Abstract:
A method of priming a surgical system that includes pulling a very high vacuum and then cycling fluid through the system as a fluid pulse. These steps can be repeated a number of times to help ensure that residual entrained air is removed from the system.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    This invention relates generally to the field of cataract surgery and more particularly to a priming method for use with a phacoemulsification system. 
         [0002]    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. 
         [0003]    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). 
         [0004]    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. 
         [0005]    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. 
         [0006]    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. 
         [0007]    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. 
         [0008]    Prior to use in surgery, the various handpieces, tubings and fluid management cassettes all need to be purged of air or primed. During the priming stage, current phacoemulsification systems also run a system diagnostic step to test for leaks or blockages in the irrigation/aspiration system. Preferably the initial priming/diagnostic procedure is done prior to installation of the surgical handpiece by connecting the irrigation and aspiration fittings or lines together; however some equipment may perform this prime/diagnostic procedure with the surgical handpiece installed. During the diagnostic step, the system pump is activated to generate a certain vacuum in the aspiration line, generally around 400 mm Hg or less. If the system is not able to reach the desired vacuum level, this indicates to the system that there is a leak somewhere in the aspiration system, and the system will provide a warning for the operator. On the other hand, inability to release previously built vacuum indicates that there is a blockage in the system, such as a kink in one of the tubings. 
         [0009]    After connecting the surgical (phaco) handpiece, an additional diagnostic test is done to verify an adequate fluid flow through the surgical handpiece. Current phacoemulsification systems typically use a small rubber test chamber that fits over the cutting tip and sleeve to close the fluid path. During this test an excessive vacuum level in the aspiration line for a given pump speed would indicate a flow restriction in the fluidic path. Also, a manual check can be performed by the user to ensure that the closed system is filled and pressurized upon test completion. A deflated test chamber, for example, indicates an irrigation flow restriction. 
         [0010]    While this priming and diagnostic system procedure is effective, it is unable to remove all of the air from within the fluid system. Pockets of air remain entrained within the various passages due to fluid path geometry and/or surface tension. This residual entrained air adds to system compliance and has a deleterious effect on overall system performance. 
         [0011]    Therefore, a need continues to exist for a method of priming surgical systems that helps to purge air from the system. 
       BRIEF SUMMARY OF THE INVENTION 
       [0012]    The present invention improves upon the prior art by providing a method of priming a surgical system that includes pulling a very high vacuum and then cycling fluid through the system as a fluid pulse. These steps can be repeated a number of times to help ensure that residual entrained air is removed from the system. 
         [0013]    Accordingly, one objective of the present invention is to provide a surgical console control system. 
         [0014]    Another objective of the present invention is to provide a surgical console control system having a method for priming a surgical system. 
         [0015]    Another objective of the present invention is to provide a more reliable method for priming a surgical system that helps to purge entrained air from the system. 
         [0016]    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 
         [0017]      FIG. 1  is a block diagram of a surgical system capable of practicing the method of the present invention. 
           [0018]      FIG. 2  is a block diagram of a prior art second surgical system. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0019]    As best seen in  FIG. 2 , prior art surgical system  110  includes irrigation fluid source  112 , irrigation fluid supply line  114 , pump  116 , aspiration line  118  and drain bag  120 . During initial set up and priming, irrigation/aspiration junction  122  is formed in the manner described above. Irrigation fluid flow may flow from irrigation fluid source  112  to drain bag  120  because irrigation fluid source  112  is pressurized, but generally speaking, fluid flow through irrigation line  114 , irrigation/aspiration junction  122 , aspiration line  118  and into drain bag  120  is caused by the operation of pump  116 . The flow of irrigation fluid in irrigation fluid supply line  114  is controlled by irrigation valve  124  and check valve  129 . The vacuum in aspiration line  118  can be reduced or vented by operation of vent valve  126  that is placed in vent line  128 . Vent line  128  fluidly communicates between irrigation supply line  114  and aspiration line  118  between pump  116  and irrigation/aspiration junction  122 . System  110  is primed by closing vent valve  126 , opening irrigation valve  124  and operating pump  116  to produce a vacuum of generally around 500 mm Hg or more. Once irrigation line  114 , aspiration line  118  and pump  116  are primed, vent valve  26  is opened to prime vent line  128 . 
         [0020]    In order to purge residual entrained air from system  110 , irrigation valve  124  and vent valve  126  are closed, and pump  116  is operated to produce a high vacuum of around 600 mm Hg or greater in aspiration line  118 . Irrigation valve  124  is then opened, producing a sudden high flow pulse from bottle  112  through valve  124 , irrigation supply line  114 , irrigation/aspiration junction  122  and aspiration line  118 . Irrigation valve  124  is closed and pump  116  is once again operated to produce a high vacuum in aspiration line  118 . Vent valve  126  is then opened producing a sudden high flow pulse from bottle  112  through irrigation line  114 , valve  126  and vent line  128 . 
         [0021]    As best seen in  FIG. 1  surgical system  10  of the present invention generally includes irrigation fluid source  12 , irrigation fluid supply line  14 , pump  16 , aspiration line  18  and drain bag  20 . During initial set up and priming, for example, irrigation/aspiration junction  22  is formed by connecting irrigation line  14  and aspiration line  18  together directly or through a handpiece with a test chamber. Irrigation fluid flow may flow from irrigation fluid source  12  to drain bag  20  because irrigation fluid source  12  is pressurized, but generally speaking, fluid flow through irrigation line  14 , irrigation/aspiration junction  22 , aspiration line  18  and into drain bag  20  is caused by the operation of pump  16 . The flow of irrigation fluid in irrigation fluid supply line  14  is controlled by irrigation valve  24 . The vacuum in aspiration line  18  between pump  16  and irrigation/aspiration junction  22  can be reduced or vented by operation of vent valve  26  that is placed in vent line  28 . Vent line  28  fluidly communicates with both input side  17  and output side  15  of pump  16 . System  10  is primed by closing vent valve  26 , opening irrigation valve  24  and operating pump  16  to produce a vacuum of generally around 400 mm Hg or less. Once irrigation line  14 , aspiration line  18  and pump  16  are primed, vent valve  26  is opened to prime vent line  28 . 
         [0022]    Residual entrained air may be purged from difficult to prime passages within system  10  in the following manner. Irrigation valve  24  and vent valve  26  are closed, and pump  16  is operated to produce a high vacuum (e.g., at least 500 mm Hg and more preferably around 600 mm Hg or greater) in aspiration line  18 . Irrigation valve  24  is then opened, producing a sudden high flow pulse from bottle  12  through valve  24 , irrigation supply line  14 , irrigation/aspiration junction  22 , and aspiration line  18 . This sudden high flow condition helps to dislodge trapped air and adherent air bubbles within difficult to prime irrigation/aspiration passages, and pushes the air into the main flow path. Once the air is in the main flow path it is more easily removed from the system by operation of pump  16 . Irrigation valve  24  is closed and pump  16  is once again operated to produce a high vacuum in aspiration line  18 . Vent valve  26  is then opened producing a sudden high flow pulse from drain bag  20  through aspiration line  18  between drain bag  20  and output side  17  of pump  16 , vent line  28 , vent valve  26  and aspiration line  18  between input side  15  of pump  16  and irrigation/aspiration junction  22 . This sudden high flow condition helps to dislodge trapped air and adherent air bubbles within difficult to prime vent path passages and pushes the air into the main flow path. Once in the main flow path, air can more easily be removed from the system by operation of pump  16 . The above sequence may be repeated several times, if desired. 
         [0023]    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.