette  100  into a substantially centered position during off-angle insertion. Cassette receiver  123  may also have axial interface surface  123   b , which may include planar engagement surfaces where cassette frame/front plate  100   a  bottoms out when fully constrained by rotary clamps  126 ,  127 . 
     Cassette pre-load detection pin  124  may be a spring-loaded pin displaced rearwards when surgical cassette  100  is initially inserted with an end or side surface triggering a switch and initiating closure of rotary clamps  126 ,  127 . Pre-load detection switch  125  may be a switch component that changes electrical output state when cassette pre-load detection pin  124  has been displaced to a specific axial position indicating surgical cassette  100  is in an appropriate position for loading engagement by rotary clamps  126 ,  127  (see  FIGS. 15 a  and 15 b   ). In an optional embodiment, as shown in  FIG. 16 b   , a second detection switch  142  may be located next to or behind detection switch  125  to monitor the position of pre-load detection pin  124  to verify that surgical cassette  100  reaches its intended interface position at the completion of the cassette clamping mechanism closure. 
     Left rotary clamp  126  may be a rotating clamping component configured with specific surfaces to clamp surgical cassette  100  when rotated in a counter-clockwise direction as viewed from the top T and specific ejection surfaces to disengage surgical cassette  100  when rotated in the opposite direction. Right rotary clamp  127  may be a rotating clamping component configured with specific surfaces to clamp surgical cassette  100  when rotated in a clockwise direction as viewed from top T and specific ejection surfaces to disengage surgical cassette  100  when rotated in the opposite direction. 
     In an embodiment, fluidics module  122  may have a left clamping motor actuator  128  and a right clamping motor actuator  129 . Left clamping motor actuator  128  may be a reversible rotary actuator powered by electricity, pneumatics, hydraulics, or any other means know in the art, that controls the rotational position of the left rotary clamp  126  to alternately load and eject surgical cassette  100 . Right clamping motor actuator  129  may be a reversible rotary actuator powered by electricity, pneumatics, hydraulics, or any other means know in the art, that controls the rotational position of the right rotary clamp  127  to alternately load and eject surgical cassette  100 . The actuation of the motor actuators  128  and  129  may be simultaneously or individually controlled. 
     In an embodiment, fluidics module  122  may have a pump roller assembly  130 . Pump roller assembly may have a configuration of multiple roller elements in a circular or substantially circular pattern which produce peristaltic flow-based fluid transport when rotated against compressed fluid-filled peristaltic pump tube  107 . 
     In an embodiment, fluidics module  122  may have a force displacement transducer  131 . Force displacement transducer  131  may operate by means of a magnetic coupling, such that fluid vacuum inside manifold fluid flow channels  111  causes deformation inwards of vacuum/pressure sensor diaphragm  120   a  in surgical cassette  100 , which axially extends force displacement transducer  131  resulting in a change of an electrical output signal in proportion to a vacuum level. Positive fluid pressure in manifold fluid flow channels  111  results in an outward extension of vacuum/pressure sensor diaphragm  120   a  and compression of the force displacement transducer  131 . 
     In an embodiment, fluidics module  122  may have irrigation valve plunger  132  and vent valve plunger  133 . Irrigation valve plunger  132  may have an axial extension of the plunger that compresses irrigation valve  113  of surgical cassette  100  resulting in a decrease or shutoff of irrigation flow to external irrigation tubing line of flexible conduit  18 . Irrigation valve plunger  132  may also operate by a spring-loaded retraction of the plunger to allow varying levels of irrigation flow. Vent valve plunger  133  may have an axial extension of the plunger that compresses vent valve  114  of surgical cassette  100  resulting in a decrease or shutoff of irrigation venting flow to external aspiration tubing line of flexible conduit  18 . Vent valve plunger  133  may also operate by a spring-loaded retraction of the plunger to allow irrigation pressure fluid flow to vent vacuum level in aspiration tubing line of flexible conduit  18 . 
     In an embodiment, fluidics module  122  may have one or more of the following components: peristaltic drive motor actuator  134 , peristaltic pump motor drive pulley  135 , peristaltic drive belt  136 , peristaltic roller driven pulley  137 , and pump roller guide bearings  138 . Peristaltic drive motor actuator  134  may be a reversible rotary actuator powered by electricity, pneumatics, hydraulics, or any other means known in the art that controls the rotational position of the peristaltic pump roller assembly  130 . Peristaltic pump motor drive pulley  135  may have a pulley wheel connected to the rotary drive shaft of peristaltic drive motor actuator  134  to provide a mating interface for peristaltic drive belt  136  when peristaltic drive motor actuator  134  is oriented on an offset parallel axis to peristaltic pump roller assembly  130  for reducing overall height of fluidics module  122 . Peristaltic roller driven pulley  137  may have a pulley wheel connected to rotary shaft peristaltic pump roller assembly  130 . Peristaltic drive belt  136  may be a belt connecting peristaltic pump motor drive pulley  135  to peristaltic roller driven pulley  137  to transfer rotation of the pump drive motor shaft to the peristaltic pump roller assembly  130 . 
     Pump roller guide bearings  138  may have at least one low friction bearing placed in concentric alignment with peristaltic pump roller assembly  130  to guide shaft rotation of peristaltic pump roller assembly  130 . Pump roller guide bearings  138  may compensate for off-axis forces from compression of peristaltic pump tube  107  by peristaltic pump roller assembly  130  and peristaltic drive belt  136  tension between pulleys  135  and  137 . 
     In an embodiment, fluidics module  122  may have rotary pump roller position encoder  139 . Rotary pump roller position encoder may have an electronic output signal indicating rotary position of peristaltic pump roller assembly  130 , which may be used to derive and confirm intended rotational speed during peristaltic pumping. Rotary pump roller position encoder  139  may also be used to provide controlled rotary position changes for the following purposes: increase or decrease pressure level in fluid line by a target amount by transferring a predetermined volume of fluid into or out of the fluid line faster than closed-loop pressure monitoring allows based on an algorithm assuming a known overall system volume; and/or increase or decrease vacuum level in fluid line by a target amount by transferring a predetermined volume of fluid into or out of fluid line faster than closed-loop vacuum monitoring allows based on an algorithm assuming a known overall system volume. 
     Operation of Surgical Cassette and Console 
     The following describes exemplary embodiments of operating surgical cassette  100  and console  14  according to the present invention. In an embodiment, a surgical technician grasps surgical cassette  100  by placing an index finger through the opening of grip loop handle  101  and gripping handle  101  with thumb pressure on thumb shield  102  (outer top surface of handle). The surgical technician&#39;s hand can remain sterile while tubing lines are handed off to supporting non-sterile staff to make connections to the non-sterile BSS irrigation bottle. With the surgical technician&#39;s thumb being shielded from inadvertent contact with non-sterile outer surfaces of console  14  by means of thumb shield  102 , surgical cassette  100  may be directly inserted into cassette receiver  123  of fluidics module  122  with centering guidance provided by tapered outer surfaces  123   a . The direct axial insertion of surgical cassette  100  into cassette receiver  123  of fluidics module  122  results in axial mating plane surfaces  105  contacting ejection surfaces  126   b  and  127   b  of left and right rotary clamps  126 , 127 . (See  FIGS. 14 a , 14 b , 15 a , and 15 b   ). 
     Approximately synchronized with contacting ejection surfaces  126   b  and  127   b  of rotary clamps  126 ,  127 , cassette pre-load detection pin  124  is compressed triggering a switch signal to be sent from cassette pre-load detection switch  125  to the control means of console  14 . Triggering of cassette pre-load detection switch  125 , triggers rotation of clamping motor actuators  128 ,  129  and contact between loading clamp surfaces  126   a ,  127   a  of rotary clamps  126 ,  127  and clamping domes  106  on cassette frame/front plate  100   a . Clamping motor actuators  128 ,  129  will continue to rotate until axial mating plane surfaces  105  of cassette frame/front plate  100   a  are compressed fully flat and parallel to mounting reference surfaces of fluidic module  122 . 
     Surgical cassette  100  is guided into horizontal and vertical preferred alignment by concentric alignment of ribs  121  of pressure/vacuum sensor diaphragm  120   a  of surgical cassette  100  with outer ring surface  131   a  (see  FIG. 11 a   ) of force displacement transducer  131 . See  FIG. 11 a   . After tubing connections are made to external accessories (e.g., handpiece  12  with attached phaco needle tip and irrigation sleeve (not shown)), surgical staff initiates a fluid priming of tubing lines and internal cassette fluid pathways (i.e. manifold fluid flow channels  111 ) with irrigation fluid delivered from an irrigation source (e.g. BSS bottle) 
     Console  14  may verify one or more of the following: proper tubing connections, fluid line sealing, and fluid control operation during the priming procedure by generating flow through aspiration pathways of manifold fluid flow channels  111  by rotating peristaltic pump roller assembly  130  against outer surface of peristaltic pump tube  107  in compression against peristaltic pump profile  108  of backing plate  100   b.    
     Desired and/or appropriate pressure and vacuum levels are verified by means of the magnetically-coupled pressure/vacuum sensor diaphragm  120  pulling outwards on force displacement transducer  131  in proportion to an actual vacuum level and pushing inwards in proportion to actual pressure levels. 
     Fluid flow may be metered on and off or varied by means of extending and retracting irrigation and vent valve plungers  132 ,  133 , which shutoff or vary fluid flow when extended to compress sealing surfaces of irrigation valve  113  and vent valve  114  against irrigation and vent valve surfaces  115 ,  116 . 
     A surgical user may control the outflow rate of fluid from externally attached tubing accessories (e.g., handpiece  12  with attached phaco tip and irrigation sleeve (not shown)) by selecting desired aspiration pump flow rate which is converted by one or more control algorithms of console  14  into speed of rotation of peristaltic pump roller assembly  130 . 
     According to an embodiment, to enable reduced overall height of fluidics module  122 , peristaltic drive motor actuator  134  may be configured as a parallel axis drive mechanism such as the belt drive and pulley mechanism described herein. In another embodiment, peristaltic drive motor actuator  134  may be oriented such that the drive shaft is perpendicular to the peristaltic pump roller assembly  130  using one or more gears to couple the peristaltic drive motor actuator  134  with the peristaltic pump roller assembly  130 . This in turn would also enable a reduction of overall height of fluidics module  122 . 
     Referring to  FIGS. 16 a , 16 b , 17 a , and 17 b   , in another embodiment, using a non-axial drive connection between peristaltic drive motor actuator  134  and peristaltic pump roller assembly  130 , a rotary pump roller position encoder  139 , which may be any type of indicator known in the art, may be mounted onto the rotating shaft of peristaltic pump roller assembly  130  to detect slippage or asynchronous rotation of peristaltic drive motor actuator  134  with respect to peristaltic pump roller assembly  130 . Since peristaltic pumping is generated in direct proportion to peristaltic pump roller assembly  130  to rotational speed of peristaltic drive motor actuator  134  during slippage conditions, placement of rotary pump roller position encoder  139  onto peristaltic pump roller assembly  130  provides increased accuracy and reliability of intended operation. 
     When the surgical procedure is completed, surgical staff initiate ejection of surgical cassette  100  from fluidics module  122  by activating ejection switch  141  (see  FIG. 11 a   ) which signals the clamp motor actuators  128 ,  129  to reverse rotation and disengage axial mating plane surfaces  105  of surgical cassette  100  from axial interface surface  123   b  of fluidics module  122  by a controlled distance. 
     In an embodiment, the final ejected position of surgical cassette  100  results in surgical cassette  100  still being retained on its outer border edges within the lead-in portion  123   a  (see  FIGS. 11 and 11   a ) of cassette receiver  123  to prevent surgical cassette  100  having internal surgical waste fluid from falling onto the floor. 
     In yet another embodiment, a potentiometer-based cassette attitude, alignment, and load complete detection “switch” may be provided. More particularly, this potentiometer-based switch allows for predisposition of the planar attitude and alignment of a cassette  100  presented to the cassette receiver  123  of the fluidics module  122 . In short, only a cassette  100  presented in an acceptable attitudinal angular range, and with the proper alignment, will allow the fluidics module  122  to receive the cassette  100  and operate any of the cassette clamping or seizing mechanisms discussed herein. Consequently, the cassette  100  may not be presented in a manner that would cause the clamping mechanism to jam, or that would cause the cassette  100  to be misaligned with the cassette receiver  123 . In prior systems and methods, the planar orientation and alignment of the cassette was not adequately accounted for, and consequently the cassette could be improperly forced, or jammed, into place. In contrast, in the exemplary system and method provided herein, the aforementioned mechanical potentiometer-based micro-switch is provided, whereby improved reliability and refined control is available to prevent forcing, jamming, misalignment, or other malfunction. 
       FIG. 19  is a schematic illustration of an exemplary potentiometer  202  for use in the instant embodiments. Those skilled in the art will appreciate, in light of the disclosure herein, that the potentiometer  202  may be or include any means of providing a detector for variations in electrical resistance, and that the variations in electrical resistance provided may be stepped, i.e., may have discrete available values, or may be continuous. Further, the detector may be of any form suitable to provide variations in electrical resistance responsive to pressure thereupon, such as the aforementioned potentiometer, a Wheatstone bridge, a resistive divider, or the like. Additionally, the detector may be actuated by any known mechanism, including but not limited to the linearly displaced shaft  204  discussed herein. 
     The exemplary potentiometer shown in  FIG. 19  includes a spring loaded, self-guided plunger shaft  204  and associated housing  206 , which shaft  204  may pass through, or which shaft  204  may connect to a rod  208  that passes through, a mounting body  210 . The axis of the shaft  204  may run parallel to the length of the housing  206 , with the spring (not shown) internal to the housing and proximate to a closed base thereof, wherein an end of the shaft  204  fully contained within the housing  206  may rest upon the spring. The rod  208  may comprise a machined adaptor that is pressed on, glued on, welded on, or threaded on to the shaft  204  of the potentiometer. If provided, the rod  208  must be mounted reasonably accurately to the shaft  204 , to thus avoid misrepresentation of the attitude or alignment of the cassette  100  as discussed further below. Additionally, the spring loaded nature of the potentiometer shaft  204  and rod  208  (if so equipped) provides a controlled resistance to an operator inserting the cassette  100  progressively through the plane at the mouth of the cassette receiver  123 , thereby helping to limit erratic insertion attempts. 
     As in a typical linear potentiometer, when the shaft  204  is depressed, a modification to the resistance provided by the potentiometer  202  is effected. Accordingly, the linear position of the axial shaft  204  dictates a particular resistance of the potentiometer. Thereby, the resistance of the illustrative potentiometer  202  is also indicative of the position of that which is depressing the shaft  204  (or rod  208 )—which, in this illustration, may be either the cassette  100  or the fluidics module  122  for receiving the cassette  100 , depending upon whether the potentiometer  202  is physically associated with the fluidics module  122  or the cassette  100 , respectively. That is, a linear potentiometer  202  may be employed on the fluidics module  122  to indicate the relative position of the cassette  100  being mated to the fluidics module  122 , or may be mounted on the cassette  100  to indicate the relative position of the fluidics module  122  with respect thereto. 
     In order to allow for physical association of the potentiometer  202  with either the cassette  100  or the fluidics module  122 , the potentiometer  202  may include the aforementioned mounting body  210 . The axial shaft  204  of the potentiometer  202  may extend through a hole in the mounting body  210 , or may mate with the rod  208  that then extends through the hole in the mounting body  210 . The rod  208  may effectively extend the axial shaft  204  of the potentiometer  202  to allow for detection of the extent of depression of the axial shaft  204  as dictated by depression of the detector rod  208 . 
     Accordingly, in exemplary embodiments, depression of the detector rod  208  may be indicative of an attempt to mate the cassette  100  to the fluidics module  122 . More particularly, depression of at least two detector rods  208  positioned about the cassette receiver  123  may be indicative of an alignment or attitude of the cassette  100  as the attempt is made to mate the cassette  100  to the fluidics module  122 . In an exemplary embodiment, the mounting position may preferably comprise, in an exemplary two-potentiometer embodiment, a substantially diagonal mounting with respect to the plane provided by the mouth of the cassette receiver  123  of the fluidics module  122 , and this diagonal mounting may be as far diagonal as is practicable. 
     Each potentiometer  202  in a two potentiometer embodiment may thus register a linear amount traveled once in contact with a back face of the cassette  100 , i.e., at the point of initial insertion of the cassette  100  to the cassette receiver  123 . The two potentiometers in conjunction may thus also provide a differential in the dimensional amount traveled by each plunger shaft  204  relative to the other, thereby indicating the tilt, angle, or attitude on-plane or off-plane of the cassette  100  from the plane at the mouth of the cassette receiver  123 . This differential may be assessed, for example, using a comparator included in controller  40  that receives and compares an electrical resistance reading of each potentiometer. An angle off-plane of a sufficient amount may prevent actuation of the clamping mechanism for the cassette  100 , thereby preventing jamming and thus requiring that an operator remove the cassette  100  and re-approach the cassette  100  to the cassette receiver  123 . 
       FIGS. 20 a  and 20 b    are cross-sectional schematic illustrations of the rear and front views, respectively, of an exemplary embodiment of the fluidics module  122  and cassette receiver  123 , in which two potentiometers  202  are used to detect alignment and attitude of a cassette  100  as it is pushed toward a fluidics module  122 . In the illustrated embodiment, the potentiometers  202  reside on the fluidics module  122 , although the potentiometers  202  may also reside on the cassette  100 , as referenced above. Further, although in the illustrated embodiment two potentiometers  202  are shown diagonally about the cassette receiver  123  of the fluidics module  122 , any number of potentiometers greater than two, and in any one of several configurations, may be used to provide a more refined indication of alignment and attitude of the cassette  100 . For example, four potentiometers may be used, one adjacent to each of the four “corners” about the cassette receiver  123 . 
     In the rear view illustration, the two potentiometers  202  may be mounted at two corners about the cassette receiver  123  using the mounting bodies  210  discussed above. The mounting bodies  210  may be mounted using, for example, a screw or bolt placed through a hole in the mounting body  210  and screwed or bolted into the rear of the fluidics module  122 . Upon mounting, and as shown in the front view illustration, the respective detector rods  208  of each potentiometer  202  extend to the front of the fluidics module  122 , i.e., into the cassette receiver  123 , through holes extending from the rear of the fluidics module  122  to the front of the fluidics module  122 . 
     Accordingly, a full traverse by each potentiometer shaft  204  (or a linear traverse to a predetermined point) may not only be indicative of a proper planar attitude and correct alignment of the cassette  100  to the mounting plane, but may further be indicative that the cassette  100  is fully inserted, or loaded, into the cassette receiver  123 . Thus, a full linear traverse (or a linear traverse to a predetermined point) by both (or all, in embodiments having more than two) potentiometer shafts  204  may serve as an additional “switch” indicating a full and complete insertion of the cassette  100 , thereby allowing for continued normal operation of any clamping mechanism and of the union of fluidics module  122  and cassette  100 . 
     The mounting of the potentiometers  202  to the fluidics module  122  may be greatly simplified using the illustrated embodiments as compared to alignment sensors generally provided in the prior art. This may be the case at least because adjustment of optical sensors, reading of voltmeters, and set screw adjustment and lock down adjustment may be avoided. 
     Further, the use of the potentiometers  202 , or like detectors of variations in resistance, allows for the sensing of attitude and alignment, and variations therein, in real time. Thereby, motors associated with any of the clamping mechanisms discussed throughout may calibrate and/or adjust dynamically. That is, motor activation and speed may be dynamically adjusted to actuate clamps and/or to actuate doors to receive the cassette  100 , and/or to release the cassette  100 , such as to account for the attitude or alignment of the cassette  100  approaching cassette receiver  123 . As used herein, actuation of clamps may include clamping and unclamping, and actuation of doors may include opening and closing. Additionally, motor activation and speed, and/or pump actuation and speed, by fluidics module  122  may adjust dynamically during operation, such as if the cassette  100  changes position slightly due to being bumped, or the like. 
     All references cited herein are hereby incorporated by reference in their entirety including any references cited therein. 
     Although the present invention has been described in terms of specific embodiments, changes and modifications can be carried out without departing from the scope of the invention which is intended to be limited only by the scope of the claims.

Technology Classification (CPC): 8