Patent Publication Number: US-2018049921-A1

Title: Phacoemulsification hand piece with integrated aspiration pump

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to phacoemulsification surgery and more particularly to a device that better regulates pressure experienced in the eye during cataract surgery. 
     The human eye functions to provide vision by transmitting light through a clear outer portion called the cornea, and focusing the image by way of a crystalline lens onto a 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 the 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. A typical surgical hand piece suitable for phacoemulsification procedures consists of an ultrasonically driven phacoemulsification hand piece, an attached hollow cutting needle surrounded by an irrigating sleeve, and an electronic control console. The hand piece assembly is attached to the control console by an electric cable and flexible tubing. Through the electric cable, the console varies the power level transmitted by the hand piece to the attached cutting needle. The flexible tubing supplies irrigation fluid to the surgical site and draws aspiration fluid from the eye through the hand piece assembly. 
     The operative part in a typical hand piece 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 needle during phacoemulsification, and are controlled by the console. The crystal/horn assembly is suspended within the hollow body or shell of the hand piece by flexible mountings. The hand piece body terminates in a reduced diameter portion or nosecone at the body&#39;s distal end. Typically, the nosecone is externally threaded to accept the hollow irrigation sleeve, which surrounds most of the length of the cutting needle. 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 needle is adjusted so that its tip projects only a predetermined amount past the open end of the irrigating sleeve. 
     During the phacoemulsification procedure, the tip of the cutting needle and the end of the irrigation sleeve are inserted into the anterior segment of the eye through a small incision in the outer tissue of the eye. The surgeon brings the tip of the cutting needle into contact with the lens of the eye, so that the vibrating tip fragments the lens. The resulting fragments are aspirated out of the eye through the interior bore of the cutting needle, along with irrigation solution provided to the eye during the procedure, and into a waste reservoir. 
     Throughout the procedure, irrigating fluid is pumped into the eye, passing between the irrigation sleeve and the cutting needle and exiting into the eye at the tip of the irrigation sleeve and/or from one or more ports, or openings, cut into the irrigation sleeve near its end. This irrigating fluid is critical, as it prevents the collapse of the eye during the removal of the emulsified lens. The irrigating fluid also protects the eye tissues from the heat generated by the vibrating of the ultrasonic cutting needle. Furthermore, the irrigating fluid suspends the fragments of the emulsified lens for aspiration from the eye. 
     A common phenomenon during a phacoemulsification procedure arises from the varying flow rates that occur throughout the surgical procedure. Varying flow rates result in varying pressure losses in the irrigation fluid path from the irrigation fluid supply to the eye, thus causing changes in pressure in the anterior chamber (also referred to as Intra-Ocular Pressure or IOP.) Higher flow rates result in greater pressure losses and lower IOP. As IOP lowers, the operating space within the eye diminishes. 
     Another common complication during the phacoemulsification process arises from a blockage, or occlusion, of the aspirating needle. As the irrigation fluid and emulsified tissue is aspirated away from the interior of the eye through the hollow cutting needle, pieces of tissue that are larger than the diameter of the needle&#39;s bore may become clogged in the needle&#39;s tip. While the tip is clogged, vacuum pressure builds up within the tip. The resulting drop in pressure in the anterior chamber in the eye when the clog is removed is known as post-occlusion surge. This post-occlusion surge can, in some cases, cause a relatively large quantity of fluid and tissue to be aspirated out of the eye too quickly, potentially causing the eye to collapse and/or causing the lens capsule to be torn. 
     Various techniques, such as venting the aspiration line, have been designed to reduce this surge. However, there remains a need for improved phacoemulsification devices that reduce post-occlusion surge as well as maintain a stable TOP throughout varying flow conditions. 
     SUMMARY OF THE INVENTION 
     In one embodiment consistent with the principles of the present invention, the present invention is an ophthalmic surgical hand piece comprising a driver coupled to a horn, the horn coupled to a needle an aspiration pump integral with the hand piece, the aspiration pump located close to the needle; and a rigid length of aspiration line located between the aspiration pump and the needle. 
     In another embodiment consistent with the principles of the present invention, the present invention is an ophthalmic surgical hand piece comprising a driver coupled to a horn, the horn coupled to a needle an aspiration pump integral with the hand piece, the aspiration pump located close to the needle; a disposable segment coupled to the aspiration pump; and a rigid length of aspiration line located between the aspiration pump and the needle. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are intended to provide further explanation of the invention as claimed. The following description, as well as the practice of the invention, set forth and suggest additional advantages and purposes of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several embodiments of the invention and together with the description, serve to explain the principles of the invention. 
         FIG. 1  is a diagram of the components in the fluid path of a phacoemulsification system including a hand piece with an integrated aspiration pump according to the principles of the present invention. 
         FIG. 2  is a block diagram of a phacoemulsification hand piece with an integrated aspiration pump according to the principles of the present invention. 
         FIG. 3  is a block diagram of a phacoemulsification hand piece with an integrated aspiration pump according to the principles of the present invention. 
         FIG. 4  is a side view of a portion of a phacoemulsification hand piece with an integrated aspiration pump according to the principles of the present invention. 
         FIG. 5  is a cross section view of a portion of a phacoemulsification hand piece with an integrated aspiration pump according to the principles of the present invention. 
         FIG. 6  is a side view of a removable cartridge for use with a phacoemulsification hand piece with an integrated aspiration pump according to the principles of the present invention. 
         FIGS. 7  is a perspective view of a removable cartridge for use with a phacoemulsification hand piece with an integrated aspiration pump according to the principles of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Reference is now made in detail to the exemplary embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used throughout the drawings to refer to the same or like parts. 
       FIG. 1  is a diagram of the components in the fluid path of a phacoemulsification system including a hand piece with an integrated aspiration pump according to the principles of the present invention.  FIG. 1  depicts the fluid path through the eye  145  during cataract surgery. The components include an irrigation source  120 , an optional irrigation pressure sensor  130 , an optional irrigation valve  135 , an irrigation line  140 , a hand piece  150 , an aspiration line  155 , an optional aspiration pressure sensor  160 , an optional vent valve  165 , a pump  170 , a reservoir  175  and a drain bag  180 . The irrigation line  140  provides irrigation fluid to the eye  145  during cataract surgery. The aspiration line  155  removes fluid and emulsified lens particles from the eye during cataract surgery. 
     When irrigation fluid exits irrigation source  120 , it travels through irrigation line  140  and into the eye  145 . An irrigation pressure sensor  130  measures the pressure of the irrigation fluid in irrigation line  140 . An optional irrigation valve  135  is also provided for on/off control of irrigation. Irrigation pressure sensor  130  is implemented by any of a number of commercially available fluid pressure sensors. 
     A hand piece  150  is placed in relation to the eye  145  during a phacoemulsification procedure. The hand piece  150  has a hollow needle ( 270  in  FIGS. 2 &amp; 3 ) that is ultrasonically vibrated in the eye to break up the diseased lens. A sleeve located around the needle provides irrigation fluid from irrigation line  140 . The irrigation fluid passes through the space between the outside of the needle and the inside of the sleeve. Fluid and lens particles are aspirated through the hollow needle. In this manner, the interior passage of the hollow needle is fluidly coupled to aspiration line  155 . Pump  170  draws the aspirated fluid from the eye  145 . An optional aspiration pressure sensor  160  measures the pressure in the aspiration line. An optional vent valve can be used to vent the vacuum created by pump  170 . The aspirated fluid passes through reservoir  175  and into drain bag  180 . 
       FIG. 2  is a block diagram of a phacoemulsification hand piece with an integrated aspiration pump according to the principles of the present invention. In  FIG. 2 , hand piece  150  comprises motor  210 , shaft  220 , removable cartridge  230 , optional aspiration pressure sensor  160 , driver  250 , horn  260 , needle  270 , and aspiration line  280 . Motor  210  rotates shaft  220 . When the pump is in operation, removable cartridge  230  is held against shaft  220 . Aspiration pressure sensor  160  is located between removable cartridge  230  and the eye  145 . 
     In  FIG. 2 , the pump  170  comprises motor  210 , shaft  220 , and flexible tubing in removable cartridge  230 . In one embodiment of the present invention, shaft  220  has a spiral structure that presses against the flexible tubing in removable cartridge  230 . In this manner, a screw-type or scroll-type aspiration pump is implemented with motor  210 , shaft  220 , and flexible tubing in removable cartridge  230 . This is more clearly shown and described in  FIGS. 4 and 5 . While pump  170  is described as a screw-type pump, other types of pumps may also be used. 
     Aspiration line  280  is fluidly coupled to removable cartridge  230 . Aspiration line also extends through or around drive  250 , horn  260 , and needle  270 . A lumen in needle  270  is fluidly coupled to aspiration line  280 . As described above, fluid and lens particles are aspirated through the lumen of needle  270 . Aspiration pump  170  draws fluid and lens particles through the lumen of needle  270 . 
     Driver  250  is typically an ultrasonic driver that produces ultrasonic vibrations in horn  260 . Horn  260  is typically a mass of metal that is coupled to driver  250  and needle  270 . In this manner, vibrations produced by driver  250  are transferred to horn  260  and to needle  270 . Needle  270  is placed in the eye and vibrated to fragment a cataractous lens. 
     Aspiration pressure sensor  160  measures the aspiration pressure in aspiration line  280 . While shown as located between removable cartridge  230  and driver  250 , aspiration pressure sensor may be located at any location between pump  170  and the eye  145 . Aspiration pressure sensor  160  may be implemented by any of a number of known pressure sensor devices. 
       FIG. 3  is a block diagram of a phacoemulsification hand piece with an integrated aspiration pump according to the principles of the present invention. The example of  FIG. 3  has the elements of  FIG. 2  plus an optional vent valve  165 . When optional vent valve  165  is present, it acts to provide a venting path for the aspiration pump  170 . In this manner, pump  170  can be vented, for example, to atmosphere when vent valve  165  is opened. As shown in  FIG. 3 , aspiration line  280  has two paths—one path that goes through removable cartridge  230 , and another path that goes around removable cartridge  230 . This second path (that goes around removable cartridge  230 ) and associated vent valve  165  may also be incorporated into removable cartridge  230 . When vent valve  165  is opened, the aspiration or vacuum produced by pump  170  is decreased as a result of it being vented to atmosphere. 
       FIGS. 4 and 5  are side and cross section views, respectively, of a portion of a phacoemulsification hand piece with an integrated aspiration pump according to the principles of the present invention.  FIGS. 4 and 5  more clearly show the details of one example of a removable cartridge  230  and pump  170 . In the example shown, removable cartridge  230  comprises aspiration line coupling  405 , first tubing coupling  420 , tubing holder  440 , and lever  430 . These components are integrated into a frame as shown. Removable cartridge  230  can be removed from the remainder of the hand piece. 
     In the example of the removable cartridge shown in  FIGS. 4 and 5 , aspiration line coupling  405  can be attached to aspiration tubing that is coupled to the surgical console. In this manner, aspiration line coupling  405  is near the end of the hand piece that is connected to the surgical console. A tube extends from aspiration line coupling  405  to first tubing coupling  420 . This tube is a part of the aspiration line  280  shown in  FIGS. 2 and 3 . 
     Tubing holder  440  holds a flexible tube (not shown) that is located between shaft  220  and tubing holder  440 . Shaft  220  presses the flexible tubing against tubing holder  440 . As shaft  220  rotates, the spiral protrusion on shaft  220  pumps fluid through the flexible tubing (thus implementing a screw-type or scroll-type pump). Tubing holder  440  is made of a rigid material that is suitable for holding flexible tubing. One end of the flexible tubing is fluidly coupled to first tubing coupling  420 , and the other end of the flexible tubing is fluidly coupled to second tubing coupling  425 . In this manner, the flexible tubing is a part of the aspiration line  280 . 
     Lever  430  operates to secure removable cartridge  230  to the remainder of the hand piece. While shown as a lever, other mechanisms can be employed to secure removable cartridge to the remainder of the hand piece. 
     Motor  210  is coupled to shaft  220  and serves to rotate shaft  220 . Motor  210  can be controlled to control the movement of shaft  220  as more clearly described below. Motor  210  is typically a DC motor but can be any type of motor or driver suitable for rotating shaft  220 . 
     In the example of  FIGS. 4 and 5 , a connector  450  connects the flexible tubing held by tubing holder  440  to the hand piece coupling  415 . Connector coupling  410  interfaces with hand piece coupling  415 —either directly or via another part. In this manner, the aspiration path passes through hand piece coupling  415 , connector coupling  410 , connector  450 , second tubing coupling  425 , the flexible tubing held by tubing holder  440 , first tubing coupling  420  and aspiration line coupling  405 . Connector  450  is connected to an end of shaft  220 . In this manner, connector  450 , shaft  220 , and motor  210  (along with the frame that holds these parts) is attached to the driver  250  (which is coupled to the horn  260  and the needle  270 ). 
     The length of aspiration line between the pump and the eye (i.e. between second tubing coupling  425  and needle  270 ) is minimal (on the order of inches). In addition, this length of aspiration line between the pump and the eye may be non-compliant (i.e. it can be rigid). Having a small length of non-compliant tubing between the pump  170  and the eye eliminates the surge associated with prior art systems. 
     In operation, motor  210  rotates shaft  220 . A controller (not shown) controls the operation of motor  210 . In this manner, shaft  220  may be rotated at any desired speed to produce any desired vacuum. Further, shaft  220  may be stopped or rotated in an opposite direction if desired. In this manner, motor  210  may be controlled to rotate shaft  220  in either direction. When rotated, shaft  220  draws fluid through the flexible tube and acts to pump the fluid through the aspiration line. 
     In another example, shaft  220  can be moved toward and away from tubing holder  440 . In this manner, the space between tubing holder  440  and shaft  220  can be varied so that the flexible tubing can be pinched to different degrees between shaft  220  and tubing holder  440 . In other words, shaft  220  can pinch the flexible tubing held by tubing holder  440  very tightly to produce pumping action that does not allow for leakage. Alternatively, as shaft  220  is moved away from tubing holder  440 , the flexible tubing is pinched less tightly thus leading to a leakage and less of a vacuum or pumping force. The position of shaft  220  with respect to tubing holder  440  can be variably controlled to adjust the leakage through the flexible tubing, and in turn adjust the vacuum produced by the pump. 
     In another example (shown in  FIG. 3 ), the position of shaft  220  with respect to tubing holder  440  can be fixed, and a vent valve  165  can be used to produce leakage that adjusts the vacuum produced by the pump. In this manner, vent valve  165  can be variably controlled to control the amount of vacuum that is present in the aspiration line (by controlling the amount of leakage through vent valve  165 ). 
     The control of aspiration vacuum can be based on a reading from aspiration pressure sensor  160 . Aspiration pressure sensor  160  is located between the pump and the eye. In this manner, aspiration pressure sensor  160  accurately reads the pressure conditions in the aspiration line very close to the eye. Such a reading can be used to precisely control the aspiration vacuum that is applied to the eye. 
       FIGS. 6 and 7  are side and perspective views, respectively, of a removable cartridge for use with a phacoemulsification hand piece with an integrated aspiration pump according to the principles of the present invention. In the example of  FIGS. 6 and 7 , the removable cartridge comprises aspiration line coupling,  405 , first tubing coupling  420 , tubing holder  440 , lever  430 , and opening  605 . Opening  605  interfaces with second tubing coupling  425  as shown in  FIG. 5 . A piece of flexible tubing is located between first tubing coupling  420  and opening  605 . The removable cartridge  230  of  FIGS. 6 and 7  can be reusable or disposable. In one example, the removable cartridge is reusable and the flexible tubing in disposable. In another example, the removable cartridge is disposable along with the flexible tubing. 
     The design of the present invention allows for the aspiration pump  170  to be very close to the eye  145 . The distance between the aspiration pump  170  and the eye  145  can be made to be very small—on the order of inches. Placing the aspiration pump  170  close to the eye  145  allows for a very short length of aspiration line to be located between the pump  170  and the eye  145 . Moreover, the length of aspiration line located between the pump  170  and the eye  145  can be rigid (for example, it can be made of stainless steel). This short length of non-compliant material that makes up the aspiration line between the pump  170  and the eye  145  eliminates any surge effect associated with conventional phacoemulsification systems. 
     In conventional phacoemulsification systems, the aspiration pump is located in a console. A relatively long length of flexible tubing (six feet or more) is located between the aspiration pump and the eye. This relatively long length of flexible tubing has a lot of compliance—it can stretch in response to changes in vacuum pressure. This compliance results in surges as previously described. By incorporating the aspiration pump in the hand piece (and placing it very close to the eye) and having a very short length of non-compliant tubing between the aspiration pump and the eye, these surges can be eliminated, thus resulting in a safer and more efficient surgery. 
     From the above, it may be appreciated that the present invention provides a pressurized infusion system for phacoemulsification surgery. The present invention provides an irrigation squeeze band device that more precisely controls fluid pressure. The present invention is illustrated herein by example, and various modifications may be made by a person of ordinary skill in the art. 
     Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.