Abstract:
A phacoemulsification needle is provided for use with a high-frequency phacoemulsification handpiece with the needle tip having a land formed on the interior of the tip proximate the tip opening, creating a “stepped” configuration.

Description:
FIELD OF THE INVENTION 
       [0001]    This disclosure relates to surgical instruments and surgical techniques used in eye surgery and more particularly, to phacoemulsification needle tip designs for use with phacoemulsification handpieces. 
       PRIORITY 
       [0002]    This application claims priority from U.S. Patent Application Ser. No. 60/886,792, filed Jan. 26, 2007, which is incorporated herein by reference. 
       BACKGROUND OF THE INVENTION 
       [0003]    A common ophthalmological surgical technique is the removal of a diseased or injured lens from the eye. Earlier techniques used for the removal of the lens typically required a substantial incision to be made in the capsular bag in which the lens is encased. Such incisions were often on the order of 12 mm in length. 
         [0004]    Later techniques focused on removing diseased lenses and inserting replacement artificial lenses through as small an incision as possible. For example, it is now a common technique to take an artificial intraocular lens (IOL), fold it and insert the folded lens through the incision, allowing the lens to unfold when it is properly positioned within the capsular bag. Similarly, efforts have been made to accomplish the removal of the diseased lens through an equally small incision. 
         [0005]    One such removal technique is known as phacoemulsification. A typical phacoemulsification tool includes a handpiece to which is attached a hollow needle. Electrical energy is applied to vibrate the needle at ultrasonic frequencies in order to fragment the diseased lens into small enough particles to be aspirated from the eye through the hollow needle. Commonly, an infusion sleeve is mounted around the needle to supply irrigating liquids to the eye in order to aid in flushing and aspirating the lens particles. 
         [0006]    It is extremely important to properly infuse liquid during such surgery. Maintaining a sufficient amount of liquid prevents collapse of certain tissues within the eye and attendant injury or damage to delicate eye structures. As an example, endothelial cells can easily be damaged during such collapse and this damage is permanent because these cells do not regenerate. One of the benefits of using as small in incision as possible during such surgery is the minimization of leakage of liquid during and after surgery and the prevention of such a collapse. 
         [0007]    Phacoemulsification needles and tips are well represented in the prior art. Needles and tips of varying configurations are well known. A particular shape for a tip or needle is often dictated by the type of handpiece with which the needle is to be used. 
         [0008]    U.S. Pat. No. 5,725,495 (Strukel et al) teaches and describes a phacoemulsification handpiece, sleeve and tip illustrating a wide variety of tip configurations and needle cross-sectional configurations. 
         [0009]    U.S. Pat. No. 6,007,555 (Devine) teaches and describes an ultrasonic needle for surgical emulsification. The needle and its tip are shown in both circular and oval configurations. 
         [0010]    U.S. Pat. No. 6,605,054 (Rockley) teaches and describes a multiple bypass port phaco tip having multiple aspiration ports and a single discharge port to infuse liquid into the eye. 
         [0011]    U.S. Pat. No. 5,879,356 (Geuder) teaches and describes a surgical instrument for crushing crystalline eye lenses by means of ultrasound and for removing lens debris by suction which demonstrates the use of a sleeve positioned concentric to the needle and having a pair of discharge ports formed thereon. 
         [0012]    U.S. Pat. No. 5,645,530 (Boukhny) teaches and describes a phacoemulsification sleeve, one variation of which has a bellows portion attached to a discharge port ring which directs an annular flow of liquid around the needle and into the eye. The use of the bellows is intended to allow the sleeve to absorb spikes in liquid pressure during the operation. 
         [0013]    Published U.S. Patent Application No. 2003/0004455 (Kadziauskas) teaches and describes a bi-manual phaco needle using separate emulsification and aspiration needles inserted into the eye simultaneously during surgery. 
         [0014]    Published U.S. patent application 2006/0217672 (Chon) teaches and describes a phacoemulsification tip having a crimped or swaged tip end. 
         [0015]    U.S. Pat. No. 6,077,285 (Boukhny) teaches and describes a torsional ultrasound handpiece configured to impart both longitudinal and torsional motion to a phacoemulsification needle. 
         [0016]    U.S. Pat. No. 6,402,769 (Boukhny) is a continuation in part of the &#39;285 patent and further particularizes the frequencies at which the crystals providing both the torsional and longitudinal motion are activated. 
         [0017]    I have determined that improved results can be achieved using high-speed handpieces if the phacoemulsification tip is provided with a particular geometry. I have also determined that these improved results can be achieved using the straight phacoemulsification needle configuration, a configuration which is favored by a considerable number of doctors. 
         [0018]    In accordance with these criteria, I have designed tips that are specifically configured to enhance the emulsifying effect created by the handpiece. 
         [0019]    In accordance with an example of the invention, a phacoemulsification needle is provided for use with a high-frequency phacoemulsification handpiece with the needle tip having a land formed on the interior of the tip proximate the tip opening, creating a “stepped” configuration. 
         [0020]    In another example, the tip opening is formed at different angles. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]    These and further aspects of the present invention will be best understood by reference to the accompanying drawings wherein: 
           [0022]      FIG. 1  is a drawing showing prior art oval and square-shaped tips; 
           [0023]      FIG. 2  is a drawing showing several prior art needle cross-sectional configurations; 
           [0024]      FIG. 3  is an end view of a tip constructed in accordance with a preferred embodiment of the present invention; 
           [0025]      FIG. 4  is a partial sectional view of the tip shown in  FIG. 3  with a beveled configuration; and 
           [0026]      FIG. 5  is a partial sectional view of the tip shown in  FIG. 3  with a straight tip configuration. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0027]    Referring now to  FIG. 1 , the numeral  10  indicates generally a prior art phacoemulsification needle tip as shown in U.S. Pat. No. 6,007,555. Needle  10  terminates in a mouth  12  defined by a lip  14  at the end of needle body  16 , with lip  14  and needle body  16  formed as having an oval cross-section configuration. 
         [0028]    Referring to  FIG. 1 , the numeral  18  indicates generally a prior art phacoemulsification needle tip from U.S. Pat. No. 6,007,555, having a mouth  20  defined by a lip  22  at the end of needle  24 . The cross-sectional configuration of needle  18  and mouth  20  is a rectangle. 
         [0029]    Referring now to  FIG. 2 , the numeral  26  identifies several prior art phacoemulsification needles as described in U.S. Pat. No. 5,725,495, with needle  28  having a circular cross-section as shown at  30 , needle  32  having a triangular cross-section as shown at  34  and needle  36  having an octagonal cross-section as shown at  38 . 
         [0030]    Referring now to  FIG. 3 , the numeral  40  indicates generally a phacoemulsification needle tip embodying certain aspects of the present invention. In this example, tip  40  is circular in cross-section as seen in  FIG. 4  and has a circular wall  42  defining therewithin a cavity  44 . Tip  40  is integrally formed with a needle body  46  having a hollow passageway  48  communicating with cavity  44 . Wall  42  and cavity  44  define a lip  50  which, in turn, defines opening  52  communicating with cavity  44 . In the example shown in  FIG. 3 , lip  50  is angled with respect to axis A of tip  40  at an angle of about 30°. 
         [0031]    As seen in  FIGS. 3 and 4 , preferably, wall  42  has a first portion  56  having a first thickness and a second portion  58  having a second thickness. In the embodiment shown, the thickness of first wall portion  56  is less than the thickness of second wall portion  58 , the result of which is to form a land  54  extending circumferentially within cavity  44  and proximate lip  52 . In the configuration shown in  FIG. 3 , land  54  extends from first inner wall portion  56  to second inner wall portion  58 . The configuration in  FIG. 3  shows land  54  formed generally perpendicular with axis A although it should be understood that land  54  may be formed at other angles as well.  FIG. 3  also illustrates that when lip  52  is formed at a non-perpendicular angle to axis A, first inner wall portion  56  varies in length from a minimum length at  60  to a maximum length at  62 , meaning that land  54  is offset by a varying dimension from lip  50 . 
         [0032]    Referring now to  FIG. 5 , the numeral  64  identifies generally a phacoemulsification needle tip having an outer wall  66  defining a cavity  68  with tip  64  communicating with a needle body  70  having a central hollow passage  72  communicating with cavity  68 . 
         [0033]    Wall  66  defines a circular lip  74  which, in turn, defines an opening  76  communicating with cavity  68 . As described hereinabove, a first portion  82  of wall  66  extends distally from lip  76  and has a first thickness, and a second portion  84  of wall  66  has a second thickness with said first thickness being less than said second thickness. First and second wall portions  82 ,  84  meet to form a land  80  positioned within cavity  68  proximate lip  74 . 
         [0034]    As seen in  FIG. 5 , lip  74  is perpendicular to axis B of tip  64 . The angle at which lip  74  meets axis B may be selected to create a desired efficacy of operation. 
         [0035]    As seen in  FIG. 5 , second wall portion  84  tapers to meet needle body  70 . As seen in  FIG. 3 , second wall portion  58  tapers to meet needle body  46 . 
         [0036]    Each land  60 ,  80  defines thereby a cutting or emulsifying surface when tips  40 ,  64  are used. This is believed to enhance the cutting or emulsifying efficacy of tips  40 ,  64 . 
         [0037]    While the foregoing describes an example or examples of the present invention, it is to be understood that such description is made by way of example only and is not intended to limit the scope of the present invention. It is expected that alterations and further modifications, as well as other and further applications of the principles of the present invention will occur to others skilled in the art to which the invention relates and, while differing from the foregoing, remain within the spirit and scope of the invention as herein described and claimed. Where means-plus-function clauses are used in the claims such language is intended to cover the structures described herein as performing the recited functions and not only structural equivalents but equivalent structures as well. For the purposes of the present disclosure, two structures that perform the same function within an environment described above may be equivalent structures.