Abstract:
A tip for a surgical handpiece having two coaxial tubes or channels mounted within a body. The tip has one or more features that shape the fluid discharge so as to optimize the performance of the handpiece for varying parts of the surgical procedure.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     This invention relates generally to the field of cataract surgery and more particularly to a handpiece tip for practicing the liquefracture technique of cataract removal.  
         [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 liquifies 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]     Recently, a new cataract removal technique has been developed that involves the injection of hot (approximately 45° C. to 105° C.) water or saline to liquefy or gellate the hard lens nucleus, thereby making it possible to aspirate the liquefied lens from the eye. Aspiration is conducted concurrently with the injection of the heated solution and the injection of a relatively cool solution, thereby quickly cooling and removing the heated solution. This technique is more fully described in U.S. Pat. No. 5,616,120 (Andrew, et al.), the entire content of which is incorporated herein by reference. The apparatus disclosed in the publication, however, heats the solution separately from the surgical handpiece. Temperature control of the heated solution can be difficult because the fluid tubes feeding the handpiece typically are up to two meters long, and the heated solution can cool considerably as it travels down the length of the tube.  
         [0006]     U.S. Pat. No. 5,885,243 (Capetan, et al.) discloses a handpiece having a separate pumping mechanism and resistive heating element. Such a structure adds unnecessary complexity to the handpiece.  
         [0007]     U.S. Pat. No. 6,579,270 B2 (Sussman, et al.) discloses a surgical handpiece and tip having two coaxial tubes or channels mounted within a body. The first tube is used for aspiration and is smaller in diameter than the second tube so as to create an annular passage between the first and second tube. The annular passage communicates with a pumping chamber formed between two electrodes. The pumping chamber works by boiling a small volume of the surgical fluid. As the fluid boils, it expands rapidly, thereby propelling the liquid downstream of the pumping chamber out of the annular passage. The distal end of the annular gap is sealed by a nozzle at the distal ends of the first and second tube and a plurality of orifices or ports may be formed in the nozzle. As the expanding gas is propelled down the annular gap, the gas/liquid stream is forced out of the distal orifice in a controlled and directed manner. However, aspiration and irrigation flow patterns different that those described in this patent are sometimes desired, such as during cortical clean up or posterior capsule washing or lavage.  
         [0008]     Therefore, a need continues to exist for a simple surgical handpiece and tip that can heat internally the solution used to perform the liquefracture technique.  
       BRIEF SUMMARY OF THE INVENTION  
       [0009]     The present invention improves upon the prior art by providing a tip for a surgical handpiece having two coaxial tubes or channels mounted within a body. The tip has one or more features that shape the fluid discharge so as to optimize the performance of the handpiece for varying parts of the surgical procedure.  
         [0010]     Accordingly, one objective of the present invention is to provide a tip for a surgical handpiece having at least two coaxial tubes.  
         [0011]     Another objective of the present invention is to provide a tip for a handpiece having a pumping chamber.  
         [0012]     Another objective of the present invention is to provide a tip for a surgical handpiece having a device for delivering the surgical fluid through the handpiece in pulses.  
         [0013]     Still another objective of the present invention is to provide a tip for a handpiece that delivers fluid pulses in a controlled and directed manner.  
         [0014]     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  
       [0015]      FIG. 1  is a partial front, upper left perspective view of a first embodiment of the handpiece tip of the present invention.  
         [0016]      FIG. 2  is a partial cross-sectional view of the handpiece tip illustrated in  FIG. 1 .  
         [0017]      FIG. 3  is a partial front, upper left perspective view of a second embodiment of the handpiece tip of the present invention.  
         [0018]      FIG. 4  is a partial cross-sectional view of the handpiece tip illustrated in  FIG. 3 .  
         [0019]      FIG. 5  is a partial front, upper left perspective view of a third embodiment of the handpiece tip of the present invention.  
         [0020]      FIG. 6  is a partial front, upper left perspective view of a third embodiment of the handpiece tip of the present invention similar to  FIG. 5 , but illustrating a fluid stream exiting the tip.  
         [0021]      FIG. 7  is a partial front, upper right perspective view of a fourth embodiment of the handpiece tip of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0022]     Handpieces suitable for use with the present invention include the INFINITI® AQUALASE® surgical system which is commercially available from Alcon Laboratories, Inc., Fort Worth, Tex. This system uses a tip generally described in FIGS. 23 and 24 and column 7, lines 33-45 of U.S. Pat. No. 6,579,270 B2 (Sussman, et al.) and these portions of such patent are specifically incorporated herein by reference. As described in this patent, tip  900  may alteratively consist of outer tube  965  surrounding and coaxial with inner tube  967 . Distal tip  902  of outer tube  965  is flared or belled so as to allow nozzle  905  to be inserted between outer tube  965  and inner tube  967 . As best seen in  FIG. 23 , nozzle  905  contains fluid channel  907  that communicates with orifice  904 . Nozzle  905  seals annular gap  969  between outer tube  965  and inner tube  967 . Pressurized fluid flowing down annular gap  969  is forced into fluid channel  907  and out orifice  904 .  
         [0023]     As best seen in  FIGS. 1 and 2 , in a first embodiment, tip  10  of the present invention generally includes rounded tip cap or body  12  having aspiration port  14  and irrigation port  16 . Body  12  seals annular gap  18  between outer irrigation tube  20  and inner aspiration tube  22 . Aspiration port  14  is offset at an angle relative to centerline  11  of outer tube  20  and inner tube  22  and irrigation port  16  is likewise offset at an angle relative to centerline  11  of outer tube  20  and inner tube  22 . Aspiration port  14  is generally smaller in diameter than inner tube  22 . Such a construction directs the pulses of heated fluid exiting irrigation port  16  away from aspiration port  14 . Such a construction is particularly useful during the irrigation/aspiration (“I/A”) portion of a lens removal surgical procedure, such as cortical clean up.  
         [0024]     As best seen in  FIGS. 3 and 4 , in a second embodiment, tip  110  of the present invention generally includes rounded body  112  having aspiration port  114  and irrigation port  116 . Body  112  seals annular gap  118  between outer irrigation tube  120  and inner aspiration tube  122 . Tip  110  may also include outer soft silicone sleeve  124  providing a second source of irrigation. Irrigation port  116  is arcuate in shape. Aspiration port  114  and inner aspiration tube  122  are offset from centerline  111  of outer irrigation tube  120 . Such a construction directs the pulses of heated fluid exiting irrigation port  16  away from aspiration port  14 . Aspiration port  114  is generally smaller in diameter than inner tube  122 . Such a construction is particularly useful during the posterior capsule polishing or posterior capsule lavage portion of a lens removal surgical procedure.  
         [0025]     As best seen in  FIGS. 5 and 6 , in a third embodiment, tip  210  has a construct very similar to tip  900  and nozzle  905  as described in U.S. Pat. No. 6,579,270 B2 (Sussman, et al.). Cylindrical body  212  seals the annular gap between outer irrigation tube  220  and inner aspiration tube  222 . Aspiration port  214  is cylindrical and located centrally and coaxially with outer irrigation tube  220  and inner aspiration tube  222 . Port  214  contains groove or notch  215  against which, fluid exiting nozzle port  216  is directed. As best seen in  FIG. 6 , such a construction cause fluid  217  exiting tip  210  to be more narrowly focused and not spread out in a fan shaped pattern. One skilled in the art will recognize that notch  215  may be of any desired shape, such as straight-walled (as illustrated in  FIGS. 5 and 6 ), converging or diverging. Alternatively, as seen in  FIG. 7 , port  314  in body  312  on tip  310  may contain raised obstruction  315  an any suitable size and shape so as to disperse fluid  317  in any desired spray pattern.  
         [0026]     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. For example, it will be recognized by those skilled in the art that the present invention may be combined with ultrasonic and/or rotating cutting tips to enhance performance. In addittion, aspiration may or may not be used and the tips of the present invention may be used only as irrigation devices.