Abstract:
An infusion control system having a flexible, collapsible infusion container. The container can be compressed between rollers or plate so at to pressurize the container. Such a system allows for rapid pressure response rates without the need of venting devices or air filtering. The may also include an irrigation flow sensor. The sensor may be placed in the control console or in the infusion handpiece. Irrigation flow measurements provided by the sensor allows the control system to vary irrigation pressure and/or flow, aspiration pressure and/or flow and power supplied to the handpiece more accurately than sensors that monitor aspiration flow.

Description:
This application is a continuation-in-part application of U.S. patent application Ser. No. 09/336,230, filed Jun. 18, 1999 now U.S. Pat. No. 6,179,808. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates generally to the field of cataract surgery and more particularly to an infusion control system for a phacoemulsification handpiece. 
     The human eye in its simplest terms functions to provide vision by transmitting light through a clear outer portion called the cornea, and focusing the image by way of the lens onto the retina. The quality of the focused image depends on many factors including the size and shape of the eye, and the transparency of the cornea and lens. 
     When age or disease causes the lens to become less transparent, vision deteriorates because of the diminished light which can be transmitted to the retina. This deficiency in the lens of the eye is medically known as a cataract. An accepted treatment for this condition is surgical removal of the lens and replacement of the lens function by an artificial intraocular lens (IOL). 
     In the United States, the majority of cataractous lenses are removed by a surgical technique called phacoemulsification. During this procedure, a thin phacoemulsification cutting tip is inserted into the diseased lens and vibrated ultrasonically. The vibrating cutting tip liquefies or emulsifies the lens so that the lens may be aspirated out of the eye. The diseased lens, once removed, is replaced by an artificial lens. 
     A typical ultrasonic surgical device suitable for ophthalmic procedures consists of an ultrasonically driven handpiece, an attached cutting tip, and irrigating sleeve and an electronic control console. The handpiece assembly is attached to the control console by an electric cable and flexible tubings. Through the electric cable, the console varies the power level transmitted by the handpiece to the attached cutting tip and the flexible tubings supply irrigation fluid to and draw aspiration fluid from the eye through the handpiece assembly. 
     The operative part of the handpiece is a centrally located, hollow resonating bar or horn directly attached to a set of piezoelectric crystals. The crystals supply the required ultrasonic vibration needed to drive both the horn and the attached cutting tip during phacoemulsification and are controlled by the console. The crystal/horn assembly is suspended within the hollow body or shell of the handpiece by flexible mountings. The handpiece body terminates in a reduced diameter portion or nosecone at the body&#39;s distal end. The nosecone is externally threaded to accept the irrigation sleeve. Likewise, the horn bore is internally threaded at its distal end to receive the external threads of the cutting tip. The irrigation sleeve also has an internally threaded bore that is screwed onto the external threads of the nosecone. The cutting tip is adjusted so that the tip projects only a predetermined amount past the open end of the irrigating sleeve. Ultrasonic handpieces and cutting tips are more fully described in U.S. Pat. Nos. 3,589,363; 4,223,676; 4,246,902; 4,493,694; 4,515,583; 4,589,415; 4,609,368; 4,869,715; 4,922,902; 4,989,583; 5,154,694 and 5,359,996, the entire contents of which are incorporated herein by reference. 
     In use, the ends of the cutting tip and irrigating sleeve are inserted into a small incision of predetermined width in the cornea, sclera, or other location. The cutting tip is ultrasonically vibrated along its longitudinal axis within the irrigating sleeve by the crystal-driven ultrasonic horn, thereby emulsifying the selected tissue in situ. The hollow bore of the cutting tip communicates with the bore in the horn that in turn communicates with the aspiration line from the handpiece to the console. A reduced pressure or vacuum source in the console draws or aspirates the emulsified tissue from the eye through the open end of the cutting tip, the cutting tip and horn bores and the aspiration line and into a collection device. The aspiration of emulsified tissue is aided by a saline flushing solution or irrigant that is injected into the surgical site through the small annular gap between the inside surface of the irrigating sleeve and the cutting tip. 
     The preferred surgical technique is to make the incision into the anterior chamber of the eye as small as possible in order to reduce the risk of induced astigmatism. These small incisions result in very tight wounds that squeeze the irrigating sleeve tightly against the vibrating tip. Friction between the irrigating sleeve and the vibrating tip generates heat, but the risk of the tip overheating and causing a burn to the tissue is reduces by the cooling effect of the aspirated fluid flowing inside the tip. When the tip becomes occluded with tissue, this aspiration flow can be reduced or eliminated, allowing the tip to heat up. 
     Prior art devices have used sensors that detect large rises in aspiration vacuum, and predict occlusions based on vacuum rise. Based on this sensed occlusion, power to the handpiece may be reduced and/or irrigation and aspiration flows can be increased. See U.S. Pat. Nos. 5,591,127, 5,700,240 and 5,766,146 (Barwick, Jr., et al.), the entire contents of which being incorporated herein by reference. Increased vacuum levels in the aspiration line, however, do not necessarily indicate that the flow of cooling fluid around the tip has been cut off. Even with the tightest incisions, some irrigating fluid will leak out between the wound and the outside of the irrigating sleeve. The wound leakage also provides additional cooling flow to the incision site, and measuring rises in aspiration vacuum alone does not necessarily indicate that a potential for a corneal burn exists. Therefore, power to the handpiece may be interrupted prematurely. 
     Prior art devices have also used gravity fed methods or pressurized gas sources for controlling surgical infusion pressure and flow. Gravity feed infusion methods, such as those illustrated in FIG. 8, provide a pressure and flow based on the height of a column of liquid. The higher the column, the greater the pressure and flow. The lower the column, the lower the pressure and flow. The surgeon controls the column height by raising or lowering the infusion bottle. Pressurized gas sources, such as those illustrated in FIG. 9, control the infusion pressure by increasing or decreasing the pressure inside the infusion bottle. The bottle is suspended at a constant height and a gas pressure pump is connected to the bottle. See U.S. Pat. Nos. 4, 813,927, 4,900,301, 5,032,111 and 5,047,009(Morris, et al.), the entire contents of which being incorporated herein by reference. Gravity feed methods have limitations on pressure response rates due to the requirements of raising and lowering the infusion bottle. Pressurized gas methods improve on the response rates but require cumbersome venting snorkel devices that complicate the surgical setup. Both methods require filtering of air or gas into the bottle to prevent contamination which is added cost and complexity 
     Therefore, a need continues to exist for an infusion source for a surgical applications that utilizes a better method of infusion pressure and flow. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention improves upon the prior art by providing an infusion system having a flexible, collapsible infusion container. The container can be compressed between rollers or plate so as to pressurize the container. Such a system allows for rapid pressure response rates without the need of venting devices or air filtering. The may also include an irrigation flow sensor. The sensor may be placed in the control console or in the infusion handpiece. Irrigation flow measurements provided by the sensor allows the control system to vary irrigation pressure and/or flow, aspiration pressure and/or flow and power supplied to the handpiece more accurately than sensors that monitor aspiration flow. 
     Accordingly, one objective of the present invention is to provide a surgical console control system. 
     Another objective of the present invention is to provide a surgical console control system having irrigation flow sensing capability. 
     Another objective of the present invention is to provide a surgical console control system that provides more accurate control of the handpiece operating parameters. 
     Another objective of the present invention is to provide a surgical console control system that provides more accurate control of the infusion operating parameters. 
     Another objective of the present invention is to provide a surgical console control system that provides more accurate control of the aspiration operating parameters. 
     Another objective of the present invention is to provide faster and more accurate control of infusion pressure and flow. 
     Another objective of the present invention is to provide a method of infusion flow measurement without the need of external devices. 
     These and other advantages and objectives of the present invention will become apparent from the detailed description and claims that follow. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a block diagram of a first embodiment of a control system that can be used with the present invention. 
     FIG. 2 is a block diagram of a second embodiment of a control system that can be used with the present invention. 
     FIG. 3 is a block diagram of a third embodiment of a control system that can be used with the present invention showing the flow sensor in the instrument and pressurized infusion control of the infusion source. 
     FIG. 4 is a block diagram of a fourth embodiment of a control system that can be used with the present invention showing the flow sensor in the handpiece and pressurized infusion control of the infusion source. 
     FIG. 5 is a block diagram of a fifth embodiment of a control system that can be used with the present invention showing the flow sensor in the instrument and measuring air flow of the pressurized infusion source to calculate infusion fluid flow. 
     FIG. 6 is a block diagram of a sixth embodiment of a control system that can be used with the present invention showing the pressurized infusion source as a compressed compliant bag and the infusion fluid flow calculated from the rate of infusion source compression. 
     FIG. 7 is a flow chart illustrating the operation of an infusion flow control mode that can be used with the present invention. 
     FIG. 8 is an illustration of a prior art gravity fed infusion method. 
     FIG. 9 is an illustration of a prior art pressurized infusion method. 
     FIG. 10 is a block diagram of a one embodiment of the compliant container of the present invention being compressed between rollers. 
     FIG. 11 is a block diagram of another embodiment of the compliant container of the present invention being compressed by a pressure plate. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As seen in FIG. 1, in a first embodiment of the present invention, control system  10  for use in operating handpiece  12  includes control console  14 . Control console  14  generally includes control module or CPU  16 , aspiration pump  18 , handpiece power supply  20 , irrigation flow sensor  22  and valve  24 . Console  14  may be any commercially available surgical control console such as the ACCURUS® or LEGACY® SERIES TWENTY THOUSAND® surgical systems available from Alcon Laboratories, Inc., Fort Worth, Tex. CPU  16  may be any suitable microprocessor, micro controller, computer or digital logic controller. Pump  18  may be any suitable pump, such as a peristaltic, scroll, diaphragm or venturi pump. Power supply  20  may be any suitable ultrasound driver, such as incorporated in the ACCURUS® or LEGACY® SERIES TWENTY THOUSAND® surgical systems available from Alcon Laboratories, Inc., Fort Worth, Tex. Sensor  22  may be any commercially available flow sensor, such as Models Nos. T101D or T201D available from Transonic Systems, Inc., Ithaca, N.Y. Valve  24  may be any suitable valve such as a solenoid-activated pinch valve. Infusion source  26  may be any commercially available irrigation solution. 
     In use, sensor  22  is connected to handpiece  12  and infusion fluid source  26  through irrigation lines  30 ,  32  and  34 . Sensor  22  measures the flow of irrigation fluid from source  26  to handpiece  12  and supplies this information to CPU  16  through cable  36 . The irrigation fluid flow data may be used by CPU  16  to control the operating parameters of console  14  using software commands that are well-known in the art. For example, CPU  16 , through cable  38 , may open and close valve  24  so as to vary the amount of irrigation fluid reaching handpiece  12  from source  26 . CPU  16  may also, through cable  40 , vary the output of power supply  20  being sent to handpiece  12  though power cable  42 . CPU  16  may also use data supplied by sensor  22  to vary the operation of pump  18 , which aspirates fluid from handpiece  12  through line  46  and into collection container  28  through line  48 . 
     As seen in FIG. 2, in a second embodiment of the present invention, control system  110  for use in operating handpiece  112  includes control console  114 . Control console  114  generally includes control module or CPU  116 , aspiration pump  118 , handpiece power supply  120  and valve  124 . Flow sensor  122  is contained within handpiece  112 . 
     In use, tip  150  is connected to fluid source  126  through sensor  122  through irrigation lines  130 ,  132  and  134 . Sensor  122  measures the flow of irrigation fluid from source  126  to tip  150  and supplies this information to CPU  116  through cable  136 . CPU  116 , through cable  138 , may open and close valve  124  so as to vary the amount of irrigation fluid reaching tip  150  from source  126 . CPU  116  may also, through cable  140 , vary the output of power supply  120  being sent to handpiece  112  though power cable  142 . CPU  116  may also use data supplied by sensor  122  to vary the operation of pump  118 , which aspirates fluid from handpiece  112  through line  146  and into collection container  128  through line  148 . CPU  116  may also use data supplied by sensor  122  and the applied output of power supply  120  to provide audible tones to the user. 
     As seen in FIG. 3, in a third embodiment of the present invention, control system  210  for use in operating handpiece  212  includes control console  214 . Control console  214  generally includes control module or CPU  216 , aspiration pump  218 , handpiece power supply  220 , valve  224 , pressurizing source  229 , and pressure sensor  227 . Flow sensor  222  is connected to handpiece  212  and infusion fluid source  226  through irrigation lines  230 ,  232  and  234 . Infusion source  226  may be any commercially available irrigation solution provided in bottles. Pressurizing source  229  pressurizes infusion source  226  through line  252  and is controlled by CPU  216  through cable  250 . Pressurizing source  229  may be any commercially available pressure controller, such as incorporated in the ACCURUSO® surgical system available from Alcon Laboratories, Inc., Fort Worth, Tex. Pressure sensor  227  measures the pressure of infusion source  226  through lines  254  and is monitored by CPU  216  through cable  256 . Pressure sensor  227  may be any suitable commercially available pressure sensor, such as Model MPX5100 available from Motorola, Inc., Phoenix, Ariz. 
     In use, sensor  222  measures the flow of irrigation fluid from source  226  to handpiece  212  and supplies this information to CPU  216  through cable  236 . The irrigation fluid flow data may be used by CPU  216  to control the operating parameters of console  214  using software commands that are well known in the art. For example, CPU  216 , through cable  250 , may control pressurizing source  229  while reading pressure sensor  227  data through cable  256  so as to vary the pressure and amount of irrigation fluid reaching handpiece  212  from source  226 . CPU  216  may also, through cable  240 , vary the output of power supply  220  being sent to handpiece  212  through power cable  242 . CPU  216  may also use data supplied by sensor  222  to vary the operation of pump  218  through line  244 , which aspirates fluid from handpiece  212  through line  246  and into collection container  228  through line  248 . CPU  216  may also use data supplied by sensor  222  and the applied output of power supply  220  to provide audible tones to the user. 
     As seen in FIG. 4, in a fourth embodiment of the present invention, control system  310  for use in operating handpiece  312  includes control console  314 . Control console  314  generally includes control module or CPU  316 , aspiration pump  318 , handpiece power supply  320 , valve  324 , pressurizing source  329 , and pressure sensor  327 . Flow sensor  322  is contained within handpiece  312 . Infusion source  326  may be any commercially available irrigation solution provided in bottles. Pressurizing source  329  may be any commercially available pressure controller. Pressure sensor  327  may be any suitable commercially available pressure sensor. 
     In use, sensor  322  measures the flow of irrigation fluid from source  326  to handpiece  312  and supplies this information to CPU  316  through cable  336 . The irrigation fluid flow data may be used by CPU  316  to control the operating parameters of console  314  using software commands that are well known in the art. For example, CPU  316 , through cable  350 , may control pressurizing source  329  while reading pressure sensor  327  data through cable  356  so as to vary the pressure and amount of irrigation fluid reaching handpiece  312  from source  326 . CPU  316  may also, through cable  340 , vary the output of power supply  320  being sent to handpiece  312  through power cable  342 . CPU  316  may also use data supplied by sensor  322  to vary the operation of pump  318  through cable  344 , which aspirates fluid from handpiece  312  through line  346  and into collection container  328  through line  348 . CPU  316  may also use data supplied by sensor  322  and the applied output of power supply  320  to provide audible tones to the user. 
     As seen in FIG. 5, in a fifth embodiment of the present invention, control system  410  for use in operating handpiece  412  includes control console  414 . Control console  414  generally includes control module or CPU  416 , aspiration pump  418 , handpiece power supply  420 , valve  424 , pressurizing source  429 , and pressure sensor  527 . Airflow sensor  423  is connected to pressurizing source  429  and infusion source  426  through lines  432  and  452 . Sensor  423  may be any commercially available flow sensor, such as Model AWM3100V available from Honeywell Micro Switch, Freeport, Ill. Infusion source  426  may be any commercially available irrigation solution provided in bottles. 
     In use, sensor  423  measures the flow of air into the infusion source  426  and supplies this information to CPU  416  through cable  436 . The airflow data may be used by CPU  416  along with information from pressure sensor  427  for the calculation of infusion flow to the handpiece through line  434 . This infusion flow calculation may be used to control the operating parameters of console  414  using software commands that are well known in the art. For example, CPU  416 , through cable  450 , may control pressurizing source  429  while reading pressure sensor  427  data through cable  456  so as to vary the pressure and amount of irrigation fluid reaching handpiece  412  from source  426 . CPU  416  may also, through cable  440 , vary the output of power supply  420  being sent to handpiece  412  through power cable  442 . CPU  416  may also use this infusion flow calculation to vary the operation of pump  418  through cable  444 , which aspirates fluid from handpiece  412  through power cable  442 . CPU  416  may also use this infusion flow calculation to vary the operation of pump  418  through cable  444 , which aspirates fluid from handpiece  412  through line  446  and into collection container  428  through line  448 . CPU  416  may also use this infusion flow calculation and the applied output of power supply  420  to provide audible tones to the user. 
     As seen in FIG. 6, in a sixth embodiment of the present invention, control system  510  for use in operating handpiece  512  includes control console  514 . Control console  514  generally includes control module or CPU  516 , aspiration pump  518 , handpiece power supply  520 , valve  524 , pressurizing source  530 , and pressure sensor  527 . Infusion source  525  may be any commercially available irrigation solution provided in bags or a custom compliant container. Pressurizing source  530  is a compressing device that squeezes infusion source  525  through mechanism  553  in order to pressurize the fluid. The rate of compression of the infusion source is controlled by CPU  516  through cable  550 . 
     In use, CPU  516  calculates the infusion flow to the handpiece through line  534  based on the compression rate of pressurizing source  530  and the pressure data from pressure sensor  527 . This infusion flow calculation may be used to control the operating parameters of console  514  using software commands that are well known in the art. For example, CPU  516 , through cable  550 , may control pressurizing source  530  while reading pressure sensor  527  data through cable  556  so as to vary the pressure and amount of irrigation fluid reaching handpiece  512  from source  525 . CPU  516  may also, through cable  540 , vary the output of power supply  520  being sent to handpiece  512  through power cable  542 . CPU  516  may also use this infusion flow calculation to vary the operation of pump  518  through cable  544 , which aspirates fluid from handpiece  512  through line  546  and into collection container  528  through line  548 . CPU  516  may also use this infusion flow calculation and the applied out put of power supply  520  to provide audible tones to the user. 
     As seen in FIG. 10, pressurizing source  530  includes compression roller mechanism  553 , infusion container  525 , pressure sensor  527  and infusion or irrigation valve  524 . Roller mechanism  553  includes compression rollers  554  and rollers driving motor  555 . Infusion container  525  may be a compliant bag such as commonly supplied by Charter Medical, Lakewood, N.J., for surgical site infusion or a custom container specifically designed for this application. Infusion container  525  may be made from any suitable material that provides container collapse without excessive stretching. Infusion container  525  may be a thin wall bottle with or without corrugated sides (not shown). Pressure sensor  527  may be any commercially available, disposable, pressure sensor such as Model 1290C manufactured by Hewlett Packard or a custom type sensor specifically made for this application. Infusion valve  524  can be any commercially available pinch type valve commonly used in surgical instruments. Compression roller mechanism  553  may contain bi-directional mechanical rollers  554  and suitable fixturing specifically designed to compress compliant container  525  in a controlled and uniform manner such that the rate of compression is proportional to the rate of fluid expulsion. 
     In use, compliant container  525  is placed in roller mechanism  553  and connected to irrigation line  533 . Infusion valve  524  is opened and the roller mechanism  553  moves to compress container  525 . The movement of the rollers mechanism  554  reduces the available volume in container  525 , which forces the infusion liquid into irrigation line  533 . Information from pressure sensor  527  indicates the infusion pressure and roller mechanism  553  is controlled such that a predetermined infusion pressure reading is maintained. The rate of movement of driving motor  555  is proportional to the rate of liquid expulsion and the information may be used by control system  510  for further systematic control. 
     As seen in FIG. 11, pressurizing source  530 ′ includes infusion container  525 ′, mechanism  553 ′ pressure sensor  527 ′ and valve  524 ′. Mechanism  553 ′ includes compression actuators  103 , upper plate  105 , lower plate  107 , and plate return springs  106 . Compression actuators  103  may be either worm gear or hydraulically driven and designed to compress plate  105  in a controlled and uniform manner such that the rate of compression is proportional to the rate of fluid expulsion out of container  525 ′. Return springs  106  can be any commercially available springs used to return the plate to a previous position. 
     In use, compliant container  525 ′ is placed beneath upper plate  105  and lower plate  107  and connected to irrigation line  533 . Infusion valve  524 ′ is opened and actuators  103  operated so as to place downward pressure on plate  105  against springs  106 . Downward pressure on plate  105  squeezes container  525 ′ between upper plate  105  and lower plate  107 , thereby reducing the available volume in container  525 ′, which forces the infusion liquid into irrigation line  533 ′. Information from pressure sensor  527 ′ indicates the infusion pressure and actuators  103  are controlled such that a predetermined infusion pressure reading is maintained. The rate of movement of actuators  103  is proportional to the rate of liquid expulsion and the information may be used by control system  510  for further systematic control. 
     As seen in FIG. 7, when the system of the present invention is monitoring infusion flow, the system monitors the current infusion flow and compares the actual flow against a predetermined flow rate. If infusion flow is above the predetermined rate, no action is taken by the system. If the infusion flow is below the predetermined rate, the system may take a variety of actions, such as changing the power delivered to the ultrasound handpiece, providing a variable tone to the surgeon or changing the aspiration pressure. 
     This description is given for purposes of illustration and explanation. It will be apparent to those skilled in the relevant art that changes and modifications may be made to the invention described above without departing from its scope or spirit.